Benchtop study of leakages across the Portex, TaperGuard and Microcuff Endotracheal tubes under simulated clinical conditions
Lau AC, Lam SM, Yan WW. Hong Kong Med J. 2013 Jul 22.
OBJECTIVES. To compare three endotracheal tubes for leakage across the cuff (microaspiration) under a comprehensive set of simulated clinical situations. These were the Mallinckrodt TaperGuard (Covidien, US) with a tapered polyvinyl chloride cuff; the KimVent Microcuff (Kimberly-Clark Health Care, US) with a cylindrical polyurethane cuff, and a conventional Portex (Smiths Medical International Ltd, UK) with a globular polyvinyl chloride cuff.
DESIGN. A benchtop experimental study.
SETTING AND MATERIALS. A silicone cylinder serving as the model trachea was intubated with each of the three endotracheal tubes, one at a time. A total of 20 mL of water were added above the cuff and leakage measured every minute for 20 minutes under five simulated mechanical ventilation scenarios, including different positive end-expiratory pressure levels, and disconnection with and without spontaneous breathing efforts. Each scenario was studied under three cuff pressures of 10, 20 and 30 cm H2O, and then repeated with the application of a continuous suction force of 200 cm H2O, and leakage measured every minute for 3 minutes.
RESULTS. The outcome of interest was the cumulative amount of leakage. The Microcuff endotracheal tubes with an ultrathin polyurethane cuff consistently provided the best protection against microaspiration under all simulated clinical situations, followed by TaperGuard with a tapered cuff, and lastly Portex with a globular polyvinyl chloride cuff. Clinical scenarios associated with the greatest leakage were mechanical ventilation with zero positive end-expiratory pressure, circuit disconnection with spontaneous breathing efforts, application of suction, and a low cuff pressure.
CONCLUSIONS. Microcuff endotracheal tubes outperformed TaperGuard and Portex endotracheal tubes in preventing microaspiration, which is one of the major mechanisms for ventilator-associated pneumonia.
Timing for initiation of continuous renal replacement therapy in patients with septic shock and acute kidney injury
Shum HP, Chan KC, Kwan MC, Yeung AW, Cheung EW, Yan WW.; Ther Apher Dial. 2013 Jun;17(3):305-10.
The optimal timing for renal replacement therapy initiation in septic acute kidney injury (AKI) remains controversial. This study investigates the impact of early versus late initiation of continuous renal replacement therapy (CRRT) on organ dysfunction among patients with septic shock and AKI. Patients were dichotomized into "early" (simplified RIFLE Risk) or "late" (simplified RIFLE Injury or Failure) CRRT initiation. Patients with chronic kidney disease stage 5 or those on long-term dialysis were excluded. Organ dysfunction was quantified by Sequential Organ Failure Assessment (SOFA) score. From January 2008 to June 2011, 120 patients fulfilled the inclusion criteria. Thirty-one (26%) underwent "early" while 89 (74%) had "late" CRRT. No significant difference was noted between groups on improvement of total SOFA/non-renal SOFA score or noradrenaline equivalent in the first 24 and 48 h after CRRT initiation. Dialysis requirement and mortality (at 28 days, 3 months and 6 months) did not differ. In conclusion, improvement of non-renal SOFA score 48 h after CRRT correlated with SOFA score on CRRT initiation (P = 0.040) and APACHE IV risk of death (P = 0.000), but not estimated glomerular filtration rate on CRRT initiation (P = 0.377). Improvement of non-renal SOFA score correlated with SOFA score on CRRT initiation and APACHE IV risk of death. However, this retrospective review cannot identify any significant clinical benefit of early CRRT initiation in patients presenting with septic shock and AKI.
Application of endotoxin and cytokine adsorption haemofilter in septic acute kidney injury due to Gram-negative bacterial infection
Shum HP, Chan KC, Kwan MC, Yan WW.; Hong Kong Med J. 2013 May 6.
OBJECTIVE. Endotoxins and cytokines play an important role in the pathogenesis of multi-organ failure and mortality in patients suffering from severe Gram-negative bacterial infection. The aim of this study was to determine whether in patients with such infections, use of a haemofilter with enhanced endotoxin haemoadsorption and cytokine removal properties helps to overcome organ dysfunction.
DESIGN. Prospective case series study with historical controls.
SETTING. A regional hospital in Hong Kong.
PATIENTS. From October 2011 to June 2012, patients with sepsis-induced acute kidney injury due to Gram-negative bacteria were recruited. Continuous venovenous haemofiltration using oXiris haemofilter was performed. The patients' APACHE (Acute Physiology And Chronic Health Evaluation) II and inclusion criteria matched those of a series of selected historical controls who had been treated with continuous venovenous haemofiltration using polysulfone-based haemofilter from 2009 to 2011. The percentage reduction in the Sequential Organ Failure Assessment score by 24 and 48 hours, the percentage reduction of noradrenaline equivalent usage by 48 hours, as well as intensive care unit and hospital mortality in the two groups were compared.
RESULTS. Pre-treatment biochemical parameters and vasopressor use in the six patients undergoing the intervention and the 24 historical controls were similar. The mean circuit life of oXiris was about 61 hours. The Sequential Organ Failure Assessment score was significantly reduced by 37% at 48 hours post-initiation of oXiris-continuous venovenous haemofiltration versus an increment of 3% in the historical controls. No significant side-effect was detected. Mortality was similar in the two groups.
CONCLUSION. The haemofilter membrane with enhanced endotoxin adsorption and cytokine removal capacity was a safe alternative to traditional polysulfone-based continuous venovenous haemofiltration and expedited improvement in organ dysfunction.
Hyperimmune Intravenous Immunoglobulin Treatment: A Multicentre Double-Blind Randomized Controlled Trial for Patients with Severe A(H1N1)pdm09 Infection
Hung IF, To KK, Lee CK, Lee KL, Yan WW, Chan K, Chan WM, Ngai CW, Law KI, Chow FL, Liu R, Lai KY, Lau CC, Liu SH, Chan KH, Lin CK, Yuen KY.; Chest. 2013 Feb 28.
BACKGROUND Experience from influenza pandemics suggested that convalescent plasma treatment given within 4 to 5 days of symptom onset might be beneficial. However, robust treatment data is lacking.
METHODS This is a multicentre prospective double-blind randomized controlled trial. Convalescent plasma from patients who recovered from the 2009 pandemic influenza [A(H1N1)pdm09] infection was fractionated to hyperimmune intravenous immunoglobulin (H-IVIG) by CSL Biotherapies, Australia. Patients with severe A(H1N1)pdm09 infection on standard antiviral treatment requiring intensive care and ventilatory support were randomized to receive H-IVIG or normal IVIG manufactured before 2009 as control. Clinical outcome and adverse effects were compared.
RESULTS Between 2010 and 2011, thirty-five patients were randomized to receive H-IVIG (17 patients) or IVIG (18 patients). One defaulted patient was excluded from analysis. No adverse event related to treatment was reported. Baseline demographics and viral load before treatment were similar between the two groups. Serial respiratory viral load demonstrated that H-IVIG treatment was associated with significantly lower day 5 and 7 post-treatment viral load when compared to the control (p=0.04 and p=0.02 respectively). The initial serum cytokine level was significantly higher in the H-IVIG group but fell to similar level 3 days after treatment. Subgroup multivariate analysis of the 22 patients who received treatment within 5 days of symptom onset demonstrated that H-IVIG treatment was the only factor which independently reduced mortality [OR:0.14, 95% CI, 0.02-0.92; p=0.04].
CONCLUSIONS Treatment of severe A(H1N1)pdm09 infection with H-IVIG within 5 days of symptom onset was associated with a lower viral load and reduced mortality.ClinialTrials.gov (NCT01617317).
A retrospective review of the use of regional citrate anticoagulation in continuous venovenous hemofiltration for critically ill patients
Leung AK, Shum HP, Chan KC, Chan SC, Lai KY, Yan WW.; Crit Care Res Pract. 2013;2013:349512.
Background. The emergence of a commercially prepared citrate solution has revolutionized the use of RCA in the intensive care unit (ICU). The aim of this study was to evaluate the safety profile of a commercially prepared citrate solution.
Method. Predilution continuous venovenous hemofiltration (CVVH) was performed using Prismocitrate 10/2 at 2500 mL/h and a blood flow rate of 150 mL/min. Calcium chloride solution was infused to maintain ionized calcium within 1.0-1.2 mmol/L. An 8.4% sodium bicarbonate solution was infused separately. Treatment was stopped when the predefined clinical target was reached or the filter clotted.
Result. 58 sessions of citrate RCA were analyzed. The median circuit lifetime was 26.0 h (interquartile range IQR 21.2-44.3). The percentage of circuits lasting more than 12 h, 24 h, and 48 h was 94.6%, 58.9%, and 16.1%, respectively. There was no incidence of hypernatremia and median pH was <7.5. Hypomagnesemia and hypophosphatemia were detected in 41.6% and 17.6% of blood samples taken, respectively. Although 16 episodes had a total calcium/ionized calcium (total Ca/iCa) >2.5, only four patients had evidence of citrate accumulation.
Conclusion. The commercially prepared citrate solution could be used safely in critically ill patients who required CVVH with no major adverse events.
Ventilator Associated Pneumonia in Intensive Care Unit: Incidence, patient characteristics, outcome and validation of VAP-PIRO score in a local Chinese chort
Arthur Ming-Chit Kwan, King-Chung Chan, Arthur Chun-Wing Lau, Wing-Wa Yan; Crit Care & Shock 2012;15:111-9
Objective: Despite a systematic scoring system has been developed to assess the severity and to stratify the mortality risk of Ventilator-Associated Pneumonia (VAP), few clinical studies had published in validating this scoring system. We intend to study the incidence of VAP in a local Chinese cohort and to validate the VAP-PIRO (Predisposition, Insult, Response, Organ Dysfunction) score.
Design: A prospective, observational cohort study.
Setting: A 20-bed mixed medical-surgical adult Intensive Care Unit (ICU) of a regional referral centre serving 650,000 populations.
Patients and participants: 269 consecutive patients who had been intubated and mechanically ventilated for more than 24 hours during an 8-month study period.
Measurements and results: VAP was diagnosed by National Healthcare Safety Network (NHSN) PNU1 criteria. Clinical characteristics, medical resource use and outcome of the cohort were studied. The VAPPIRO score of each VAP case was calculated. The medical resource use and mortality in each PIRO risk group were compared. Of 269 patients admitted to ICU during the study period there were 59 VAP cases. The VAP incidence was 47.81 per 1,000 ventilator days. VAPPIRO score was unable to stratify medical resource use and mortality in our cohort.
Conclusion: VAP-PIRO score cannot significantly differentiate mortality and usage of medical resources in our cohort. This is likely due to the severity of VAP in our cohort is modest when compared to the original cohort.
Key words: Ventilator-Associated Pneumonia, Pneumonia, PIRO.
Regional citrate anticoagulation in predilution continuous venovenous hemofiltration using prismocitrate 10/2 solution
Ther Apher Dial. 2012 Feb;16(1):81-6.; Shum HP, Chan KC, Yan WW.
Regional citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT) is associated with a longer filter life and fewer bleeding events. Complexity of the regimen is the major hurdle preventing widespread application. This study describes a simple predilution continuous venovenous hemofiltration (CVVH) protocol utilizing a commercially prepared replacement solution containing citrate (Prismocitrate 10/2). Ten patients with acute renal failure were evaluated. The Prismaflex system was used for predilution CVVH, with Prismocitrate 10/2 running at 2500 mL/h as the main predilution replacement. An 8.4% sodium bicarbonate solution was infused at 50 mL/h in the first 2 h followed by 30 mL/h; 10% calcium gluconate was given to achieve an ionized calcium (iCa) level of 1-1.2 mmol/L. The circuit was run for 72 h unless there was filter clotting, transportation was required, or the patient did not require further CRRT. Total treatment duration was 504.5 h. The post-dilution equivalent ultrafiltration rate was 32.9 mL/kg/h (interquartile range [IQR] 31.6-38.2) and the median circuit life was 50.3 h (IQR 25.5-72.0). None of the circuit was changed due to circuit clotting. The median systemic iCa was 0.98 mmol/L (IQR 0.91-1.08). The total calcium-to-iCa ratio was 2.33 (IQR 2.21-2.45). None of the patients developed hypernatremia (Na ≥ 150 mmol/L) or citrate toxicity (total Ca-to-iCa ratio > 2.5 plus increasing metabolic acidosis), and metabolic alkalosis (pH ≥ 7.5) occurred in one patient. This simple RCA CVVH protocol using commercially-prepared solution could be a feasible, relatively safe, and effective alternative to the conventional regimen for patients with a body weight up to 80 kg.
Management of severe sepsis in patients admitted to Asian intensive care units: prospective cohort study
BMJ. 2011 Jun 13;342:d3245.MOSAICS Study Group
OBJECTIVES: To assess the compliance of Asian intensive care units and hospitals to the Surviving Sepsis Campaign's resuscitation and management bundles. Secondary objectives were to evaluate the impact of compliance on mortality and the organisational characteristics of hospitals that were associated with higher compliance.
DESIGN:Prospective cohort study.
SETTING: 150 intensive care units in 16 Asian countries.
PARTICIPANTS: 1285 adult patients with severe sepsis admitted to these intensive care units in July 2009. The organisational characteristics of participating centres, the patients' baseline characteristics, the achievement of targets within the resuscitation and management bundles, and outcome data were recorded.
MAIN OUTCOME MEASURE: Compliance with the Surviving Sepsis Campaign's resuscitation (six hours) and management (24 hours) bundles.
RESULTS: Hospital mortality was 44.5% (572/1285). Compliance rates for the resuscitation and management bundles were 7.6% (98/1285) and 3.5% (45/1285), respectively. On logistic regression analysis, compliance with the following bundle targets independently predicted decreased mortality: blood cultures (achieved in 803/1285; 62.5%, 95% confidence interval 59.8% to 65.1%), broad spectrum antibiotics (achieved in 821/1285; 63.9%, 61.3% to 66.5%), and central venous pressure (achieved in 345/870; 39.7%, 36.4% to 42.9%). High income countries, university hospitals, intensive care units with an accredited fellowship programme, and surgical intensive care units were more likely to be compliant with the resuscitation bundle.
CONCLUSIONS: While mortality from severe sepsis is high, compliance with resuscitation and management bundles is generally poor in much of Asia. As the centres included in this study might not be fully representative, achievement rates reported might overestimate the true degree of compliance with recommended care and should be interpreted with caution. Achievement of targets for blood cultures, antibiotics, and central venous pressure was independently associated with improved survival.
Interaction between fluid balance and disease severity on patient outcome in the critically ill
Shum HP, Lee FM, Chan KC, Yan WW. J Crit Care. 2011 Apr 20. [Epub ahead of print]
PURPOSE: There is evidence in literature regarding the benefits of immediate aggressive fluid resuscitation together with conservative fluid management approach after initial stabilization. This retrospective study assesses the relationship between fluid balance during intensive care unit (ICU) stay and outcomes among general critically ill patients. In addition, we also aim to see the effect of fluid gain among patients with different disease severity.
METHODS:A total of 639 patients admitted into ICU who stayed for 3 days or more were evaluated. Fluid balances during ICU stay were recorded. A logistic regression analysis was performed to identify significant factors associated with hospital mortality.
RESULTS: Acute Physiology and Chronic Health Evaluation IV predicted risk of death, fluid balance on the second plus third ICU days, and total fluid balance during ICU stay were positively associated with hospital death. Significant positive fluid balance on first ICU day, in contrast, was negatively associated with hospital mortality. The positive correlation between standardized mortality ratio (Acute Physiology and Chronic Health Evaluation IV) and fluid gain on the second plus third ICU days increases with disease severity.
CONCLUSION:Early adequate fluid resuscitation together with conservative late fluid management may provide better patient outcomes. The effect of fluid management strategy on patient outcome may depend on the underlying disease severity.
Convalescent plasma treatment reduced mortality in patients with severe pandemic influenza A (H1N1) 2009 virus infection
Hung IF, To KK, Lee CK, Lee KL, Chan K, Yan WW, Liu R, Watt CL, Chan WM, Lai KY, Koo CK, Buckley T, Chow FL, Wong KK, Chan HS, Ching CK, Tang BS, Lau CC, Li IW, Liu SH, Chan KH, Lin CK, Yuen KY.; Clin Infect Dis. 2011 Feb 15;52(4):447-56. Epub 2011 Jan 19.
BACKGROUND:Experience from treating patients with Spanish influenza and influenza A(H5N1) suggested that convalescent plasma therapy might be beneficial. However, its efficacy in patients with severe pandemic influenza A(H1N1) 2009 virus (H1N1 2009) infection remained unknown.
METHODS:During the period from 1 September 2009 through 30 June 2010, we conducted a prospective cohort study by recruiting patients aged ≥ 18 years with severe H1N1 2009 infection requiring intensive care. Patients were offered treatment with convalescent plasma with a neutralizing antibody titer of ≥ 1:160, harvested by apheresis from patients recovering from H1N1 2009 infection. Clinical outcome was compared with that of patients who declined plasma treatment as the untreated controls.
RESULTS:Ninety-three patients with severe H1N1 2009 infection requiring intensive care were recruited. Twenty patients (21.5%) received plasma treatment. The treatment and control groups were matched by age, sex, and disease severity scores. Mortality in the treatment group was significantly lower than in the nontreatment group (20.0% vs 54.8%; P = .01). Multivariate analysis showed that plasma treatment reduced mortality (odds ratio [OR], .20; 95% confidence interval [CI], .06-.69; P = .011), whereas complication of acute renal failure was independently associated with death (OR, 3.79; 95% CI, 1.15-12.4; P = .028). Subgroup analysis of 44 patients with serial respiratory tract viral load and cytokine level demonstrated that plasma treatment was associated with significantly lower day 3, 5, and 7 viral load, compared with the control group (P < .05). The corresponding temporal levels of interleukin 6, interleukin 10, and tumor necrosis factor α (P < .05) were also lower in the treatment group.
CONCLUSIONS:Treatment of severe H1N1 2009 infection with convalescent plasma reduced respiratory tract viral load, serum cytokine response, and mortality.
Management and prevention of spontaneous pneumothorax using pleurodesis in Hong Kong
Chan JW, Ko FW, Ng CK, Yeung A, Yee WK, So LK, Lam B, Wong MM, Choo KL, Ho AS, Tse PY, Fung SL, Lo CK, Yu WC.; Int J Tuberc Lung Dis. 2011 Mar;15(3):385-90.
BACKGROUND: The practice of pleurodesis for the management and prevention of spontaneous pneumothorax (SP) is uncertain.
DESIGN: A retrospective multicentre analysis of patients admitted to 12 hospitals in Hong Kong with SP in 2004 and who subsequently underwent pleurodesis for the same episode.
RESULTS: Pleurodesis was performed in 394 episodes. Initial medical chemical pleurodesis was performed for 258 (65.5%) patients ('initial medical group'), while 136 (34.5%) underwent initial surgical pleurodesis ('initial surgical group'). Secondary spontaneous pneumothorax (SSP; 237 episodes, 60.2%) was the most common indication for pleurodesis; it was also performed after a first episode of primary spontaneous pneumothorax (PSP) in 22 episodes (5.6%). Tetracycline derivatives (172 episodes, 66.7%) were the most popular sclerosing agents in the initial medical group. Those in the initial medical group were older and were more likely to be males, have SSP, chronic obstructive pulmonary disease and a history of past pleurodesis (P < 0.05) compared to the initial surgical group. Compared to the tetracycline group, more patients who initially received talc slurry had the procedure performed by surgeons, had larger (≥2 cm) pneumothorax or required suction during initial drainage (P < 0.05).
CONCLUSIONS: Despite the availability of international guidelines, there is considerable variation in pleurodesis for SP.
Cast nephropathy with acute renal failure treated with high cut-off haemodialysis in a patient with multiple myeloma.
Shum HP, Chan KC, Chow CC, Kho BC, Yan WW. Hong Kong Med J. 2010 Dec;16(6):489-92.
We report a case of a Chinese woman who presented with multiple myeloma and acute renal failure due to cast nephropathy, with an extremely high serum lambda free light chain concentration. She was successfully treated with chemotherapy and high cut-off extended haemodialysis. High cut-off haemodialysis is a new treatment modality which can achieve rapid free light chain clearance. This may contribute to a better renal outcome and overall prognosis for patients with multiple myeloma.
Minocycline and talc slurry pleurodesis for patients with secondary spontaneous pneumothorax
Ng CK, Ko FW, Chan JW, Yeung A, Yee WK, So LK, Lam B, Wong MM, Choo KL, Ho AS, Tse PY, Fung SL, Lo CK, Yu WC.; Int J Tuberc Lung Dis. 2010 Oct;14(10):1342-6.
SETTING: Few studies have evaluated the sclerosing efficacy of minocycline, and none have specifically compared its sclerosing efficacy and safety profiles with talc slurry in secondary spontaneous pneumothorax (SSP).
DESIGN: A retrospective analysis was conducted in patients with SSP who underwent chemical pleurodesis from January to December 2004 with minocycline or talc slurry in 12 public hospitals of Hong Kong.
RESULT: There were 121 episodes of minocycline pleurodesis and 64 episodes of talc slurry pleurodesis. Immediate procedural failure were similar in the minocycline and talc slurry groups (21.5% vs. 28.1%, P = 0.31). Presence of interstitial lung disease, ≥ 2 previous episodes of pneumothorax, requiring mechanical ventilation during pleurodesis and persistent air leak before pleurodesis were independently associated with procedural failure. Pain was experienced in respectively 44.6% and 37.5% of the minocycline and the talc slurry groups. Pain was more common in patients receiving high doses of talc (≥ 5 g; P = 0.03). Respiratory distress was found in respectively 1.7% and 1.6% of the minocycline and talc slurry groups.
CONCLUSION: Minocycline and talc slurry had comparable sclerosing efficacy in SSP, with immediate success rates of >70%. Pain was the most common adverse effect and respiratory distress was uncommon. Both appeared to be effective and safe for chemical pleurodesis in SSP.
Helen Hiu-Lam Wu, Kenny King-Chun Chan, Arthur Chun-Wing Lau, Wing-Wa Yan. Crit Care & Shock (2010) 13:81-90 (Link)
Objective: The aim of the present study was to investigate both the outcomes and prognostic factors of ARF patients requiring RRT in our Intensive Care Unit.
Design: It was a retrospective observational study. Setting: Pamela Youde Nethersole Eastern Hospital, a 20-bed medico-surgical ICU.
Patients and participants: ARF patients who had received RRT from January 2005 to December 2006 were recruited.
Interventions: The primary outcome was hospital mortality. Secondary outcomes were: dialysis dependency at hospital discharge, ICU and hospital length of stay. Relationship between demographics, premorbidities and clinical parameters with primary outcome was studied.
Measurements and results: One hundred and thirty-five patients were included in the final analysis. Hospital
mortality rate was 63.7%. The median survival was 24 days (IQR 7 to 746 days). Mechanical ventilation (HR
2.96, 95% CI 2.04 to 3.89) and hepatorenal syndrome (HR 2.29, 95% CI 1.63 to 2.95) were independently
associated with hospital mortality. Dialysis dependency rate after hospital discharge as on day 60 was 4.1%.
Conclusion: ARF in ICU was associated with a high mortality rate which was correlated with hepatorenal
syndrome and mechanical ventilation. Most of the hospital survivors were free from dialysis.
Hong Kong's experience on the use of extracorporeal membrane oxygenation for the treatment of influenza A (H1N1)
Chan KK, Lee KL, Lam PK, Law KI, Joynt GM, Yan WW.; Hong Kong Med J. 2010 Dec;16(6):447-54.
OBJECTIVE. To report Hong Kong's experience with the use of extracorporeal membrane oxygenation for the treatment of acute respiratory distress syndrome caused by influenza A (H1N1).
DESIGN. Multi-centred, retrospective observational study.
SETTING. Intensive care units in Hong Kong.
PATIENTS. Recipients of extracorporeal membrane oxygenation for confirmed influenza A (H1N1) infection from 1 May 2009 to 28 February 2010.
MAIN OUTCOME MEASURE. Hospital mortality.
RESULTS. During the study period, 120 patients were mechanically ventilated in intensive care units, among whom seven received veno-venous extracorporeal membrane oxygenation. The median (interquartile range) age of the latter patients was 42 (39-50) years, four had various chronic illnesses and one had a body mass index of greater than 30 kg/m2. The median (interquartile range) time from symptom onset to hospital admission was 5 (4-7) days. Corresponding values for the duration of extracorporeal membrane oxygenation, mechanical ventilation, intensive care unit stay, and hospital stay were 6 (6-10), 19 (11-25), 19 (18-30), and 31 (25-55) days, respectively. One patient died (hospital mortality, 14%) and six made full recoveries. All seven patients received oseltamivir; in addition three received intravenous zanamivir, four received convalescent plasma, and one received hyperimmune immunoglobulin. Nosocomial infection was the commonest complication. There was no life- or limb-threatening complication directly attributable to extracorporeal membrane oxygenation.
CONCLUSION. In response to the pandemic of influenza A (H1N1), some intensive care units in Hong Kong were able to offer extracorporeal membrane oxygenation to selected cases. In this small series, patient outcomes were similar to those reported in other observational studies, indicating that intensive care units in Hong Kong are capable of successfully introducing this technology. However, the cost-effectiveness and optimal delivery of this strategy remain uncertain.
Clostridium perfringens liver abscess with massive haemolysis.
Ng H, Lam SM, Shum HP, Yan WW. Hong Kong Med J. 2010 Aug;16(4):310-2.
Liver abscesses are commonly caused by Enterobacteriaceae and anaerobes. This report is of a patient with liver abscess with massive haemolysis and multiorgan failure caused by Clostridium perfringens. Despite the reportedly high mortality rate and poor prognostic factors, the patient eventually recovered with prompt treatment.
Triage decisions and outcomes for patients with Triage Priority 3 on the Society of Critical Care Medicine scale
Hoi-Ping Shum, King-Chung Chan, Chun-Wing Lau, Anne Kit-Hung Leung, Kin-Wai Chan and Wing-Wa Yan. Crit Care Resusc 2010; 12: 42–49.
Objective: To identify factors associated with the triage decision for patients classified as Society of Critical Care Medicine (SCCM) Triage Priority 3, and their outcomes.
Design: Single-centre, prospective, observational cohort study.
Setting: General intensive care unit in a tertiary regional hospital, over the 9 months January to September 2007.
Patients: SCCM Triage Priority 3 patients.
Results: All patients were followed up for at least 6 months. Among the 1346 triaged patients, 250 were classified as SCCM Triage Priority 3. Fewer than a third of these (76, 30.4%) were admitted to the ICU. Medical patients were more likely to be rejected than surgical or neurosurgical patients. Those with a poorer physicianpredicted chance of long-term survival were more likely to be rejected than those with a better predicted prognosis. The MPMII0-predicted mortality was higher for those denied ICU admission. Non-postoperative status (odds ratio [OR], 26.3) and physician-predicted risk > 50% of death within 1 month (OR, 11.8) were independently correlated with denial of ICU admission in a multiple logistic regression analysis. Cox regression analysis showed that independent risk factors for mortality were denial of ICU admission (hazard ratio [HR], 2.80), higher MPMII0-predicted mortality (HR, 1.12 for every 10% increment) and the presence of renal disease as an admission diagnosis (HR, 2.28).
Conclusions: For SCCM Triage Priority 3 patients, postoperative status and better physician-predicted prognosis correlated with ICU admission. Patients had lower medium-term survival if they were denied ICU admission, or had higher MPMII0-predicted mortality, or renal disease as the admission diagnosis.
Over 8 years experience on severe acute poisoning requiring intensive care in Hong Kong, China.
Lam SM, Lau AC, Yan WW.Hum Exp Toxicol. 2010 Feb 9. [Epub ahead of print]
In order to obtain up-to-date information on the pattern of severe acute poisoning and the characteristics and outcomes of these patients, 265 consecutive patients admitted to an intensive care unit in Hong Kong for acute poisoning from January 2000 to May 2008 were studied retrospectively. Benzodiazepine (25.3%), alcohol (23%), tricyclic antidepressant (17.4%), and carbon monoxide (15.1%) were the four commonest poisons encountered. Impaired consciousness was common and intubation was required in 67.9% of admissions, with a median duration of mechanical ventilation of less than 1 day. The overall mortality was 3.0%. Among the 257 survivors, the median lengths of stay in the intensive care unit and acute hospital (excluding days spent in psychiatric ward and convalescent hospital) were less than 1 day and 3 days, respectively. Factors associated with a longer length of stay included age of 65 or older, presence of comorbidity, Acute Physiology and Chronic Health Evaluation II score of 25 or greater, and development of shock, rhabdomyolysis, and aspiration pneumonia, while alcohol intoxication was associated with a shorter stay. This is the largest study of its kind in the Chinese population and provided information on the pattern of severe acute poisoning requiring intensive care admission and the outcomes of the patients concerned.
Management of patients admitted with pneumothorax: a multi-centre study of the practice and outcomes in Hong Kong
Chan JW, Ko FW, Ng CK, Yeung AW, Yee WK, So LK, Lam B, Wong MM, Choo KL, Ho AS, Tse PY, Fung SL, Lo CK, Yu WC.
OBJECTIVE: To examine the management practice of pneumothorax in hospitalised patients in Hong Kong, especially the choice of drainage options and their success rates, as well as the factors associated with procedural failures.
DESIGN: Retrospective study.
SETTING: Multi-centre study involving 12 public hospitals in Hong Kong.
PATIENTS: All adult patients admitted as an emergency in the year 2004 with a discharge diagnosis of 'pneumothorax' were included. Data on the management and outcomes of the various types of pneumothoraces were collected from their case records.
RESULTS: Altogether these patients had 1091 episodes (476 primary spontaneous pneumothoraces, 483 secondary spontaneous pneumothoraces, 87 iatrogenic pneumothoraces, and 45 traumatic pneumothoraces). Conservative treatment was offered in 182 (17%) episodes, which were more common among patients with small primary spontaneous pneumothoraces (71%). Simple aspiration was performed to treat 122 (11%) of such episodes, and had a success rate of 15%. Aspiration failure was associated with having a pneumothorax of size 2 cm or larger (odds ratio=3.7; 95% confidence interval, 1.2-11.5; P=0.03) and a smoking history (4.1; 1.2-14.3; P=0.03). Intercostal tube drainage was employed in 890 (82%) episodes, with a success rate of 77%. Failure of intercostal tube drainage was associated with application of suction (odds ratio=4.1; 95% confidence interval, 2.8-5.9; P<0.001) and presence of any tube complications (1.55; 1.0-2.3; P=0.03). Small-bore catheters (<14 French) were used in 12 (1%) of the episodes only. Tube complications were encountered in 214 (24%) episodes.
CONCLUSION: Notwithstanding recommendations from international guidelines, simple aspiration and intercostal tube drainage with small-bore catheters were not commonly employed in the management of hospitalised patients with the various types of pneumothoraces in Hong Kong.
Delayed Clearance of Viral Load and Marked Cytokine Activation in Severe Cases of Pandemic H1N1 2009 Influenza Virus Infection.
To KK, Hung IF, Li IW, Lee KL, Koo CK, Yan WW, Liu R, Ho KY, Chu KH, Watt CL, Luk WK, Lai KY, Chow FL, Mok T, Buckley T, Chan JF, Wong SS, Zheng B, Chen H, Lau CC, Tse H, Cheng VC, Chan KH, Yuen KY. Clin Infect Dis. 2010 Feb 5. [Epub ahead of print]
Background. Infections caused by the pandemic H1N1 2009 influenza virus range from mild upper respiratory tract syndromes to fatal diseases. However, studies comparing virological and immunological profile of different clinical severity are lacking. Methods. We conducted a retrospective cohort study of 74 patients with pandemic H1N1 infection, including 23 patients who either developed acute respiratory distress syndrome (ARDS) or died (ARDS-death group), 14 patients with desaturation requiring oxygen supplementation and who survived without ARDS (survived-without-ARDS group), and 37 patients with mild disease without desaturation (mild-disease group). We compared their pattern of clinical disease, viral load, and immunological profile. Results. Patients with severe disease were older, more likely to be obese or having underlying diseases, and had lower respiratory tract symptoms, especially dyspnea at presentation. The ARDS-death group had a slower decline in nasopharyngeal viral loads, had higher plasma levels of proinflammatory cytokines and chemokines, and were more likely to have bacterial coinfections (30.4%), myocarditis (21.7%), or viremia (13.0%) than patients in the survived-without-ARDS or the mild-disease groups. Reactive hemophagocytosis, thrombotic phenomena, lymphoid atrophy, diffuse alveolar damage, and multiorgan dysfunction similar to fatal avian influenza A H5N1 infection were found at postmortem examinations. Conclusions. The slower control of viral load and immunodysregulation in severe cases mandate the search for more effective antiviral and immunomodulatory regimens to stop the excessive cytokine activation resulting in ARDS and death.
Natalie YW Leung, Arthur CW Lau, Kenny KC Chan, WW Yan. Clinical characteristics and outcomes of obstetric patients admitted to the Intensive Care Unit: a 10-year retrospective review. Hong Kong Med J 2009;15:Epub 2009 Dec 8
Objective To review the characteristics and health-related quality-of-life outcomes of obstetric patients admitted to the Intensive Care Unit.
Design Retrospective cohort study.
Setting A regional hospital in Hong Kong.
Patients Consecutive obstetric patients admitted to the Intensive Care Unit of Pamela Youde Nethersole Eastern Hospital from January 1998 to December 2007.
Results Fifty obstetric patients (mean [standard deviation] age, 31  years; mean gestational age, 34  weeks) were analysed. The most common obstetric cause of admission was postpartum haemorrhage (n=19, 38%), followed by pregnancy-associated hypertension (n=7, 14%). The commonest non-obstetric cause of admission was sepsis (n=7, 14%). The commonest intervention was arterial line insertion (n=33, 66%) and mechanical ventilation (n=29, 58%). Maternal mortality was 6% (n=3), while the perinatal mortality rate was 8% (n=4). The average Short Form–36 Health Survey scores of our patients were lower than the norm for the Hong Kong population of the same age and gender. Conclusion Postpartum haemorrhage and pregnancy-associated hypertension were the most common causes of admission to our Intensive Care Unit. Overall mortality was low. Long-term
health-related quality of life in discharged patients was lower than the norm of the Hong Kong population. Appropriate antenatal care is important in preventing obstetric complications. Continued psychosocial follow-up of discharged patients has to be implemented.
Dr. Wing-wa YAN. Update of Renal Replacement Therapy in the ICU. The Hong Kong Medical Diary, vol 14, no 9, 13-18
In 2004, the term Acute Kidney Injury (AKI) was proposed to represent the entire spectrum of acute renal failure (ARF) with clinical manifestations ranging from a minimal elevation in serum creatinine to anuric renal failure.1 The reported prevalence of AKI in critically ill patients could be as high as 25% in some developed countries, and only about 4% of this group received renal replacement therapy (RRT), with an ensuing hospital mortality up to 60%. Controversies exist in many aspects of RRT for AKI despite decades of development. However, definitive findings on the dose of RRT were available last year. It is hoped that, with the continued international collaboration, a clearer picture would emerge in other areas of RRT.
Complete article here.
Dr LAM Sin Man Grace and Dr LAU Chun Wing Arthur, April 20092009 Alveolopleural or Bronchopleural Fistula - From the Critical Care Physicians' Perspective. Newsletter of The Hong Kong Thoracic Society, The American College of Chest Physicians (Hong Kong and Macau Chapter) and The Hong Kong Lung Foundation, vol 19, no 1, Mar/Apr 2009.
Introduction: In the following article, we illustrate the differences between alveolopleural fistula (APF) and bronchopleural fistula (BPF) with a review on their management through the presentation of a case recently encountered in the intensive care unit (ICU).
Case presentation: A 70-year-old ex-smoker with chronic obstructive pulmonary disease who was capable of caring for himself was admitted in September 2008 for his first episode of left-sided spontaneous pneumothorax. A chest drain was inserted, but the leak still had not healed by three weeks. He therefore underwent a video-assisted thoracoscopy (VAT). Intraoperatively, in an attempt to free the left lung from adhesions, the lung surface was torn and talc poudrage was thus abandoned. VAT was repeated one week later, but had to be converted to an open thoracotomy to identify the site of air leak, which was found at the apex of his left upper lobe. It was repaired and two new chest drains were inserted. Despite surgical repair, air leak persisted postoperatively. Two months into this admission, the patient developed right-sided spontaneous pneumothorax in addition to the persistent air leak on the left. Multiple chest drains were inserted into the right pleural cavity through which suction was applied. He developed respiratory failure two weeks later and was admitted to the ICU. Chest X-ray showed air-space consolidation in both lower lobes. The lungs were fully expanded, but air leak persisted bilaterally.
Complete article here.
Anne KH Leung, WW Yan. Renal replacement therapy in critically ill patients. Hong Kong Med J 2009; 15:122- 9
OBJECTIVE. To provide updated information (including on treatment) in relation to renal replacement therapy in critically ill patients.
DATA SOURCES AND STUDY SELECTION. Literature search of Medline and PubMed till June 2008.
DATA EXTRACTION. Original studies, literature review, and book chapters.
DATA SYNTHESIS. The prevalence of acute renal failure in critically ill patients remains high and mortality is up to 60%. Both the practice of renal replacement therapy (continuous against intermittent, haemofiltration against haemodialysis) and patient outcomes vary widely between studies. To better understand this heterogeneous group of patients, a unified classification of acute renal failure proposed by the Acute Dialysis Quality Initiative allows better understanding of the epidemiology and outcome of this disease. Similar to patients with chronic renal failure, there exists a direct relationship between the dose of dialysis and survival; 35 mL/kg/h is the accepted norm. However, this traditional practice is being challenged by recent trials. Although the use of citrate as anticoagulant in renal replacement therapy can prolong circuit patency and decrease bleeding risk, its use is limited by the complex set up and metabolic problems.
CONCLUSIONS. The RIFLE classification allows an accurate description of the epidemiology and outcome of critically ill patients with acute renal failure. The well-accepted continuous renal replacement therapy dose of 35 mL/kg/h in critically ill patients needs further verification from ongoing clinical trials. The complex set-up and the use of citrate anticoagulant has limited the use of such dialysis, which can nevertheless be overcome with the support of pharmaceutical companies.
Hong Kong Med J 2009;15:122-9
Key words: Critical illness; Kidney failure, acute; Renal dialysis; Renal replacement therapy; Treatment outcome
Ching-Kit Chan, Richard Li, HP Shum, Stanley HK Lo, Kenny KC Chan, KS Wong, TH Tsoi, WW Yan. Star fruit intoxication successfully treated by charcoal haemoperfusion and intensive haemofiltration. Hong Kong Med J 2009;15:149-52
We report on a case of an elderly woman with chronic renal impairment, secondary to diabetic nephropathy, who developed a deep coma and seizure shortly after consumption of star fruit. She was managed in the intensive care unit, and her consciousness level improved dramatically after an 8-hour charcoal haemoperfusion and 30 hours of continuous haemofiltration. There were no long-term neurological or renal sequelae 9 months later. Early recognition of this condition, intensive dialytic therapy and supportive measures, as well as early initiation of charcoal haemoperfusion may improve the management of this potentially treatable condition.
Key words: Diabetic nephropathies; Food poisoning; Fruit/poisoning; Kidney
Arthur Chun-Wing Lau, Wing-Wa Yan. Non-invasive Ventilation for Acute Respiratory Failure: Evidence and Experience. Medical Progress Nov, 2008, p 525 to 530
Introduction: Non-invasive positive-pressure ventilation (NIV) is the delivery of mechanically assisted breaths by non-invasive means (ie, without the
need for endotracheal intubation). Possible benefits of NIV include the avoidance of the complications of mechanical ventilation; enhancement of patient comfort; reductions in morbidity, mortality, intensive care unit (ICU) and hospital lengths of stay (LOS); and lower cost. In Hong Kong, NIV has been in common use for more than 15 years. Overseas, NIV was employed in 20% of ventilator starts, but utilization rates varied from 0% to 50% among different hospitals. The main reason for the low utilization rate was 'physicians' lack of knowledge'.1 This article reviews the evidence and summarizes the authors' experience of NIV use for acute respiratory failure.
BACKGROUND: In unconscious ventilated patients, various eye protective measures have been used to prevent corneal abrasions. Two randomized controlled studies in Australia had compared the effectiveness of polyethylene films and eye instillations to prevent corneal abrasions but results were inconsistent. The local acceptance of polyethylene films as a standard eye protective measure is still limited. OBJECTIVES: Our study aims to compare the effectiveness of polyethylene covers (Gladwrap) with lanolin (Duratears) eye ointment in the prevention of corneal abrasions in critically ill patients. DESIGN: A prospective randomized controlled study was conducted between April 2004 and December 2005. SETTING AND PARTICIPANTS: One hundred and twenty ventilated patients admitted to the intensive care unit (ICU) were randomly assigned to receive either polyethylene covers or lanolin eye ointment to prevent corneal abrasions. METHODS: All participants received a standard eye care regime together with the eye protective interventions. A fluorescein stain test was performed by the eye care team daily and then weekly to detect any corneal abrasions. RESULTS: Four participants were not included in the data analysis as they died soon after commencement of the study. A total of 116 patients were included in the final analysis. Of the seven patients (6.0%) that had a positive fluorescein test, four (6.8%) were in the polyethylene covers group (n=59) and three (5.3%) were in the lanolin eye ointment group (n=57). This was not statistically significant (p=0.519). One patient in the lanolin eye ointment group had an eye infection. Upon follow-up of those patients with positive fluorescein test results, two patients spontaneously converted to stain negative within 24h and two patients died before the ophthalmologist's assessment. The remaining three patients were diagnosed to have epithelial cell loss without corneal abrasions. CONCLUSIONS: With the implementation of a standardized eye care protocol, polyethylene cover is found to be equally effective in preventing corneal abrasions when compared with lanolin eye ointment. The additional benefit of polyethylene cover as a physical barrier to protect patients' eyes needed further evaluation.
A 53-year-old lady with blood-stained sputum and pleuritic pain had a lingular opacity on CXR which failed to resolve. A bronchial aspirate and transbronchial biopsy revealed features of bronchocentric granulomatosis with dichotomous branching hyphae suggestive of Aspergillus infection. However, subsequent fungal culture grew Pseudallescheria boydii. This case demonstrates the similarity of clinical and histological features caused by these two fungi. This appears to be the first reported case of pulmonary pseudallescheria with a bronchocentric granulomatous response.
Ching CK, Lai CK, Poon WT, Wong EN, Yan WW, Chan AY, Mak TW. Hazards posed by a banned drug--phenformin is still hanging around.Hong Kong Med J. 2008 Feb;14(1):50-4. Hospital Authority Toxicology Reference Laboratory, Princess Margaret Hospital, Laichikok, Hong Kong.
The Hospital Authority Toxicology Reference Laboratory confirmed six cases of phenformin use, with or without complications, from July 2005 to November 2006. Two of the patients presented with potentially fatal phenformin-induced lactic acidosis. Phenformin was found (or suspected to be) adulterating Chinese proprietary medicine in five of the six cases. We report these six cases to highlight the underrecognised hazards posed by phenformin, a banned drug in Hong Kong.
Lau AC, Ip MS, Lai CK, Choo KL, Tang KS, Yam LY, Chan-Yeung M. Variability of the prevalence of undiagnosed airflow obstruction in smokers using different diagnostic criteria. Chest. 2008 Jan;133(1):42-8. Epub 2007 Nov 7. Department of Intensive Care, The University of Hong Kong, Queen Mary Hospital Pokfulam, Hong Kong SAR, China.
PURPOSES: To estimate the prevalence of undiagnosed airflow obstruction (AFO) in Hong Kong smokers with no previous diagnosis of respiratory disease, and to assess its variability when applying different prediction equations and diagnostic criteria. METHODS: A multicenter, population-based, cross-sectional prevalence study was performed in smokers aged 20 to 80 years. Three different criteria (fixed 70% [Global Initiative for Chronic Obstructive Lung Disease and British Thoracic Society], fixed 75%, and European Respiratory Society [ERS]) were applied to define a lower limit of normal (LLN) of the FEV(1)/FVC ratio to compare with the Hong Kong Chinese reference equation (criterion 1), which had used a distribution-free method to obtain the lower fifth percentile of FEV(1)/FVC ratio as the LLN. RESULTS: In 525 male patients, using criterion 1 (local internal prediction equation) and defining AFO as FEV(1)/FVC less than LLN, the overall prevalence of AFO was 13.7%: 8.3% in age > or = 20 to 40 years, 14.0% in age > or = 40 to 60 years, and 17.8% in age > or = 60 to 80 years. When the local internal prediction equation was used as the comparison reference, the fixed-ratio methods tended to miss AFO in younger age groups and overdiagnose AFO in old age, while the ERS criteria, which uses an almost lower fifth percentile-equivalent method, showed less of such a trend but still only showed moderate agreement with criterion 1. CONCLUSIONS: Undiagnosed AFO was prevalent in Hong Kong smokers. Estimated prevalence rates were highly affected by the criteria used to define AFO. The predicted lower fifth percentile values calculated from a local reference equation as the LLN of FEV(1)/FVC ratio should be used for the diagnosis of AFO.
Lithium overdose causing non-convulsive status epilepticus--the importance of lithium levels and the electroencephalography in diagnosis
Yip KK, Yeung WT. Hong Kong Med J. 2007 Dec;13(6):471-4.
We report a case of lithium overdose in a patient who presented in non-convulsive status epilepticus. The lithium toxicity was probably due to interaction with Moduretic. The diagnosis was not suspected until electroencephalography was performed. This case underscores the importance of therapeutic drug level monitoring of lithium, especially where toxicity is suspected, and the indispensable role electroencephalography plays by allowing a correct diagnosis to be made promptly.
BACKGROUND AND OBJECTIVE: This study was conducted to define normal reference values and lower limits of normal (LLN) for single-breath carbon monoxide diffusing capacity (DLco) and DLco per unit of alveolar volume (Kco) for Chinese adults in Hong Kong. METHODS: Healthy non-smoking men and women aged 18-80 years were recruited by random digit dialing. DLco and Kco were measured according to American Thoracic Society standards. Reference equations were obtained by multiple linear regression; LLN were derived by distribution-free method for estimation of age-related centiles. RESULTS: Tests from 568 subjects (259 men, 309 women) were analysed. DLco declined with age in both genders, and increased with height and the interaction term of height and age in men and women, respectively. Considering Hb values did not improve the reference equations. Kco declined with age and increased with weight in both genders, while height and its interaction term with age were additional determinants in women. The reference DLco was lower than some Caucasian values, and was only explained partially by a smaller body size and alveolar volume in Chinese. The distribution-free method yielded better overall approximation to the fifth percentile compared with the traditional method of determining LLN. CONCLUSIONS: The equations for reference values and LLN of diffusing capacity derived in this study are of clinical relevance to Chinese subjects.
Yam LY, Lau AC, Lai FY, Shung E, Chan J, Wong V; Hong Kong Hospital Authority SARS Collaborative Group (HASCOG). Corticosteroid treatment of severe acute respiratory syndrome in Hong Kong. J Infect. 2007 Jan;54(1):28-39. Epub 2006 Mar 15. Division of Respiratory and Critical Care Medicine, Department of Medicine, Pamela Youde Nethersole Eastern Hospital, 3 Lok Man Road, Hong Kong SAR, China.
BACKGROUND: The patterns of corticosteroids usage in severe acute respiratory syndrome (SARS) and associated treatment outcomes in Hong Kong were studied. METHOD: Patients> or =18 years old who either had not received corticosteroid or had taken corticosteroids within 14 days from symptom onset were included. Patients receiving corticosteroids beyond 15 days or other investigational treatment within 21 days from symptom onset were excluded. Of 1313 eligible patients, 1287 with major corticosteroid dosage-type combinations were analysed. RESULTS: Crude death rate was lower among 1188 steroid-treated patients compared to 99 patients in Group No Steroid (17.0% vs. 28.3%). Among four corticosteroid groups studied, mortality was lowest in the low-dose oral prednisolone (Group P) and high-dose methylprednisolone (Group MP) groups. On multivariate analysis of the corticosteroid groups, independent factors related to death were: corticosteroid group, older age, co-morbidity, worse chest X-ray score, worse respiratory status at Days 8-10 and higher admission white cell count. Again Groups P and MP had significantly lower adjusted odds ratios for death and lower bacterial and fungal culture rates. Despite worse chest X-ray scores and higher cumulative corticosteroid dosages in Group MP compared to Group P, fewer patients required rescue pulsed corticosteroid. Patients on hydrocortisone (Group HC) had the highest positive culture rates. CONCLUSION: We speculate that corticosteroid with higher in-vitro inflammatory potency administered at timing and dosages commensurate with disease severity may be conducive to better outcome from SARS as a consequence of more effective control of immunopathological lung damage.
STUDY OBJECTIVES: The accuracy of reference values of lung function is important for assessment of severity and functional impairment of respiratory diseases. The aim of the study was to establish updated prediction formulae of spirometric parameters for Hong Kong Chinese and to compare the reference values with those derived from other studies in white and Chinese subjects. DESIGN: Cross-sectional multicenter study. SETTING: Lung function laboratories of eight regional hospitals in Hong Kong. PARTICIPANTS: Subjects were recruited by random-digit dialing. One thousand one hundred seventy-six subjects who fulfilled recruitment criteria underwent spirometry. MEASUREMENTS: Spirometry was performed according to American Thoracic Society recommendations, and the technique was standardized among the eight participating lung function laboratories. RESULTS: Evaluable data of 1,089 (494 men and 595 women) healthy nonsmokers aged 18 to 80 years were analyzed. Age and height were found to be the major determinants of FEV1 and FVC, with a linear decline of height-adjusted values with age in both sexes. Spirometric values of this population have increased compared to Chinese populations of similar sex, age, and height two decades ago. Reference values derived from white populations were higher than our values by 5 to 19%, and the degree of overestimation varied with age, sex, and lung function parameter. We also demonstrated that the blanket application of correction factors for Asian populations may not be appropriate. In this study cohort, the distribution-free estimation of age-related centiles was more appropriate for the determination of lower limits of normal. CONCLUSIONS: Our findings underscore the need to use reference values based on updated data derived from local populations or those matched for ethnicity and other sociodemographic characteristics.
Lau AC, Yam LY, So LK. Management of Critically Ill Patients with Severe Acute Respiratory Syndrome (SARS). Int J Med Sci. 2004;1(1):1-10. Epub 2004 Mar 10. Division of Respiratory and Critical Care Medicine, Department of Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, PR China.
Severe acute respiratory syndrome (SARS) is frequently complicated with acute respiratory failure. In this article, we aim to focus on the management of the subgroup of SARS patients who are critically ill. Most SARS patients would require high flow oxygen supplementation, 20-30% required intensive care unit (ICU) or high dependency care, and 13-26% developed acute respiratory distress syndrome (ARDS). In some of these patients, the clinical course can progress relentlessly to septic shock and/or multiple organ dysfunction syndrome (MODS). The management of critically ill SARS patients requires timely institution of pharmacotherapy where applicable and supportive treatment (oxygen therapy, noninvasive and invasive ventilation). Superimposed bacterial and other opportunistic infections are common, especially in those treated with mechanical ventilation. Subcutaneous emphysema, pneumothoraces and pneumomediastinum may arise spontaneously or as a result of positive ventilatory assistance. Older age is a consistently a poor prognostic factor. Appropriate use of personal protection equipment and adherence to infection control measures is mandatory for effective infection control. Much of the knowledge about the clinical aspects of SARS is based on retrospective observational data and randomized-controlled trials are required for confirmation. Physicians and scientists all over the world should collaborate to study this condition which may potentially threaten human existence.
OBJECTIVES: To study the effectiveness of noninvasive positive pressure ventilation (NIPPV) in the treatment of acute respiratory failure (ARF) in severe acute respiratory syndrome (SARS), and the associated infection risk. METHODS: All patients with the diagnosis of probable SARS admitted to a regional hospital in Hong Kong from March 9 to April 28, 2003, and who had SARS-related respiratory distress complications were recruited for NIPPV usage. The health status of all health-care workers working in the NIPPV wards was closely monitored, and consent was obtained to check serum for coronavirus serology. Patient outcomes and the risk of SARS transmission to health-care workers were assessed. RESULTS: NIPPV was applied to 20 patients (11 male patients) with ARF secondary to SARS. Mean age was 51.4 years, and mean acute physiology and chronic health evaluation II score was 5.35. Coronavirus serology was positive in 95% (19 of 20 patients). NIPPV was started 9.6 days (mean) from symptom onset, and mean duration of NIPPV usage was 84.3 h. Endotracheal intubation was avoided in 14 patients (70%), in whom the length of ICU stay was shorter (3.1 days vs 21.3 days, p < 0.001) and the chest radiography score within 24 h of NIPPV was lower (15.1 vs 22.5, p = 0.005) compared to intubated patients. Intubation avoidance was predicted by a marked reduction in respiratory rate (9.2 breaths/min) and supplemental oxygen requirement (3.1 L/min) within 24 h of NIPPV. Complications were few and reversible. There were no infections among the 105 health-care workers caring for the patients receiving NIPPV. CONCLUSIONS: NIPPV was effective in the treatment of ARF in the patients with SARS studied, and its use was safe for health-care workers.
Tse TS, Tsui KL, Yam LY, So LK, Lau AC, Chan KK, Li SK. Occult pneumomediastinum in a SARS patient presenting as recurrent chest pain and acute ECG changes mimicking acute coronary syndrome. Respirology. 2004 Jun;9(2):271-3. Department of Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong SAR, China.
OBJECTIVE: Severe acute respiratory syndrome (SARS) is a newly emergent disease due to a novel coronavirus, which caused outbreaks worldwide. METHODOLOGY: We report a SARS patient who had developed recurrent chest pain and acute T-wave inversion over the precordial leads on electrocardiography (ECG). Results: She developed progressive subcutaneous emphysema a few days later. Her CXR showed features suggestive of pneumomediastinum, which was confirmed by high-resolution CT scan of the thorax. CONCLUSION: Pneumomediastinum should be considered in SARS patients as a possible cause of chest pain and ECG changes that mimic acute coronary syndrome.
OBJECTIVE: There is so far no consensus on the optimal treatment strategy for the coronavirus-associated severe acute respiratory syndrome (SARS). We aimed to analyse the outcomes of a standard treatment strategy comprising antibiotics, a combination of ribavirin, a 3-week step-down course of corticosteroids, and the possibility of pulsed methylprednisolone rescue in the event of deterioration. METHODOLOGY: This was a prospective cohort study performed at a major public-funded hospital in Hong Kong. Eighty-eight World Health Organisation/Centers for Disease Control and Prevention probable cases of SARS (97% laboratory-confirmed) were treated with a standard protocol previously reported. Seventy-one patients treated de novo were analysed in detail with regard to time to clinical stabilization after combination treatment, requirement of additional therapy (pulsed methylprednisolone; assisted ventilation); and final outcomes (recovery, mortality). RESULTS: The mean age was 42. Twenty-one patients (24%) had comorbidities. Three of 71 treated de novo recovered with antibiotics alone. The remaining 68 received combination treatment at a mean of 5.8 days after symptom onset, of whom 30 subsequently required pulsed methylprednisolone rescue (independent predictors: older age and higher LDH) and 18 required assisted ventilation (independent predictors: older age, higher oxygen requirement and creatinine level). Their median time to clinical stabilization was 8.0 days after combination treatment (independent predictor for longer time to stabilization: median age of 41 or above). Common complications were hyperglycaemia (58%), pneumo-mediastinum/thoraces (13%), psychiatric manifestations (7%) and ventilator-associated pneumonia (2%). One patient (1%) died of SARS-related respiratory failure. All-cause mortality was 3.4%, occurring in patients aged > 65 years only. None of the discharged survivors required continuation of oxygen therapy. CONCLUSIONS: This standard treatment protocol resulted in overall satisfactory outcomes. Randomized controlled trial is suggested to confirm its efficacy.
STUDY OBJECTIVE: Microalbuminuria in diabetes mellitus is a risk factor for cardiovascular disease. We hypothesized that microalbuminuria in type 2 diabetic patients is related to impaired cardiopulmonary function during exercise, and that the severity of impairment is correlated with the degree of microalbuminuria. DESIGN: Twenty of each of the following categories of subjects performed symptom-limited cardiopulmonary exercise testing on a cycle ergometer: (1) type 2 diabetic patients with normoalbuminuria (daily urinary albumin excretion [UAE] < 30 mg/d); (2) type 2 diabetic patients with microalbuminuria (daily UAE, 30 to 300 mg/d); and (3) normal control subjects. MEASUREMENTS AND RESULTS: Oxygen consumption (VO(2)) of patients with microalbuminuria was lower than that of control subjects at anaerobic threshold (AT) [p < 0.001], and was lower than both control subjects (p < 0.001) and patients with normoalbuminuria (p = 0.015) at peak exercise. There was a progressive worsening in gas exchange efficiency at the lungs, as measured by minute ventilation (VE)/carbon dioxide production (VCO(2)) at AT or DeltaVE/DeltaVCO(2) slope, (p = 0.006 and p = 0.019, respectively) going from control subjects to patients with normoalbuminuria and then to patients with microalbuminuria. Left ventricular ejection fractions and BP were similar in patients with normoalbuminuria and microalbuminuria. More patients with microalbuminuria (n = 9) than with normoalbuminuria (n = 2) demonstrated diastolic dysfunction (p = 0.013). These 11 patients had lower peak VO(2) values (p = 0.001) and higher daily UAE (p = 0.028). An inverse linear relationship was found between peak VO(2) and log(10) daily UAE (r = - 0.57, r(2) = 0.29, p < 0.001). CONCLUSIONS: Abnormalities reflecting reduced oxygen transport and impaired gas exchange efficiency were found during exercise, and were especially profound in patients with microalbuminuria. These changes could be secondary to pulmonary microangiopathy and myocardial interstitial changes. Increases in capillary permeability to proteins may take place in the myocardium as they do in the kidneys, and contribute to impaired myocardial distensibility and hence diastolic dysfunction.
Chun-Wing Lau A, So LK, Yam LY, Chan KS. Response to published article. J Infect. 2005 Oct 3; [Epub ahead of print]
So LKY, Lau ACW, Yam LYC. Chapter 9, Treatment of Severe Acute Respiratory Syndrome, in Kamps BS, Hoffmann C. SARS Reference, Flying publisher. www.sarsreference.com (Book Chapter)
ACW Lau, LKY So, LYC Yam. Chapter 10: Current Status of Therapy of SARS, in: Coronoviruses with Special Emphasis on First Insights Concerning SARS. Schmidt A, Wolff (vol eds) 2004, Birkhauser Publishers Ltd, Switzerland. (Book Chapter)
Arthur Chun-Wing LAU, Ida Kam-Siu, Man-Ching LI, Mary WAN, Alfred Wing-Hang SIT, Rodney Allan LEE, Raymond Wai-Hung YUNG, Loretta Yin-Chun YAM. Response to SARS as a prototype for bioterrorism: Lessons Learnt in a Regional Hospital in Hong Kong. Elsevier Scientific, Inc. (Book Chapter)
A series of 31 patients with probable SARS, diagnosed from WHO criteria, were treated according to a treatment protocol consisting of antibacterials and a combination of ribavirin and methylprednisolone. Through experience with the
first 11 patients, we were able to finalise standard dose regimens, including pulsed methylprednisolone. One patient recovered on antibacterial treatment alone, 17 showed rapid and sustained responses, and 13 achieved improvement with step-up or pulsed methylprednisolone. Four patients required short periods of non-invasive ventilation. No patient required intubation or mechanical ventilation. There was no mortality or treatment morbidity in this series.
A retrospective study was carried out in a Hong Kong regional hospital with 24-h emergency service, to study the factors associated with shorter time to re-admission after acute exacerbation of chronic obstructive pulmonary disease (COPD). From 1 January 1997 to 31 December 1997, the first admission (index admission) of each patient through the emergency room with COPD/chronic bronchitis/emphysema was included. A total of 551 patients fulfilled the inclusion criteria. The total acute and rehabilitative length of stay (mean +/- SD) was 9.41+/-11.67 days. Within 1 year after discharge, 327 patients (59 35%) were re-admitted at least once. Median time to first re-admission after discharge was 240 days. By Cox regression analysis, the following factors were independently associated with shorter time to re-admission: hospital admission within 1 year before index admission, total length of stay in index admission > 5 days, nursing home residency, dependency in self-care activities, right heart strain pattern on electrocardiogram, on high dose inhaled corticosteroid and actual bicarbonate level > 25 mmol l(-1). These factors may be relevant in the future planning of healthcare utilization for COPD patients.
Cheng F, Ip M, Wong KK, Yan WW.Critical care ethics in Hong Kong: cross-cultural conflicts as east meets west.J Med Philos. 1998 Dec;23(6):616-27. Comment in: J Med Philos. 1998 Dec;23(6):628-42.
The practice of critical care medicine has long been a difficult task for most critical care physicians in the densely populated city of Hong Kong, where we face limited resources and a limited number of intensive care beds. Our triage decisions are largely based on the potential of functional reversibility of the patients. Provision of graded care beds may help to relieve some of the demands on the intensive care beds. Decisions to forego futile medical treatment are frequently physician-guided family-based decisions, which is quite contrary to the Western focus on patient autonomy. However, as people acquire knowledge about health care and they become more aware of individual rights, our critical care doctors will be able to narrow the gaps between the different concepts of medical ethics among our professionals as well as in our society. An open and caring attitude from our intensivists will be important in minimizing the cross-cultural conflict on the complex issue of medical futility.