Prediction of hospital mortality among critically ill patients in a single centre in Asia: comparison of artificial neural networks and logistic regression-based model.

INTRODUCTION: This study compared the performance of the artificial neural network (ANN) model with the Acute Physiologic and Chronic Health Evaluation (APACHE) II and IV models for predicting hospital mortality among critically ill patients in Hong Kong. METHODS: This retrospective analysis included all patients admitted to the intensive care unit of Pamela Youde Nethersole Eastern Hospital from January 2010 to December 2019. The ANN model was constructed using parameters identical to the APACHE IV model. Discrimination performance was assessed using area under the receiver operating characteristic curve (AUROC); calibration performance was evaluated using the Brier score and Hosmer-Lemeshow statistic. RESULTS: In total, 14 503 patients were included, with 10% in the validation set and 90% in the ANN model development set. The ANN model (AUROC=0.88, 95% confidence interval [CI]=0.86-0.90, Brier score=0.10; P in Hosmer-Lemeshow test=0.37) outperformed the APACHE II model (AUROC=0.85, 95% CI=0.80-0.85, Brier score=0.14; P<0.001 for both comparisons of AUROCs and Brier scores) but showed performance similar to the APACHE IV model (AUROC=0.87, 95% CI=0.85-0.89, Brier score=0.11; P=0.34 for comparison of AUROCs, and P=0.05 for comparison of Brier scores). The ANN model demonstrated better calibration than the APACHE II and APACHE IV models. CONCLUSION: Our ANN model outperformed the APACHE II model but was similar to the APACHE IV model in terms of predicting hospital mortality in Hong Kong. Artificial neural networks are valuable tools that can enhance real-time prognostic prediction.

Twenty-eight-day mortality among patients with severe or critical COVID-19 in Hong Kong during the early stages of the pandemic.

INTRODUCTION: In 2020, patients with critical coronavirus disease 2019 (COVID-19) had a 28-day mortality rate of 30% to 50% worldwide; outcomes among such patients in Hong Kong were unknown. This study investigated 28-day mortality and corresponding risk factors among patients with severe or critical COVID-19 in Hong Kong. METHODS: This retrospective cohort study included adult patients with severe or critical COVID-19 who were admitted to three public hospitals in Hong Kong from 22 January to 30 September 2020. Demographics, comorbidities, symptoms, treatment, and outcomes were examined. RESULTS: Among 125 patients with severe or critical COVID-19, 15 (12.0%) died within 28 days. Overall, the median patient age was 64 years; 48.0% and 54.4% of patients had hypertension and obesity, respectively. Respiratory samples were confirmed severe acute respiratory syndrome coronavirus 2 RNA-positive after a median of 3 days. The most common presenting symptom was fever (80.0% of patients); 45.6% and 32.8% of patients received care in intensive care unit and required mechanical ventilation, respectively. In logistic regression analysis comparing 28-day survivors and non-survivors, factors associated with greater 28-day mortality were older age (odds ratio [OR] per 1-year increase in age=1.12, 95% confidence interval [CI]=1.04-1.21; P=0.002), history of stroke (OR=15.96, 95% CI=1.65-154.66; P=0.017), use of renal replacement therapy (OR=15.32, 95% CI=2.67-87.83; P=0.002), and shorter duration of lopinavir-ritonavir treatment (OR per 1-day increase=0.82, 95% CI=0.68-0.98; P=0.034). CONCLUSION: The 28-day mortality rate among patients with severe or critical COVID-19 in Hong Kong was 12.0%. Older age, history of stroke, use of renal replacement therapy, and shorter duration of lopinavir-ritonavir treatment were independent predictors of 28-day mortality.

Ten-year territory-wide trends in the utilisation and clinical outcomes of extracorporeal membrane oxygenation in Hong Kong.

INTRODUCTION: The utilisation of extracorporeal membrane oxygenation (ECMO) has been rapidly increasing in Hong Kong. This study examined 10-year trends in the utilisation and clinical outcomes of ECMO in Hong Kong. METHODS: We retrospectively reviewed the records of all adult patients receiving ECMO who were admitted to the intensive care units (ICUs) of public hospitals in Hong Kong between 2010 and 2019. Temporal trends across years were assessed using the Mann-Kendall test. Observed hospital mortality was compared with the Acute Physiology and Chronic Health Evaluation (APACHE) IV-predicted mortality. RESULTS: The annual number of patients receiving ECMO increased from 18 to 171 over 10 years. In total, 911 patients received ECMO during the study period: 297 (32.6%) received veno-arterial ECMO, 450 (49.4%) received veno-venous ECMO, and 164 (18.0%) received extracorporeal cardiopulmonary resuscitation. The annual number of patients aged ≥65 years increased from 0 to 47 (27.5%) [P for trend=0.001]. The median (interquartile range) Charlson Comorbidity Index increased from 1 (0-1) to 2 (1-3) [P for trend<0.001] while the median (interquartile range) APACHE IV score increased from 90 (57-112) to 105 (77-137) [P for trend=0.003]. The overall standardised mortality ratio comparing hospital mortality with APACHE IV-predicted mortality was 1.11 (95% confidence interval=1.01-1.22). Hospital and ICU length of stay both significantly decreased (P for trend=0.011 and <0.001, respectively). CONCLUSION: As ECMO utilisation increased in Hong Kong, patients put on ECMO were older, more critically ill, and had more co-morbidities. It is important to combine service expansion with adequate resource allocation and training to maintain quality of care.

Admission triage tool for adult intensive care unit admission in Hong Kong during the COVID-19 outbreak.

Intensive care is expensive, and the numbers of intensive care unit (ICU) beds and trained specialist medical staff able to provide services in Hong Kong are limited. The most recent increase in coronavirus disease 2019 (COVID-19) infections over July to August 2020 resulted in more than 100 new cases per day for a prolonged period. The increased numbers of critically ill patients requiring ICU admission posed a capacity challenge to ICUs across the territory, and it may be reasonably anticipated that should a substantially larger outbreak occur, ICU services will be overwhelmed. Therefore, a transparent and fair prioritisation process for decisions regarding patient ICU admission is urgently required. This triage tool is built on the foundation of the existing guidelines and framework for admission, discharge, and triage that inform routine clinical practice in Hospital Authority ICUs, with the aim of achieving the greatest benefit for the greatest number of patients from the available ICU resources. This COVID-19 Crisis Triage Tool is expected to provide structured guidance to frontline doctors on how to make triage decisions should ICU resources become overwhelmed by patients requiring ICU care, particularly during the current COVID-19 pandemic. The triage tool takes the form of a detailed decision aid algorithm based on a combination of established prognostic scores, and it should increase objectivity and transparency in triage decision making and enhance decision-making consistency between doctors within and across ICUs in Hong Kong. However, it remains an aid rather than a complete substitute for the carefully considered judgement of an experienced intensive care clinician.

Impact of appropriate empirical antibiotics on clinical outcomes in Klebsiella pneumoniae bacteraemia.

INTRODUCTION: Klebsiella pneumoniae infections can cause septic shock, multiorgan failure, and death. METHODS: This retrospective cohort study included adults with K pneumoniae bacteraemia treated from 1 January 2009 to 30 June 2017. Demographics, microbiology, and outcomes were analysed. The primary outcome was 90-day all-cause mortality; secondary outcomes were intensive care unit (ICU) and hospital mortalities, ICU and hospital lengths of stay, and ICU ventilator duration. RESULTS: In total, 984 patients had K pneumoniae bacteraemia; of them, 686 received appropriate empirical antibiotics. Overall, 205 patients required intensive care. Older age (odds ratio [OR]=1.60; 95% confidence interval [CI]=1.120-2.295; P=0.010), chronic kidney disease (OR=1.81; 95% CI=1.181- 2.785; P=0.007), mechanical ventilation (OR=1.79; 95% CI=1.188-2.681; P=0.005), pneumonia (OR=1.50; 95% CI=1.030-2.187; P=0.034), and carbapenem-resistant or extended-spectrum betalactamase (ESBL)-producing isolates (OR=12.51; 95% CI=7.886-19.487; P<0.001) were associated with greater risk of inappropriate empirical treatment. Ninety-day mortality was significantly higher among patients with inappropriate empirical treatment; independent predictors included pneumonia (hazard ratio [HR]=2.94; 95% CI=2.271-3.808; P<0.001), gastrointestinal infection (HR=2.77; 95% CI=2.055-3.744; P<0.001), failed empirical antibiotics (HR=2.45; 95% CI=1.928-3.124; P<0.001), older age (HR=1.79; 95% CI=1.356-2.371; P<0.001), solid tumour (HR=1.77; 95% CI=1.401-2.231; P<0.001), carbapenem-resistant or ESBL-producing isolates (HR=1.64; 95% CI=1.170-2.297; P=0.004), patients admitted through the Department of Medicine (HR=1.39; 95% CI=1.076-1.800; P=0.012), and higher total Sequential Organ Failure Assessment score (HR=1.09; 95% CI=1.058-1.112; P=0.023). Among ICU patients, inappropriate empirical antibiotic treatment was significantly associated with increased ventilator duration and 90-day mortality. CONCLUSIONS: Klebsiella pneumoniae bacteraemia was associated with high 90-day and ICU mortalities; 90-day mortality increased with inappropriate empirical antibiotic treatment.

Burden of pneumococcal disease: 8-year retrospective analysis from a single centre in Hong Kong.

PURPOSE: Streptococcus pneumoniae is a common pathogen involved in community-acquired pneumonia. Invasive pneumococcal disease is often associated with higher co-morbidity rates, but mortality-related findings have been inconclusive. This study investigated predictors of 30-day mortality and invasive pneumococcal disease. METHODS: This retrospective analysis included adults with pneumococcal disease who were admitted to Pamela Youde Nethersole Eastern Hospital from 1 January 2011 to 31 December 2018. Demographics, microbiological characteristics, and outcomes were compared between 30-day survivors and non-survivors, and between patients with invasive disease and those with non-invasive disease. Intensive care unit (ICU) subgroup analysis was performed. The primary outcome was 30-day all-cause mortality; secondary outcomes were ICU and hospital mortalities, and ICU and hospital lengths of stay. RESULTS: In total, 792 patients had pneumococcal disease; 701 survived and 91 (11.5%) died within 30 days. Notably, 106 (13.4%) patients had invasive pneumococcal disease and 170 (21.5%) patients received intensive care. Vasopressor use (odds ratio [OR]=4.96, P<0.001), chronic kidney disease (OR=3.62, P<0.001), positive urinary antigen test results (OR=2.57, P=0.001), and advanced age (OR=2.19, P=0.010) were independent predictors for 30-day mortality by logistic regression analysis. Among critically ill patients, chronic kidney disease (OR=4.64, P<0.001), higher APACHE IV score (OR=3.73, P=0.016), and positive urinary antigen test results (OR=2.94, P=0.008) were predictors for 30-day mortality. Logistic regression analysis revealed that chronic kidney disease (OR=3.10, P<0.001) was a risk factor for invasive pneumococcal disease. CONCLUSION: Advanced age, vasopressor use, chronic kidney disease, and positive urinary antigen test results were independent predictors for 30-day mortality in patients with pneumococcal disease.

Impact of Dysnatremia and Dyskalemia on Prognosis in Patients with Aneurysmal Subarachnoid Hemorrhage: A Retrospective Study.

BACKGROUND: Electrolyte disturbance is one of the complications of subarachnoid hemorrhage (SAH) and its prognostic value is not fully understood. The focus of this study is to evaluate the impact of dysnatremia and dyskalemia on functional outcomes in patients with aneurysmal SAH. MATERIALS AND METHODS: Patients with spontaneous aneurysmal SAH who were admitted to our intensive care unit (ICU) between 1st January 2011 and 31st December 2016 were included. Demographic data, biochemical parameters from days 1 to day 11 of ICU admission, disease severity, and clinical outcome were recorded. The prognosis was estimated using the Glasgow outcome scale (GOS) at 3 months after the initial insult. RESULTS: A total of 244 patients were included in this study. There were 139 patients (57.0%) with hyponatremia (Na < 135 mmol/L) while 82 patients (33.6%) had hypernatremia (Na >146 mmol/L). Hyponatremia, hypernatremia, and sodium fluctuation >12 mmol/L were more commonly found in those patients with poor outcome. However, both hypokalemia and hyperkalemia were not shown to have a significant effect on the patient's prognosis. Logistic regression analysis identified the following independent predictors of poor outcome (GOS 1-3 at 3 months): age >55 years old, acute physiology and chronic health evaluation IV (APACHE IV) score >50, World Federation of Neurosurgical Societies (WFNS) grade >3, Fisher grade >2, presence of intracranial hemorrhage (ICH)/intraventricular hemorrhage (IVH), use of mannitol, use of loop diuretic aneurysms, involving posterior circulation, and hypernatremia >146 mmol/L. CONCLUSION: Hypernatremia, but not hyponatremia, in patients with aneurysmal SAH is associated with poor outcome. Both hypokalemia and hyperkalemia were not shown to have a significant effect on the patient's prognosis. Further studies are required to determine whether the treatment of dysnatremia can influence outcomes. CLINICAL SIGNIFICANCE: Dysnatremia and dyskalemia are common in patients with aneurysmal SAH, but only hypernatremia is associated with poor outcome. Further studies are required to determine whether the treatment of dysnatremia can influence outcomes. HOW TO CITE THIS ARTICLE: Tam CWY, Shum HP, Yan WW. Impact of Dysnatremia and Dyskalemia on Prognosis in Patients with Aneurysmal Subarachnoid Hemorrhage: A Retrospective Study. Indian J Crit Care Med 2019;23(12):562-567.

A case of severe empyema with acute respiratory distress syndrome caused by Slackia exigua requiring veno-venous extracorporeal membrane oxygenation.

Slackia exigua (S. exigua) is an obligatory anaerobic coccobacillus under the family of Coriobacteriaceae. It is a rare cause of pyogenic extraoral infections. We report a 58-year-old lady with good past health presented with fulminant community-acquired pneumonia causing acute respiratory distress syndrome caused by S. exigua requiring veno-venous extra-corporeal membrane oxygenation (VV-ECMO). Bacterial identification can be challenging and often require 16 S rRNA and MALDI-TOF MS. The patient was treated with amoxicillin-clavulanic acid according to sensitivity and made significant recovery.

Extracorporeal blood purification for sepsis.

It has been speculated that extracorporeal blood purification therapies might improve the clinical outcome for patients with severe sepsis, with or without acute kidney injury, since the removal of inflammatory mediators and/or bacterial toxins from circulation could modulate the inflammatory responses that result in organ damage. Despite initial enthusiasm based on promising preliminary results, subsequent investigations did not show sustainable survival benefit. We review the principles and development of blood purification techniques for sepsis and septic acute kidney injury.

Risks and benefits of citrate anticoagulation for continuous renal replacement therapy.

Heparin, despite its significant side-effects, is the most commonly used anticoagulant for continuous renal replacement therapy in critical care setting. In recent years, citrate has gained much popularity by improving continuous renal replacement therapy circuit survival and decreasing blood transfusion requirements. However, its complex metabolic consequences warrant modification in the design of the citrate-based continuous renal replacement therapy protocol. With thorough understanding of the therapeutic mechanism of citrate, a simple and practicable protocol can be devised. Citrate-based continuous renal replacement therapy can be safely and widely used in the clinical setting with appropriate clinical staff training.

Outcome of elderly patients who receive intensive care at a regional hospital in Hong Kong.

OBJECTIVE: To evaluate the clinical outcome (180-day mortality) of very elderly critically ill patients (age ≥80 years) and compare with those aged 60 to 79 years. DESIGN: Historical cohort study. SETTING: Regional hospital, Hong Kong. PATIENTS: Patients aged ≥60 years admitted between 1 January 2009 and 31 December 2013 to the Intensive Care Unit of the hospital. RESULTS: Over 5 years, 4226 patients aged ≥60 years were admitted (55.5% total intensive care unit admissions), of whom 32.8% were aged ≥80 years. The proportion of patients aged ≥80 years increased over 5 years. As expected, those aged ≥80 years carried more significant co-morbidities and a higher disease severity compared with those aged 60 to 79 years. They required more mechanical ventilatory support, were less likely to receive renal replacement therapy, and had a higher intensive care unit/hospital/180-day mortality compared with those aged 60 to 79 years. Nonetheless, 71.8% were discharged home and 62.2% survived >180 days following intensive care unit admission. Cox regression analysis revealed that Acute Physiology and Chronic Health Evaluation IV-minus-Age score, emergency admission, intensive care unit admission due to cardiovascular problem, neurosurgical cases, presence of significant co-morbidities (diabetes mellitus, metastatic carcinoma, leukaemia, or myeloma), and requirement for mechanical ventilation independently predicted 180-day mortality. CONCLUSIONS: The proportion of critically ill patients aged ≥80 years increased over a 5-year period. Despite having more significant co-morbidities, greater disease severity, and higher intensive care unit/hospital/180-day mortality rate compared with those aged 60 to 79 years, 71.8% of those ≥80 years could be discharged home and 62.2% survived >180 days following intensive care unit admission. Disease severity, presence of co-morbidities, requirement for mechanical ventilation, emergency cases, and admission diagnosis independently predicted 180-day mortality.

Characteristics of patients readmitted to intensive care unit: a nested case-control study.

OBJECTIVES: To evaluate the pattern of unplanned readmissions to the intensive care unit and identify patients at risk of readmission. DESIGN: Nested case-referent study. SETTING: Tertiary hospital, Hong Kong. PATIENTS: A total of 146 patients with unplanned intensive care unit readmission were compared with 292 control patients who were discharged from the intensive care unit alive and never readmitted. Cases and controls were matched for age, gender, and disease severity. MAIN OUTCOME MEASURES: Patient demographics, initial and pre-discharge clinical parameters, reasons for readmission, and outcomes were studied. RESULTS: During the 30-month study period, the readmission rate was 5.1%. Readmitted patients had significantly higher mortality and longer mean hospital lengths of stay (both P<0.001). Most patients in this cohort (36.3%) were readmitted for a respiratory cause. Based on classification tree analysis, postoperative patients with sepsis (adjusted P=0.043), non-operative septic patients with fluid gain 24 hours pre-discharge (adjusted P=0.013), and non-septic patients with increased sputum quantity on discharge (adjusted P=0.006) were significantly associated with intensive care unit readmission. CONCLUSION: Incomplete resolution of respiratory conditions remained an important reason for potentially preventable intensive care unit readmission. Attention to fluid balance and sputum quantity before intensive care unit discharge might prevent unplanned intensive care unit readmission.

Application of endotoxin and cytokine adsorption haemofilter in septic acute kidney injury due to Gram-negative bacterial infection.

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.

Clostridium perfringens liver abscess with massive haemolysis.

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.

Cast nephropathy with acute renal failure treated with high cut-off haemodialysis in a patient with multiple myeloma.

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.

Star fruit intoxication successfully treated by charcoal haemoperfusion and intensive haemofiltration.

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.

Clinical predictors and outcomes of Klebsiella pneumoniae bacteraemia in a regional hospital in Hong Kong.

BACKGROUND: Klebsiella pneumoniae (KP) infection is associated with high morbidity and mortality. Multidrug resistance, especially extended-spectrum ß-lactamase (ESBL) production, in KP is endemic worldwide. AIM: To evaluate the clinical characteristics and outcomes of patients with KP bacteraemia in critical care and general ward settings. METHODS: Adult patients admitted to a regional hospital in Hong Kong from January 1st, 2009 to June 30th, 2016 (7.5 years) with KP bacteraemia were included. Demographics, clinical features, microbiological characteristics, and outcomes were analysed. FINDINGS: Among 853 patients, 178 (20.9%) required critical care and 176 (20.6%) died within 30 days of hospital admission. Thirty-day survivors were younger (P<0.001), had milder disease (defined by Sequential Organ Failure Assessment score) (P<0.001), presented with hepatobiliary sepsis (P<0.001) or urosepsis (P<0.001), less septic shock (P=0.013), fewer invasive organ supports (P<0.001), and had appropriate empirical antibiotics (P<0.001). Cox regression analysis showed that respiratory tract infection (hazard ratio: 2.99; 95% confidence interval: 2.061-4.337; P≤0.001), gastrointestinal tract infection (excluding hepatobiliary system) (2.763; 1.761-4.337; P≤0.001), mechanical ventilation (2.202; 1.506-3.221; P≤0.001), medical case (1.830; 1.253-2.672; P=0.002), inappropriate empirical antibiotics (1.716; 1.267-2.324; P≤0.001), female (1.699; 1.251-2.307; P<0.001), age >65 years (1.692; 1.160-2.467; P=0.006), and presence of solid tumour (1.457; 1.056-2.009; P=0.022) were independent risk factors for 30-day mortality. Unexpectedly, diabetes mellitus was associated with better 30-day survival (P=0.002). A total of 102 patients (12.0%) had infections with ESBL-producing strains, which were not associated with higher 30-day mortality. CONCLUSION: KP bacteraemia is associated with high 30-day mortality. Site of infection, patients' comorbidities and appropriate use of empirical antibiotic are important predictors of patients' outcomes.