A user evaluation of speech/phrase recognition software in critically ill patients: a DECIDE-AI feasibility study.

OBJECTIVES: Evaluating effectiveness of speech/phrase recognition software in critically ill patients with speech impairments. DESIGN: Prospective study. SETTING: Tertiary hospital critical care unit in the northwest of England. PARTICIPANTS: 14 patients with tracheostomies, 3 female and 11 male. MAIN OUTCOME MEASURES: Evaluation of dynamic time warping (DTW) and deep neural networks (DNN) methods in a speech/phrase recognition application. Using speech/phrase recognition app for voice impaired (SRAVI), patients attempted mouthing various supported phrases with recordings evaluated by both DNN and DTW processing methods. Then, a trio of potential recognition phrases was displayed on the screen, ranked from first to third in order of likelihood. RESULTS: A total of 616 patient recordings were taken with 516 phrase identifiable recordings. The overall results revealed a total recognition accuracy across all three ranks of 86% using the DNN method. The rank 1 recognition accuracy of the DNN method was 75%. The DTW method had a total recognition accuracy of 74%, with a rank 1 accuracy of 48%. CONCLUSION: This feasibility evaluation of a novel speech/phrase recognition app using SRAVI demonstrated a good correlation between spoken phrases and app recognition. This suggests that speech/phrase recognition technology could be a therapeutic option to bridge the gap in communication in critically ill patients. WHAT IS ALREADY KNOWN ABOUT THIS TOPIC: Communication can be attempted using visual charts, eye gaze boards, alphabet boards, speech/phrase reading, gestures and speaking valves in critically ill patients with speech impairments. WHAT THIS STUDY ADDS: Deep neural networks and dynamic time warping methods can be used to analyse lip movements and identify intended phrases. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE AND POLICY: Our study shows that speech/phrase recognition software has a role to play in bridging the communication gap in speech impairment.

Validation of a shortened MR imaging protocol for pediatric spinal pathology.

OBJECTIVE: Conventional pediatric spine MRI protocols have multiple sequences resulting in long acquisition times. Sedation is consequently required. This study evaluates the diagnostic capability of a limited MRI spine protocol for selected common pediatric indications. METHODS: Spine MRIs at CHEO between 2017 and 2020 were reviewed across pediatric patients younger than four years old. Two blinded neuroradiologists reviewed limited scan sequences, and results were independently compared to previously reported findings from the complete imaging series. T2 sagittal sequences from the craniocervical junction to sacrum and T1 axial sequence of the lumbar spine constitute the short protocol, with the outcomes of interest being cerebellar ectopia, syrinx, level of conus, filum < 2 mm, fatty filum, and spinal dysraphism. RESULTS: A total of 105 studies were evaluated in 54 male and 51 female patients (mean age 19.2 months). The average combined scan time of the limited sequences was 15 min compared to 35 min for conventional protocols (delta = 20 min). The average percent agreement between full and limited sequences was > 95% in all but identifying a filum < 2 mm, where the percent agreement was 87%. Using limited MR sequences had high sensitivity (> 0.91) and specificity (> 0.99) for the detection of cerebellar ectopia, syrinx, fatty filum, and spinal dysraphism. CONCLUSION: This study demonstrates that selected spinal imaging sequences allow for consistent and accurate diagnosis of specific clinical conditions. A limited spine imaging protocol has potential as a screening test to reduce the need for full-sequence MRI scans. Further work is needed to determine utility of selected imaging for other clinical indications.

Sugar or salt ("SOS"): A protocol for a UK multicentre randomised trial of mannitol and hypertonic saline in severe traumatic brain injury and intracranial hypertension.

Hyperosmolar solutions are widely used to treat raised intracranial pressure following severe traumatic brain injury. Although mannitol has historically been the most frequently administered, hypertonic saline solutions are increasingly being used. However, definitive evidence regarding their comparative effectiveness is lacking. The Sugar or Salt Trial is a UK randomised, allocation concealed open label multicentre pragmatic trial designed to determine the clinical and cost-effectiveness of hypertonic saline compared with mannitol in the management of patients with severe traumatic brain injury. Patients requiring intensive care unit admission and intracranial pressure monitoring post-traumatic brain injury will be allocated at random to receive equi-osmolar boluses of either mannitol or hypertonic saline following failure of routine first-line measures to control intracranial pressure. The primary outcome for the study will be the Extended Glasgow Outcome Scale assessed at six months after randomisation. Results will inform current clinical practice in the routine use of hyperosmolar therapy as well as assess the impact of potential side effects. Pre-planned longer term clinical and cost effectiveness analyses will further inform the use of these treatments.

Mesenchymal stem/stromal cell-based therapies for severe viral pneumonia: therapeutic potential and challenges.

Severe viral pneumonia is a significant cause of morbidity and mortality globally, whether due to outbreaks of endemic viruses, periodic viral epidemics, or the rarer but devastating global viral pandemics. While limited anti-viral therapies exist, there is a paucity of direct therapies to directly attenuate viral pneumonia-induced lung injury, and management therefore remains largely supportive. Mesenchymal stromal/stem cells (MSCs) are receiving considerable attention as a cytotherapeutic for viral pneumonia. Several properties of MSCs position them as a promising therapeutic strategy for viral pneumonia-induced lung injury as demonstrated in pre-clinical studies in relevant models. More recently, early phase clinical studies have demonstrated a reassuring safety profile of these cells. These investigations have taken on an added importance and urgency during the COVID-19 pandemic, with multiple trials in progress across the globe. In parallel with clinical translation, strategies are being investigated to enhance the therapeutic potential of these cells in vivo, with different MSC tissue sources, specific cellular products including cell-free options, and strategies to 'licence' or 'pre-activate' these cells, all being explored. This review will assess the therapeutic potential of MSC-based therapies for severe viral pneumonia. It will describe the aetiology and epidemiology of severe viral pneumonia, describe current therapeutic approaches, and examine the data suggesting therapeutic potential of MSCs for severe viral pneumonia in pre-clinical and clinical studies. The challenges and opportunities for MSC-based therapies will then be considered.

Development of a Core Outcome Set for studies evaluating the effects of anaesthesia on perioperative morbidity and mortality following hip fracture surgery.

BACKGROUND: Perioperative studies of patients following hip fracture have large heterogeneity within their reported outcomes. This study aimed to develop a core outcome set for use in perioperative studies comparing the types of anaesthesia for hip fracture surgery. METHODS: The consensus process consisted of a systematic review of the literature, three rounds of a Delphi survey, two consensus webinars, and face-to-face patient meetings. RESULTS: The Delphi participants represented nine stakeholder groups. The numbers of participants completing Rounds 1-3 were 242, 186, and 169, respectively. Seventeen outcomes that met the predefined consensus criteria were considered at two consensus meetings. A final set of 10 core outcomes was agreed: mortality, time from injury to surgery, acute coronary syndrome, hypotension, acute kidney injury, delirium, pneumonia, orthogeriatric input, being out of bed at day 1, and pain. CONCLUSIONS: We generated a consensus-based set of core outcomes recommended for use in all perioperative trials evaluating the effects of anaesthesia for hip fracture surgery. An important next step is developing consensus-based consistency on how they should be measured. CLINICAL TRIAL REGISTRATION: http://www.comet-initiative.org/studies/details/757.

Perioperative outcomes in the context of mode of anaesthesia for patients undergoing hip fracture surgery: systematic review and meta-analysis.

BACKGROUND: Previous meta-analyses on the anaesthetic management of patients undergoing surgery for hip fracture have focused on randomized trials. Furthermore, heterogeneity in outcome reporting across the studies has made it difficult to inform best practice guidelines for patient care. METHODS: This systematic review examined how perioperative outcomes were reported and defined in the context of comparing modes of anaesthesia for hip fracture surgery. Outcomes were included from randomised and non-randomised studies published between January 2000 and July 2017. Meta-analyses were performed for regional versus general anaesthesia, with sensitivity analyses performed for spinal versus general anaesthesia. RESULTS: By including data from 15 large observational studies in this meta-analysis, we have increased the number of patients for whom outcomes were assessed from approximately 3000 to 202 000. There was no significant difference in 30-day mortality (OR 1.02; 95% CI 0.96, 1.07, I2 31%; n=200 616), prevalence of pneumonia (OR 1.07; 95% CI 0.94, 1.23, I2 34%; n=65 011), acute myocardial infarction (OR 0.96; 95% CI 0.88, 1.04, I2 0%, n=64 904), delirium (OR 1.07; 95% CI 0.72, 1.58, I2 93%, n=19 923), or renal failure (OR 0.94; 95% CI 0.54, 1.64, I2 0%, n=27 873) for regional compared with general anaesthesia [corrected]. There was a small statistically significant difference for length of stay (standardized mean difference -0.03; 95% CI -0.05, -0.02; I2 0%; n=78 711) favouring regional anaesthesia, which is unlikely to be clinically significant. Sensitivity analyses for the same outcomes examining spinal only vs general anaesthesia showed minor statistical significance for length of stay favouring spinal. We also present data highlighting the scale of the inconsistencies in reported outcomes across 32 studies, making evaluation in a standardized manner very difficult. As an example, mortality was reported in nine different ways throughout the studies. CONCLUSIONS: We highlight the need for agreement on outcome definitions and for a minimum core outcome set to be measured and reported in hip fracture studies. This would strengthen the evidence-based approach to delivering optimal care.

pRotective vEntilation with veno-venouS lung assisT in respiratory failure: A protocol for a multicentre randomised controlled trial of extracorporeal carbon dioxide removal in patients with acute hypoxaemic respiratory failure.

One of the few interventions to demonstrate improved outcomes for acute hypoxaemic respiratory failure is reducing tidal volumes when using mechanical ventilation, often termed lung protective ventilation. Veno-venous extracorporeal carbon dioxide removal (vv-ECCO2R) can facilitate reducing tidal volumes. pRotective vEntilation with veno-venouS lung assisT (REST) is a randomised, allocation concealed, controlled, open, multicentre pragmatic trial to determine the clinical and cost-effectiveness of lower tidal volume mechanical ventilation facilitated by vv-ECCO2R in patients with acute hypoxaemic respiratory failure. Patients requiring intubation and mechanical ventilation for acute hypoxaemic respiratory failure will be randomly allocated to receive either vv-ECCO2R and lower tidal volume mechanical ventilation or standard care with stratification by recruitment centre. There is a need for a large randomised controlled trial to establish whether vv-ECCO2R in acute hypoxaemic respiratory failure can allow the use of a more protective lung ventilation strategy and is associated with improved patient outcomes.

Simvastatin for patients with acute respiratory distress syndrome: long-term outcomes and cost-effectiveness from a randomised controlled trial.

BACKGROUND: Simvastatin therapy for patients with acute respiratory distress syndrome (ARDS) has been shown to be safe and associated with minimal adverse effects, but it does not improve clinical outcomes. The aim of this research was to report on mortality and cost-effectiveness of simvastatin in patients with ARDS at 12 months. METHODS: This was a cost-utility analysis alongside a multicentre, double-blind, randomised controlled trial carried out in the UK and Ireland. Five hundred and forty intubated and mechanically ventilated patients with ARDS were randomly assigned (1:1) to receive once-daily simvastatin (at a dose of 80 mg) or identical placebo tablets enterally for up to 28 days. RESULTS: Mortality was lower in the simvastatin group (31.8%, 95% confidence interval (CI) 26.1-37.5) compared to the placebo group (37.3%, 95% CI 31.6-43.0) at 12 months, although this was not significant. Simvastatin was associated with statistically significant quality-adjusted life year (QALY) gain (incremental QALYs 0.064, 95% CI 0.002-0.127) compared to placebo. Simvastatin was also less costly (incremental total costs -£3601, 95% CI -8061 to 859). At a willingness-to-pay threshold of £20,000 per QALY, the probability of simvastatin being cost-effective was 99%. Sensitivity analyses indicated that the results were robust to changes in methodological assumptions with the probability of cost-effectiveness never dropping below 90%. CONCLUSION: Simvastatin was found to be cost-effective for the treatment of ARDS, being associated with both a significant QALY gain and a cost saving. There was no significant reduction in mortality at 12 months, TRIAL REGISTRATION: ISRCTN, 88244364. Registered 26 November 2010.

Individual patient data analysis of tidal volumes used in three large randomized control trials involving patients with acute respiratory distress syndrome.

BACKGROUND.: The acute respiratory distress syndrome (ARDS) is a condition with a high mortality and morbidity. Mechanical ventilation prevents immediate mortality but may further damage patients' lungs. Low tidal volume lung-protective strategies have been shown to increase survival by reducing this iatrogenic damage. Current guidelines recommend tidal volumes of 6-8 ml kg -1 of predicted body weight. We used data from three large randomized controlled trials of treatments for ARDS to determine compliance with these recommendations. METHODS.: We used the tidal volume recorded at randomization for all patients in the OSCAR, HARP-2, and BALTI-2 studies. In addition, we used the ventilation data for control arm patients in OSCAR and all patients in HARP-2 at days 1 and 7 after randomization. RESULTS.: The three trials enrolled 1660 patients, with tidal volume data available at least at one time point in 1412 patients. Compliance with the 6-8 ml kg -1 recommendation for tidal volume ranged from 20 to 39% of patients across all time points in all three trials. CONCLUSION.: Poor compliance with the guidelines for tidal volume in patients with ARDS has been demonstrated before in case series, but not in clinical trials where the patient population is specifically selected against standard ARDS diagnostic criteria and the investigators were encouraged to use low tidal volumes. This study may indicate a need to improve implementation and compliance with protective lung ventilation.

Aspirin reduces lipopolysaccharide-induced pulmonary inflammation in human models of ARDS.

RATIONALE: Platelets play an active role in the pathogenesis of acute respiratory distress syndrome (ARDS). Animal and observational studies have shown aspirin's antiplatelet and immunomodulatory effects may be beneficial in ARDS. OBJECTIVE: To test the hypothesis that aspirin reduces inflammation in clinically relevant human models that recapitulate pathophysiological mechanisms implicated in the development of ARDS. METHODS: Healthy volunteers were randomised to receive placebo or aspirin 75  or 1200 mg (1:1:1) for seven days prior to lipopolysaccharide (LPS) inhalation, in a double-blind, placebo-controlled, allocation-concealed study. Bronchoalveolar lavage (BAL) was performed 6 hours after inhaling 50 µg of LPS. The primary outcome measure was BAL IL-8. Secondary outcome measures included markers of alveolar inflammation (BAL neutrophils, cytokines, neutrophil proteases), alveolar epithelial cell injury, systemic inflammation (neutrophils and plasma C-reactive protein (CRP)) and platelet activation (thromboxane B2, TXB2). Human lungs, perfused and ventilated ex vivo (EVLP) were randomised to placebo or 24 mg aspirin and injured with LPS. BAL was carried out 4 hours later. Inflammation was assessed by BAL differential cell counts and histological changes. RESULTS: In the healthy volunteer (n=33) model, data for the aspirin groups were combined. Aspirin did not reduce BAL IL-8. However, aspirin reduced pulmonary neutrophilia and tissue damaging neutrophil proteases (Matrix Metalloproteinase (MMP)-8/-9), reduced BAL concentrations of tumour necrosis factor α and reduced systemic and pulmonary TXB2. There was no difference between high-dose and low-dose aspirin. In the EVLP model, aspirin reduced BAL neutrophilia and alveolar injury as measured by histological damage. CONCLUSIONS: These are the first prospective human data indicating that aspirin inhibits pulmonary neutrophilic inflammation, at both low and high doses. Further clinical studies are indicated to assess the role of aspirin in the prevention and treatment of ARDS. TRIAL REGISTRATION NUMBER: NCT01659307 Results.

The impact of the acute respiratory distress syndrome on outcome after oesophagectomy.

BACKGROUND: The Acute Respiratory Distress Syndrome (ARDS) is a serious complication of major surgery and consumes substantial healthcare resources. Oesophagectomy is associated with high rates of ARDS. The aim of this study was to characterize patients and identify risk factors for developing ARDS after oesophagectomy. METHODS: A secondary analysis of data from 331 patients gathered during the Beta Agonists Lung Injury Prevention Trial was undertaken. Characteristics and outcomes of patients with early (first 72 h postoperatively) and late (after 72 h) ARDS were determined. Linear and multivariate regression analysis was used to study the differences between early and late ARDS and identify risk factors. RESULTS: ARDS was associated with more non-respiratory organ failure (early 44.1%, late 75.0%, no ARDS 27.6% P<0.001), longer ICU stay (mean early 12.1, late 20.2, no ARDS 7.3 days P<0.001) and longer hospital stay (mean early 18.1, late 24.5, no ARDS 14.2 days P<0.001) but no difference in mortality or quality of life. Older patients (OR 1.06 (1.00 to 1.13), P=0.045) and those with mid-oesophageal tumours (OR 7.48 (1.62-34.5), P=0.010) had a higher risk for ARDS. CONCLUSIONS: Early and late ARDS after oesophagectomy increases intensive care and hospital length of stay. Given the high incidence of ARDS, cohorts of patients undergoing oesophagectomy may be useful as models for studies investigating ARDS prevention and treatment. Further investigations aimed at reducing perioperative ARDS are warranted.

Early feeding after free flap reconstruction for oral cancer.

Traditionally, after resection of oral cancer and free flap reconstruction, patients are given nothing by mouth for between 6 and 12 days to allow adequate time for healing and to reduce the risk of dehiscence. To assess the impact of early oral feeding after operation we retrospectively reviewed 10 consecutive patients who had had surgical resection and free flap reconstruction for oral cancer. Details recorded included histopathological findings, stage and site of the primary tumour, and type of reconstruction. Data on the duration of tracheostomy, commencement of clear fluids and diet, complications, and duration of hospital stay, were also recorded. Half of the patients were able to tolerate clear fluids orally by the first postoperatively day and the remaining half by the second. By the fourth day, 8 could manage a pureed diet. There were no complications. A mean duration of hospital stay of 11 days (range 5-16) compared favourably with previous studies. Early oral feeding was not associated with any increased morbidity or adverse outcome. A shorter hospital stay may favour the adoption of an improved recovery programme as seen in other surgical specialties.

Statin therapy in critically-ill patients with severe sepsis: a review and meta-analysis of randomized clinical trials.

UNLABELLED: While statins are indicated to reduce blood cholesterol levels, they also have anti-inflammatory and immunomodulatory effects. Several observational cohort studies suggested that statins may improve survival and reduce complications in patients with sepsis. Recent randomized controlled studies in critically ill patients have been conducted and published. In this paper we present a meta-analysis of these randomized trials. METHODS: An electronic article search through PubMed was performed. Only randomized controlled trials including critically ill adult patients with severe sepsis were retained. A meta-analysis was performed as detailed in text below. Overall analysis including 1818 patients total from 4 studies showed that there was no difference in 60-day mortality between statins (223/903) and placebo (233/899) [risk ratio, 0.930; 95% CI, 0.722 to 1.198]. Similarly, no difference in 28-day mortality was observed between groups (statins 191/907, placebo 199/911; risk ratio 0.953; 95% CI, 0.715 to 1.271). The results of this meta-analysis confirm that the use of statin therapy should not be recommended in the management of severe sepsis in critically ill patients. Statins should be continued with caution and only if necessary, as one study reported that the statin group had a higher rate of hepatic and renal failure.

Mesenchymal stromal cells for treatment of the acute respiratory distress syndrome: The beginning of the story.

In spite of decades of research, the acute respiratory distress syndrome (ARDS) continues to have an unacceptably high mortality and morbidity. Mesenchymal stromal cells (MSCs) present a promising candidate for the treatment of this condition and have demonstrated benefit in preclinical models. MSCs, which are a topic of growing interest in many inflammatory disorders, have already progressed to early phase clinical trials in ARDS. While a number of their mechanisms of effect have been elucidated, a better understanding of the complex actions of these cells may pave the way for MSC modifications, which might enable more effective translation into clinical practice.

Clinical grade allogeneic human mesenchymal stem cells restore alveolar fluid clearance in human lungs rejected for transplantation.

The lack of suitable donors for all solid-organ transplant programs is exacerbated in lung transplantation by the low utilization of potential donor lungs, due primarily to donor lung injury and dysfunction, including pulmonary edema. The current studies were designed to determine if intravenous clinical-grade human mesenchymal stem (stromal) cells (hMSCs) would be effective in restoring alveolar fluid clearance (AFC) in the human ex vivo lung perfusion model, using lungs that had been deemed unsuitable for transplantation and had been subjected to prolonged ischemic time. The human lungs were perfused with 5% albumin in a balanced electrolyte solution and oxygenated with continuous positive airway pressure. Baseline AFC was measured in the control lobe and if AFC was impaired (defined as <10%/h), the lungs received either hMSC (5 × 10(6) cells) added to the perfusate or perfusion only as a control. AFC was measured in a different lung lobe at 4 h. Intravenous hMSC restored AFC in the injured lungs to a normal level. In contrast, perfusion only did not increase AFC. This positive effect on AFC was reduced by intrabronchial administration of a neutralizing antibody to keratinocyte growth factor (KGF). Thus, intravenous allogeneic hMSCs are effective in restoring the capacity of the alveolar epithelium to remove alveolar fluid at a normal rate, suggesting that this therapy may be effective in enhancing the resolution of pulmonary edema in human lungs deemed clinically unsuitable for transplantation.

Beta-Agonist Lung injury TrIal-2 (BALTI-2): a multicentre, randomised, double-blind, placebo-controlled trial and economic evaluation of intravenous infusion of salbutamol versus placebo in patients with acute respiratory distress syndrome.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a major cause of mortality in intensive care patients and lacks effective treatments. A previous randomised controlled Phase II trial suggested that an intravenous (i.v.) infusion of salbutamol may be beneficial, as it reduced extravascular lung water and plateau airway pressure. The Beta-Agonist Lung injury TrIal-2 (BALTI-2) was initiated to evaluate the effects of this intervention on mortality in patients with ARDS. OBJECTIVES: To evaluate whether or not, in patients with ARDS, an i.v. infusion of salbutamol given at 15 µg/kg ideal body weight (IBW)/hour for up to 7 days, compared with a placebo (0.9% sodium chloride) infusion, reduces 28-day all-cause mortality and other clinical outcomes. To evaluate salbutamol's clinical effectiveness and its cost-effectiveness in subgroups of patients. DESIGN: A multicentre, randomised, placebo-controlled trial. SETTING: Forty-six intensive care units (ICUs) in the UK. PARTICIPANTS: Patients were eligible if they (1) were intubated and mechanically ventilated patients in participating ICUs; (2) were within 72 hours of onset of ARDS; (3) fulfilled American-European Consensus Conference definition for ARDS {acute-onset, severe hypoxaemic respiratory failure [partial pressure of oxygen in arterial blood/fraction of inspired oxygen ≤ 26.7 kPa (200 mmHg)] and bilateral infiltrates on the chest radiograph in the absence of clinical evidence of left atrial hypertension}; and (4) were aged ≥ 16 years. INTERVENTIONS: Intravenous infusion of salbutamol (15 µg/kg IBW/hour) or placebo (0.9% saline) for up to 7 days. MAIN OUTCOME MEASURES: All-cause mortality 28 days after randomisation, mortality at (first) discharge from ICU, mortality at (first) discharge from hospital, number of ventilator-free days, number of organ failure-free days, mortality at 12 months post randomisation, side effects (tachycardia/new arrhythmia/lactic acidosis) sufficient to stop treatment with trial drug, health-related quality of life (European Quality of Life-5 Dimensions and Short Form questionnaire-12 items at 6 and 12 months after randomisation), length of stay in critical care unit and length of stay in hospital. RESULTS: Forty-six ICUs recruited patients to the trial. A total of 326 patients were randomised; 162 were allocated to salbutamol and 164 to placebo. One patient in each group withdrew consent. Recruitment was stopped after the second interim analysis because of safety concerns. Salbutamol increased 28-day mortality: 55 (34%) of 161 patients died in the salbutamol group compared with 38 (23%) of 163 in the placebo group (risk ratio 1.47, 95% confidence interval 1.03 to 2.08). CONCLUSIONS: Treatment with i.v. salbutamol early in the course of ARDS was poorly tolerated, is unlikely to be beneficial and could worsen outcomes. Further trials of ß-agonists in patients with ARDS are unlikely to be conducted. Some questions remain, such as whether or not there may be benefit at a different dose or in specific populations, but any studies investigating these would require a very strong rationale. TRIAL REGISTRATION: Current Controlled Trials ISRCTN38366450. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Combined dysfunctions of immune cells predict nosocomial infection in critically ill patients.

BACKGROUND: Nosocomial infection occurs commonly in intensive care units (ICUs). Although critical illness is associated with immune activation, the prevalence of nosocomial infections suggests concomitant immune suppression. This study examined the temporal occurrence of immune dysfunction across three immune cell types, and their relationship with the development of nosocomial infection. METHODS: A prospective observational cohort study was undertaken in a teaching hospital general ICU. Critically ill patients were recruited and underwent serial examination of immune status, namely percentage regulatory T-cells (Tregs), monocyte deactivation (by expression) and neutrophil dysfunction (by CD88 expression). The occurrence of nosocomial infection was determined using pre-defined, objective criteria. RESULTS: Ninety-six patients were recruited, of whom 95 had data available for analysis. Relative to healthy controls, percentage Tregs were elevated 6-10 days after admission, while monocyte HLA-DR and neutrophil CD88 showed broader depression across time points measured. Thirty-three patients (35%) developed nosocomial infection, and patients developing nosocomial infection showed significantly greater immune dysfunction by the measures used. Tregs and neutrophil dysfunction remained significantly predictive of infection in a Cox hazards model correcting for time effects and clinical confounders {hazard ratio (HR) 2.4 [95% confidence interval (CI) 1.1-5.4] and 6.9 (95% CI 1.6-30), respectively, P=0.001}. Cumulative immune dysfunction resulted in a progressive risk of infection, rising from no cases in patients with no dysfunction to 75% of patients with dysfunction of all three cell types (P=0.0004). CONCLUSIONS: Dysfunctions of T-cells, monocytes, and neutrophils predict acquisition of nosocomial infection, and combine additively to stratify risk of nosocomial infection in the critically ill.