Outcomes associated with a variable rate insulin infusion diabetic ketoacidosis protocol

AIMS

To relate adverse events with glucose correction rates in diabetic ketoacidosis (DKA) using variable rate intravenous insulin-infusions (VRIII).

METHODS

Retrospective, observational study in adults with DKA who received insulin infusions between 2012 and 2017 at St Vincent's Hospital, Melbourne. Early correction of hyperglycaemia (<10 mmol/L) was evaluated for association with hypoglycaemia (<4.0 mmol/L), hypokalaemia (potassium <3.3 mmol/L) and clinical outcomes via regression analysis.

RESULTS

The study involved 97 patients, with 93 % having type 1 diabetes. The mean age was 38 years, 47 % were women and 35 % were admitted to intensive care. Hypoglycaemia rates during 12 and 24 h of treatment were 6.2 % and 8.2 %, respectively with 58 % of patients recording their first BGL <10 mmol/L within 12 h and 88 % within 24 h. Ketone clearance time averaged at 15.6 h. Hyperglycaemia correction rates to <10 mmol/L were not different in those with/without hypoglycaemia at 12/24 h, in multivariate analysis including admission BGL. Hypokalaemia occurred in 40.2 % of patients and was associated with lower pH but not BGL correction rates.

CONCLUSION

The VRIII protocol achieved early hyperglycaemia correction and ketoacidosis reversal with low hypoglycaemia risk. However, high hypokalaemia rates suggest the need for aggressive potassium replacement, especially in markedly acidotic patients.

Modelling of intensive care unit (ICU) length of stay as a quality measure: a problematic exercise

BACKGROUND

Intensive care unit (ICU) length of stay (LOS) and the risk adjusted equivalent (RALOS) have been used as quality metrics. The latter measures entail either ratio or difference formulations or ICU random effects (RE), which have not been previously compared.

METHODS

From calendar year 2016 data of an adult ICU registry-database (Australia & New Zealand Intensive Care Society (ANZICS) CORE), LOS predictive models were established using linear (LMM) and generalised linear (GLMM) mixed models. Model fixed effects quality-metric formulations were estimated as RALOSR for LMM (geometric mean derived from log(ICU LOS)) and GLMM (day) and observed minus expected ICU LOS (OMELOS from GLMM). Metric confidence intervals (95%CI) were estimated by bootstrapping; random effects (RE) were predicted for LMM and GLMM. Forest-plot displays of ranked quality-metric point-estimates (95%CI) were generated for ICU hospital classifications (metropolitan, private, rural/regional, and tertiary). Robust rank confidence sets (point estimate and 95%CI), both marginal (pertaining to a singular ICU) and simultaneous (pertaining to all ICU differences), were established.

RESULTS

The ICU cohort was of 94,361 patients from 125 ICUs (metropolitan 16.9%, private 32.8%, rural/regional 6.4%, tertiary 43.8%). Age (mean, SD) was 61.7 (17.5) years; 58.3% were male; APACHE III severity-of-illness score 54.6 (25.7); ICU annual patient volume 1192 (702) and ICU LOS 3.2 (4.9). There was no concordance of ICU ranked model predictions, GLMM versus LMM, nor for the quality metrics used, RALOSR, OMELOS and site-specific RE for each of the ICU hospital classifications. Furthermore, there was no concordance between ICU ranking confidence sets, marginal and simultaneous for models or quality metrics.

CONCLUSIONS

Inference regarding adjusted ICU LOS was dependent upon the statistical estimator and the quality index used to quantify any LOS differences across ICUs. That is, there was no "one best model"; thus, ICU "performance" is determined by model choice and any rankings thereupon should be circumspect.

Assessment of a Non-Invasive Brain Pulse Monitor to Measure Intra-Cranial Pressure Following Acute Brain Injury

Background

Intracranial pressure (ICP) monitoring requires placing a hole in the skull through which an invasive pressure monitor is inserted into the brain. This approach has risks for the patient and is expensive. We have developed a non-invasive brain pulse monitor that uses red light to detect a photoplethysmographic (PPG) signal arising from the blood vessels on the brain's cortical surface. The brain PPG and the invasive ICP waveform share morphological features which may allow measurement of the intracranial pressure.

Methods

We enrolled critically ill patients with an acute brain injury with invasive ICP monitoring to assess the new monitor. A total of 24 simultaneous invasive ICP and brain pulse monitor PPG measurements were undertaken in 12 patients over a range of ICP levels.

Results

The waveform morphologies were similar for the invasive ICP and brain pulse monitor PPG approach. Both methods demonstrated a progressive increase in the amplitude of P2 relative to P1 with increasing ICP levels. An automated algorithm was developed to assess the PPG morphological features in relation to the ICP level. A correlation was demonstrated between the brain pulse waveform morphology and ICP levels, R²=0.66, P < 0.001.

Conclusion

The brain pulse monitor's PPG waveform demonstrated morphological features were similar to the invasive ICP waveform over a range of ICP levels, these features may provide a method to measure ICP levels.

Trial Registration

ACTRN12620000828921.

Can nebulised HepArin Reduce morTality and time to Extubation in Patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT): Protocol and Statistical Analysis Plan for an investigator-initiated international meta-trial of prospective randomised clinical studies

There is significant interest in the potential for nebulised unfractionated heparin (UFH) as a novel therapy for patients with COVID-19 induced acute hypoxaemic respiratory failure requiring invasive ventilation. The scientific and biological rationale for nebulised heparin stems from the evidence for extensive activation of coagulation resulting in pulmonary microvascular thrombosis in COVID-19 pneumonia. Nebulised delivery of heparin to the lung may limit alveolar fibrin deposition and thereby limit progression of lung injury. Importantly, laboratory studies show that heparin can directly inactivate the SARS-CoV-2 virus, thereby prevent its entry into and infection of mammalian cells. UFH has additional anti-inflammatory and mucolytic properties that may be useful in this context. METHODS AND INTERVENTION: The Can nebulised HepArin Reduce morTality and time to Extubation in Patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT) is a collaborative prospective individual patient data analysis of on-going randomised controlled clinical trials across several countries in 5 continents, examining the effects of inhaled heparin in patients with COVID-19 requiring invasive ventilation on various endpoints. Each constituent study will randomise patients with COVID-19 induced respiratory failure requiring invasive ventilation. Patients are randomised to receive nebulised heparin or standard care (open label studies) or placebo (blinded placebo-controlled studies) while under invasive ventilation. Each participating study collect a pre-defined minimum dataset. The primary outcome for the meta-trial is the number of ventilator-free days up to day 28 day, defined as days alive and free from invasive ventilation. ETHICS AND DISSEMINATION: The meta-trial is registered at ClinicalTrials.gov ID NCT04545541. Each contributing study is individually registered and has received approval of the relevant ethics committee or institutional review board. Results of this study will be shared with the WHO, published in scientific journals, and presented at scientific meetings.

Hospital-acquired complications: the relative importance of hospital- and patient-related factors

OBJECTIVE

To quantify the prevalence of hospital-acquired complications; to determine the relative influence of patient- and hospital-related factors on complication rates.

DESIGN, PARTICIPANTS

Retrospective analysis of administrative data (Integrated South Australian Activity Collection; Victorian Admitted Episodes Dataset) for multiple-day acute care episodes for adults in public hospitals.

SETTING

Thirty-eight major public hospitals in South Australia and Victoria, 2015-2018.

MAIN OUTCOME MEASURES

Hospital-acquired complication rates, overall and by complication class, by hospital and hospital type (tertiary referral, major metropolitan service, major regional service); variance in rates (intra-class correlation coefficient, ICC) at the patient, hospital, and hospital type levels as surrogate measures of their influence on rates.

RESULTS

Of 1 558 978 public hospital episodes (10 029 918 bed-days), 151 486 included a total of 214 286 hospital-acquired complications (9.72 [95% CI, 9.67-9.77] events per 100 episodes; 2.14 [95% CI, 2.13-2.15] events per 100 bed-days). Complication rates were highest in tertiary referral hospitals (12.7 [95% CI, 12.6-12.8] events per 100 episodes) and for episodes including intensive care components (37.1 [95% CI, 36.7-37.4] events per 100 episodes). For all complication classes, inter-hospital variation was determined more by patient factors (overall ICC, 0.55; 95% CI, 0.53-0.57) than by hospital factors (ICC, 0.04; 95% CI, 0.02-0.07) or hospital type (ICC, 0.01; 95% CI, 0.001-0.03).

CONCLUSIONS

Hospital-acquired complications were recorded for 9.7% of hospital episodes, but patient-related factors played a greater role in determining their prevalence than the treating hospital.

Hospital-acquired complications in critically ill patients

Background: The national hospital-acquired complications (HAC) system has been promoted as a method to identify health care errors that may be mitigated by clinical interventions. Objectives: To quantify the rate of HAC in multiday stay adults admitted to major hospitals. Design: Retrospective observational analysis of 5-year (July 2014 - June 2019) administrative dataset abstracted from medical records. Setting: All 47 hospitals with on-site intensive care units (ICUs) in the State of Victoria. Participants: All adults (aged ≥ 18 years) stratified into planned or unplanned, surgical or medical, ICU or other ward, and by hospital peer group (tertiary referral, metropolitan, regional). Main outcome measures: HAC rates in ICU compared with ward, and mixed-effects regression estimates of the association between HAC and i) risk of clinical deterioration, and ii) admission hospital site (intraclass correlation coefficient [ICC] > 0.3). Results: 211 120 adult ICU separations with mean hospital mortality of 7.3% (95% CI, 7.2-7.4%) reported 110 132 (42.6%) HAC events (commonly, delirium, infection, arrhythmia and respiratory failure) in 62 945 records (29.8%). Higher HAC rates were reported in elective (cardiac [50.3%] and non-cardiac [40.6%]) surgical subgroups compared with emergency medical subgroup (23.9%), and in tertiary (35.4%) compared with non-tertiary (22.7%) hospitals. HAC was strongly associated with on-admission patient characteristics (P < 0.001), but was weakly associated with hospital site (ICC, 0.08; 95% CI, 0.05-0.11). Conclusions: Critically ill patients have a high burden of HAC events, which appear to be associated with patient admission characteristics. HAC may an indicator of hospital admission complexity rather than hospital-acquired complications.

Modelling hospital outcome: problems with endogeneity

Background

Mortality modelling in the critical care paradigm traditionally uses logistic regression, despite the availability of estimators commonly used in alternate disciplines. Little attention has been paid to covariate endogeneity and the status of non-randomized treatment assignment. Using a large registry database, various binary outcome modelling strategies and methods to account for covariate endogeneity were explored.

Methods

Patient mortality data was sourced from the Australian & New Zealand Intensive Society Adult Patient Database for 2016. Hospital mortality was modelled using logistic, probit and linear probability (LPM) models with intensive care (ICU) providers as fixed (FE) and random (RE) effects. Model comparison entailed indices of discrimination and calibration, information criteria (AIC and BIC) and binned residual analysis. Suspect covariate and ventilation treatment assignment endogeneity was identified by correlation between predictor variable and hospital mortality error terms, using the Stata™ “eprobit” estimator. Marginal effects were used to demonstrate effect estimate differences between probit and “eprobit” models.

Results

The cohort comprised 92,693 patients from 124 intensive care units (ICU) in calendar year 2016. Patients mean age was 61.8 (SD 17.5) years, 41.6% were female and APACHE III severity of illness score 54.5(25.6); 43.7% were ventilated. Of the models considered in predicting hospital mortality, logistic regression (with or without ICU FE) and RE logistic regression dominated, more so the latter using information criteria indices. The LPM suffered from many predictions outside the unit [0,1] interval and both poor discrimination and calibration. Error terms of hospital length of stay, an independent risk of death score and ventilation status were correlated with the mortality error term. Marked differences in the ventilation mortality marginal effect was demonstrated between the probit and the "eprobit" models which were scenario dependent. Endogeneity was not demonstrated for the APACHE III score.

Conclusions

Logistic regression accounting for provider effects was the preferred estimator for hospital mortality modelling. Endogeneity of covariates and treatment variables may be identified using appropriate modelling, but failure to do so yields problematic effect estimates.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01251-8.

Incidence and management of metabolic acidosis with sodium bicarbonate in the ICU: An international observational study

BACKGROUND

Metabolic acidosis is a major complication of critical illness. However, its current epidemiology and its treatment with sodium bicarbonate given to correct metabolic acidosis in the ICU are poorly understood.

METHOD

This was an international retrospective observational study in 18 ICUs in Australia, Japan, and Taiwan. Adult patients were consecutively screened, and those with early metabolic acidosis (pH < 7.3 and a Base Excess < -4 mEq/L, within 24-h of ICU admission) were included. Screening continued until 10 patients who received and 10 patients who did not receive sodium bicarbonate in the first 24 h (early bicarbonate therapy) were included at each site. The primary outcome was ICU mortality, and the association between sodium bicarbonate and the clinical outcomes were assessed using regression analysis with generalized linear mixed model.

RESULTS

We screened 9437 patients. Of these, 1292 had early metabolic acidosis (14.0%). Early sodium bicarbonate was given to 18.0% (233/1292) of these patients. Dosing, physiological, and clinical outcome data were assessed in 360 patients. The median dose of sodium bicarbonate in the first 24 h was 110 mmol, which was not correlated with bodyweight or the severity of metabolic acidosis. Patients who received early sodium bicarbonate had higher APACHE III scores, lower pH, lower base excess, lower PaCO₂, and a higher lactate and received higher doses of vasopressors. After adjusting for confounders, the early administration of sodium bicarbonate was associated with an adjusted odds ratio (aOR) of 0.85 (95% CI, 0.44 to 1.62) for ICU mortality. In patients with vasopressor dependency, early sodium bicarbonate was associated with higher mean arterial pressure at 6 h and an aOR of 0.52 (95% CI, 0.22 to 1.19) for ICU mortality.

CONCLUSIONS

Early metabolic acidosis is common in critically ill patients. Early sodium bicarbonate is administered by clinicians to more severely ill patients but without correction for weight or acidosis severity. Bicarbonate therapy in acidotic vasopressor-dependent patients may be beneficial and warrants further investigation.

Safety of the endotracheal tube for prolonged mechanical ventilation

RATIONALE

The endotracheal tube (ETT) is the most common route for invasive mechanical ventilation (MV) yet controversy attends its long-term safety.

OBJECTIVE

Assess the safety of ETT compared with tracheostomy tube (TT) for MV support in the intensive care unit (ICU).

METHODS

Retrospective analysis of five year national dataset of 128,977 adults (age > 15-years) admitted for MV therapy with tracheostomy tube (TT; n = 4772) or without (ETT; n = 124,204), excluding those with neurological diagnoses or likely to require a surgical airway (n = 27,466), in 93 public health service ICUs across Australia, between July 2013-June 2018.

MEASUREMENTS

Hospital survival (including liberation from MV) for ETT Group compared with TT Group using a probit regression model adjusted for confounding using fixed, endogenous and non-random treatment assignment covariates, and their interactions; analysed and plotted as marginal effects by duration of MV.

RESULTS

Median duration of MV was 2 (IQR =1-4) days, predominantly via ETT (124,205; 96.3%), and 21,620 (16.7%) died. Temporal trend for ETT increased (OR = 1.06 per year, 95%CI =1.03-1.10) compared to TT, even for prolonged (>3 weeks) MV (38.1%). Higher risk-adjusted mortality was associated with longer duration of MV and after 9 days of MV with retention of ETT compared with TT - average (mortality) treatment effect 12.6% (95%CI =10.7-14.5). The latter was not significant after 30 days of MV.

CONCLUSIONS

The safety of ETT compared with TT beyond short-term MV (≤9-days) is uncertain and requires prospective evaluation with additional data.

Diabetic ketoacidosis in adult patients: an audit of factors influencing time to normalisation of metabolic parameters

BACKGROUND

Diabetic ketoacidosis (DKA) is an acute life-threatening metabolic complication of diabetes that imposes substantial burden on our healthcare system. There is a paucity of published data in Australia assessing factors influencing time to resolution of DKA and length of stay (LOS).

AIMS

To identify factors that predict a slower time to resolution of DKA in adults with diabetes.

METHODS

Retrospective audit of patients admitted to St Vincent's Hospital Melbourne between 2010 to 2014 coded with a diagnosis of 'Diabetic Ketoacidosis'. The primary outcome was time to resolution of DKA based on normalisation of biochemical markers. Episodes of DKA within the wider Victorian hospital network were also explored.

RESULTS

Seventy-one patients met biochemical criteria for DKA; median age 31 years (26-45 years), 59% were male and 23% had newly diagnosed diabetes. Insulin omission was the most common precipitant (42%). Median time to resolution of DKA was 11 h (6.5-16.5 h). Individual factors associated with slower resolution of DKA were lower admission pH (P < 0.001) and higher admission serum potassium level (P = 0.03). Median LOS was 3 days (2-5 days), compared to a Victorian state-wide LOS of 2 days. Higher comorbidity scores were associated with longer LOS (P < 0.001).

CONCLUSIONS

Lower admission pH levels and higher admission serum potassium levels are independent predictors of slower time to resolution of DKA. This may assist to stratify patients with DKA using markers of severity to determine who may benefit from closer monitoring and to predict LOS.

Use of resuscitation plans at a tertiary Australian hospital: room for improvement

BACKGROUND

The 'Acute Resuscitation Plan' (ARP) is a document for recording the resuscitation plans of patients at a tertiary hospital for adult patients. The ARP was introduced at the hospital in September 2014, superseding the 'Not for Cardiopulmonary Resuscitation (CPR)' form. Unlike the Not for CPR form, the ARP was relevant to patients with and without resuscitation limits.

AIM

To evaluate the introduction of the ARP.

METHODS

This study is a retrospective audit of the records of all admissions to the hospital from January to June 2014 (Not for CPR period) and January to June 2015 (ARP period). The main outcomes are the incidence of resuscitation plans, the proportion of ARP specifying consultation with the patient (or representative) and with senior medical staff, and the proportion of ARP among older patients and those with significant comorbidity.

RESULTS

Resuscitation plans were present for 453 of 23 325 (1.9%) admissions in the Not for CPR period versus 1801 of 24 037 (7.5%) in the ARP period (odds ratio (OR) 4.1, 95% confidence interval (CI) 3.7-4.5, P < 0.001). A total of 42% of ARP specified 'care of the dying' in the event of arrest. Acknowledgement of the views of the patient (or representative) was indicated on 37% of ARP and of a senior physician on 28%. An ARP was not present for 67% of patients aged ≥90 years, 59% from aged care, 90% with metastatic cancer and 64% aged ≥80 years and with a Charlson comorbidity index ≥3.

CONCLUSIONS

More patients had resuscitation plans after introducing the ARP. However, patients and senior physicians were often remote from the consultation process, and an ARP was not present for many patients likely to have a poor outcome from cardiopulmonary arrest.

Rapid response team diagnoses: frequencies and related hospital mortality

OBJECTIVES

To describe the frequency and hospital mortality of problems (diagnoses) encountered by a rapid response team (RRT), and to identify the most common diagnoses for RRT triggers and for treating units.

DESIGN

For each RRT event in 2015 at a tertiary hospital for adults, we chose the diagnosis that best explained the RRT event from a pre-defined list after reviewing relevant test results and clinical notes.

RESULTS

There were 937 RRT events during 700 admissions and there were 58 different RRT diagnoses in 11 diagnosis groups. The largest groups were neurological and consciousness problems (22.9%), circulatory problems (19.0%) and breathing problems (16.0%). The most common diagnoses were rapid atrial fibrillation (7.6%) and oversedation or narcosis (4.8%). When SpO₂ < 90% triggered RRT review, the leading diagnoses were complex respiratory failure (25.9%) and pneumonia (11.4%). When decreased conscious state triggered review, the main problems were neurological, but there were 39 different diagnoses among these cases. The main problems among orthopaedic cases were post-operative hypovolaemia (19.0%) and spinal anaesthetic-related or epidural analgesicrelated hypotension (15.2%). Hospital mortality was 101/700 (14.4%). Diagnoses with high mortality included gastrointestinal bleeding (4/17, 23.5%), complex respiratory failure (8/33, 24.2%), intracranial event (8/28, 28.6%), cardiogenic shock or acute heart failure (5/17, 29.4%), pneumonia (7/21, 33.3%), chest sepsis (5/11, 45.5%) and cardiac arrest (18/26, 69.2%).

CONCLUSIONS

The RRT activation trigger provides only a general indication of the diagnosis. Some problems appear preventable and could provide a focus for unit-based quality initiatives. The mortality of some diagnoses is substantial, and this may help in setting treatment goals, but more work is needed to understand the association of RRT diagnosis and outcome.

The impact of an education program and written guideline on adherence to low tidal volume ventilation

BACKGROUND

Low tidal volume ventilation reduces mortality in patients with acute lung injury (ALI) and may reduce the risk of ALI in ventilated patients. A previous audit of our ventilation practices showed poor adherence to low tidal volume ventilation, and we subsequently introduced written ventilation guidelines and an education program to change practice.

OBJECTIVES

To determine if adherence to low tidal volume ventilation (defined as mandatory tidal volumes of =?6.5 mL/ kg predicted body weight [PBW]) in ventilated patients was improved with a written guideline and staff education.

DESIGN AND SETTING

Retrospective analysis of recorded mandatory ventilator settings from the clinical information system of a tertiary referral intensive care unit from 1 January 2012 to 31 December 2015, involving analysis of mandatory ventilator settings in relation to PBW to determine adherence to guidelines, and interrupted time-series analysis to assess the impact of education.

MAIN OUTCOME MEASURE

Adherence to low tidal volume ventilation.

RESULTS

The mean tidal volume for the cohort was 7.4 mL/ kg (SD, 1.3 mL/kg) PBW, and 760 patients (26.9%) received an average tidal volume during mandatory ventilation of ≤6.5 mL/kg PBW. Interrupted time-series analysis showed improved adherence after education, with an increase in adherence of 29.4% (95% CI, 19.3%-39.5%) from baseline. Multivariate logistic analysis found height, weight and staff education, but not sex, were associated with adherence to low tidal volume ventilation.

CONCLUSION

Written protocols and education can influence clinician behaviour, with substantial improvements in adherence to low tidal volume ventilation. Efforts to improve adherence through ward-based education appear warranted and necessary. Adherence was strongly associated with patient height, which suggested that adherence was partly the result of chance rather than design.

A trial of nebulised heparin to limit lung injury following cardiac surgery

Cardiac surgery with cardiopulmonary bypass triggers an acute inflammatory response in the lungs. This response gives rise to fibrin deposition in the microvasculature and alveoli of the lungs. Fibrin deposition in the microvasculature increases alveolar dead space, while fibrin deposition in alveoli causes shunting. We investigated whether prophylactic nebulised heparin could limit this form of lung injury. We undertook a single-centre double-blind randomised trial. Forty patients undergoing elective cardiac surgery with cardiopulmonary bypass were randomised to prophylactic nebulised heparin (50,000 U) or placebo. The primary endpoint was the change in arterial oxygen levels over the operative period. Secondary endpoints included end-tidal CO₂, the alveolar dead space fraction and bleeding complications. We found nebulised heparin did not improve arterial oxygen levels. Nebulised heparin was, however, associated with a lower alveolar dead space fraction (P <0.05) and lower tidal volumes at the end of surgery (P <0.01). Nebulised heparin was not associated with bleeding complications. In conclusion, prophylactic nebulised heparin did not improve oxygenation, but was associated with evidence of better alveolar perfusion and CO₂elimination at the end of surgery.

Towards defining persistent critical illness and other varieties of chronic critical illness

We hypothesise that there exists a substantial and growing group of "persistently critically ill" patients who appear to be intensive care unit-dependent because of a cascade of critical illnesses rather than their original ICU admitting diagnosis. These persistently critically ill patients are those who remain in the ICU because of ongoing complications of care that continue after their reason for admission has been treated and is no longer active. We believe such patients can be distinguished from patients currently labelled as "chronic critical illness" or "prolonged mechanical ventilation". We further believe that their primary problem is not simply failure to wean from mechanical ventilation due to muscle weakness and impaired gas exchange. We outline a program of clinician consultation, epidemiological research, consensus conference and validation to develop a useful definition of persistent critical illness, with the aim of supporting investigations in preventing persistence, and improving the care of patients so affected.

The timing of discharge from the intensive care unit and subsequent mortality. A prospective, multicenter study

RATIONALE

Previous studies suggested an association between after-hours intensive care unit (ICU) discharge and increased hospital mortality. Their retrospective design and lack of correction for patient factors present at the time of discharge make this association problematic.

OBJECTIVES

To determine factors independently associated with mortality after ICU discharge.

METHODS

This was a prospective, multicenter, binational observational study involving 40 ICUs in Australia and New Zealand. Participants were consecutive adult patients discharged alive from the ICU between September 2009 and February 2010.

MEASUREMENTS AND MAIN RESULTS

We studied 10,211 patients discharged alive from the ICU. Median age was 63 years (interquartile range, 49-74), 6,224 (61%) were male, 5,707 (56%) required mechanical ventilation, and their median Acute Physiology and Chronic Health Evaluation III risk of death was 9% (interquartile range, 3-25%). A total of 8,539 (83.6%) patients were discharged in-hours (06:00-18:00) and 1,672 (16.4%) after-hours (18:00-06:00). Of these, 408 (4.8%) and 124 (7.4%), respectively, subsequently died in hospital (P < 0.001). After risk adjustment for markers of illness severity at time of ICU discharge including limitations of medical therapy (LOMT) orders, the time of discharge was no longer a significant predictor of mortality. The presence of a LOMT order was the strongest predictor of death (odds ratio, 35.4; 95% confidence interval, 27.5-45.6).

CONCLUSIONS

In this large, prospective, multicenter, binational observational study, we found that patient status at ICU discharge, particularly the presence of LOMT orders, was the chief predictor of hospital survival. In contrast to previous studies, the timing of discharge did not have an independent association with mortality.

Do we practise low tidal-volume ventilation in the intensive care unit? a 14-year audit

BACKGROUND

Low tidal volume ventilation (LTVV) has been shown to reduce mortality of patients with acute lung injury (ALI) but uptake by clinicians has been low. Recent studies have shown that LTVV results in survival benefit at 24 months after discharge and, importantly, benefits patients without ALI.

OBJECTIVE

To determine adherence to LTVV in patients on mechanical ventilation (MV).

DESIGN, SETTING AND PARTICIPANTS

Retrospective analysis of ventilator settings recorded within the clinical information system of a 15-bed general ICU in a tertiary referral hospital, between 1 January 2000 and 31 May 2013.

METHODS

Analysis of mandatory MV with volume or pressure control.

MAIN OUTCOME MEASURES

Adherence to LTVV (_6.5 mL/ kg predicted body weight [PBW]).

RESULTS

We studied 4923 patients with a median age of 66 years (interquartile range [IQR], 57-74 years), and a median Acute Physiology and Chronic Health Evaluation II score of 16 (IQR, 13-19). Included were 3486 men (70.8%), and 3386 (66.8%) had undergone cardiac surgery. There were 249 450 ventilator measurements, with a median per patient of 75 measurements (IQR, 17-255 measurements). The median tidal volume was 8.15 mL/kg PBW (IQR, 7.15- 9.34 mL/kg PBW) for an adherence of 13.4%. Independent factors associated with adherence were sex, high inspiratory pressures, high positive end expiratory pressure and low PaO2/FiO2 ratio.

CONCLUSION

Adherence to LTVV in a general cohort of ICU patients was low, but it was better in patients with more severe lung disease. Overestimation of PBW may have contributed to our findings. Regular auditing of LTVV adherence might be considered a clinical indicator of good MV practice.

The duration of hospitalization before review by the rapid response team: A retrospective cohort study

PURPOSE

The purpose of this study is to compare cases of rapid response team (RRT) review for early deterioration (<48 hours after admission), intermediate deterioration (48 to <168 hours after admission), late deterioration (≥168 hours after admission), and cardiac arrest and to determine the association between duration of hospitalization before RRT review and mortality.

METHODS

This is a retrospective cohort study of RRT cases from a single hospital over 5 years (2009-2013) using administrative data and data for the first RRT attendance of each hospital episode.

RESULTS

Of 2843 RRT cases, 971 (34.2%) were early deterioration, 917 (32.3%) intermediate, 775 (27.3%) late, and 180 (6.3%) cardiac arrest. Compared with early deterioration patients, late deterioration patients were older (median, 71 vs 69 years; P = .005), had a higher Charlson comorbidity index (median, 2 vs 1; P < .001), more often had RRT review for respiratory distress (32.5% vs 23.5%; P < .001), more often received RRT-initiated not for resuscitation orders (8.4% vs 3.9%; P < .001), less often were discharged directly home (27.9% vs 58.4%; P < .001), and more often died in hospital (30.6% vs 12.8%; P < .001). Compared with early deterioration and adjusted for confounders, the odds ratio of death in hospital for late deterioration was 2.36 (1.81-3.08; P < .001).

CONCLUSIONS

Late deterioration is frequently encountered by the RRT and, compared with early deterioration, is associated with greater clinical complexity and a worse hospital outcome.

Paracetamol therapy and outcome of critically ill patients: a multicenter retrospective observational study

Introduction

In this study, we aimed to examine the association between paracetamol administration in the intensive care unit (ICU) and mortality in critically ill patients.

Methods

We conducted a multicenter retrospective observational study in four ICUs. We obtained information on paracetamol use, body temperature, demographic, clinical and outcome data from each hospital’s clinical information system and admissions and discharges database. We performed statistical analysis to assess the association between paracetamol administration and hospital mortality.

Results

We studied 15,818 patients with 691,348 temperature measurements at 4 ICUs. Of these patients, 10,046 (64%) received at least 1 g of paracetamol. Patients who received paracetamol had lower in-hospital mortality (10% vs. 20%, P <0.001), and survivors were more likely to have received paracetamol (66% vs. 46%; P <0.001). However, patients treated with paracetamol were also more likely to be admitted to the ICU after surgery (70% vs. 51%; P <0.001) and/or after elective surgery (55% vs. 37%; P <0.001). In multivariate logistic regression analysis including a propensity score for paracetamol treatment, we found a significant and independent association between the use of paracetamol and reduced in-hospital mortality (adjusted odds ratio =0.60 (95% confidence interval (CI), 0.53 to 0.68), P <0.001). Cox proportional hazards analysis showed that patients who received paracetamol also had a significantly longer time to death (adjusted hazard ratio =0.51 (95% CI, 0.46 to 0.56), P <0.001). The association between paracetamol and decreased mortality and/or time to death was broadly consistent across surgical and medical patients. It remained present after adjusting for paracetamol administration as a time-dependent variable. However, when such time-dependent analysis was performed, the association of paracetamol with outcome lost statistical significance in the presence of fever and suspected infection and in patients in the lower tertiles of Acute Physiology and Chronic Health Evaluation II scores.

Conclusions

Paracetamol administration is common in the ICU and appears to be independently associated with reduced in-hospital mortality and time to death after adjustment for multiple potential confounders and propensity score. This association, however, was modified by the presence of fever, suspected infection and lesser illness severity and may represent the effect of indication bias.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0865-1) contains supplementary material, which is available to authorized users.

Changing clinical guidelines from delayed to early aperient administration for enterally fed intensive care patients was associated with increased diarrhoea: a before-and-after, intention-to-treat evaluation

BACKGROUND

The 14-bed intensive care unit of a tertiary referral hospital adopted a guideline to start docusate sodium with sennosides when enteral nutrition was started. This replaced a guideline to start aperients after 24h of enteral nutrition if no bowel action had occurred. We sought to determine the effect of this change on the incidence of diarrhoea and constipation in intensive care.

METHODS

Retrospective audit of the medical records of consecutive adult patients admitted to intensive care and given enteral nutrition, excluding those with a primary gastrointestinal system diagnosis, between Jan-Aug 2011 (the delayed group, n=175) and Jan-Aug 2012 (the early group, n=175). The early aperient guideline was implemented during Sep-Dec 2011.

RESULTS

The early and delayed groups were similar in age (median 62 years vs. 64 years; P=0.17), sex (males 65% vs. 63%; P=0.91), and postoperative cases (31% vs. 33%; P=0.82) and had similar proportions who received mechanical ventilation (95% vs. 95%; P=1.00), an inotrope or vasopressor (63% vs. 70%; P=0.17), renal replacement therapy (8% vs. 10%; P=0.71), opiates (77% vs. 80%; P=0.60), antibiotics (89% vs. 91%; P=0.72) and metoclopramide (46% vs. 55%; P=0.11). A significantly larger proportion of the early group received an aperient (54% vs. 29%, P<0.001) and experienced diarrhoea (38% vs. 27%, P=0.04), but the groups had similar proportions affected by constipation (42% vs. 43%, P=0.91).

CONCLUSIONS

Changing guidelines from delayed to early aperient administration was associated with an increase in the incidence of diarrhoea but was not associated with the incidence of constipation. These findings do not support changing guidelines from delayed to early aperient administration.