The mortality associated with review by the rapid response team for non-arrest deterioration: a cohort study of acute hospital adult patients

OBJECTIVES

To compare the admission characteristics, discharge destination and mortality of patients reviewed by the rapid response team (RRT) for deterioration with those of other hospital patients; and to determine the association between RRT review for deterioration and mortality.

DESIGN, SETTING AND PATIENTS

Acute admissions of adult patients to a tertiary hospital between 1 January 2008 and 31 December 2011 were identified from administrative data. Data for each patient's first admission were merged with RRT data on the first RRT event of each admission, if any. RRT events involving cardiac arrest were classified as arrest events and all others as deterioration events.

RESULTS

Of 43 385 patients in the cohort, 1117 (2.57%) had RRT review for deterioration and 91 (0.21%) for cardiac arrest. Deterioration events occurred a median of 3.23 days after admission. Advanced treatments were instituted in 38.59% of deterioration events, and a new not-for resuscitation order for 5.55%. Compared with those not reviewed by the RRT, patients in the deterioration group were older (median, 70 v 60 years, P < 0.001) and had a higher Charlson comorbidity index (median, 1 v 0, P < 0.001). They also more often died in hospital (18.80% v 1.42%, P < 0.001) or were discharged to another hospital (37.51% v 13.39%, P < 0.001) and more often died in the 90 days after admission (24.44% v 3.48%, P < 0.001). Their adjusted odds ratio of death in the 90 days after admission was 5.85 (95% CI, 4.97-6.89, P < 0.001).

CONCLUSION

Patients reviewed for deterioration were older and had greater comorbidity than patients the RRT was not called to review. RRT review for deterioration was an independent risk factor for mortality.

Outcomes of older people receiving intensive care in Victoria

OBJECTIVE To assess trends in service use and outcome of critically ill older people (aged ≥ 65 years) admitted to an intensive care unit (ICU).

DESIGN, PATIENTS AND SETTING

Retrospective cohort analysis of administrative data on older patients discharged from ICUs at all 23 adult public hospitals with onsite ICUs in Victoria between 1 July 1999 and 30 June 2011. Subgroups examined included those aged ≥ 80 years, major diagnosis categories, and those receiving mechanical ventilation.

MAIN OUTCOME MEASURES

Resource use and hospital survival; also length of stay (LOS) and discharge destination trends.

RESULTS

Over 12 years, 108,171 people aged ≥ 65 years were admitted to ICUs; of these, 49,912 (46.1%) received mechanical ventilation and 17,772 (16.4%) died. Despite an increase in the older age population (2.5% per annum) and acute care admissions (7.3% per annum) over the period studied, there was a net reversal in prevalence trends for ICU admissions (- 1.7% per annum; P = 0.04) and admissions of patients requiring mechanical ventilation (- 1.6% per annum) in the 8 years since 2004. Annual risk-adjusted mortality fell (odds ratio, 0.97 per year; 95% CI, 0.96-0.97 per year; P < 0.001) without prolongation of hospital or ICU LOS (P = 0.49) or discharge to residential aged care (RAC). Similar trends were noted in all a priori subgroups.

CONCLUSIONS

Improved hospital survival without an increase in demand for ICU admission or RAC or an increase in LOS suggests there has been improvement in the care of the older age population.

A brief review of recent trends in Victorian intensive care, 2000-2011

BACKGROUND

Review of resource use and patient outcomes of intensive care unit services over time provides insights into service delivery and safety.

OBJECTIVE

To examine temporal trends in resource consumption and risk-adjusted mortality of adult ICU patients in Victoria.

DESIGN, PARTICIPANTS AND SETTING

Retrospective cohort study of 214 619 adult ICU admissions recorded from 23 major hospitals over 12 years from 1 July 1999 to 30 June 2011.

OUTCOMES

Primary outcomes were population rates of ICU admission and mechanical ventilation (MV), ICU and hospital length of stay, and hospital survival. Secondary outcomes included average ICU and MV bed numbers. Administrative data were derived from the Victorian Admitted Episodes Dataset and the Australian Bureau of Statistics. The Critical Care Outcome Prediction Equation informed estimates for risk-adjusted mortality. Temporal mortality trends were evaluated for outcome estimates and hierarchical logisticregression trends were evaluated for risk-adjusted mortality.

RESULTS

Of ICU admissions, 104 103 (48.5%) were patients who received MV, and 87.6% ICU admissions were adults who survived to hospital discharge. There was a decline in the risk-adjusted mortality (odds ratio, 0.967 per year; 95% CI, 0.963-0.971; P<0.001). Similar results were found in 17 hospitals (74%) and in nine of 10 major diagnostic subgroups. There was an increase of 5.2 occupied ICU beds per year (range, ?4.2 ICU beds per year; P=0.002). Despite ICU admissions being a minority cohort (2.5% of public hospital admissions) this group used 8.6% of hospital bed-days and attracted 19.5% of funding.

CONCLUSIONS

There was an increase in ICU resource availability and evidence of improvement in hospital survival, suggesting improved quality of care. These evaluation methods may be useful in monitoring statewide capacity, service delivery and patient safety.

The operating surgeon is an independent predictor of chest tube drainage following cardiac surgery

OBJECTIVES

Bleeding into the chest is a major cause of blood transfusion and adverse outcomes following cardiac surgery. The authors investigated predictors of bleeding following cardiac surgery to identify potentially correctable factors.

DESIGN

Data were retrieved from the medical records of patients undergoing cardiac surgery over the period of 2002 to 2008. Multivariate analysis was used to identify the independent predictors of chest tube drainage.

SETTING

Tertiary hospital.

PARTICIPANTS

Two thousand five hundred seventy-five patients.

INTERVENTIONS

Cardiac surgery.

RESULTS

The individual operating surgeon was independently associated with the extent of chest tube drainage. Other independent factors included internal mammary artery grafting, cardiopulmonary bypass time, urgency of surgery, tricuspid valve surgery, redo surgery, left ventricular impairment, male gender, lower body mass index and higher preoperative hemoglobin levels. Both a history of diabetes and administration of aprotinin were associated with reduced levels of chest tube drainage.

CONCLUSIONS

The individual operating surgeon was an independent predictor of the extent of chest tube drainage. Attention to surgeon-specific factors offers the possibility of reduced bleeding, fewer transfusions, and improved patient outcomes.

Development and validation of the critical care outcome prediction equation, version 4

OBJECTIVE

To revise and validate the accuracy of the critical care outcome prediction equation (COPE) model, version 4.

DESIGN, PARTICIPANTS AND SETTING

Observational cohort analysis of 214 616 adult consecutive intensive care unit admissions recorded from 23 ICUs over 12 years. Data derived from the Victorian Admitted Episode Database (VAED) were used to identify treatment-independent risk factors consistently associated with hospital mortality. A revised version of the COPE-4 model using a random intercept hierarchical logistic regression model was developed in a sample of 35 878 (16.7%) consecutive ICU separations.

MAIN OUTCOME MEASURES

Accuracy was tested by comparing observed and predicted mortality in the remaining 178 741 (83.3%) records and in 23 institutional cohorts. Stability was assessed using the standardised mortality ratio, Hosmer-Lemeshow H10 statistic, calibration plot and Brier score.

RESULTS

The COPE-4 model had satisfactory overall discrimination with an area under receiver operating characteristic curve of 0.82 for both datasets. The development and validation datasets demonstrated good overall calibration with H10 statistics of 13.38 (P = 0.10) and 14.84 (P = 0.06) and calibration plot slopes of 0.99 and 1.034, respectively. Discrimination was satisfactory in all 23 hospitals and one or more calibration criteria were achieved in 19 hospitals (83%).

CONCLUSIONS

COPE-4 model prediction of hospital mortality for ICU admissions has satisfactory performance for use as a risk-adjustment tool in Victoria. Model refinement may further improve its performance.

Medical emergency teams are associated with reduced mortality across a major metropolitan health network after two years service: a retrospective study using government administrative data

Introduction

Medical emergency teams (MET) are implemented to ensure prompt clinical review of patients with deteriorating physiology with the intention of averting further deterioration, cardiac arrest and death. We sought to determine if MET implementation has led to reductions in hospital mortality across a large metropolitan health network utilising routine administrative data submitted by hospitals to the Department of Health Victoria.

Methods

The Victorian admissions episodes data set (VAED) contains data on all individual hospital separations in the State of Victoria, Australia. After gaining institutional ethics approval, we extracted data on all acute admissions to metropolitan hospitals for which we had information on the presence and timing of a MET system. Using logistic regression we determined whether there was an effect of MET implementation on mortality controlling for age, gender, Charlson comorbidity diagnostic groupings, emergency admission, same day admission, ICU admission, mechanical ventilation, year, indigenous ethnicity, liaison nurse service and hospital designation.

Results

5911533 individual admissions and 73,599 associated deaths from July 1999 to June 2010 were included in the analysis. 52.2% were male and median age was 57(42-72 IQR). Mortality rates for MET and non-MET periods were 3.92 (3.88-3.95 95%CI) and 4.56 (4.51-4.61 95%CI) deaths per 1000 patient days with a rate ratio after adjustment for year of 0.88 (0.86-0.89 95%CI) P < 0.001. In a multivariable logistic regression, mortality was associated with a MET team being active in the hospital for more than 2 years. The odds ratio for mortality in hospitals where a MET system had been in place for greater than 4 years duration was 0.90 (0.88-0.92). Mortality during the first 2 years of a MET system being in place was not statistically different from pre-MET periods.

Conclusions

Utilising routinely collected administrative data we demonstrated that the presence of a hospital MET system for greater than 2 years was associated with an independent reduction in hospital mortality across a major metropolitan health network. Mortality benefits after the introduction of a MET system take time to become apparent.

Medical emergencies in the imaging department of a university hospital: event and imaging characteristics

We aimed to describe the characteristics of medical emergencies that occurred in the medical imaging department (MID) of a university hospital in Melbourne, Australia. A database of 'Respond Medical Emergency Team (MET)' and 'Respond Blue' calls was retrospectively examined for the period June 2003 to November 2010 in relation to events that occurred in the MID. The hospital medical imaging database was also examined in relation to these events and, where necessary, patients' notes were reviewed. Ethics approval was granted by the hospital ethics review board. There were 124 medical emergency calls in the MID during the study period, 28% Respond Blue and 72% Respond MET. Of these 124 calls, 26% occurred outside of usual work hours and 12% involved cardiac arrest. The most common reasons for the emergency calls were seizures (14%) and altered conscious state (13%). Contrast anaphylaxis precipitated the emergency in 4% of cases. In 83% of cases the emergency calls were for patients attending the MID for diagnostic imaging, the remainder being for a procedure. Of the scheduled imaging techniques, 45% were for computed tomography. The scheduled imaging was abandoned due to the emergency in 12% of cases. When performed, imaging informed patient management in 34% of cases in diagnostic imaging and in all cases in the context of image-guided procedures. Medical emergency calls in the MID often occurred outside usual work hours and were attributed to a range of medical problems. The emergencies occurred in relation to all imaging techniques and imaging informed patient management in many cases.

Age of red blood cells and mortality in the critically ill

Introduction

In critically ill patients, it is uncertain whether exposure to older red blood cells (RBCs) may contribute to mortality. We therefore aimed to evaluate the association between the age of RBCs and outcome in a large unselected cohort of critically ill patients in Australia and New Zealand. We hypothesized that exposure to even a single unit of older RBCs may be associated with an increased risk of death.

Methods

We conducted a prospective, multicenter observational study in 47 ICUs during a 5-week period between August 2008 and September 2008. We included 757 critically ill adult patients receiving at least one unit of RBCs. To test our hypothesis we compared hospital mortality according to quartiles of exposure to maximum age of RBCs without and with adjustment for possible confounding factors.

Results

Compared with other quartiles (mean maximum red cell age 22.7 days; mortality 121/568 (21.3%)), patients treated with exposure to the lowest quartile of oldest RBCs (mean maximum red cell age 7.7 days; hospital mortality 25/189 (13.2%)) had an unadjusted absolute risk reduction in hospital mortality of 8.1% (95% confidence interval = 2.2 to 14.0%). After adjustment for Acute Physiology and Chronic Health Evaluation III score, other blood component transfusions, number of RBC transfusions, pretransfusion hemoglobin concentration, and cardiac surgery, the odds ratio for hospital mortality for patients exposed to the older three quartiles compared with the lowest quartile was 2.01 (95% confidence interval = 1.07 to 3.77).

Conclusions

In critically ill patients, in Australia and New Zealand, exposure to older RBCs is independently associated with an increased risk of death.

Fluid therapy using a balanced crystalloid solution and acid-base stability after cardiac surgery

OBJECTIVE

To evaluate the effect of fluid therapy using Accusol (Baxter Healthcare, McGaw Park, Ill, USA), a crystalloid solution containing sodium bicarbonate and other electrolytes and having a strong ion difference of 35 mEq/L, on acid-base stability after cardiac surgery.

DESIGN

Retrospective per-protocol comparison.

SETTING

Intensive care unit of St Vincent's Hospital, a teaching hospital in Melbourne, Australia.

PARTICIPANTS

Consecutive adult patients admitted in daytime hours after elective on-pump coronary artery bypass graft surgery between May and October 2008 constituted the "pre-Accusol group" (n=40), and those admitted between May and October 2009 and who were treated with Accusol constituted the "Accusol group" (n=51).

MAIN OUTCOME MEASURES

The fluids and their component electrolytes administered; change in standard base excess (SBE) between the time of intensive care admission and 04:00 h the next day.

RESULTS

The Accusol group received a median Accusol dose of 1.86 mL/kg/h (interquartile range, 1.51-2.20 mL/ kg/h), which accounted for 38% (SD, 10%) of the total volume of fluid administered. The change in SBE was +0.03mmol/L (95% CI, -0.57 to 0.64 mmol/L; P = 0.91) in the Accusol group compared with -2.05mmol/L (95% CI, -2.64 to -1.45; P < 0.01) in the pre-Accusol group. The strong ion difference of the electrolytes administered as components of fluid therapies was higher in the Accusol group by 55.5mEq (95% CI, 40.0 to 71.0mEq; P < 0.01). Only 8% of the Accusol group received albumin compared with 48% of the pre-Accusol group (P < 0.01).

CONCLUSIONS

SBE was more stable in patients treated with Accusol. Further studies are needed to determine whether use of solutions such as Accusol influences important patient outcomes.

Nebulized heparin is associated with fewer days of mechanical ventilation in critically ill patients: a randomized controlled trial

Introduction

Prolonged mechanical ventilation has the potential to aggravate or initiate pulmonary inflammation and cause lung damage through fibrin deposition. Heparin may reduce pulmonary inflammation and fibrin deposition. We therefore assessed whether nebulized heparin improved lung function in patients expected to require prolonged mechanical ventilation.

Methods

Fifty patients expected to require mechanical ventilation for more than 48 hours were enrolled in a double-blind randomized placebo-controlled trial of nebulized heparin (25,000 U) or placebo (normal saline) 4 or 6 hourly, depending on patient height. The study drug was continued while the patient remained ventilated to a maximum of 14 days from randomization.

Results

Nebulized heparin was not associated with a significant improvement in the primary end-point, the average daily partial pressure of oxygen to inspired fraction of oxygen ratio while mechanically ventilated, but was associated with improvement in the secondary end-point, ventilator-free days amongst survivors at day 28 (22.6 ± 4.0 versus 18.0 ± 7.1, treatment difference 4.6 days, 95% CI 0.9 to 8.3, P = 0.02). Heparin administration was not associated with any increase in adverse events.

Conclusions

Nebulized heparin was associated with fewer days of mechanical ventilation in critically ill patients expected to require prolonged mechanical ventilation. Further trials are required to confirm these findings.

Trial registration

The Australian Clinical Trials Registry (ACTR-12608000121369).

Automated external defibrillators and survival after in-hospital cardiac arrest: early experience at an Australian teaching hospital

OBJECTIVE

To evaluate the effect of the introduction of automated external defibrillators (AEDs) on survival after inhospital cardiac arrest.

DESIGN, SETTING AND PARTICIPANTS

Before-and-after study that compared patients during the 2 years before (8 November 2005 to 7 November 2007) and the year after (8 November 2007 to 7 November 2008) the deployment of AEDs to the non-critical care areas of a university teaching hospital.

MAIN OUTCOME MEASURES

Return of spontaneous circulation (ROSC) and survival to hospital discharge.

RESULTS

55 in-hospital cardiac arrests occurred in the 2-year pre-AED period and 31 in the 1-year AED period. Patients had similar baseline characteristics in the pre-AED and AED periods including witnessed arrest (53% v 48%), arrest in an acute inpatient ward (78% v 90%), and initial arrest rhythm of pulseless ventricular tachycardia or ventricular fibrillation (18% v 16%). The proportions of patients with ROSC were similar in the pre-AED and AED periods (42% v 55%), as were the proportions who survived to hospital discharge (22% v 29%). In the AED period, the relative risk of ROSC was 1.31 (95% CI, 0.84- 2.04) and the relative risk of survival to hospital discharge was 1.33 (95% CI, 0.63-2.80).

CONCLUSIONS

ROSC and survival to hospital discharge did not change significantly after deployment of AEDs. The existence of a timely and robust resuscitation response with relatively good baseline outcomes, and the low proportion of initial shockable arrest rhythms may have limited the capacity of AEDs to improve survival.

Interventions to circumvent intensive care access block: a retrospective 2-year study across metropolitan Melbourne

OBJECTIVES

To measure the prevalence of interventions used to circumvent intensive care access block and to estimate the attributable mortality and additional hospital bed-days associated with them.

DESIGN AND SETTING

Retrospective observational study of 11 adult public hospital intensive care units (ICUs) in Melbourne, Victoria, July 2004 - June 2006.

MAIN OUTCOME MEASURES

Prevalence of five interventions in response to access block; attributable fatalities and/or increased length of stay associated with each.

RESULTS

21 896 ICU admissions and 3039 inhospital deaths (13.9%) were screened. All hospitals reported ICU access block. There were 6787 interventions for access block (mean, 9.3/day) -- 4070 (18.6% of admissions) instances of after-hours step-down from an ICU to a low-acuity ward; 1115 (5.1%) delays in an emergency department > 8 hours; 895 (4.1%) postponed major surgeries; 487 (2.2%) interhospital transfers; and 220 (1.0%) instances of premature cessation of intensive care. Based on published risk estimates, these interventions may have resulted in 91.1 (95% CI, 34.7-147.2) attributable deaths and 4368 (95% CI, 333-10 050) additional hospital bed-days each year.

CONCLUSIONS

Intensive care access block is frequent, and measures to circumvent it increase mortality and length of stay. Further study of the health and financial implications of access block are warranted.

A phase 1 trial of nebulised heparin in acute lung injury

Introduction

Animal studies of acute lung injury (ALI) suggest nebulised heparin may limit damage from fibrin deposition in the alveolar space and microcirculation. No human studies have been undertaken to date. We assessed the feasibility, safety and potential anticoagulant effects of administration of nebulised heparin to patients with ALI.

Methods

An open label phase 1 trial of four escalating doses of nebulised heparin was performed. A total of 16 ventilated patients with ALI were studied. The first group was administered a total of 50,000 U/day, the second group 100,000 U/day, the third group 200,000 U/day and the fourth group 400,000 U/day. Assessments of lung function included the PaO₂/FiO₂ ratio, lung compliance and the alveolar dead space fraction. Monitoring of anticoagulation included the activated partial thromboplastin time (APTT) and the thrombin clotting time. Bronchoalveolar lavage fluid was collected and the prothrombin fragment and tissue plasminogen activator levels were assessed. Analysis of variance was used to compare the effects of dose.

Results

No serious adverse events occurred for any dose. The changes over time for the PaO₂/FiO₂ ratio, lung compliance and the alveolar dead space fraction levels were similar for all doses. A trend to increased APTT and thrombin clotting time levels was present with higher doses (P = 0.09 and P = 0.1, respectively). For the highest dose, the APTT reached 64 seconds; following cessation of nebulised heparin, the APTT fell to 39 seconds (P = 0.06). In bronchoalveolar lavage samples a trend to reduced prothrombin fragment levels was present with higher doses (P = 0.1), while tissue plasminogen activator levels were similar for all doses.

Conclusion

Administration of nebulised heparin to mechanically ventilated patients with ALI is feasible. Nebulised heparin was not associated with any serious adverse events, and at higher doses it increased APTT levels. Larger trials are required to further investigate the safety and efficacy of nebulised heparin. In these trials due consideration must be given to systemic anticoagulant effects.

Trial registration

Australian Clinical trials registry ACTRN12606000388516.

An intensivist-led tracheostomy review team is associated with shorter decannulation time and length of stay: a prospective cohort study

INTRODUCTION

Without specific strategies to address tracheostomy care on the wards, patients discharged from the intensive care unit (ICU) with a tracheostomy may receive suboptimal care. We formed an intensivist-led multidisciplinary team to oversee ward management of such patients. To evaluate the service, we compared outcomes for the first 3 years of the service with those in the year preceding the service.

METHODS

Data were prospectively collected over the course of 3 years on ICU patients not under the care of the ear, nose, and throat unit who were discharged to the ward with a tracheostomy and compared with outcomes in the year preceding the introduction of the service. Principal outcomes were decannulation time, length of stay after ICU discharge, and stay of less than 43 days (upper trim point for the disease-related group [DRG] for tracheostomy). Analysis included trend by year and multivariable analysis using a Cox proportional hazards model. P values of less than 0.05 were assumed to indicate statistical significance. As this was a quality assurance project, ethics approval was not required.

RESULTS

Two hundred eighty patients were discharged with a tracheostomy over the course of a 4-year period: 41 in 2003, 60 in 2004, 95 in 2005, and 84 in 2006. Mean age was 61.8 (13.1) years, 176 (62.9%) were male, and mean APACHE (Acute Physiology and Chronic Health Evaluation) II score was 20.4 (6.4). Length of stay after ICU decreased over time (30 [13 to 52] versus 19 [10 to 34] days; P < 0.05 for trend), and a higher proportion of decannulated patients were discharged under the upper DRG trim point of 43 days (48% versus 66%; P < 0.05). Time to decannulation after ICU discharge decreased (14 [7 to 31] versus 7 [3 to 17] days; P < 0.01 for trend). Multivariate analysis showed that the hazard for decannulation increased by 24% (3% to 49%) per year.

CONCLUSION

An intensivist-led tracheostomy team is associated with shorter decannulation time and length of stay which may result in financial savings for institutions.