CLINICAL PRACTICE

Physiological scoring systems and audit

This study was performed to develop and validate a cardiac surgical intensive care risk adjustment model for mixed cardiac surgery based on a few preoperative laboratory tests, extracorporeal circulation time, and measurements at arrival to the intensive care unit.

This was a retrospective study of admissions to 5 cardiac surgical intensive care units in Sweden that submitted data to the Swedish Intensive Care Registry. Admissions from 2008 to 2014 (n = 21,450) were used for model development, whereas admissions from 2015 to 2016 (n = 6463) were used for validation. Models were built using logistic regression with transformation of raw values or categorization into groups.

The final model showed good performance, with an area under the receiver operating characteristics curve of 0.86 (95% confidence interval, 0.83-0.89), a Cox calibration intercept of –0.16 (95% confidence interval, –0.47 to 0.19), and a slope of 1.01 (95% confidence interval, 0.89-1.13) in the validation cohort.

Eleven variables available on admission to the intensive care unit can be used to predict 30-day mortality after cardiac surgery. The model performance was better than those of general intensive care risk adjustment models used in cardiac surgical intensive care and also avoided the subjective assessment of the cause of admission. The standardized mortality ratio improves over time in Swedish cardiac surgical intensive care.

The aim of this study was to establish the profile and outcomes of paediatric major trauma care (PTMC) within an integrated inclusive regionalised trauma system.

Prospectively collected data from July 2001 to June 2009 from the Victorian State Trauma Registry of patients aged <18 years were reviewed.

There were 1634 major trauma cases with a median (IQR) age of 13 (6–16) years and 69% were male. The median ISS (IQR) was 18 (16–26). There were 1361 patients treated at a major trauma centre of which 69% (n = 943) were treated at the PMTC. Head injury (AIS > 2) was the most frequent injury (n = 950, 58%). Surgery was required in 39% (n = 637) of all cases; 437 patients in the 10–17 year old group and 200 patients in the 0–9 year old group; the mortality was 6.6%. There were 530 patients (32.4%) ventilated in ICU; these had a median ISS (IQR) of 25 (17–34) and mortality of 7.4%. Improvements in risk-adjusted mortality have occurred as the years have progressed [adjusted OR 95% CI: 0.87 (0.76, 0.99)] and being treated at a Level 1 trauma centre was associated with lower adjusted odds of mortality [adjusted OR 95% CI: 0.27 (0.11, 0.68)].

The establishment of this integrated inclusive regionalised trauma system has been associated with progressively improving risk-adjusted mortality. The relatively low volume of major trauma requiring surgery in the 0–9 year old age group is notable, creating a challenging environment for maintaining skills and institutional preparedness.

The aims of this study were to describe the demographics, injuries, mechanisms and severity of injury, prehospital and hospital care during the first 24 h, and patient outcome, in the most severely injured children cared for following trauma at a paediatric intensive care unit in Sweden.

The medical records of 131 traumatised children (0–16 years of age), admitted to the paediatric intensive care unit in Gothenburg from January 1990 to October 2000, were retrospectively examined. Nine internationally recognised scoring systems were used to calculate severity of injury, in order to predict the chances of patient survival.

Paediatric trauma was more common in boys (68%). The mean age at injury was 7.9 years (S.D. 4.7 years). Traffic-related accidents (40%) and falls (34%) were the leading causes of injury. Injuries to the head were the most frequent, forming 24% of all injuries. Severity of injury was recorded as an Injury Severity Score median of 14, Trauma Score Injury Severity Score median of 99% and Paediatric Risk of Mortality Score median of 0.69%. The mortality rate was 3%.

Trauma with admission to a paediatric intensive care unit is rare in a Swedish paediatric population. When cared for at a centre with the necessary facilities and trained personnel, these children have a good chance of survival.

To evaluate the validity of using the standardized mortality ratio (SMR) and the W statistic as risk-adjusted measures of hospital mortality to judge ICU performance.

APACHE (acute physiology and chronic health evaluation) II data were collected prospectively from the surgical ICU (SICU) at a single institution using all adult admissions (n = 6806) over an 8-year period (excluding cardiac surgical patients, burn patients, and patients under 16 years of age). Using a computer simulation technique, virtual ICUs (VICUs) with mortality rates between 5% and 16% were constructed. After first dividing the original data set into deciles of risk, each VICU was constructed by randomly resampling between 10 and 680 patients from each decile. The SMR, W statistic, and Z statistic were calculated for 10,000 different case mixes.

The SICU at a 450-bed teaching hospital.

A group of 6,806 adult patient admissions, excluding cardiac surgical patients and burn patients.

VICUs were created from a data set of actual patients treated at one institution in order to test the hypothesis that the SMR and W statistic would remain invariant when applied to subsets of patients from a single institution. Instead, the SMR and W statistic were found to be very sensitive to changes in case mix. The SMR and W statistic were linear functions of the simulated ICU mortality rate.

This simulation demonstrates that the SMR and the W statistic based on APACHE II cannot be used to compare outcomes of ICUs. We have proposed a revision of the SMR that eliminates the effect of case mix and allows for more accurate comparisons of ICU performance.