Anthony R. Brady

Epidemiology of severe sepsis occurring in the first 24 hrs in intensive care units in england, Wales, and Northern Ireland

ObjectiveTo investigate the numbers, clinical characteristics, resource use, and outcomes of admissions who met precise clinical and physiologic criteria for severe sepsis (as defined in the PROWESS trial) in the first 24 hrs in the intensive care unit. DesignObservational cohort study, with retrospective analysis of prospectively collected data. SettingNinety-one adult general intensive care units in England, Wales, and Northern Ireland between 1995 and 2000. PatientsPatients were 56,673 adult admissions. InterventionsNone. Measurements and Main ResultsWe found that 27.1% of adult intensive care unit admissions met severe sepsis criteria in the first 24 hrs in the intensive care unit. Most were nonsurgical (67%), and the most common organ system dysfunctions were seen in the cardiovascular (88%) and respiratory (81%) systems. Modeling the data for England and Wales for 1997 suggested that 51 (95% confidence interval, 46–58) per 100,000 population per year were admitted to intensive care units and met severe sepsis criteria in the first 24 hrs.Of the intensive care unit admissions who met severe sepsis criteria in the first 24 hrs, 35% died before intensive care unit discharge and 47% died during their hospital stay. Hospital mortality rate ranged from 17% in the 16–19 age group to 64% in those >85 yrs. In England and Wales in 1997, an estimated 24 (95% confidence interval, 21–28) per 100,000 population per year died after intensive care unit admissions with severe sepsis in the first 24 hrs.For intensive care unit admissions who met severe sepsis criteria in the first 24 hrs, median intensive care unit length of stay was 3.56 days (interquartile range, 1.50–9.32) and median hospital length of stay was 18 days (interquartile range, 8–36 days). These admissions used 45% of the intensive care unit and 33% of the hospital bed days used by all intensive care unit admissions. ConclusionsSevere sepsis is common and presents a major challenge for clinicians, managers, and healthcare policymakers. Intensive care unit admissions meeting severe sepsis criteria have a high mortality rate and high resource use.

Randomised controlled trial assessing the impact of a nurse delivered, flow monitored protocol for optimisation of circulatory status after cardiac surgery

Abstract Objective To assess whether a nurse led, flow monitored protocol for optimising circulatory status in patients after cardiac surgery reduces complications and shortens stay in intensive care and hospital. Design Randomised controlled trial. Setting Intensive care unit and cardiothoracic unit of a university teaching hospital. Participants 174 patients who underwent cardiac surgery between April 2000 and January 2003. Interventions Patients were allocated to conventional haemodynamic management or to an algorithm guided by oesophageal Doppler flowmetry to maintain a stroke index above 35 ml/m2. Results 26 control patients had postoperative complications (two deaths) compared with 17 (four deaths) protocol patients (P = 0.08). Duration of hospital stay in the protocol group was significantly reduced from a median of nine (interquartile range 7-12) days to seven (7-10) days (P = 0.02). The mean duration of hospital stay was reduced from 13.9 to 11.4 days, a saving in hospital bed days of 18% (95% confidence interval −12% to 47%). Usage of intensive care beds was reduced by 23% (−8% to 59%). Conclusion A nurse delivered protocol for optimising circulatory status in the early postoperative period after cardiac surgery may significantly shorten hospital stay.

Recalibration of risk prediction models in a large multicenter cohort of admissions to adult, general critical care units in the United Kingdom.

Objective:To assess the performance of published risk prediction models in common use in adult critical care in the United Kingdom and to recalibrate these models in a large representative database of critical care admissions. Design:Prospective cohort study. Setting:A total of 163 adult general critical care units in England, Wales, and Northern Ireland, during the period of December 1995 to August 2003. Patients:A total of 231,930 admissions, of which 141,106 met inclusion criteria and had sufficient data recorded for all risk prediction models. Interventions:None. Measurements and Main Results:The published versions of the Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE II UK, APACHE III, Simplified Acute Physiology Score (SAPS) II, and Mortality Probability Models (MPM) II were evaluated for discrimination and calibration by means of a combination of appropriate statistical measures recommended by an expert steering committee. All models showed good discrimination (the c index varied from 0.803 to 0.832) but imperfect calibration. Recalibration of the models, which was performed by both the Cox method and re-estimating coefficients, led to improved discrimination and calibration, although all models still showed significant departures from perfect calibration. Conclusions:Risk prediction models developed in another country require validation and recalibration before being used to provide risk-adjusted outcomes within a new country setting. Periodic reassessment is beneficial to ensure calibration is maintained.

Assessment and Optimization of Mortality Prediction Tools for Admissions to Pediatric Intensive Care in the United Kingdom

OBJECTIVE. To assess the Pediatric Risk of Mortality (PRISM, PRISM III-12, and PRISM III-24) systems and the Pediatric Index of Mortality (PIM and PIM2) systems for use in comparing the risk-adjusted mortality of children after admission for pediatric intensive care in the United Kingdom. METHODS. All PICUs in the United Kingdom were invited to participate. Predicted probability of PICU mortality was calculated using the published algorithms for PIM, PIM2, and PRISM and compared with observed mortality. These scores, along with PRISM III-12 and PRISM III-24, whose algorithms are not published, were optimized for the United Kingdom. RESULTS. Of 26 PICUs in the United Kingdom, 22 (85%) were recruited, and sufficient prospective data were collected from 18 (69%) units on 10197 (98%) of 10385 admissions between March 2001 and February 2002. All published tools were found to have poor calibration but provided good discriminatory power. After estimation of UK-specific coefficients, only PIM2, PRISM III-12, and PRISM III-24 had satisfactory calibration. All models provided good discriminatory power. Funnel plots for all of the recalibrated models indicated that the risk-adjusted mortality for all units was consistent with random variation. CONCLUSIONS. PIM2, PRISM III-12, and PRISM III-24 all were found to be suitable for use in a UK PICU setting. All tools provided similar conclusions in assessing the distribution of risk-adjusted mortality in UK PICUs. It now is important that these tools be used to monitor outcome and improve the quality of pediatric intensive care within the United Kingdom.

Case mix, outcome and activity for obstetric admissions to adult, general critical care units: a secondary analysis of the ICNARC Case Mix Programme Database

IntroductionRisk prediction scores usually overestimate mortality in obstetric populations because mortality rates in this group are considerably lower than in others. Studies examining this effect were generally small and did not distinguish between obstetric and nonobstetric pathologies. We evaluated the performance of the Acute Physiology and Chronic Health Evaluation (APACHE) II model in obstetric admissions to critical care units contributing to the ICNARC Case Mix Programme.MethodsAll obstetric admissions were extracted from the ICNARC Case Mix Programme Database of 219,468 admissions to UK critical care units from 1995 to 2003 inclusive. Cases were divided into direct obstetric pathologies and indirect or coincidental pathologies, and compared with a control cohort of all women aged 16–50 years not included in the obstetric categories. The predictive ability of APACHE II was evaluated in the three groups. A prognostic model was developed for direct obstetric admissions to predict the risk for hospital mortality. A log-linear model was developed to predict the length of stay in the critical care unit.ResultsA total of 1452 direct obstetric admissions were identified, the most common pathologies being haemorrhage and hypertensive disorders of pregnancy. There were 278 admissions identified as indirect or coincidental and 22,938 in the nonpregnant control cohort. Hospital mortality rates were 2.2%, 6.0% and 19.6% for the direct obstetric group, the indirect or coincidental group, and the control cohort, respectively. Cox regression calibration analysis showed a reasonable fit of the APACHE II model for the nonpregnant control cohort (slope = 1.1, intercept = -0.1). However, the APACHE II model vastly overestimated mortality for obstetric admissions (mortality ratio = 0.25). Risk prediction modelling demonstrated that the Glasgow Coma Scale score was the best discriminator between survival and death in obstetric admissions.ConclusionThis study confirms that APACHE II overestimates mortality in obstetric admissions to critical care units. This may be because of the physiological changes in pregnancy or the unique scoring profile of obstetric pathologies such as HELLP syndrome. It may be possible to recalibrate the APACHE II score for obstetric admissions or to devise an alternative score specifically for obstetric admissions.

Socioeconomic Status and Outcome From Intensive Care in England and Wales

Objective:The objective of this study was to estimate the association between socioeconomic status (SES) and outcome for admissions to intensive care. Research Design:Retrospective cohort study. Subjects:We studied 51,572 admissions to 99 intensive-care units in England and Wales between 1995 and 2000. Measures:The SES of admissions was measured using Carstairs deprivation scores. Outcome was hospital mortality after adjustment for case mix using the APACHE II method. Results:Admissions of lower SES were, on average, younger and less likely to be following surgery. There was evidence of a SES gradient for hospital mortality in admissions after elective surgery after adjusting for case mix (test for trend P <0.001), with higher SES associated with lower mortality. In the least-deprived quintile of SES, the odds ratio for hospital mortality was 0.70 (95% confidence interval, 0.58–0.84) compared with the most deprived quintile. There was no evidence of a SES gradient for hospital mortality in nonsurgical or emergency surgical admissions, and the decision to withdraw active treatment did not differ by SES. Conclusions:There is a SES gradient for hospital mortality in elective surgical admissions that is not explained by differences in case mix or the withdrawal of active treatment. Further research is required to establish if this finding can be explained by unmeasured differences in health status at admission to an intensive-care unit or differences in care and to establish the potential impact these results may have on interpreting comparative surgical performance data.

Winter excess mortality in intensive care in the UK: an analysis of outcome adjusted for patient case mix and unit workload

ObjectiveTo investigate whether mortality in UK intensive care units is higher in winter than in non-winter and to explore the importance of variations in case mix and increased pressure on ICUs.Design and settingCohort study in 115 adult, general ICUs in England, Wales and Northern Ireland.Patients and participants113,389 admissions from 1995 to 2000.Measurements and resultsHospital mortality following admission to ICU was compared between winter (December–February) and non-winter (March–November). The causes of any observed differences were explored by adjusting for the case mix of admissions and the workload of the ICUs. Crude hospital mortality was higher in winter. After adjusting for case mix using the APACHE II mortality probability this effect was reduced but still significant. When additional factors reflecting case mix and workload were introduced into the model, the overall effect of winter admission was no longer significant. Factors reflecting both the case mix of the individual patient and of the patients in surrounding beds were found to be significantly associated with outcome. After adjustment for other factors, the occupancy of the unit (proportion of beds occupied) was not significantly associated with mortality.ConclusionsThe excess winter mortality observed in UK ICUs can be explained by variation in the case mix of admissions. Unit occupancy was not associated with mortality.

Case mix and outcomes for admissions to UK adult, general critical care units with chronic obstructive pulmonary disease: a secondary analysis of the ICNARC Case Mix Programme Database

IntroductionChronic obstructive pulmonary disease (COPD) is a common cause of admission to intensive care units (ICUs) in the UK. This report describes the case mix and outcomes of these patients and explores associations of measures of case mix available in the first 24 hours with outcome.MethodWe conducted a secondary analysis of a high quality clinical database, the ICNARC Case Mix Programme Database, of 129,647 admissions to 128 adult, general critical care units across England, Wales and Northern Ireland for the period from 1995 to 2001.ResultsNonsurgical admissions with COPD accounted for 3752 admissions (2.9% of all admissions). Patients were acidotic (median pH 7.26, interquartile range [IQR] 7.18–7.33), hypercapnic (median arterial CO2 tension 8.7, IQR 6.9–10.7) and hypoxic (median arterial O2 tension/fractional inspired oxygen gradient 22.9, IQR 17.2–29.6). Overall, 2775 (73.9%) were definitely intubated and 278 (7.4%) were probably intubated in the first 24 hours in the ICU. The median (IQR) ICU length of stay was 4.0 (1.6–9.4) days and the hospital length of stay was 16 (9–29) days. a total of 827 patients (23.1%) died in the admitting ICU and 1322 (38.3%) died during hospital admission. Age, presence of severe respiratory disease, length of stay in hospital before critical care admission, cardiopulmonary resuscitation within 24 hours before admission, intubation status in first 24 hours in critical care, pH, arterial oxygen tension/fractional inspired oxygen gradient, albumin, cardiovascular organ failure, neurological organ failure and renal organ failure all had independent associations with hospital mortality. Respiratory organ failure had a significant independent association with decreased hospital mortality.ConclusionNonsurgical patients with COPD represent an important group of patients admitted to UK ICUs. The presence of single organ respiratory failure in the first 24 hours in critical care identifies patients with a 70% chance of surviving to leave hospital.

Hospitals' star ratings and clinical outcomes: ecological study

The English Department of Health is developing global measures of the performance of all NHS bodies, including 166 acute hospital trusts. Since 2000-1, the trusts get zero, one, two, or three stars to indicate performance.1 This rating may not reflect the effectiveness of clinical care measured in patient outcomes because of the lack of accurate routine data.2 One exception is in adult critical care3; we checked whether a hospitals rating provided an indication of its clinical outcomes. We compared the 2001-2 rating of 102 acute hospital trusts for which we had validated data for that year. We calculated each patients predicted risk of death before discharge from hospital4 and compared it with actual mortality for all admissions in 2001-2 for each unit. We compared rating with crude mortality at the patient level rather than aggregated by hospital; our sample …