A comparison of three scoring systems for mortality risk among retrieved intensive care patients

Aims: To assess the impact of two paediatric intensive care unit retrieval teams on the performance of three mortality risk scoring systems: pre-ICU PRISM, PIM, and PRISM II. Methods: A total of 928 critically ill children retrieved for intensive care from district general hospitals in the south east of England (crude mortality 7.8%) were studied. Results: Risk stratification was similar between the two retrieval teams for scores utilising data primarily prior to ICU admission (pre-ICU PRISM, PIM), despite differences in case mix. The fewer variables required for calculation of PIM resulted in complete data collection in 88% of patients, compared to pre-ICU PRISM (24%) and PRISM II (60%). Overall, all scoring systems discriminated well between survival and non-survival (area under receiver operating characteristic curve 0.83–0.87), with no differences between the two hospitals. There was a tendency towards better discrimination in all scores for children compared to infants and neonates, and a poor discrimination for respiratory disease using pre-ICU PRISM and PRISM II but not PIM. All showed suboptimal calibration, primarily as a consequence of mortality over prediction among the medium (10–30%) mortality risk bands. Conclusions: PIM appears to offer advantages over the other two scores in terms of being less affected by the retrieval process and easier to collect. Recalibration of all scoring systems is needed.     

The Comparison of PRISM and PIM scoring systems for mortality risk in infantile intensive care

Scoring systems that predict the risk of mortality for children in an intensive care unit (ICU) are needed for the evaluation of the effectiveness of pediatric intensive care. The Pediatric Risk of Mortality (PRISM) and the Pediatric Index of Mortality (PIM) scores have been developed to predict mortality among children in the ICU. The purpose of this study was to evaluate whether these systems are effective and population-independent. PRISM and PIM scores were calculated prospectively during a 1-year period solely on 105 non-surgical infants admitted to the ICU. Statistical analysis was performed to assess the performance of the scoring systems. There were 29 (27.6 per cent) deaths and 76 (72.4 per cent) survivors. SMR and Z scores for PIM and PRISM signified higher mortality and poor performance. Prediction of mortality by the scoring systems appeared to be underestimated in almost all risk groups. The Hosmer and Lemeshow test showed a satisfactory overall calibration of both scoring systems. Although ROC analysis showed a poor discriminatory function of both scores, a marginally acceptable performance for PIM was observed. The ROC curve also showed an acceptable performance for PIM, for patients with pre-existent chronic disorder. Although care must be taken not to overstate the importance of our results, we believe that when revised according to the characteristics of the population, PIM may perform well in predicting the mortality risk for infants in the ICU, especially in countries where the mortality rate is relatively high and pre-existent chronic disorders are more common.     

False alarms in very low birthweight infants: comparison between three intensive care monitoring systems

Monitor alarms are a major burden on both patients and staff in intensive care units. We compared alarm rates from three different monitor systems (Hewlett Packard (HP), Kontron Instruments (KI), Marquette-Hellige (MH)) in a tertiary neonatal intensive care unit. Monitors were used in random order on three consecutive days over 8 h each in 16 preterm infants (median gestational age at birth 29 wk (range 24-34), age at study 18 d (8-53), weight at study 1,160g (595-1,430)). Alarms were classified as true or false using flow sheets based on continuous observation of both the patient and related parameters. There was one alarm every 9 min of monitoring. The median number of true alarms did not differ significantly between systems, being 28 per 8 h (range 9-87) for HP, 26 (3-81) for KI, and 30 (5-135) for MH. The median number of false alarms differed widely, with the HP system generating 32 (7-77) such alarms per 8 h, compared to 8 (0-19) for KI and 15 (2-32) for MH (p < 0.01 HP vs KI and MH, p < 0.05 KI vs MH). These differences between systems were mainly due to differences in pulse oximeter and transcutaneous PO2 monitor alarm rates. CONCLUSIONS: In conclusion, this study shows marked differences between both parameters and manufacturers in the frequency with which false alarms occur. It may provide a basis from which reductions in alarm rates can be sought.     

Application of different scoring systems and their value in pediatric intensive care unit

BackgroundLittle is known on the impact of risk factors that may complicate the course of critical illness. Scoring systems in ICUs allow assessment of the severity of diseases and predicting mortality.ObjectivesApply commonly used scores for assessment of illness severity and identify the combination of factors predicting patient’s outcome.MethodsWe included 231 patients admitted to PICU of Cairo University, Pediatric Hospital. PRISM III, PIM2, PEMOD, PELOD, TISS and SOFA scores were applied on the day of admission. Follow up was done using SOFA score and TISS.ResultsThere were positive correlations between PRISM III, PIM2, PELOD, PEMOD, SOFA and TISS on the day of admission, and the mortality rate (p < 0.0001). TISS and SOFA score had the highest discrimination ability (AUC: 0.81, 0.765, respectively). Significant positive correlations were found between SOFA score and TISS scores on days 1, 3 and 7 and PICU mortality rate (p < 0.0001). TISS had more ability of discrimination than SOFA score on day 1 (AUC: 0.843, 0.787, respectively).ConclusionScoring systems applied in PICU had good discrimination ability. TISS was a good tool for follow up. LOS, mechanical ventilation and inotropes were risk factors of mortality.     

Higher mortality rates among inborn infants admitted to neonatal intensive care units at night

OBJECTIVE: To examine circadian variation in deaths among infants < or =32 weeks' gestation admitted to Canadian neonatal intensive care units (NICU). STUDY DESIGN: We examined all infants (n=5192) between 24 and 32 weeks' gestation with complete data, who were admitted to 17 tertiary Canadian Neonatal Network NICUs from January 1996 to October 1997. Multivariable logistic regression was used to compare risk-adjusted early neonatal mortality rates (death within 7 days of NICU admission) of infants admitted during daytime (8 am to 5 pm) with infants admitted at night. RESULTS: Sixty percent (n=3131) of infants were admitted to the NICU at night. Patient risk factors significantly (P<.05) predictive of early neonatal death from multivariable logistic regression were male sex, outborn status, APGAR score <7 at 5 minutes, presence of congenital anomalies, low gestational age, and high admission Score for neonatal acute physiology, version II (SNAP-II). For inborn infants, in-house presence of a neonatal fellow or attending neonatologist at night (odds ratio, 0.6) and NICU admission at night (odds ratio, 1.6) were also predictive. CONCLUSIONS: Risk-adjusted early neonatal mortality odds was 60% higher among inborn infants < or =32 weeks' gestation admitted to NICUs at night compared with during daytime, equivalent to 29 excess deaths per 1000 infants.     

A comparison of pulmonary and femoral artery thermodilution cardiac indices in paediatric intensive care patients

We have assessed the agreement between pulmonary artery and femoral artery (COLD) thermodilution measurements of the cardiac index (C1) in a group of paediatric intensive care patients. The COLD method gave consistently higher cardiac index values than the pulmonary artery catheter (PAC); however, the difference was small, with a mean value of 0.191/min⁻¹ m⁻² or 4.4% of the mean cardiac index. This difference is not clinically important and suggests that, under these circumstances. the COLD system provides an acceptable alternative to the pulmonary artery catheter for measurement of the cardiac index at the bedside.     

Epidemiology and diagnosis of hospital-acquired conjunctivitis among neonatal intensive care unit patients

BACKGROUND: Few recent reports describe the epidemiology and risk factors for health care-associated conjunctivitis among neonatal intensive care unit (NICU) patients in developed countries. Reporting may be inaccurate in this population given that the National Nosocomial Infection Surveillance System (NNIS) definition is largely dependent on a positive culture, whereas clinical practice often consists of empiric treatment. OBJECTIVES: We describe the epidemiology of conjunctivitis among neonates in 2 level III-IV NICUs and compare the NNIS definition with our study definition: eye drainage and empiric treatment with or without a culture. METHODS: Patient demographics, clinical, device usage and conjunctivitis data collected prospectively from March 2001 through January 2003 were analyzed. RESULTS: Conjunctivitis occurred in 5% (n = 154/2935) of infants, of whom 51% (n =79) were in NICU 1 and 49% (n =75) in NICU 2. Predominant pathogens included coagulase-negative staphylococci (25%), Staphylococcus aureus (19%) and Klebsiella spp. (10%). Significant predictors of conjunctivitis included low birth weight, use of ventilator or nasal cannula continuous positive airway pressure and study year. Ophthalmologic examination was an additional predictor of infection in NICU 1. Eye examination data were unavailable for NICU 2. Only 62% of cases that met the study definition for conjunctivitis met the NNIS definition, because many infants received empiric treatment. CONCLUSIONS: Clinical conjunctivitis was associated with low birth weight and patient care factors that could lead to contamination of the eye with respiratory tract secretions. The NNIS definition failed to detect 38% of clinical infections. Consideration should be given to revising the definition of conjunctivitis for the NICU population.     

Prediction of mortality by application of PRISM score in intensive care unit.

OBJECTIVE: Prediction of mortality by application of Pediatric Risk of Mortality (PRISM) score in Pediatric Intensive Care Unit (PICU) patients under Indian circumstances. DESIGN: Prospective study. SETTING: PICU of a tertiary care multi-specialty hospital. METHODS: 100 sick pediatric patients admitted consecutively in PICU were taken for this study. PRISM score was calculated. Hospital outcome was recorded as (died/survived). The predicted death was calculated by the formula: RESULTS: Of 100 patients, 18 died and 82 survived. By PRISM score 49 children had the score of 1-9. The expected death in this group was 10.3% (n = 5.03) and the observed death was 8.2% (n = 4). Among 45 children with the score of 10-19, the expected mortality was 21.2% (n = 9.6) and observed was 24.4% (n = 11). There were 3 patients with the score of 20-29, the expected mortality in this group was 39.3% (n = 1.18) and observed mortality 33.3% (n = 1). There were 3 patients with score > or = 30, observed death 66.3% (n = 2) and expected mortality was 74.7% (n = 2.24). There was no significant difference between expected and observed mortality in any group. (p > 0.5). ROC analysis showed area under the curve of 72%. CONCLUSION: PRISM score has good predictive value in assessing the probability of mortality in relation to children admitted to a PICU under Indian circumstances.     

A national study of risk factors associated with mortality in very low birthweight infants in the Malaysian neonatal intensive care units

To determine the risk factors associated with mortality in very low birthweight (VLBW) infants admitted to the neonatal intensive care units (NIUC) in Malaysia.

Method:

A prospective observational study of outcome of all VLBW infants born between 1 January 1993 and 30 June 1993 and admitted to the NICU.

Results:

Data of 868 VLBW neonates from 18 centres in Malaysia were collected. Their mean birthweight was 1223 g (95% confidence intervals: 1208–1238 g). Thirty-seven point four per cent (325/868) of these infants died before discharge. After exclusion of all infants with congenital anomalies ( n =66, and nine of them also had incomplete records) and incomplete records ( n =82), stepwise logistic regression analysis of the remaining 720 infants showed that the risk factors that were significantly associated with increased mortality before discharge were: delivery in district hospitals, Chinese race, lower birthweight, lower gestation age, persistent pulmonary hypertension of the newborn, pulmonary airleak, necrotizing enterocolitis of stage 2 or 3, confirmed sepsis, hypotension, hypothermia, acute renal failure, intermittent positive pressure ventilation, and umbilical arterial catheterization. Factors that were significantly associated with lower risk of mortality were: use of antenatal steroid, oxygen therapy, surfactant therapy and blood transfusion.

Conclusion:

The mortality of VLBW infants admitted to the Malaysian NICU was high and was also associated with a number of preventable risk factors.     

Glucose control, organ failure, and mortality in pediatric intensive care.

OBJECTIVE: In ventilated children, to determine the prevalence of hyperglycemia, establish whether it is associated with organ failure, and document glycemic control practices in Australasian pediatric intensive care units (PICUs). DESIGN: Prospective inception cohort study. SETTING: All nine specialist PICUs in Australia and New Zealand. PATIENTS: Children ventilated > 12 hrs excluding those with diabetic ketoacidosis, on home ventilation, undergoing active cardiopulmonary resuscitation on admission, or with do-not-resuscitate orders. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All blood glucose measurements for up to 14 days, clinical and laboratory values needed to calculate Paediatric Logistic Organ Dysfunction (PELOD) scores, and insulin use were recorded in 409 patients. Fifty percent of glucose measurements were > 6.1 mmol/L, with 89% of patients having peak values > 6.1 mmol/L. The median time to peak blood glucose was 7 hrs. Hyperglycemia was defined by area under the glucose-time curve > 6.1 mmol/L above the sample median. Thirteen percent of hyperglycemic subjects died vs. 3% of nonhyperglycemic subjects. There was an independent association between hyperglycemia and a PELOD score > or = 10 (odds ratio 3.41, 95% confidence interval 1.91-6.10) and death (odds ratio 3.31, 95% confidence interval 1.26-7.7). Early hyperglycemia, defined using only glucose data in the first 48 hrs, was also associated with these outcomes but not with PELOD > or = 10 after day 2 or with worsening PELOD after day 1. Five percent of patients received insulin. CONCLUSIONS: Hyperglycemia is common in PICUs, occurs early, and is independently associated with organ failure and death. However, early hyperglycemia is not associated with later or worsening organ failure. Australasian PICUs seldom use insulin.     

Calibration of the paediatric index of mortality in UK paediatric intensive care units.

AIM: To test a paediatric intensive care mortality prediction model for UK use. METHOD: Prospective collection of data from consecutive admissions to five UK paediatric intensive care units (PICUs), representing a broad cross section of paediatric intensive care activity. A total of 7253 admissions were analysed using tests of the discrimination and calibration of the logistic regression equation. RESULTS: The model discriminated and calibrated well. The area under the ROC plot was 0.84 (95% CI 0.819 to 0.853). The standardised mortality ratio was 0.87 (95% CI 0.81 to 0.94). There was remarkable concordance in the performance of the paediatric index of mortality (PIM) within each PICU, and in the performance of the PICUs as assessed by PIM. Variation in the proportion of admissions that were ventilated or transported from another hospital did not affect the results. CONCLUSION: We recommend that UK PICUs use PIM for their routine audit needs. PIM is not affected by the standard of therapy after admission to PICU, the information needed to calculate PIM is easy to collect, and the model is free.     

Enhanced thrombin generation in patients receiving intensive care.

Thrombin-antithrombin III complex (TAT) concentration was measured in 27 control and 155 intensive care patients to (a) establish normal reference ranges, (b) measure thrombin generation in critically ill patients, and (c) determine the characteristics of the TAT assay for the diagnosis of disseminated intravascular coagulation (DIC) in children. The normal reference range was 1-4.3 micrograms/l (median 2.3 micrograms/l), and 89.7% of patients had raised TAT concentrations. Median TAT concentrations in the presence of DIC (27 micrograms/l) were significantly higher than in its absence (8 micrograms/l). Sensitivity, specificity, and positive and negative predictive values of the assay were 97.3%, 28.3%, 76.3%, and 81.3%, respectively, at a cut off of 4 micrograms/l. Excess thrombin production occurs in the majority of critically ill children. The TAT assay is potentially useful in the diagnosis of DIC in children.     

Determinants of death among admissions to intensive care unit for newborns

Determinants of death in newborns admitted to the Intensive Care Unit were studied taking into consideration antenatal history, intrapartum events, and clinical findings. Over 3 years (1984, 1985 and 1986) 1747 admissions were the subjects of this study. Of these, 424 deaths formed the study group and 1323 survivors form the control group. Odds ratio, attributable risk, univariate analysis, multiple stepwise regression, and analysis of variance were obtained. Clinical features associated with respiratory distress, birth asphyxia, admission to nursery after 6 hours of birth, and hypothermia on admission were found to be important factors related to death among nursery admissions.