Lead time bias and standardised mortality ratios in intensive care patients

Objective Determine if the shortest sampling interval for laboratory variables used to estimate baseline severity of illness in pediatric critical care is equivalently sensitive across multiple sites without site-specific bias, while accounting for the vast majority of dysfunction compared to the standard 0 hour to 12 hour Pediatric Risk of Mortality (PRISM) III score. Design Prospective, random patient selection. Setting General/Medical and Cardiac/Cardiovascular pediatric intensive care units (PICUs) in 8 hospitals. Patients Patients < 18 years admitted to the PICU. Interventions None. Measurements and Main Results A total of 376 patients were included. Measurements for PRISM III laboratory variables (pH, PCO2, total CO2, PaO2, glucose, potassium, blood urea nitrogen (BUN), creatinine, total (WBC) count, platelet count, PT/PTT) were recorded from 2 hours prior to the PICU admission through 12 hours of the PICU care except for data in the operating room. Decreasing the observation period from the 0 hour to 12 hours post-PICU admission resulted in progressive decreases in the PRISM III laboratory variables measured. However, allowing the observation period to start 2 hours prior to PICU admission to 4 hours reduced this loss to only 3.4%. Similar trends existed for each of the individual laboratory PRISM III variables. There was a nearly identical distribution of laboratory PRISM III points within the −2 hour to 4 hour period compared to the standard period. We did not detect any institutional bias using the −2 hour to 4 hour time period compared to the baseline. Conclusions Prognostically important laboratory physiologic data collected within the interval from two hours prior to PICU to admission through four hours after admission account for the vast majority of dysfunction that these variables would contribute to PRISM III scores. There was no institutional bias associated with this sampling period.

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“…1–5 . First, the assessment period should be sufficiently long to enable the assessment of prognostically important physiological variables.…”

Section: Introductionmentioning

confidence: 99%

The Ideal Time Interval for Critical Care Severity-of-Illness Assessment

Pollack

Dean

Butler

et al. 2013

Pediatric Critical Care Medicine

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“…In emergencies that occur in intensive care units, medical assessments should be performed under extreme time constraints (Nielsen, Woodcock, Nolan, & Jonas, 1999;Tunnell, Millar, & Smith, 1998;Vincent, & Moreno, 2010). To provide the appropriate intervention level it is crucial that the assessments shall be accurate (Greenland et al, 2007;Thompson et al, 2009;Benner, Hughes, & Sutphen, 2008).…”

Section: Introductionmentioning

confidence: 99%

Using Video Recorded Neonatal Intensive Care Unit Scenarios to Test Agreement between Clinicians’ Assessments

Nadler

Globus

Pessach-Gelblum

et al. 2014

Proceedings of the Human Factors and Ergonomics Society Annual

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Clinicians in Neonatal Intensive Care Units are required to perform assessments under extreme pressure to determine the illness severity of neonates. Currently there is no reference that indicates the clinical condition of a neonate according to its vital signs. Agreement between clinicians' assessments can provide initial indication for the clinicians' ability to systematically perform assessments. Agreement was tested between 16 clinicians who viewed 31 recorded cases and scored the illness severity of a neonate mannequin in each case. The agreement level was fair (0.28), but high correlation between the assessments (0.8

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A retrospective observational study of drotrecogin alfa (activated) in adults with severe sepsis: Comparison with a controlled clinical trial*

Wheeler

Steingrub

Schmidt

et al. 2008

Critical Care Medicine

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Patients treated in clinical practice differed from those in PROWESS. Patients were younger, had more comorbidities, had greater severity of illness, and had longer mean time from severe sepsis onset to the start of DrotAA. Hospital mortality for patients treated within 1 day of severe sepsis onset was similar to DrotAA-treated PROWESS patients. While the low number of serious bleeding events precludes a definitive assessment, the observed incidence of serious bleeding events in clinical practice patients was numerically higher than in DrotAA-treated PROWESS patients.

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Lead time bias and standardised mortality ratios in intensive care patients

Cited by 3 publications

References 3 publications

The Ideal Time Interval for Critical Care Severity-of-Illness Assessment

The Ideal Time Interval for Critical Care Severity-of-Illness Assessment

Using Video Recorded Neonatal Intensive Care Unit Scenarios to Test Agreement between Clinicians’ Assessments

A retrospective observational study of drotrecogin alfa (activated) in adults with severe sepsis: Comparison with a controlled clinical trial*

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