Chest
Volume 127, Issue 2, February 2005, Pages 598-603
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Clinical Investigations in Critical Care
Shock on Admission Day Is the Best Predictor of Prolonged Mechanical Ventilation in the ICU

https://doi.org/10.1378/chest.127.2.598Get rights and content

Study objectives

To determine the incidence of prolonged mechanical ventilation (PMV), which is associated with increased health-care costs and risks of adverse events, and to identify its early predictors.

Design

Retrospective cohort.

Setting

A medical-surgical ICU in a university-affiliated hospital.

Patients or participants

All patients admitted to the ICU over 3 years who received mechanical ventilation (MV) for > 12 h.

Interventions

None.

Measurements

PMV was defined as MV lasting > 21 days. We recorded epidemiologic data, severity scores, worst Pao2/fraction of inspired oxygen (Fio2), presence of shock on ICU admission day, cause for MV, length of MV, ICU length of stay (LOS), and hospital LOS. PMV patients were compared to patients weaned before 21 days (non-PMV group) to determine predictors of PMV.

Results

Of 551 hospital admissions, 319 patients (58%) required MV > 12 h. One hundred thirty patients died early and were excluded. Seventy-nine patients (14%) required PMV. The non-PMV group consisted of 110 patients. Simplified acute physiology score (SAPS) II, APACHE (acute physiology and chronic health evaluation) II, therapeutic intervention scoring system, Pao2/Fio2, shock, ICU LOS, and hospital LOS differed significantly between groups. However, logistic regression identified shock on ICU admission day as the only independent predictor of PMV (odds ratio, 3.10; p = 0.001). SAPS II and Pao2/Fio2 had the nearest coefficients and were used to build the predictive model. Sensitivity analysis was performed including the 130 patients who died early, and shock remained the most powerful predictor.

Conclusions

PMV was a frequent event in this cohort. The presence of shock on ICU admission day was the only prognostic factor, even adjusting for severity of illness and hypoxemia.

Section snippets

Materials and Methods

This retrospective cohort study took place in an eight-bed, mixed medical-surgical ICU in a university-affiliated hospital in La Plata, Buenos Aires, Argentina. Patients were admitted to the hospital from November 1, 1999, to October 31, 2002, and received MV for > 12 h. Patients were included only if intubation was performed in our ICU or in the operative room within a few hours after ICU admission. All data on these patients were prospectively collected as part of our ICU database.

On the day

Results

During the 3 years of our study, 551 patients were admitted to the ICU. Their mean age was 41 ± 17 years (± SD); 53% were men. Mean APACHE II and SAPS II scores were 18 ± 9 and 32 ± 18, respectively. The expected mortality rates were 31% and 28%, respectively, and the observed mortality rate was 31%.

Of the entire cohort, 348 patients (63%) received MV, and 319 patients (58%) received MV for > 12 h. Median length of MV was 7 days (interquartile range [IQR], 2 to 19 days). One hundred thirty

Discussion

As critical care is acutely directed at reversing a life-threatening condition, mortality is considered to be the primary outcome measure. However, morbidity outcomes also are relevant to patients, their families, health-care providers, and society as a whole. Recently, the importance of patient-centered outcomes has been emphasized, and long-term outcomes are considered important measurements.1314 The duration of MV, which is an indicator of serious health complications and significantly

ACKNOWLEDGMENT

We are indebted to Martha Swain for assistance in English editing of the manuscript.

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