Risk factors for the misdiagnosis of pneumothorax in the intensive care unit.

OBJECTIVE

To identify risk factors predisposing to the misdiagnosis of pneumothorax in the ICU.

DESIGN

A prospective case series investigation.

SETTING

A medical ICU service of a military referral hospital.

PATIENTS

All adult medical ICU patients were evaluated during a 12-month period. Of 464 admissions, 28 (6%) were found to have acquired a pneumothorax during their medical ICU stay.

INTERVENTIONS

Nineteen (67.9%) patients with pneumothorax were diagnosed correctly on initial presentation of their pneumothorax. The remaining nine (32.1%) patients' pneumothoraces were misdiagnosed at initial presentation.

MEASUREMENTS AND MAIN RESULTS

Tension pneumothorax occurred more frequently in patients with an initially misdiagnosed pneumothorax (33.3%) than in patients with pneumothoraces that were correctly diagnosed during their medical ICU stay (5.3%) (p less than .06). Thirteen variables chosen prospectively were examined using a chi-square statistic. The following four variables occurred statistically more often in nine patients with an initially misdiagnosed pneumothorax: a) mechanical ventilation required at the time of the development of pneumothorax (p less than .05); b) an atypical radiographic location of the pneumothorax (p less than .05); c) altered mental status exhibited at the time of pneumothorax presentation (p less than .05); and d) development of pneumothorax after peak physician staffing hours (p less than .02).

CONCLUSIONS

Certain medical ICU patients appear to be at higher risk for the initial misdiagnosis of pneumothorax. Familiarity with factors predisposing to this problem should allow for a higher index of suspicion for the diagnosis of pneumothorax in critically ill patients and possibly improve the early detection of pneumothorax.