Retrospective analysis of critically ill patients with severe acute respiratory syndrome admitted to an intensive care unit

Introduction

Severe acute respiratory syndrome (SARS) is a new infectious disease that presented in Southern China in late 2002. On 26 March 2003, Princess Margaret Hospital (PMH) was designated as the receiving hospital for all SARS cases in Hong Kong. Shortly after, there was a massive upsurge in the number of cases as a result of the rapid spread of SARS through a residential block. Over 600 cases of suspected SARS were admitted to PMH in the first week of April, 409 of whom were confirmed with SARS. Within 2 weeks the hospital was unable to cope. Great difficulty was encountered in mobilizing sufficient trained ICU staff in addition to the extra ICU beds required.

SARS is a syndrome that can progress to respiratory failure and death. Chest radiographs are abnormal in the majority of patients and demonstrate variable infiltrative patterns. Clinical deterioration is accompanied by progression of pulmonary infiltrate. Early experience suggested that approximately 20% of cases require admission to an intensive care unit (ICU) as a result of respiratory failure.

Objective

This study aimed to describe patients with SARS who developed respiratory failure requiring ICU admission.

Methods

Retrospective analysis of prospectively collected demographic, clinical, biochemical, microbiological and radiological data on SARS cases admitted to an ICU.

Results

A total of 116 patients, including 10 health care workers, were admitted to the ICU with a clinical diagnosis of SARS. In 62% of cases, SARS Co-V was positive. The mean time interval between symptom onset and hospital admission was 4.8 ± 3.7 days and the mean time between symptom onset and ICU admission was 10.5 ± 4.7 days. The 116 patients had a mean ± SD age of 48.2 ± 14.6 (range 24 to 96) years. Sixty-eight percent had known contact or exposure to another SARS person. Significant comorbidity was present in 36%. Treatment consisted of broad-spectrum antibiotics, ribavarin, corticosteroids (maintenance and pulse), and in selected cases kaletra, immunoglobulin, convalescent serum and Chinese herbal medicine. The median Acute Physiology and Chronic Health Evaluation II score was 19 (range 6–49). The admission mean ratio of the partial pressure of oxygen to the fraction of inspired oxygen was 146 ± 80 (range 60–421). Seventy-six patients required mechanical ventilation and the mortality in this group was 53%. No spontaneously breathing patients died while in the ICU. Of the ventilated patients, 28% developed barotrauma. In the nonventilated patients, 10% developed barotrauma spontaneously. Renal failure occurred in 78% of nonsurvivors and 8% of survivors. Positive blood cultures occurred in 37% of nonsurvivors and 8% of survivors. The median duration of stay in the ICU was 13 days (range <1 to 111 days). The overall mortality was 34.5%.

Conclusion

SARS carries a high mortality especially in mechanically ventilated patients. Barotrauma, renal failure and sepsis were prevalent.