Non-invasive versus invasive mechanical ventilation for respiratory failure in severe acute respiratory syndrome.

BACKGROUND: Severe acute respiratory syndrome is frequently complicated by respiratory failure requiring ventilatory support. We aimed to compare the efficacy of non-invasive ventilation against invasive mechanical ventilation treating respiratory failure in this disease. METHODS: Retrospective analysis was conducted on all respiratory failure patients identified from the Hong Kong Hospital Authority Severe Acute Respiratory Syndrome Database. Intubation rate, mortality and secondary outcome of a hospital utilizing non-invasive ventilation under standard infection control conditions (NIV Hospital) were compared against 13 hospitals using solely invasive ventilation (IMV Hospitals). Multiple logistic regression analyses with adjustments for confounding variables were performed to test for association between outcomes and hospital groups. RESULTS: Both hospital groups had comparable demographics and clinical profiles, but NIV Hospital (42 patients) had higher lactate dehydrogenase ratio and worse radiographic score on admission and ribavirin-corticosteroid commencement. Compared to IMV Hospitals (451 patients), NIV Hospital had lower adjusted odds ratios for intubation (0.36, 95% CI 0.164 - 0.791, P = 0.011) and death (0.235, 95% CI 0.077 - 0.716, P = 0.011), and improved earlier after pulsed steroid rescue. There were no instances of transmission of severe acute respiratory syndrome among health care workers due to the use of non-invasive ventilation. CONCLUSION: Compared to invasive mechanical ventilation, non-invasive ventilation as initial ventilatory support for acute respiratory failure in the presence of severe acute respiratory syndrome appeared to be associated with reduced intubation need and mortality.

Effectiveness of noninvasive positive pressure ventilation in the treatment of acute respiratory failure in severe acute respiratory syndrome.

OBJECTIVES: To study the effectiveness of noninvasive positive pressure ventilation (NIPPV) in the treatment of acute respiratory failure (ARF) in severe acute respiratory syndrome (SARS), and the associated infection risk. METHODS: All patients with the diagnosis of probable SARS admitted to a regional hospital in Hong Kong from March 9 to April 28, 2003, and who had SARS-related respiratory distress complications were recruited for NIPPV usage. The health status of all health-care workers working in the NIPPV wards was closely monitored, and consent was obtained to check serum for coronavirus serology. Patient outcomes and the risk of SARS transmission to health-care workers were assessed. RESULTS: NIPPV was applied to 20 patients (11 male patients) with ARF secondary to SARS. Mean age was 51.4 years, and mean acute physiology and chronic health evaluation II score was 5.35. Coronavirus serology was positive in 95% (19 of 20 patients). NIPPV was started 9.6 days (mean) from symptom onset, and mean duration of NIPPV usage was 84.3 h. Endotracheal intubation was avoided in 14 patients (70%), in whom the length of ICU stay was shorter (3.1 days vs 21.3 days, p < 0.001) and the chest radiography score within 24 h of NIPPV was lower (15.1 vs 22.5, p = 0.005) compared to intubated patients. Intubation avoidance was predicted by a marked reduction in respiratory rate (9.2 breaths/min) and supplemental oxygen requirement (3.1 L/min) within 24 h of NIPPV. Complications were few and reversible. There were no infections among the 105 health-care workers caring for the patients receiving NIPPV. CONCLUSIONS: NIPPV was effective in the treatment of ARF in the patients with SARS studied, and its use was safe for health-care workers.

Development of a standard treatment protocol for severe acute respiratory syndrome.

A series of 31 patients with probable SARS, diagnosed from WHO criteria, were treated according to a treatment protocol consisting of antibacterials and a combination of ribavirin and methylprednisolone. Through experience with the first 11 patients, we were able to finalise standard dose regimens, including pulsed methylprednisolone. One patient recovered on antibacterial treatment alone, 17 showed rapid and sustained responses, and 13 achieved improvement with step-up or pulsed methylprednisolone. Four patients required short periods of non-invasive ventilation. No patient required intubation or mechanical ventilation. There was no mortality or treatment morbidity in this series.

A cluster of cases of severe acute respiratory syndrome in Hong Kong.

BACKGROUND: Information on the clinical features of the severe acute respiratory syndrome (SARS) will be of value to physicians caring for patients suspected of having this disorder. METHODS: We abstracted data on the clinical presentation and course of disease in 10 epidemiologically linked Chinese patients (5 men and 5 women 38 to 72 years old) in whom SARS was diagnosed between February 22, 2003, and March 22, 2003, at our hospitals in Hong Kong, China. RESULTS: Exposure between the source patient and subsequent patients ranged from minimal to that between patient and health care provider. The incubation period ranged from 2 to 11 days. All patients presented with fever (temperature, >38 degrees C for over 24 hours), and most presented with rigor, dry cough, dyspnea, malaise, headache, and hypoxemia. Physical examination of the chest revealed crackles and percussion dullness. Lymphopenia was observed in nine patients, and most patients had mildly elevated aminotransferase levels but normal serum creatinine levels. Serial chest radiographs showed progressive air-space disease. Two patients died of progressive respiratory failure; histologic analysis of their lungs showed diffuse alveolar damage. There was no evidence of infection by Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella pneumophila. All patients received corticosteroid and ribavirin therapy a mean (+/-SD) of 9.6+/-5.42 days after the onset of symptoms, and eight were treated earlier with a combination of beta-lactams and macrolide for 4+/-1.9 days, with no clinical or radiologic efficacy. CONCLUSIONS: SARS appears to be infectious in origin. Fever followed by rapidly progressive respiratory compromise is the key complex of signs and symptoms from which the syndrome derives its name. The microbiologic origins of SARS remain unclear.