Objective: To describe the blood gas features and short-term outcomes of noninvasive positive pressure ventilation (NPPV) treatment for acute respiratory failure (ARF) in patients with severe acute respiratory syndrome (SARS) in this retrospective case series study sought.
Methods: Between April 22 and May 1, 2003, 120 clinically compatible SARS patients were admitted to a special hospital for infectious diseases in Beijing. All patients' records were reviewed. The outcome variables of NPPV therapy were analyzed.
Results: At 6 weeks of SARS onset, 25% (30/120) patients had respiratory failure with ALI/ARDS. 16 (53%) had hypercapnia (PaCO(2) > 45 mm Hg) during the course of SARS. 28 of them received NPPV therapy. One was intolerable to NPPV treatment. In the remaining 27 patients, NPPV was initiated 1.2 +/- 1.6 (0 - 10) days after onset of respiratory failure. One hour of NPPV therapy led to significant increases in PaO(2), SpO(2) and PaO(2)/FiO(2), and decrease in respiratory rate (all P < 0.01). 18 of the 27 patients were weaned successfully from NPPV. The mean duration of NPPV use was 10 +/- 6 (5 - 30) days. In addition to one patient who was intolerable to NPPV treatment, intubation was required in other 9 patients who initially had a favorable response to NPPV. Remarkable pulmonary barotrauma was noted in 7 of the 120 (5.8%) patients with SARS, among which 1 developed 2 days after intubation, and 6 occurred while the patients were on NPPV, the incidence being 22% (6/27) in patients using NPPV. The fatality rate at 13 weeks of SARS onset was 6.7% (8/120) in the patient cohort, and 26.7% (8/30) in the ALI/ARDS patients. No SARS occurred in medical staff taking care of NPPV patients.
Conclusions: Some of the SARS patients with ALI/ARDS could experience CO(2) retention, which might be related to the impairment of respiratory muscles. It is proved to be feasible and appropriate for NPPV treatment of respiratory failure in SARS patients who were at high risk of intubation related complications. As there was a high incidence of remarkable barotrauma, a careful lung protective strategy is necessary during the administration of NPPV as well as invasive mechanical ventilation.