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Noninvasive positive-pressure ventilation vs. conventional oxygen supplementation in hypoxemic patients undergoing
Massimo Antonelli1, Giorgio Conti, Monica Rocco
1Istituto di Anestesiologia e Rianimazione, Università Cattolica del Sacro Cuore, Rome, Italy. max.antonelli@flashnet.it
Objective:
We have reported previously on the use of noninvasive positive-pressure ventilation (NPPV) to assist spontaneous breathing in high-risk hypoxemic patients (i.e., PaO(2)/fraction of inspired oxygen [FIO(2)] ratio, < or = 100) who are undergoing diagnostic fiberoptic bronchoscopy (FOB). The efficacy of this intervention in patients with less severe forms of hypoxemia (i.e., PaO(2)/FIO(2) ratio, < 200) is unknown.
Patients And Methods:
Twenty-six patients with PaO(2)/FIO(2) ratios < or = 200 who required bronchoscopic BAL for suspected nosocomial pneumonia were entered into the study. Thirteen patients were randomized during FOB to receive NPPV, and 13 patients were randomized to receive conventional oxygen supplementation by Venturi mask. The primary end points were changes in the PaO(2)/FIO(2) ratio during FOB and within 60 min of terminating the procedure. RESULTS AND OUTCOME: At study entry, the two groups were similar in terms of age, simplified acute physiologic score II values, and cardiorespiratory parameters. During FOB, the mean (+/- SD) PaO(2)/FIO(2) ratio increased by 82% in the NPPV group (261 +/- 100 vs 139 +/- 38; p < 0.001) and decreased by 10% in the conventional oxygen supplementation group (155 +/- 24 to 139 +/- 38; p = 0.23). Sixty minutes after undergoing FOB, the NPPV group had a higher mean PaO(2)/FIO(2) ratio (176 +/- 62 vs 140 +/- 38; p = 0.09), a lower mean heart rate (91 +/- 18 vs. 108 +/- 15 beats/min; p = 0.02), and no reduction in mean arterial pressure in comparison to a 15% decrease from the baseline in the control group. One patient in the NPPV group and two patients in the control group required nonemergent intubation. Major bacterial isolates included Staphylococcus aureus (7 of 30 isolates; 23%) and Pseudomonas aeruginosa (12 of 30 isolates; 40%).
Conclusion:
In patients with severe hypoxemia, NPPV is superior to conventional oxygen supplementation in preventing gas-exchange deterioration during FOB with better hemodynamic tolerance.