雙向氣道正壓通氣應用於神經外科術後病人之成效－前導型試驗

Purpose: Postoperative neurosurgical patients had the high risks of developing pneumonia or lung injury due to the use of anesthetic agents. High tidal volume may further injury the lung. The purpose of this study is to examine the protective lung strategy via biphasic positive airway pressure (BIPAP) through the observation of (1) breathing pattern; (2) arterial blood gas; (3) hemodynamic; (4) intracranial pressure; (5) cerebral perfusion pressure in postoperative neurosurgical patients. Methods: This study was a prospective, randomized, controlled trial. Postoperative neurosurgical patients were randomized into control group ( setting value: volume assist/control mode, VT 10ml/kg/IBW, Ti l second ) and BIPAP group (setting value：BIPAP mode, Phigh: VT8ml/kg/IBW, Thigh 1 second and T low 4 seconds, and Phigh 80% to 100% setting value in pressure support), settings adjusted according to patient's clinical condition. All patients' respiratory rate were adjusted to maintain PaO2≧90mmHg or SaO2 or SpO2≧98%. Breathing pattern, hemodynamic and cerebral perfusion pressure were measured every 4 hours until patients were weaned from ventilator. Results: Total 26 patients were included in this study. 14 patients were in control group with 9 males (53.8%). 12 patients were in BIPAP group with 6 males (46.2%). There was no significant differences in age between control group (average 62.2 years) and BIPAP group (average 59.2 years). The tidal volume and minute volume were obviously lower in BIPAP group than in control group, (p＜0.05). No obvious differences between the two groups in peak airway pressure, plateau pressure and positive end-expiratory pressure. Oxygen concentration and positive end expiratory pressure used was obviously lower in BIPAP group than in control group. Though PaO2 and PaCO2 were higher in BIPAP group, there was no significant difference between the two groups. Blood pressure (systolic pressure, diastolic pressure and mean blood pressure), intracranial pressure, and cerebral perfusion pressure also showed no difference between two groups (p＞0.05). Days of ventilator use was shorter in BIPAP group than in control group (p=0.03). The number of pneumonia and tracheostomy developed were lower in the BIPAP group but no difference was observed between the two groups. The mortality rate in ICU was obviously lower in BIPAP group than in control group (p=0.04). Conclusion: When intracranial pressure were controlled and cerebral perfusion pressure were maintained at stable level, the application of low tidal volume protective lung strategy via biphasic positive airway pressure ventilation could effectively lower the setting of oxygen concentration, improve oxygenation and lower the days of using ventilator.