Outcomes Of Aged Patients With High Respiratory Complication Risks After Abdominal Surgery Treated With 12h Positive Pressure Mechanical Ventilation

Objective: To evaluate the effectiveness of 12h positive pressure mechanical ventilation compared with standard treatment in aged patients with risks of pulmonary complication following abdominal surgery whether improved outcomes of the patients in morbidity and mortality during recovery from surgery.Method: The design was a randomized, controlled clinic study between April 2006 and September 2006 at a 16-bed surgery intensive care unit (SICU) of a university hospital. Consecutive patients who matched the study criteria after major abdominal surgery were administered. Of 47 patients were randomly assigned to positive pressure mechanical ventilation group (V group, n=24) or standard treatment group (C group, n=23) with randomized number by computer. In V group, After abdominal surgery, positive pressure mechanical ventilation was immediate administered with a ventilator (NELLCOR PURITAN BENNETT 840; USA) for 12h. The parameter included: tidal value (6-8 ml/Kg), respiratory rate (12-16/min), we used a positive end-expiratory pressure(PEEP) of 5 to 15 cm H₂O while assured a airway plateau pressure (Pplat) below 40 cm H₂O. In C group, patients were treated with nasal oxygen (3-4 L/min) after wake and extubation. All patients were documented demographic, clinical sign and arterial gas after surgery 30 min, 24 hrs, 48 hrs. Clinical outcomes were traced until patients discharged.Result: On admission to the SICU, there were not statically significant differences between V group and C group in terms of age, gender, weight, vital sign, arterial blood gas and type of surgery, APACHEâ…¡(Acute Physiology and Chronic Health Evaluationâ…¡) score. After 24 h treatment, PaO2, PaO₂/FiO₂ ratio was higher in the V group than in the C group (100±24 mm Hg vs 86±19 mm Hg, 334±80 mm Hg vs 288±63 mm Hg, respectively, P＜0.05). Compared with C group after 48 h treatment, the V group had a higher PaO2 (88±12 mm Hg vs 79±14 mm Hg) and PaO₂/FiO₂, ratio (295±40 mm Hg vs 258±45 mm Hg). After 48 h, the C group had more hypoxemia(11[47.8%] vs 3[12.5%], P＜0.05) than the V group. Among outcome variables, the V group had a significantly lower pneumonia complication (1[4%] vs 6[26%], P＜0.05) than the C group, but it fail to improve surgery related complications, length of SICU stay and mortality.Conclusion: Short-term positive pressure mechanical ventilation treatment may improve oxygenation and decrease the related complications in patients with risks of pulmonary complications after major abdominal surgery. This technique may be an alternative to standard treatment in high respiratory risks patients following abdominal surgery.