[Effect of lung protection mechanical ventilation on respiratory function in the elderly undergoing spinal fusion]

To determine the effect of lung protection mechanical ventilation on respiratory function in the elderly undergoing spinal fusion.

Sixty 70-85 year old patients, ASA class II or III, undergoing spinal fusion were randomly assigned into 2 groups (30 in each group): a protection mechanical ventilation group (group P) and a conventional mechanical ventilation group (group C). Low VT and low level positive end expiratory pressure (PEEP) mechanical ventilation were applied in group P (VT=6mL/kg, RR=12-18 b/min, I:E=1:2, PEEP=10 cmH2O, alveolar recruitment performed once every 15 min), while traditional ventilation was used in group C ( VT=10-12 mL/kg, RR=12 b/min, I:E=1:2). Arterial blood samples were taken and pH, PaO2, PaCO2, PaO2/FiO2, A-aDO2, HR, SBP, DBP and CVP were recorded before the operation (T0), 1 h after tracheal intubation (T1), tracheal extubation immediately (T2), 1 h after tracheal extubation (T3), 1 d, 2 d, and 3 d after the operation (T4, T5, and T6). The pulmonary complication was also examined 1 d after the operation.

At T1, T2, T3, T4 and T5, PaO2 and PaO2/FiO2 in group P were higher than those in group C, but A-aDO2 in group P was lower than that in group C. Five patients had bronchitis, 5 had hyoxemia, and 3 had atelectasis in group C, but 2 bronchitis in group P. The incidence of pulmonary complication was 43.3% in group C and 6.6% in group P. There was no significant difference in HR, SBP, DBP and CVP between the 2 groups.

Lung protection mechanical ventilation improves the arterial oxygenation and accelerates the recovery of respiratory functions in elderly patients after spinal fusion operation, with no influence on hemodynamics.