RESUMO
Objective:To evaluate the effect of hydrogen on lung injury induced by extremity ischemia-reperfusion (I/R) in elderly patients.Methods:Sixty American Society of Anesthesiologists physical status Ⅱ or Ⅲ elderly patients, aged 65-75 yr, with height 155-180 cm, weighing 50-75 kg, undergoing lower limb surgery under spinal anesthesia, were divided into 2 groups ( n=30 each) using a random number table method: hydrogen inhalation group (H group) and control group (C group). In H group, 67% hydrogen-33% oxygen was inhaled through the nasal catheter until the end of surgery starting from the completion of anesthesia.In group C, 33% oxygen was inhaled through the nasal catheter until the end of surgery after the completion of anesthesia.Blood samples from the radial artery were collected before anesthesia and at 60 min after tourniquet deflation.Blood gas analysis was performed to determine and record arterial oxygen partial pressure (PaO 2) and arterial carbon dioxide partial pressure (PaCO 2), and alveolar-arterial partial pressure of oxygen difference (A-aDO 2), oxygenation index (OI) and respiratory index (RI) were calculated.Pulmonary surfactant protein D (SP-D) and interleukin-6 (IL-6) concentrations in serum were measured by enzyme-linked immuno sorbent assay.ICU stay time and incidence of pulmonary complications within 7 days after operation were recorded. Results:Compared with group C, PaO 2 and OI were significantly increased, RI and A-aDO 2 were decreased, SP-D and IL-6 concentrations in serum were decreased at 60 min after tourniquet deflation, and ICU stay time was shortened ( P<0.05), and no significant change was found in the incidence of pulmonary complications within 7 days after surgery in group H ( P>0.05). Conclusion:Hydrogen can reduce the lung injury induced by extremity I/R, and the mechanism may be related to the reduction of inflammatory response in elderly patients.