[Effect of transcutaneous electrical acupoint stimulation on pulmonary function and oxidative stress response in...

To investigate the effect of transcutaneous electrical acupoint stimulation (TEAS) on pulmonary function, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content in patients using tourniquet after lower extremity surgery.

A total of 40 patients who underwent lower extremity surgery were equally randomized into control group and TEAS group by using a random number table. All patients underwent lumbar epidural anesthesia combined with block anesthesia. The patients in the TEAS group were given TEAS at Zusanli (ST36) and Sanyinjiao (SP6) beginning from 30 min before surgery to the end of surgery, and those in the control group received TEAS at the same acupoints with minimum current intensity. Mean arterial pressure (MAP) and heart rate (HR) were recorded at each time point (T₀: pre-surgery /TEAS, T₁: 5 min after anesthesia, T₂: 1 min before tourniquet-loosening, T₃: 1 min after tourniquet-loosening, T₄: 5 min after tourniquet-loosening, and T₅: 6 h after tourniquet-loosening). Blood samples (4 mL) was collected from the radial artery before TEAS and 6 h after loosening tourniquet for analyzing blood gas parameters as partial pressure of caron dioxide(PCO₂), arterial partial pressure of oxygen (PaO₂), alveolar partial pressure of oxygen (PAO₂), alveolar-arterial oxygen pressure difference (PA-aDO₂) and respiratory index (RI) by using a blood gas analyzer, and plasma SOD activity and MDA content were assayed by using xanthine oxidase method and thiobarbituric acid colorimetry method, respectively.

Intra-group comparison showed that compared with T₀, a significant increase was found in PA-aDO₂ and RI at T₅ and a significant reduction in PaO₂ and PaO₂/ PAO₂ (a/A) ratio in the control group (P<0.05), and the same changes in the TEAS group (P<0.05) except a/A ratio. Comparison between two groups showed that at T₅, both PaO₂ and a/A levels were significantly higher in the TEAS group than in the control group (P<0.05), and both PA-aDO₂ and RI levels were obviously lower in the TEAS group than in the control group (P<0.05), suggesting an improvement of the pulmonary function after TEAS. At T₅, plasma SOD activity was significantly decreased and plasma MDA content was remarkably increased in the control group relevant to T₀ (P<0.05), SOD activity was significantly higher in the TEAS group than in the control group (P<0.05), and MDA content was evidently lower in the TEAS group than in the control group (P<0.05), suggesting a reduction of oxidative stress response after TEAS.

TEAS at ST36 and SP6 can improve pulmonary function and attenuate oxidative stress response in patients using tourniquet after lower extremity surgery.