Discussion
Diaphragm mobility, Pulmonary complications, nerve block, diaphragmatic palsy
PULMONARY COMPLICATIONS
Brachial plexus block, a kind of local anesthetic, is effective in shoulder and upper limb surgery with or without general anesthesia [The brachial plexus is close to the abdominal branch of the C5 nerve at the cricoid cartilage, with an average distance of 1.8 mm. On average, the distance between the brachial plexus and phrenic nerve increases by 3 mm for every 1 cm of the neck to the caudal end. Thus, it is easy to infer that the phrenic nerve is highly vulnerable to also be blocked during an ISB. Diaphragm mobility is first affected, then the blockage involves the lung function. Our preliminary study showed that the diaphragm mobility of group I was lower than that of group S at TThe main observation indicators of our experiment indicated that the incidence of the phrenic nerve block of group I was 67%, and the rate of diaphragmatic palsy of group S was 41%. Incidence of HDP after ISB from our study was lower than previous studies [Decreased diaphragm activity affects the patient’s breathing. The invasive operation of blood gas analysis of patients during a short operation time is not in line with the principle of benefiting them. Therefore, we evaluated the patient’s respiratory function by non-invasive lung function measurements. General anesthesia was applied to these patients after the nerve block, which might increase patient comfort. Since the pulse oximetry were affected by general anesthesia, we do not include it in the detection index. Other studies have shown that as long as the patients were in good physical condition, unilateral phrenic nerve block was less likely to cause a severe drop in pulse oximetry [Pulmonary complications mostly occur in the postoperative period. Our results showed that pulmonary function testing (FVC and FEVThe differences in analgesic effect just failed to reach statistical significance at TOur study has several limitations. Considering compliance to the treatment of the patients, our measurements pertained only to the 12 h postoperative period, and thus the recovery time of respiratory function in group I needs to be explored in larger, longer-term studies. Besides, local anesthetic volume and needle type were also not taken into account.