Effect of the abbreviation of preoperative fasting to 2h with a drink containing carbohydrate in postoperative pulmonary function after Thoracoscopic Sympathectomy: a pilot randomized study

Objective: The organic response to trauma is attenuated by intake of a carbohydrate (CHO)-enriched drink 2 hours before surgery, as opposed to strict preoperative fasting. We investigated whether this approach would improve postoperative respiratory function in patients undergoing bilateral thoracoscopic sympathectomy. Method: Qualifying patients (mean age, 24 years; range, 16-37 year) scheduled for thoracoscopic sympathectomy were randomized to conventional 6- to 8-hour fasting (control group, n=7) or 6-hour fasting for solids, followed by intake of a CHO-rich drink (12% maltodextrin in 200 mL of water) 2 hours before anesthesia (CHO group, n=7). Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and forced expiratory flow between 25% and 75% of FVC (FEF 25-75%) were measured, and cirtometry was performed pre- and postoperatively (Day 1). The visual analog scale (VAS) was used to assess pain and well-being postoperatively. Results: Pain and well-being did not differ between groups by VAS scores. Thoracic expansibility declined postoperatively in both groups at axillary level but significantly decreased at xiphoid level only in the control group (p=0.04). Both groups showed significant declines in FVC and FEV1 on postoperative Day 1. Only the control group displayed significant postoperative FEF 25-75% decline, compared with preoperative baseline (p=0.01). Conclusion: In this pilot study, intake of a CHO-enriched drink 2 hours preoperatively benefitted patients postoperatively, enhancing basilar lung expansion and marginally improving lung function.