Desflurane Versus Total Intravenous Anesthesia With Propofol For Peroral Endoscopic Myotomy In Patients With Low Body Mass Index

ObjectiveEsophageal Echalasia(EA) is an esophageal motility disorder featured with dysphagia, regurgitation, chest pain and weight loss. Dysphagia exacerbates progressively expressed by vomiting or spitting up. Peroral endoscopic myotomy (POEM) was first introduced by Inoue et al. for esophageal achalasia. In this respect, both propofol and desflurane are suitable agents for maintenance of anesthesia during endoscopic surgery because of their favorable pharmacological properties. To our knowledge, there are no published reports comparing desflurane with propofol anesthesia in patients with low body mass index. The purpose of this study is to compare emergence time as measured by time to eye opening and to observe other recovery characteristics of desflurane and total intravenous anesthesia with propofol in sickly and emaciated patients undergoing POEM.Materials and MethodsPatients having body mass index (BMI) values equal to or less than 18.5 were obtained. Sixty patients with low BMI, aged 18 to 65 years, classified as American Society of Anesthesiology physical status II, undergoing POEM in our hospital were enrolled in the prospective, randomized study. All patients were randomly assigned (using a computer-derived randomization list) to receive either propofol(PROP group) or desflurane(DES group) for the maintainance of anesthesia. Patients receiving any sedative or analgesic drugs in 24 hours before surgery, with a history of coronary artery disease, myocardial infarction, congestive heart failure, notable lung disease, and drug abuse were excluded.1. After the application of standard monitors and Bispectral index (BIS) monitor, all patients are preoxygenated with 100% oxygen by facemask for three minutes before induction.2. Propofol and remifentanil are administered with a target controlled infusion device (Orchestra Base Primea, Fresenius Kabi, Germany). General anesthesia is induced with 3 ng·mL-1 and 3μg·mL-1 effect site concentrations (Ce) of remifentanil and propofol, respectively. Sellick’s maneuver is used without manual ventilation before tracheal intubation, and succinylcholine 1.5 mg·kg-1 is infused to facilitate tracheal intubation.3. Maintenance of general anesthesia consists of either desflurane with 50% oxygen in air mixture (propofol infusion stopped) in the desflurane group or propofol target controlled infusion in the propofol group in order to keep BIS value at 50±10. Analgesia is maintained with remifentanil concentration at a Ce of 2 ng·mL-1 and fentanyl titrated in divided doses and limited to a total of 5 ug·kg-1 for the entire procedure. In addition, tropisetron 6 mg is given to all patients for prophylaxis of postoperative nausea and vomiting. Respiratory frequency and tidal volume were adjusted to maintain end-tidal CO2 between 35-45mm Hg.4. Upon the placement of the last endoscopic clip, the anesthetic provider turns desflurane off or stops propofol infusion.The fresh gas flow rate is increased to 8 L·min-1 on 50% oxygen and patients are extubated only after fulfilling the criteria for extubation. Criteria for tracheal extubation include the ability to sustain spontaneous ventilation, a tidal volume greater than 5 mL·kg-1, and response to verbal command.5. Then again on arrival to the PACU, and at 15-minute intervals thereafter until discharge from the PACU or until a return to baseline. Other variables measured on PACU admission and at 15-minute intervals until PACU discharge include SpO2,MAP, heart rate(HR), pain and nausea Visual Analog Scale (VAS) scores. Patients achieving a modified Aldrete score of 8 or more are considered ready for PACU discharge.Results1. All patients enrolled completed the study. Demographic data, including age, sex, and BMI were similar in the PROP group or DES group and no significant difference was found between the 2 groups in surgery time and anesthesia time.2. Patients in the 2 groups received opioid analgesics throughout the procedure in equal amounts:fentanyl infused 183.50±37.258ug in PROP group and 168.37±36.832 in DES group; Remifentanyl infused 330.07±100.334 ug in PROP group and 301.07±107.425 in DES group. There were no significant differences between the 2 groups.3. In PACU, complications were recorded, like vomiting and shivering. There were six patients (female) showing the presence of shivering in PROP group while five patients (female) in DES group (P>0.05). No significant differences were detected in vomiting.4. Emergence was significantly faster for patients receiving desflurane than for patients receiving propofol in our study, The eye opening time in PROP group and DES group is 9.07±4.11min、6.51±2.09min (P<0.05)respectively, the extubation time is 10.16±4.08min、7.55±2.13min (P<0.05)respectively.5. At the end of surgery, while postoperative cognitive scores-MMSE diminished significantly from baseline in both groups, the scores in PROP group declined significantly (24.97±3.76 vs.26.97±3.07;P<0.05), and the lower scores lasted longer until 30min in PROP group, while in the DES group, cognitive impairment returned to normal at 15 minutes after patients reached in PACU(29.33±1.37 vs.28.70±1.92;P>0.05).6. Postoperative pain was low in all groups and VAS at 15 and 30min postoperatively did not vary with anesthetic technique. The consumption of opium in two groups had no difference, while in DES group the patients showed lower VAS scores than in PROP group at the emergency. After 15min in PACU, both groups experienced more serious soreness than at the moment of arriving PACU. Conclusion 1. Our study showed a statistical and clinical difference between the recovery profiles of patients who received desflurane versus propofol. 2. Desflurane associated with a more rapid initial awakening, lessdepression of cognitive function and less impairment of psychomotorperformance could be the more appropriate option for POEM in patients with low BMI.