Anaesthesia for Laparoscopic Sleeve Gastrectomy

After obtaining the ethics committee approval of El Menoufia University hospital and the informed written consent from the patients, a hundred morbidly obese patients scheduled for sleeve gastrectomy were recruited for the study. Patients with history of cardiac comorbidity, chronic obstructive lung disease, drug abuse, expected difficult intubation patients, and patients with history of allergy to the study drugs were excluded from the study. Patients from 30 to 50 years old of both sexes were randomly allocated using computerized software into two groups, fifty patients in each group. Patients in inhalation group received intra-operative inhalational anaesthetic while patients in TIVA group received TIVA for anaesthetic maintenance.

All patients received a routine premedication with oral sodium citrate 15ml [0.3 molar (1.16gm)] and intravenous (IV) 4mg ondansetron fifteen minutes before induction. Patients in both groups were connected to the routine monitoring and bispectral index (BIS) upon arrival to theatre. Anaesthesia induction for both groups was carried out by 0.5-1 mcg kg -1 remifentanil, 2-3mg kg-1 propofol, and 0.6 mg kg-1 rocuronium. Endotracheal intubation was done with the appropriate tube size.

In the inhalational group, anaesthesia was maintained by desflurane in low flow oxygen air mixture 60/40%. In the TIVA group, anaesthesia was maintained using propofol 8-12 mg kg-1 h-1 and dexmedetomidine 0.5-1ugkg-1h-1. Remifentanil infusion of 0.05-2 µg kg-¹min-¹ was administered for both groups. Muscle relaxation was maintained in both groups by rocuronium infusion at a rate of 10-12ug kg1min-1. Depth of anaesthesia was monitored by bispectral index and anaesthetics were adjusted in both groups to obtain BIS of 40 to 60 by giving boluses of 0.5ug kg-1 remifentanil. The total boluses of intra-operative remifentanil were recorded. At the end of the procedure all patients received 0.6mg atropine and sugammadex 16mg kg-1 to reverse the effect of rocuronium. Patients were extubated and transferred to the post-anaesthetic care unit (PACU).

Post-operative pain was monitored using visual analogue score (VAS) at PACU. Morphine sulphate 2 to 3 mg was given if the VAS was > 4. Intravenous paracetamol 1gm and/or ketorolac 30 mg were given eight hourly intravenously if needed (VAS ≥3). Post-operative ondansetron 4mg every eight hours was given if required.

Haemodynamics including heart rate and mean arterial blood pressure (MABP) were recorded as a baseline and every fifteen minutes intra-operatively. Recovery time from anaesthesia using Aldrete score was recorded (the time from cessation of all anesthetics until complete recovery). 10 The incidence of post-operative nausea and vomiting, post-operative analgesic requirements, and the duration of PACU stay were recorded. Post-operative pain assessment using VAS from 0 to 10, where 0 means no pain and 10 is the worst pain the patient experienced. VAS was recorded at full recovery, every 15 minutes in PACU until discharge PACU. Time of onset of post-operative bowel movement was recorded.

Statistical analysis:

Sample size calculation was calculated using Graphed Instant statistics version 3. Based on the previous, studies propofol was expected to produce a drop in the MABP after induction of anaesthesia by about 10 mmHg with a standard deviation of 15 mmHg so by choosing level of significance 0.05 and power of 90%; the calculated sample size was 48 patients so that the number of patients randomized in each group was fifty patients to ensure reliable results.

Statistical analysis was done using SPSS 19 (SPSS Inc, IBM company, Chicago,USA). The patients' sex, American society of anaesthetists (ASA) status and incidence of side effects were analyzed using the chi-square χ2-test. Other parameters were compared using student t-test. For comparisons within the same group, paired t-test was used where for comparisons between groups; unpaired t-test was used. P-value less than 0.05 was considered statistically significant.