The effect of cigarette smoking on anaesthetic consumption in minor gynaecological procedures under total intravenous anaesthesia with Propofol
Creators: name: Tonev, Dimitar
Publisher: name: F1000Research
Year: 2015

description: <i>Introduction:</i> <br>Published data suggest that female patients have higher maintance infusion rates of total intravenous anaesthesia (TIVA) with propofol and more rapid decline in plasma propofol levels than male patients. In addition, smokers lost consciousness at higher propofol concentrations than non-smokers. There are no published data on the combined effect of female gender and cigarette smoking on the propofol consumption and this is the aim of our study.<br><br><i>Material and Methods:</i><br>We undertook retrospective analysis of 183 consecutive ASA I-III nonpregnant female patients who underwent hysteroscopy and dilatation and curettage procedure (combined with LEEP/ polypectomy/ biopsy when needed).  Two anaesthetic techniques were indentified: face mask (50% O<sub>2</sub>/air mixture) with opioid TIVA (i.v. boluses of Fentanyl 1 µg/kg and Propofol 2 mg/kg for induction followed by Propofol 10 mg/min as required ) or face mask with opioid-free TIVA (i.v.  Paracetamol 1,0 g before induction followed by same regimes of Propofol administration). No opioid was administered intraoperatively. Data regarding age, height, weight, ASA status, smoking status, type and duration of surgery, type and duration of anaesthesia and Propofol consumption were collected. As described by others, all smokers were compared with their corresponding non-smokers (matched by age, height, weight, ASA physical status,  type and duration of surgery, type and duration of TIVA). We tested all confounding variables (matching criteria) with the dependent variable (Propofol consumption)  and conducted (according to median Propofol consumption) binary logistic regression as well.<br><br><i>Results:</i> <br>Of 183 patients aged  46,4±10,7 years, BMI 25,5±5,4 kg/m<sup>2</sup>, there were 130/183 patients (71%) who had opioid TIVA anaesthesia and 53/183 patients (29%) had opioid-free TIVA. There were no demographic or ASA differences between the two groups. Of 183 cases, 36 patients (19,7%) were smokers. The average Propofol consumption of patients who received opiod TIVA was 200,8±75,6 mg, while that for opioid-free TIVA was 204,5±64,0 mg (p = 0,405). The average Propofol consumption of smokers was 179,5±59,5 mg (range 100 – 400 mg), while that of non-smokers was 150,9±31,3 mg (range 100 – 210 mg)(p = 0,023). The exclusion of patients aged &gt; 50 years or these with ASA III does not affect the established significant difference. Of 72 matching cases, 37 patients (51,4%) had Propofol consumption &lt; 150 mg and the rest 35 patients (48,6%) consumption  &gt; 150 mg (binary clustering).  The logistic regression revealed that the probability of Propofol consumption &gt; 150 mg was 3,6 times higher in women smokers than in those who were non-smokers (OR 3,55, 95% CI, range 1,26- 10,0 ; p = 0,017).<br><br><i>Conclusion: </i><br>Both female gender and cigarette smoking are factors increasing anaesthetic consumption in patients undergoing minor gynecological procedure under TIVA with propofol.