(c ) Length of Hospital stay: Association of preoperative smoking abstinence duration to the intraoperative hemodynamic variability, postoperative pain and length of hospital stay: A prospective cohort study Authors: Mohsin Nazir Butt, Gauhar Afshan Institution: Department of Anaesthesiology, The Aga Khan University Hospital Karachi, Pakistan Results: A total of 89 patients meeting the eligibility criteria were included for analysis. Introduction: In Pakistan prevalence of smoking among males and females varies from 36% to 9%. A smoking prevalence study in Karachi showed a prevalence of about 32.7% (2). Up to 20% of all patients coming for elective surgical procedures are smokers (4). The aim of this study is to determine the association of short term preoperative smoking cessation to the intraoperative hemodynamics, postoperative pain and length of hospital stay. There is paucity of data in the field of anesthesia which can define the guidelines for short term preoperative smoking abstinence . (c ) Length of Hospital stay: Length of Hospital Stay (Days) Beta Coefficients 95% CI DM 0.155 -0.31 – 0.62 Preoperative smoking abstinence -0.001 -0.003 – 0.0005 BMI -0.062 -0.11 - -0.01 Surgery duration -0.003 -0.01 – 0.004 Surgery duration * BMI 0.0003 0.00004 – 0.0007 Constant 1.8209 1.40 – 2.23 Haemodynamic Variables: Distribution of heart rate & Mean blood pressure: Adjusted R squared = 0.158 Length of Hospital Stay= β0 + β1(BMI)+β2(Surgery duration)+ β3(DM)+ β4(Smoking cessation duration) +β5(Surgery duration*BMI) Conclusion: The preoperative smoking abstinence duration was significantly associated with heart rate variability and postoperative pain scores. A significant interaction found between duration of surgery and BMI in estimating the effect of preoperative smoking abstinence duration on the length of hospital stay. Methods: Departmental and institutional ethical approval was taken. It was a prospective cohort design. The study was conducted at the Aga Khan University Hospital Karachi Pakistan. Sampling technique was nonprobability purposive sampling. A minimum sample sizes of 104 patients were required to achieve 90% power using one correlation analysis to detect a correlation difference of -0.2. Adult smokers of 18 to 65 years of age either sex, coming to the operating rooms for elective non-cardiac surgeries, selected in this study. STATA software was used to analyze data. Generalized estimating equation (GEE) was used to estimate the intraoperative heart rate, mean blood pressure variability and postoperative pain. Length of hospital stay was analyzed by multiple linear regression. (a) Intraoperative haemodynamic: Outcomes Unadjusted Beta Coefficients (95% CI) Adjusted Beta Coefficients Mean Arterial Pressure -0.00004 (-0.010 – 0.010) 0.0015 (-0.0079 – 0.012) (a)   Heart rate - 0.045 (-0.073 – -0.017) -0.043 (-0.073 – -0.014) (b) References: Maher R, Devji S. Prevalence of smoking among Karachi population. Prevalence. 2002. Wong J, Lam DP, Abrishami A, Chan MT, Chung F. Short-term preoperative smoking cessation and postoperative complications: a systematic review and meta-analysis. Canadian Journal of Anesthesia/Journal canadien d'anesthésie. 2012;59(3):268-79 (a) Adjusted for age, smoking intensity, education and BMI (b) Adjusted for hypertension, alcoholic, ethnicity, and education (b) Postoperative Pain: Outcome Unadjusted Beta Coefficients (95% CI) Adjusted Beta Coefficients Postoperative Pain -0.011 (-0.013 – -0.0094) -0.011 (-0.013 – -0.0088) (*)   (*) Adjusting for analgesic technique, postsurgical complications, length of stay, ASA and asthma/COPD