Factors Affecting the Frequency of Hypotension in Patients Undergoing General Anesthesia
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Abstract
Background: General anesthesia induction-related hypotension is a clinically relevant perioperative event that may occur after anesthetic induction because of vasodilation, reduced systemic vascular resistance, myocardial depression, and impaired compensatory cardiovascular responses. Identification of routinely measurable factors associated with peri-induction blood pressure changes may support safer anesthetic monitoring and early intervention. Objective: To determine pre- and post-induction blood pressure patterns and assess their association with age, sex, body mass index, diabetes status, and propofol dosage among patients undergoing general anesthesia. Methods: This prospective observational study included 182 patients undergoing general surgical procedures under general anesthesia at Surgical Unit 03, Services Hospital, Lahore, from December 2025 to March 2026. Data were collected using a structured proforma and included demographic characteristics, BMI category, diabetes status, propofol dosage, and pre- and post-induction systolic and diastolic blood pressure scores. Data were analyzed using SPSS version 21.0, with bivariate testing applied to assess associations between predictor variables and blood pressure outcomes. Results: The mean age was 37.49 ± 15.16 years, and 97 participants were male. The mean coded systolic blood pressure score decreased from 4.98 ± 1.37 before induction to 2.88 ± 1.29 after induction. Age was significantly associated with pre-induction systolic blood pressure (p = 0.015) and post-induction systolic blood pressure (p = 0.044). BMI category was associated with pre-induction systolic blood pressure (p = 0.006), while sex was associated with pre-induction systolic and diastolic blood pressure (p = 0.045 and p = 0.047). Diabetes status and propofol dosage were not significantly associated with any blood pressure outcome. Conclusion: Age was the most consistent factor associated with peri-induction systolic blood pressure, while BMI and sex were associated mainly with baseline blood pressure status. Future studies should report raw blood pressure values, standardized hypotension thresholds, and adjusted effect estimates
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1. Ida M, Kimoto K, Iwata M, Nakayama K, Kamiya T, Kuzumoto N, et al. Retrospective evaluation of predictors and frequency of hypotension in hypertensive patients after induction of general anesthesia. Masui. 2014;63:614-8.
2. Robinson BJ, Ebert TJ, O’Brien TJ, Colinco MD, Muzi M. Mechanisms whereby propofol mediates peripheral vasodilation in humans: sympathoinhibition or direct vascular relaxation? Anesthesiology. 1997;86(1):64-72.
3. Poterman M, Scheeren TWL, van der Velde MI, Buisman PL, Allaert S, Struys MMRF, et al. Prophylactic atropine administration attenuates the negative haemodynamic effects of induction of anesthesia with propofol and high-dose remifentanil. Eur J Anaesthesiol. 2017;34(10):695-701.
4. Van Waes JAR, Van Klei WA, Wijeysundera DN, Van Wolfswinkel L, Lindsay TF, Beattie WS. Association between intraoperative hypotension and myocardial injury after vascular surgery. Anesthesiology. 2016;124(1):35-44.
5. Charlson ME, MacKenzie CR, Gold JP, Ales KL, Topkins M, Shires GT. Postoperative characteristics predicting intraoperative hypotension and hypertension among hypertensives and diabetics undergoing non-cardiac surgery. Ann Surg. 1990;212(1):66.
6. Nafiu OO, Kheterpal S, Morris M, Reynolds PI, Malviya S, Tremper KK. Incidence and risk factors for preincision hypotension in a non-cardiac pediatric surgical population. Paediatr Anaesth. 2009;19(3):232-9.
7. Reich DL, Hossain S, Krol M, Baez B, Patel P, Bernstein A, et al. Predictors of hypotension after induction of general anesthesia. Anesth Analg. 2005;101(3):622-8.
8. Statistics How To. Find critical values: z alpha/2, zα/2 [Internet]. 2020 [cited 2020 Jul 2]. Available from: https://www.statisticshowto.com/probability-and-statistics/find-critical-values/z-alpha2-za2/
9. Südfeld S, Brechnitz S, Wagner JY, Reese PC, Pinnschmidt HO, Reuter DA, et al. Post-induction hypotension and early intraoperative hypotension associated with general anaesthesia. Br J Anaesth. 2017;119(1):57-64.
10. Jor O, Maca J, Koutna J, Gemrotova M, Vymazal T, Litschmannova M, et al. Hypotension after induction of general anesthesia: occurrence, risk factors and therapy. A prospective multicentre observational study. J Anesth. 2018;32(5):673-80.
11. Okamura K, Nomura T, Mizuno Y, Miyashita T, Goto T. Pre-anesthetic ultrasonographic assessment of the internal jugular vein for prediction of hypotension during the induction of general anesthesia. J Anesth. 2019;33:612-9.
12. Hojo T, Kimura Y, Shibuya M, Fujisawa T. Predictors of hypotension during anesthesia induction in patients with hypertension on medications: a retrospective observational study. BMC Anesthesiol. 2022;22(1):343.
13. Zhou Y, Ke SJ, Qiu XP, Liu LB. Prevalence, risk factors, and prognosis of orthostatic hypotension in diabetic patients: a systematic review and meta-analysis. Medicine (Baltimore). 2017;96(36):e8004.
14. Kalezic N, Stojanovic M, Ladjevic N, Markovic D, Paunovic I, Palibrk I, Milicic B, et al. Risk factors for intraoperative hypotension during thyroid surgery. Med Sci Monit. 2013;19:236-41.