Effects of General Anesthesia on Noninvasively Measured Central and Peripheral Blood Pressure: A Prospective, Observational-based Cross-over Study

Abstract

Abstract Background: Blood pressure (BP) monitoring is the basic hemodynamic parameter necessary to monitor the hemodynamic changes occurring under general anesthesia (GA) to maintain adequate perfusion to major organs such as the heart, brain, and kidneys. Physicians heavily rely upon peripheral hemodynamic measurements despite availability of devices suitable for measurement of central blood pressure through non-invasive manner paving a gap in the literature concerning the effects of GA on central pressure. Aims and Objective: In this comparative cross-over study, authors have aimed to find out the degree of changes in central and peripheral BP after the introduction of GA among adult patients of different age groups scheduled for routine surgical procedures with an objective to maintain vital functions more precisely – considering the fact that vital organ perfusions (heart, brain etc.,) depend more on the required values of CBP than that of PBP. Material & Methods: Following approval from IEC, sixty adult patients with ASA physical status 1 or 2 undergoing routine surgical procedures under general anesthesia were enrolled in this prospective cross-over study where each patient was case as well control for measurement and comparison of his/her central and peripheral blood pressure. Patients, being divided into three groups as per age range - 20-40 years (Group A), 40-60 years (Group B), and 60-80 years (Group C) had their normal Riva Rocci BP cuff (Space Lab Inc. USA) placed in one arm for peripheral BP measurement and special Riva Rocci (Uscom Ltd., Australia).) BP cuff for on another arm for Central BP measurement. After patient’s arrival into operation theatre, baseline hemodynamic parameters were taken followed by sequential measurements of CBP and PBP with an interval of 2 minutes till 30-40 mins of operation. There were alternative measurements of these pressures with recording of data from either of the devices as mentioned for further comparison and analysis. Results: From baseline values, it was found that all the three groups were comparable in respect of age, height, weight, PBP and CBP. When measured pressure of all groups combined, that there was a fall in both Central and Peripheral SBP as well as DBP after giving intravenous induction agent (propofol) and rise in both central and peripheral SBP and DBP after laryngoscopy and intubation. Degree of systolic blood pressure change in both peripheral & central that is fall of BP in 3rd reading & rise of BP in 5th reading was greatest in group C, followed by group B, then group A [p - 0.005]. While comparing three subgroups, the baseline Augmentation Index (AI) was highest in group C and lowest in group A. Following the administration of general anesthesia (GA), the change in Augmentation Index (ΔAI), was most pronounced in the third reading corresponding to the time after the administration of the induction agent. Conclusion: Measurement of CBP through peripheral placement of cuff is a unique feasible method to detect real changes of circulation with actual pressure in vital organs. Thus, the study suggests that central blood pressure measurements can provide a more accurate reflection of hemodynamic changes during general anesthesia, especially in older individuals or those with different cardiovascular conditions allowing better vital management of body circulation.