Evaluation of Haemodynamic Changes in Patients undergoing Total Knee Arthroplasty under Regional Anaesthesia: A Prospective Observational Study
Authors: Bala Manju , Taxak Susheela , Bajaj Paras , Chhikara Monica , Ahlawat Mangal , Zokarkar Ashwini 
Published: October 2023

Introduction: Total Knee Arthroplasty (TKA) is a routinely used procedure for the management of knee osteoarthritis. Various haemodynamic changes can occur during TKA, especially during cementing and tourniquet deflation, which can have a significant impact on the patient’s clinical condition. This study emphasises the importance of close haemodynamic monitoring for the timely detection of potential complications during this procedure. Aim: To evaluate the haemodynamic changes occurring during spinal anaesthesia, bone cementation, and tourniquet deflation using Transthoracic Echocardiography (TTE) along with routine non invasive haemodynamic monitors in patients undergoing TKA. Materials and Methods: The present study was a prospective, observational single-arm study conducted at a tertiary care centre from February 2019 to March 202.Thirty patients of either sex, belonging to American Society of Anaesthesiologists physical status I (aged between 40-70 years) and scheduled for TKA under regional anaesthesia, were enrolled in the study. Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), SpO2 levels, respiratory rate, and End-Tidal CO2 (EtCO2 ) were recorded at various time intervals, including baseline value, after spinal anaesthesia, before cement implantation, after cement implantation, before tourniquet deflation, after tourniquet deflation, and at the end of the surgery. Blood gas analysis and TTE were recorded preoperatively, five minutes after cementation, and five minutes after tourniquet deflation. Data were collected and analysed using Student’s t-test for continuous variables and Chi-square test or Fisher’s exact test for nominal categorical variables. Statistical analysis was performed using the SPSS statistical package (version SPSS 17.0). Results: The mean age, weight, and height of the patients were 54.46±6.78 years, 66.43±5.31 kg, and 152.5±7.71 cm, respectively. The mean HR increased from 82.27±6.11 beats/ minute to 101.43±5.23 and 104.33+4.70 beats/minute after three and six minutes of cementation (p-value=0.001). The mean SBP increased from 121.67 mmHg to 144.13 mmHg and 138.87 mmHg after three and six minutes of cementation (p-value=0.001). The preoperative mean pH was 7.44, which decreased to 7.39 at five minutes after cement implantation and 7.38 after five minutes of tourniquet deflation (p-value=0.001). The preoperative mean PaCO2 value was 44.83 mmHg, which increased to 62.30 mmHg after five minutes of cement implantation and 55.17 mmHg after five minutes of tourniquet deflation (p-value<0.05). Conclusion: There was a significant increase in HR, blood pressure, and PaCO2 , as well as a decrease in pH after bone cement implantation. However, TTE performed at various time points did not suggest any significant changes during TKA. Hence, this study demonstrates that routine haemodynamic monitoring is sufficient, and no additional monitoring like ECHO is required in ASA 1 patients undergoing TKA.