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Brief Summary
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INTRODUCTION
Post operative pulmonary complications are common and major cause of morbidity and mortality.1 They are defined as complications that present within 30 days after the surgical procedure and includes mechanical ventilation for more than 24 hours, hypoxemia, atelectasis, haemoptysis, empyema and death caused by heart or respiratory failure.2
Pre operative evaluation is a basic process of evaluating the patients’ health and the identification of risk factors for the development of any complications in relation to the patient and to the anaesthesia and the planned surgical procedure. Pre operative assessment for those at risk, pulmonary evaluation methods like Spirometry (Pulmonary Function Test-PFT) and Cardio Pulmonary Exercise Testing (CPET) is being employed. The PFT reports are highly influenced by interpretation and patient performance hence it may not be reliable. Cardiopulmonary exercise testing helps in identifying patients who are at a higher risk of developing complications and mortality. However, its application is restricted due to the limited availability of the test. This has indeed stimulated the search for alternate methods which provide similar information that is also simpler and more cost effective.3 Among the alternatives, the step test, the shuttle walk test and the six-minute walk test have been studied.1,3
Alternatives, the step test, the shuttle walk test, and the six-minute walk test (6MWT) have been studied.1,3 The satisfactory results found in the performance of these tests, some points related to the methods – especially the control of exercise intensity, the variability of the results, and level of evidence – require a standardization and interpretation of the results obtained by patients.3
The 6MWT is simple to perform, practical, and does not require special equipment or facilities. The 6MWT is intended to assess, at submaximal levels, exercise walking for six minutes. The test provides an assessment of all systems involved during exercise, including the cardiopulmonary system and the peripheral muscles. As walking is a routine activity and the intensity is defined by the patient, it is usually well tolerated and can be used easily in the preoperative period.4
The 6MWT follows a standardization proposed by the American Thoracic Society (ATS), which makes it a safer and more reproducible technique, however patients may vary the intensity of exercise, which can lead to different results, even when compared with predicted values, which can be predicted by several reference equations.5-11 Additionally, since the predicted values were established for the general population, there is no information available about the expected performance of patients in the preoperative phase, which may be compromised by the underlying disease.
AIMS AND OBJECTIVES
Ø AIM
· Performance In 6-Minute Walk Test In Prediction Of Post-Operative Pulmonary Complication In Major Abdominal Surgeries
Ø OBJECTIVE:
o To assess 6MWD with occurrence of postoperative pulmonary complications.
o To find association of 6MWD with length of hospital stay
o To find difference in haemodynamic parameters like blood pressure (BP), heart rate (HR) and oxygen saturation (SpO2).
REVIEW OF LITERATURE
§ Santos BFA et al (2016) conducted a study that total 21 patients in the preoperative phase of open thoracotomy were evaluated using the 6MWT, followed by monitoring of the postoperative evolution of each participant who underwent the routine treatment. Participants were then divided into two groups: the group with POST-OPERATIVE PULMONARY COMPLICATION and the group without POST-OPERATIVE PULMONARY COMPLICATION. The results were also compared with the predicted values using reference equations for the 6MWT. Over half (57.14%) of patients developed POST-OPERATIVE PULMONARY COMPLICATION. The 6MWT was associated with the odds for POST-OPERATIVE PULMONARY COMPLICATION (odds ratio=22, p=0.01); the group without POST-OPERATIVE PULMONARY COMPLICATION in the postoperative period walked 422.38 (SD=72.18) meters during the 6MWT, while the group with POST-OPERATIVE PULMONARY COMPLICATION walked an average of 340.89 (SD=100.93) meters (p=0.02). The distance travelled by the group without POST-OPERATIVE PULMONARY COMPLICATION was 80% of the predicted value, whereas the group with POST-OPERATIVE PULMONARY COMPLICATION averaged less than 70% (p=0.03), with more appropriate predicted values for the reference equations. The 6MWT is an easy, safe, and feasible test for routine preoperative evaluation in pulmonary surgery and may indicate patients with a higher chance of developing POST-OPERATIVE PULMONARY COMPLICATION.
§ Warangkana Keeratichananont et al (2016) conducted a prospective cohort study was conducted in patients scheduled to undergo elective thoracic or nonthoracic surgery and indicated for preoperative pulmonary evaluation in Songklanagarind Hospital, Songkhla, Thailand. Preoperative spirometry, 6MWT were done and 30-day POST-OPERATIVE PULMONARY COMPLICATION were recorded. The multiple regression analysis and receiver operating characteristic (ROC) curves were used to analyze the variables and to compare the performance of 6MWT and spirometry tests. A total of 78 participants were recruited into the study. 6MWT was done completely in all cases without any complications. Among these tests, 14 cases (17.9%) had contraindications to spirometry and two cases were unable to achieve the criteria for acceptable efforts. POST-OPERATIVE PULMONARY COMPLICATION developed in 17 cases (21%) with a high mortality (17.7%). A multiple regression analysis showed elderly, poor general health status, smoking history, low level of the mean value of forced expiratory volume in 1 second (FEV1) % predicted (by spirometry) and shorter 6-minute walk distance (6MWD) were the independent factors associated with POST-OPERATIVE PULMONARY COMPLICATION. Patients developing POST-OPERATIVE PULMONARY COMPLICATION had a significantly lower preoperative 6MWD compared with patients without POST-OPERATIVE PULMONARY COMPLICATION (256.0} 48.0 versus 440.0 Â} 117.1 meters, p < 0.001). 6MWD of ⩽325 meters was a threshold for predicting POST-OPERATIVE PULMONARY COMPLICATION with 77% sensitivity and 100% specificity, and had a good predictive value for POST-OPERATIVE PULMONARY COMPLICATION similar to that for the FEV1 %. Preoperative 6MWT is a very useful alternative test for predicting POST-OPERATIVE PULMONARY COMPLICATION in high-risk patients scheduled to undergo surgery under GA.
§ Sathyaprasad SL et al (2020) conducted a prospective observational study that total 75 patients who underwent elective abdominal or thoracic oncosurgery under general anaesthesia with either age above 60 years or with cardiopulmonary diseases or obstructive sleep apnoea or low serum albumin or smoking. Patients with history of acute coronary syndrome in past 6 months, dyspnoea at rest, severe pain, inability to walk or interpret instructions and haemodynamic instability were excluded. Preoperatively 6MWT was conducted according to the American Thoracic Society guidelines and patients were observed for POST-OPERATIVE PULMONARY COMPLICATION. Patients were divided into two groups: group 1–no POST-OPERATIVE PULMONARY COMPLICATION and group 2–developed POST-OPERATIVE PULMONARY COMPLICATION. Statistical analysis was done using SPSS software (version 11.0.1). Categorical variables were assessed using Chi-square/Fisher’s exact test and continuous variables using student’s t-test/Mann-Whitney U test. Association was tested using logistic regression. Out of the 75 patients, 40 patients had no POST-OPERATIVE PULMONARY COMPLICATION (group 1) and 35 patients had POST-OPERATIVE PULMONARY COMPLICATION (group 2) including a death. The 6MWD of group with POST-OPERATIVE PULMONARY COMPLICATIONs was significantly less (344 ± 61.927 m) compared to the group without POST-OPERATIVE PULMONARY COMPLICATIONs (442.28 ± 83.194 m, P value = 0.001). The cut-off 6MWD obtained was 390 m, which correlated with longer duration of hospital stay and ICU stay (P = 0.001). Six-minute walk test is a reliable predictor of post-operative pulmonary complications with a cut-off 6MWD of 390 m in the studied oncosurgery patients.
§ Janani et al (2021) conducted a prospective observational study conducted in a tertiary care center for a period of 3 months. 66 patients in the age group of 40-60 years undergoing elective abdominal surgery under general anaesthesia were included in this study based on universal sampling method. Patients with recent coronary syndrome, uncontrolled hypertension, cardiac diseases, pregnancy and conditions which impair walking (e.g., Arthiritis) were excluded from the study. 6-minute walk test was performed before the surgery. The procedure was explained to the patients and consent was obtained. The test was conducted on a flat surface of 20m near our pre anaesthetic clinic and the patient was asked to walk for a period of 6 minutes in their own comfortable pace. The distance covered by the patients in the 6 minutes was noted. Vitals such a SpO2, heart rate, systolic and diastolic blood pressures were recorded before and after the test. The patients were followed up for the development of pulmonary complications in the post operative period. Out of the 66 patients included in the study, 35 patients did not develop POST-OPERATIVE PULMONARY COMPLICATION (Group 1) and 31 patients developed POST-OPERATIVE PULMONARY COMPLICATION (Group2) including one death due to respiratory failure. The six-minute walk distance in the POST-OPERATIVE PULMONARY COMPLICATION group was significantly less (p=0.0001) when compared to that of the non-POST-OPERATIVE PULMONARY COMPLICATION group. Patients in the POST-OPERATIVE PULMONARY COMPLICATION group also required prolonged hospital stay. Pneumonia was the most commonly developed post operative pulmonary complication. Six-minute walk test is a useful tool in predicting post operative pulmonary complication in patients undergoing abdominal surgery.
§ Ramos, R. et al (2021) conducted a study that total 545 adults (≥ 40 yrs.) who were at elevated cardiac risk and had elective inpatient non-cardiac surgery at 15 hospitals in Canada, Australia, and New Zealand. Each participant performed a preoperative 6MWT and was followed for 30 days after surgery. The primary outcome was moderate or severe in-hospital complications. The secondary outcome was 30-day death or myocardial injury. Multivariable logistic regression modelling was used to characterize the adjusted association of 6MWT distance with these outcomes. Seven participants (1%) terminated their 6MWT sessions early because of lower limb pain, dyspnoea, or dizziness. Eighty-one (15%) participants experienced moderate or severe complications and 69 (13%) experienced 30-day myocardial injury or death. Decreased 6MWT distance was associated with increased odds of moderate or severe complications (adjusted odds ratio, 1.32 per 100 m decrease; 95% confidence interval, 1.01 to 1.73; P = 0.045). There was no association of 6MWT distance with myocardial injury or 30-day death (non-linear association; P = 0.49). Preoperative 6MWT distance had a modest association with moderate or severe complications after inpatient non-cardiac surgery. Further studies are needed to determine the optimal role of the 6MWT as an objective exercise test for informing preoperative risk stratification.
Prajapati PP, et al (2021) conducted a study that preoperative 6-minute walk test (6MWT) and to determine the association of 6-minute walk distance with postoperative pulmonary complications (POST-OPERATIVE PULMONARY COMPLICATION) in patients undergoing elective abdominal surgery under general anaesthesia. The study was done in 60 adult high-risk patients who were undergoing planned elective abdominal surgery under general anaesthesia. Patients having acute coronary disease, NYHA IV, unable to walk etc. were excluded. Preoperatively 6MWT was conducted according to the American Thoracic Society guidelines and patients were observed for POST-OPERATIVE PULMONARY COMPLICATION until they discharged from the hospital or died. Statistical analysis was done using SPSS software Total 60 patients were recruited into the study. 6MWT was done completely in all cases without any complications. Out of the 60 patients, 32 patients had no POST-OPERATIVE PULMONARY COMPLICATION (group 1) and 28 patients had POST-OPERATIVE PULMONARY COMPLICATION (group 2). The 6MWD of group with POST-OPERATIVE PULMONARY COMPLICATIONs was significantly less (344 _ 61.927 m) compared to the group without POST-OPERATIVE PULMONARY COMPLICATIONs (442.28 _ 83.194 m, P value = 0.001). The cut off 6MWD obtained was 390 m, which correlated with longer duration of hospital stay and ICU stay (P = 0.001). A multiple regression analysis showed elderly, smoker and shorter 6-minute walk distance (6MWD) were the independent factors associated with POST-OPERATIVE PULMONARY COMPLICATION. 6MWT is a reliable predictor of postoperative pulmonary complications with a cutoff 6MWD of 390m in the high-risk elderly patients posted for upper abdominal surgery patients. |