Attenuation of acute postoperative pain and opioid requirement with the use of magnesium sulfate in patients undergoing limb amputations.

OBJECTIVE: To compare the effects of magnesium sulphate on the total dose of intravenous morphine consumption postoperatively following limb amputations along with rescue analgesia requirement, pain scores and side effects. METHODS: This prospective, triple-blinded, randomised controlled study was conducted from October 2021 to May 2022 at the Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan, and comprised of patients scheduled for limb amputations. They were randomised into 2 equal groups. The anaesthesia protocol was uniform for all patients. Intervention group A was administered 30mg/kg loading dose and 10mg/kg/hr maintenance dose of magnesium sulphate intravenously, while patients in control group B received the same amount of plain isotonic saline. Morphine consumption, including that used for rescue analgesia and patient-controlled analgesia, was measured for 24 hours postoperatively. Numeric rating scale was used for the evaluation of postoperative pain in both groups at 15min, 1h, 2h, at discharge from the post-anaesthesia care unit and at 12h and 24h in the ward. Data was analysed using SPSS 23. RESULTS: Of the 24 patients enrolled, the study was completed by 20(83.33%). There were 10(50%) patients in group A; 8(40%) males and 2(20%) females with mean age 24.8±14.14 years and mean surgery time 130.5±47.86 minutes. There were 10(50%) patients in group B; 8(40%) males and 2(20%) females with mean age 23.2±7.4 years and mean surgery time 117±23.85 minutes (p>0.05). Total morphine used over 24 hours in group A was 16±3.1 mg compared to 29.6±11.2 mg in group B (p<0.05). The time for first use of patient-controlled analgesia after arriving in the postanaesthesia care unit was significantly delayed in group A (72.2±24.95 minutes) compared to that in group B (25±26.68 minutes) (p<0.05). Pain scores were significantly higher in the group B at 15min compared to group A (p<0.05), but not at the rest of the time points (p>0.05). CONCLUSIONS: Intravenous magnesium sulphate proved to be effective in lowering postoperative opioid requirement following limb amputations.

Role of Cardiopulmonary Exercise Testing in Predicting Perioperative Outcomes in Cancer Patients Undergoing Thoracoabdominal Surgeries; An Observational Cohort Study.

Introduction: The cancer patients are at a high risk of developing perioperative complications. Cardiopulmonary exercise testing (CPET) is a non-invasive, perioperative risk stratification tool that predicts perioperative morbidity and mortality. Prior literature has concluded that CPET has a valuable role in predicting post-operative complications in major surgical procedures. However, the data on the effectiveness of CPET in evaluating the perioperative risk in cancer-specific populations are limited. This study assessed the usefulness of CPET in perioperative risk stratification of patients with thoracoabdominal cancer who underwent elective major thoracoabdominal surgeries. Materials and Methods: A retrospective observational cohort study was conducted on cancer patients that underwent pre-operative CPET at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan, from September 2017 to September 2019. All adult male and female patients with a significant medical history for cancer of the thoracoabdominal region who underwent CPET before a major thoracoabdominal surgery were included in the study. Results: A total of 32 patients were included in the present investigation. The mean age of the sample was 62.75 ± 10.18 years, and the majority of the participants were female. Following surgery, 53% of the participants had post-operative complications in terms of morbidity and mortality. Fifteen participants had an anaerobic threshold (AT) of ≥11.0 ml/ kg/min. Among these, 12 participants had an uneventful surgery. On the contrary, among 17 participants that were considered to have a high risk (<11.0 ml/kg/min) for surgery, 14 subjects (82%) had at least one complication (including mortality). The sensitivity and specificity of CPET to anticipate complications during oncological surgery were calculated to be 82% and 80%, respectively. The mean AT of participants with uneventful surgery was calculated to be 11.83 ± 1.01 ml/kg/min. This was statistically greater than the AT of subjects that had morbidity (9.86 ± 1.20 ml/kg/min) or mortality (8.95 ± 0.35 ml/kg/min) (P < 0.001). Conclusion: CPET, when using AT alone as an indicator, can provide a good-excellent prediction of perioperative outcome among oncology patients undergoing major thoracoabdominal surgical procedures.