Use of Intravenous Lidocaine, Magnesium and Ketamine and Acute Pain After Lung Resection Surgery: A Prospective Observational Cohort Study

Background: Thoracic surgery is associated with severe post-operative pain caused by chest wall manipulation and intercostal nerve injury. Multimodal analgesia with non-opioid agents such as lidocaine, ketamine and magnesium might be beneficial for pain control and reduce opioid consumption. Methods: In this prospective cohort study, we recruited 118 consecutive patients who underwent lung resection via thoracotomy from January 2019 to January 2021 at Hospital Universitari de Girona Doctor Josep Trueta. The primary outcome was total intravenous morphine consumption within the first 24 h post-operatively. Multi-variable linear regression modelling was used to determine the adjusted association between lidocaine, ketamine and magnesium administration and morphine consumption in the first 24 h after surgery. Statistical analysis was performed using Wilcoxon’s rank-sum and Fisher’s exact tests. Results: In total, 71 patients received lidocaine, ketamine and magnesium intraoperatively (LKM) and 47 patients did not receive this regimen (non-LKM group). The LKM group had a higher prevalence of hypertension and higher proportions of patients undergoing lobectomy and pneumonectomy. Morphine consumption within 24 h post-operatively was lower in the LKM group than in the non-LKM group (median [interquartile range], 2 [2–6] mg vs. 5 [3–8] mg; p = 0.001). No drug-related adverse events were observed. After multi-variable risk adjustment, lidocaine, ketamine and magnesium use was associated with significantly decreased total intravenous morphine consumption within 24 h post-operatively (−1.76, 95% confidence interval = −3.40 to −0.12, p = 0.03). Conclusions: Lidocaine, ketamine and magnesium use was associated with lower 24-h morphine consumption in our prospective cohort.