Intravenous versus Ultrasound Guided Thoracic Paravertebral Morphine-Dexmedetomidine Combination in Patients with Multiple Rib Fractures

Background: Severe pain caused by multiple rib fractures (MRF) can compromise oxygenation, ventilation and pulmonary functions so can affect patient outcome. Adequate pain control helps to avoid these complications. Thoracic paravertebral analgesia is comparable to thoracic epidural with fewer side effects. Methods: Seventy-five patients were randomly allocated into three groups, (n=25 each). Group (GM) received intravenous morphine with a loading dose of 0.1-0.2 mg/kg followed by PCA bolus of 1mg with a six min lockout. Group (GMD) received also intravenous morphine with a loading dose of 0.1-0.2 mg/kg then PCA bolus of 1 mg morphine plus 5 μg dexmedetomidine with a six min lockout. Group (GPV) received paravertebral morphine loading dose of 0.2 mg/kg then PCA bolus of 0.1 ml/kg of a solution with a concentration of 0.5 mg/ml morphine mixed with 1 μg/ml dexmedetomidine and 60 min lockout. Any patient with VAS score more than 4, a top-up dose was given until VAS ≤ 4 Results: No significant difference between the three groups as regards age, BMI, sex, and ASA. Road traffic accident was the main cause of blunt chest trauma (64%, 76% and 68% in GM, GMD, and GPV respectively). Total morphine requirements were significantly lower in GMD and GPV than GM and in GPV than GMD (GM=190.9 ± 45.26, GMD=117.1 ± 31.9 and GPV=86.2 ± 21.7). There was a significant decrease in nausea and vomiting in GMD and GPV than GM. No significant difference in RR between the three groups although 8 patients in GM developed respiratory depression which was significantly higher than in GMD (2 patients) and GPV (0 patient). No significant difference in HR, MAP, and SpO2 between the groups. VAS scores at rest and with cough were significantly lower in both GMD and GPV than GM. FVC, FEV1 and PaO2/FiO2 ratio were significantly increased and PaCO2 significantly decrease in GMD and GPV than GM. Conclusion: Adding dexmedetomidine to morphine either TPV or IV PCA significantly decreases VAS scores, improves pulmonary functions and also decrease morphine consumption with fewer side effects in patients with MRF.