Background:Continuous thoracic paravertebral block (TPVB) provides effective analgesia for unilateral multiple fractured ribs (MFR). However, prolonged infusion of local anaesthetic (LA) in high doses can predispose to risk of LA toxicity, which may be reduced by using safer drugs or drug combinations. This study was conducted to assess efficacy and safety of paravertebral infusion of ropivacaine and adrenaline with or without fentanyl to provide analgesia to patients with unilateral MFR.Methods:Thirty adults, having ≥3 unilateral MFR, with no significant trauma outside chest wall, were studied. All received bolus of 0.5% ropivacaine 0.3 ml/kg through paravertebral catheter, followed by either 0.1-0.2 ml/kg/hr infusion of ropivacaine 0.375% with adrenaline 5 μg/ml in group RA or ropivacaine 0.2% with adrenaline 5 μg/ml and fentanyl 2 μg/ml in group RAF. Rescue analgesia was provided by IV morphine.Results:Statistical analysis was performed using unpaired Student t-test, Chi-square test and repeated measures ANOVA. After TPVB, VAS scores, respiratory rate and PEFR improved in both groups with no significant inter-group differences. Duration of ropivacaine infusion, morphine requirements, length of ICU and hospital stay, incidence of pulmonary complications and opioid-related side-effects were similar in both groups. Ropivacaine requirement was higher in group RA than group RAF. No patient showed signs of LA toxicity.Conclusion:Continuous paravertebral infusion of ropivacaine 0.375% with adrenaline 5 μg/ml at 0.1-0.2 ml/kg/hr provided effective and safe analgesia to patients with unilateral MFR. Addition of fentanyl 2 μg/ml allowed reduction of ropivacaine concentration to 0.2% without decreasing efficacy or increasing opioid-related side-effects.