Effects of Propranolol and Exercise Training in Children with Severe Burns

Abstract

Objectives To investigate whether propranolol administration blocks the benefits induced by exercise training in severely burned children. Study design Children aged 7–18 years (n=58) with burns covering ≥30% of the total body surface area (TBSA) were enrolled in this randomized trial during their acute hospital admission. Twenty-seven patients were randomized to receive propranolol, whilst 31 served as untreated controls. Both groups participated in 12 weeks of in-hospital resistance and aerobic exercise training. Muscle strength, lean body mass, and peak aerobic capacity (VO2 peak) were measured before and after exercise training. Paired and unpaired Student T-tests were used for within and between group comparisons, and Chi-squared tests for nominal data. Results Age, length of hospitalization, and TBSA burned were similar between groups. In both groups, muscle strength, lean body mass, and VO2 peak were significantly greater after exercise training than at baseline. The percent change in VO2 peak was significantly greater in the propranolol group than in the control group (P< 0.05). Conclusions Exercise-induced enhancements in muscle mass, strength, and VO2 peak are not impaired by propranolol. Moreover, propranolol improves the aerobic response to exercise in massively burned children.

The Role of Exercise in the Rehabilitation of Patients with Severe Burns

“…In agreement with previous findings, RET significantly increased lean body mass and peak torque, where the magnitude of improvement in these outcomes were similar in patients treated with RET and RET + propranolol. However, with regard to VO 2 peak, the 22% improvement from baseline seen in the RET group, while a significant within-group change, was significantly lower than the improvement (36%) in VO 2 peak observed in the RET + propranolol group (25). While a mechanistic explanation as to why propranolol and exercise have an additive effect on VO 2 peak in burned children is currently lacking, the ability of propranolol to attenuate peripheral protein catabolism and blood flow (12) may contribute to improved muscle mass and quality as well as O 2 extraction from arterial blood.…”

“…These effects can be maintained with long-term propranolol treatment (12 months), improving growth and body composition in burned children (17). We have recently published data concerning the effect of long-term propranolol treatment and RET versus RET alone in children with major burns (25). In agreement with previous findings, RET significantly increased lean body mass and peak torque, where the magnitude of improvement in these outcomes were similar in patients treated with RET and RET + propranolol.…”

“…In general, from reviewing the literature, it appears that a conservative approach has been taken until recently, where RET programs have been initiated approximately one year post burn (10, 13), when patients are completely healed and the worst of the pathophysiological response to burn injury has subsided. In our hospital, patients are typically randomized to receive either SoC or RET to test the efficacy of RET on functional outcomes in burned children (1, 4, 5, 25, 28, 30–32). In these instances, RET has been performed at 6 months post burn when patients return to the hospital for follow-up treatment.…”

“…The pathophysiological stress response accompanying burn injury persists for several years (21), as do losses in functional capacity (25). Thus, given that i) burn injury results in major impairments in physical function and ii) advances in acute clinical care mean that major burns are more survivable then every before, there is a real need for effective rehabilitative strategies that augment functional capacity in burn survivors.…”

Therapeutic Approaches to Combatting Hypermetabolism in Severe Burn Injuries

“…In particular, resistance exercise in combination with propranolol was shown to have an additive effect on the VO 2 peak of pediatric patients with burn injuries [69]. This might be explained by exercise enhancing propranolol's positive effects lean body mass and O 2 extraction [69,70]. Similarly, oxandrolone and exercise have also been shown to have synergistic effects in preventing deficits in the lean body mass of pediatric burn patients [71].…”