Increased physiological dead space/tidal volume ratio during exercise in burned children

Mlcak, Ronald P.; Desai, M. H.; Robinson, Ellen; McCauley, Robert L.; Richardson, Jeannette; Herndon, David N.

doi:10.1016/0305-4179(94)00017-4

Cited by 13 publications

(12 citation statements)

References 1 publication

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“…If this is the case, then rehabilitation exercise medicine may need specific guidelines for burned populations, especially if HR- or oxygen uptake-based training (i.e., percent HR/oxygen uptake max) is used as a guide for exercise prescription. Some have reported that burns do not affect children's exercise tolerance during a graded exercise stress test(20), while others have reported limited endurance exercise due to abnormal lung function at 2 to 3 years post burn (7, 21). …”

Section: Introductionmentioning

confidence: 99%

Children with Burn Injury Have Impaired Cardiac Output during Submaximal Exercise

Rivas

Herndon

Beck³

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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Introduction Burn trauma damages resting cardiac function; however, it is currently unknown if the cardiovascular response to exercise is likewise impaired. We tested the hypothesis that, in children, burn injury lowers cardiac output (Q) and stroke volume (SV) during submaximal exercise. Methods Five children with 49±4% total body surface area (BSA) burned (2 female, 11.7±1 y, 40.4±18 kg, 141.1±9 cm) and eight similar non-burned controls (5 female, 12.5±2 y, 58.0±17 kg, 147.3±12 cm) with comparable exercise capacity (peak oxygen consumption [peak VO2]: 31.9±11 vs. 36.8±8 ml O2·kg·min-1, P=0.39) participated. The exercise protocol entailed a pre-exercise (pre-EX) rest period followed by 3-minute exercise stages at 20 W and 50 W. VO2, heart rate (HR), Q (via non-rebreathing), SV (Q/HR), and arteriovenous O2 difference ([a-v] O2 dif, Q/VO2) were the primary outcome variables. Results Using a 2-way factorial ANOVA (group [G] × exercise [EX]), we found that Q was ∼27% lower in the burned than the non-burned group at 20 W of exercise (burned 5.7±1.0 vs. nonburned: 7.9±1.8 L·min-1) and 50 W of exercise (burned 6.9±1.6 vs. nonburned 9.2 ±3.2 L·min-1) (G × EX interaction, P=0.012). SV did not change from rest to exercise in burned children but increased by ∼24% in the non-burned group (main effect for EX, P=0.046). Neither [a-v] O2 dif nor VO2 differed between groups at rest or exercise, but HR response to exercise was reduced in the burn group (G × EX interaction, P=0.004). When normalized to BSA, SV (index) was similar between groups; however, Q (index) remained attenuated in the burned group (G × EX interaction, P<0.008). Conclusions Burned children have an attenuated cardiovascular response to submaximal exercise. Further investigation of hemodynamic function during exercise will provide insights important for cardiovascular rehabilitation in burned children.

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Section: Introductionmentioning

confidence: 99%

Children with Burn Injury Have Impaired Cardiac Output during Submaximal Exercise

Rivas

Herndon

Beck³

et al. 2017

Medicine &Amp; Science in Sports &Amp; Exercise

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“…Pulmonary function (PF) can be compromised as a result of complications caused by smoke inhalation, direct thermal damage to the respiratory tract, pulmonary edema, and respiratory tract infection 4 ) . Thermal injuries result in a reduction of pulmonary function, which is typified by an initial obstructive pattern of disease lasting up to 2 years and then the restrictive pattern of pulmonary function, which lasts into convalescence, and patients who survive thermal injury might not regain normal cardiopulmonary functions 5 ) .…”

Section: Introductionmentioning

confidence: 99%

Aerobic exercise training in modulation of aerobic physical fitness and balance of burned patients

2015

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[Purpose] This study aimed to determine the impact of aerobic exercise on aerobic capacity, balance, and treadmill time in patients with thermal burn injury. [Subjects and Methods] Burned adult patients, aged 20–40 years (n=30), from both sexes, with second degree thermal burn injuries covering 20–40% of the total body surface area (TBSA), were enrolled in this trial for 3 months. Patients were randomly divided into; group A (n=15), which performed an aerobic exercise program 3 days/week for 60 min and participated in a traditional physical therapy program, and group B (n=15), which only participated in a traditional exercise program 3 days/week. Maximal aerobic capacity, treadmill time, and Berg balance scale were measured before and after the study. [Results] In both groups, the results revealed significant improvements after treatment in all measurements; however, the improvement in group A was superior to that in group B. [Conclusion] The results provide evidence that aerobic exercises for adults with healed burn injuries improve aerobic physical fitness and balance.

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“…Beyond 5 years postburn, adults have a reduced peak VO 2 and time to fatigue compared to nonburned healthy adults 39 and published norms 40 . In addition, some have reported that burned patients have limited exercise endurance due to abnormal lung function at 2 to 3 years postburn 41, 42 . We have recently found that, immediately after hospital discharge, burned children have reduced cardiac output during submaximal exercise (unpublished findings) and exercise aerobic capacity values that are in the very poor (<25 ml O 2 ·kg −1 ·min −1 )-to-poor (25–31 ml O 2 ·kg −1 ·min −1 ) range relative to nonburned children 9, 43 .…”

Section: Discussionmentioning

confidence: 99%

Resting β-Adrenergic Blockade Does Not Alter Exercise Thermoregulation in Children With Burn Injury

Rivas

McEntire²,

Herndon

et al. 2017

Journal of Burn Care & Research

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The objective of this study was to test the hypothesis that propranolol, a commonly prescribed β-blocker to burned children, in combination with exercise-heat stress, increases the risk of heat illness and exercise intolerance. In a randomized double-blind study, propranolol was given to 10 burned children, and placebo was given to 10 additional burned children (matched for TBSA burned; mean ± SD, 62 ± 13%), while nonburned children served as healthy controls. All groups were matched for age and body morphology (11.2 ± 3.0 years; 146 ± 19 cm; 45 ± 18 kg; 1.3 ± 0.4 m2). All children exercised in hot conditions (34.3 ± 1.0°C; 26 ± 2% relative humidity) at 75% of their peak aerobic capacity. At the end of exercise, none of the groups differed for final or change from baseline intestinal temperature (38.0 ± 0.5°C; 0.02 ± 0.01Δ°C·min-1), unburned (37.0 ± 0.6°C) and burned skin temperatures (36.9 ± 0.7°C; nonburn group excluded), heat loss (21 ± 18 W m-2), whole-body thermal conductance (118 ± 113 W m-2), or physiological strain index (5.6 ± 1). However, burn children exercised less than nonburn group (21.2 ± 8.6 vs 30 ± 0.0 min; P < .001) and had a lower calculated exercise tolerance index (1.0 ± 0.0 vs 6.7 ± 4.3; P < .01). Burned children had lower peak heart rates than nonburned children (173 ± 13 vs 189 ± 7 bpm; P < .01), with greater relative cardiac work rates at the end of exercise (97 ± 10 vs 85 ± 11% peak heart rate; P < .01). Resting β-adrenergic blockade does not affect internal body temperature of burned children exercising at similar relative intensities as nonburn children in the heat. Independent of propranolol, a suppressed cardiac function may be associated to exercise intolerance in children with severe burn injury.

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Increased physiological dead space/tidal volume ratio during exercise in burned children

Cited by 13 publications

References 1 publication

Children with Burn Injury Have Impaired Cardiac Output during Submaximal Exercise

Children with Burn Injury Have Impaired Cardiac Output during Submaximal Exercise

Aerobic exercise training in modulation of aerobic physical fitness and balance of burned patients

Resting β-Adrenergic Blockade Does Not Alter Exercise Thermoregulation in Children With Burn Injury

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