Effect of neuromuscular blockade on oxygen consumption and energy expenditure in sedated, mechanically ventilated children.
OBJECTIVE
To quantify the effects of neuromuscular blockade (NMB) on energy expenditure for intubated, mechanically ventilated, critically ill children.


METHODS
A prospective, unblinded clinical study. Each subject was studied twice, before and after establishment of NMB.


METHODS
A tertiary care pediatric intensive care unit.


METHODS
Critically ill children undergoing mechanical ventilation and receiving ongoing sedation were eligible, if they had a cuffed endotracheal tube and were physiologically stable.


METHODS
A total of 20 children (age, 1 to 15 yrs) were studied in an unblinded, crossover fashion. All were mechanically ventilated via a cuffed endotracheal tube, with ventilator rate and tidal volume adequate to provide complete ventilation, and F(IO2) <0.6. Absence of gas leak around the endotracheal tube was assured, and all patients were sedated using continuous infusions of midazolam and/or fentanyl; no changes in ventilator settings, nutritional input, or inotropic drug dose were permitted during the study period. Each patient underwent indirect calorimetry immediately before establishment of NMB. NMB was then induced, and indirect calorimetry was repeated. Complete blockade was verified using a peripheral nerve stimulator. In each case, the two sets of measurements were completed within a 1-hr period.


RESULTS
Data analyzed included identifying and diagnostic information, oxygen consumption, and carbon dioxide production. Energy expenditure was calculated using standard formulas. Oxygen consumption and energy expenditure values obtained before and after the establishment of NMB were compared by using paired Student's t-test. NMB reduced oxygen consumption from 6.54+/-0.49 mL/kg/min to 5.90+/-0.40 ml/kg/min, and energy expenditure was reduced from 46.5+/-3.7 kcal/kg/24 hrs to 41.0+/-2.8 kcal/kg/24 hrs (p < .001 in each case). The reduction in oxygen consumption was 8.7+/-1.7%, and that in energy expenditure 10.3+/-1.8%, of pre-NMB values, respectively.


CONCLUSIONS
NMB significantly reduces oxygen consumption and energy expenditure in critically ill children who are sedated and mechanically ventilated; the degree of reduction is small.
Vernon
D D
DD
Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84113-1100, USA. don.vernon@hsc.utah.edu
Witte
M K
MK
D000293:Adolescent; D001279:Atracurium / Q000008:administration & dosage / Q000009:adverse effects; D002153:Calorimetry, Indirect; D002648:Child; D002675:Child, Preschool; D016292:Procedural Sedation; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D006801:Humans; D007223:Infant; D015278:Intensive Care Units, Pediatric; D007442:Intubation, Intratracheal; D008297:Male; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage* / Q000009:adverse effects; D010101:Oxygen Consumption / Q000187:drug effects*; D010197:Pancuronium / Q000008:administration & dosage / Q000009:adverse effects; D012121:Respiration, Artificial; D014673:Vecuronium Bromide / Q000008:administration & dosage / Q000009:adverse effects
D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium; D014673:Vecuronium Bromide; D010197:Pancuronium