title: Cardio-respiratory response to moderate chloral hydrate sedation in young lambs.
abstract: OBJECTIVE
  Chloral hydrate (CH) is the most commonly used sedative for medical procedures and lung function tests in infancy. The aim was to determine whether moderate CH sedation affects airway function, lung volume and ventilation.
  
  
  METHODS
  Thirteen chronically instrumented 7- to 8-week-old lambs were studied both before and after CH sedation (50 mg/kg as intravenous bolus followed by 25 mg/kg/hour as continuous infusion). Nitrogen washout technique and lung mechanics analysis were used to assess functional residual capacity (FRC) and airway function. Moment analysis and lung clearance index were calculated as measures of gas mixing efficiency in distal airways. Respiratory rate, tidal volume, minute ventilation and indices of inspiratory drive were determined together with heart rate, blood pressure and oxygenation.
  
  
  RESULTS
  No significant CH-induced changes were found for gas mixing efficiency, FRC or lung mechanics. Minute ventilation decreased slightly, but significantly, while indices of inspiratory drive remained unchanged. Heart rate increased significantly, but mean arterial blood pressure was unaffected.
  
  
  CONCLUSIONS
  Moderate CH sedation did not significantly affect airway function or FRC. Although indices of inspiratory drive were not affected, minute ventilation decreased slightly. These findings indicate that reliable results can be obtained from lung function testing when CH is used for sedation.
authors.affiliation: Department of Paediatrics, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden. kenneth.sandberg@vgregion.se
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Sandberg
authors.forename: Stanley D
authors.initials: SD
authors.lastname: Poole
authors.forename: Håkan W
authors.initials: HW
authors.lastname: Sundell
mesh_terms: D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects*; D002697:Chloral Hydrate / Q000008:administration & dosage* / Q000494:pharmacology; D004195:Disease Models, Animal; D005333:Fetus / Q000187:drug effects; D005652:Functional Residual Capacity / Q000187:drug effects*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology; D007262:Infusions, Intravenous; D008168:Lung / Q000187:drug effects* / Q000502:physiology; D009538:Nicotine / Q000009:adverse effects; D012119:Respiration / Q000187:drug effects*; D012129:Respiratory Function Tests / Q000379:methods; D034561:Sheep, Domestic
chemical_list: D006993:Hypnotics and Sedatives; D002697:Chloral Hydrate; D009538:Nicotine
keywords: Control of breathing; Distal airway function; Minute ventilation; Respiratory mechanics