Respiratory, metabolic and hemodynamic effects of clonidine in ventilated patients presenting with withdrawal syndrome.
OBJECTIVE
To investigate the respiratory, metabolic and hemodynamic effects of clonidine in ventilated patients presenting with withdrawal syndrome after sedation interruption.


METHODS
Prospective, interventional, single-center study in 30 ventilated ICU patients.


METHODS
Metabolic [oxygen consumption (VO(2)), CO(2) production (VCO(2)), resting energy expenditure (REE)], respiratory [minute ventilation (V (E)), tidal volume (V (T)), respiratory rate (RR)] and hemodynamic (HR, SAP, MAP) parameters were measured in 30 ventilated ICU patients. Measurements were performed first under sedation with remifentanil-propofol, then after sedation interruption, and finally after clonidine administration (0.9-1.8 mg of clonidine in two doses of 10 min interval).


RESULTS
Sedation interruption produced significant increases in the hemodynamic parameters (SAP and MAP by 33%, HR by 37%), and metabolic rate (increase in VO(2) by 70%, VCO(2) by 88% and REE by 74%), leading to high respiratory demands (increase in V (E) from 9 to 15 l/min). The V (E) was increased due to a twofold increase in the RR; V (T) remained constant. In 25 out of 30 patients, clonidine administration decreased the hemodynamic (SAP, MAP and HR), metabolic (VO(2), VCO(2), REE) and respiratory parameters to values close to those observed with sedation. Clonidine induced mild sedation and patients became more cooperative with the ventilator. All patients responding to clonidine were weaned from the ventilator in 2 days (median, range 1-18 days).


CONCLUSIONS
Patients with withdrawal syndrome had significantly elevated hemodynamic, metabolic and respiratory demands. Clonidine significantly decreased these demands, induced mild sedation and facilitated patient cooperation with the ventilator, enabling ventilator weaning.
Liatsi
Domniki
D
ICU, Papageorgiou General Hospital, Thessaloniki, Greece.
Tsapas
Basilis
B
Pampori
Smaro
S
Tsagourias
Matthew
M
Pneumatikos
Ioannis
I
Matamis
Dimitrios
D
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology* / Q000627:therapeutic use*; D000328:Adult; D002153:Calorimetry, Indirect; D002245:Carbon Dioxide / Q000378:metabolism*; D003000:Clonidine / Q000494:pharmacology* / Q000627:therapeutic use*; D004562:Electrocardiography; D004734:Energy Metabolism; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D006993:Hypnotics and Sedatives; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects*; D010880:Piperidines / Q000008:administration & dosage; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies; D000077208:Remifentanil; D012121:Respiration, Artificial / Q000379:methods*; D012131:Respiratory Insufficiency / Q000453:epidemiology / Q000628:therapy*; D012146:Rest; D013375:Substance Withdrawal Syndrome / Q000453:epidemiology* / Q000209:etiology*; D013610:Tachycardia / Q000188:drug therapy*; D015300:Ventilator Weaning
D000316:Adrenergic alpha-Agonists; D006993:Hypnotics and Sedatives; D010880:Piperidines; D002245:Carbon Dioxide; D003000:Clonidine; D000077208:Remifentanil; D015742:Propofol