Use of clonidine following the weaning phase of the elderly patients underwent elective on-pump cardiac surgery: a prospective randomized study
© Caroleo et al; licensee BioMed Central Ltd. 2010
Published: 19 May 2010
Alpha-2 adrenergic agonists reduce mortality and myocardial infarction following vascular and cardiac surgery . Few data exist about the weaning phase in this setting.
Materials and methods
Design:Analysis of a prospective and randomized collected database.
Setting:Intensive Care Unit (ICU) in an University Hospital.
Patients:A total of 45 patients aged >65 (26 M, 19 F; ASA II-III) submitted to elective on-pump cardiac surgery from November 2007 to June 2008.
Randomization:On ICU admission the patient was assigned to group 1 (Clonidine, intervention group) or group 2 (Placebo, control group).
Interventions:Group 1 received intravenous (IV) bolus of Clonidine 0.5 microg/kg followed by continuous infusion of 1 – 2 microg/kg/hr all over the weaning protocol phase. Group 2 received IV continuous infusion of Sodium Chloride 0.9% all over the weaning phase.
Data collection: We evaluated hemodynamic parameters, Troponin I (TnI) blood levels, weaning parameters, Delirium Detection Score (DDS), weaning duration and ICU length of stay. The patients were evaluated preoperatively (T0), on ICU admission (T1), after 6 hours (T2) and 30 minutes after the start of weaning protocol (T3).
No differences in preoperative and operative variables (p=NS for all measurements). The incidence of postoperative atrial fibrillation was lower in group 1 (p<0.001). Following the weaning phase, Heart Rate, Mean Pulmonary Arterial Pressure and Pulmonary Arterial Occlusion Pressure were lower in group 1 (respectively p<0.001, p=0.019 and p=0.037). The TnI levels was lower in group 1 (p=0.05). The ratio of respiratory rate and tidal volume (RR/TV) and the product of RR and pressure support (RR x PS) were lower in group 1 (both p<0.001); the ratio of PaO2 and FIO2 (PA/FI) and PaCO2 were higher in group 1 (respectively p=0.0035 and p<0.001). DDS was lower in group 1 (p=0.0028). Weaning duration and ICU length of stay were similar in the two groups (p=NS).
The use of Clonidine in this setting reduce the stress-response during the weaning phase, improving hemodynamic stability and myocardial protection.
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