Impact of clonidine administration on delirium and related respiratory weaning after surgical correction of acute type-A aortic dissection: results of a pilot study.

Delirium and transient neurologic dysfunctions (TND) often complicate the postoperative course after surgery for acute type-A aortic dissection (AAD). We evaluated the role of clonidine on neurological outcome and respiratory function in 30 consecutive patients undergoing surgery for AAD. Patients were prospectively randomized to receive either clonidine (0.5 microg/kg bolus, followed by continuous infusion at 1-2 microg/kg/h) or placebo (NaCl 0.9%) in on starting and throughout the weaning period from the mechanical ventilation. Incidence of delirium and TND, Delirium Detection Score (DDS), weaning parameters [respiratory rate to tidal volume ratio - f/VT; pressure-frequency product (PFP); partial pressure of arterial oxygen to fractional inspired oxygen concentration (PaO(2)/FiO(2)); partial pressure of carbon dioxide (PaCO(2))], weaning duration and intensive care unit (ICU) length of stay were recorded. The two groups were similar for preoperative and operative variables and also for the incidence of postoperative complications. DDS was lower in the clonidine group (P<0.001). Patients weaned with clonidine showed lower f/VT and PFP, higher PaO(2)/FiO(2) and PaCO(2), lower DDS, weaning period and the related ICU length of stay (P<0.001). This was further confirmed in patients developing delirium/TND. Intravenous clonidine after surgery for AAD reduces the severity of delirium, improves the respiratory function, shortens the weaning duration and the ICU length of stay.

In vivo functional flowmetric behavior of the radial artery graft: is the composite Y-graft configuration advantageous over conventional aorta-coronary bypass?

INTRODUCTION: Intraoperative flowmetric results of different configurations (Y-graft or aorta-coronary) of radial artery grafts have been poorly investigated. METHODS: We report the results of an observational study designed to analyze transit-time flow measurements at baseline and during 1:1 intra-aortic balloon pumping in 114 consecutive patients receiving the radial artery as a aorta-coronary bypass (group A, 72 patients) or as a Y-graft with the left internal thoracic artery (group B, 42 patients). Graft flow reserve, recruited by 1:1 intra-aortic balloon pumping) greater than 1 indicated recruitment of surplus graft flow. Results were stratified by grafted territory and surgical technique. RESULTS: Hospital outcome was comparable. Baseline transit-time flow results were similar between the 2 groups in terms of maximum diastolic flow, minimum systolic flow, mean flow, and pulsatility index. Graft flow reserve was not recruited by intra-aortic balloon pumping in 3 (2.7%) malfunctioning single aorta-oronary radial artery bypass grafts (P = .005 versus successful radial artery bypass grafts). Graft flow reserve was recruited (>1) by intra-aortic balloon pumping in the remaining 111 patent radial artery bypass grafts. Y-grafts showed higher maximum diastolic flow P < .0001), mean flow (P < .0001), graft flow reserve (P < .0001), percentage improvement of maximum diastolic flow (P < .0001), and of mean flow (P < .0001) compared with aorta-coronary radial artery bypass grafts. These results were confirmed for the right coronary (P < or = .004) and the circumflex territory (P < or = .001), for off-pump (P < or = .008) or cardiopulmonary bypass (P < .0001) and for patients undergoing isolated bypass grafting (P < .0001). CONCLUSIONS: Intraoperative flows of radial artery bypass grafts showed comparable baseline results in single aorta-coronary conduits and Y-grafts. Graft flow reserve recruited by intra-aortic balloon pumping was higher in Y-conduits, regardless of the grafted territory and the perfusion strategy chosen. Failed radial artery bypass grafts did not improve transit-time flow results during 1:1 intra-aortic balloong pumping nor showed any recruitment of graft flow reserve.

Off-pump coronary artery bypass surgery versus standard linear or pulsatile cardiopulmonary bypass: endothelial activation and inflammatory response.

OBJECTIVE: Poor outcomes after coronary artery bypass grafting (CABG) have been linked to perioperative endothelial activation and systemic inflammatory responses. The use of pulsatile cardiopulmonary bypass (PCPB) or off-pump CABG (OPCABG) may minimise these phenomena. We compared biochemical and clinical outcomes among patients who underwent CABG with PCPB, CABG with linear CPB (LCPB) or OPCABG. METHODS: Sixty consecutive patients undergoing isolated elective CABG were prospectively randomised trial to receive pulsatile CPB (group A, 20 patients), linear CPB (group B, 20 patients) or OPCABG (group C, 20 patients). Levels of proinflammatory cytokines (interleukins-2, -6, and -8), anti-inflammatory cytokines (interleukin-10) and endothelial markers (vascular endothelial growth factor (VEGF), monocyte chemo-attractant protein (MCP)-1) were measured before, during and after surgery. RESULTS: VEGF and MCP-1 levels increased significantly during surgery in all groups, but they increased the least and were the lowest overall with OPCABG. They rose most and peaked overall with LCPB. Interleukin-2 levels remained stable during OPCABG but decreased equally during PCPB and LCPB. Interleukin-6 and -8 levels rose significantly during both types of CPB versus OPCABG. Interleukin-10 levels increased significantly in all groups during surgery, but they rose least and were the lowest overall with OPCABG and rose most and were the highest overall with PCPB. Intubation times, intensive care unit (ICU) stay and hospital stay were significantly longer in the LCPB group than the other two groups. CONCLUSIONS: LCPB appears to promote endothelial activation and cytokine secretion, which may delay recovery. OPCABG was associated with slight endothelial activation and cytokine response. PCPB significantly attenuates endothelial/cytokine leakage, resulting in hospital outcomes comparable with those after OPCABG.