Increased cerebrovascular resistance after retrograde cerebral perfusion: a Doppler study.

Deep hypothermic circulatory arrest (DHCA) with retrograde cerebral perfusion (RCP) under high central venous pressure (CVP) is often used in aortic arch surgery under cardiopulmonary bypass (CPB). We hypothesized that DHCA with RCP under high CVP causes cerebral vascular compression because of increased perivascular pressure due to extravasation of fluid into intracranial tissue. In a retrospective study, we evaluated the pulsatility index (PI) and resistance index (RI) of the internal carotid arteries (ICA) and external carotid arteries (ECA) before and after CPB in 15 patients who underwent DHCA/RCP (group 1) and 17 patients who underwent regular CPB without DHCA/RCP (group 2). Both indices are known to reflect vascular resistance distal to the measurement point. The PI and RI of the ICA increased significantly after the procedure in group 1 but did not change in group 2. The PI and RI of the ECA did not change in either group. In group 1, the rate of increase in PI and RI correlated with the duration of RCP, which was significantly higher in patients who had postoperative delirium than in patients who did not experience postoperative delirium. As increases in PI/RI after DHCA/RCP occurred only in the ICA, we concluded that the changes were due to compression of vessels as a result of increased perivascular pressure. The greater increase in the PI/RI in patients who experienced postoperative delirium indicates that increased perivascular pressure plays a role in the occurrence of postoperative delirium after DHCA/RCP.

Impact of diabetic retinopathy on cardiac outcome after coronary artery bypass graft surgery: prospective observational study.

BACKGROUND: Diabetic retinopathy is a manifestation of more severe diabetes. We sought to assess the impact of diabetic retinopathy on cardiac outcome of coronary artery bypass graft surgery (CABG). METHODS: We prospectively assessed the status of the retina of 74 consecutive diabetics who were referred for first-time CABG, and compared cardiac outcome of CABG in diabetics with retinopathy with that in those without retinopathy. Cardiac events included recurrent angina or congestive heart failure that needed admission to hospital, myocardial infarction, repeat revascularization, and cardiac death. RESULTS: Twenty-six diabetics had retinopathy and 48 diabetics did not have retinopathy. Diabetics with retinopathy were likely to have higher hemoglobin A1c level (p = 0.048), and receive insulin treatment (p = 0.0065). In the 12 months of follow-up, 13 cardiac events occurred in diabetics with retinopathy and 7 in those without retinopathy (p = 0.0021). Among diabetics with retinopathy, heart failure or death due to heart failure accounted for 54% (7 of 13) of these cardiac events. Kaplan-Meier analysis showed significant difference in cardiac event-free survival between the two groups (p < 0.001). After adjustment for differences in patients' characteristics, diabetic retinopathy remained a predictor of cardiac event (adjusted relative risk = 4.2, 95% confidence interval, 1.5% to 11.9%; p = 0.0067). CONCLUSIONS: After CABG, diabetics with retinopathy have a substantially increased risk of cardiac events, especially of congestive heart failure.

[Sinus arrest during laryngoscopy for induction of general anesthesia with intravenous fentanyl and propofol].

A 43-year-old woman with Plummer's disease underwent left thyroid lobectomy without premedication using ambulatory electrocardiogram monitoring under general anesthesia. Anesthesia was induced with an intravenous bolus of fentanyl 100 microg, lidocaine 40 mg, propofol 80 mg and vecuronium 7 mg. As she moved 5 min after induction of anesthesia, fentanyl 100 microg and propofol 30 mg were administered additionally. After positive pressure ventilation by mask for 8 min, heart rate decreased from 71 beats x min(-1) to 48 beats x min(-1), and laryngoscopy was performed. When the tip of the laryngoscope was pressed on the base of the tongue and on lifting the epiglottis, the electrocardiogram showed RR interval prolongation and gradually going to sinus arrest. The laryngoscope was removed immediately and mask ventilation was performed. The heart beat resumed at 5.5 sec after sinus arrest. Atropine 0.5 mg was given intravenously and heart rate increased to 50 beats x min(-1). Additionally atropine 0.25 mg increased heart rate to 70 beats x min(-1). The second laryngoscopy was performed uneventfully. We consider this phenomenon as a result of vagovagal reflex. Fentanyl and propofol, by reducing sympathetic tone to a greater extent than parasympathetic tone, decrease blood pressure and heart rate, and predispose to a parasympathetic response for noxious stimulation. This case indicates that intravenous injection of atropine must be immediately used for bradycardia during laryngoscopy for induction of general anesthesia with fentanyl and propofol.

Usefulness of unipolar epicardial ventricular electrogram for triggering of intraaortic balloon counterpulsation during off-pump coronary artery bypass surgery in patients with hemodynamic instability complicating acute coronary syndromes.

During off-pump coronary artery bypass graft (CABG) surgery for patients requiring preoperative intraaortic balloon counterpulsation (IABP) support, errors in timing of IABP during mobilization of the heart can induce unstable hemodynamic conditions. We applied a simple technique for triggering IABP accurately during off-pump CABG: one end of an epicardial pacemaker wire is placed on the surface of the left ventricle, and the other end is linked to one of the precordial V leads. This technique provided an exact detection of R-wave potentials in any position of the heart during the off-pump CABG procedure. Ten patients with hemodynamic instability complicating acute coronary syndromes underwent off-pump CABG with this technique, including grafting to the circumflex system, safely and successfully.

A simple method of triggering balloon counterpulsation accurately during off-pump coronary artery bypass surgery.

With increasing experience, off-pump coronary artery bypass grafting for high-risk patients can be performed safely. However, in patients who need intraaortic balloon counterpulsation support, mistriggering of intraaortic balloon counterpulsation during mobilization of the heart can induce unstable hemodynamic conditions. My colleagues and I have developed a simple method of detecting the trigger signal accurately: an epicardial pacemaker wire is placed close to the apex of the left ventricle, and 1 precordial V lead is disconnected and then linked to the epicardial pacemaker wire. This method provides an excellent detection of R-wave potentials in any position of the heart throughout an entire off-pump coronary artery bypass grafting procedure.