Intraoperative transesophageal Doppler color flow imaging used to guide patient selection and operative treatment of ischemic mitral regurgitation.

BACKGROUND: Intraoperative transesophageal Doppler color flow imaging (TDCF) affords the opportunity to assess mitral valve competency immediately before and after cardiopulmonary bypass (CPB). The purpose of this study was to assess the utility of TDCF to assist in the selection and operative treatment of ischemic mitral regurgitation (MR). METHODS AND RESULTS: Two hundred forty-six patients undergoing surgery for ischemic heart disease were prospectively studied. All had preoperative cardiac catheterization. Catheterization and pre-CPB TDCF were discordant in their estimation of MR in 112 patients (46%). Compared with patients in whom both techniques agreed in estimation of MR, patients with discordance in MR were more likely to have had unstable clinical syndromes at the time of catheterization (79% versus 40%, p less than 0.05) or to have received thrombolytics (16% versus 8%, p less than 0.05). Pre-CPB TDCF resulted in a change in the operative plan with respect to the mitral valve in 27 patients (11%). Because less MR was found by TDCF than catheterization, 22 patients had only coronary bypass grafting when combined coronary bypass and mitral valve surgery had been planned. Because more MR was found by TDCF than catheterization, five patients had combined coronary bypass and mitral valve surgery when coronary bypass alone had been planned. Unsatisfactory results noted by TDCF following mitral valve surgery in five patients resulted in immediate corrective surgery. Cox regression analysis identified residual MR at the completion of surgery to be an important predictor of survival (chi 2 = 21.4) after surgery--more important than patient age (chi 2 = 8.3) or left ventricular ejection fraction (chi 2 = 5.3). CONCLUSIONS: These results indicate that TDCF is useful in guiding patient selection and operative treatment of ischemic MR and that in such patients, intraoperative TDCF should be performed routinely.

The utility of transesophageal echocardiography and Doppler color flow imaging in patients undergoing cardiac valve surgery.

To assess the value of intraoperative transesophageal echocardiography during cardiac valve surgery, 154 consecutive patients who had a valve operation in conjunction with pre- and postcardiopulmonary bypass transesophageal imaging were studied. Prebypass imaging yielded unsuspected findings that either assisted or changed the planned operation in 29 (19%) of the 154 patients. Imaging immediately after bypass revealed unsatisfactory operative results that necessitated immediate further surgery in 10 (6%) of the 154 patients. Postbypass left ventricular dysfunction, prompting administration of inotropic agents, was identified in 13 patients (8%). Transesophageal echocardiography proved most useful when both two-dimensional and Doppler color flow imaging were employed in patients undergoing a mitral valve operation, where surgical decisions based on echocardiographic results were made in 26 (41%) of 64 cases. Postbypass echocardiographic findings identified patients at risk for an adverse postoperative outcome. Of 123 patients whose postbypass valve function was judged to be satisfactory, 18 (15%) had a major postoperative complication and 6 (5%) died, whereas of 7 patients with moderate residual valve dysfunction, 6 (86%) had a postoperative complication and 3 (43%) died (p less than 0.05 for both). Likewise, of 131 patients with preserved postbypass left ventricular function, 12 (9%) had a major complication and 7 (5%) died, whereas of 23 patients with reduced ventricular function, 17 (73%) had a postoperative complication and 6 (26%) died (p less than 0.05 for both). These data indicate that intraoperative transesophageal echocardiography is useful in formulating the surgical plan, assessing immediate operative results and identifying patients with unsatisfactory results who are at increased risk for postoperative complications.

General anesthesia during percutaneous transluminary coronary angioplasty for acute myocardial infarction: results of a randomized controlled clinical trial.

Acutely ill patients with myocardial infarction may require immediate cardiac catheterization and coronary angioplasty to achieve myocardial reperfusion. To determine the feasibility of using general anesthesia under these circumstances, a randomized clinical trial was performed. Of 50 patients, 25 received anesthesia and 25 receive intravenous sedation. There were transient increases in heart rate and blood pressure after tracheal intubation in the anesthetized patients, followed by significant and sustained decreases below baseline values once steady state anesthesia was attained. Arterial oxygenation was significantly improved in anesthetized patients. There were no serious complications due to anesthesia, but the small sample size limited the power of the study to detect differences in morbidity or mortality. Patients strongly preferred anesthesia. These results show that general anesthesia is feasible in patients undergoing interventional cardiac catheterization during acute myocardial infarction, when pain, anxiety or agitation do not respond adequately to conventional measures.

Noninvasive cardiac monitoring.

During the past few years a number of technological developments have made new methods of noninvasive cardiac monitoring available for use in the intensive care unit. Some of these can be used almost continuously some repeatedly, but intermittently, to manage critically ill patients. In addition to avoiding the risks of pain, bleeding, and infection associated more with invasive studies, a major advantage of many noninvasive studies is that one is able to conduct them at the bedside. Echocardiography has been most useful in this regard, but now even nuclear imaging can be carried out with commercially available portable scanners. Doppler techniques, formerly understood only by those with considerable background in cardiology have now evolved to provide the clinician with a simple method of measuring cardiac output. ECG monitoring too has undergone recent refinements to automate the detection of ST segment changes that escape routine observation of the bedside monitor.

Effect of hypothermia on median nerve somatosensory evoked potentials.

Median nerve somatosensory evoked potentials (SEP) were monitored in ten patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB). Anesthesia was induced and maintained with sufentanil, oxygen, and pancuronium. Esophageal, nasopharyngeal, rectal, and blood temperatures were continuously monitored. SEPs were recorded before induction of anesthesia, after induction, and during cooling and rewarming on CPB. There was a strong negative correlation between SEP latencies and temperature (except rectal) (r = -.91, P < .001). for cortical latency and esophageal temperature. A decrease in esophageal temperature of 1 degrees C resulted in an increase in SEP latency of 1 ms. There was also a weak positive correlation between evoked potential amplitude and temperature (r = .19) for cortical amplitude and esophageal temperature.

Sufentanil pharmacokinetics in pediatric cardiovascular patients.

The pharmacokinetics of sufentanil were studied in 28 pediatric patients undergoing cardiovascular procedures. Patients were divided into four groups on the basis of age: neonates (0-1 month, n = 9), infants (1-24 months, n = 7), children (2-12 yr, n = 7), and adolescents (12-18 yr, n = 5). Sufentanil 10-15 micrograms/kg, was administered by IV bolus and plasma concentrations measured for up to 20 hr. A tri-exponential equation best described the time-concentration data in all patients. Clearance rate (Cl) was 6.7 +/- 6.1 ml.kg-1.min-1 (+/- SD) in neonates, which was significantly lower than the values of 18.1 +/- 2.7, 16.9 +/- 3.2, and 13.1 +/- 3.6 ml.kg-1 min-1 observed in infants, children, and adolescents, respectively. The volume of distribution at steady state (Vdss) was 4.15 +/- 1.0 L/kg in neonates, significantly greater than the values of 2.73 +/- 0.5 and 2.75 +/- 0.5 L/kg observed in children and adolescents, respectively. The elimination half-life (T1/2 beta) was 783 +/- 346 min in neonates, significantly longer than the values of 214 +/- 41, 140 +/- 30, and 209 +/- 23 min observed in infants, children, and adolescents, respectively. The plasma concentration of sufentanil at the time of additional anesthetic supplementation to suppress hemodynamic responses to surgical stimulation was 2.51 ng/ml in neonates, significantly higher than the levels of 1.58, 1.53, and 1.56 ng/ml observed in infants, children, and adolescents, respectively. The authors conclude that age-related differences in pharmacokinetic and pharmacodynamic properties of sufentanil are evident in pediatric patients with major cardiovascular disease who are undergoing cardiovascular surgery.

Intraoperative transesophageal color flow mapping: initial experience.

Transesophageal Doppler color flow mapping (TEDCFM) is a new ultrasound modality now being developed. It provides a convenient, noninvasive way to image cardiac anatomy and intracardiac blood flow that is applicable to intraoperative use. We describe its use in one normal subject and seven cardiac surgical patients. Blood flow characteristics as visualized by TEDCFM are described for these patients. Transesophageal Doppler color flow mapping provided specific information about the presence, site, and severity of mitral regurgitation, aortic regurgitation, and interatrial shunting. Paravalvular leak was detected in one patient after mitral valve replacement. The intimal tear of a type I aortic dissection was located with positive identification of the true and false lumina. A high incidence of mild asymptomatic mitral regurgitation was found in patients undergoing coronary artery bypass grafting (CABG).

Pharmacokinetics of esmolol in anesthetized patients receiving chronic beta blocker therapy.

The pharmacokinetics of esmolol, a new, ultra-short-acting beta adrenergic blocking drug, were studied in 19 patients undergoing coronary artery surgery. Esmolol was administered as a continuous infusion, and blood concentrations were measured at intervals up to 40 min after discontinuation of the infusion. In all patients, a bi-exponential equation best described the esmolol concentration--time curve. Half-lives for the distribution and elimination phases were 1.34 +/- 0.77 min and 9.9 +/- 4.55 min (mean +/- SD), respectively. The mean values for V beta and V epsilon were 1.9 +/- 1.24 l X kg-1 and 0.41 +/- 0.31 l X kg-1, respectively, and the total clearance was 128 +/- 41 ml X kg-1 X min-1.

Hemodynamic effects of esmolol in chronically beta-blocked patients undergoing aortocoronary bypass surgery.

The hemodynamic effects of esmolol were studied in 40 patients scheduled for elective coronary artery surgery to determine whether the administration of esmolol in chronically beta-blocked patients would result in additional attenuation of sympathetically mediated hemodynamic stress responses to noxious stimuli. Patients were randomly assigned to receive IV infusions of esmolol or 5% dextrose in water (D5W). All received their regular dose of beta-adrenergic blocker within 6 hr of surgery and were anesthetized with diazepam, pancuronium, and enflurane. Increases (greater than 25% above baseline) in systolic blood pressure were treated with sodium nitroprusside (SNP). Esmolol was started before induction of anesthesia and continued until 5 min after maximal sternal spread. There were no statistically significant differences between the esmolol and control groups in any hemodynamic parameter during induction, intubation, skin incision, and sternotomy. Only at 5 min after maximal sternal spread was there a statistically significant lower systolic blood pressure in the esmolol-treated group. However the incidence and magnitude of SNP use in the control group was significantly (P less than 0.05) greater. Thus, the lower blood pressure, in the absence of changes in systemic vascular resistance, cardiac index, heart rate, and pulmonary capillary wedge pressure points toward a decrease in myocardial contractility, suggesting that the addition of esmolol to chronically used beta-blockers resulted in an additional negative inotropic effect. We conclude that in patients with coronary artery disease in whom chronic beta-blocker therapy is continued until the time of surgery, esmolol does not further attenuate the heart rate response but does attenuate the increase in blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Alfentanil-oxygen anaesthesia: plasma concentrations and clinical effects during variable-rate continuous infusion for coronary artery surgery.

A variable rate continuous infusion of alfentanil 12.5-50 mg h-1, commenced after tracheal intubation, was used as the sole opioid anaesthetic agent in 14 patients undergoing coronary artery surgery. The infusion rate was adjusted to somatic responses and to maintain a stable systolic arterial pressure. Plasma alfentanil concentrations were determined throughout anaesthesia, including peaks of surgical stress and for 5 h after operation. Before cardiopulmonary bypass (CPB), a mean infusion rate of 36.6 +/- 8.9 mg h-1 minimized the frequency of hypertensive episodes and resulted in high plasma alfentanil concentrations which reached a mean peak, 1.76 +/- 0.46 micrograms ml-1 at maximal sternal spread. After CPB, a slower infusion rate, 6.9 +/- 5.8 mg h-1, afforded cardiovascular stability. Patients recovered consciousness 3.1 +/- 1.4 h after operation at a mean plasma alfentanil concentration of 0.27 +/- 0.13 micrograms ml-1. Apart from clinical response, parameters have not yet been identified which may optimize infusion rates.