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Perioperative management of implantable cardioverter-defibrillators is an important part of anesthetic care. Society recommendations and expert consensus statements exist to aid clinicians, and they have identified the umbilicus as an important landmark in decision-making. Implantable cardioverter-defibrillator antitachycardia therapy may not need to be deactivated for infraumbilical surgery because electromagnetic interference is unlikely to occur. The authors present two cases in which inappropriate antitachycardia therapy occurred intraoperatively with use of an underbody dispersive electrode, even though both surgeries were infraumbilical. The authors also present two cadaver models to demonstrate how monopolar electrosurgery below the umbilicus is sensed using both traditional and underbody dispersive electrosurgical return electrodes.

To compare the standard intraluminal approach with the placement of the 9-French Arndt endobronchial blocker with an extraluminal approach by measuring the time to positioning and other relevant intraoperative and postoperative parameters.A prospective, randomized, controlled trial.University hospital.The study comprised 41 patients (20 intraluminal, 21 extraluminal) undergoing thoracic surgery.Placement of a 9-French Arndt bronchial blocker either intraluminally or extraluminally. Comparisons between the 2 groups included the following: (1) time for initial placement, (2) quality of isolation at 1-hour intervals during one-lung ventilation, (3) number of repositionings during one-lung ventilation, and (4) presence or absence of a sore throat on postoperative days 1 and 2 and, if present, its severity.Median time to placement (min:sec) in the extraluminal group was statistically faster at 2:42 compared with 6:24 in the intraluminal group (p0.05). Overall quality of isolation was similar between groups, even though a significant number of blockers in both groups required repositioning (extraluminal 47%, intraluminal 40%, p0.05), and 1 blocker ultimately had to be replaced intraoperatively. No differences in the incidence or severity of sore throat postoperatively were observed.A statistically significant reduction in time to placement using the extraluminal approach without any differences in the rate of postoperative sore throat was observed. Whether placed intraluminally or extraluminally, a significant percentage of Arndt endobronchial blockers required at least one intraoperative repositioning.

Study Objective. To assess the effect of substituting dexmedetomidine for propofol during a nationwide propofol shortage on postoperative time to extubation and opioid requirements in patients who underwent coronary artery bypass graft (CABG) surgery. Design. Retrospective case-control study. Setting. Single-center cardiothoracic intensive care unit (ICU) in a tertiary academic medical center. Patients. Seventy adults undergoing isolated, primary, elective CABG who received dexmedetomidine between April 1 and June 30, 2010, during the propofol shortage (35 patients [cases]) or who received propofol between January 1 and March 31, 2010, or between July 1 and September 30, 2010 (35 patients [controls]) for postoperative sedation were included. Patients in the dexmedetomidine group were matched 1:1 to patients in the propofol group based on age, sex, weight, number of vessels bypassed, preoperative ejection fraction, cardiopulmonary bypass time, and aortic cross-clamp time. Measurements and Main Results. The primary outcome consisted of opioid requirements in the first 12 hours after arrival to the ICU in the dexmedetomidine- and propofol-treated patients. Secondary outcomes included the time to extubation (from ICU admission until extubation) and opioid requirements in the first 24 hours. No significant demographic differences were noted between treatment groups. Median opioid requirements in the first 12 hours, as measured by morphine equivalents, were 8.0 mg in the propofol group and 7.0 mg in the dexmedetomidine group (p=0.1). Similarly, at 24 hours, opioid requirements were 16.7 and 17.3 mg in the propofol and dexmedetomidine groups, respectively (p=0.4). The time to extubation demonstrated that patients in the propofol group were extubated at a median of 300 minutes and patients in the dexmedetomidine group were extubated at a median of 318 minutes after ICU arrival (p=0.5). Conclusion. No statistically significant differences were noted between the propofol and dexmedetomidine groups when assessing the outcomes of opioid requirements and the time to extubation. A multicenter, prospective, randomized, blinded study is needed to determine the optimal sedative after CABG surgery.

The management of patients with coronary artery stents during the perioperative period is one of the most important patient safety issues clinicians confront. Perioperative stent thrombosis is a life-threatening complication for patients with either bare-metal or drug-eluting stents. Noncardiac surgery appears to increase the risk of stent thrombosis, myocardial infarction, and death, particularly when patients undergo surgery early after stent implantation. The incidence of complications is further increased when dual-antiplatelet therapy is discontinued preoperatively. It is generally agreed that aspirin must be continued throughout the perioperative period, except in circumstances when the risk of bleeding significantly outweighs the benefit of continued anticoagulation, such as procedures performed in a closed space. We present considerations for regional anesthesia, as well as postoperative recommendations as the occurrence of perioperative stent thrombosis appears to be greatest during this period. Immediate percutaneous coronary intervention is the definitive treatment for perioperative stent thrombosis, and 24-h access to an interventional cardiology suite should be readily available. Algorithms for perioperative management of patients with bare-metal and drug-eluting stents are proposed.

Objective: To evaluate the use of a high dose of nitroglycerin (NTG) for prophylaxis against myocardial ischemia and infarction in patients undergoing coronary artery bypass graft (CABG) surgery with accelerated recovery. Design: Prospective, double-blind, placebo-controlled randomized study. Setting: A university-based medical center. Participants: Forty adult patients presenting for elective CABG surgery. Interventions: Forty patients were divided into 2 blinded study groups. Twenty patients received 2 μg/kg/min of NTG starting before induction of anesthesia and continuing for 6 hours after extubation in the intensive care unit. The placebo group (n = 20) received normal saline during this same interval. Measurements and Main Results: Hemodynamics, incidence and severity of myocardial ischemia, and myocardial infarction rates were determined. There were no differences in hemodynamic parameters between groups. The incidence of ischemia was approximately 35 in each group. Myocardial infarction (as determined by elevated creatine kinase—MB fraction, troponin I, and electrocardiogram criteria) was 10% in the placebo group and 5 in the NTG group (p = 0.234). Conclusions: This study shows a high incidence of myocardial ischemia and infarction in patients presenting for CABG surgery with an accelerated recovery management scheme. NTG was well tolerated clinically; however, it was not found to be protective against myocardial ischemia or infarction in this setting. Copyright © 2000 by W.B. Saunders Company

Background Patients may receive more than one positive inotropic drug to improve myocardial function and cardiac output, with the assumption that the effects of two drugs are additive. The authors hypothesized that combinations of dobutamine and epinephrine would produce additive biochemical and hemodynamic effects. Methods The study was performed in two parts. Phase 1 used human lymphocytes in an in vitro model of cyclic adenosine monophosphate (cAMP) generation in response to dobutamine (10(-8) to 10(-4) M) or epinephrine (10(-9) M to 10(-5) M), and dobutamine and epinephrine together. Phase 2 was a clinical study in patients after aortocoronary artery bypass in which isobolographic analysis compared the cardiotonic effects of dobutamine (1.25, 2.5, or 5 microg x kg(-1) x min(-1)) or epinephrine (10, 20, or 40 ng x kg(-l) x min(-1)), alone or in combination. Results In phase 1, dobutamine increased cAMP production 41%, whereas epinephrine increased cAMP concentration approximately 200%. However, when epinephrine (10(-6) M) and dobutamine were combined, dobutamine reduced cAMP production at concentrations between 10(-6) to 10(-4) M (P = 0.001). In patients, 1.25 to 5 microg x kg(-1) x min(-1) dobutamine increased the cardiac index (CI) 15-28%. Epinephrine also increased the CI with each increase in dose. However, combining epinephrine with the two larger doses of dobutamine (2.5 and 5microg x kg(-1) x mi(-1)) did not increase the CI beyond that achieved with epinephrine and the lowest dose of dobutamine (1.25 microg x kg(-1) x min(-1)). In addition, the isobolographic analysis for equieffective concentrations of dobutamine and epinephrine suggests subadditive effects. Conclusions Dobutamine inhibits epinephrine-induced production of cAMP in human lymphocytes and appears to be subadditive by clinical and isobolographic analyses of the cardiotonic effects. These findings suggest that combinations of dobutamine and epinephrine may be less than additive.

Cloricromene is a coumarin derivative without anticoagulant activities that has recently been found to decrease myocardial infarct size after an ischemic-reperfusion injury. This study seeks to determine when the cardioprotective action of cloricromene is exerted in an in vivo rabbit model of ischemic-reperfusion injury. Forty-nine rabbits subjected to 30 min of coronary occlusion and 120 min of reperfusion were randomized into five groups: VEH (n = 11) received saline vehicle; IR (n = 9) received an infusion of cloricromene starting at the onset of ischemia at 8 micrograms.kg-1.min-1; R(-5)(n = 9) and R(+30)(n = 9) received an infusion of cloricromene at 8 micrograms.kg-1.min-1 starting 5 min before reperfusion and 30 min after reperfusion, respectively; and RB(-5)(n = 11) received 300 micrograms/kg bolus of cloricromene 5 min before reperfusion followed by an infusion of 8 micrograms.kg-1.min-1. All infusions were continued until the end of the reperfusion period. Myocardial infarct size was significantly reduced in groups IR, R(-5), and RB(-5). We conclude that cloricromene's effective time of action occurs prior to the first 30 min of the reperfusion period.

Background Dopexamine and dobutamine are traditionally described as having primarily β 2 -adrenergic agonist properties; norepinephrine is generally classified as β 1 -selective; and epinephrine, isoproterenol, and dopamine are considered mixed β 1 - and β 2 receptor agonists. Much of this selectivity is designated from studies conducted with intact cardiovascular systems in which indirect actions (eg, norepinephrine release from presynaptic nerve terminals) are not separated from direct agonist-receptor interactions. Objective To assess the relative efficacy and potency of dopamine, dobutamine, dopexamine, epinephrine, isoproterenol, and norepinephrine for directly stimulating cyclic adenosine monophosphate (cAMP) production in human lymphocytes, a model of β 2 -adrenoceptor function. Design Open-label, prospective paired studies of lymphocytes from nine healthy human volunteers (seven men). Setting Experimental laboratory of a large, university-affiliated medical center. Interventions Concentration-response curves were generated for each adrenergic agonist; maximal cAMP production was used to compare efficacy. For the agonists that more than doubled basal cAMP concentrations, EC 50 calculations were used to compare potency. Measurements and main results Isoproterenol and epinephrine produced the greatest concentrations of cAMP of the agonists tested. cAMP production was increased by isoproterenol at concentrations 1/10 to 1/10,000 that of the other agonists. Norepinephrine stimulated cAMP production only one third as much as epinephrine and isoproterenol, but more than double the level of dopamine, dobutamine, and dopexamine. EC50 concentrations for norepinephrine were 10-fold higher than epinephrine and 50-fold higher than isoproterenol. Conclusions Epinephrine and isoproterenol are the most efficacious and potent direct-acting β 2 -adrenergic receptor agonists using this lymphocyte cAMP model. Norepinephrine exhibits significant effects on the β-receptors on lymphocytes, suggesting β 2 -adrenoceptor effects with high concentrations of this drug. The very low cAMP levels generated by dopamine, dobutamine, and dopexamine (even in high concentrations) support other evidence that these agents have little direct effect on the β 2 -adrenoceptor.

Milrinone can reverse acute postischemic myocardial dysfunction after cardiopulmonary bypass, although neither the appropriate bolus dose nor its pharmacokinetics has been established for cardiac surgical patients. Consenting patients undergoing cardiac surgery received milrinone (25, 50, or 75 micrograms/kg) in an open-label, dose-escalating study if their cardiac index was3 L.min-1.m-2 after separation from bypass. Heart rate, mean arterial blood pressure, pulmonary capillary wedge pressure, and cardiac index were determined before and after the administration of milrinone. Timed blood samples were obtained for measurement of milrinone plasma concentrations and pharmacokinetic analysis. Twenty-nine of 60 consenting patients had cardiac indices3 L.min-1.m-2 after separation from bypass, received milrinone, and completed the protocol. All three bolus doses of milrinone significantly increased cardiac index. The 50- and 75-micrograms/kg doses produced significantly larger increases in cardiac index than the 25-micrograms/kg dose; however, the 75-micrograms/kg dose did not produce a significantly larger increase in cardiac index than did the 50-micrograms/kg dose. Two of 10 patients receiving milrinone 25 micrograms/kg, but no patient receiving either 50 or 75 micrograms/kg, required early epinephrine rescue when the cardiac index failed to increase by15%. The 75-micrograms/kg dose was associated with a case of ventricular tachycardia. The three-compartment model better described milrinone drug disposition than the two-compartment model by both visual inspection and Schwartz-Bayesian criterion. There was only limited evidence of dose-dependence, so data from all three doses are reported together (and normalized to the 50-micrograms/kg dose). Data from one patient was discarded (samples mislabeled). Using mixed-effects nonlinear regression (for n = 28), the following volumes were determined for the three compartments: V1 = 11.1 L, V2 = 16.9 L, and V3 = 363 L. Similarly, the following clearances were estimated for the three compartments: Cl1 = 0.067 L/min, Cl2 = 1.05 L/min, and Cl3 = 0.31 L/min. The 50-micrograms/kg loading dose appeared more potent than the 25-micrograms/kg dose, and, as potent, but with possibly fewer side-effects than the 75-micrograms/kg dose. The short context-sensitive half-times of 6.7 or 10.2 min after 1- or 10-min bolus infusions underscore the need for prompt institution of a maintenance infusion when milrinone concentrations must be maintained.(ABSTRACT TRUNCATED AT 400 WORDS)

Background Triiodothyronine regulates cardiac contractility; however, the mechanisms by which it produces its acute contractile effects remains unknown. We compared the acute effects of thyroid hormones (triiodothyronine [T3] and thyroxine [T4]) and of isoproterenol on the contractility of isolated rat hearts. In addition, we sought to determine whether the acute inotropic effects of thyroid hormones were mediated by beta-adrenergic receptors or by increased production of cyclic-3',5'-adenosine monophosphate (cAMP). Methods A Langendorff heart preparation harvested from euthyroid male Sprague-Dawley rats was used. Drugs were administered through an aortic perfusion catheter. A pressure-transduced left-ventricular balloon catheter measured pressure and heart rate changes. Changes in the maximum positive rate of change in pressure (dP/dT) and maximum negative dP/dT were determined. Responses to varying doses of T3, T4, and isoproterenol were assessed in the presence and absence of beta-adrenergic receptor blockade with propranolol. cAMP production, measured by radioimmunoassay, was determined in myocardial cell suspensions after incubation with T3 or isoproterenol. Results T3 0.74 nmol rapidly and significantly increased maximum dP/dT by 335 +/- 38 mmHg/s within 30 s after bolus injection; however, contractility was unchanged after as much as 12.9 nmol T4. The maximal increase in dP/dT after 0.8 nmol isoproterenol was comparable to that produced by T3. However, the cardiotonic actions of isoproterenol were significantly slower to develop (peaking at 60 vs. 15 s) and lasted longer than those of T3. Pretreatment with propranolol 1 mumol diminished the contractile effects of isoproterenol but had no effect on those of T3. Concentrations of isoproterenol that increase contractility also significantly increased cAMP production in isolated rat myocardial cells. However, T3 failed to increase cAMP production. Conclusions These results demonstrate that the acute inotropic effects of T3 are not shared by T4 and appear unrelated to beta-adrenergic receptor mechanisms or to generation of cAMP. Thus, T3 acutely stimulates cardiac contraction by mechanisms that differ from those of the more commonly used beta-adrenergic receptor agonists and phosphodiesterase inhibitors. Further studies are needed to identify the mechanisms underlying the acute contractile effects of T3 and to determine whether T3 will prove useful for increasing ventricular function in patients.

Study objective To evaluate the efficacy of amrinone for facilitating weaning from cardiopulmonary bypass (CPB). Design Prospective, randomized, double-blind, placebo-controlled trial with epinephrine as “rescue” therapy. Setting Operating room of a large, metropolitan tertiarycare center. Patients Thirty-nine patients with preoperative left ventricular dysfunction undergoing cardiac surgery. Thirty-three patients underwent aortocoronary bypass grafting; six patients underwent valve replacement for severe mitral or aortic regurgitation. Interventions Patients received either amrinone (1.5 mg/kg loading dose plus 10 µg/kg/min maintenance infusion; n = 20) or placebo (n = 19) in a randomized double-blind fashion shortly (median, 10.5 min; range, 2 to 24 min) before separation from CPB. Inotropic drugs (other than the study drug) were withheld prior to separation from CPB unless safety considerations demanded that the protocol be broken. Patients who could not be weaned from CPB, as well as those with a cardiac index of 2.2 L/min/m 2 or less after weaning from CPB, received epinephrine (60 to 120 ng/kg/min) by infusion. Measurements and results Fourteen of 19 patients receiving placebo but only 1 of the 20 patients receiving amrinone (p = 0.00001) required epinephrine infusion to separate from bypass. The cardiac index of 4 patients receiving placebo (but no patients with amrinone) failed to exceed 2.2 L/min/m 2 despite epinephrine infusion, requiring the protocol to be broken (p Conclusions Amrinone by itself is an effective agent to facilitate weaning from CPB, and therapy with amrinone reduced the need for individualized titration of epinephrine. Amrinone is as effective as individualized titration of epinephrine (after CPB) to improve cardiac function. Patients in the group receiving amrinone had no greater need for vasoconstricting agents than did patients in the group receiving placebo; however, proactive administration of amrinone before separation from CPB appears to offer no greater benefit to high-risk patients than selective administration of drugs (epinephrine) only to those patients who demonstrate the need for drug support at the time of weaning.

Clinical myocardial dysfunction following cardiopulmonary bypass commonly occurs in patients with good preoperative ventricular function. Following separation from cardiopulmonary bypass, ventricular function improves initially, but then begins to worsen and reaches a nadir between 4 and 6 hours after surgery with full recovery occurring around 24 hours postoperatively. However, in patients with preoperative ventricular dysfunction, the depression of ventricular function is more severe and recovery is longer. Despite this high frequency of myocardial dysfunction, many patients do well without requiring pharmacologic intervention after cardiopulmonary bypass to augment contractility and peripheral perfusion. Factors that may predict the need for inotropic support in patients following cardiopulmonary bypass include low ejection fraction, older age, cardiac enlargement, female sex, the length of cardiopulmonary bypass and the duration of aortic cross-clamping. The patient with preoperative ventricular dysfunction has many of these preoperative and intraoperative predictors for inotropic support. The pharmacologic regimen to support the myocardium during the recovery period following cardiopulmonary bypass must take into consideration the pathophysiologic processes of chronic congestive heart failure and reperfusion injury. Reduction of cyclic adenosine monophosphate (cAMP) levels is a fundamental problem in congestive heart failure and results from either down-regulation of beta-receptors or a defect in the G-regulatory proteins controlling adenylyl cyclase production. This diminishes the effectiveness of agents dependent on cAMP to produce an inotropic response. However, amplification of the reduced cAMP produced by beta-agonists may occur in association with the inhibition of cAMP breakdown resulting from phosphodiesterase inhibitors. All inotropic agents are usually effective in reversing the reperfusion-induced stunned myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Inotropic drugs are administered to improve cardiac performance and increase oxygen delivery to the tissues. These agents, however, also possess a variety of adverse effects. This article discusses the role of phosphodiesterase inhibitors, digitalis, beta-adrenergic agonists (dopamine, epinephrine, and dobutamine), alpha-adrenergic agonists, calcium, magnesium, phosphorus, and thyroid hormone in the treatment of impaired cardiac contractility during critical illness.

A 45-year-old woman with a history of rheumatic mitral disease underwent valve replacement. After surgery, the patient became hemodynamically unstable. A transesophageal echocardiogram showed an underfilled left ventricle with a clot impinging on the lateral aspect of the left ventricle and a malfunctioning mitral valve prosthesis. After evacuation of the clot in the operating room, the mitral valve prosthesis began functioning normally. The prosthesis malfunction resulted from external cardiac compression. This dynamic device malfunction was replicated when the surgeon compressed the lateral aspect of the heart. To our knowledge, this dynamic form of leaflet dysfunction from external compression has not been described. This case highlights the importance of closely evaluating prosthetic valve function in the setting of hemodynamic deterioration.

To determine whether epinephrine might prove to be a cost-effective substitute for dobutamine, two 8-minute infusions of either epinephrine (10 and 30 ng/kg/min, n = 28) or dobutamine (2.5 and 5 micrograms/kg/min, n = 24) were administered to 52 patients recovering in the intensive care unit (ICU) after aortocoronary bypass (CABG) surgery. At the higher dose, both drugs significantly (P < .05) increased cardiac index (CI), epinephrine from 2.8 +/- 0.1 at baseline to 3.3 +/- 0.1 L/min/m2, and dobutamine from 3.2 +/- 0.1 at baseline to 4.1 +/- 0.2 L/min/m2. Epinephrine increased CI significantly less than dobutamine. Both drugs significantly increased stroke volume index (SVI), epinephrine from 32 +/- 1 at baseline to 36 +/- 1 mL/beat/m2, and dobutamine from 36 +/- 1 at baseline to 40 +/- 2 mL/beat/m2. At the higher dose, the effects of the two drugs on SVI were indistinguishable. On the other hand, while the higher dose of both drugs significantly increased heart rate (HR), epinephrine from 88 +/- 2 at baseline to 90 +/- 2 beats/min and dobutamine from 89 +/- 2 at baseline to 105 +/- 3 beats/min, the increase following the higher dose of dobutamine was significantly greater than that seen after epinephrine. Effects of the two drugs on mean arterial pressure, central venous pressure, pulmonary artery occlusion pressure, systemic vascular resistance, pulmonary vascular resistance, and left-ventricular stroke work did not significantly differ. Similar results were obtained in the subset of patients with baseline CI less than 3 L/min/m2 who more closely resembled patients who might acutely require inotropic drug administration.(ABSTRACT TRUNCATED AT 250 WORDS)

The subspecialty of interventional cardiology has made significant progress in the management of coronary artery disease over the past three decades with the development of percutaneous coronary transluminal angioplasty, atherectomy, and bare-metal and drug-eluting stents (DES). Bare-metal stents (BMS) maintain vessel lumen diameter by acting as a scaffold and prevent collapse incurred by angioplasty. However, these devices cause neointimal hyperplasia leading to in-stent restenosis and requiring reintervention in more than 20% of patients by 6 mo. DES (sirolimus and paclitaxel) prevent restenosis by inhibiting neointimal hyperplasia. However, DESs also delay endothelialization, causing the stents to remain thrombogenic for an extended, yet unknown, period of time. Late stent thrombosis is associated with a 45% mortality rate. Premature discontinuation of antiplatelet therapy, particularly clopidogrel, is the strongest predictor of stent thrombosis. Sixty percent of patients receive stents for off-label (unapproved) indications, which also increases the frequency of stent thrombosis. Clopidogrel and aspirin are the cornerstone of therapy in the prevention of stent thrombosis in both BMS and DES. Recommendations pertaining to the optimal duration of dual-antiplatelet therapy have been debated. Both the Food and Drug Administration and the American Heart Association/American College of Cardiologists, in association with other major societies, have made recommendations to extend the duration of dual-antiplatelet therapy in patients with DES to 1 yr. The 6-wk duration of dual-antiplatelet therapy in patients with BMS remains unchanged. All patients with coronary stents must remain on life-long aspirin monotherapy. Since the introduction of percutaneous transluminal coronary angioplasty for the treatment of coronary atherosclerosis, the practice of percutaneous coronary intervention has undergone a dramatic transformation from simple balloon dilation catheters to sophisticated mechanical endoprostheses. These advancements have impacted the practice of perioperative medicine. In this series of two articles, in Part I we will review the evolution of percutaneous coronary intervention and discuss the issues associated with percutaneous transluminal coronary angioplasty and coronary stenting; in Part II we will discuss perioperative issues and management strategies of coronary stents during noncardiac surgery.

UNLABELLED Pulmonary arterial catheters (PACs) are often used during and after coronary artery bypass grafting. We hypothesized that placement of a PAC would be faster in anesthetized patients. We further hypothesized that the presence or absence of a PAC during the induction of anesthesia would make no difference in hemodynamics, vasoactive drug use, or IV fluid administration during the induction. Patients (n = 200) undergoing elective coronary artery bypass grafting were assigned to PAC insertion either before or after the induction of anesthesia. Total time for PAC insertion, number of finder needle and venous catheter insertion attempts, incidence of carotid artery puncture, arrhythmias or ST segment changes, arterial blood gas analysis, hemodynamic variables, IV fluids, and vasoactive drugs required during and after the anesthetic induction were recorded. Thirty-two different physicians placed the PACs. PAC placement was faster (10 versus 12 min, P = 0.0003) and required fewer punctures with a finder needle (P = 0.0107) in anesthetized patients. There were no significant differences between groups in hemodynamic values or use of vasoactive or anesthetic drugs or IV fluids during the induction. There were also no significant differences between groups in the incidence of myocardial ischemia, arterial hypoxemia, or hypercarbia. Placement of a PAC before the induction of anesthesia consumes more time and fails to improve hemodynamic stability or lessen vasoactive drug use during the induction of anesthesia. IMPLICATIONS Insertion of pulmonary artery catheters (PACs) before the induction of anesthesia requires more needle sticks and takes longer than insertion after the induction of anesthesia; moreover, previous PAC insertion has no significant effect on hemodynamics or use of vasoactive drugs or IV fluid associated with the induction of anesthesia.

Objective: To determine whether patients receiving pegorgotein preoperatively would be less likely than patients receiving placebo to demonstrate postoperative cerebral or myocardial dysfunction and thus would be less likely to (1) demonstrate a decline in neuropsychologic testing after cardiopulmonary bypass, (2) receive inotropic drug support, or (3) demonstrate electrocardiographic signs of ischemia or infarction. Design: Prospective, randomized, blinded clinical trial. Setting: University teaching hospital and clinics. Participants: Sixty-seven patients with normal left ventricular function undergoing elective, primary coronary artery bypass surgery. Interventions: Six to 18 hours before aortic cross-clamping, patients received a single dose of placebo (n = 22); pegorgotein, 2,000 IU/kg intravenously (n = 23); or pegorgotein, 5,000 IU/kg intravenously (n = 22). Measurements and Main Results: Patients in the three groups were similar; the mean ages were 65, 66, and 67 years, and there were seven, eight, and seven women in the placebo; pegorgotein, 2,000 IU/kg; and pegorgotein, 5,000 IU/kg groups. Fifty-one of 67 patients demonstrated neuropsychologic deficit 5 to 7 days postoperatively (n = 17, 19, and 15 for placebo, 2,000 IU/kg, and 5,000 IU/kg; p = NS). Median duration of cardiopulmonary bypass was longer in patients with two or more deficits at 4 to 6 weeks than in those with fewer than two deficits (121 v 98 minutes; p = 0.04). No patient demonstrated a perioperative stroke. Twenty-seven patients required inotropic drug support after cardiopulmonary bypass (n = 8, 11, and 8 for placebo, 2,000 IU/kg, and 5,000 IU/kg; p = NS). Inotropic drug support was associated with history of angina (p = 0.01) and increasing weight (p = 0.03). Nine patients demonstrated early postoperative ischemia or infarction (n = 1, 7, and 1 for placebo, 2,000 IU/kg, and 5,000 IU/kg; p = 0.07). Conclusions: This study showed no positive influence of pegorgotein on the incidence of any of the findings and showed a trend toward an increased incidence of myocardial ischemia or infarction.

Objectives: To determine (1) if perioperative use of esmolol in major vascular surgery patients provides strict heart rate (HR) control, (2) what doses of esmolol are required to do this, and (3) does this control influence myocardial ischemia or result in adverse consequences. Design: Prospective study of 40 patients randomized to two groups: The HR was controlled to either less than 80 beats/min (group 80) or less than 110 beats/min (group 110) using esmolol. Patients were monitored continuously for electrocardiographic changes perioperatively. HR control began after induction of anesthesia and continued for 48 hours thereafter. Setting: Operating room and intensive care unit. Patients: Patients undergoing abdominal vascular surgery involving aortic cross-clamping. Interventions: Esmolol was titrated until the target HR was met. Measurements and Results: Only one patient demonstrated an adverse effect. The median infusion rates were 100 and 12.5 μg/kg/min for groups 80 and 110. Target HR was met less in group 80 than in group 110, primarily in the postoperative period. Ischemia patterns were not significantly different between groups. Conclusion: Using esmolol for HR control in the intraoperative period for abdominal vascular surgery patients is effective and safe. HR control was much less effective in the postoperative period, but esmolol is safe when used at recommended doses. Further study with a larger number of patients is necessary to determine whether strict HR control with esmolol affects the incidence of myocardial ischemia or infarction in this patient population.

p w v w e IGHT VENTRICULAR (RV) apical pacing frequently worsens ventricular dyssynchrony. Data suggest that RV pical pacing is associated with an increase in hospitalizations or heart failure (HF) and atrial fibrillation (AF).1 Cardiac esynchronization therapy (CRT) improves hemodynamic, unctional, and quality of life indices in patients with chronic F.2-5 After cardiopulmonary bypass (CPB), a number of paients may exhibit symptoms of heart failure with interventriclar and intraventricular dyssynchrony. Patients may require trioventricular (AV) pacing in the immediate post-CPB peiod. RV pacing may result in worsened septal dyssynchrony nd hemodynamic profiles. The authors report a case in which arly implementation of biventricular pacing (BiVP) in the ost-CPB period resulted in the resolution of septal dyskinesia nd an immediate improvement in hemodynamic function.

Left ventricular dysfunction is common after cardiac surgery and is often treated with positive inotropic drugs (PIDs).We hypothesized that the use of PIDs after cardiac valve surgery would have significant associations with the valvular pathophysiology and surgical procedure, and unlike the case for patients undergoing coronary artery surgery, would be unrelated to duration of cardiopulmonary bypass (CPB) or of aortic clamping. One hundred forty-nine consenting patients undergoing cardiac valve surgery were studied. Patients with hepatic or renal failure, or New York Heart Association class IV cardiac symptoms, were excluded. Patients were considered to have received PIDs if they received an infusion of amrinone, dobutamine, epinephrine, or dopamine (>or=to5 [micro sign]g [center dot] kg-1 [center dot] min-1). PIDs were received by 78 patients (52%). In a univariate model, older age, history of congestive heart failure, decreasing left ventricular ejection fraction, longer durations of CPB, and concurrent coronary artery surgery significantly increased the likelihood of PID support. There was also significant variation by anesthesiologist in the administration of PIDs. The specific diseased valve and valvular stenosis or insufficiency did not influence the likelihood of receiving PID support. In a multivariable model, age, history of congestive heart failure, decreasing left ventricular ejection fraction, and anesthesiologist were significantly associated with the likelihood of PID support, but duration of CPB and concurrent coronary artery surgery were not. In conclusion, patient age and ventricular function, as well as physician preferences, predicted the need for inotropic drug support; however, neither the specific valvular lesion, nor duration of CPB were strongly predictive in a multivariable model. Implications: We evaluated factors related to use of positive inotropic drugs after cardiac valve surgery. The likelihood of a patient receiving these drugs increases with advancing age and with more severe preoperative left ventricular dysfunction, but was not influenced by the specific diseased valve or the duration of cardiopulmonary bypass. (Anesth Analg 1998;86:461-7)

To determine if renal dose dopamine (3 microg/kg/min) alters the heart rate (HR) by itself, or if a dopamine infusion alters the HR response to bolus doses of the beta-adrenergic agonist isoproterenol in healthy human subjects.Prospective study.Clinical laboratory of a university-affiliated academic medical center.A total of 15 healthy nonpregnant women and men aged 21 to 44 years.Subjects were monitored continuously with bedside ECG, pulse oximetry, and ambulatory ECG recording to measure the maximal HR response to separate injections of 10, 20, and 30 ng/kg of isoproterenol, given before, during, and after the infusion of 3 microg/kg/min of dopamine.Dopamine in the absence of isoproterenol did not alter baseline HR significantly (62.7+/-2.2 beats/min without dopamine; 65.4+/-2.2 with dopamine; p=0.15). All three doses of isoproterenol increased HR significantly above baseline, both in the presence and absence of dopamine (p0.001). Dopamine infusion resulted in a higher HR following isoproterenol only for the 20-ng/kg dose. The incremental increases in HR, defined as the difference between peak HR following isoproterenol and baseline HR, were not increased during dopamine infusion for any of the doses of isoproterenol. Nausea was reported by 5 of the 15 subjects during the dopamine infusion.In healthy human subjects, infusion of 3 microg/kg/min of dopamine does not significantly increase the HR when combined with beta-adrenergic stimulation using isoproterenol, suggesting neither an additive nor antagonistic interaction between the two drugs. While our study did not demonstrate an increase in HR in healthy subjects, the risk of increasing the chronotropic response to beta-adrenergic inotropic medications with "renal dose" dopamine in critically ill patients needs to be investigated. The frequency of nausea during dopamine infusion also may influence consideration of using dopamine to augment splanchnic blood flow and renal function in conscious patients.

This study evaluates whether repeated postoperative visits by the anesthesiologist improve patient ability to recall the anesthesiologist's name and the patient's perception of and satisfaction with anesthesia services. In a randomized, prospective trial, 144 patients with an anticipated postoperative length of stay of at least three days were enrolled in three groups: Group A patients (n = 48) had one postoperative visit, Group B (n = 48) had two postoperative visits, and Group C (n = 48) had three postoperative visits. All postoperative visits were performed by the attending anesthesiologist on consecutive postoperative days. Patients were contacted two days after their last postoperative visit to complete a study questionnaire. Patients were able to recall the anesthesiologist's name significantly less frequently than the surgeon's name, and there was no difference in name recall among groups. Recall was not affected by patient age, sex, or ASA physical status; the mode of contact (telephone versus personal visit); the anesthesiologist's gender; the presence of preoperative medication; or the identity of the preoperative evaluator. Patients could identify the anesthesiologist's gender approximately 85% of the time, regardless of group, and were more likely to identify female anesthesiologists (P = 0.026, odds ratio 3.3). Patient evaluation of hospital, surgical, and anesthesia care was favorable in all groups and did not vary with group. Increasing the number of postoperative visits does not improve patient name recognition of the anesthesiologist or increase patient satisfaction with or perception of anesthesia services.

Patients with anterior mediastinal masses are at increased risk for perioperative complications. Our case demonstrates that airway collapse and inability to ventilate may occur in the asymptomatic adult despite spontaneous ventilation with inhaled anesthesia and an endotracheal tube. Given the sudden and profound presentation of cardiopulmonary collapse, rigid bronchoscopy should be immediately available to facilitate life-saving ventilation. Though repositioning the pediatric patient lateral or prone has been reported to reestablish airway patency, this maneuver may be of limited benefit in the adult population because of a more ossified and developed chest wall. Lastly, if a high-risk patient requires a general anesthetic, strong consideration should be given to preinduction placement of femoral cardiopulmonary bypass cannulae and the availability to immediately initiate cardiopulmonary bypass.

Objective Dopexamine hydrochloride is a novel synthetic adrenergic agonist that combines the renal effects of dopamine with the hemodynamic effects of dobutatmine. Our study is designed to compare the hemodynamic, diuretic, and natriuretic effects of dopexamine and dobutamine in patients with reduced cardiac index following heart surgery. Design Prospectively randomized, blinded study. Setting Operating room and intensive care unit of a large, urban, academic medical center. Patients Twenty-eight patients undergoing elective coronary artery bypass grafting (CABG) with preoperative ejection fraction of at least 40 percent gave informed consent. The study group consisted of the ten patients who had a cardiac index ≤2.5 L/min/m 2 (while receiving no inotropic medication) immediately after separation from cardiopulmonary bypass. Interventions and measurements Study patients were randomly given a starting dose of either 5μg/kg/min of dobutamine (n=5) or 2 μg/kg/min of dopexamine (n=5). During the initial 30 min following separation from bypass, dosages were titrated incrementally to maintain cardiac index ≥3.0/L/min/m 2 . Further titrations of the drug were done only if cardiac index fell below 3.0 L/min/m 2 or if sustained tachycardia occurred during the 24-h study period. Data were collected at 5- and 10-min intervals for the first 30 min after separation from bypass, hourly for the next 8 h, then every 2 h for the remainder of the study period. Results Both drugs increased cardiac index by more than 50 percent over baseline (dobutamine 2.2 ± 0.1 to 3.5 ± 0.2 [p 2 ). The mean dose required to maintain cardiac index ≥3.0L/min/m 2 was 1.5 μg/kg/min for dopexamine and 3.5 μg/kg/min for dobutamine. There were no significant differences in either urinary output or net sodium excretion in the dopexamine group compared with the dobutamine group, and tachycardia (heart rate >120 beats/min) was more common in the dopexamine group. Conclusions Our study demonstrates that dopexamine produces hemodynamic, diuretic, and natriuretic effects similar to dobutamine in patients with reduced cardiac index following CABG.