Michael G. Licina

A Phase III, Double-blind, Placebo-controlled, Multicenter Study on the Efficacy of Recombinant Human Antithrombin in Heparin-resistant Patients Scheduled to Undergo Cardiac Surgery Necessitating Cardiopulmonary Bypass

Background:The study evaluated the efficacy of recombinant human antithrombin (rhAT) for restoring heparin responsiveness in heparin resistant patients undergoing cardiac surgery. Methods:This was a multicenter, randomized, double-blind, placebo-controlled study in heparin-resistant patients undergoing cardiac surgery with cardiopulmonary bypass. Heparin resistance was diagnosed when the activated clotting time was less than 480 s after 400 U/kg heparin. Fifty-four heparin-resistant patients were randomized. One cohort received 75 U/kg rhAT, and the other received normal saline. If the activated clotting time remained less than 480 s, this was considered treatment failure, and 2 units fresh frozen plasma was transfused. Patients were monitored for adverse events. Results:Only 19% of patients in the rhAT group received fresh frozen plasma, compared with 81% of patients in the placebo group (P < 0.001). During their hospitalization, 48% of patients in the rhAT group received fresh frozen plasma, compared with 85% of patients in the placebo group (P = 0.009). Patients in the placebo group required higher heparin doses (P < 0.005) for anticoagulation. There was no increase in serious adverse events associated with rhAT. There was increased blood loss 12 h postoperatively (P = 0.05) with a trend toward increased 24-h bleeding in the rhAT group (P = 0.06). There was no difference between the groups in blood and platelet transfusions. Conclusion:Treatment with 75 U/kg rhAT is effective in restoring heparin responsiveness and promoting therapeutic anticoagulation in the majority of heparin-resistant patients. Treating heparin-resistant patients with rhAT may decrease the requirement for heparin and fresh frozen plasma.

Intraoperative echocardiography is indicated in high-risk coronary artery bypass grafting

BACKGROUND Intraoperative echocardiography is a valuable monitoring and diagnostic technology used in cardiac surgery. This reports our clinical study of the usefulness of intraoperative echocardiography to both surgeons and anesthesiologists for high-risk coronary artery bypass grafting. METHODS From March to November 1995, 82 consecutive high-risk patients undergoing coronary artery bypass grafting were studied in a four-stage protocol to determine the efficacy of intraoperative echocardiography in management planning. Alterations in surgical and anesthetic/hemodynamic management initiated by intraoperative echocardiography findings were documented in addition to perioperative morbidity and mortality. RESULTS Intraoperative echocardiography initiated at least one major surgical management alteration in 27 patients (33%) and at least one major anesthetic/hemodynamic change in 42 (51%). Mortality and the rate of myocardial infarction in this consecutive high-risk study population using intraoperative echocardiography and in a similar group of patients without the use of intraoperative echocardiography was 1.2% versus 3.8% (not significant) and 1.2% versus 3.5% (not significant), respectively. CONCLUSIONS We conclude that when all of the isolated diagnostic and monitoring applications of perioperative echocardiography are routinely and systematically performed together, it is a safe and viable tool that significantly affects the decision-making process in the intraoperative care of high-risk patients undergoing primary isolated coronary artery bypass grafting and may contribute to the optimal care of these patients.

The effect of ketamine on human somatosensory evoked potentials and its modification by nitrous oxide

The effect of ketamine alone and in combination with N2O (70% inspired) on median nerve somatosensory evoked potentials (SSEPs) was investigated in 16 neurologically normal patients undergoing elective abdominopelvic procedures. The anesthetic regimen consisted of ketamine (2 mg/kg iv bolus followed by continuous infusion at a rate of 30 micrograms.kg-1.min-1) [corrected], neuromuscular blockade (atracurium), and mechanical ventilation with 100% oxygen. SSEP recordings were obtained immediately preinduction and at 2, 5, 10, 15, 20, and 30 min postinduction. Thereafter, N2O was added with surgical incision and maintained for 15 min. At 5-min intervals, SSEP recordings were again taken during and after N2O. With minor exceptions, mean cortical and noncortical latencies as well as noncortical-evoked potential amplitude were unaffected by either ketamine or N2O. Ketamine induction increased cortical amplitude significantly with maximal increases occurring within 2-10 min. For example, at 5-min postinduction, mean N1-P1 amplitude increased from 2.58 +/- 1.05 (baseline) to 2.98 +/- 1.20 microV and P1-N2 amplitude increased from 2.12 +/- 1.50 (baseline) to 3.99 +/- 1.76 microV. Throughout the 30-min period after ketamine induction, mean P1-N2 amplitude increased generally by more (57-88%) than did mean N1-P1 amplitude (6-16%). N2O added to the background ketamine anesthetic produced a rapid and consistent reduction in both N1-P1 and P1-N2 amplitude. Thus, at 1 min after N2O, mean N1-P1 amplitude decreased from 2.74 +/- 1.11 to 1.64 +/- 0.63 microV, while P1-N2 amplitude decreased from 3.32 +/- 1.52 to 1.84 +/- 0.87 microV.(ABSTRACT TRUNCATED AT 250 WORDS)

Educational program for intraoperative transesophageal echocardiography

A lthough both disciplines have cooperated for many years, cardiovascular anesthesiology and echocardiography have recently grown and merged in part. Intraoperative echocardiography has demonstrated its usefulness in many aspects of cardiovascular surgery, including valvular repair and replacement, myocardial function, aortic aneurysm repair, congenital heart disease, pericardial disease, complications of surgery, endocarditis, myocardial ischemia, and many others. Given the enlarging scope of cardiovascular surgery, echocardiography can address the compelling need for precise and accurate intraoperative diagnostic and monitoring capabilities. With the rapid development and clinical application of this technology, little attention has been focused on the necessary skills, training, and means of confirming competency for physicians performing intraoperative echocardiography. This article will not address all the questions surrounding this subject, but will explore some of the relevant issues regarding the training of physicians in intraoperative echocardiography and describe the training program developed for anesthesiologists at the Cleveland Clinic. We present our program in the hope of stimulating further discussion and research. The ultimate objective in developing an organized training program in intraoperative echocardiography is to enhance patient care at our institution through the proficient use of echocardiography in the operating arena by physicians from varying specialties and practice backgrounds.

Cardiac surgery in a patient taking monoamine oxidase inhibitors: an adverse fentanyl reaction.

M onoamine oxidase inhibitors (MAOIs), are used to treat endogenous psychotic depression. The MAOIs do not inhibit catecholamine synthesis; rather they block the oxidative deamination of endogenous catecholamines into inactive vanillylmandilic acid. This block of MA0 produces an accumulation of endogenous catecholamines in adrenergically active tissues, such as the brain, which is thought to be responsible for alleviation of depression. Major concerns with the clinical use of MAOIs are related to 1) the risk of dietary intake of tyramine, an indirect sympathomimetic, which can trigger a release of accumulated catecholamines, 2) drug interactions, specifically with opioids, which have been reputed to cause a syndrome of hyperpyrexia, hypertension, tachycardia, and coma (1 1, and 3) hepatotoxicity, which does not seem to be related to dose or duration of treatment. When patients on MAOIs require urgent surgery or the relief of severe pain, there is concern about these potentially fatal drug interactions. Despite such potential interactions and risks, adverse outcomes are rarely reported in clinical practice. However, there are 12 case reports in the world literature implicating the combination of meperidine and MAOIs as potentially fatal, this being related to an inhibition of 5-hydroxytryptamine (5-HT) uptake by both the opioid and MA01 in the brain leading to increased levels of 5-HT at the synaptic cleft and consequent adverse reactions including hyperpyrexia, hypertension, hypotension, tachycardia, or convulsions (2-12). There has been only one case described of an adverse morphine/MAOI interaction (13). This involved a patient who became hypotensive and unconscious after receiving morphine (6 mg intravenously [IV]), but the etiology was uncertain. Five cases have been reported of fentanyl being administered to patients on chronic MA01 therapy (14-16); four of these cases did not have an adverse outcome

Systemic lidocaine and human somatosensoryevoked potentials during sufentanil-isoflurane anaesthesia

The effect of systemically administered lidocaine on somatosensory evoked potentials (SSEPs) during general anaesthesia has not been widely reported. Knowledge of the influence of anaesthetic agents on evoked potentials assists in interpreting evoked potential waveforms. Accordingly, we studied the behaviour of cortical and subcortical (recorded at the second cervical vertebra) SSEPs after administration of intravenous lidocaine (3 mg · kg−1 bolus followed by infusion at 4 mg · kg−1 · hr−1) during a sufentanil-based anaesthetic regimen in 16 patients undergoing abdominal or orthopaedic surgery. When compared to awake baseline recordings, the sufentanil-nitrous oxide, low-dose isoflurane anaesthetic depressed N1 amplitude by approximately 40% and prolonged latency by 10%. Fifteen minutes after establishment of this anaesthetic, the amplitude and latency of N1 were 1.13 ± 0.56 μV and 19.81 ± 1.63 msec, respectively. Within five minutes of adding lidocaine, amplitude decreased further to 0.84 ± 0.39 μV (P = 0.001), while latency was extended to 20.44 ± 1.48 msec (P = 0.01). Lidocaine did not affect cervical amplitude and prolonged latency only minimally. Despite the observed effects on amplitude and latency, SSEP waveforms were preserved and interpretable. Plasma lidocaine levels obtained at 5, 20, and 40 minutes after lidocaine were 5.17 ± 1.33, 3.76 ± 1.14, and 3.66 ± 0.9 μg · dl−1, respectively. Our results indicate that systemically administered lidocaine at therapeutic plasma levels acts synergistically with a sufentanilbased anaesthetic to depress the amplitude and prolong the latency of SSEPs.RésuméIl existe peu de publications sur l’effet de la lidocaine administrée par voie systemique sur les potentiels évoqués somatosensitifs (SSEP) pendant l’anesthésie générate. La connaissance des effets des agents anesthésiques sur les potentiels évoqués aide à l’interprétation des ondes de potentiels évoqués. Nous avons étudié l’effet de bl’administration de lidocaine par voie intraveineuse (bolus de 3 mg · kg−1 suivi d’une perfusion de 4 mg · kg−1 · h−1) sur les SSEP corticaux et sous-corticaux (enregistre au niveau de la deuxieme vertebre cervical) chez 16 patients anesthésiés avec une technique à base de sufentanil pendant une chirurgie abdominale ou orthopédique. Comparativement aux enregistrements de base en etat d’éveil, l’anesthésie à l’aide de sufentanil-protoxyde d’azote et faible dose d’isoflurane déprimait l’amplitude N1 d’environ 40% et prolongeait la latence de 10%. Après 15 minutes d’anesthésie, l’amplitude et la latence de Nl étaient de 1,13 ± 0,56 μV et 19,81 ± 1,63 msec respectivement. Cinq minutes après l’addition de lidocaine, l’amplitude a diminue a 0,84 ± 0,39 μV (P < 0,001) tandis que la latence a augmente a 20,44 ± 1,48 msec (P < 0,01). La lidocaine n ’a pas affecté l’amplitude cervical et a très peu prolonge la latence. Malgré les effets observés sur l’amplitude et la latence, les ondes SSEP étaient préservées et interprétables. Les niveaux plasmatiques de lidocaïne à 5, 20 et 40 minutes après l’injection étaient de 5,17 ± 1,33, 3,76 ± 1,14 et 3,66 ± 0,9 μg · dr−1 respectivement. Nos résultats démontrent que la lidocaine administree par voie systémique à des niveaux plasmatiques thérapeutiques agit en synergie avec une technique anesthésique à base de sufentanil en provoquant une dépression de l’amplitude et une prolongation de la latence des SSEP.

The Effect of Intrathecal Morphine on Somatosensory Evoked Potentials in Awake Humans

Although the effect of systemic opioids on somatosensory evoked potentials has been well described, little is known about the interaction between intrathecally administered opioid analgesics and somatosensory evoked potentials. Accordingly, the influence of intrathecally administered morphine on posterior tibial nerve somatosensory cortical evoked potentials (PTSCEPs) was investigated in 22 unpremedicated, awake, neurologically normal patients scheduled to undergo elective abdominal or pelvic procedures. Patients were randomly assigned to receive either preservation-free intrathecal morphine sulfate (ITMS) or placebo. After baseline PTSCEP, heart rate and, mean blood pressure were recorded, ITMS (15 micrograms.kg-1) was injected via standard dural puncture with the patient in the lateral position. PTSCEPs, heart rate, and mean blood pressure were recorded again at 5, 10, 20, 30, 60, 90, and 120 min. Control patients were treated identically (including position, sterile preparation, and subcutaneous tissue infiltration with local anesthetic), except for lumbar puncture, and were unaware of their randomization. Before administration of ITMS, PTSCEP P1, N1, P2, N2, and P3 latencies were 39.4 +/- 3.2, 47.6 +/- 3.9, 59.2 +/- 3.2, 70.4 +/- 3.7, and 84.6 +/- 5.5 ms, (mean +/- standard deviation), respectively. The corresponding P1-N1, N1-P2, and P2-N2 amplitudes were 2.4 +/- 1.1, 2.4 +/- 1.1, and 2.3 +/- 0.9 microV, respectively. There were no significant changes over time between the control and ITMS groups. PTSCEPs resulting from left-sided stimulation were not different from those elicited by right-sided stimulation. All ITMS patients had intense postoperative analgesia for at least 24 h. It is concluded that ITMS does not affect PTSCEP waveforms in the 35-90 ms latency range during the awake state.(ABSTRACT TRUNCATED AT 250 WORDS)

Perioperative management and outcome of patients having cardiac surgery combined with abdominal aortic aneurysm resection

Patients with abdominal aortic aneurysms (AAA) have a high incidence of associated cardiac disease. If a patient presents with both severe coronary artery disease and a large AAA, a staged procedure of cardiac surgery (CS) followed by AAA resection may present too great a risk of aneurysm rupture and death. A combined procedure may be recommended in this circumstance; however, the literature contains only individual successful case reports of such a procedure. A series of 10 patients who underwent CS and AAA repair to define the risks and outcome of this complex patient population is presented. Methods used included a retrospective analysis of hospital chart data from patients undergoing combined CS and AAA resection from 1980 to the present at this institution. The data analyzed included age, sex, chief complaint, past medical history, indications for surgery, abdominal aneurysm size, coronary anatomy, valvular pathology, preoperative left ventricular function, anesthetic agent and dose, order of surgery, prebypass complications, intraoperative complications, cardiopulmonary bypass time, aortic cross-clamp time, abdominal aortic cross-clamp time, blood product use, and postoperative complications. Seven of the 10 patients had a successful outcome (S group), whereas 3 of the 10 patients died postoperatively (D group). The staged procedure of first performing CS and then the AAA resection has a combined operative mortality of 4%. When the nature of both lesions is severe and a combined procedure is necessary, there is an associated in-hospital mortality of approximately 30% at this institution. The S group patients had an unremarkable postoperative course with a relatively short hospital stay when compared to the staged procedure.

ORGANIZATION OF A COMPREHENSIVE ANESTHESIOLOGY ORAL PRACTICE EXAMINATION PROGRAM: Planning, Structure, Startup, Administration, Growth and Evaluation.

BACKGROUND Oral practice examinations (OPEs) are used in many anesthesiology programs to familiarize residents with the format of the oral qualifying examination given by the American Board of Anesthesiology (ABA). The purpose of this communication is to describe the planning, structure, startup, administration, growth and evaluation of a comprehensive oral examination program at a sizeable residency program in the Midwest. METHODS AND RESULTS A committee of three experienced faculty was formed to plan the effort. Planning involved consideration of format and frequency of administration, timing for best resident and faculty availability, communication, forms design, clerical support, record keeping and quality monitoring. To accommodate resident rotation and faculty work schedules, a semiannual administration schedule on 3-4 consecutive Mondays was chosen. The mock oral format was deliberately constructed to resemble that used by the ABA so as to enhance resident familiarity and comfort with ABA style oral exams. Continued quality improvement tools put in place consisted of regular examiner and examinee inservice sessions, communication and feedback from ABA associate examiners to faculty examiners as well as review of examinee exit questionnaires. A set of OPE databases were constructed so as to facilitate quality monitoring and educational research efforts. Continued administration of the OPE program required ongoing construction of a pool of guided case-oriented questions, selection of appropriate questions based on examinee training exposure, advance publication of the exam calendar and scheduling of recurring examiner and examinee activities. Significant issues which required action by the governing committee were exam timing, avoidance of conflict with clinical demands, use of OPE results, and procurement of training resources. Despite initial skepticism, the OPE program was begun successfully and grew substantially from 56 exams in the first year to 120 exams by year three. The OPE was perceived positively by the majority of residents. 90.2% of exit questionnaires acknowledged specific learning about oral exam technique, while only 0.3% indicated lack of meaningful information exchange at OPE sessions. Fewer than 10% of responses indicated misleading questions or badgering by examiners. Although anxiety remained constant over time, resident preparedness increased with repeat OPE exposure. SUMMARY A comprehensive mock oral examination of substantial scope was successfully planned, initiated, and developed at our anesthesiology resident training program. It is well accepted by residents and faculty. Its inception was associated with an increase in resident preparedness. Now in its tenth year of existence it continues to be an asset and essential component of our training program.

GlideScope videolaryngoscope-assisted retrieval of an intratracheal foreign body.

Postintubation tracheal stenosis presents major challenges to the anesthesiologist, especially in situations where the airway is shared with the surgeon. The airway management of a patient with severe postintubation subglottic stenosis, who developed complete airway obstruction during attempted tracheal dilatation, is presented.