[Clinical experience in thoracoscopic left internal mammary artery harvesting with voice activated robotic assistance].

Between September 1998 to February 2000, 45 consecutive patients underwent robotic-assisted, video-enhanced coronary artery bypass grafting. All IMA's were harvested using the voice-activated robotic assistant (AESOP 3000, Computer Motion Inc, Santa Barbara, CA) and the Harmonic scalpel (Ethicon Endo-Surgery, Cincinnati, OH). Left IMA's were successfully harvested in all patients. Harvested IMA's were anastomosed to LAD's under direct vision through limited left anterior thoracotomy. The IMA harvest time was 57.8 +/- 23.2 min, intraoperative graft flow was 34.3 +/- 20.5 ml/min, postoperative hospital stay was 3.9 +/- 1.5 days. The early postoperative angiogram showed that all grafts were patent. There was no mortality, no significant morbidity. The robotic assisted, video enhanced CABG provides safe and complete LIMA dissection with minimal manipulation and assures sufficient LITA length for tension free anastomosis.

RAVECAB: improving outcome in off-pump minimal access surgery with robotic assistance and video enhancement.

OBJECTIVE: To determine the efficacy of using the harmonic scalpel and robotic assistance to facilitate thoracoscopic harvest of the internal thoracic artery (ITA). DESIGN: A case series. SETTING: London Health Sciences Centre, University of Western Ontario, London, Ont. PATIENTS AND METHODS: Fifteen consecutive patients requiring harvest of the ITA for coronary artery bypass grafting. INTERVENTION: Robot-assisted, video-enhanced coronary artery bypass (RAVECAB) through limited-access incisions, using the harmonic scalpel and a voice-activated robotic assistant. MAIN OUTCOME MEASURES: Ease and duration of the harvesting technique, complications of the procedure, graft flow and patency, and duration of postoperative hospitalization. RESULTS: RAVECAB facilitated thoracoscopic dissection of the ITA with the harmonic scalpel in all cases. There were no conversions to a standard approach and no reoperations for bleeding. The mean (and standard deviation) ITA harvest time was 64.1 (22.9) minutes (range from 40 to 118 minutes). Robotic voice command capture rate was greater than 95%. Mean (and SD) intraoperative graft flows were 33.1 (26.8) mL/min (range from 14 to 126 mL/min). There was 100% graft patency on postoperative angiography. There were no deaths, perioperaive myocardial infarction or arrhythmias. Mean (and SD) postoperative hospitalization was 3.3 (0.8) days. CONCLUSIONS: RAVECAB is a demanding procedure that addresses many of the disadvantages of the "conventional" minimally invasive coronary artery bypass. It allows complete pedicle dissection with minimal ITA manipulation and assures sufficient conduit length and a tension-free coronary artery anastomosis. All anastomoses were performed under direct vision through a 5- to 8-cm inferior mammary incision.

Robot-assisted computer enhanced closed-chest coronary surgery: preliminary experience using a Harmonic Scalpel and ZEUS.

BACKGROUND: Successful endoscopic harvesting of arterial conduits is critical to the performance of totally endoscopic bypass grafting. Recent success with computer-enhanced robotic systems in the performance of endoscopic single vessel coronary artery bypass (ENDOCAB) has paved the way for developing techniques for multivessel ENDOCAB. The Harmonic Scalpel (Ethicon Endo-Surgery, Cincinnati, OH) has previously demonstrated versatility and efficacy in manual endoscopic internal thoracic artery (ITA) harvesting. This study was undertaken to determine the feasibility of adapting this technology to a robotic telemanipulation system and its safety and efficacy in telerobotic ITA harvesting. METHODS: The Harmonic Scalpel was adapted to the ZEUS robotic surgical system (Computer Motion, Goleta, CA) and used to harvest the ITA in 19 patients undergoing multivessel off-pump coronary artery bypass (OPCAB) surgery. With the left lung collapsed, the ITA was harvested in all patients with CO2 insufflation through three 5 mm ports in the left chest. Postoperative angiography and transthoracic Doppler studies were performed in all patients. RESULTS: There were no ITA injuries and patients tolerated insufflation without hemodynamic compromise. Side branches were controlled easily without bleeding. Average ITA harvest time was 65 +/- 21 minutes. All vessels were patent after harvesting and demonstrated no angiographic evidence of injury. CONCLUSIONS: This paper demonstrates a technique by which the Harmonic Scalpel can be readily adapted to the ZEUS robotic telemanipulation system. Using this system, ITA's can be safely harvested totally endoscopically within a reasonable time frame for patients undergoing ENDOCAB.

A risk-benefit assessment of aprotinin in cardiac surgical procedures.

Aprotinin, a naturally occurring serine protease inhibitor, has found widespread application during cardiac surgical procedures as a consequence of its ability to decrease blood loss and transfusion requirements. While its efficacy in a variety of clinical situations associated with increased risk of blood loss has been well established, at the same time, various complications including anaphylaxis, renal insufficiency, graft closure and arterial thromboses have been reported in association with aprotinin administration. In order to more fully evaluate the risks and benefits associated with aprotinin usage, this review first of all examines the hazards associated with transfusion of blood and blood products. Consideration is then given to various alternatives to allogeneic transfusion, including autologous predonation, acute normovolemic hemodilution, perioperative cell salvage and intraoperative plasma sequestration. A critique of other available pharmacological therapies, specifically desmopressin, aminocaproic acid and tranexamic acid, reviewing their modes of action, efficacy and associated complications, is then made. The role of aprotinin in cardiac surgery is then discussed and its pharmacology, including consideration of its antifibrinolytic, platelet preserving and anti-inflammatory effects is reviewed. Finally, an analysis of potential complications associated with aprotinin administration is undertaken. Issues involving its influence on specific measures of anticoagulation, namely partial thromboplastin time and activated clotting time, and issues relating to graft patency, hypothermic circulatory arrest, renal function, and allergic reactions are analysed and interpreted. In summary, this review concludes that most of the risks associated with aprotinin administration primarily involve inadequate anticoagulation and those of developing an allergic reaction, particularly upon aproptinin re-exposure. The benefits of aproptinin to decrease blood loss and transfusion requirements are confirmed, and there is evidence pointing to the intriguing possibility of a potential salutary effect on perioperative central nervous system complications.

Propofol has no direct effect on sinoatrial node function or on normal atrioventricular and accessory pathway conduction in Wolff-Parkinson-White syndrome during alfentanil/midazolam anesthesia.

BACKGROUND: Propofol has been implicated as causing intraoperative bradyarrhythmias. Furthermore, the effects of propofol on the electrophysiologic properties of the sinoatrial (SA) node and on normal atrioventricular (AV) and accessory pathways in patients with Wolff-Parkinson-White syndrome are unknown. Therefore, this study examined the effects of propofol on the cardiac electrophysiologic properties in humans to determine whether propofol promotes bradyarrhythmias and its suitability as an anesthetic agent in patients undergoing ablative procedures. METHODS: Twelve patients with Wolff-Parkinson-White syndrome undergoing radiofrequency catheter ablation were studied. Anesthesia was induced with alfentanil (50 micrograms/kg), midazolam (0.15 mg/kg), and vecuronium (20 mg) and maintained with alfentanil (2 micrograms.kg-1.min-1) and midazolam (1-2 mg, every 15 min, as needed). A electrophysiologic study was performed consisting of measurement of the effective refractory period of the right atrium, AV node, and accessory pathway and the shortest cycle length of the AV node and accessory pathway during antegrade stimulation plus the effective refractory period of the right ventricle and accessory pathway and the shortest cycle length of the accessory pathway during retrograde stimulation. Determinants of SA node function including sinus node recovery time, corrected sinus node recovery time, and SA conduction time; intraatrial conduction time and atrial-His interval also were measured. Reciprocating tachycardia was induced by rapid right atrial or ventricular pacing, and the cycle length and atrial-His, His-ventricular, and ventriculoatrial intervals were measured. Alfentanil/midazolam was then discontinued. Propofol was administered (bolus 2 mg/kg + 120 micrograms.kg-1.min-1), and the electrophysiologic measurements were repeated. RESULTS: Propofol caused a statistically significant but clinically unimportant prolongation of the right atrial refractory period. The effective refractory periods of the AV node, right ventricle, and accessory pathway, as well as the shortest cycle length, were not affected. Parameters of SA node function and intraatrial conduction also were not affected. Sustained reciprocating tachycardia was inducible in 8 of 12 patients, and propofol had no effect on its electrophysiologic properties. All accessory pathways were successfully identified and ablated. CONCLUSIONS: Propofol has no clinically significant effect on the electrophysiologic expression of the accessory pathway and the refractoriness of the normal AV conduction system. In addition, propofol has no direct effect on SA node activity or intraatrial conduction; therefore, it does not directly induce bradyarrhythmias. It is thus a suitable agent for use in patients undergoing ablative procedures who require either a neuroleptic or general anesthetic.

The electrophysiologic effects of volatile anesthetics and sufentanil on the normal atrioventricular conduction system and accessory pathways in Wolff-Parkinson-White syndrome.

BACKGROUND: The effects of volatile agents and sufentanil anesthesia on the electrophysiologic properties of the accessory pathway and on the incidence of intraoperative tachyarrhythmias in patients with Wolff-Parkinson-White syndrome are unknown. Therefore, we studied these agents for their use in patients undergoing ablative procedures or requiring a general anesthetic for other surgeries. METHODS: Twenty-one patients with Wolff-Parkinson-White syndrome undergoing surgical ablation were anesthetized with sufentanil (20 micrograms/kg), lorazepam (0.06 mg/kg), and vecuronium (20 mg). After sternotomy, the electrophysiologic study during antegrade stimulation consisted of the effective refractory period of the right atrium, atrioventricular node, and accessory pathway; the shortest cycle length of the atrioventricular node and accessory pathway; and the coupling interval. During retrograde stimulation, the effective refractory period of the right ventricle and accessory pathway and the shortest cycle length of the accessory pathway were measured and compared to preoperative electrophysiologic values. Patients then were randomized to receive 1 MAC of halothane, isoflurane, or enflurane, and the electrophysiologic study was repeated. RESULTS: Sufentanil-lorazepam caused mild prolongation (P < 0.05) of the effective refractory period of the accessory pathway and the shortest cycle length of the atrioventricular node. Enflurane and isoflurane significantly prolonged all parameters related to refractoriness during antegrade conduction, with enflurane having the largest effect. During retrograde conduction, isoflurane prolonged the effective refractory period of the right ventricle and accessory pathway and the shortest cycle length of the accessory pathway, whereas enflurane prolonged only the accessory pathway effective refractory period and shortest cycle length. Halothane had the least effect on refractoriness, causing significant prolongation of the atrioventricular node effective refractory period and the shortest cycle length of the accessory pathway only during antegrade conduction. The coupling interval, a measure of the period of vulnerability to supraventricular tachycardia, was prolonged only by halothane and isoflurane. Supraventricular tachycardia was still obtainable in all patients. CONCLUSIONS: Sufentanil-lorazepam has no clinically significant effect on the electrophysiologic expression of the accessory pathway. Of the volatile agents, enflurane most, isoflurane next, and halothane least increased refractoriness within the accessory and atrioventricular pathways. Therefore, administration of these volatile agents during ablative procedures may confound interpretation of postablative studies used to determine the success of ablation treatment. Conversely, in patients with preexcitation syndrome requiring general anesthesia for nonablative procedures, volatile agents may reduce the incidence of perioperative tachyarrhythmias because of their effects on refractoriness. Enflurane would be the agent of choice because it increases refractoriness the most without prolonging the coupling interval.

Alfentanil-midazolam anaesthesia has no electrophysiological effects upon the normal conduction system or accessory pathways in patients with Wolff-Parkinson-White syndrome.

The effects of alfentanil-midazolam anaesthesia upon the electrophysiologic (EP) properties of normal atrioventricular (A-V) and accessory pathway (AP) conduction were studied in eight patients with Wolff-Parkinson-White syndrome during accessory pathway surgical ablation. The presence of an AP was confirmed by preoperative EP studies. Anaesthesia was induced with alfentanil (50 micrograms.kg-1) and midazolam (0.15 mg.kg-1) and maintained with an alfentanil infusion (2 micrograms.kg-1.min-1) and intermittent boluses of midazolam (1-2 mg q 15 min, PRN). Following sternotomy, a baseline EP study was performed which consisted of effective refractory period (ERP) and shortest cycle length (SCC) measurement during antegrade conduction in the AV and AP, as well as during retrograde conduction in the AP. Comparison with preoperative EP studies indicated that the administration of alfentanil-midazolam anaesthesia had no effect upon conduction or ERP in either pathway. Haemodynamic stability occurred throughout the surgical procedure with no tachyarrhythmias. We conclude that a combination of alfentanil-midazolam is suitable for general anaesthesia in patients undergoing ablative procedures for accessory pathways.