Endoscopic computer-enhanced beating heart coronary artery bypass grafting.

BACKGROUND: Telemanipulation systems have enabled coronary revascularization on the arrested heart. The purpose of this study was to develop a technique for computer-enhanced endoscopic coronary artery bypass grafting on the beating heart. METHODS: The operation was performed using the daVinci telemanipulation system. Through three ports, the left internal thoracic artery was harvested in 10 mongrel dogs (30 to 35 kg) using single right-lung ventilation and CO2 insufflation. Through a fourth port an articulating stabilizer, manipulated from a second surgical console, was inserted to stabilize the heart. The left anterior descending artery was snared using silicone elastomer slings anchored in the stabilizer cleats and the graft to coronary artery anastomosis was performed. RESULTS: In 7 of 10 dogs, total endoscopic beating heart bypass grafting, cardiac stabilization, arteriotomy, and arterial anastomosis were performed using computer-enhanced technology. Endoscopic stabilization and temporary left anterior descending artery occlusion were well tolerated. All grafts were patent although minor strictures were found in 2. In 3 dogs, the procedure could not be completed (1 ventricular arrhythmia, 1 left atrial laceration, and 1 right ventricular outflow tract compression). CONCLUSIONS: Endoscopic beating heart coronary artery bypass grafting is possible in a canine model using a computer-enhanced instrumentation system and articulating stabilization.

Transabdominal endoscopic computer-enhanced coronary artery bypass grafting.

BACKGROUND: Due to limited range of motion, endoscopic multivessel revascularization is difficult through a thoracic approach. METHODS: A computer-enhanced surgical telemanipulation system was used to perform transabdominal endoscopic grafting (TCAB) in an experimental cadaver model. After incising the membranous portion of the diaphragm, pericardium, and pleura, dissection of the left (n = 10) and right internal thoracic arteries (n = 5) was performed. Coronary anastomoses were performed remotely and unassisted. In an animal model the hemodynamic consequences of the approach were assessed. RESULTS: In all cadavers TCAB was achieved through three abdominal ports. Time for internal thoracic arteries harvest was 48+/-13 minutes (left) and 39+/-10 minutes (right). Intimal dissection was found in one graft. Time for anastomosis was 23+/-9 minutes and 27+/-10 minutes for the left anterior descending (n = 10) and right coronary artery (n = 5), respectively. All anastomoses were patent. Opening the diaphragm in living animals led to a decrease of systolic blood pressure by 30+/16 mm Hg, but resolved with appropriate treatment. CONCLUSIONS: TCAB is possible in cadavers using computer-enhanced telemanipulation technology. The transabdominal approach is a promising access for less invasive cardiac surgery.

Ligand efficacy and potency at recombinant alpha2 adrenergic receptors: agonist-mediated [35S]GTPgammaS binding.

Alpha-2 adrenergic receptors (alpha2 AR) mediate incorporation of guanosine 5'-O-(gamma-thio)triphosphate ([35S]GTPgammaS) into isolated membranes via receptor-catalyzed exchange of [35S]GTPgammaS for GDP. In the current study, we used [35S]GTPgammaS incorporation to characterize the intrinsic activity and potency of agonists and antagonists at the cloned mouse alpha2a/d and human alpha2a, alpha2b, and alpha2c ARs. Full agonists increased [35S]GTPgammaS binding to membranes by 2- to 3-fold. Antagonists did not increase [35S]GTPgammaS binding but competitively inhibited agonist-stimulated [35S]GTPgammaS binding. Compounds with intrinsic activities less than that of the full agonists norepinephrine (NE) or epinephrine (EPI) were capable of antagonizing agonist-stimulated [35S]GTPgammaS binding. The agonistic properties of a number of alpha2 AR ligands were characterized at each alpha2 AR subtype. The rank order of agonist potency for selected compounds at the human receptors (with intrinsic activity compared with NE, defined as 1.0) was: alpha2a: Dexmedetomidine (0.73) > guanabenz (0.38) > UK-14304 (1.02) > clonidine (0.32) > ST-91 (0.63) > NE (1.00). alpha2b: Dexmedetomidine (1.10) > clonidine (0.18) > guanabenz (0.71) > NE (1.00) > ST-91 (0.44) > UK-14304 (0.59). alpha2c: Dexmedetomidine (1.03) > NE (1.00) > UK-14304 (0.75) > ST-91 (0.32) > or = clonidine (0.23) >> guanabenz (0). This report provides a functional characterization of adrenergic receptor ligands at human and mouse alpha2a/d AR. It also illustrates the utility of [35S]GTPgammaS incorporation as a functional marker of receptor activation.

Clinical use of the neuromuscular blocking agents atracurium and pancuronium for equine anesthesia.

Neuromuscular blocking agents (muscle relaxants) are useful and common adjuncts to general anesthesia for human beings, but have not been used extensively during anesthesia of large animal species. Over a 3-year period, atracurium or pancuronium were used as adjuncts to general anesthesia for 89 anesthetic procedures in 88 equids (of 18 breeds and age ranging in age from 5 weeks to 25 years) at the teaching hospital. Forty-one of the anesthetic procedures were for abdominal surgery, and orthopedic (n = 19), ophthalmologic (n = 17), thoracotomy (n = 1), and soft tissue (n = 14) procedures composed the rest. Most equids were given atracurium because it was less expensive than pancuronium. Initial dosage of either relaxant ranged from 0.12 to 0.2 mg/kg of body weight IV, and repeat doses ranged from 10 to 30 mg. Relaxants were used for as long as 205 minutes. Muscles of the face or hind limb digital extensor muscles were used to monitor relaxation. Muscles of the hind limb were more sensitive to the effects of relaxants than were muscles of the face. At the end of a surgical procedure, just prior to being taken to the recovery stall, a relaxant antagonist, edrophonium (0.5 to 1 mg/kg), was administered IV to each equid. Edrophonium caused blood pressure to increase in most of the equids. Heart rate change was variable, with approximately half the equids having no change or increased heart rate and the remainder having decreased heart rate. Recovery to standing after anesthesia was rated excellent or good for 72 equids, fair for 11, and poor for 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Thermal burns in four dogs during anesthesia.

Thermal burns occurred in four anesthetized dogs as a result of using latex surgical gloves filled with warm water to treat hypothermia. The burns were on relatively hairless skin that had been in contact with the gloves. Small containers full of warm water are a relatively inefficient source of heat, but if the temperature of the water exceeds 45 degrees C and the container contacts the animal's skin, thermal injury can result.