A modified LVAD technique to augment caval and pulmonary arterial blood flow in the "failing Fontan" circulation.

BACKGROUND: There are minimal circulatory support options for patients with a failing Fontan. The Heartmate II (HMII) left ventricular assist device (Thoratec, Bedford, MA) in its packaged state cannot augment caval/pulmonary arterial blood flow. AIM: We hypothesized that a modified HMII pump could augment caval and pulmonary arterial blood flow. METHODS: A bifurcated ringed Gore-Tex graft (W. L. Gore & Associates, Flagstaff, AZ) was sewn to the HMII inflow, and the outflow graft transected and tapered from 16 mm to 8 mm in diameter. In three sheep, the inflow and outflow grafts were anastomosed end-to-side to both cava and the pulmonary artery. RESULTS: Following baseline measurements, the pump speed was increased to 8000 revolutions per minute (RPMs). Compared to baseline, at 8000 RPMs, there were no significant differences in mean arterial, central venous, or pulmonary arterial pressure. However, there was a significant decrease in right ventricular diastolic diameter (3.1 ± 0.1 vs. 1.8 ± 0.2 cm, R = 0.6, p = 0.02) and similarly a decrease in pulmonary arterial pulse pressure (8.5 ± 2.1 vs. 2.1 ± 2.9 mmHg, p = 0.01). As pump speed increased, there was a corresponding increase in pump flow and power, with a decrease in pulsatility index. CONCLUSIONS: These findings suggest that the HMII may be modified to provide caval/pulmonary circulatory support for the failing Fontan circulation.

Safety and clinical effectiveness of a compounded sustained-release formulation of buprenorphine for postoperative analgesia in New Zealand White rabbits.

OBJECTIVE: To determine the clinical effectiveness and safety of a compounded sustained-release formulation of buprenorphine, compared with effects of regular buprenorphine, for postoperative analgesia in rabbits. DESIGN: Blinded randomized controlled clinical trial. ANIMALS: 24 purpose-bred adult male New Zealand White rabbits. PROCEDURES: Rabbits received titanium implants in each tibia as part of another study. Immediately prior to surgery, each rabbit received regular buprenorphine hydrochloride (0.02 mg/kg [0.009 mg/lb], SC, q 12 h for 3 days) or 1 dose of a compounded sustained-release formulation of buprenorphine (0.12 mg/kg [0.055 mg/lb], SC) followed by an equal volume of saline (0.9% NaCl) solution (SC, q 12 h for 3 days) after surgery. For 7 days after surgery, rabbits were evaluated for signs of pain by means of rabbit grimace and activity scoring and for adverse effects. RESULTS: No significant differences were identified between treatment groups in grimace and activity scores at any point. No major adverse effects were detected for either drug. However, 3 rabbits that received regular buprenorphine had pain scores suggestive of moderate to severe pain by the time dose administration was due (ie, within the 12-hour administration interval). No clinically important differences were detected in intraoperative anesthetic or postoperative recovery variables. CONCLUSIONS AND CLINICAL RELEVANCE: Sustained-release buprenorphine administered SC at 0.12 mg/kg was at least as effective as regular buprenorphine in providing analgesia for rabbits following orthopedic surgery without any major adverse effects. This sustained-release formulation represents an important alternative for rabbit analgesia with potential to improve rabbit welfare over existing analgesic standards.

Sheep (Ovis aries) as a model for cardiovascular surgery and management before, during, and after cardiopulmonary bypass.

Because of its similarity to humans in important respects, sheep (Ovis aries) are a common animal model for translational research in cardiovascular surgery. However, some unique aspects of sheep anatomy and physiology present challenges to its use in these complicated experiments. In this review, we discuss relevant anatomy and physiology of sheep and discuss management before, during, and after procedures requiring cardiopulmonary bypass to provide a concise source of information for veterinarians, technicians, and researchers developing and implementing protocols with this model.

Analgesic use in nonhuman primates undergoing neurosurgical procedures.

Animals experiencing major invasive surgery during biomedical research must receive appropriate and sufficient analgesia. The concept of pain management in veterinary medicine has evolved over the past several decades, and a multimodal, preemptive approach to postoperative analgesia is the current standard of care. Here, the pathophysiology of pain and a multimodal approach to analgesia for neurosurgical procedures is discussed, with emphasis on those involving nonhuman primates.