The Cardiopulmonary Effects of Oxymorphone in Hypovolemic Dogs

Blood was withdrawn from 15 dogs over the course of about 1 hour until the mean arterial blood pressure was reduced to 60 mm Hg. Small aliquots of additional blood were withdrawn in order to maintain the mean arterial blood pressure near 60 mm Hg for an additional hour. Oxymorphone (0.4 mg/kg) was then administered intravenously to ten dogs, and all measurements were repeated in 5, 15, 30, and 60 minutes. Five dogs served as controls.
Heart rate, tidal volume, arterial oxygen, oxygen extraction, and pH significantly decreased after oxymorphone administration, while systemic and pulmonary arterial blood pressures, systemic vascular resistance (transiently), breathing rate, minute ventilation, physiologic dead space, venous admixture, venous oxygen, arterial and venous carbon dioxide, and bicarbonate concentration increased significantly. Cardiac output was also increased, but the change was not statistically significant. Oxymorphone was associated with significantly lower heart rate, tidal volume, arterial oxygen, and pH, and higher systemic and pulmonary arterial pressure, cardiac output, venous oxygen, and arterial and venous carbon dioxide, compared to the control group, which did not receive oxymorphone.
Oxymorphone significantly improved cardiovascular performance and tissue perfusion in these hypovolemic dogs. Oxymorphone did cause a significant increase in arterial carbon dioxide and a decrease in arterial oxygenation. Oxymorphone is an opioid agonist that may represent a reasonable alternative for the induction of anesthesia in patients who are candidates for induction hypotension.     

Open Heart Surgery with Deep Hypothermia and Cardiopulmonary Bypass in Small and Toy Dogs

Objective: To evaluate open heart surgery with deep surface‐induced hypothermia (sHT) and low‐flow cardiopulmonary bypass (CPB) in small and toy‐breed dogs. Study Design: Case series. Animals: Small breed dogs (n=8) weighing <5.5 kg with naturally occurring cardiac disease. Methods: Deep sHT under isoflurane anesthesia and low‐flow rate CPB with a small‐volume prime circuit were used. Ventricular septal defect was closed directly in 2 dogs and severe mitral regurgitation was corrected with mitral valvuloplasty (MVP) in 5 dogs and mitral valve replacement in 1 dog. Results: All dogs survived surgery; 1 dog died 6 days and 1 died 2 months after MVP. The other 6 dogs lived (mean follow‐up, 32.8 months; range, 12–65 months). Mean body weight at surgery was 3.6 kg (range, 2–5.3 kg). Mean lowest esophageal temperature was 21.4°C (range, 19.8–23.8°C). Mean lowest pump flow volume was 29.2 mL/kg/min (range, 9.4–57.7 mL/kg/min) during aortic cross‐clamping (mean, 53.5 minutes; range, 25–79 minutes). Mean hematocrit before CPB was 38.6% (range, 33–47%) and 20.3% (range, 13–24%) during CPB with a small circuit priming volume of 225–260 mL. Conclusion: Deep sHT with low‐flow rate CPB may be used for open heart surgery in small dogs weighing <5.5 kg. Clinical Relevance: Open heart surgery for selected congenital defects and acquired defects in small and toy‐breed dogs may be successfully performed using deep sHT and CPB.     

Mass Euthanasia of Dogs with Carbon Monoxide and/or Carbon Dioxide; Preliminary Trials

Abstract— Conditions necessary in alternatives to the present unsatisfactory methods of killing unwanted dogs in Asia are suggested. A chamber used in Japan for trials with CO and CO₂ is described and the procedure outlined. Pure CO was produced by the action of excess sulphuric acid on sodium formate and acid fumes were removed by passing the gas through 10% NaOH. Carbon dioxide was used from pressurised cylinders. Twenty-seven dogs were killed by CO, eleven by CO₂ and two by combination of CO and CO₂. With CO an estimated 2% caused death without distress in an average of 31 min and with an estimated 3% CO death occurred after an average of 14–5 min although one of two dogs howled. Measures to control this effect are discussed. With CO₂ the most satisfactory result was achieved at 70% with air when death occurred after 5 min. A combination of 40% CO₂ and approximately 3% CO caused death in an average of 4–5 min without distress. Hazards to human personnel are assessed and it is concluded that the risks are not greater than those met in every day activities. It is also concluded that further investigations and development are necessary before euthanasia by either gas can be recommended for general use and reference is made to the nature of the required modifications in apparatus and technique. Résumé— L'auteur étudie les conditions à prtvoir pour remplacer les méthodes peu satisfaisantes appliquées en Asie dans la destruction des chiens abandonnés. II décrit la méthode de la chambre à gaz utilisée au Japon, qui comporte des traînées de GO et de CO₂. Le GO pur est produit par l'action de l'acide sulfurique excédentaire sur le formiate de sodium, les vapeurs acids étant éliminées par le passage du gaz dans du NaOH à 10 %. Le CO₂ provient de cylindres à gaz comprimé. Vingt-sept chiens ont été detruits au CO, onze au CO₂, et deux avec un mélange de l'un et de l'autre. Le GO à 2 pour cent (dose estimative) a provoqué la mort sans souffrance en une moyenne de 31 minutes; le GO à 3 pour cent (dose estimative) a agi en un temps moyen de 14, 5 minutes, mais l'un des deux chiens a hurlé. L'auteur examine les moyens propres àéliminer les insufisances de cette technique. Le CO₂ a donné les meilleurs résultats à 70 pour cent, avec delair: les chiens sont morts en 5 minutes. Un mèlange de CO₂à 40 pour cent et de GO à environ 3 pour cent a provoqué la mort sans souffrance en un temps moyen de 4, 5 minutes. L'auteur évalue les risques que présente cette méthode pour le personnel; il conclut que ces risques ne dépassent pas ceux que cornportent nos activités quotidiennes. L'auteur constate en outre qu'il y a lieu de poursuivre l'étude et le développement de cette méthode avant que l'on puke recommander la généralisation de l'euthanasie par I'un ou l'autre des gaz examinés. II évoque les modifications qu'appellent les appareils et les techniques actuelles. Zusammenfassung— Die zur Äderung der gegenwartigen unbefriedigenden Methoden der Tötung unerwünschter Hunde in Asien notwendigen Bedingungen werden angegeben. Es wird eine in Japan für streunende Tiere verwendete GO-und CO₂-Kammer beschrieben und das Ver-fahren angegeben. Reines CO wurde durch die Einwirkung überschüssiger Schwefelsäure auf Natriumformiat erzeugt, und die Säuredämpfe wurden durch Waschen des Gases mit 10% NaOH entfernt. Die Kohlensäure wurde Druckflaschen entnommen. 27 Hunde wurden rnit GO, 11 mit GO₂ und 2 mit einer Kombination von CO und CO₂ getötet. Eine geschätzte GO-Konzentration von 2% verursachte schmerzlosen Tod in durchschnittlich 31 Minuten, und rnit einer geschätzten CO-Konzentration von 3% trat der Tod nach durchschnittlich 14, 5 Minuten ein, wobei jedoch einer von zwei Hunden heulte. Messungen zur Besti-mmung dieser Wirkung werdenbesprochen. Bei Verwendung von CO₂ wurde das zufriedenstellendste Ergebnk bei einer Konzentration von 70% in Luft erzielt, bein welcher der Tod nach 5 Minuten ein trat. Eine Kombination von 40% (20% und etwa 3% CO verunachte schmerzlosen Tod in durchschnittlich 4, 5 Minuten. Die Gefahren für das Personal werden erläutert und der Schluss gezogen, dass die Risiken nicht grösser als die bei sonstiger täglicher Arbeit sind. Der Verfasser gelangt ferner zu dem Schluss, dass weitere Untersuchungen und Entwicklungs-arbeit notwendig sind, ehe die Euthanasie rnit diesen beiden Gasen zum allgemeinen Gebrauch empfohlen werden kann. Hinweise auf die Art der erforderlichen Änderungen des Apparats und der Technik werden gegeben.     

Survival Following Cardiopulmonary Resuscitation in Dogs and Cats

Dogs and cats receiving cardiopulmonary resuscitation (CPR) were evaluated for factors leading to cardiac arrest and for survival following the procedure. One-hundred-thirty-five canine and forty-three feline patients seen at the University of California, Davis Veterinary Medical Teaching Hospital that received CPR between August 1987 and December 1991 were studied. Initial resuscitation attempts were unsuccessful in 72% of dogs and 58% of cats. Five dogs and one cat were still alive 3 days after CPR. Ultimately only four dogs and one cat were discharged from the hospital alive. These five patients with uniquely longer survival all had cardiac arrests associated with drug and/or anesthetic reactions.     

Full-thickness Thoracic and Abdominal Wall Reconstruction in Dogs Using Carbon/Polycaprolactone Composite

Square 9 × 9 cm full-thickness defects were created in the thoracic wall of five dogs and the abdominal wall of five dogs. The skin was retained. Ten centimeter squares of carbon fabric with a thin polycaprolactone (PCL) lining were sutured into the defects with the PCL lining facing the viscera. The dogs were observed for 5 months. The surgical technique was simple and fast. All implants were well tolerated. Cosmetic results were excellent in nine dogs. One dog (abdominal implant) developed an infection and draining tract, and a second dog (thoracic implant) had a subclinical infection. Thoracic implants caused brief serosanguinous pleural transudate. Mild paradoxical respiratory motion disappeared by 8 weeks. Lungs were radiographically normal. At necropsy, fibrous tissue was present but lacked orientation. Loose adhesions covered 20 to 80% of implant linings. There was no significant difference in ultimate tensile strength of implant/fibrous tissue compared to control abdominal wall. No carbon fragments were observed in lymph nodes. Increased numbers of secondary follicles, plasma cells, eosinophils, and sinus histiocytes in lymph nodes suggested immunologic stimulation of undetermined significance.     

Laparoscopic Cholecystectomy for Management of Uncomplicated Gall Bladder Mucocele in Six Dogs

Objectives— To describe a technique for, and outcome after, laparoscopic cholecystectomy (LC) for management of uncomplicated gall bladder mucocele (GBM) in dogs. Study Design— Case series. Animals— Dogs (n=6) with uncomplicated GBM. Methods— Dogs with ultrasonographic evidence of GBM but without imaging or laboratory signs of gall bladder rupture, peritonitis, or extra‐hepatic biliary tract rupture that had LC were included. A 4 portal technique was used. A fan retractor was used to retract the gall bladder to allow dissection around the cystic duct with 5 or 10 mm right‐angle dissecting forceps. The cystic duct was ligated using extracorporeally tied ligatures supplemented sometimes with hemostatic clips. A harmonic scalpel was used to dissect the gall bladder from its fossa. The gall bladder was placed into a specimen retrieval bag and after bile aspiration the bag was withdrawn through the 11 mm portal incision. Results— Five dogs had mild intermittent clinical signs including vomiting, inappetence, and lethargy. All dogs had successful LC without conversion to an open approach. All dogs with clinical signs had improvement or resolution of signs postoperatively. No important perioperative complications occurred and all dogs were alive at a median of 8 months postoperatively (range, 3–14 months). Conclusions— LC can be accomplished safely and effectively in dogs with uncomplicated GBM. Clinical Relevance— A minimally invasive approach for cholecystectomy can be used for the treatment of GBM in dogs.     

Surgery and Doxorubicin in Dogs With Hemangiosarcoma

Forty-six dogs with histologically confirmed hemangiosarcoma of various locations other than skin were used in a prospective study to determine the efficacy of adjuvant doxorubicin (30 mg/m² IV q 3 weeks for 5 treatments) 10 to 14 days after the tumor was partially or completely excised. Analysis of the data included information on variables that were hypothesized to influence response to therapy, disease-free interval (DFI), or survival time (ST). Other information collected included age, gender, breed, weight, prior therapy, type of surgery, location of the primary tumor, presence of metastases, number of doses of doxorubicin, response to doxorubicin therapy (complete or partial response!, and the following histological criteria: overall differentiation, nuclear pleomorphism, percent necrosis, mitotic score, total histological score, and grade. Surgery outcome (complete versus incomplete surgical excision) markedly influenced survival times (P < .001). Twenty percent of the dogs rendered free of disease were alive at 1 year, whereas none of the dogs that had residual tumor after surgery were alive at 1 year. Most of the histological criteria (nuclear pleomorphism, mitotic score, grade, overall differentiation) had marked (P < .05), or close to marked, independent associations with ST for dogs that had complete tumor removal. Results from analysis of DFI were generally similar to those of ST in dogs with complete excision of the tumor. Twenty-seven of the 46 dogs (58.7%) had all clinical evidence of tumor successfully removed. Logistic regression analysis of surgical outcome (ability to remove all visible tumor) suggested that age of the subject was the only factor markedly influencing surgical outcome (P= .017). As age increased, the probability of success increased. Those dogs that had previous treatment for their hemangiosarcoma tended (P= .08) to have a shorter DFI and ST. Therefore, complete removal of all evidence of tumor followed by 5 doses of doxorubicin may be an effective treatment for dogs with hemangiosarcoma. Dogs that had all tumor successfully removed had a mean and median ST of 267 and 172 days, respectively. Dogs with incomplete tumor removal had a mean and median ST of 172 and 60 days, respectively. Similarly, prognostic variables such as the ability to completely excise all evidence of tumor, histological criteria, and age of the patient are potentially important prognostic variables for predicting outcome.     

A Comparison of Laparoscopic and Belt-Loop Gastropexy in Dogs

A simplified technique for laparoscopic gastropexy (group 1) was compared to belt-loop gastropexy (group 2) in eight adult male dogs randomly divided into two groups of four dogs each. Our hypothesis was that a satisfactory laparoscopic gastropexy would approximate the strength and operative time required for belt-loop gastropexy. Operative time, surgical complications, postoperative morbidity, gross and histological appearance, radiographic microvascularization, and maximal tensile strength were measured and compared between the two groups. All dogs recovered from surgery. No morbidity was associated with either procedure. The mean (±SD) duration of surgery was 69.75 ± 7.23 minutes for group 1 and 58.75 ± 7.63 minutes for group 2. Fifty days after surgery, the microvascular appearance of the gastropexy site was similar for both groups. Blood vessels were observed within each seromuscular flap but vascular ingrowth to the abdominal musculature was observed in only two dogs, one from each group. The maximum tensile strength at 50 days was 76.55 ± 22.78 for group 1 and 109.21 ± 22.29 N for group 2. Differences between surgical duration and maximum tensile strength were not statistically significant ( P >.05). Histologically, all gastropexies consisted of an adhesion composed of dense fibrous connective tissue. The results of this study indicate that laparoscopic gastropexy provides a minimally invasive alternative to open abdominal prophylactic gastropexy in dogs.     

大黄注射液对犬血管搭桥术后纤溶系统的影响

为研究大黄注射液对犬血管搭桥术后纤溶系统的影响,将20只犬随机分为高(0.8 g.kg-1)、中(0.4g.kg-1)、低剂量组(0.08 g.kg-1)及对照组,同侧自体颈外静脉重建颈总动脉,头静脉滴注大黄注射液,ELISA定量分析测定术前及术后1、2、3、5、7、14、21 d纤溶系统各指标的变化。结果显示,用药后血小板α颗粒膜蛋白、D-二聚体、纤溶酶原激活剂的抑制物-1显著降低,组织纤溶酶原激活剂显著升高,且成剂量依赖关系;血清纤维蛋白(原)降解产物无显著变化。结果表明,大黄注射液能纠正搭桥术后血液高凝状态,恢复抗凝系统活性,预防血栓形成。     

Changes in Cardiopulmonary Variables and Platelet Count During Anesthesia for Total Hip Replacement in Dogs

Changes in cardiopulmonary function and platelet count were determined in 22 dogs of various breeds that underwent total hip replacement with cemented femoral prostheses. In 11 dogs (group I) polymethylmethacrylate (PMMA) was inserted without venting the reamed and lavaged femoral canal. In a second group of 11 dogs (group II) a urethral catheter (ID: approximately 2.7 mm) was placed into the medullary cavity before the insertion of PMMA. The application of PMMA resulted in a decrease in end-tidal carbon dioxide tension (PETco₂) until 5 minutes after insertion of bone cement. Increases in arterial to end-tidal pCO₂ gradient [P(a-ET)co₂] and physiological dead space (V_D/V_T) were recorded between 2 minutes before and 5 minutes after insertion of PMMA in 12 dogs. A significant decrease in platelet count occurred in both groups of dogs. Decreases in arterial pO₂ (Pao₂), arterial/alveolar oxygen tension ratio (Pao₂/PAo₂), and percent O₂ saturation of hemoglobin in arterial blood (Sao₂) were not statistically significant. No significant differences could be detected between data obtained from both groups of dogs. An increase in femoral intramedullary pressure caused by the insertion of PMMA and subsequent pulmonary microembolism by medullary contents has been considered the most likely cause for changes in pulmonary function. The lack of statistically significant differences in cardiopulmonary variables and platelet count between the two groups of dogs could have been related to inefficient pressure reduction by the method used.     

Effects of Carbon Dioxide Insufflation and Body Position on Blood Gas Values in Horses Anesthetized for Laparoscopy

The objective of the study was to describe the effects of carbon dioxide pneumoperitoneum and Trendelenburg position on arterial blood gas values in horses anesthetized for laparoscopy. The study design was a prospective case series using 14 healthy adult horses anesthetized for elective laparoscopic surgery. All horses in the study were maintained under anesthesia with halothane in oxygen with intermittent positive-pressure ventilation. A pneumoperitoneum of 15 mmHg or less was achieved with carbon dioxide, and horses were tilted to a 35-degree Trendelenburg position to allow the completion of laparoscopic cryptorchidectomy (n = 13) or ovariectomy (n = 1). Heart rate, mean arterial pressure, and arterial blood gases were recorded at six time intervals throughout the procedure. Results of the study indicated a pH that decreased and partial pressure of carbon dioxide (PaCO₂) and mean arterial pressure that increased over time and differed significantly from baseline during Trendelenburg position. Partial pressure of oxygen (PaO₂) was significantly lower than baseline after assumption of Trendelenburg position and did not improve on return to normal recumbency and abdominal pressure. As body weight increased, pH and PaO₂ decreased and PaCO₂ increased. We concluded that horses placed in Trendelenburg position have changes that are transient, with the exception of PaO₂. Heavier horses have a greater change in pH, PaCO₂, and PaO₂ than lighter horses during abdominal insufflation and Trendelenburg position. The changes incurred during CO₂ abdominal insufflation and Trendelenburg position are transient, with the exception of a decreased PaO₂. Heavy horses undergoing abdominal insufflation and Trendelenburg position should be closely monitored for critical cardiopulmonary values.