Postoperative oxygenation in healthy dogs following mechanical ventilation with fractions of inspired oxygen of 0.4 or >0.9.

OBJECTIVE: To evaluate arterial oxygenation during the first 4 postoperative hours in dogs administered different fractions of inspired oxygen (FiO2) during general anesthesia with mechanical ventilation. STUDY DESIGN: Prospective, randomized clinical trial. ANIMALS: A total of 20 healthy female dogs, weighing >15 kg and body condition scores 3-7/9, admitted for ovariohysterectomy. METHODS: Dogs were randomized to breathe an FiO2 >0.9 or 0.4 during isoflurane anesthesia with intermittent positive pressure ventilation. The intraoperative PaO2:FiO2 ratio was recorded during closure of the linea alba. Arterial blood was obtained 5, 60 and 240 minutes after extubation for measurement of PaO2 and PaCO2 (FiO2 = 0.21). Demographic characteristics, duration of anesthesia, PaO2:FiO2 ratio and anesthetic agents were compared between groups with Wilcoxon tests. The postoperative PaO2, PaCO2, rectal temperature, a visual sedation score and events of hypoxemia (PaO2 < 80 mmHg) were compared between groups with mixed-effects models or generalized linear mixed models. RESULTS: Groups were indistinguishable by demographic characteristics, duration of anesthesia, anesthetic agents administered and intraoperative PaO2:FiO2 ratio (all p > 0.08). Postoperative PaO2, PaCO2, rectal temperature or sedation score were not different between groups (all p > 0.07). During the first 4 postoperative hours, hypoxemia occurred in three and seven dogs that breathed FiO2 >0.9 or 0.4 during anesthesia, respectively (p = 0.04). CONCLUSIONS AND CLINICAL RELEVANCE: The results identified no advantage to decreasing FiO2 to 0.4 during anesthesia with mechanical ventilation with respect to postoperative oxygenation. Moreover, the incidence of hypoxemia in the first 4 hours after anesthesia was higher in these dogs than in dogs breathing FiO2 >0.9.

Idiopathic Canine Laryngeal Paralysis as One Sign of a Diffuse Polyneuropathy: An Observational Study of 90 Cases (2007-2013).

OBJECTIVE: To determine survival and incidence of complications in dogs with idiopathic laryngeal paralysis (ILP) and concurrent neurologic signs. STUDY DESIGN: Observational study. ANIMALS: Dogs (n = 90) with ILP. METHODS: Medical records (January 2007-June 2013) of dogs with ILP were reviewed. Neurologic comorbidities, including pelvic limb neurologic abnormalities and esophageal abnormalities were identified. Using medical record information and client interviews, the relationship between these comorbidities and postoperative survival (primary outcome measure) and postoperative complications (secondary outcome measure) was identified. RESULTS: Dogs that had surgical correction of ILP had a 2.6-fold reduction in the hazard of death throughout the study period (HR = 2.6; 95% CI: 1.34-4.84, P = .006). Owner assessed patient quality of life (10-point scale) increased by an average of 4.1 ± 1.4 units immediately postoperatively, and 4.9 ± 0.9 units until death or followup compared with preoperative values. Thirty-five of 72 dogs available for followup had evidence of diffuse neurologic comorbidities. Overall complication rate for dogs with neurologic comorbidities was 74%, compared with 32% for dogs without neurologic comorbidities. Presence of any neurologic comorbidity was associated with a significantly greater odds of any complication (OR = 4.04; 95% CI: 1.25-13.90, P = .019) as well as recurring complications (OR = 8.00; 95% CI: 1.49-54.38; P = .015). CONCLUSION: Surgical correction of ILP was positively associated with survival, and dogs with neurologic comorbidities were at greater risk for developing postoperative complications.

Clinical features, concurrent disorders, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome.

OBJECTIVE: To characterize clinical features, comorbidities, frequency of bacterial isolation, and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS). ANIMALS: 168 client-owned cats with S-CCHS. PROCEDURES: Data were prospectively (1980 to 2019) collected regarding clinical features, comorbidities, bacterial infection, illness duration, and treatments. Variables were evaluated for associations with survival time. RESULTS: Median age of cats was 10.0 years, with no breed or sex predilection observed. Common clinical features included hyporexia (82%), hyperbilirubinemia (80%), lethargy (80%), vomiting (80%), jaundice (67%), weight loss (54%), and hypoalbuminemia (50%). Comorbidities included extrahepatic bile duct obstruction (53%), cholelithiasis (42%), cholecystitis (40%), and ductal plate malformation (44%) as well as biopsy-confirmed inflammatory bowel disease (60/68 [88%]) and pancreatitis (41/44 [93%]). Bacterial cultures were commonly positive (69%) despite prebiopsy antimicrobial administration in most cats. Of surgically confirmed choleliths, diagnostic imaging identified only 58%. Among 55 cats with "idiopathic pancreatitis," 28 (51%) were documented to have transiting choleliths, and 20 had pancreatic biopsies confirming pancreatitis. Cholelithiasis (with or without bile duct obstruction) and cholecystectomy were associated with survival advantages. Survival disadvantages were found for leukocytosis, ≥ 2-fold increased alkaline phosphatase, and hyperbilirubinemia. Cholecystoenterostomy had no survival impact. Cats with ductal plate malformations were significantly younger at diagnosis and death than other cats. Chronic treatments with antimicrobials, S-adenosylmethionine, and ursodeoxycholic acid were common postbiopsy. CLINICAL RELEVANCE: S-CCHS in cats was associated with bacterial infection and various comorbidities and may be confused with pancreatitis. Surgically correctable morbidities (ie, cholecystitis, cholecystocholelithiasis) and cholecystectomy provided a significant survival advantage.

Relationships between congenital peritoneopericardial diaphragmatic hernia or congenital central diaphragmatic hernia and ductal plate malformations in dogs and cats.

OBJECTIVE: To characterize the association between peritoneopericardial diaphragmatic hernia (PPDH) or congenital central diaphragmatic hernia (CCDH) and ductal plate malformations (DPMs) in dogs and cats. ANIMALS: 18 dogs and 18 cats with PPDH or CCDH and 19 dogs and 18 cats without PPDH or CCDH. PROCEDURES: Evaluation of clinical details verified PPDH or CCDH and survival times. Histologic features of nonherniated liver samples were used to categorize DPM. Immunohistochemical staining for cytokeratin-19 distinguished bile duct profiles per portal tract and for Ki-67-assessed cholangiocyte proliferation. Histologic features of herniated liver samples from PPDH or CCDH were compared with those of pathological controls (traumatic diaphragmatic hernia, n = 6; liver lobe torsion, 6; ischemic hepatopathy, 2). RESULTS: DPM occurred in 13 of 18 dogs with the proliferative-like phenotype predominating and in 15 of 18 cats with evenly distributed proliferative-like and Caroli phenotypes. Congenital hepatic fibrosis DPM was noted in 3 dogs and 2 cats and renal DPM in 3 dogs and 3 cats. No signalment, clinical signs, or clinicopathologic features discriminated DPM. Kaplan Meier survival curves were similar in dogs and cats. Bile duct profiles per portal tract in dogs (median, 5.0; range, 1.4 to 100.8) and cats (6.6; 1.9 to 11.0) with congenital diaphragmatic hernias significantly exceeded those in healthy dogs (1.4; 1.2 to 1.6) and cats (2.3; 1.7 to 2.6). Animals with DPM lacked active cholangiocyte proliferation. Histologic features characterizing malformative bile duct profiles yet without biliary proliferation were preserved in herniated liver lobes in animals with DPM. CONCLUSIONS AND CLINICAL RELEVANCE: DPM was strongly associated with PPDH and CCDH. Because DPM can impact health, awareness of its coexistence with PPDH or CCDH should prompt biopsy of nonherniated liver tissue during surgical correction of PPDH and CCDH.

Effects of two fractions of inspired oxygen during anesthesia on early postanesthesia oxygenation in healthy dogs.

OBJECTIVE To evaluate the effects of 2 fractions of inspired oxygen (Fio2s) during anesthesia on postanesthesia Pao2 and other measures of oxygen exchange. ANIMALS 22 healthy adult sexually intact female dogs undergoing ovariohysterectomy by ventral midline celiotomy. PROCEDURES Dogs were randomly assigned to receive either oxygen (Fio2 > 0.9 [100% oxygen]; n = 11; control group) or a mixture of nitrogen and oxygen (Fio2 = 0.4; 11; 40% oxygen group) as the carrier gas for isoflurane while anesthetized. All dogs were allowed to breathe spontaneously while anesthetized. For each dog, the Pao2, Paco2, other indices of oxygenation, and extent of sedation were monitored at predetermined times during and for 1 hour after anesthesia. Measured variables were compared between the 2 treatment groups and over time within each treatment group. RESULTS None of the measured variables differed significantly between the control and 40% oxygen groups at any time during the postanesthesia period. Within each treatment group, the Paco2 and extent of sedation decreased over time during the postanesthesia period. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that indices of oxygenation did not differ significantly between healthy dogs in which the Fio2 was maintained at > 0.9 and those in which the Fio2 was maintained at 0.4 while anesthetized for ovariohysterectomy. Thus, the addition of nitrogen to the carrier gas for an inhalant anesthetic conferred neither an advantage nor disadvantage in regard to oxygenation during the first hour of anesthesia recovery.

Gallbladder disease in Shetland Sheepdogs: 38 cases (1995-2005).

OBJECTIVE: To determine risk, clinical features, and treatment responses for gallbladder disorders in Shetland Sheepdogs. DESIGN: Retrospective case-control study. ANIMALS: 38 Shetland Sheepdogs with gallbladder disease. PROCEDURES: Medical records were reviewed for signalment, history, physical findings, laboratory results, imaging features, coexistent illnesses, histologic findings, treatments, and survival rates. RESULTS: Mature dogs with gastrointestinal signs were predisposed (odds ratio, 7.2) to gallbladder disorders. Gallbladder mucocele was confirmed in 25 dogs. Concurrent problems included pancreatitis, hyperlipidemia, corticosteroid excess, hypothyroidism, protein-losing nephropathy, diabetes mellitus, cholelithiasis, and gallbladder dysmotility. Mortality rate was 68% with and 32% without bile peritonitis. Nonsurvivors had high WBC and neutrophil count and low potassium concentration. Although preprandial hypercholesterolemia, hypertriglyceridemia, and high serum liver enzyme activities were common, gallbladder disease was serendipitously discovered in 11 of 38 dogs. Histologic examination (n=20 dogs) revealed gallbladder cystic mucosal hyperplasia in 20 dogs, cholecystitis in 16, periportal hepatitis in 9, and vacuolar hepatopathy in 7. Surgery included cholecystectomy (n=17) and cholecystoenterostomy (4). In 1 hyperlipidemic dog without clinical signs, gallbladder mucocele resolved 6 months after beginning use of a fat-restricted diet and ursodeoxycholic acid. CONCLUSIONS AND CLINICAL RELEVANCE: Shetland Sheepdogs are predisposed to gallbladder disorders, with mucoceles and concurrent dyslipidemia or dysmotility in many affected dogs. Most dogs were without clinical signs during mucocele development. Low survival rate after cholecystectomy in clinically affected dogs suggested that preemptive surgical interventions may be a more appropriate treatment strategy.

Use of recombinant tissue-plasminogen activator in a dog with chylothorax secondary to catheter-associated thrombosis of the cranial vena cava.

A 4-year-old, castrated male Maltese developed cranial vena caval thrombosis and chylothorax following central venous catheterization for treatment of postoperative sepsis. Vena caval thrombolysis was attempted using recombinant human tissue-plasminogen activator (t-PA). Thrombolytic therapy led to an acute reduction in the size of the caval thrombus and was followed by prompt resolution of the chylothorax. Hemorrhage at the entry sites of a jugular catheter and esophagostomy tube placed at the time of treatment was a dose-limiting complication of t-PA therapy in this dog.