Effect of increased resistance on dynamic compliance assessed by two clinical monitors during volume-controlled ventilation: A test-lung study.

OBJECTIVE: To evaluate the effect of increased respiratory system resistance (RRS) on dynamic compliance (Cdyn) assessed by the NM3 monitor (Cdyn(NM3)) and the E-CAiOV module (Cdyn(ECAiOV)). STUDY DESIGN: Prospective laboratory study. METHODS: A training test lung (TTL) simulated the mechanical ventilation of a mammal with 50 and 300 mL tidal volumes in three conditions of RRS [normal (RBL), moderately increased (R1) and severely increased (R2)] and a wide range of clinically relevant Cdyn. Simulations at increased RRS were paired with simulations at RBL with the same static compliance for comparisons. Pearson's correlation coefficient and concordance correlation coefficient between the measurements at RBL with the ones with increased RRS were calculated. Bland-Altman plots were also used to evaluate the agreement of Cdyn(ECAiOV) and Cdyn(NM3) at RBL (control values) with their paired values at R1 and R2. Relative bias and limits of agreement (LOAs) were calculated and LOAs larger than 30% were considered unacceptable. Trending ability of Cdyn(NM3) and Cdyn(ECAiOV) were evaluated by polar plots. Values of p < 0.05 were considered significant. RESULTS: The effect of increased RRS was more pronounced for Cdyn(ECAiOV) than for Cdyn(NM3). Unacceptable agreement was only observed in Cdyn(NM3) at R2 in the 300 mL simulation (bias = -18.3% and lower LOA = -45%). For Cdyn(ECAiOV), agreement was unacceptable for all tested RRS in both simulations, being the worst at R2 in the 300 mL simulation (bias = -54.7% and lower LOA = -100.2%). Both levels of increased RRS caused poor trending ability for Cdyn(ECAiOV), whereas the same effect was only observed for Cdyn(NM3) at R2. CONCLUSIONS AND CLINICAL RELEVANCE: In the presence of increased RRS, Cdyn estimated by the NM3 monitor presented better capability to distinguish between changes in RRS from changes in respiratory system compliance.

Evaluation of short-term risk factors associated with dehiscence and death following full-thickness incisions of the large intestine in cats: 84 cases (1993-2015).

OBJECTIVE: To evaluate short-term risk factors associated with dehiscence and death in cats undergoing full-thickness large intestinal incisions. ANIMALS: 84 client-owned cats that had undergone full-thickness large intestinal incisions and for which information regarding outcome through postoperative day 7 was available. PROCEDURES: Medical records from 4 veterinary teaching hospitals were reviewed. For cats that met the inclusion criteria, signalment, history, laboratory test results, surgical and medical procedures, perioperative complications, and outcome were analyzed. A Fisher exact or Wilcoxon rank sum test was used to identify individual variables associated with dehiscence of intestinal incisions or patient nonsurvival to hospital discharge or both. RESULTS: 84 cats met the inclusion criteria. The overall dehiscence and survival to hospital discharge rates were 8.3% (7/84 cats) and 94% (79/84 cats), respectively. Factors associated with dehiscence and nonsurvival to hospital discharge included presence of band neutrophils, performance of partial colectomy with colonic resection and anastomosis, administration of blood products, postoperative cardiopulmonary arrest, and incisional inflammation or infection. Factors associated with nonsurvival to hospital discharge only included low serum globulin concentration, repair of colonic trauma or dehiscence, and postoperative colonic dehiscence. Factors associated with dehiscence only included hypoalbuminemia, renal dysfunction, administration of blood products or > 2 classes of antimicrobials, and intra-abdominal fecal contamination. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that intestinal dehiscence and mortality rates associated with large intestinal incisions in cats may be higher than previously proposed, although the risk of either outcome was still low. Factors suggestive of systemic illness were associated with colonic dehiscence or death, and focused prospective studies of risk factors are warranted.

Factors associated with postobstructive diuresis following decompressive surgery with placement of ureteral stents or subcutaneous ureteral bypass systems for treatment of ureteral obstruction in cats: 37 cases (2010-2014).

OBJECTIVE: To describe postobstructive diuresis (POD) in cats undergoing surgical placement of ureteral stents or subcutaneous ureteral bypass systems for treatment of ureteral obstruction in cats and to identify factors associated with duration and maximum severity of POD. DESIGN: Retrospective case series. ANIMALS: 37 client-owned cats with ureteral obstruction treated between August 2010 and December 2014. PROCEDURES: Medical records were reviewed, and data extracted included signalment, history, results from physical examinations and clinical laboratory analyses, treatment, urine output, and outcome. Data were evaluated to identify factors associated with POD duration and maximum severity, alone or in combination. RESULTS: Serum concentrations of creatinine, potassium, phosphorus, and BUN before surgery positively correlated with duration and maximum severity of POD. Absolute changes in serum concentrations of creatinine, potassium, and BUN from before surgery to after surgery positively correlated with POD duration. Cats with anuria before surgery had longer POD than did other cats; however, there was no difference in POD duration or maximum severity with unilateral versus bilateral ureteral obstruction. Thirty-four of 37 (92%) cats survived to hospital discharge, which was not associated with whether ureteral obstruction was unilateral or bilateral. Azotemia resolved in 17 of the 34 (50%) cats that survived to hospital discharge. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study indicated that several factors were associated with POD duration and maximum severity, alone or in combination, and that with intensive management of fluid and electrolyte derangements, regardless of the extent of the original azotemia, a high percentage of cats survived to hospital discharge.

Complications and outcomes associated with unilateral thyroidectomy in dogs with naturally occurring thyroid tumors: 156 cases (2003-2015).

OBJECTIVE: To describe complications and outcomes of dogs undergoing unilateral thyroidectomy for the treatment of thyroid tumors. ANIMALS: 156 dogs undergoing unilateral thyroidectomy for a naturally occurring thyroid tumor. PROCEDURES: Dogs that underwent a unilateral thyroidectomy in 2003 through 2015 were included in a multi-institutional retrospective study. For each dog, information gathered through evaluation of electronic and paper records included perioperative complications, short-term outcome (survival to discharge from the hospital vs nonsurvival), and long-term outcome (survival time). RESULTS: In the perioperative period, complications occurred in 31 of the 156 (19.9%) dogs; hemorrhage was the most common intraoperative complication (12 [7.7%] dogs). Five of 156 (3.2%) dogs received a blood transfusion; these 5 dogs were among the 12 dogs that had hemorrhage listed as an intraoperative complication. Immediately after surgery, the most common complication was aspiration pneumonia (5 [3.2%] dogs). One hundred fifty-three of 156 (98.1%) dogs that underwent unilateral thyroidectomy survived to discharge from the hospital. One hundred-thirteen dogs were lost to follow-up; from the available data, the median survival time was 911 days (95% confidence interval, 704 to 1,466 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that unilateral thyroidectomy in dogs with a naturally occurring thyroid tumor was associated with a perioperative mortality rate of 1.9% and a complication rate of 19.9% and that hemorrhage and aspiration pneumonia were the most common complications. Long-term survival of dogs undergoing unilateral thyroidectomy for the treatment of thyroid tumors was not uncommon.

Evaluation of short-term outcomes and potential risk factors for death and intestinal dehiscence following full-thickness large intestinal incisions in dogs.

OBJECTIVE: To determine complication rates for dogs in which full-thickness large intestinal incisions were performed, assess potential risk factors for death during hospitalization and for intestinal dehiscence following these surgeries, and report short-term mortality rates for these patients. ANIMALS: 90 dogs. PROCEDURES: Medical records of 4 veterinary referral hospitals were reviewed to identify dogs that underwent large intestinal surgery requiring full-thickness incisions. Signalment, history, clinicopathologic data, medical treatments, surgical procedures, complications, and outcomes were recorded. Descriptive statistics were calculated; data were analyzed for association with survival to discharge (with logistic regression analysis) and postoperative intestinal dehiscence (with Fisher exact or Wilcoxon rank sum tests). RESULTS: Overall 7-day postoperative intestinal dehiscence and mortality rates were 9 of 90 (10%) and 15 of 90 (17%). Dogs with preoperative anorexia, hypoglycemia, or neutrophils with toxic changes and those that received preoperative antimicrobial treatment had greater odds of death than did dogs without these findings. Preexisting colon trauma or dehiscence, preexisting peritonitis, administration of blood products, administration of > 2 classes of antimicrobials, positive microbial culture results for a surgical sample, and open abdominal management of peritonitis after surgery were associated with development of intestinal dehiscence. Five of 9 dogs with intestinal dehiscence died or were euthanized. CONCLUSIONS AND CLINICAL RELEVANCE: Factors associated with failure to survive to discharge were considered suggestive of sepsis. Results suggested the dehiscence rate for full-thickness large intestinal incisions may not be as high as previously reported, but several factors may influence this outcome and larger, longer-term studies are needed to confirm these findings.