Gareth J. Buckley

Massive transfusion and surgical management of iatrogenic aortic laceration associated with cystocentesis in a dog

CASE DESCRIPTION A 4-year-old 29-kg (63.8-lb) spayed female Husky crossbred was referred for emergency treatment because of catastrophic hemorrhagic shock following attempts at cystocentesis for investigation of suspected urinary tract infection. CLINICAL FINDINGS On arrival at the hospital, clinicopathologic assessments revealed rapidly decreasing PCV and worsening hypoproteinemia, compared with findings immediately prior to referral. The dog had severe hyperlactemia. Ultrasonography revealed the presence of free fluid in the abdomen; the fluid appeared to be blood (determined via abdominocentesis). TREATMENT AND OUTCOME Urgent surgical exploration was undertaken. Two small lacerations in the ventral aspect of the abdominal aorta just dorsal to the bladder were identified and repaired. Multiple transfusions of packed RBCs (5 units) and fresh frozen plasma (3 units) were administered, and autotransfusion of blood (1.2 L) from the abdomen was performed. The dog recovered well from surgery and anesthesia, but developed signs of severe pain and swelling of both hind limbs, which were attributed to reperfusion injury following aortic occlusion during surgery. Treatment included administration of S-adenosylmethionine (23 mg/kg [10.5 mg/lb], PO, q 24 h) and analgesia; 5 days after surgery, the hind limb problems had resolved and treatments were discontinued. CLINICAL RELEVANCE In the dog of this report, aortic laceration secondary to cystocentesis was successfully treated with a combination of surgery and massive transfusion; the development of reperfusion injury was an interesting and reversible complication of surgery. The possibility of damage to intra-abdominal structures should be investigated if a dog becomes acutely ill after cystocentesis.

Use of IV Lipid Emulsion for Treatment of Ivermectin Toxicosis in a Cat

Ivermectin toxicosis in cats is infrequently reported. IV lipid emulsion (ILE) is a novel treatment in veterinary medicine that has been used for amelioration of adverse effects seen with multiple lipid soluble compounds. Previously, ILE has been investigated in experimental models with rats, rabbits, pigs, and dogs, mainly for resuscitation of cardiopulmonary arrest and treatment of hypotension due to local anesthetic drug overdose. There are few case reports in veterinary medicine of using ILE for drug toxicity. Only one feline case has been reported, with IV lipids used for treatment of lidocaine toxicity. This report describes a case of ivermectin toxicosis in a 1 yr old domestic shorthair that was safely and successfully treated using ILE.

RECOVER evidence and knowledge gap analysis on veterinary CPR. Part 4: Advanced life support

Objective To systematically evaluate the evidence of the effect of advanced life support techniques on outcome in veterinary cardiopulmonary resuscitation (CPR) and to outline knowledge gaps. Design Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. Setting Academia, referral practice, and general practice Results Sixteen population, intervention, control group, outcome questions were evaluated to determine if recommendations could be made concerning drug therapy, including vasopressors, vagolytics, corticosteroids, reversal agents, buffer therapy, and correction of electrolyte disturbances. Electrical defibrillation strategies as well as other advanced interventions such as open-chest CPR, impedance threshold devices, and special considerations regarding anesthesia-related cardiopulmonary arrest (CPA) were also investigated. Conclusions There is strong evidence supporting the use of standard-dose (0.01 mg/kg) epinephrine in CPR, as well as early electrical defibrillation for animals experiencing CPA due to ventricular fibrillation or pulseless ventricular tachycardia, preferentially using a biphasic defibrillator. For CPA due to certain causes and with the availability of advanced postcardiac arrest support, open chest CPR is preferred. Many knowledge gaps regarding other pharmacologic and advanced therapies were identified, and further studies are recommended to better systematically address these questions.OBJECTIVE To systematically evaluate the evidence of the effect of advanced life support techniques on outcome in veterinary cardiopulmonary resuscitation (CPR) and to outline knowledge gaps. DESIGN Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. SETTING Academia, referral practice, and general practice RESULTS Sixteen population, intervention, control group, outcome questions were evaluated to determine if recommendations could be made concerning drug therapy, including vasopressors, vagolytics, corticosteroids, reversal agents, buffer therapy, and correction of electrolyte disturbances. Electrical defibrillation strategies as well as other advanced interventions such as open-chest CPR, impedance threshold devices, and special considerations regarding anesthesia-related cardiopulmonary arrest (CPA) were also investigated. CONCLUSIONS There is strong evidence supporting the use of standard-dose (0.01 mg/kg) epinephrine in CPR, as well as early electrical defibrillation for animals experiencing CPA due to ventricular fibrillation or pulseless ventricular tachycardia, preferentially using a biphasic defibrillator. For CPA due to certain causes and with the availability of advanced postcardiac arrest support, open chest CPR is preferred. Many knowledge gaps regarding other pharmacologic and advanced therapies were identified, and further studies are recommended to better systematically address these questions.

Low tidal volume ventilation in healthy dogs.

Objective To determine if low tidal volume (VT) ventilation is associated with the development of respiratory acidosis and changes in lung function in healthy dogs. Design Randomized prospective experimental cross-over study. Setting Pulmonary function laboratory at a university teaching hospital. Animals Five healthy Beagle dogs. Interventions Dogs were anesthetized and randomly mechanically ventilated with VT of 6, 8, 10, 12, and 15 mL/kg while maintaining a constant minute volume. Measurements and Main Results Arterial blood gases and pulmonary mechanics were collected after 15 minutes of equilibration at each VT. Repeated measures ANOVA was used to determine the effect of VT with a P-value of <0.05 considered significant, and a Pearson product moment was used to determine correlation between VT and pH and PaCO2. VT had a significant effect on PaCO2 (P < 0.001) and on pH (P < 0.001) with lower VT being associated with higher PaCO2 and lower pH. There was a strong correlation between VT and PaCO2 (r = –0.87) and VT and pH (r = 0.83). Increased airway pressures and pulmonary compliance were associated with increasing VT. Conclusions There is a predictable decrease in the pH, decrease in airway pressure, decrease in compliance, and increase in the PaCO2 associated with lower VT. Low VT ventilation is well tolerated in healthy dogs; the role of low VT ventilation in dogs with acute lung injury/acute respiratory distress syndrome as well as the influence of positive end expiratory pressure requires further evaluation.OBJECTIVE To determine if low tidal volume (V(T) ) ventilation is associated with the development of respiratory acidosis and changes in lung function in healthy dogs. DESIGN Randomized prospective experimental cross-over study. SETTING Pulmonary function laboratory at a university teaching hospital. ANIMALS Five healthy Beagle dogs. INTERVENTIONS Dogs were anesthetized and randomly mechanically ventilated with V(T) of 6, 8, 10, 12, and 15 mL/kg while maintaining a constant minute volume. MEASUREMENTS AND MAIN RESULTS Arterial blood gases and pulmonary mechanics were collected after 15 minutes of equilibration at each V(T). Repeated measures ANOVA was used to determine the effect of V(T) with a P-value of <0.05 considered significant, and a Pearson product moment was used to determine correlation between V(T) and pH and PaCO(2). V(T) had a significant effect on PaCO(2) (P < 0.001) and on pH (P < 0.001) with lower V(T) being associated with higher PaCO(2) and lower pH. There was a strong correlation between V(T) and PaCO(2) (r = -0.87) and V(T) and pH (r = 0.83). Increased airway pressures and pulmonary compliance were associated with increasing V(T). CONCLUSIONS There is a predictable decrease in the pH, decrease in airway pressure, decrease in compliance, and increase in the PaCO(2) associated with lower V(T). Low V(T) ventilation is well tolerated in healthy dogs; the role of low V(T) ventilation in dogs with acute lung injury/acute respiratory distress syndrome as well as the influence of positive end expiratory pressure requires further evaluation.

Interpretation of canine and feline blood smears by emergency room personnel

BACKGROUND Interpretation of blood smears is commonly used to provide rapid laboratory evaluation of animals in veterinary emergency practice, but the accuracy of results of blood smear interpretation by emergency room personnel (ERP) compared with evaluation by trained veterinary clinical pathology personnel is unknown. OBJECTIVE The goal of this study was to compare blood smear evaluation by ERP with that of clinical pathology personnel. METHODS All animals that had a CBC determined by a diagnostic laboratory and had blood smears evaluated by personnel at the Foster Hospital for Small Animals Emergency Room between September 2008 and July 2009 were eligible for study inclusion. ERP who evaluated blood smears completed standardized forms with estimates of the WBC and platelet counts and evaluation of RBC and WBC morphology. Results from point-of-care assessment were compared with automated or manual results reported by the veterinary diagnostic laboratory. RESULTS One hundred and fifty-five blood smears were evaluated. There was moderate agreement (κ value, 0.63; 95% confidence interval [CI]: 0.52, 0.74) between estimated platelet counts by ERP and automated counts. Poor agreement was found between estimated WBC counts by ERP and automated counts (κ value, 0.48; 95% CI: 0.37, 0.60). Specific abnormalities with a high likelihood of clinical significance, eg, toxic change, nucleated RBCs, spherocytes, hemoparasites, and lymphoblasts, were not predictably identified by ERP. CONCLUSIONS ERP interpretation of canine and feline blood smears should be used cautiously and should not replace evaluation by a veterinary diagnostic laboratory.

The effect of using an impedance threshold device on hemodynamic parameters during cardiopulmonary resuscitation in dogs

OBJECTIVE To investigate the hemodynamic effects following the use of an impedance threshold device (ITD) in a canine model of cardiopulmonary arrest. DESIGN Experimental, randomized crossover study. SETTING Cardiovascular research laboratory at a university veterinary center. ANIMALS Eight purpose bred beagle dogs. INTERVENTIONS Dogs were anesthetized and instrumented for the measurement of right atrial pressure , systolic blood pressure, mean blood pressure, and diastolic arterial blood pressure, end-tidal CO(2) , and carotid blood flow (CBF). CBF was determined via ultrasonic flow probe placed around the carotid artery. Animals were taking part in an unassociated terminal study and following subsequent euthanasia with pentobarbital, standardized cardiopulmonary resuscitation (CPR) was performed with an impedance threshold device attached (ITD-CPR group) and without (S-CPR group). Order of treatment was randomized. MEASUREMENTS AND MAIN RESULTS ITD group had increased CBF, coronary perfusion pressure, and a decrease in right atrial diastolic pressure. No differences in end-tidal CO(2) , diastolic arterial blood pressure, mean blood pressure, or systolic blood pressure were seen. Return of spontaneous circulation was not observed in any of the animals CONCLUSIONS Use of the ITD resulted in favorable changes in hemodynamic parameters in dogs undergoing CPR. The ITD may be a useful adjunct during CPR in dogs and warrants clinical evaluation.Objective To investigate the hemodynamic effects following the use of an impedance threshold device (ITD) in a canine model of cardiopulmonary arrest. Design Experimental, randomized crossover study. Setting Cardiovascular research laboratory at a university veterinary center. Animals Eight purpose bred beagle dogs. Interventions Dogs were anesthetized and instrumented for the measurement of right atrial pressure , systolic blood pressure, mean blood pressure, and diastolic arterial blood pressure, end-tidal CO2, and carotid blood flow (CBF). CBF was determined via ultrasonic flow probe placed around the carotid artery. Animals were taking part in an unassociated terminal study and following subsequent euthanasia with pentobarbital, standardized cardiopulmonary resuscitation (CPR) was performed with an impedance threshold device attached (ITD-CPR group) and without (S-CPR group). Order of treatment was randomized. Measurements and Main Results ITD group had increased CBF, coronary perfusion pressure, and a decrease in right atrial diastolic pressure. No differences in end-tidal CO2, diastolic arterial blood pressure, mean blood pressure, or systolic blood pressure were seen. Return of spontaneous circulation was not observed in any of the animals Conclusions Use of the ITD resulted in favorable changes in hemodynamic parameters in dogs undergoing CPR. The ITD may be a useful adjunct during CPR in dogs and warrants clinical evaluation.

Cardiopulmonary effects of a new inspiratory impedance threshold device in acute hemorrhagic shock in dogs

OBJECTIVE To compare cardiovascular and respiratory effects of an inspiratory impedance threshold device (ITD) in dogs before and after induction of acute hemorrhagic shock. STUDY DESIGN Prospective experimental randomized study. ANIMALS Eight healthy adult dogs. METHODS Dogs were anesthetized and maintained on spontaneous ventilation. Tidal volume (V(T)), systolic, mean and diastolic arterial blood pressure (SAP, MAP, DAP), central venous pressure (CVP), gastric P(CO2) (GBF) as an indicator of gastric perfusion, cardiac index (CI), systemic vascular resistance (SVR), oxygen delivery (DO(2)), and plasma lactate were monitored. To monitor respiratory compliance (RC) and respiratory resistance (ResR), animals were briefly placed on mechanical ventilation. Dogs were studied under 4 different conditions: (1) baseline (euvolemic state) (MAP > 60 mm Hg) with and without the ITD and (2) acute hemorrhagic shock (hypovolemic state) (target MAP of 40 mm Hg) with and without ITD. These 4 conditions were performed during one anesthetic period, allowing time for stabilization of parameters for each condition. Data were analyzed by ANOVA for repeated measure mixed models. RESULTS No cardiovascular changes were detected between groups with and without use of ITD during euvolemic states. During acute hemorrhagic hypovolemic state, CI and DO(2) were higher with the ITD (2.9 ± 0.6 L/min/m(2)) and (326.5 ± 86.8 mL/min) compared with no ITD (1.8 ± 0.6 L/min/m(2)) and (191.3 ± 58.1 mL/min), respectively. The use of ITD during hypovolemia also increased SAP and MAP. There was an increase in ResR and decreased RC with the ITD in both euvolemic and hypovolemic states. CONCLUSION AND CLINICAL RELEVANCE The use of an ITD in dogs during acute hemorrhagic hypovolemic shock improved cardiovascular parameters but had negative effects on RC and ResR.

Diagnostic usefulness of laparoscopy versus exploratory laparotomy for dogs with suspected gastrointestinal obstruction

OBJECTIVE To evaluate the feasibility of laparoscopy versus exploratory laparotomy for the diagnosis of specific lesions in dogs with suspected gastrointestinal obstruction. DESIGN Controlled trial. ANIMALS 16 client-owned dogs with physical and radiographic findings consistent with gastrointestinal obstruction. PROCEDURES Single-incision laparoscopy with intracorporeal and extracorporeal examination of the gastrointestinal tract was performed by 1 surgeon. Immediately afterward, exploratory laparotomy was performed by a second surgeon. Accessibility and gross appearance of organs, surgical diagnoses, incision lengths, procedure duration, and complications were compared between diagnostic techniques. RESULTS Mean (95% confidence interval) incision length was 4.9 cm (3.9 to 5.9 cm) for laparoscopy and 16.4 cm (14.0 to 18.7 cm) for exploratory laparotomy. Mean (95% confidence interval) procedure duration was 36.8 minutes (31.6 to 41.2 minutes) and 12.8 minutes (11.4 to 14.3 minutes), respectively. Diagnoses of the cause of obstruction were the same with both methods. In 13 dogs, the laparoscopic examination was successfully completed, and in the other 3, it was incomplete. In 4 dogs in which laparoscopy was successful, conversion to exploratory laparotomy or considerable extension of the laparoscopic incision would have been required to allow subsequent surgical treatment of identified lesions. No dogs developed major complications, and minor complication rates were similar between procedures. CONCLUSIONS AND CLINICAL RELEVANCE Laparoscopy was feasible and clinically applicable in dogs with suspected gastrointestinal obstruction. Careful patient selection and liberal criteria for conversion to an open surgical approach are recommended when laparoscopy is considered for the diagnosis of gastrointestinal lesions in dogs.

Temporary percutaneous T-fastener gastropexy and continuous decompressive gastrostomy in dogs with experimentally induced gastric dilatation

OBJECTIVE To evaluate a percutaneous, continuous gastric decompression technique for dogs involving a temporary T-fastener gastropexy and self-retaining decompression catheter. ANIMALS 6 healthy male large-breed dogs. PROCEDURES Dogs were anesthetized and positioned in dorsal recumbency with slight left-lateral obliquity. The gastric lumen was insufflated endoscopically until tympany was evident. Three T-fasteners were placed percutaneously into the gastric lumen via the right lateral aspect of the abdomen, caudal to the 13th rib and lateral to the rectus abdominis muscle. Through the center of the T-fasteners, a 5F locking pigtail catheter was inserted into the gastric lumen and attached to a device measuring gas outflow and intragastric pressure. The stomach was insufflated to 23 mm Hg, air was allowed to passively drain from the catheter until intraluminal pressure reached 5 mm Hg for 3 cycles, and the catheter was removed. Dogs were hospitalized and monitored for 72 hours. RESULTS Mean ± SD catheter placement time was 3.3 ± 0.5 minutes. Mean intervals from catheter placement to a ≥ 50% decrease in intragastric pressure and to ≤ 6 mm Hg were 2.1 ± 1.3 minutes and 8.4 ± 5.1 minutes, respectively. After catheter removal, no gas or fluid leakage at the catheter site was visible laparoscopically or endoscopically. All dogs were clinically normal 72 hours after surgery. CONCLUSIONS AND CLINICAL RELEVANCE The described technique was performed rapidly and provided continuous gastric decompression with no evidence of postoperative leakage in healthy dogs. Investigation is warranted to evaluate its effectiveness in dogs with gastric dilatation-volvulus.

Clearance of plasma ivermectin with single pass lipid dialysis in 2 dogs: Lipid dialysis for ivermectin toxicosis

OBJECTIVE To describe the use of single pass lipid dialysis (SPLD) for treatment of ivermectin toxicosis in 2 Australian Shepherd dogs with the ABCB1-1Δ gene mutation. CASE SERIES SUMMARY Two Australian Shepherd dogs were presented for treatment of ivermectin toxicosis. Dogs were initially treated with intravenous lipid emulsion and supportive care, without improvement of clinical signs. They both developed respiratory paralysis and required mechanical ventilation. In order to increase the clearance of circulating ivermectin, SPLD was performed using dialysate containing 5% lipid. Blood samples were obtained immediately before and after dialysis and analyzed for serum ivermectin concentration. Ivermectin reduction ratio was calculated at 29% and 39% for each dog, respectively. When compared to intrinsic total body ivermectin clearance, only the second dog had a relative improvement of plasma clearance following SPLD. Both dogs were confirmed to be homozygous for ABCB1-1Δ gene mutations. Both dogs remained ventilator dependent for several days and ultimately made a full recovery. NEW OR UNIQUE INFORMATION PROVIDED SPLD may be an adjunctive detoxification strategy for highly lipophilic toxins such as ivermectin.Objective To describe the use of single pass lipid dialysis (SPLD) for treatment of ivermectin toxicosis in 2 Australian Shepherd dogs with the ABCB1-1Δ gene mutation. Case Series Summary Two Australian Shepherd dogs were presented for treatment of ivermectin toxicosis. Dogs were initially treated with intravenous lipid emulsion and supportive care, without improvement of clinical signs. They both developed respiratory paralysis and required mechanical ventilation. In order to increase the clearance of circulating ivermectin, SPLD was performed using dialysate containing 5% lipid. Blood samples were obtained immediately before and after dialysis and analyzed for serum ivermectin concentration. Ivermectin reduction ratio was calculated at 29% and 39% for each dog, respectively. When compared to intrinsic total body ivermectin clearance, only the second dog had a relative improvement of plasma clearance following SPLD. Both dogs were confirmed to be homozygous for ABCB1-1Δ gene mutations. Both dogs remained ventilator dependent for several days and ultimately made a full recovery. New or Unique Information Provided SPLD may be an adjunctive detoxification strategy for highly lipophilic toxins such as ivermectin.