Objective—To characterize halothane and sevoflurane
anesthesia in spontaneously breathing rats.
Animals—16 healthy male Sprague-Dawley rats.
Procedure—8 rats were anesthetized with halothane
and 8 with sevoflurane. Minimum alveolar concentration
(MAC) was determined. Variables were recorded
at anesthetic concentrations of 0.8, 1.0, 1.25, and 1.5
times the MAC of halothane and 1.0, 1.25, 1.5, and
1.75 times the MAC of sevoflurane.
Results—Mean (± SEM) MAC for halothane was 1.02
± 0.02% and for sevoflurane was 2.99 ± 0.19%. As
sevoflurane dose increased from 1.0 to 1.75 MAC,
mean arterial pressure (MAP) decreased from 103.1 ±
5.3 to 67.9 ± 4.6 mm Hg, and PaCO2 increased from
58.8 ± 3.1 to 92.2 ± 9.2 mm Hg. As halothane dose
increased from 0.8 to 1.5 MAC, MAP decreased from
99 ± 6.2 to 69.8 ± 4.5 mm Hg, and PaCO2 increased
from 59.1 ± 2.1 to 75.9 ± 5.2 mm Hg. Respiratory rate
decreased in a dose-dependent fashion from 88.5 ±
4.5 to 58.5 ± 2.7 breaths/min during halothane anesthesia
and from 42.3 ± 1.8 to 30.5 ± 4.5 breaths/min
during sevoflurane anesthesia. Both groups of rats
had an increase in eyelid and pupillary aperture with
an increase in anesthetic dose.
Conclusions and Clinical Relevance—An increase
in PaCO2 and a decrease in MAP are clinical indicators
of an increasing halothane and sevoflurane dose in
unstimulated spontaneously breathing rats.
Increases in eyelid aperture and pupil diameter are
reliable signs of increasing depth of halothane and
sevoflurane anesthesia. Decreasing respiratory rate is
a clinical indicator of an increasing dose of halothane.
(Am J Vet Res 2003;64:470–474)
Case Description—An 8-month-old castrated male mixed-breed dog was evaluated because of hematuria, stranguria, and dysuria of approximately 2 weeks’ duration that developed immediately following elective castration.
Clinical Findings—Results of physical examination, ultrasonography, retrograde double-contrast cystourethrography, and urethroscopy were consistent with a traumatic urethral stricture immediately proximal to the os penis resulting in a partial obstruction of urine outflow. Results of ultrasonographic examination of abdominal organs were considered normal. Digital radiography revealed no evidence of calculi.
Treatment and Outcome—Balloon dilation of the urethral stricture was performed and was followed by 2 bougienage procedures during the subsequent 2 weeks when clinical signs returned. The owners declined scrotal urethrostomy, and a self-expanding, covered nitinol stent was placed approximately 3 weeks after the initial evaluation, resulting in amelioration of clinical signs. Results of follow-up urethroscopy and contrast cystourethrography 1 year after stent placement revealed a statically positioned, patent urethral stent, although a small number of polypoid mucosal structures were identified distal to the stent and 1 small structure consistent with tissue ingrowth into the stent was identified.
Clinical Relevance—Placement of a covered nitinol stent resulted in long-term resolution of clinical signs associated with traumatic stricture of the penile urethra in this young dog. Because the os penis in dogs limits radial expansion of the urethra, its presence may limit the use of stents in this location.
Case Description—3 dogs (9 to 12 years old) were evaluated because of recurrent pleural effusion that was refractory to treatment of the underlying cause.
Clinical Findings—Dogs were evaluated because of cough, dyspnea, tachypnea, or lethargy or a combination of these clinical signs. Radiography, ultrasonography, or thoracocentesis were used to confirm the presence of pleural fluid in each dog. A neoplastic cause of pleural effusion was confirmed in 2 dogs. In 1 dog, fasciitis of the mediastinum and the left parietal pleura was diagnosed, with no evidence of neoplasia.
Treatment and Outcome—Each dog was anesthestized, and thoracotomy was performed with manual perforation of the mediastinum. Permanent, subcutaneously placed vascular access ports were attached to intrathoracic, Jackson-Pratt drain tubing for repeated drainage of pleural fluid. Drains were used successfully in the 3 dogs for periods of 6 weeks, 11 weeks, and > 3 years.
Clinical Relevance—Findings suggest that subcutaneous vascular access ports attached to intrathoracic drain tubing may be an effective way to remove recurrent pleural effusion in dogs.
Case Description—An 8-week-old female domestic shorthair cat was treated for patent ductus arteriosus (PDA) with surgical ligation. Seven weeks postoperatively, the cat was evaluated because of increased upper respiratory noise, inspiratory stridor, wheezing, and episodes of intermittent open-mouth breathing that had developed 1 week following the surgical ligation.
Clinical Findings—The cat was sedated, and examination of the larynx revealed left-sided laryngeal paralysis.
Treatment and Outcome—At the time left-sided laryngeal paralysis was diagnosed, the clinical signs of laryngeal dysfunction were not considered severe enough to warrant surgical intervention. No treatment was administered, and the owner monitored the cat for respiratory distress and worsening of clinical signs for an additional 5 months. During those 5 months, the clinical signs improved but persisted. Seven months after PDA ligation, the cat was again sedated and the larynx examined. The examination revealed persistent left arytenoid dysfunction, which was believed to be the result of permanent damage to the recurrent laryngeal nerve that was sustained during the surgical ligation of the PDA. The owner was counseled about surgical and medical treatment options for laryngeal paralysis but elected to forego treatment at that time.
Clinical Relevance—Unilateral laryngeal paralysis caused by iatrogenic damage to the recurrent laryngeal nerve is a potential complication subsequent to surgical ligation of a PDA. The frequency of iatrogenically induced laryngeal paralysis is likely underestimated in small animal patients. Laryngoscopy should be performed in any small animal with a history of PDA attenuation and clinical signs of respiratory tract disease.
Objective—To determine survival times in dogs with
right atrial hemangiosarcoma treated by means of
pericardectomy and tumor resection, with or without
adjuvant chemotherapy, and identify complications
associated with treatment.
Procedure—Dogs were included only if the diagnosis
was confirmed histologically.
Results—The most common initial complaints included
acute collapse (8 [35%] dogs), anorexia or inappetence
(8 [35%]), and lethargy (8 [35%]). The most common
physical examination abnormalities included muffled
heart sounds (12 [52%] dogs), tachycardia (7
[30%]), and weak pulses (7 [30%]). Postoperative complications
developed in 12 (52%) dogs; however, most
complications were minor. Twenty (87%) dogs were
discharged from the hospital. Survival time was significantly
longer in the 8 dogs that received adjuvant
chemotherapy (mean, 164 days; median, 175 days)
than in the 15 dogs that did not receive chemotherapy
(mean, 46 days; median, 42 days). Dogs that received
chemotherapy were significantly younger and had significantly
lower WBC counts than did dogs that did not
Conclusions and Clinical Relevance—Results suggested
that in dogs with right atrial hemangiosarcoma,
surgical resection of the tumor was associated with a
low complication rate and complications that did arise
typically were minor. In addition, use of adjuvant
chemotherapy following resection was associated with
significantly longer survival times, compared with resection
alone. (J Am Vet Med Assoc 2005;226:575–579)
Objective—To characterize the clinical features and outcome of cats treated for patent ductus arteriosus (PDA) with attenuation (extravascular or intravascular) versus medical treatment only.
Design—Retrospective case series.
Animals—28 client-owned cats with congenital PDA.
Procedures—Medical records for cats with PDA diagnosed by means of echocardiography were reviewed. Data retrieved included signalment; history; clinical signs; results of physical examination, ECG, echocardiography, and thoracic radiography; response to medical management if attempted; type of attenuation procedure if attempted (surgical or intravascular); procedural details; intraoperative and postoperative (≤ 2 weeks) complications; and long-term (> 2 weeks) complications. Follow-up was obtained from medical records and via telephone interviews.
Results—All 28 cats were referred for evaluation of a cardiac murmur, but 17 of 26 (65%) for which initial clinical signs were available did not have overt signs at initial evaluation. Multiple congenital cardiac defects were identified in 6 of 23 (26%) cats. Seventeen of 26 (65%) cats were documented as treated with 1 or more vascular attenuation procedures; vascular attenuation was not attempted in 11 cats receiving an angiotensin-converting enzyme inhibitor or loop diuretic (n = 2) or no medical treatment (9). Surgical ligation was successful in 11 of 15 cats, and coil embolization was successful in 2 cats. Procedural or postoperative complications included death (n = 2), left-sided laryngeal paralysis (2), voice change (1), fever (1), hemorrhage (4), and chylothorax (1). Long-term follow-up was available for 16 of 28 (57%) cats. Three of 4 cats that did not undergo surgical attenuation died of cardiac-related disease.
Conclusions and Clinical Relevance—Results suggested that PDA occurs rarely in cats, and clinical signs and diagnostic findings were consistent with those previously reported for dogs. Surgical versus nonsurgical treatment did not result in a significant difference in life expectancy in this small cohort. Evaluation of laryngeal function after surgical ligation is recommended. Further study of the outcome associated with various treatment options in a larger population of patients is recommended.
Objective—To describe the technique and evaluate the outcome of laparoscopic treatment of ovarian remnant syndrome (ORS) in dogs and cats.
Design—Retrospective case series.
Animals—7 client-owned dogs and cats.
Procedures—Medical records of dogs and cats with ORS that were treated laparoscopically at 3 large veterinary teaching hospitals were reviewed. Laparoscopic ovarian remnant resection was performed by means of either a 3-port or single-port technique with the patient in dorsal recumbency. The area caudal to both kidneys was thoroughly inspected for evidence of ovarian tissue by tilting the patient laterally. Any ovarian remnant tissue in these areas was resected with a bipolar vessel sealer.
Results—5 female dogs and 2 female cats that had previously undergone ovariectomy or ovariohysterectomy were included in the study. Six procedures were performed with a standard 3-port technique, and 1 was performed with a single-port technique. Median surgery time was 90 minutes (range, 50 to 150 minutes). No patient required conversion to laparotomy. Six of the 7 patients had complete resolution of clinical signs after surgery. One patient underwent laparotomy 7 weeks after surgery for management of stump pyometra, but no further ovarian tissue was detected.
Conclusions and Clinical Relevance—Laparoscopic management of ORS in this cohort of dogs and cats was associated with minimal morbidity. Laparoscopic treatment of ORS in dogs and cats may be recommended for appropriately selected patients.
OBJECTIVE To evaluate the effect of intra-abdominal pressure (IAP) on morphology and compliance of the lower esophageal sphincter (LES) by use of impedance planimetry in healthy dogs and to quantify the effect of changes in IAP.
ANIMALS 7 healthy, purpose-bred sexually intact male hound-cross dogs.
PROCEDURES Dogs were anesthetized, and cross-sectional area (CSA), minimal diameter (MD), LES length, LES volume, and distensibility index (DI) of the LES were evaluated by use of an endoscopic functional luminal imaging probe. For each dog, measurements were obtained before (baseline) and after creation of a pneumoperitoneum at an IAP of 4, 8, and 15 mm Hg. Order of the IAPs was determined by use of a randomization software program.
RESULTS CSA and MD at 4 and 8 mm Hg were not significantly different from baseline measurements; however, CSA and MD at 15 mm Hg were both significantly greater than baseline measurements. The LES length and LES volume did not differ significantly from baseline measurements at any IAP. The DI differed inconsistently from the baseline measurement but was not substantially affected by IAP.
CONCLUSIONS AND CLINICAL RELEVANCE Pneumoperitoneum created with an IAP of 4 or 8 mm Hg did not significantly alter LES morphology in healthy dogs. Pneumoperitoneum at an IAP of 15 mm Hg caused a significant increase in CSA and MD of the LES. Compliance of the LES as measured by the DI was not greatly altered by pneumoperitoneum at an IAP of up to 15 mm Hg.