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1.
The haemodynamic and metabolic effects of caudal vena cava occlusion were evaluated in six normal anaesthetised dogs. Each animal underwent a single eight minute episode of caudal vena cava occlusion. The procedure was well tolerated by all the dogs. Systolic arterial pressure was reduced by 62 +/- 5 per cent and the heart rate increased by 11 +/- 3 per cent. There was rapid haemodynamic recovery after the release of occlusion, all cardiovascular parameters returning to normal spontaneously within five minutes. Caudal vena cava occlusion is therefore safe for periods of up to eight minutes in normal dogs. This technique allows repair of caudal vena caval lesions without necessitating systemic heparinisation and the use of cavoatrial conduits.  相似文献   

2.
Twenty-two dogs with congenital single portosystemic shunts were treated by partial or complete ligation of the shunts. Intraoperative portal pressures before and after shunt ligation, and central venous pressures measured after 3 minutes of temporary shunt occlusion, were evaluated prospectively. Portal pressures after ligation, increases in portal pressure above baseline values, and decreases in central venous pressure during temporary occlusion were significantly greater in dogs that underwent partial portosystemic shunt ligation and in dogs that developed postoperative complications. Absence of arborizing intrahepatic vasculature in intraoperative mesenteric portograms did not indicate whether partial or complete shunt attenuation could be performed safely, but it was correlated with greater occurrence of post-operative complications.  相似文献   

3.
Oxymorphone was administered intravenously (IV) to 10 dogs (0.4 mg/kg initial dose followed by 0.2 mg/kg three times at 20-minute intervals). Four hours after the last dose of oxymorphone, heart rates were less than 60 bpm in six dogs. After atropine (0.01 mg/kg IV) was administered, heart rate decreased in five dogs and sinus arrhythmia or second degree heart block occurred in four of them. A second injection of atropine (0.01 mg/kg IV) was administered 5 minutes after the first and the heart rates increased to more than 100 bpm in all six dogs. Ten minutes after the second dose of atropine, heart rate, cardiac output, left ventricular minute work, venous admixture, and oxygen transport were significantly increased, whereas stroke volume, central venous pressure, systemic vascular resistance, and oxygen extraction ratio were significantly decreased from pre-atropine values. The PaCO2 increased and the PaO2 decreased but not significantly. The oxymorphone-induced bradycardia did not produce any overtly detrimental effects in these healthy dogs. Atropine reversed the bradycardia and improved measured cardiovascular parameters.  相似文献   

4.
Fifteen adult dogs underwent elective ovariectomy. They were premedicated with 0.5 mg/kg methadone and 0.05 mg/kg(-1) atropine administered intramuscularly, and anaesthesia was induced with propofol and maintained with intravenous infusions of remifentanil at 0.6 microg/kg/minute and propofol; the mean (sd) rate of infusion of propofol throughout the period of anaesthesia was 0.33 (0.03) mg/kg/minute. The dogs were ventilated continuously with oxygen while they were anaesthetised. Their haemodynamic parameters were clinically acceptable during the period of anaesthesia. Two dogs received additional atropine to correct bradycardias of less than 60 bpm and several dogs received additional boluses of remifentanil or propofol to maintain an adequate depth of anaesthesia, as determined by a clinical assessment. The mean (range) time to the return of spontaneous respiration after stopping the remifentanil infusion was 11.1 (6.0 to 17.0) minutes, and the mean (range) time to the dogs standing was 38.0 (20.0 to 80.0) minutes. The quality of recovery was good in 12 of the dogs, two showed mild excitation in the immediate postoperative period and the other dog required additional analgesia with methadone.  相似文献   

5.
An open patch-graft technique for correction of pulmonic stenosis was performed in four dogs. A synthetic patch-graft was presutured to a partial-thickness incision in the right ventricular outflow tract and to the pulmonary artery along its cranial border. The pulmonary artery and right ventricle were incised during venous inflow occlusion, and dysplastic pulmonic valve leaflets were excised. The arteriotomy was closed by suturing the caudal margin of the incision to the patch-graft. The entire procedure was performed during mild hypothermia (30 degrees - 32 degrees C). The mean circulatory arrest time was 5.5 +/- 0.2 minutes. The mean systolic pressure gradient across the pulmonic valve before surgery was 121 +/- 29 mm Hg; after surgery it was 9 +/- 2 mm Hg.  相似文献   

6.
Evoked potentials were produced by anodal stimulation over the motor cortex in six dogs. Potentials were recovered from the cranial thoracic and caudal lumbar portions of the spinal cord, and the radial and sciatic nerves. Evoked potential averages were recorded every 1.5 minutes during 40 minutes of aortic occlusion and during 40 minutes of reperfusion. Mean amplitudes of evoked potentials recovered from the caudal lumbar spinal cord decreased to 50% of original values at minute 12.2. Upon release of occlusion, the evoked potentials returned to baseline levels and remained there throughout the period of reperfusion. Sciatic nerve amplitudes decreased to 50% of original values at minute 4.5. In no subject could wave forms be recovered after minute 9.0. Upon release of occlusion, the evoked potentials returned to baseline levels and above, then deteriorated to 29 +/- 12% after 40 minutes of reperfusion. We concluded that transcranially induced evoked potentials were highly sensitive to spinal cord ischemia. Evoked potentials recovered from the sciatic nerve were consistent with functional grey matter immediately upon reperfusion, but deteriorated during reperfusion.  相似文献   

7.
Cardiopulmonary effects of laparoscopic surgery were investigated in five crossbred dogs (21 ± 1.9 kg). Premedicated dogs were anesthetized with thiopental and maintained with halothane at 1.5 times minimum alveolar concentration in oxygen. Controlled ventilation maintained partial pressure of end-tidal co2 at 40 ± 2 mm Hg. Vecuronium was used for skeletal muscle relaxation. After instrumentation and stabilization, baseline measurements were made of cardiac output (thermodilution technique), mean systemic, mean pulmonary arterial and pulmonary wedge pressures, heart rate, saphenous vein and central venous pressures, and minute ventilation. Baseline arterial and mixed venous blood samples were drawn for analysis of pH, Pao2, Paco2, Pvo2, Pvco2, and bicarbonate concentrations. Systemic and pulmonary vascular resistances, oxygen delivery and consumption, shunt fraction, and dead space ventilation were calculated using standard formulas. Abdominal insufflation using co2 to a pressure of 15 mm Hg for 180 minutes resulted in significant ( P <.05) increases in heart rate (15 to 180 minutes), minute ventilation (75 to 135 minutes), and saphenous vein pressure (15 to 180 minutes), and decreases in pH (60 to 180 minutes) and Pao2 (60 to 180 minutes). For 30 minutes after desufflation, there was a significant decrease in Pao2, and increases in cardiac output, o2 delivery, and heart rate, compared with baseline. There was a significant increase in shunt fraction and decrease in pH at 15 minutes after desufflation only. The changes were within physiologically acceptable limits in these healthy, ventilated dogs.  相似文献   

8.
OBJECTIVE: To determine the effect of hypovolemia on the minimum alveolar concentration (MAC) of isoflurane in the dog. STUDY DESIGN: Randomized, cross-over trial. ANIMAL POPULATION: Six healthy intact mixed breed female dogs weighing 18.2-29.0 kg. METHODS: Dogs were randomly assigned to determine the MAC of isoflurane in a normovolemic or hypovolemic state with a minimum of 18 days between trials. On both occasions, anesthesia was initially induced and maintained for 40 minutes with isoflurane delivered in oxygen while vascular catheters were placed in the cephalic vein and dorsal metatarsal artery. In dogs assigned to the hypovolemic group, 30 mL kg(-1) of blood was removed at 1 mL kg(-1) minute(-1) from the arterial catheter. All dogs were allowed to recover from anesthesia. Thirty minutes after the discontinuation of isoflurane, anesthesia was re-induced with isoflurane in oxygen delivered by face mask. The tracheas were intubated, and connected to an anesthetic machine with a Bain anesthetic circuit. Mechanical ventilation was instituted at a rate of 10 breaths minute(-1) with the tidal volume set to deliver 10-15 mL kg(-1). Airway gases were monitored continuously and tidal volume was adjusted to maintain an end-tidal carbon dioxide level of 35-40 mmHg (4.67-5.33 kPa). Body temperature was maintained at 37-38 degrees C (98.6-100.4 degrees F). The MAC determination was performed using an electrical stimulus applied to the toe web and MAC was defined as the mean value of end-tidal isoflurane between the concentrations at which a purposeful movement did and did not occur in response to the electrical stimulus. The MAC values were compared between groups using a Student's t-test. RESULTS: The MAC of isoflurane was significantly less in hypovolemic dogs (0.97 +/- 0.03%) compared with normovolemic dogs (1.15 +/- 0.02%) (p < 0.0079). CONCLUSIONS AND CLINICAL RELEVANCE: The MAC of isoflurane is reduced in dogs with hypovolemia resulting from hemorrhage. Veterinarians should be prepared to deliver a lower percentage of isoflurane to maintain anesthesia in hypovolemic dogs during diagnostic and therapeutic procedures.  相似文献   

9.
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10.
Twenty eyes of 10 dogs with keratoconjunctivitis sicca (KCS) were treated by occlusion of the ventral nasolacrimal punctum with a silicone punctal plug in order to increase the volume of the remaining tear lake. Punctal size was measured using a commercially available punctal gauge and the appropriate sized plug was inserted under local anaesthesia. Seven dogs showed an increase in Schirmer tear test I (STT) value. STT values immediately prior to plug placement were 2.3 +/- 1.7 mm/minute. STT values with punctal occlusion were 6.1 +/- 4.1 mm/minute, giving a mean increase of 3.8 +/- 2.7 mm/minute (P<0.001). In 14 eyes of eight dogs, the increase in STT values was accompanied by a clinical improvement in the appearance of the ocular surface. In the three dogs with no increase in STT values, the use of punctal plugs reduced the frequency of artificial tear replacement therapy required to maintain a healthy ocular surface. These results show that use of punctal plugs in dogs with KCS may be appropriate where other lacrimomimetic medications have been unsuccessful.  相似文献   

11.
Central venous pressure (CVP), portal pressure (PP), and heart rate (HR) were monitored in 6 female, sexually intact, middle-age Beagles during temporary portal vein obstruction, anesthetic recovery, abdominal bandaging, and propranolol administration. Intraoperative baseline PP was 7.3 mm of Hg (+/- 1.7 SD). Portal pressure was significantly increased throughout portal vein occlusion, but returned to baseline values 2 minutes after release of the ligature. Central venous pressure was significantly decreased throughout portal vein occlusion, but did not differ significantly from baseline values 3 minutes after release of the portal vein ligature. Portal pressure increased significantly (8 +/- 3.3 mm of Hg) over baseline values after application of an abdominal bandage; however, CVP did not change significantly. During postoperative monitoring, CVP and PP did not change significantly from respective 18-hour mean postoperative values in resting dogs. At 60 and 75 minutes after surgery, heart rate was significantly increased over the 18-hour mean. Portal pressure and CVP, respectively, were significantly increased over intraoperative baseline values in the first hour and the first 8 hours after surgery. Postoperative CVP and HR were significantly correlated. Individual measurements of PP in dogs that were abdominal pressing during barking or defecation were significantly increased (9 +/- 3 mm of Hg) above measurements taken after cessation of abdominal press. Portal pressure measurements in standing dogs decreased 7.5 +/- 2 mm of Hg, compared with measurements of the same dog in lateral recumbency. Central venous pressure was inaccurate in dogs performing abdominal press. Portal pressure did not decrease significantly from baseline after injection of propranolol (2 mg/kg, IV).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

12.
Five mixed-breed dogs underwent splenic sequestration scintigraphy following intravenous injection of 647.5 to 740 MBq (17.5–20 mCi) of 99mTechnetium labeled autologous red blood cells (RBCs) that had been chemically denatured using two μg of stannous chloride. Left lateral dynamic images were obtained for 20 minutes after injection. Regions of interest (ROI) were drawn around the splenic body and ventral extremity, ventral liver and caudal abdominal great vessels and time activity curves created. Count density information was obtained and uptake ratios were calculated for the spleen ROI/vessel ROI, liver ROI/vessel ROI and spleen ROI/liver ROI at 1, 2.5, 5, 10, 15 and 20 minutes after injection. Two additional studies using different RBC denaturing procedures were done in four of the five dogs. In the second study, the stannous chloride level was doubled to 4.0 μg, while in the third study, the RBCs were denatured by addition of 2.0 μg of stannous chloride and heating at 49°C for 15 minutes. Progressive splenic uptake of denatured RBCs was seen in all dogs during the first 15 to 20 minutes of each study, no matter which denaturing technique was utilized. Significant increases in the spleen ROI:/vessel ROI and spleen ROI:liver ROI ratios were obtained at 5, 10, 15 and 20 minutes when compared to the 1 minute values for each of the labeling techniques. A significant difference was not identified between the three ratios at 15 minutes between the three labeling techniques. There was a trend of increasing values for each ratio where 2.0 μg of stannous chloride technique being the lowest, 4.0 μg of stannous chloride having an intermediate value and the heated technique had the highest values. The heating technique resulted in higher liver activity and increased variability of the mean liver ROI/vessel ROI ratios at all times (1, 2.5, 5,10, and 15 minutes). Using a non-linear least squares regression analysis, a double exponential equation fit the spleen ROI/vessel ROI and spleen ROI/liver ROI ratios for all three labeling techniques. Imaging of the spleen using all three techniques was acceptable, and a persistent blood pool image would allow for vascular imaging and cardiac gated studies 30 minutes after injection of the denatured, labeled autologous red blood cells. Veterinary Radiology & Ultrasound, Vol. 36, No. I, 1995, pp 57–63.  相似文献   

13.
ObjectiveTo determine the cardiovascular effects of a proprietary l-methadone/fenpipramide combination (Polamivet) alone and in addition to acepromazine in dogs.Study designProspective, randomized, experimental crossover study.AnimalsFive adult healthy Beagle dogs (one male and four females, weighing 12.8–16.4 kg).MethodsDogs were instrumented for haemodynamic measurements whilst anaesthetized with isoflurane. Three hours after recovery dogs received 0.025 mg kg?1 acepromazine (AP) or saline (SP) IM followed by 0.5 mg kg?1L-methadone/ 0.025 mg kg?1 fenpipramide IV after 30 minutes. Cardiac output using thermodilution, heart rate, mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary artery pressure (MPAP), pulmonary artery occlusion pressure (PAOP), haemoglobin concentration, arterial and mixed-venous blood gas analysis were measured and sedation evaluated at baseline (BL), 30 minutes after acepromazine or saline IM (A/S), 5 minutes after L-methadone/fenpipramide IV application (35), every 15 minutes for 1 hour (50, 65, 80, 95 minutes) and every hour until baseline cardiac output was regained. Standard cardiovascular parameters were calculated. Data were analyzed by repeated measures anova and paired t-tests with p < 0.05 considered significant.ResultsBaseline measurements did not differ. Cardiac index decreased after acepromazine administration in treatment AP (p = 0.027), but was not significantly influenced after l-methadone/fenpipramide injection in either treatment. In both treatments heart rate did not change significantly over time. Stroke volume index increased after A/S in both treatments (p = 0.049). Systemic vascular resistance index, MAP, CVP, MPAP, and pulmonary vascular resistance index did not change significantly after either treatment and did not differ between treatments. Dogs were deeply sedated in both treatments with a longer duration in treatment AP.Conclusions and clinical relevanceIn healthy dogs the dose of l-methadone/fenpipramide used in this study alone and in combination with acepromazine induced deep sedation without significant cardiovascular changes.  相似文献   

14.
OBJECTIVE: To evaluate the effects of the alpha2-adrenoceptor agonist medetomidine on respiratory rate (RR), tidal volume (V(T)), minute volume (V(M)), and central respiratory neuromuscular drive as determined by inspiratory occlusion pressure (IOP) during increasing fractional inspired concentrations of carbon dioxide (FiCO2) in conscious dogs. ANIMALS: 6 healthy dogs (3 males and 3 females). PROCEDURE: Dogs were administered 0, 5, or 10 microg of medetomidine/kg i.v. We measured RR, V(T), V(M), and IOP for the first 0.1 second of airway occlusion (IOP0.1) during FiCO2 values of 0%, 2.5%, 5.0%, and 75% at 15 minutes before and 5, 30, and 60 minutes after administration of medetomidine. RESULTS: Increases in FiCO2 significantly increased RR, V(T), and V(M). The i.v. administration of 5 and 10 microg of medetomidine/kg significantly decreased RR and V(M) at 5, 30, and 60 minutes for FiCO2 values of 2.5% and 5.0% and at 30 and 60 minutes for an FiCO2 value of 75%. The IOP0.1 was decreased after 30 minutes only for an FiCO2 value of 7.5% in dogs administered 5 and 10 microg of medetomidine/kg. The IOP0.1 was decreased at 60 minutes after administration of 10 microg of medetomidine/kg for an FiCO2 value of 7.5%. CONCLUSIONS AND CLINICAL RELEVANCE: The i.v. administration of medetomidine decreases RR, V(M), and central respiratory drive in conscious dogs. Medetomidine should be used cautiously and with careful monitoring in dogs with CNS depression or respiratory compromise.  相似文献   

15.
Four standardbred horses with subcutaneously relocated carotid arteries were given a seven week training programme of treadmill exercise at a gradient of 19 per cent in order to assess if there were any effects of exercise and training on haematology, arterial blood gas and acid base measurements, plasma biochemistry and heart rate. The exercise consisted of one minute walking at 110 metres/minute followed by five minutes trotting at 200 metres/minute, twice daily in the first week. The period of trotting exercise was increased by one minute per week so that by the seventh week the horses were being given 12 minutes trotting twice daily. Before training commenced venous blood samples, for complete blood counts and plasma biochemistry, and arterial samples, for blood gas, acid base and lactate measurements, were taken at rest, after five minutes and 15 minutes of treadmill exercise (200 metres/minute) and 30 minutes and 60 minutes after completing the exercise. Heart rate was measured by telemetric electrocardiogram at similar intervals. This exercise test and blood collection were repeated after one, three, five and seven weeks of training. The only significant changes were a decrease in exercise lactate with training, increases in exercise and recovery total protein. The haematological response to treadmill exercise included an increase in certain red cell parametes and a leucocytosis which was caused by both a neutrophilia and a lymphocytosis. These effects had largely disappeared by 30 minutes after exercise and all values had returned to resting values by one hour after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
Gastric dilatation-volvulus (GDV) was created experimentally and maintained for 90 minutes in 16 anesthetized, mixed-breed dogs. After the GDV was corrected, normal saline solution (0.044 mL/kg intravenously [IV]) was administered to eight dogs (controls), and flunixin meglumine (2.2 mg/kg IV) was administered to eight dogs. Microspheres labeled with radioactive cobalt, scandium, tin, or niobium were injected intravenously at baseline (before GDV) and minutes 90, 100, and 270, respectively, to determine tissue blood flows. Plasma endotoxin and prostacyclin were measured at the same intervals. Electrocardiogram, mean arterial pressure, portal pressure, and cardiac output were recorded continuously. Dogs were euthanatized at minute 270 and necropsied. There was no significant difference between treatment groups for any measured variable at any time. Endotoxin levels increased significantly during GDV. Prostacyclin levels were lower in dogs treated with flunixin meglumine than in controls at minutes 210 and 270. Histopathologic findings were similar for all dogs and consistent with those associated with endotoxemia. Flunixin meglumine treatment did not alter cardiac indices or tissue blood flows significantly. However, elevation of prostacyclin was inhibited by flunixin meglumine, which suggested that continued effects of endotoxic damage might be attenuated or inhibited.  相似文献   

17.
Thoracic duct embolization was created by injecting an isobutyl 2-cyanoacrylate/iophendylate (IBCA) mixture through a cannulated mesenteric lymphatic vessel in eight normal dogs. Aqueous contrast lymphangiography was repeated at minute 10 and week 6. Six dogs were euthanatized at week 6 and two dogs at month 6. Embolization with 1.5 to 3.9 ml of the mixture resulted in complete obstruction of the thoracic duct in all eight dogs. Results of lymphangiography in six dogs at week 6 showed a persistent, complete obstruction of the thoracic duct in six dogs and alternate lymphaticovenous anastomoses in four dogs. Histologically, there were a sclerosing granulomatous response surrounding the lymphatic embolus, mild congestive changes in the mesenteric lymph nodes, and mild lacteal dilatation in the jejunum. The procedure was well tolerated with only a few complications. One dog suffered partial thrombosis of the cranial vena cava by the injected material with later dislodgement and embolization of a pulmonary artery branch. Modifications have been made in the injection procedure to avoid this complication. This technique for occlusion of the thoracic duct shows potential for clinical use in the management of canine chylothorax. The obstruction appears to be complete and permanent, and surgical/anesthetic time is decreased greatly from previously described procedures.  相似文献   

18.
A novel surgical approach, using portal venotomy during total hepatic vascular occlusion, was used to locate and attenuate congenital intrahepatic portosystemic shunts in nine dogs. Shunt location was consistent with a persistent ductus venosus in only two dogs. In the remaining seven dogs the shunts were window-like orifices arising from either the left (two dogs) or right portal vein branch (five dogs) and communicating with the ipsilateral hepatic vein or caudal vena cava. The transportal approach using total hepatic vascular occlusion consistently provided good access to the portosystemic shunts, including those with window-like communications. A 7 to 16 minute period of total vascular occlusion was well-tolerated hemodynamically, with few intraoperative complications. Intrahepatic shunts were successfully attenuated in eight dogs, while one dog with portal atresia was euthanatized. The postoperative course was complicated by high protein pulmonary edema (one dog), an encapsulated biliary pseudocyst (one dog) and uncontrollable hemorrhage caused by an uncharacterized coagulopathy (one dog). Three dogs required a second operation to further attenuate their shunts. The clinical condition of all seven surviving dogs was improved after surgery.  相似文献   

19.
Cor Triatriatum Dexter is a rare, congenital cardiac defect in which the right atrium is partitioned into two compartments, effectively creating a triatrial heart. The clinical signs exhibited by the patient usually relate to impeded venous return via the caudal vena cava. The two dogs in this report both displayed ascites from a young age and grew poorly. In both cases the diagnosis was made during echocardiographic examination and was confirmed by angiography. Both dogs were successfully treated by resection of the partitioning membrane within the right atrium, using hypothermia and inflow occlusion to achieve a clear surgical field. Both dogs recovered well, their clinical signs resolved and they have grown to normal adult size.  相似文献   

20.
Cardiopulmonary effects of etomidate administration were studied in hypovolemic dogs. Baseline cardiopulmonary data were recorded from conscious dogs after instrumentation. Hypovolemia was induced by withdrawal of blood from dogs until mean arterial pressure of 60 mm of Hg was achieved. Blood pressure was maintained at 60 mm of Hg for 1 hour, by further removal or replacement of blood. One milligram of etomidate/kg of body weight was then administered IV to 7 dogs, and the cardiopulmonary effects were measured 3, 15, 30, and 60 minutes later. After blood withdrawal and prior to etomidate administration, heart rate, arterial oxygen tension, and oxygen utilization ratio increased. Compared with baseline values, the following variables were decreased: mean arterial pressure, mean pulmonary arterial pressure, central venous pressure, pulmonary wedge pressure, cardiac index, oxygen delivery, mixed venous oxygen tension, mixed venous oxygen content, and arterial carbon dioxide tension. Three minutes after etomidate administration, central venous pressure, mixed venous and arterial carbon dioxide tension, and venous admixture increased, and heart rate, arterial and venous pH, and arterial oxygen tension decreased, compared with values measured immediately prior to etomidate administration. Fifteen minutes after etomidate injection, arterial pH and heart rate remained decreased. At 30 minutes, only heart rate was decreased, and at 60 minutes, mean arterial pressure was increased, compared with values measured before etomidate administration. Results of this study indicate that etomidate induces minimal changes in cardiopulmonary function when administered to hypovolemic dogs.  相似文献   

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