Dražen Vnuk

Feline high-rise syndrome: 119 cases (1998-2001)

High-rise syndrome was diagnosed in 119 cats over a 4-year period. 59.6% of cats were younger than one year, and the average height of the fall was four stories. High-rise syndrome was more frequent during the warmer period of the year. 96.5% of the presented cats, survived after the fall. 46.2% of cats had fractured limbs; 38.5% of fractures were of the forelimb, 61.5% of the hindlimb. The tibia was fractured most often (36.4%), followed by the femur (23.6%). 78.6% of femoral fractures were distal. The mean age of patients with femoral fractures was 9.1 months, and with tibial fractures 29.2 months. Thoracic trauma was diagnosed in 33.6% of cats. Pneumothorax was diagnosed in 20% of cats, and pulmonary contusions in 13.4%. Falls from the seventh or higher stories, are associated with more severe injuries and with a higher incidence of thoracic trauma.

Determination of the toxic dose of lidocaine in dogs and its corresponding serum concentration

LIDOCAINE is a local analgesic drug that is often used in dogs and cats, and also in other domestic, wild, exotic and laboratory animals. It is used in a variety of ways: topically, by local infiltration, by epidural injection, by nerve block, or by intravenous injection into a peripheral vein to provide limb analgesia. In human beings, lidocaine has been used intravenously in low doses to reduce the pain associated with the injection of some intravenous agents (Nolan 2000). Lidocaine also has an anti-arrhythmic effect, and is used for the acute control of life-threatening ventricular arrhythmia in dogs and cats (Lunney and Ettinger 1995). In equine medicine, it is also used in the treatment of postoperative ileus (Malone and others 1998). Lidocaine has significant side effects: the most common sign of intoxication is seizure, while bradyarrhythmia and conduction disturbances are more rare (Lunney and Ettinger 1995). Muscle tremor is a common clinical sign of lidocaine intoxication in horses (Meyer and others 2001). The approximate maximum dose by infiltration before toxic signs become apparent is not known with any certainty, although Hall and others (2000a) have quoted it to be 6 to 10 mg/kg in dogs. According to Skarda (1998), the convulsive toxic dose of intravenously administered lidocaine in conscious dogs is 11 to 20 mg/kg and the lethal dose is 16 to 28 mg/kg. Lidocaine in biological samples has been analysed by immunoassay (Elin and others 1997, Liu-Allison and others 1997), reversed-phase liquid chromatography (Manna and others 2002), and gas chromatography-mass spectrometry (GC-MS) (Ohshima and Takayasu 1999). This short communication describes a study to describe lidocaine intoxication in dogs, to determine the total toxic dose of lidocaine and serum lidocaine concentrations that resulted in clinical signs of intoxication, and to record the effects of lidocaine on the cardiovascular system. It was hypothesised that lidocaine intoxication is common because the therapeutic and toxic doses are similar. The study was approved by a legal committee; 19 dogs were studied, three males and 16 females aged between three and 60 months (mean [sd] 19·3 [16·3] months), and weighing between 2·2 and 24·8 kg (14·5 [7·9] kg). During the experiment, the animals were placed in sternal recumbency on the table, and a standard microclimate was maintained in the room. Emotional reassurance (gentle restraint, petting and talking) was provided by the handler throughout the whole procedure. Food was withheld for six hours before the study. The health of the dogs was determined by means of a clinical examination. The dogs’ blood pressure was measured by an oscillometric method using a cuff width of 40 per cent of the circumference of the metacarpus, and the heart rate was measured at the femoral artery. An oscillometric manometer was used (Neonatal model BC 203 NC automated sphygmomanometer; Air-shields). An electrocardiogram (ECG) was also recorded (Ultraview 1050 anesthesia monitor; Spacelabs Medical). An intravenous catheter (20, 22 or 24 G) was inserted into the cephalic vein, and a 3·5 ml blood sample was taken from the catheter (BD vacutainer SST II Advance 3·5 ml). For drug administration, a syringe pump (SEP 11S; Ascor) was used. The syringe was connected to the intravenous catheter by means of an extension line. An initial dose of 4 mg/kg lidocaine (Lidokain 2 per cent; Belupo) was administered intravenously, followed by a constant-rate infusion at a dose of 0·3 mg/kg per minute. After the lidocaine was administered, the following parameters were measured at 10-minute intervals until a toxic effect was observed: the systolic, diastolic and mean blood pressures, heart rate and ECG. Blood samples were taken at 10minute intervals from another limb, from the cephalic vein or the lateral saphenous vein, using a needle. A toxic effect was determined when a muscle tremor was seen, and the infusion of lidocaine was immediately discontinued. The total dose administered (that is the toxic dose) was recorded, and the systolic, diastolic and mean blood pressures, heart rate and the ECG were recorded again. A final blood sample was then taken. A saline infusion was administered, and the dog was monitored for the next hour. After centrifugation, a minimum of 1 ml serum was removed and frozen at –70°C. Lidocaine in the serum was analysed by GC-MS. Statistica 5.0 for Windows was used for the statistical analysis (Statsoft). Shapiro Wilks’ W test was used to determine the distribution of the lidocaine concentration measurements and the distribution of heart rate and blood pressures. Analysis of variance and Duncan’s test were used to compare between age groups. Significance was set at P<0·05 for all tests. The mean (sd) serum lidocaine concentration 10 minutes after the initial administration of lidocaine as 2·4 (0·6) μg/ml, and after 20 minutes it was 2·7 (1·0) μg/ml. The mean serum lidocaine concentration at the time of observation of toxic effect (LTC) was 2·7 (1·1) μg/ml. The mean time from the beginning of lidocaine administration to the observation of a toxic effect was 24 (13·6) minutes, and the total toxic dose of lidocaine was 11·1 (4·1) mg/kg. Six of the dogs (31·58 per cent) were three to five months old, six (31·58 per cent) were seven to 23 months old, and seven (36·84 per cent) were 24 to 60 months old. To determine whether there was any age-dependent variation in the parameters, the data were broken down by age; the mean (sd) values for dogs in the three age groups are shown in Table 1. Before the administration of lidocaine, the mean (sd) was 136·7 (15·1) bpm; on observation of the toxic effect it was 129·4 (24·8) bpm. The mean systolic blood pressure before the administration of lidocaine was 113·3 (12·3) mmHg, and at the observation of toxic effect it was 82·6 (8·5) mmHg, this decrease was significant. The corresponding mean diastolic blood pressures were 75·8 (13·8) mmHg and 85·9 (13·7) mmHg, respectively, and the overall mean blood pressures were 94·6 (8·4) mmHg before the administration of lidocaine and 91·9 (14·4) mmHg, upon observation of toxic effect. During the study, no changes in ECG parameters (P-wave duration, P=R interval, R-R interval and Q-T interval) were observed that were considered to be outside the normal range. The LTC in the present study (2·7 [1·1] μg/ml) was significantly lower than in the only other published LTC in dogs, 8·21 (1·69) μg/ml (Wilcke and others 1983). This difference could be explained by different modes of lidocaine administration (rapid v slow rate of administration) or the use of a different sign to indicate the time when toxic effects began (muscle tremor in the present study; the toxic extension phase in the study of Wilcke and others [1983]). In cats, the mean highest serum concentration of lidocaine after intravenous regional anaesthesia was 3·10 (1·11) μg/ml; signs of intoxication were not observed (Kushner and others 2002). In human volunteers, muscle fasciculations Veterinary Record (2007) 160, 374-375

Aminotransferases after experimental pneumoperitoneum in dogs.

Background:  Laparoscopic surgery has rapidly become a popular and widely used technique. Elevated intra abdominal pressure due to gas insufflation for laparoscopic surgery may result in a number of local and systemic effects on the organism. The effects of pneumoperitoneum on the cardiovascular and respiratory system are well known today, but very few studies have been carried out on the consequences of pneumoperitoneum on hepatic integrity. The aim of the present study was to assess changes in aminotransferases, bilirubin and prothrombin time after pneumoperitoneum in dogs.

Application of a semitendinosus muscle flap in the treatment of perineal hernia in a cat

The article described one case of perineal hernia in a cat treated by method of application of a semitendinosus muscle flap.

Comparison of the Effects of Low Intra-Abdominal Pressure and Pentoxifylline on Oxidative Stress during CO2 Pneumoperitoneum in Rabbits

Background: The aim of this study was to investigate the effect of low-pressure pneumoperitoneum and pentoxifylline, a methylxanthine derivative, in the prevention of injury caused by free oxygen radicals generated during CO2 pneumoperitoneum. Methods: Twenty-eight rabbits were allocated randomly to 4 groups. Control group rabbits (group 1) were subjected to anesthesia for 60 min; group 2 and 3 animals were subjected to a CO2 pneumoperitoneum (15 or 7 mm Hg); and group 4 rabbits received 50 mg/kg pentoxifylline, followed by a 15-mm-Hg pneumoperitoneum. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), lipid hydroperoxide, glutathione reductase and total antioxidant status were measured. Results: Compared with group 1, a significant increase in lipid hydroperoxide levels at the end of the pneumoperitoneum and 30 min after deflation and a significant decrease in total antioxidant status 24 h after deflation were recorded in group 2. In addition, a significant increase was observed in ALT, AST and LDH levels. These changes were attenuated by low-pressure pneumoperitoneum, whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. Conclusion: Low-pressure pneumoperitoneum could attenuate ischemia/reperfusion injury induced by CO2 pneumoperitoneum in a rabbit model whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. Pentoxifylline did not prevent the development of oxidative stress.

Lidocaine serum concentration after epidural administration in combination with morphine and fentanyl in rabbit--a preliminary study.

Morphine and fentanyl are often used as adjuvants in epidural anesthesia to prolong analgesia. The aim of this study was to evaluate the impact of addition of morphine or fentanyl to lidocaine on serum lidocaine concentrations in rabbits after epidural administration. During general anesthesia, rabbits of the group L received epidurally 2% lidocaine, rabbits of the group LM 2% lidocaine and morphine, and rabbits of the group LF 2% lidocaine and fentanyl. Blood for determination of serum lidocaine concentration was taken before anesthesia and in first 90 min after epidural administration. After 5, 10, and 25 min in the group L the lidocaine serum concentrations were the lowest, while in the group LM the lidocaine serum concentrations were the highest. Morphine and fentanyl did not cause significant changes of serum lidocaine concentration in rabbits and may be used as adjuvant in epidural anesthesia without significant increase in lidocaine absorption from epidural space.

Effect of Splenectomy and Autologous Spleen Transplantation on the Serum Platelet-Activating Factor Acetylhydrolase (PAF-AH) Activity and Acute Phase Response (APR) in a Porcine Model

The aim of this study was to evaluate the inflammatory response after total splenectomy and spleen autotransplantation in a porcine model by measuring serum platelet-activating factor acetylhydrolase activity, C-reactive protein and albumin concentrations. Nineteen piglets were used in the experiment. After induction of anesthesia, animals were randomly divided into three groups: sham-operation with spleens intact (n = 6), total splenectomy (n = 6), and splenic autotransplantation (n = 7) with small fragments of the spleen autotransplanted into the greater omentum. The blood samples were taken just before surgery and on day 1st, 5th, 12th, 26th and 40th postoperatively. PAF-AH activity, CRP and albumin concentrations were assayed in the sera. After total splenectomy, PAF-AH activity was significantly increased on day 5th, while there was no significant increase after spleen autotransplantation or the sham-operation. CRP was significantly increased after surgery in all experimental groups. Albumin was significantly decreased after surgery from day 5th until day 40th in splenectomized and autotransplanted pigs. Increased PAF-AH activity after splenectomy and spleen autotransplantation might be attributed to inflammatory conditions due to the loss of splenic tissue and trauma. Time-course increase of CRP, in all groups after surgery suggests post-injury inflammatory response due to tissue lesion during operation.

The effect of repeated sevoflurane and nitrous oxide exposure on immunity in rabbits

1University Department of Anesthesiology, Resuscitation and Intensive Care, Sveti Duh University Hospital, Zagreb, Croatia 2School of Medicine, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia 3Department of Biology, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia 4Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia 5Clinic for Surgery, Orthopedics and Ophthalmology, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia

Osteosynthesis of the radius and ulna in a brown hare lepus europeus

Six months old brown hare was presented at the Surgery Clinic for evaluation of a right forelimb third grade lameness. Full physical examination, blood samples for complete blood count, and serum biochemistry were performed. Radiographic examination from anteroposterior and lateral views confirmed a old, closed, complete, non-comminuted, transverse fracture in the middle part of right radius and ulna. Fracture repair in the brown hare is a similar to those in cats and dogs. Stabilization of fractures with bone plates and screws are the most popular methods of fracture fixation. Osteosynthesis was performed by 2.0, 8-hole stainless steel Synthes dynamic compression plate, DCP (Synthes Holding AG, 4500 Solothurn, Switzerland) placed on radius in neutral position to achieve anatomical repositioning of fragments and to restore normal biological function of the limb. Surgical procedure was performed within 45 minutes in order to reduce residence in a hospital environment, which hares generally find stressful. The fracture was assessed as clinically stable in the 5th day postoperatively and the animal was weightbearing on its forelimb. Osteosynthesis of hare radius using DCP plate 2.0 is a good method of fixation and healing fractures. After performing full clinical examination and bloodwork, controled and modulated anaesthesia and analgesia, it is possible to perform osteosynthesis with excellent outcome and also a good way to preserve fragile wildlife.

The effect of preanesthetic administration of lactated ringer solution on blood pressure in isoflurane-anesthetized horses.

Hypotension induced by volatile agents is particularly notorious in horses and it is probably one of the major causes of the high anaesthetic risk in this species. In the present study we investigated the influence of 10 mL/kg lactated Ringer solution on the values of arterial blood pressure during the elective surgical procedure, administered right before the induction of anaesthesia. The goal was to establish if it was possible to lower the risk of hypotension development with this type of therapy. Nine horses divided in two groups were used in this study. All the horses were submitted to the same anesthetic regimen. The second group of horses received 10 mL/kg i.v. lactated Ringer solution in the 15 minutes time before the induction of anesthesia. The effect of lactated Ringer solution was noted at the beginning of anesthesia. Statistically significant differences among groups were noticed during the first measurement. The results indicate that the suggested method may provide a very simple way of supporting the cardiovascular system at least at the beginning of the surgical procedure.