Changes in endotracheal tube intracuff pressure and air leak pressure over time in anesthetized Beagle dogs.

OBJECTIVE: To evaluate endotracheal tube intracuff pressure (Pcuff) changes over time and the effect of these changes on air leak pressure (Pleak). STUDY DESIGN: Prospective experimental study. ANIMALS: A group of nine healthy adult Beagle dogs. METHODS: In part I, in vitro measurements of Pcuff were recorded for 1 hour in eight endotracheal tubes subjected to four treatments: room temperature without lubricant (RT0L), room temperature with lubricant (RTWL), body temperature without lubricant (BT0L), and body temperature with lubricant (BTWL). In part II, nine dogs were endotracheally intubated and Pleak was evaluated at Pcuff of 25 mmHg. Subsequently, Pcuff was reset to 25 mmHg (baseline) and Pcuff measurements were recorded every 5 minutes for 1 hour. Subsequently, a second Pleak measurement was recorded at the current Pcuff. The data were analyzed using Wilcoxon signed-rank test, repeated measures anova and Mann-Whitney U test. RESULTS: In part I, Pcuff differed significantly between the RT0L and RTWL treatments at 5-60 minutes, and between the BT0L and BTWL treatments at 5-35, 55 and 60 minutes (p < 0.05). In part II, compared with baseline pressures, mean Pcuff decreased to <18 mmHg at 10 minutes and significant decreases were recorded at 15-60 minutes (Pcuff range: 10.0 ± 4.9 to 13.4 ± 6.3 mmHg, mean ± standard deviation). Significant differences were observed between the first and second Pleak measurements (p = 0.034). Pleak decreased in six of nine dogs, was not changed in two dogs and increased in one dog. CONCLUSIONS AND CLINICAL RELEVANCE: Significant decreases in Pcuff over time were measured. Pleak may decrease during anesthesia and increase the risk for silent pulmonary aspiration. The results indicate the need for testing Pcuff more than once, especially at 10 minutes after the onset of anesthesia.

The investigation of airway management capacity of v-gel and cobra-PLA in anaesthetised rabbits.

PURPOSE: To evaluate the applicability and airway management capacity of v-gel® and Cobra PLA in rabbit anaesthesia during assisted (AV) or controlled ventilation (CV). METHODS: This study was carried out in 44 adult New Zealand white rabbit. Baseline arterial pH, PaCO2 and PaO2 values were recorded. Anaesthesia was induced with 5 mg/kg xylasine and 35 mg/kg ketamine HCI combination. AV rabbits were assigned as; control (CG-AV; n=5), LMA (LMA-AV; n=5), cobra PLA (PLA-AV; n=5) and v-gel (v-gelAV; n=5). Rabbits have CV were also assigned as; ET (ET-CV; n=6), LMA (LMA-CV; n=6), cobraPLA (PLA-CV; n=6) and v-gel (v-gelCV; n=6). All measurements were repeated 1st, 5th, 15th and 30th mins during anaesthesia. RESULTS: The less insertion time, number of attempt and complications are recorded in v-gel applied rabbits compared to other apparatus. For arterial pH values significant differences are recorded in especially at 15th and 30th min between groups of CV (p<0.005 or p<0.001). All groups had similar results with each other during anaesthesia for PaCO2 except for LMA-CV group. CONCLUSION: The v-gel may be used as airway device in rabbit anaesthesia undergoing AV or CV and also can be a suitable alternative to endotracheal tubes and laryngeal mask airway.

The investigation of airway management capacity of v-gel and cobra-PLA in anaesthetised rabbits

PURPOSE: To evaluate the applicability and airway management capacity of v-gel(r) and Cobra PLA in rabbit anaesthesia during assisted (AV) or controlled ventilation (CV). METHODS: This study was carried out in 44 adult New Zealand white rabbit. Baseline arterial pH, PaCO2 and PaO2 values were recorded. Anaesthesia was induced with 5 mg/kg xylasine and 35 mg/kg ketamine HCI combination. AV rabbits were assigned as; control (CG-AV; n=5), LMA (LMA-AV; n=5), cobra PLA (PLA-AV; n=5) and v-gel (v-gelAV; n=5). Rabbits have CV were also assigned as; ET (ET-CV; n=6), LMA (LMA-CV; n=6), cobraPLA (PLA-CV; n=6) and v-gel (v-gelCV; n=6). All measurements were repeated 1st, 5th, 15th and 30th mins during anaesthesia. RESULTS: The less insertion time, number of attempt and complications are recorded in v-gel applied rabbits compared to other apparatus. For arterial pH values significant differences are recorded in especially at 15th and 30th min between groups of CV (p<0.005 or p<0.001). All groups had similar results with each other during anaesthesia for PaCO2 except for LMA-CV group. CONCLUSION: The v-gel may be used as airway device in rabbit anaesthesia undergoing AV or CV and also can be a suitable alternative to endotracheal tubes and laryngeal mask airway. .

Alfaxalone induction dose following administration of medetomidine and butorphanol in the dog.

OBJECTIVE: To determine in dogs the effects of medetomidine and butorphanol, alone and in combination, on the induction dose of alfaxalone and to describe the induction and intubation conditions. STUDY DESIGN: Prospective, randomized, blinded clinical trial. ANIMALS: Eighty-five client-owned dogs (ASA 1 or 2). METHODS: Subjects were block randomized to treatment group according to temperament. The treatment groups were: medetomidine 4 microg kg(-1) (M), butorphanol 0.1 mg kg(-1) (B), or a combination of both (MB), all administered intramuscularly. After 30 minutes, a sedation score was assigned, and alfaxalone 0.5 mg kg(-1) was administered intravenously over 60 seconds by an observer who was unaware of treatment group. Tracheal intubation conditions were assessed and, if tracheal intubation was not possible after 20 seconds, further boluses of 0.2 mg kg(-1) were given every 20 seconds until intubation was achieved. Induction dose and adverse events (sneezing, twitching, paddling, excitement, apnoea and cyanosis) were recorded; induction quality and intubation conditions were scored and recorded. RESULTS: The mean dose of alfaxalone required for induction was similar for groups M and B: 1.2 +/- 0.4 mg kg(-1). The mean dose requirement for group MB (0.8 +/- 0.3 mg kg(-1)) was lower than groups M and B (p < 0.0001). Induction dose was not influenced by temperament or level of sedation. Induction and intubation scores did not differ between treatment groups. Adverse events were noted in 16 dogs; there was no association with treatment group, temperament or level of sedation. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine and butorphanol administered in combination reduce the anaesthetic induction dose of alfaxalone compared to either agent alone. This difference should be taken into account when using this combination of drugs in a clinical setting.

Successful management of rabbit anesthesia through the use of nasotracheal intubation.

Although nasotracheal intubation in the rabbit has been briefly described, scientific assessment of the procedure has not been reported. In this report we describe nasotracheal intubation performed in 38 male New Zealand White rabbits (3.0 to 5.5 kg) used for a vascular patch study. The rabbits were placed under general anesthesia twice, with 2 mo between the initial and final intubations. Rabbits were intubated by the oral or nasotracheal route and compared. Previous literature dismissed nasotracheal intubation, citing the possibility of introducing pathogens into the lungs and the necessity of high oxygen flow rates (presumably greater than 3 L/min). However, no clinical signs of respiratory disease were noted among the study animals, nor were high oxygen flow rates necessary. Several key points collectively facilitated a successful procedure. Total relaxation was essential, modification of the classic blind approach eased placement, a correct approach was necessary, and our development of a unique method of securing the tube improved tube management. The findings suggest that nasotracheal intubation can be used as an easy, less traumatic method of rabbit intubation when compared with orotracheal intubation.

Ventral recumbency is crucial for fast and safe orotracheal intubation in laboratory swine.

The aim of this study was to find the fastest, easiest and safest method of achieving orotracheal intubation for general anaesthesia in laboratory pigs. Twenty-one Yorkshire x Landrace crossbreed male castrated pigs (32.9 +/- 4.8 kg) were investigated. Dorsal and ventral recumbency are the alternatives most frequently described for animal positioning during intubation procedures. Based on standardized induction of general anaesthesia using pentobarbital and remifentanil, the dorsoventral and ventrodorsal positions were compared with regard to the time needed, changes in oxygenation and circulatory response. Positioning was found to be crucial for fast orotracheal intubation. The time required for safe intubation is significantly shorter with the ventrodorsal position (17.3 s) in comparison with the dorsoventral position (58.4 s; P < 0.001). Hypoxia did not occur in either group. A significant drop in systolic blood pressure was observed in both groups. Diastolic and mean arterial pressures were not influenced by intubation. A significant increase in heart rate was observed in pigs intubated in ventral recumbency, but not after intubation in the dorsal position. Preoxygenation before intubation is vitally important for preventing hypoxia. With regard to clinical practice, the haemodynamic changes observed in this investigation do not appear to be relevant, as the mean arterial pressure was not altered and heart rates only increased moderately. It may be concluded that the ventrodorsal position can be recommended for orotracheal intubation in pigs as the first choice for providing a smooth and fast airway.

Postanaesthetic tracheal strictures in three rabbits.

Within an 11-day period, three rabbits were anaesthetized for neutering. All were endotracheally intubated with 12 cm long, 2.5 mm (inner diameter [ID]) polyvinylchloride (PVC) tubes. All rabbits developed clinical signs of dyspnoea and upper respiratory tract obstruction, 17-21 days later. One rabbit was found dead; the other two were treated, but one was euthanized and one died. At necropsy examination, focal chronic inflammation and significant localized narrowing of the tracheal lumen was found in all cases. The affected sites corresponded to the position of the bevel of the endotracheal tube (ETT) during anaesthesia. Histopathology could not differentiate between a traumatic or chemical cause for the narrowing. Possible causes include trauma by the bevel of the ETT when turning the rabbit or preparing the surgical site or a chemical burn from incorrect disinfection or inadequate rinsing of the tubes. Iatrogenic tracheitis should be considered as a cause of dyspnoea, when clinical signs arise 2-3 weeks after anaesthesia.

Endotracheal isoflurane anesthesia for chick auditory surgery.

Survival surgeries upon chicks are commonly used in auditory research. Appropriate anesthesia is usually obtained with intramuscular or intraperitoneal injections of systemic agents. These techniques have several drawbacks, including delayed onset of anesthesia, difficulty in adjusting the dosage to accomodate individual animals' different responses, prolonged recovery times, and in some cases substantial mortality. We present a technique of administering inhaled isoflurane via an endotracheal tube which we have used for over a year with excellent results. With this agent, onset of deep anesthesia is very rapid, dosage can be titrated readily, overdosage is survivable, complete recovery occurs within a few minutes and mortality is rare. This technique may be valuable for other auditory scientists performing survival surgery in avian species.

Thiamylal-sparing effect of midazolam for canine endotracheal intubation. A clinical study of 118 dogs.

One hundred eighteen dogs were studied at three veterinary teaching hospitals after the administration of midazolam (0.1 mg/kg, intravenously [IV]) or a placebo. Midazolam and placebo treatments were randomized and blinded to the investigators. The dose of thiamylal required for tracheal intubation 3 to 5 minutes after midazolam or placebo was calculated. The dose of thiamylal at the three hospitals was 10.6, 9.8, and 10.1 mg/kg i.v. after midazolam, and 12.1, 11.2, and 11.6 mg/kg i.v. after placebo. Pooled data from the three hospitals yielded a significant (p < .001) decrease in mean IV thiamylal dose after midazolam (10.2 mg/kg) compared with placebo (11.6 mg/kg). Overall, there was a 12% decrease in the dose of thiamylal required for tracheal intubation after midazolam compared to that after the placebo. The thiamylal dose was significantly (p < .001) decreased after midazolam compared with placebo for dogs weighing more than 15 kg but not for dogs weighing less than 15 kg.

A technique to anesthetize turtles with ether.

A technique to anesthetize turtles with ether is presented, in which a plastic cannula is passed through the glottis into the trachea. This procedure avoids apnea and allows ether vapours obtained from a chamber to be introduced, by the animal respiratory movements or by means of a pump, into the animal lungs. The anesthesia is rapidly obtained and lasts from 45-90 minutes. The time of recovery from anesthesia ranged from 60-90 minutes. With this technique no deaths were observed and the same animal could be anesthetized repeatedly.

[Dysfunction of the oviducts and salpingectomy in a boa (C. constrictor). Description of a case]. / Dysfunctie van de eileider en salpingectomie bij een boa (C. constrictor). Beschrijving van een geval.

When a boa was producing lumps of proteinaceous material during labour, and administration of calcium and oxytocin failed to be effective, and lumps continued to be palpable, it was decided to perform (partial) salpingectomy. Premedication consisted in administration of metomidate, anaesthesia being produced by halothane, oxygen and nitrous oxide given by intubation with a cuffed tube. The incision was made in the median line; the fat corpuscles were separated along the abdominal veins to gain access to the coelomic cavity; those portions of the two oviducts which showed changes were resected. The abdominal wall was sutured using intradermal sutures. Dressing of the wound.

A method for producing forced expirograms in laboratory animals.

A method is described for the production of forced expirograms in anaesthetized laboratory animals, using a whole-body plethysmograph and a Hewlett-Packard (HP) 1000-F computer.

Succinylcholine infusion associated with hyperthermia in ponies anesthetized with halothane.

Succinylcholine was administered by infusion to halothane-anesthetized ponies to determine dosage requirements for surgical relaxation up to 3 hours' duration. This was not possible to do, since 4 of 6 ponies studied developed severe reactions characterized by prolonged muscle fasciculations after the initial succinylcholine dose, muscle rigidity, hyperthermia, hypercapnia, tachycardia, increasing pulse pressure, and metabolic acidosis. The reactions resembled those associated with malignant hyperthermia, a disease recognized in persons and swine. Two ponies showed signs of the phase II or desensitization block of succinylcholine. All ponies recovered from anesthesia without signs of muscle injury.

Anesthetic and analgesic considerations in the experimental animal.

Many new compounds and combinations of many of the more traditional drugs have been used in a wide range of species. This, plus the rapid development in equipment for inhalational anesthesia, has simplified the restraint, anesthetic, post-surgical, and analgesic management of experimental animals.

Flexible fiberoptic bronchoscopy of chimpanzees.

Five 10- to 12-year-old, male chimpanzees were used in a study that required repeated flexible fiberoptic bronchoscopic procedures. The combination of ketamine and inhalation anesthesia was satisfactory for these procedures. The gross anatomy of the airways of the chimpanzee resembled those of man more than those of the dog or rhesus monkey. The bronchoscope could be easily maneuvered into the main bronchi, lobar bronchi, and at least two branches of the lobar airways. Sublobar lavages were performed to obtain cells from the deep lung. Histologic examination of a lung showed that generous numbers of bronchial glands extended down to the tertiary bronchi in chimpanzees explaining the copius amounts of mucous observed during bronchoscopy.