Evaluation of a novel, low-cost, 3D printed video laryngoscope with borescope in anesthetized Beagle dogs.

OBJECTIVE: To develop and evaluate a low-cost three-dimensional (3D)-printed video laryngoscope (VLVET) for use with a commercial borescope. STUDY DESIGN: Instrument development and pilot study. ANIMALS: A total of six adult male Beagle dogs. METHODS: The VLVET consisted of a laryngoscope handle and a Miller-type blade, and a detachable camera holder that attached to various locations along the blade. The laryngoscope and camera holder were 3D-printed using black polylactic acid filament. Dogs were premedicated with intravenous (IV) medetomidine (15 µg kg-1) and anesthesia induced with IV alfaxalone (1.5 mg kg-1). The VLVET, combined with a borescope, was used for laryngeal visualization and intubation. Performance was evaluated by comparing direct and video-assisted views in sternal recumbency. The borescope camera was sequentially positioned at 2, 4, 6, 8 and 10 cm from the blade tip (distanceLARYNX-CAM), which was placed on the epiglottis during intubation or laryngoscopy. At the 10 cm distanceLARYNX-CAM, laryngeal visualization was sequentially scored at inter-incisor gaps of 10, 8, 6, 4 and 2 cm. Laryngeal visualization scores (0-3 range, with 0 = obstructed and 3 = unobstructed views) were statistically analyzed using the Friedman's test. RESULTS: Under direct visualization, the 2 cm distanceLARYNX-CAM had a significantly lower score compared with all other distanceLARYNX-CAM (all p = 0.014) because the view was obstructed by the camera holder and borescope camera. With both direct and camera-assisted views, visualization scores were higher at inter-incisor gaps ≥ 4 cm compared with 2 cm (all p < 0.05). CONCLUSIONS AND CLINICAL RELEVANCE: During laryngoscopy and intubation, the VLVET and borescope facilitated both direct and video laryngoscopy at distanceLARYNX-CAM in Beagle dogs when inter-incisor gaps were ≥ 4 cm.

Endotracheal tube cuff rupture during anesthesia in 2 dogs.

A 15-year-old intact male dachshund dog weighing 4.3 kg and a 5-year-old intact male mixed-breed dog weighing 13.6 kg were referred for examination because of paraparesis and facial paralysis, respectively. Magnetic resonance imaging (MRI) of the thoracolumbar region and brain was performed. The dogs were premedicated with IV butorphanol, 0.2 mg/kg body weight (BW) and midazolam, 0.2 mg/kg BW. Anesthesia was induced with IV propofol, 4 to 5 mg/kg BW and maintained with sevoflurane in oxygen. The dachshund was orotracheally intubated with a 5.0-millimeter internal diameter endotracheal (ET) tube. During positioning in the MRI room, intermittent positive pressure ventilation (IPPV) was applied. The mixed-breed dog was orotracheally intubated with a 6.0-millimeter internal diameter ET tube. After inflation of the ET tube cuff, a leaking test was done by applying positive pressure ventilation. In both dogs, a distinct "popping" sound was heard when positive pressure was applied, after which air leakage from the cuff was evident. Failure to inflate the pilot balloon led to suspicion of a ruptured cuff. Reintubation was completed, both dogs remained stable during anesthesia, and no postanesthetic complications were observed. Rupture of both cuffs, which was visually confirmed, was thought to be caused by overinflation of the cuff, repeated sterilization of the ET tubes, and positive pressure ventilation. Repeated sterilization of ET tubes with ethylene oxide can alter the physical integrity of cuffs. Care should be taken not to overinflate ET tube cuffs, especially when they have been repeatedly sterilized, as cuff rupture may result in failure to provide adequate IPPV. Key clinical message: This report describes 2 cases in which ET tube cuff rupture was noted during anesthesia for MRI.

Rupture du ballonnet du tube endotrachéal pendant l'anesthésie chez 2 chiens. Un chien teckel mâle intact de 15 ans pesant 4,3 kg et un chien croisé mâle intact de 5 ans pesant 13,6 kg ont été référés pour examen en raison de paraparésie et de paralysie faciale, respectivement. Une imagerie par résonance magnétique (IRM) de la région thoraco-lombaire et du cerveau a été réalisée. Les chiens ont reçu une prémédication avec du butorphanol IV, 0,2 mg/kg de poids corporel (PC), et du midazolam, 0,2 mg/kg PC. L'anesthésie a été induite avec du propofol IV, 4 à 5 mg/kg de PC et maintenue avec du sévoflurane dans de l'oxygène. Le teckel a été intubé par voie orotrachéale avec un tube endotrachéal (TE) de diamètre interne de 5,0 millimètres. Lors du positionnement dans la salle d'IRM, une ventilation intermittente à pression positive (VIPP) a été appliquée. Le chien de race mixte a été intubé par voie orotrachéale avec un TE de 6,0 millimètres de diamètre interne. Après le gonflage du ballonnet du TE, un test d'étanchéité a été effectué en appliquant une ventilation à pression positive. Chez les deux chiens, un son distinct de « claquement ¼ a été entendu lorsqu'une pression positive a été appliquée, après quoi une fuite d'air du ballonnet est devenue évidente. Le fait de ne pas gonfler le ballon pilote a fait soupçonner une rupture du ballonnet. Une ré-intubation a été effectuée, les deux chiens sont restés stables pendant l'anesthésie et aucune complication post-anesthésique n'a été observée. La rupture des deux ballonnets, confirmée visuellement, aurait été causée par un surgonflage du ballonnet, une stérilisation répétée des TE et une ventilation à pression positive. La stérilisation répétée des TE avec de l'oxyde d'éthylène peut altérer l'intégrité physique des ballonnets. Il convient de veiller à ne pas surgonfler les ballonnets des TE, en particulier lorsqu'ils ont été stérilisés à plusieurs reprises, car la rupture du ballonnet peut entraîner l'incapacité de fournir une VIPP adéquate.Message clinique clé:Ce rapport décrit 2 cas dans lesquels une rupture du ballonnet du TE a été constatée lors d'une anesthésie pour IRM.(Traduit par Dr Serge Messier).

Evaluation of a rapid sequence induction technique in dogs with or without rocuronium.

OBJECTIVE: To determine, using a rapid sequence induction (RSI) technique, whether rocuronium improves the quality and speed of endotracheal intubation in healthy dogs. STUDY DESIGN: Randomized, crossover, experimental study. ANIMALS: Six adult intact male Beagles (12.3 ± 0.4 kg). METHODS: Dogs were premedicated with intravenous acepromazine (0.03 mg kg-1) and hydromorphone (0.1 mg kg-1). Ten minutes later, anesthesia was induced with intravenous propofol (2 mg kg-1 over 5 seconds), followed by saline (0.06 mL kg-1, CT group) or rocuronium (0.6 mg kg-1, RT group), with orotracheal intubation attempted after 45 seconds. Intubation time (IT) and conditions (IC) were assessed. PaO2, PaCO2, arterial blood pH and serum cortisol were obtained before and after RSI. After endotracheal intubation, saline (0.04 mL kg-1) or sugammadex (4 mg kg-1) were administered intravenously in CT or RT groups, respectively. Spontaneous ventilation restoration was noted. RESULTS: The IT was 54.3 ± 6.9 (mean ± SD) and 57.8 ± 5.2 seconds for CT and RT, respectively (p = 0.385). All laryngoscopies indicated good IC in both treatment groups. Heart rate was lower in CT group than in RT group (66 ± 16 versus 103 ± 39 beats minute-1, p = 0.016). PaCO2, pH, PaO2 and cortisol did not differ between treatments. Compared with baseline, PaCO2 increased from 47.7 ± 6.2 to 58.8 ± 5.8 (p < 0.001) and pH decreased from 7.35 ± 0.04 to 7.28 ± 0.04 (p = 0.003), independent of treatment. Dogs in both treatment groups returned to spontaneous ventilation within 30 seconds of RSI. CONCLUSIONS AND CLINICAL RELEVANCE: RSI resulted in respiratory acidosis without hypoxemia or increased cortisol. Rocuronium did not improve IT or IC. Spontaneous ventilation was observed immediately after administering saline or sugammadex. The co-administration of rocuronium showed no clinical benefits over propofol alone in RSI in healthy dogs.

A pilot study of skin stretching and blood circulation effects of dermal suctioning in dogs.

Dermal suctioning has been reported to yield effects similar to those of cupping therapy in humans and horses, including pain reduction, increased blood circulation, improved flexibility, and healing. However, there is a dearth of reported outcomes concerning cupping or dermal suctioning in dogs. In this study, we examined the physiological effects of dermal suctioning in dogs. Employing the Medicell MINI pro8 device, dermal suctioning was applied to the dorsal surfaces of eight healthy beagle dogs for 20 min. Metrics such as body surface temperature, rectal temperature, pulse rate, respiratory rate, and skin pinch test results were gauged. Seven healthy beagle dogs were used as controls, and the same measurements were performed without dermal suctioning. The results showed a significant increase in the body surface temperature and skin pinch test results after dermal suctioning. We believe that the elimination of torsion in the blood vessels and nerves in the shallow fascia positively affected the thermoregulatory mechanism, resulting in an increase in body surface temperature, and also improving skin flexibility. Thus, dermal suctioning promotes subcutaneous blood circulation and improves skin flexibility in dogs. Further research is needed to identify the mechanisms underlying the effects of dermal suctioning and evaluate the stress in dogs caused by the implementation of the process.

Radiographic and computed tomographic evaluation of tracheal diameter and length in kittens.

OBJECTIVE: To measure the tracheal diameter and length in kittens using radiography and CT and to evaluate the concordance between measurements obtained with these 2 modalities. ANIMALS: 15 kittens with an estimated age of 12 weeks and mean body weight of 1.49 kg. METHODS: Radiographic and CT images were retrospectively evaluated to measure tracheal lengths and diameters. Tracheal diameters were measured at 5 different sites (A [at the level of the C2-3 intervertebral disk space], B [at the level of the C4-5 intervertebral disk space], C [at the cranial end of the manubrium sterni], D [at the level of the second rib], and E [1 cm cranial to the carina]) along the trachea. The cross-sectional area and transverse and vertical diameter ratios were calculated for each measurement site. RESULTS: The cross-sectional area was largest at site A and decreased from site C to site E. Based on the vertical diameter ratio, the tracheal shape was most circular at sites A and E, whereas from sites B to D, it was elliptical. The vertical diameters of the trachea on radiography and CT did not differ statistically significantly. However, the tracheal length measured on radiography was approximately 6 mm longer than that measured on CT (P < .05). CLINICAL RELEVANCE: Using the first rib as an anatomical reference, the placement of a cuffed endotracheal tube is recommended in kittens. In emergency situations, regression equations based on body weight may be helpful in predicting tracheal diameters.

[Inhalation anesthesia in the cat: Development of cuff pressure when using nitrous oxide]. / Inhalationsanästhesie bei der Katze: Die Entwicklung des Cuffdrucks bei Verwendung von Lachgas.

OBJECTIVE: During inhalation anesthesia with nitrous oxide in oxygen the pressure in the cuff of the endotracheal tube may increase due to diffusion of nitrous oxide into the cuff. The aim of the study was to investigate the development of cuff pressure during nitrous oxide anesthesia under clinical conditions in feline patients and to identify possible influencing factors such as tube size and gas flow rate. MATERIAL AND METHODS: The prospective study included cats scheduled for inhalation anesthesia with nitrous oxide for a minimum duration of 60 minutes at the Department for Small Animals of the University of Leipzig. Cuff pressure was adjusted with a cuff manometer and its development was recorded. RESULTS: In total, the cuff pressure values of 24 cats were recorded. Animals were allocated into groups by tube size (ID 4.0 mm and ID 4.5 mm) and by fresh gas flow rate: low flow rate (0.6 l/min) and high flow rate (3 l/min). During anesthesia, cuff pressure increased over time, with statistical significance occurring from 45 minutes onwards in comparison to the initial cuff pressure (p=0.005). After 60 minutes, there was a mean cuff pressure increase of 3 cmH2O. Despite this moderate mean increase, highly variable pressure values up to 48 cmH2O in individual animals were recorded. No cat reached the termination criterion of 60 cmH2O cuff pressure. Effects of tube size (p=0.63) and flow rate (p=0.334) on the cuff pressure were not evident. CONCLUSION: After a period of 45 minutes of nitrous oxide administration, a significant increase in cuff pressure occurs in the cat. However, tube size and total gas flow rate do not seem to influence the cuff pressure development. CLINICAL RELEVANCE: When using nitrous oxide during inhalation anesthesia, regular cuff pressure evaluation and correction are necessary and hence recommended in feline patients. As individual pressure changes may be highly variable, no fixed recommendations for optimal management are possible.

DIAGNOSTIC IMAGING AND OROTRACHEAL INTUBATION IN CLINICALLY HEALTHY WILD SUNDA PANGOLINS (MANIS JAVANICA) IN SINGAPORE.

Pangolins are amongst the most overexploited species in the world and all eight species of pangolins are threatened with extinction. These animals are rare in zoological collections and often suffer high mortality rates in captivity. Maintaining healthy populations in captivity has become more important with the declining populations in the wild, but knowledge of veterinary care of these animals is limited. Interpreting radiography and ultrasonography images in a patient can be challenging without knowledge of normal findings. The Wildlife Healthcare and Research Center (WHRC) at Mandai Wildlife Reserve (MWR) admits an average of 25 Sunda pangolins (Manis javanica) annually, which is a Critically Endangered species native to Singapore. All the pangolins are triaged on admission and anesthetized for a health assessment before release into the wild. Endotracheal intubation using an otoscope and stylet is a novel technique in the species that has been developed and is commonly performed with these pangolins. A retrospective study was done on 20 clinically healthy wild pangolins to determine normal ultrasonography and radiography findings in the species. Notable findings include the presence of radio-opaque particles in the stomachs of all pangolins, the presence of free fluid cranial to the left kidney (13/20), a spleen with multifocal hypoechoic regions (6/20), and open epiphyseal plates of long bones even in large individuals weighing as heavy as 6.8 kg. Ultrasonographic images and measurements of kidney, spleen, and adrenal gland sizes as well as intestinal, gallbladder, and urinary bladder wall thickness were also described. These diagnostic imaging findings can advance the veterinary care of captive and wild pangolins.

Retrospective computed tomography analysis of endotracheal tube constriction and mispositioning in cats and dogs.

OBJECTIVE: To discover the prevalence of endotracheal tube (ETT) constriction and rostral and caudal mispositioning in anaesthetized cats and dogs, and to identify associated risk factors. STUDY DESIGN: Retrospective analysis. ANIMALS: A total of 146 cats and 670 dogs. METHODS: Computed tomography images of the head/neck/thorax from orotracheally intubated cats and dogs were visually assessed for constriction or mispositioning of the ETT. If constriction was present, measurements of the cross-sectional area (CSA) of the ETT lumen at constricted and un-constricted locations were compared. Location and cause of constriction were noted and the expected increase in resistance to gas flow was calculated. Animal information was collected from clinical records. Normality of continuous variables was assessed via the Shapiro-Wilk test. Chi-square tests examined associations between variables. Kendall's tau-b test was performed between measured ETT size and degree of constriction. RESULTS: The ETT extended rostrally beyond incisors in 52% of cases; the connector was within the oral cavity in 19% of cases. The ETT extended beyond the first rib in 25.5% of cases. The prevalence of ETT constriction was 22.7%. Median reduction in CSA was 7.68% (0.14-64.19%). Median increase in resistance assuming laminar and turbulent flow was 16.5% (0.3-680%) and 21% (0.3-1200%), respectively. The most common cause of constriction was the presence of a radiotherapy mouth gag. Significant associations existed between presence of constriction and rostral mispositioning, and caudal mispositioning and extreme brachycephaly. Increased severity of constriction was more likely in smaller ETT. CONCLUSIONS AND CLINICAL RELEVANCE: Constriction and mispositioning of ETT occurred very commonly in this population. Checking the ETT within the oral cavity for constriction and mispositioning is recommended. Radiotherapy mouth gags increase the risk of ETT compression. Smaller ETT are at greater risk of severe constriction. Brachycephalic dogs are at particular risk of caudal mispositioning.

A case of epiglottic entrapment in a cat.

OBJECTIVE: The objective of this study was to describe a case of epiglottic entrapment in a cat. CASE SUMMARY: A 5-month-old male neutered Russian Blue cat was evaluated for progressive stertorous upper airway sounds, acute onset vestibulopathy and abnormal laryngeal anatomy. Endotracheal intubation was only able to be achieved using videoscopic guidance and identified concern for severe nasopharyngeal stenosis. A computerized tomography scan revealed otitis interna, narrowed nasopharynx and no definitive cause for the stertorous breathing. The cat recovered very slowly from anaesthesia due to concern for airway obstruction following extubation. It was discharged the following day and then passed away at home 2 weeks later. Necropsy revealed that the epiglottis was obscured by 2 cm of redundant mucosal tissue extending from the base of the tongue to the larynx resulting in epiglottic entrapment. Also noted was chronic, severe otitis interna and externa. Upper airway obstruction is suspected to be the cause of sudden death. NEW OR UNIQUE INFORMATION: To the authors' knowledge, this is the first report of these oropharyngeal anatomic abnormalities in a cat.

Complications secondary to endotracheal intubation in dogs and cats: A questionnaire-based survey among veterinary anaesthesiologists.

OBJECTIVE: To investigate anaesthesiologists' attitudes towards endotracheal intubation and the perceived incidence of complications secondary to endotracheal intubation in dogs and cats. STUDY DESIGN: A cross-sectional online questionnaire-based study. METHODS: Using an online questionnaire distributed via electronic mail, the perceived incidence of complications secondary to endotracheal intubation in dogs and cats was investigated. Attitudes towards endotracheal intubation, average caseload and percentage of animals intubated were examined. The study population consisted of Diplomates, Residents, and residency trained members of the American and European Colleges of Veterinary An(a)esthesia and Analgesia. Univariate descriptive statistics were calculated. For each complication, a mean incidence score (MIS) was calculated, ranging from 1 (never) to 5 (always). Additionally, a Wilcoxon signed-rank test and binary regression analyses were performed. A p value ≤ 0.05 was considered significant. RESULTS: The overall response rate was 35.1%, with a completion rate of 26.6%. Most dogs and cats undergoing general anaesthesia were intubated. Endotracheal intubation was viewed as an integral part of modern anaesthesia. Significant differences were found in the incidence of 16 of the 24 examined complications between dogs and cats (p ≤ 0.001). The most frequently perceived complications were reported to be cuff leak (MIS 3.20) and coughing during intubation (MIS 3.10) in dogs, and coughing (MIS 3.01) and laryngeal spasm during intubation (MIS 2.91) in cats. Sociodemographic and practice-specific aspects did not appear to play a significant role in the reported incidence of complications. CONCLUSIONS AND CLINICAL RELEVANCE: Endotracheal intubation was considered a state-of-the-art technique by the respondents. It was associated with a perceived low incidence of major complications and more frequent minor ones. Differences between dogs and cats need to be accounted for. Considering the retrospective and self-reporting nature of this survey, true incidences might differ.

Effect of intravenous fentanyl on cough reflex and quality of endotracheal intubation in cats.

OBJECTIVE: To assess the effects of intravenous (IV) fentanyl on cough reflex and quality of endotracheal intubation (ETI) in cats. STUDY DESIGN: Randomized, blinded, negative controlled clinical trial. ANIMALS: A total of 30 client-owned cats undergoing general anaesthesia for diagnostic or surgical procedures. METHODS: Cats were sedated with dexmedetomidine (2 µg kg-1 IV), and 5 minutes later either fentanyl (3 µg kg-1, group F) or saline (group C) was administered IV. After alfaxalone (1.5 mg kg-1 IV) administration and 2% lidocaine application to the larynx, ETI was attempted. If unsuccessful, alfaxalone (1 mg kg-1 IV) was administered and ETI re-attempted. This process was repeated until successful ETI. Sedation scores, total number of ETI attempts, cough reflex, laryngeal response and quality of ETI were scored. Postinduction apnoea was recorded. Heart rate (HR) was continuously recorded and oscillometric arterial blood pressure (ABP) was measured every minute. Changes (Δ) in HR and ABP between pre-intubation and intubation were calculated. Groups were compared using univariate analysis. Statistical significance was set as p < 0.05. RESULTS: The median and 95% confidence interval of alfaxalone dose was 1.5 (1.5-1.5) and 2.5 (1.5-2.5) mg kg-1 in groups F and C, respectively (p = 0.001). The cough reflex was 2.10 (1.10-4.41) times more likely to occur in group C. The overall quality of ETI was superior in group F (p = 0.001), with lower laryngeal response to ETI (p < 0.0001) and ETI attempts (p = 0.045). No differences in HR, ABP and postinduction apnoea were found. CONCLUSIONS AND CLINICAL RELEVANCE: In cats sedated with dexmedetomidine, fentanyl could be considered to reduce the alfaxalone induction dose, cough reflex and laryngeal response to ETI and to improve the overall quality of ETI.

Retrospective comparison of the effects of laryngeal mask and endotracheal tube on some cardio-respiratory variables in pet rabbits undergoing anaesthesia for elective gonadectomy.

BACKGROUND: Endotracheal intubation in rabbits is challenging and supraglottic airway devices, such as laryngeal masks (LMA), represent an alternative as they are easy to insert, and do not stimulate the larynx requiring therefore a lighter plane of anaesthesia for their insertion and positioning than the endotracheal tubes. We investigated whether, compared to an endotracheal tube, the LMA can reduce the negative effects of general anaesthetics on some cardiovascular and respiratory parameters routinely monitored in rabbits anaesthetized for elective gonadectomy. The records of 21 adult mixed breed pet rabbits were collected retrospectively. Rabbits were divided in two groups based on the type of airway device used. A laryngeal mask secured the airway in group LMA (n = 11), and in group ETT (n = 10) an endotracheal tube was used. The amount of propofol used before successful insertion of the airway device was recorded. A pitot-based spirometer was connected and ventilatory variables were measured immediately after insertion. Pulse rate, non-invasive arterial blood pressure, haemoglobin oxygen saturation, respiratory rate, end-tidal carbon dioxide and volatile anaesthetic consumption were also monitored during the surgical procedure; extubation time was noted as well. RESULTS: The use of LMA required significantly less propofol (0.8 to 4 mg/kg) for insertion than the ETT (1.2 to 5.6 mg/kg), and the difference was statistically significant (P < 0.01). No differences were observed in ventilatory variables measured immediately after airway positioning. Intraoperatively, there were no differences between groups for respiratory and cardiovascular variables, and amount of isoflurane administered. In all rabbits mean and diastolic blood pressure progressively decreased during surgery. Mean extubation time was shorter in group LMA (6 ± 2 min) than group ETT (8 ± 3 min, P < 0.01). CONCLUSION: The airway device did not clinically affect the cardiovascular and respiratory variables during anaesthesia. Intraoperative hypoventilation was observed in most rabbits regardless of the device being used; therefore ventilatory support may be required. Rabbits with the laryngeal masks were extubated earlier.

Development and evaluation of an anatomically designed and 3D printed device to enhance orotracheal intubation success in rabbits by inexperienced veterinarians.

OBJECTIVE: To assess whether the use of a three-dimensional (3D) printed device enhances the success rate of orotracheal intubation in rabbits. STUDY DESIGN: Prospective, crossover randomized controlled trial. ANIMALS: A total of six mixed-breed rabbits. METHODS: A device to guide the endotracheal tube was designed based on computed tomography images and then manufactured using 3D printing. Rabbits were randomly assigned for intubation by two inexperienced veterinarians using the blind (BLI), borescope- (BOR) or device- (DEV) guided techniques. Success rate, number of attempts, time to success, injury scores and propofol dose were recorded and compared. Significance was considered when p < 0.05. RESULTS: Success rate was higher in DEV (58.3%) than in BLI (8.3%) (p < 0.023), but not different from that in BOR (41.6%). Total time until successful intubation was lower in DEV (45 ± 23 seconds) and BOR (85 ± 62 seconds) than in BLI (290 seconds; p < 0.006). Time for the successful attempt was lower for DEV (35 ± 10 seconds) and BOR (74 ± 43 seconds) than in BLI (290 seconds; p < 0.0001). The propofol dose required was lower for DEV (2.3 ± 1.2 mg kg-1) than for BLI (3.4 ± 1.6 mg kg-1) (p < 0.031), but not different from BOR (2.4 ± 0.9 mg kg-1). Number of attempts and oxygen desaturation events were not different among techniques (p < 0.051 and p < 0.326, respectively). Injury scores [median (range)] before and after attempts were different in BLI [0 versus 1 (0-3), p < 0.005] and BOR [0 (0-1) versus 1 (0-3), p < 0.002] but not in DEV [0 (0-2) versus 0 (0-3), p < 0.109]. CONCLUSIONS AND CLINICAL RELEVANCE: The device facilitated orotracheal intubation with a time similar to the borescope-guided technique but faster than the traditional blind technique.

Use of a gum elastic bougie in a cat with severe upper airway stenosis.

Background: Gum elastic bougie (GEB) is an airway management device for patients who are difficult to intubate and its use has been reported in human medicine. However, to our knowledge, no reports in veterinary medicine have described oxygenation using GEB. We describe a case in which GEB was used to maintain oxygenation in a cat with severe upper airway stenosis. Case Description: A 10-year-old neutered male domestic shorthair cat was diagnosed with a laryngeal tumor with severe upper airway stenosis. During anesthesia induction, the normal laryngeal structure could not be confirmed; orotracheal intubation was difficult, resulting in a "cannot intubate, cannot oxygenate" status. The GEB was inserted, making it possible to oxygenate the cat until a permanent tracheostoma could be created, but hypoventilation was noted. Conclusion: Although GEB are not useful for proper ventilation, they can be useful for temporary oxygenation in veterinary medicine when airway management is difficult.

Comparison of four endotracheal tube cleaning protocols in anesthetized dogs.

OBJECTIVE: To compare the efficacy of 4 cleaning protocols applied to endotracheal tubes (ETTs) collected from anesthetized dogs. SAMPLE: 100 ETTs (25 per protocol). PROCEDURES: A 10-question survey designed to determine ETT reuse and cleaning practices was distributed via email to a sample of veterinary anesthesiologists. Informed by survey results, 4 ETT cleaning protocols were selected for use in a prospective clinical study. Dogs were intubated with sterile polyvinyl chloride ETTs. At extubation, each ETT was cultured for bacterial growth, randomly assigned to 1 of 4 protocols [water scrub (P1), detergent scrub (P2), detergent scrub and chlorhexidine gluconate (CHG) soak (P3), or detergent scrub and bleach soak (P4)], and cultured again after drying. Bacterial genera were identified using mass spectrometry and 16s rRNA sequencing. Proportions of ETTs exhibiting no post-cleaning growth were compared between protocols using the Fisher exact test with Bonferroni correction. RESULTS: Half of survey respondents that reused ETTs did not sterilize them before reuse, cleaning methods varied widely, and no reported methods were evidence-based. After use, the number of ETTs exhibiting no post-cleaning bacterial growth were 15/25 (60%), 14/25 (56%), 20/25 (80%), and 17/25 (68%) for protocols P1, P2, P3, and P4, respectively. Pairwise comparisons did not reveal any statistically significant differences between protocols. CLINICAL RELEVANCE: In small animal patients, some veterinary anesthesiologists reuse ETTs without sterilization and cleaning protocols vary widely. No differences between the studied protocols were identified. Further research is necessary to identify a safe, efficacious ETT cleaning protocol for use in small animal practice.

Some cardiopulmonary effects of capnoperitoneum in anesthetized guinea pigs (Cavia porcellus): spontaneous ventilation versus intubation and mechanical ventilation.

OBJECTIVE: To compare cardiopulmonary variables and blood gas analytes in guinea pigs (Cavia porcellus) during anesthesia with and without abdominal carbon dioxide (CO2) insufflation at intra-abdominal pressures (IAPs) 4 and 6 mmHg, with and without endotracheal intubation. STUDY DESIGN: Prospective experimental trial. ANIMALS: A total of six intact female Hartley guinea pigs. METHODS: A crossover study with sequence randomization for IAP and intubation status was used. The animals were sedated with intramuscular midazolam (1.5 mg kg-1) and buprenorphine (0.2 mg kg-1) and anesthetized with isoflurane, and an abdominal catheter was inserted for CO2 insufflation. Animals with endotracheal intubation were mechanically ventilated and animals maintained using a facemask breathed spontaneously. After 15 minutes of insufflation, the following variables were obtained at each IAP: pulse rate, respiratory rate, rectal temperature, oxygen saturation, end-tidal CO2 (intubated only), peak inspiratory pressure (intubated only), noninvasive blood pressure and blood gas and electrolyte values, with a rest period of 5 minutes between consecutive IAPs. After 4 weeks, the procedure was repeated with the guinea pigs assigned the opposite intubation status. RESULTS: Intubated guinea pigs had significantly higher pH and lower partial pressure of CO2 in cranial vena cava blood (PvCO2) than nonintubated guinea pigs. An IAP of 6 mmHg resulted in a significantly higher PvCO2 (65.9 ± 19.0 mmHg; 8.8 ± 2.5 kPa) than at 0 (53.2 ± 17.2 mmHg; 7.1 ± 2.3 kPa) and 4 mmHg (52.6 ± 10.8 mmHg; 7.01 ± 1.4 kPa), mean ± standard deviation, with intubated and nonintubated animals combined. CONCLUSIONS AND CLINICAL RELEVANCE: Although the oral anatomy of guinea pigs makes endotracheal intubation difficult, capnoperitoneum during anesthesia induces marked hypercapnia in the absence of mechanical ventilation. An IAP of 4 mmHg should be further evaluated for laparoscopic procedures in guinea pigs because hypercapnia may be less severe than with 6 mmHg.

Effect of anaesthetic maintenance with isoflurane or propofol on ease of endoscopic duodenal intubation in dogs.

OBJECTIVE: To compare the ease of endoscopic duodenal intubation (EDI) in dogs during maintenance of general anaesthesia with isoflurane or propofol infusion. STUDY DESIGN: Prospective, randomized, partially blinded clinical trial. ANIMALS: A total of 22 dogs undergoing upper gastrointestinal tract endoscopy to include EDI were recruited. METHODS: Dogs were randomly assigned isoflurane (ISO; n = 10) or propofol (PROP; n = 11) for maintenance of general anaesthesia. Following anaesthetic premedication with intramuscular medetomidine (0.005 mg kg-1) and butorphanol (0.2 mg kg-1), general anaesthesia was induced with propofol, to effect, maintained with 1.5% (vaporizer setting) isoflurane in 100% oxygen or 0.2 mg kg-1 minute-1 propofol. The dose of both agents was adjusted to maintain general anaesthesia adequate for the procedure. Degree of sedation 20 minutes post-anaesthetic premedication, propofol induction dose, anaesthetist and endoscopist training grade, animal's response to endoscopy, presence of gastro-oesophageal and duodenal-gastric reflux, spontaneous opening of the lower oesophageal and pyloric sphincters, antral movement and time to achieve EDI were recorded. EDI was scored 1 (immediate entry with minimal manoeuvring) to 4 (no entry after 120 seconds) by the endoscopist, blinded to the agent in use. Data were tested for normality (Shapiro-Wilk test) and differences between groups analysed using independent t test, Mann-Whitney U test and Fisher's exact test as appropriate. RESULTS: There were no significant differences between groups for EDI score [median (interquartile range): 2 (3) ISO, 2 (3) PROP] or time to achieve EDI [mean ± standard deviation: 52.50 ± 107.00 seconds (ISO), 70.00 ± 196.00 seconds (PROP)]. Significantly more dogs responded to passage of the endoscope into the oesophagus in group PROP compared with group ISO (p = 0.01). CONCLUSIONS AND CLINICAL RELEVANCE: Maintenance of general anaesthesia with either isoflurane or propofol did not affect EDI score or time to achieve EDI.

Full-thickness endotracheal tube defect resulting in an anaesthetic circuit leak.

BACKGROUND: Loss of endotracheal tube (ETT) integrity secondary to dental damage is reported in the human literature. OBJECTIVE: To describe this problem in equine anaesthesia. STUDY DESIGN: Case report. CLINICAL SUMMARY: An 18-year-old Standardbred gelding presented out of hours with colic signs. Findings on clinical examination and pain refractory to analgesia meant that exploratory laparotomy was elected for. Prior to general anaesthesia (GA) leak testing of the anaesthetic machine was performed and the pilot balloon of the endotracheal tube (ETT) was inflated to confirm cuff integrity. Intermittent-positive pressure ventilation (IPPV) was initiated immediately following placement in dorsal recumbency and connection to the anaesthetic machine. During the inspiratory phase of IPPV, a loud gas leak was audible from the oropharynx and minimal thoracic excursion was observed, with repeated inflations of the ETT cuff unsuccessful at abolishing the leak. Due to suspicion of a defect within the silicone ETT itself, a support arm was used to abolish the curvature of the ETT, maintaining it in a straighter plane. This intervention abolished the leak allowing effective IPPV. After completion of GA, a close inspection of the ETT revealed a full-thickness laceration, thought to be a result of dental damage at an earlier date. MAIN LIMITATIONS: A single case is described. CONCLUSIONS: This report emphasises the importance of thorough inspection of the ETT prior to use to effectively secure the airway and enable IPPV provision in critical cases.

Dexmedetomidine decreases the 50% effective dose (ED50) of intravenous propofol required to prevent tracheal intubation response in Beagles.

OBJECTIVE: To determine the 50% effective dose (ED50) of intravenous propofol required for successfully preventing tracheal intubation response in Beagles co-induced with dexmedetomidine. ANIMALS: 36 adult male Beagles. PROCEDURES: The dogs were randomly assigned to either group D1, group D2, or group C (received 1 µg/kg, 2 µg/kg dexmedetomidine intravenously, or the same amount of normal saline as dexmedetomidine, 10 mL). The first dog in each group received 6 mg/kg of propofol for induction. The pump speed of propofol was 600 mL/h. The dosage varied with increments or decrements of 0.5 mg/kg based on the Dixon up-and-down method. The duration of eye-opening after propofol administration was recorded. Changes in heart rate (HR) and respiratory rate (RR) were recorded at 5 timepoints: after entering the operation room and prior to propofol administration (T1), 1 and 3 min after propofol administration (T2 and T3), 3 and 5 min after intubation (T4 and T5). RESULTS: The required ED50 of propofol that prevented tracheal intubation response in D1, D2, and C groups were 6.4 mg/kg (95% CI, 6.1 to 6.7 mg/kg), 5.8 mg/kg (95% CI, 5.67 to 6 mg/kg), and 8.3 mg/kg (95% CI, 8 to 8.5 mg/kg), respectively. The recovery time of group D2 was significantly longer than that of groups D1 and C (P < .05). The differences in HR among the 3 groups were significant from T2 up to T5 timepoint (P < .05). The differences in RR among the 3 groups were significant at T2 and T3 timepoints (P < .05). CLINICAL RELEVANCE: Dexmedetomidine pre-injection reduces the amount of propofol required for endotracheal intubation response in Beagles, thereby reducing the respiratory inhibition induced by propofol.