Critical incident technique analysis applied to perianesthetic cardiac arrests at a university teaching hospital.

OBJECTIVE: To apply the critical incident technique (CIT) methodology to a series of perianesthetic cardiac arrest events at a university teaching hospital to describe the factors that contributed to cardiac arrest. STUDY DESIGN: CIT qualitative analysis of a case series. ANIMALS: A group of 16 dogs and cats that suffered a perioperative cardiac arrest between November 2013 and November 2016. METHODS: If an arrest occurred, the event was discussed among the anesthesiologists. The discussion included a description of the case, a description of the sequence of events leading up to the arrest and a discussion of what could have been done to affect the outcome. A written description of the case and the event including animal signalment and a timeline of events was provided by the supervising anesthesiologist following discussion among the anesthesiologists. Only dogs or cats were included. After the data collection period, information from the medical record was collected. A qualitative document analysis was performed on the summaries provided about each case by the supervising anesthesiologist, the medical record and any supporting documents. Each case was then classified into one or more of the following: animal, human, equipment, drug and procedural factors for cardiac arrest. RESULTS: The most common factor was animal (n=14), followed by human (n=12), procedural (n=4), drugs (n=1) and equipment (n=1). The majority (n=11) of animals had multiple factors identified. CONCLUSIONS AND CLINICAL RELEVANCE: Cardiac arrests during anesthesia at a referral teaching hospital were primarily a result of animal and human factors. Arrests because of procedural, drug and equipment factors were uncommon. Most animals experienced more than one factor and two animals arrested after a change in recumbency. Future work should focus on root cause analysis and interventions designed to minimize all factors, particularly human ones.

Agreement among anesthesiologists regarding postoperative pain assessment in dogs.

OBJECTIVE: To establish evidence for the validity and reliability of three commonly used pain scales in dogs when assessed by video by specialists in anesthesia. STUDY DESIGN: Mixed-method test-retest observational study. SUBJECTS: A group of six American College of Veterinary Anesthesia and Analgesia board-certified specialists and 31 postoperative dogs. METHODS: The evaluators scored 31 dogs using a visual analogue scale (VAS), numeric rating scale (NRS), and Glasgow pain scale (GPS). The evaluators individually scored the dogs using all three scales together and subsequently, at 3 month intervals, using each of the scales apart. Then, all evaluators in one room reviewed 23 of the videos. A camera was positioned for video and audio recording of discussion about the videos. Intra- and interobserver reliability was determined using a two-way random model intra-class correlation coefficient (ICC). RESULTS: Linear regression indicated a strong correlation among all scales when assigned together (VAS versus NRS, p < 0.0001, R2 = 0.93; VAS versus GPS, p < 0.0001, R2 = 0.59; and NRS versus GPS, p < 0.0001, R2 = 0.61) and apart (VAS versus NRS, p < 0.0001, R2 = 0.68; VAS versus GPS, p < 0.0001, R2 = 0.40; and NRS versus GPS, p < 0.0001, R2 = 0.47). Posture, appearance, vocalization, stiffness, interaction between the animal and a person and response to palpation were identified as important variables for assessing pain. Intra-observer reliability produced average ICC values of 0.90 for VAS, 0.89 for NRS and 0.85 for GPS. Interobserver reliability produced average ICC values when scores were assigned together (VAS: 0.93, NRS: 0.93 and GPS: 0.93) and when done separately (VAS: 0.91, NRS: 0.93 and GPS: 0.95). CONCLUSIONS AND CLINICAL RELEVANCE: The preferred use of the VAS and NRS over the use of the GPS should be cautiously considered for research applications when experts are observers. Revisions of the GPS to clarify descriptors and remove or modify items that may not be associated with pain in dogs should be considered.

Effect of routine pre-anesthetic laboratory screening on pre-operative anesthesia-related decision-making in healthy dogs.

The usefulness of pre-anesthetic laboratory screening of healthy veterinary patients is controversial and clear evidence-based guidelines do not exist. The purpose of our study was to determine the influence of preanesthetic laboratory screening on peri-anesthetic plans in canine patients undergoing elective surgery. One hundred medical records were randomly selected between the years 2008 and 2013 and patient information was presented to 5 Diplomates of the American College of Veterinary Anesthesia and Analgesia (ACVAA) for review. They were given pre-anesthetic laboratory screening test results for each patient and asked whether the results would change the way they managed the case from an anesthesia perspective. Peri-operative anesthetic management was altered in 79% of patients based on pre-anesthetic screening results; however, the overall agreement among anesthesiologists was weak with 64% of changes made by only a single anesthesiologist. Pre-anesthetic laboratory screening test results may influence pre-operative anesthesia case management but major discrepancies can occur among ACVAA diplomates.

Effet du dépistage de laboratoire pré-anesthésique de routine sur la prise de décisions préopératoires liées à l'anesthésie chez des chiens en santé. L'utilité du dépistage de laboratoire pré-anesthésique des patients vétérinaires en santé est controversée et des lignes directrices claires basées sur des données probantes n'existent pas. Le but de notre étude consistait à déterminer l'influence du dépistage de laboratoire pré-anesthésique pour la péri-anesthésie chez les patients canins subissant une chirurgie non urgente. Cent dossiers médicaux choisis au hasard entre les années 2008 et 2013 et des données sur les patients ont été présentés à cinq diplomates de l'American College of Veterinary Anesthesia and Analgesia (ACVAA) aux fins d'examen. On leur a donné les résultats des tests de dépistage de laboratoire pré-anesthésiques pour chaque patient et on leur a demandé d'évaluer si les résultats auraient modifié la façon dont ils auraient géré le cas du point de vue de l'anesthésie. La gestion anesthésique péri-opératoire a été modifiée chez 79 % des patients en se basant sur les résultats du dépistage préanesthésique. Cependant, le consensus général parmi les anesthésiologistes était faible avec 64 % des changements apportés par seulement un seul anesthésiologiste. Les résultats des tests de dépistage de laboratoire pré-anesthésiques peuvent influencer la gestion des cas d'anesthésie préopératoire mais des écarts majeurs peuvent se produire parmi les diplomates de l'ACVAA.(Traduit par Isabelle Vallières).

Effects of orally administered enalapril on blood pressure and hemodynamic response to vasopressors during isoflurane anesthesia in healthy dogs.

OBJECTIVE: To examine whether preanesthetic administration of enalapril, compared with placebo, results in a greater decline in blood pressure (BP) or decreased responsiveness of BP to isotonic fluids or vasopressors in healthy dogs during isoflurane anesthesia. STUDY DESIGN: Randomized, experimental, placebo-controlled, blinded, crossover study. ANIMALS: Twelve healthy, female, purpose-bred beagles. METHODS: Dogs underwent the following week-long treatment protocols, each preceded by a 1 week washout period: oral placebo twice daily (PLA); oral enalapril, 0.5 mg kg(-1) twice daily, with the 15th dose withheld on the day of anesthesia (ENA-W), and oral enalapril, 0.5 mg kg(-1) twice daily, with the 15th dose administered 90 minutes prior to anesthetic induction (ENA). On day 8 of each treatment period, dogs were anesthetized in random order utilizing a standard protocol. Following stabilization at an end-tidal isoflurane concentration (Fe'Iso) of 1.3%, invasively measured systolic (SAP), diastolic (DAP) and mean (MAP) arterial blood pressure were continuously recorded via telemetry. Hypotension (SAP < 85 mmHg) was treated with the following sequential interventions: lactated Ringer's solution (LRS) bolus (10 mL kg(-1) ); repeated LRS bolus; dopamine (7 µg kg(-1)  min(-1) ); and dopamine (10 µg kg(-1)  min(-1) ) first without and then with vasopressin (1 mU kg(-1)  hour(-1) ). RESULTS: Compared with the PLA but not the ENA-W group, the ENA group had significantly lower average SAP, DAP and MAP at an Fe'Iso of 1.3%, spent more minutes in hypotension, and required a greater number of interventions to correct moderate-to-severe mean arterial hypotension. CONCLUSIONS: In healthy dogs, enalapril administered 90 minutes prior to isoflurane anesthesia increases the degree of intra-anesthetic hypotension and the number of interventions required to correct moderate-to-severe hypotension. CLINICAL RELEVANCE: Dogs receiving angiotensin-converting enzyme inhibitors on the day of anesthesia may exhibit clinically significant intra-anesthetic hypotension.

Perianesthetic development of diaphragmatic hernia in a horse with equine pituitary pars intermedia dysfunction (PPID).

A 21-year-old Thoroughbred gelding with a history of equine pituitary pars intermedia dysfunction (PPID) presented with priapism of 2 days' duration. The horse received a caudal morphine epidural and then underwent corpus cavernosum lavage and phallectomy under general anesthesia. The patient's recovery featured multiple unsuccessful attempts to stand and his respiratory distress persisted for several hours until he acutely developed severe colic and was euthanized. Necropsy findings revealed a pituitary adenoma of the pars intermedia, bilateral adrenal cortical hyperplasia, and diaphragmatic herniation. This report suggests that horses with PPID may present a greater risk for diaphragmatic hernia under general anesthesia or during procedures placing stress on the diaphragm, including anesthetic recovery.

Développement périanesthésique d'une hernie diaphragmatique chez un cheval atteint d'une dysfonction de l'hypophyse pituitaire (DHP). Un hongre Thoroughbred âgé de 21 ans avec une anamnèse de dysfonction de l'hypophyse pituitaire (DHP) a été présenté avec un priapisme présent depuis 2 jours. Le cheval a reçu une épidurale caudale de morphine et a ensuite subi un lavement du corps caverneux et une phallectomie sous anesthésie générale. Le rétablissement du patient a comporté de nombreuses tentatives infructueuses de se tenir debout et sa détresse respiratoire a persisté pendant plusieurs heures jusqu'à ce qu'il développe de graves coliques et soit euthanasié. Les constatations à la nécropsie ont révélé un adénome pituitaire de l'hypophyse, de l'hyperplasie corticale bilatérale et une herniation diaphragmatique. Ce rapport suggère que les chevaux atteints de DHP peuvent présenter un plus grand risque d'hernie diaphragmatique sous anesthésie générale ou durant des interventions exerçant un stress sur le diaphragme, y compris le réveil après l'anesthésie.(Traduit par Isabelle Vallières).

Development, implementation and impact of simple patient safety interventions in a university teaching hospital.

OBJECTIVE: To determine the incidence of anesthesia patient safety incidents at a university teaching hospital, develop interventions to address the most common incidents, and determine the effectiveness of these interventions. STUDY DESIGN: Pre-post intervention observational. ANIMALS: Four thousand, one hundred forty dogs and cats anesthetized by the anesthesia service. METHODS: The study was divided into two 11.5 month periods. During each period, incidents were logged (e.g. closed adjustable pressure limiting (APL) valve, esophageal intubation, and medication error). At the end of the first period, four countermeasures were incorporated into the service's protocols: 1) prior to any drug injection, the individual would read out aloud the drug name, patient name, and route of administration; 2) use of a uniquely colored occlusive wrap over arterial catheters; 3) a check box on the anesthesia record labeled "Technician Confirmed Intubation"; 4) a check box on the anesthesia record labeled "Technician Checked OR (operating room)". The number of patient safety incidents during period 1 and period 2 were compared using Fisher's Exact Test. RESULTS: During Period 1, there were 74 incidents documented in 2028 patients (3.6%) including 25 medication errors, 20 closed APL valves, and 16 of esophageal intubation. During Period 2, there were 30 incidents documented in 2112 patients (1.4%) including 14 medication errors, 5 closed APL valves, and 4 of esophageal intubation. The proportion of events during Period 2 was significantly smaller than during Period 1 (p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Implementation of four simple interventions was associated with a significant decrease in the number of incidents.

Effect of Hypotension and Dobutamine on Gastrointestinal Microcirculations of Healthy, Anesthetized Horses.

Horses undergoing abdominal exploratory surgery are at risk of hypotension and hypoperfusion. Normal mean arterial pressure is used as a surrogate for adequate tissue perfusion. However, measures of systemic circulation may not be reflective of microcirculation. This study measured the mean arterial pressure, cardiac index, lactate, and four microcirculatory indices in six healthy, anesthetized adult horses undergoing elective laparotomies. The microcirculatory parameters were measured at three different sites along the gastrointestinal tract (oral mucosa, colonic serosa, and rectal mucosa) with dark-field microscopy. All macro- and microcirculatory parameters were obtained when the horses were normotensive, hypotensive, and when normotension returned following treatment with dobutamine. Hypotension was induced with increases in inhaled isoflurane. The horses successfully induced into hypotension did not demonstrate consistent, expected changes in systemic perfusion or microvascular perfusion parameters at any of the three measured gastrointestinal sites. Normotension was successfully restored with the use of dobutamine, while the systemic perfusion and microvascular perfusion parameters remained relatively unchanged. These findings suggest that the use of mean arterial pressure to make clinical decisions regarding perfusion may or may not be accurate.

Pharmacodynamics of alfaxalone after single-dose intramuscular administration in red-eared sliders (Trachemys scripta elegans): a comparison of two different doses at two different ambient temperatures.

OBJECTIVE: This study compares the pharmacodynamics of two different doses of alfaxalone administered intramuscularly (IM) to red-eared sliders at two ambient temperatures. STUDY DESIGN: Prospective blinded crossover experimental study. ANIMALS: Nine adult female sliders (Trachemys scripta elegans). METHODS: Following a 2-week acclimation at 22-25 °C, nine sliders were randomly assigned to receive alfaxalone, 10 mg kg(-1) (W10), or 20 mg kg(-1) (W20) IM. Each turtle received each dose, with a minimum 7-day washout period. A blinded observer evaluated heart rate (HR), palpebral and corneal reflexes, muscle relaxation, handling, and response to toe pinch at the following points: pre-injection, and 5, 12, 20, 30, 45, 60, and 120 minutes post-injection. Turtles then acclimated to 18-20 °C for 63 days, and the experiment was repeated in this lower-temperature environment, with treatment groups C10 (alfaxalone 10 mg kg(-1)) and C20 (alfaxalone 20 mg kg(-1)) subjected to the same crossover design. RESULTS: C10 and C20 groups had significantly lower intraanesthetic HR than W10 or W20, respectively. C10 and W20 were significantly more relaxed and easier to handle than W10. No significant differences were observed in palpebral reflex, nor responsiveness to the toe pinch stimulus. None of the turtles lost corneal reflex. W20 and C20 had prolonged recoveries, compared to low-dose groups within the same temperature environment. Recovery was also longer at C20 and C10 compared to W10. CONCLUSIONS: Turtles given 10 mg kg(-1) were more relaxed and easier to handle in cold than warm conditions. Warm turtles were more relaxed and easier to handle when given 20 mg kg(-1) than those given 10 mg kg(-1). Cold conditions correlated with lower HR and longer recovery time for each dose category. CLINICAL RELEVANCE: The turtles had dose-dependent and inconsistent responses to alfaxalone. Lower ambient temperature augmented the behavioral effects of this drug.

A comparison of cardiopulmonary and anesthetic effects of an induction dose of alfaxalone or propofol in dogs.

OBJECTIVE: To compare the physiological parameters, arterial blood gas values, induction quality, and recovery quality after IV injection of alfaxalone or propofol in dogs. STUDY DESIGN: Prospective, randomized, blinded crossover. ANIMALS: Eight random-source adult female mixed-breed dogs weighing 18.7 ± 4.5 kg. METHODS: Dogs were assigned to receive up to 8 mg kg(-1) propofol or 4 mg kg(-1) alfaxalone, administered to effect, at 10% of the calculated dose every 10 seconds. They then received the alternate drug after a 6-day washout. Temperature, pulse rate, respiratory rate, direct blood pressure, and arterial blood gases were measured before induction, immediately post-induction, and at 5-minute intervals until extubation. Quality of induction, recovery, and ataxia were scored by a single blinded investigator. Duration of anesthesia and recovery, and adverse events were recorded. RESULTS: The mean doses required for induction were 2.6 ± 0.4 mg kg(-1) alfaxalone and 5.2 ± 0.8 mg kg(-1) propofol. After alfaxalone, temperature, respiration, and pH were significantly lower, and PaCO2 significantly higher post-induction compared to baseline (p < 0.03). After propofol, pH, PaO2 , and SaO2 were significantly lower, and PaCO2 , HCO3 , and PA-aO2 gradient significantly higher post-induction compared to baseline (p < 0.03). Post-induction and 5-minute physiologic and blood gas values were not significantly different between alfaxalone and propofol. Alfaxalone resulted in significantly longer times to achieve sternal recumbency (p = 0.0003) and standing (p = 0.0004) compared to propofol. Subjective scores for induction, recovery, and ataxia were not significantly different between treatments; however, dogs undergoing alfaxalone anesthesia were more likely to have ≥ 1 adverse event (p = 0.041). There were no serious adverse events in either treatment. CONCLUSIONS AND CLINICAL RELEVANCE: There were no clinically significant differences in cardiopulmonary effects between propofol and alfaxalone. A single bolus of propofol resulted in shorter recovery times and fewer adverse events than a single bolus of alfaxalone.

Is the Use of Protective Behavioral Strategies Associated With College Sexual Assault Victimization? A Prospective Examination.

Sexual assault protective behavioral strategies (PBS) may be negatively associated with sexual assault victimization. However, no studies to date have prospectively examined whether the use of sexual assault PBS is negatively associated with subsequent sexual assault experiences. The current study examined the association between the use of sexual assault PBS and subsequent sexual assault victimization severity. College women who reported engaging in heavy episodic drinking ( n = 77) were assessed online for their use of sexual assault PBS and history of sexual assault victimization. In addition, a 3-month follow-up survey was given assessing sexual assault victimization severity in the past 3 months. The use of sexual assault PBS was negatively associated with sexual assault severity in the 3-month follow-up period. Future research should further examine these PBS to create more college-specific PBS and to determine whether they are useful as risk-reduction strategies.

Comparison of the oral and rectal mucosal and colonic serosal microcirculations of healthy, anesthetized horses.

The objectives of the study were to: i) determine baseline microvascular perfusion indices (MPI) and assess their repeatability in healthy horses under general anesthesia, and ii) compare the MPIs of 3 microvascular beds (oral mucosa, colonic serosa, and rectal mucosa). Healthy adult horses were anesthetized and sidestream dark field microscopy was used to collect video loops of the oral mucosa, rectal mucosa, and colonic serosa under normotensive conditions without cardiovascular support drugs; videos were later analyzed to produce MPIs. Baseline MPI values were determined for each site, which included the total vessel density (TVD), perfused vessel density (PVD), portion perfused vessels (PPV), and microcirculatory flow index (MFI). Differences in MPIs between microvascular beds were not statistically significant. Repeatability of the measurements varied for each MPI. In particular, the site of sampling had a profound effect on the repeatability of the PPV measurements and should be considered in future studies.

Les objectifs de cet étude étaient: i) de déterminer les indices de perfusion microvasculaires (IPM) de base et évaluer leur répétabilité chez les chevaux en bonne santé sous anesthésie générale, et ii) de comparer les IPMs de trois lits microvasculaires (muqueuse orale, séreuse du colon, et muqueuse rectale). Des chevaux adultes en bonne santé ont été anesthésiés et une unité de microscopie au champ sombre a été utilisée pour recueillir des boucles vidéo de la muqueuse buccale, de la muqueuse rectale, et de la séreuse du colon sous des conditions de tension artérielle normale. Les vidéos ont été analysées pour produire les IPMs, incluant la densité totale des vaisseaux, la densité des vaisseaux perfusés, la portion des vaisseaux perfusés, et l'index de flux microcirculaire. Pour chaque IPM, les différences entre les sites anatomiques n'étaient pas significatives statistiquement. La répétabilité des mesures variait pour chaque IPM. En particulier, le type de lit microvasculaire a une influence profonde sur la répétabilité des mesures.(Traduit par les auteurs).

A survey of the use of arterial catheters in anesthetized dogs and cats: 267 cases.

OBJECTIVES: To describe the clinical practice of insertion of arterial catheters in anesthetized dogs and cats, to document complications of arterial catheterization, and to determine risk factors associated with the complications. DESIGN: Prospective clinical study and retrospective evaluation of medical records. SETTING: University teaching hospital. ANIMALS: Dogs (n = 251) and 13 cats anesthetized for clinical procedures with arterial catheters inserted for blood pressure monitoring. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Details of the animal and catheter were collected at the time of anesthesia. On the following day, the catheter site was palpated and observed for abnormalities and the medical records of all animals were reviewed retrospectively for complications. Details of catheter placement were available for 216 catheters: 158 catheters in a dorsal pedal artery, 50 catheters in the median caudal (coccygeal) artery, 6 in the median artery, and 1 each in a cranial tibial and lingual artery. Blood pressure was obtained from 200 catheters, and 12 catheters failed before the end of anesthesia. Postoperative observational data obtained from 112 catheters described a palpable arterial pulse at 73 sites and no pulse at 21 sites. No risk factor for arterial occlusion was identified. No complications resulting from arterial catheterization were noted in the medical records. CONCLUSIONS: Arterial catheterization resulted in loss of a peripheral pulse postoperatively in 21/94 (22.3%) of animals examined, although no evidence of tissue ischemia was noted in the medical records of any of the patients in this study. These results suggest that insertion of a catheter in the dorsal pedal or coccygeal arteries was not associated with a high risk for complications. However, the course of arterial occlusion postoperatively warrants further investigation.

Differences in Mental Health and Sexual Outcomes Based on Type of Nonconsensual Sexual Penetration.

Little is known based on the stratification and localization of penetration type of rape: oral, vaginal, and/or anal. The current study examined associations between type of rape and mental and sexual health symptoms in 865 community women. All penetration types were positively associated with negative mental and sexual health symptoms. Oral and/or anal rape accounted for additional variance in anxiety, depression, some trauma-related symptoms, and dysfunctional sexual behavior than the association with vaginal rape alone. Findings suggest that penetration type can be an important facet of a rape experience and may be useful to assess in research and clinical settings.

Updates in Perioperative Care: Ideas from the Human Field.

The article focuses mainly on appropriate patient preparation for an anesthetic episode. Special attention is given to evaluate the environmental situation for optimal adjustment to reduce stress before the anesthetic event. During the anesthetic event, special attention must be paid regarding monitoring and, evaluating the patient during and after the anesthetic episode.

The Use of Drinking and Sexual Assault Protective Behavioral Strategies: Associations With Sexual Victimization and Revictimization Among College Women.

Despite consistent high rates of campus sexual assault, little research has examined effective strategies to decrease sexual assault victimization. Sexual assault and drinking protective behavioral strategies (PBS) may be important means of reducing sexual assault victimization risk on college campuses but need further examination. The current study examined the relationship among sexual assault in childhood, before college, and since college to evaluate the mitigating roles of both sexual assault PBS and drinking PBS on sexual assault victimization. Participants (n = 620) were undergraduate women, 18 to 20 years old. The current study was a cross-sectional online survey assessing participants' sexual assault PBS and sexual assault history. Sexual assault history was positively associated with future sexual assault experiences. Pre-college sexual assault was associated with increased since-college sexual assault and increased drinks per week. Since-college adolescent/adult sexual assault was associated with less use of sexual assault PBS. These findings suggest that PBS may have an important role in sexual assault victimization and future research should examine their usefulness in risk reduction programs for college women.

A new rodent model of hind limb penetrating wound injury characterized by continuous primary and secondary hyperalgesia.

UNLABELLED: This article reports the development of a new hind limb pain model in which an incisional stab wound is placed on the front and back of the calf, causing both superficial and deep tissue injury. The injury causes primary mechanical hyperalgesia on the calf and secondary hind paw hyperalgesia, which served as the focus of the present study. Animals with unilateral stab wounds showed a significant increase in percent paw withdrawal (secondary mechanical hyperalgesia, reversed by morphine administration) from 2 to 48 hours after surgery, but no evidence of thermal hyperalgesia. In contrast, animals with bilateral leg injuries showed bilateral secondary mechanical and thermal hyperalgesia. Rats with unilateral leg incisional stab wounds showed a significant decrease in cage activity in both the horizontal and vertical directions, monitored by using a novel activity box approach, as compared to their 24-hour baseline levels or to the activity of naïve animals. Analysis of spinal cord Fos labeling demonstrated that calf injury significantly increased Fos expression in laminae I to VI of the L3-L5 cord segments. The data indicate that this model might be useful for evaluation of the mechanisms underlying penetrating injury-induced primary and secondary hyperalgesia or for testing the effect of analgesics on hyperalgesia induced by such injury. PERSPECTIVE: Stab wounds and other types of penetrating wounds routinely encountered in emergency rooms and clinics are accompanied by pain associated with superficial and deep tissue injury. Here we present a rodent stab wound model that affords an opportunity to study the mechanisms of pain associated with traumatic injury.

Effect of duration and type of anesthetic on tear production in dogs.

OBJECTIVE: To determine effects of duration and type of anesthetic on tear production in dogs. ANIMALS: 8 female Beagles. PROCEDURES: Each dog was randomly allocated into 1 of 4 groups according to a Latin square design to receive anesthesia as follows: 1 hour with isoflurane, 1 hour with desflurane, 4 hours with isoflurane, and 4 hours with desflurane. Each dog was anesthetized with the selected inhalant 4 times during a 4-week period, with at least 5 days separating anesthetic episodes. Aqueous tear production was measured via the Schirmer I tear test at baseline and 10 minutes, 30 minutes, and 1 hour after induction of anesthesia as well as 2, 3, and 4 hours after induction for the 4-hour groups. Tear production was also measured after the dogs were standing after recovery from anesthesia and 2, 10, and 22 hours after recovery from anesthesia. RESULTS: Aqueous tear production was significantly reduced in dogs during anesthesia and returned to baseline values immediately after recovery and until 10 hours after anesthesia in all treatment groups. Inhalant type and duration had no significant effect. Neither lateral recumbency nor left versus right eyes had a significant effect. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that inhalant anesthetics did not reduce tear production after anesthesia and that longer-duration anesthesia did not cause decreased tear production, compared with shorter-duration anesthesia.

Effects of acepromazine maleate or morphine on tear production before, during, and after sevoflurane anesthesia in dogs.

OBJECTIVE: To investigate the effects of acepromazine maleate and morphine on aqueous tear production before, during, and after sevoflurane anesthesia in dogs. ANIMALS: 6 mixed-breed dogs. PROCEDURES: In a Latin square study design, dogs underwent i.m. administration of morphine (1 mg/kg), acepromazine (0.05 mg/kg), or saline (0.9% NaCl) solution (0.05 mL/kg), followed by induction and maintenance of anesthesia with sevoflurane for 30 minutes. The protocol was repeated until all dogs had received all treatments, with a minimum of 7 days between anesthetic episodes. Aqueous tear production was measured via Schirmer tear test I before treatment (baseline); before anesthetic induction; 5, 10, 20, and 30 minutes after anesthetic induction; immediately once dogs recovered from anesthesia; and 2 and 10 hours after recovery. RESULTS: Aqueous tear production for all treatments was significantly lower 10, 20, and 30 minutes (but not 5 minutes) after anesthetic induction than at baseline, before anesthetic induction, at recovery, and 2 and 10 hours after recovery. Aqueous tear production was significantly higher after saline solution administration than after morphine administration at the preinduction measurement point and 2 hours after recovery. No other differences were detected among the 3 treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Aqueous tear production after anesthesia did not differ significantly from baseline values after any treatment following 30 minutes of sevoflurane anesthesia, suggesting premedication with morphine or acepromazine does not contribute to a decrease in lacrimation in these circumstances.