Can J Vet Res
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Concentrations of 64% to 70% nitrous oxide (N2O) provide intra-operative analgesia. Clinically, pulse oximeter estimation (SpO2) of oxygen (O2) hemoglobin saturation (SaO2) was observed to decrease with N2O. Absorption atelectasis from breathing O2 was thought to decrease arterial partial pressure of O2 (PaO2) below 70 mmHg and reduce SaO2 and SpO2 when N2O was used. ⋯ The dog with the highest carboxyhemoglobin (2%) had an SaO2 of 96.8% (PaO2 = 93 mmHg). Carboxyhemoglobin and SaO2 changes were not clinically significant. Pulse oximetry did not reliably estimate SaO2 but N2O was not always a factor.
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Comparative Study
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. ⋯ 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.
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Hemorrhage is a major concern in patients undergoing hepatic surgery or in those with hepatic trauma. In these cases, employing traditional hemostatic strategies can be problematic due to the diffuse nature of hepatic hemorrhage and limited opportunities for direct hemostasis. This study assessed the efficacy of a bovine-derived thrombin solution, (BT), as a topical liquid agent to augment hemostasis and survival following severe hepatic hemorrhage in a rat model. ⋯ Rats were then monitored for 72 h, after which survivors were euthanized. There was no significant difference in survival time, percentage survival, intra-operative ABP or HR, or post-operative PCV between treatment groups. There is insufficient evidence to recommend BT as the sole therapy using this delivery method for mitigating severe hemorrhage from liver injury.
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Comparative Study
Prior determination of baseline minimum alveolar concentration (MAC) of isoflurane does not influence the effect of ketamine on MAC in rabbits.
The objective of this study was to compare the effect on the minimum alveolar concentration (MAC) of isoflurane when ketamine was administered either after or without prior determination of the baseline MAC of isoflurane in rabbits. Using a prospective randomized crossover study, 8 adult, female New Zealand rabbits were allocated to 2 treatment groups. Anesthesia was induced and maintained with isoflurane. ⋯ Minimum alveolar concentration (MAC) values did not differ significantly between the groups either during ketamine administration or after stopping ketamine. Under the study conditions, prior determination of the baseline isoflurane MAC did not alter the effect of ketamine on MAC. Both methods of determining MAC seemed to be valid for research purposes.
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Review
Hypercapnic respiratory acidosis: a protective or harmful strategy for critically ill newborn foals?
This paper reviews both the beneficial and adverse effects of permissive hypercapnic respiratory acidosis in critically ill newborn foals. It has been shown that partial carbon dioxide pressure (PCO2) above the traditional safe range (hypercapnia), has beneficial effects on the physiology of the respiratory, cardiovascular, and nervous system in neonates. In human neonatal critical care medicine permissive hypercapnic acidosis is generally well-tolerated by patients and is more beneficial to their wellbeing than normal carbon dioxide (CO2) pressure or normocapnia. ⋯ A search of online scientific databases was conducted to survey the literature on the effects of hypercapnia in neonates, with emphasis on newborn foals. The dynamic status of safety levels of PCO2 and data on the effectiveness of different carbon dioxide levels are not available for newborn foals and should be scientifically determined. Presently, permissive hypercapnia should be implemented or tolerated cautiously in compromised newborn foals and its use should be based on relevant data from adult horses and other species.