Anaesthetic Effects of Propofol, Ketamine and their Combination (Ketofol) as Total Intravenous Anaesthesia (TIVA) in Pigs

Background: Endotracheal intubation for inhalation anaesthesia in pigs is not considered a good anaesthetic method as it is technically difficult because of oral anatomy and the presence of excess tissues in the oropharyngeal region. Moreover, the major limitation of inhalation anaesthesia is that it requires the use of a cumbersome and costly anaesthetic machine, including a suitable breathing system and vaporizer and is the exposure of operating-room personnel to the pollution in the ambient air. Therefore, the present study was undertaken to evaluate the effect of propofol, ketamine and their combination ‘Ketofol’ as a TIVA in pigs. Methods: The study was conducted in eighteen piglets of either sex. The piglets were randomly divided into three groups with six animals in each group. All the three groups were premedicated with Atropine sulphate @ 0.04mg/kg body weight and Xylazine Hydrochloride @ 1mg/kg body weight I.M. and Medazolam @ 0.5mg/kg body weight I.M. with minimum forcible restraint as pre-anaesthetic. In group-I, propofol @ 5mg/kg body weight, in group-II, ketamine @ 5mg/kg body weight and in group-III, ketofol @ 4mg/kg body weight was administered intravenously for induction after 15 minutes of pre-anaesthetic administration. Surgical anaesthesia was maintained for 90 minutes in all three groups viz. group-I, group-II and group-III with propofol @ 2.5mg/kg, ketamine @ 2.5mg/kg and ketofol @ 2mg/kg body weight respectively by intermittent bolus injection (IBI) technique. Clinical and cardiopulmonary profiles were evaluated before administration of the anaesthetic agent (0 minutes) then at 15, 30, 60 and 90 minutes during and after administration of anaesthetic agents to evaluate their anaesthetic effect. Result: The study revealed that induction time (IT), duration of analgesia (DOA), duration of recumbency (DOR) and recovery time (RT) interval showed better result in the combination of ketamine and propofol group as compared to propofol and ketamine-induced individual group. The temperature and respiration rate was significantly decreased in all the groups at 30 minutes during TIVA whereas heart rate was significantly increased in all the groups at 15 minutes. The combination of ketamine and propofol group showed a consistent diastolic pressure and systolic pressure during the entire period of anaesthesia. The SPO2 in the ketamine-induced group showed a significant decrease (P less than 0.01) as compared to the propofol and ketofol group. It was concluded that the anaesthetic drug combinations resulted in smooth and uneventful induction with mild cardiopulmonary depressions and rapid recovery.

Evaluation of the Effect of the Inspired Oxygen Fraction on Blood Oxygenation during Inhalant Anaesthesia in Horses: A Systematic Review with Meta-Analysis

In anaesthetized horses, pronounced ventilation/perfusion mismatching often occurs. Several authors have investigated the effect of lower inspired oxygen fractions (FiO2) to reduce formation of absorption atelectasis. This systematic review compared the effects of low (<0.6) and high (>0.8) FiO2 on the arterial oxygen tension (PaO2), the alveolar-to-arterial oxygen tension difference (P(A-a)O2), and the PaO2/FiO2 ratio in horses during inhalation anaesthesia. Using the Systematic Review Protocol for Animal Intervention Studies, four experimental and one clinical investigations were deemed suitable for inclusion. A meta-analysis was performed on the four experimental studies. The PaO2 was significantly lower (p = 0.0007, mean difference −23.54 kPa, 95% CI −37.18, −9.90) with a lower FiO2. However, the P(A-a)O2 was also significantly lower (p < 0.00001, mean difference −20.80 kPa, 95% CI −26.28, −15.32) when using a low FiO2. For the PaO2/FiO2 ratio, only one study fitted the inclusion criteria, so no meta-analysis was performed. It is concluded that, while only a limited number of studies are available, the use of a higher FiO2 in horses during inhalation anaesthesia will result in higher levels of PaO2, but also a larger P(A-a)O2 difference. Further studies are needed to increase the level of evidence on this subject.

An inhalation anaesthesia approach for neonatal mice allowing streamlined stereotactic injection in the brain

Investigating brain function requires tools and techniques to visualise, modify and manipulate neuronal tissue. One powerful and popular method is intracerebral injection of customised viruses, allowing expression of exogenous transgenes. This technique is a standard procedure for adult mice, and is used by laboratories worldwide. Use of neonatal animals in scientific research allows investigation of developing tissues, and enables long-term study of cell populations. However, procedures on neonatal mice are more challenging, due to the lack of reliable methods and apparatus for anaesthesia of these animals. Here, we report an inhalation-based protocol for anaesthesia of neonatal (P0-2) mice, and present a custom 3D-printed apparatus for maintenance of anaesthesia during surgical procedures. This approach significantly enhances animal welfare and facilitates wider and simpler use of neonatal rodents in scientific research. Our optimised method of anaesthesia enables a rapid method of stereotactic injection in neonatal mice for transduction of brain tissue. We demonstrate this procedure for targeted labelling of specific brain regions, and in vivo modification of tissue prior to organotypic culture. This anaesthetic approach can be readily employed by any laboratory, and will enable safer use of neonatal rodents across a diverse spectrum of scientific disciplines.HighlightsDevelopment of inhalation-based anaesthesia for early postnatal (P0-2) mice3D-printed mould allows anaesthetic maintenance for neonatal surgeryImproved mouse welfare through reliable neonatal inhalation anaesthesiaRapid procedure for brain transduction of mouse litter in under 2 hours

Comparison of the Effects of Isoflurane and Sevoflurane General Anaesthesia after Induction by Propofol on Clinical and Physiological Measurements in Calves

Background: In veterinary surgical operations for cats and dogs, inhalation anaesthesia is known to be a good option for general anaesthesia in long operations or emergency cases. Studies have revealed that during inhalation anaesthesia, the heart and respiratory functions of the animals are more stable compared to injectable anaesthesia. However, there are few studies performed with the use of inhalation anaesthesia in ruminants. In this research, the goal is to evaluate the effects of isoflurane and sevoflurane after induction with propofol in calves based on clinical and physiological parameters and to find a more reliable strategy for general anaesthesia in ruminants.Materials, Methods & Results: The research was carried out on 30 calves, from new-born up to 3-months-old, undergoing surgery operation. Each group consisted of 15 animals that were divided as isoflurane and sevoflurane. For premedication, atropine was administered at a dose of 0.04 mg/kgvia subcutaneous injection in calves. For induction, 15 min after atropine application, propofol was given at 5-6 mg/kgvia intravenous infusion. Then, endotracheal intubation was performed and inhalation anaesthesia began at 5 min after induction. In the isoflurane group, the onset of anaesthesia concentration was set to 3-5% and the maintenance was set to a concentration of 1.5-3%. In the sevoflurane group, the onset of anaesthesia concentration was set to 5-7% and the maintenance was set to a concentration of 2.5-4%. To monitor the calves, the heart rate (HR), the pulse rate (PR), the systolic blood pressure (SBP), diastolic blood pressure (DBP), the respiratory rate (RR), the rectal temperature (RT) and the electrocardiogram (ECG) measurements were recorded before anaesthesia, the premedication, the induction periods, at 5, 15, 30, 45, 60, and 75 min after the onset of inhalation anaesthesia during the operation period. Blood samples were taken before anaesthesia, premedication, induction periods, at 30 and 75 min during the operation and the red blood cell (RBC) count, white blood cell (WBC) count, the amount of haemoglobin (HGB), the haematocrit concentration (HCT), and the platelet (PLT) count were evaluated. Based on the findings, isoflurane and sevoflurane suppressed the cardiovascular system minimally. Both anaesthetic agents caused decreases that did not exceed the physiological limits compared to the measurements taken before the initiation of anaesthesia. Although no significant differences were detected between the groups (P > 0.05) at clinical parameters, the RT differences were regarded as statistically significant according to the measurements that were taken before anaesthesia at all measurement times (P < 0.05). In both groups, the changes that occurred in the P wave, the PR interval, and in the QRS, R and T waves remained within the reference values given in the literature. Both anaesthetic agents have similar effects on the ECG. The dramatic no changes throughout anaesthesia in terms of the amount of HGB and HCT, the RBC, the WBC, and the PLT were not statistically significant, which may be associated with good tissue perfusion.Discussion: Since no serious complications occurred with either anaesthetic option, we have concluded that isoflurane and sevoflurane have similar effects on the cardiopulmonary systems of calves. In addition, the effects of propofol, which is used for induction, have been evaluated and observed and this drug is an effective and reliable option to initiate inhalation anaesthesia. The research on the use of this anaesthetic in calves is limited and most of the existing studies investigated its combination with injectable anaesthetics. As a result, in this research, we concluded that isoflurane and sevoflurane induce similar physiological measurement results, blood parameters, and ECG results and that both anaesthetics cause minimal complications.