Effects of PEEP on the relationship between tidal volume and total impedance change measured via electrical impedance tomography (EIT).

Electrical impedance tomography (EIT) is used in lung physiology monitoring. There is evidence that EIT is linearly associated with global tidal volume (VT) in clinically healthy patients where no positive end-expiratory pressure (PEEP) is applied. This linearity has not been challenged by altering lung conditions. The aim of this study was to determine the effect of PEEP on VT estimation, using EIT technology and spirometry, and observe the stability of the relationship under changing lung conditions. Twelve male castrated cattle (Steer), mean age 7.8 months (SD ± 1.7) were premedicated with xylazine followed by anaesthesia induction with ketamine and maintenance with halothane in oxygen via an endotracheal tube. An EIT belt was applied around the thorax at the level of the fifth intercostal space. Volume controlled ventilation was used. PEEP was increased in a stepwise manner from 0 to 5, 10 and 15 cmH2O. At each PEEP, the VT was increased stepwise from 5 to 10 and 15 mL kg-1. After a minute of stabilisation, total impedance change (VTEIT), using EIT and VT measured by a spirometer connected to a flow-partitioning device (VTSpiro) was recorded for the following minute before changing ventilator settings. Data was analysed using linear regression and multi variable analysis. There was a linear relationship between VTEIT and VTSpiro at all levels of PEEP with an R2 of 0.71, 0.68, 0.63 and 0.63 at 0, 5, 10 and 15 cmH2O, respectively. The variance in VTEIT was best described by peak inspiratory pressure (PIP) and PEEP (adjusted R2 0.82) while variance in VTSpiro was best described by PIP and airway deadspace (adjusted R2 0.76). The relationship between VTEIT and VTSpiro remains linear with changes in tidal volume, and stable across altered lung conditions. This may have application for monitoring and assessment in vivo.

The use of electrical impedance tomography (EIT) to evaluate pulse rate in anaesthetised horses.

Electrical impedance tomography (EIT) provides clinically useful lung images; however, it would be an advantage to extract additional cardiovascular information from the data. The aim of this study was to evaluate if cardiac-related changes measured by EIT can be used to measure pulse rate (PR) under physiological as well as high and low blood pressure states in anaesthetised horses. Electrical impedance tomography data and PR from seven horses anaesthetised in dorsal recumbency were recorded over 1 min during mechanical ventilation and 1 min of apnoea. Data were collected at four measurement time points; before and during intravenous administration of nitroprusside and phenylephrine, respectively. Nine pixels, estimated to represent the heart, were chosen from the EIT image. A novel algorithm detected peaks of impedance change for these pixels over 10 s intervals. Concurrent PR measured using an invasive blood pressure trace, was recorded every 10 s. EIT- and pulse-rate data were compared using Bland-Altman assessment for multiple measurements on each horse. Overall, 288 paired datasets from six of seven horses were available for analysis. There was excellent agreement for baseline measurements, as well as during hypertension and hypotension, with a bias of -0.26 and lower and upper limit of agreement at -2.22 (95% confidence intervals [CI], -2.89 to -1.86) and 1.69 (95% CI, 1.34-2.36) beats per min, respectively. EIT can be used to evaluate PR using cardiac-related impedance changes. More work is required to determine bias that might occur in anaesthetised horses in other recumbencies or clinical situations.

Joint impact of common risk factors on incident dementia: A cohort study of the Swedish Twin Registry.

BACKGROUND: As common risk factors of dementia, nine factors (low education, hearing loss, obesity, hypertension, smoking, depression, physical inactivity, diabetes and social isolation) were proposed. However, the joint impact of these factors on incident dementia is still uncertain; hence, we aimed to examine this impact. METHODS: We conducted a cohort study of 9017 cognitively intact individuals aged ≥ 65 years in the Swedish Twin Registry. The main exposure was the total number of reported risk factors (ranging from 0 to 9). Data on dementia diagnoses were based on clinical workup and national health registers. After estimating the adjusted hazard ratios of incident dementia, the population attributable fraction (PAF) was calculated. We then conducted additional analyses, including APOE ε4 status in a genotyped subsample (n = 2810) to check the relative impact of the main exposure and discordant twin pair (n = 1158) analysis to consider confounding by familial effects (shared genetic or familial environmental factors). RESULTS: The number of dementia cases was 1950 (21.6%). A dose-response relationship between the number of risk factors and incident dementia was observed; hazard ratio (95% confidence interval) per one-unit increment in number of risk factors was 1.07 (1.03 to 1.11). The PAF for the combination of the nine risk factors was 10.4%. The PAF of all nine risk factors was smaller than that of APOE ε4 genotype (20.8%) in the subsample. Discordant pair analysis suggested that the observed association was not likely explained by familial effects. CONCLUSION: The nine risk factors may have considerable impact as modifiable factors on incident dementia.

Restoration of arterial oxygen tension in horses recovering from general anaesthesia.

BACKGROUND: Arterial hypoxaemia is common in anaesthetised horses, but little information exists regarding restoration of arterial oxygen tension (PaO2 ) during recovery from anaesthesia, or if intra-operative management factors exert any longer-term effect. OBJECTIVES: To evaluate PaO2 in horses recovering from general anaesthesia up to 1 h after resuming standing. STUDY DESIGN: Prospective observational clinical cohort study. METHODS: Systemically healthy adult horses undergoing inhalational general anaesthesia for elective surgical procedures were studied. Arterial blood samples were obtained anaerobically prior to pre-anaesthetic medication, at end of anaesthesia, immediately following positioning in the recovery box, then at 10-min intervals until standing. Additionally, samples were taken when horses achieved sternal recumbency, at standing (STAND) and 1 h after standing (STAND+1). Data were analysed using ANOVA and mixed-effects linear regression, with significance set at P<0.05. RESULTS: Data from one hundred and two horses were analysed. Forty horses received controlled mandatory ventilation (CMV) throughout anaesthesia, 47 breathed spontaneously (SV) and 15 initially breathed spontaneously before CMV was imposed (S-CMV). Overall, PaO2 , P(A-a)O2 and PaCO2 remained significantly lower than baseline at STAND+1 (P<0.01). CMV resulted in higher PaO2 at the end of anaesthesia (P = 0.03) and during early recovery (P<0.01) than SV. Only in group S-CMV did PaO2 , P(A-a)O2 and PaCO2 return to baseline values at STAND+1. Highest PaO2 values associated with CMV were also associated with early recovery apnoea. MAIN LIMITATIONS: Non-standardised anaesthetic management, temporal and quantitative variation in oxygen delivery during early recovery and lack of control group where oxygen was electively withheld during recovery. CONCLUSIONS: Controlled mandatory ventilation results in better pulmonary function in horses as assessed by PaO2 , P(A-a)O2 and PaCO2 , an effect enhanced by an initial period of SV and still evident 1 h after standing. High PaO2 values may contribute to early recovery apnoea but this does not adversely affect outcome. The Summary is available in Portuguese - see Supporting Information.

Monitoring of tidal ventilation by electrical impedance tomography in anaesthetised horses.

BACKGROUND: Electrical impedance tomography (EIT) is a method to measure regional impedance changes within the thorax. The total tidal impedance variation has been used to measure changes in tidal volumes in pigs, dogs and men. OBJECTIVES: To assess the ability of EIT to quantify changes in tidal volume in anaesthetised mechanically ventilated horses. STUDY DESIGN: In vivo experimental study. METHODS: Six horses (mean ± s.d.: age 11.5 ± 7.5 years and body weight 491 ± 40 kg) were anaesthetised using isoflurane in oxygen. The lungs were mechanically ventilated using a volume-controlled mode. With an end-tidal carbon dioxide tension in the physiological range, and a set tidal volume (VTvent ) of 11-16 mL/kg (baseline volume), EIT data and VT measured by conventional spirometry were collected over 1 min. Thereafter, VTvent was changed in 1 L steps until reaching 10 L. After, VTvent was reduced to 1 L below the baseline volume and then further reduced in 1 L steps until 4 L. On each VT step data were recorded for 1 min after allowing 1 min of stabilisation. Impedance changes within the predefined two lung regions of interest (EITROI ) and the whole image (EITthorax ) were calculated. Linear regression analysis was used to assess the relationship between spirometry data and EITROI and EITthorax for individual horses and pooled data. RESULTS: Both EITROI and EITthorax significantly predicted spirometry data for individual horses with R2 ranging from 0.937 to 0.999 and from 0.954 to 0.997 respectively. This was similar for pooled data from all six horses with EITROI (R2 = 0.799; P<0.001) and EITthorax (R2 = 0.841; P<0.001). MAIN LIMITATIONS: The method was only tested in healthy mechanically ventilated horses. CONCLUSIONS: The EIT can be used to quantify changes in tidal volume.

Maintenance of equine anaesthesia over the last 50 years: Controlled inhalation of volatile anaesthetics and pulmonary ventilation.

In the first edition of this journal, Barbara Weaver wrote a review titled 'Equine Anaesthesia', stating that, at that time, it was quickly becoming accepted practice that many horses were being anaesthetised 'by essentially similar procedures, i.e. premedication, induction and then maintenance by controlled inhalation'. To celebrate the 50th anniversary of the first edition of this journal, this review covers the development of understanding and practice of inhalational anaesthesia and controlled ventilation in horses over the last 50 years. We review how the perceived benefits of halothane led to its widespread use, but subsequently better understanding of halothane's effects led to changes in equine anaesthetic practice and the utilisation of different inhalation agents (e.g. isoflurane and sevoflurane). We discuss how more recently, better understanding of the effects of the 'newer' inhalation agents' effects has led to yet more changes in equine anaesthetic practice, and while, further new inhalation agents are unlikely to appear in the near future, further enhancements to anaesthetic practice may still lead to improved outcomes. We review advances in our understanding of the anatomy and pathophysiology of the equine lung as well of the effects of anaesthesia on lung function and how these predispose to some of the common problems of gas exchange and ventilation during anaesthesia. We identify the aims of optimal mechanical ventilation for anaesthetic management and whether the various methods of ventilatory support during equine anaesthesia achieve them. We also highlight that further developments in equipment and optimal ventilator modes are likely in the near future.

Effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses.

REASONS FOR PERFORMING STUDY: The intestinal microbiota is important for health and disease. Factors that disturb the equine intestinal microbiota need further investigation. OBJECTIVES: To determine the effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses using next-generation sequencing. STUDY DESIGN: Experimental trial. METHODS: Faecal samples were taken from 8 horses at baseline, after transport, 12 h of fasting and 24, 48 and 72 h after a 6 h anaesthesia. Next generation sequencing of the V4 region of the 16S rRNA gene was used to assess the microbial composition of faeces. Alpha diversity, phylogenetic structures and beta diversity were assessed. RESULTS: There were significant changes in the relative abundances of phyla, classes, orders and families after transport, fasting and anaesthesia. Most notably horses had a significantly lower abundance of Clostridiales after transport compared with baseline (P = 0.03) and a decreased abundance of Rickettsiales after fasting (P = 0.024). Alpha diversity was not significantly different between time points (all P>0.21). When parsimony analysis was applied, anaesthesia had a significant effect on community membership and structure (Jaccard index and Yue and Clayton index both P = 0.02). CONCLUSIONS: There was some effect of transport, fasting and anaesthesia on the composition and structure of the microbiota of healthy horses. This indicates these are potentially stress factors for the equine intestinal microbiota. Further investigation is required to look at the potential impact of changes in the microbiota on the development of disease in the post anaesthetic period.

Predictors of continued playing or singing--from childhood and adolescence to adult years.

AIM: Many individuals play an instrument or sing during childhood, but they often stop later in life. This study surveyed adults representative of the Swedish population about musical activities during childhood. METHODS: We asked 3820 adults (65% women) aged from 27 to 54 from the Swedish Twin Registry, who took extra music lessons to those provided at school, to fill in a web-based questionnaire. Factors analysed were the age they started studying music, the instrument they played, kind of teaching, institution and educational content, number of lessons and perceived characteristics of the lessons, the music environment during their childhood years and their preferred music genre. All variables were dichotomised. RESULTS: Factors strongly associated with continued playing or singing were male sex, young starting age, cultural family background, self-selected instrument, attending music classes and more than once a week, church-related or private education, pop, rock or classical music, playing by ear and improvisation. CONCLUSION: Several significant predictors determined whether a child continued to sing or play an instrument as an adult and many could be externally influenced, such as starting at a young age, taking music classes more than once a week, improvisation and the type of music they played.

Oxygenation and ventilation characteristics in obese sedated dogs before and after weight loss: a clinical trial.

This prospective clinical study examined the effect of obesity and subsequent weight loss on oxygenation and ventilation during deep sedation in pet dogs. Data from nine dogs completing a formalised weight loss programme were evaluated. Dual-energy X-ray absorptiometry (DEXA) was used to quantify body fat mass prior to and after weight loss. Dogs were deeply sedated and positioned in dorsal recumbency. Sedation was scored using a semi-objective scheme. As part of the monitoring of sedation, arterial oxygen partial pressure (PaO2) and arterial carbon dioxide partial pressure (PaCO2) were measured after 10 min in dorsal recumbency. Oxygen saturation of haemoglobin (SpO2) was monitored continuously using pulse oximetry, starting oxygen supplementation where indicated (SpO2<90%) via a face mask. Morphometric measurements were taken from DEXA images and compared before and after weight loss. Several oxygen indices were calculated and correlated with body fat variables evaluated by DEXA. All body fat variables improved significantly after weight loss. PaO2 increased from 27.9±19.2 kPa to 34.8±24.4 kPa, while FiO2 decreased from 0.74±0.31 to 0.66±0.35. Morphometric measurements improved significantly after weight loss. PaO2/FiO2 (inspired oxygen fraction) and Pa/AO2 (ratio of PaO2 to alveolar PO2) also improved significantly, but there was no change in f-shunt and PaCO2 after weight loss. On multiple linear regression analysis, all oxygen indices were negatively associated with thoracic fat percentage. In conclusion, obesity decreases oxygenation in dogs during deep sedation. Oxygenation status improves with successful weight loss, but ventilation is not influenced by obesity.

Use of continuous positive airway pressure (CPAP) to optimise oxygenation in anaesthetised horses--a clinical study.

REASONS FOR PERFORMING STUDY: Hypoxaemia is a common problem during equine anaesthesia. Continuous positive airway pressure (CPAP) is a ventilation mode routinely employed in man to overcome hypoxaemia but has not been objectively assessed in horses. OBJECTIVES: To test the effects of CPAP on oxygenation and its indices in anaesthetised horses in a clinical setting. METHODS: Twenty-four healthy horses requiring anaesthesia in dorsal recumbency were anaesthetised using a standard protocol. Following orotracheal intubation and connection to an anaesthetic machine capable of applying CPAP, horses were randomly allocated to ventilate at physiological airway pressure measured at the airway opening (Group PAP) or to receive CPAP of 8 cmH2O (Group CPAP). Arterial blood gas analysis was performed as soon as arterial cannulation was achieved and 30, 60 and 90 min after induction. If PaCO2 increased above 9.31 kPa controlled ventilation was initiated. Groups were compared using a general linear model. RESULTS: Horses receiving CPAP had significantly higher PaO2 and calculated oxygen indices than horses receiving PAP. No significant differences in ventilation indices were observed between the 2 groups. Eight horses receiving PAP and 5 receiving CPAP required controlled ventilation. No differences in dobutamine requirements or mean arterial pressures were recorded. CONCLUSIONS: Continuous positive airway pressure of 8 cmH2O improved oxygenation indices in dorsally recumbent horses without significantly influencing ventilation. POTENTIAL RELEVANCE: Continuous positive airway pressure reduces the incidence of hypoxaemia in anaesthetised horses. Further research is warranted to elucidate the effects of CPAP on the cardiovascular system.

Volumetric capnography curves as lung function test to confirm bronchoconstriction after carbachol challenge in sedated dogs.

This study investigated volumetric capnography (VC) in detecting airway responsiveness following airway challenge using carbachol in seven sedated dogs via face mask. Nebulised saline was administered, followed by increasing concentrations of nebulised carbachol until airflow limitation occurred (EP). Dead space (DS) variables and shape indices of the VC curve were calculated automatically after entering arterial carbon dioxide tension. Airway DS, airway DS to tidal volume (VT) ratio and the intercept of slope 2 of the VC curve decreased significantly at EP by 10%, 13% and 16%, respectively, minute ventilation, VT and alveolar DS increased significantly at EP by 49%, 22% and 200%, respectively. We conclude that VC and derived indices may be used to verify a reaction to airway challenge caused by carbachol in sedated dogs.

Reversal of profound rocuronium or vecuronium-induced neuromuscular block with sugammadex in isoflurane-anaesthetised dogs.

This study evaluated the use of sugammadex for reversal of profound neuromuscular blockade induced with rocuronium or vecuronium in dogs. Anaesthesia was induced and maintained with isoflurane in oxygen in eight dogs on two occasions. Neuromuscular blockade was monitored using peroneal nerve stimulation and acceleromyography. Rocuronium 0.6 mg/kg or vecuronium 0.1mg/kg was administered intravenously (IV), followed 5 min later by sugammadex 8 mg/kg IV. Lag and onset time of rocuronium and vecuronium, lag time from sugammadex injection to recovery of first twitch response, recovery of T1/T0 to 25% and 75%, recovery index, and time to recovery of the train-of-four ratio (T4/T1) to 0.9 were recorded. Cardiovascular and respiratory parameters were also noted. Statistical analysis was performed using one-way ANOVA. Onset time for rocuronium (37 ± 18s; [mean ± SD]) was significantly shorter than for vecuronium (62 ± 15s) (P<0.04). No other significant differences were found between the two groups. After both rocuronium and vecuronium blockade, T4/T1 recovered to 0.9 in under 2 min after sugammadex (58.1 ± 67.8s and 98.1 ± 70.3s, respectively; P<0.32). Sugammadex can reverse profound neuromuscular blockade induced by vecuronium or rocuronium safely and rapidly in isoflurane-anaesthetised dogs.

The use of an acoustic device to identify the epidural space in cattle.

Twelve healthy cattle (weighing 188-835 kg) were placed in stocks and sedated with xylazine. Caudal epidural puncture was performed using an acoustic device that indicated a decrease in resistance with a change in pitch. Lidocaine was injected to verify correct needle placement by assessing needle prick stimuli applied on the left and right side of the tail root and the perineal region, and the loss of tail and anal sphincter tone. Pressure measurements were recorded during penetration of the different tissue layers and in the epidural space. A clear and sudden decrease in the pitch of the acoustic signal was audible in all 12 cattle. All cows showed clinical effects indicating successful epidural anaesthesia. The pressure in the epidural space after puncture was -19±10 mm Hg. The device may be of assistance in identifying the epidural space in cattle.

A cadaver study comparing two approaches to perform a maxillary nerve block in the horse.

REASONS FOR PERFORMING STUDY: Anaesthesia of the maxillary nerve of the horse has been described using several approaches, but sparse data exist to evaluate the accuracy of these methods. OBJECTIVES: This study compared 2 previously described approaches to the maxillary nerve to assess their relative accuracies. METHODS: Thirty severed heads from horse cadavers were arranged to approximate the position of a live horse. Methylene blue (0.25 or 0.1 ml) was injected using a 19 gauge 90 mm spinal needle by one of 2 approaches, the method used being randomly allocated in each instance. Method ANG: angulated needle insertion on the ventral border of the zygomatic process of the temporal bone and directed rostromedially. Method PER: needle inserted perpendicular to the skin surface, ventral to the zygomatic process of the malar bone, level with the temporal canthus of the eye. Accuracy of dye deposition was assessed following dissection. Placement was categorised as 'full hit' (complete nerve coverage or dye deposition centred on nerve), 'partial hit' (partial nerve discolouration but dye not centred on nerve) or 'miss' (no nerve discolouration). Deposition of dye relative to the nerve and whether injection was performed on the left or right side of the head was recorded. A Chi-squared test was performed to examine the relationship between the 2 methods. RESULTS: Method ANG was performed 31 times, Method PER 28 times. Full hits were 10/31 (32%) vs. 9/28 (32%), partial hits 15/31 (49%) vs. 14/28 (50%) and misses 6/31 (19%) vs. 5/28 (18%) (Methods ANG vs. PER, respectively). RESULTS were not statistically significantly different between the methods. Dye was deposited in the deep facial vein once by each method. Bone was contacted consistently with Method PER and 8/31 times with Method ANG. CONCLUSION AND CLINICAL RELEVANCE: Both methods appeared equivalent in terms of accuracy. Aspiration should always precede injection.

Reversal of profound rocuronium block monitored in three muscle groups with sugammadex in ponies.

BACKGROUND: This clinical study evaluated the speed of reversal of profound rocuronium block in ponies using sugammadex and investigated the differences in onset and recovery from block in three different muscle groups. METHODS: Anaesthesia was induced and maintained with isoflurane in oxygen 100% in eight ponies. Neuromuscular monitoring was performed at each site using acceleromyography: in the extensor muscles of the pelvic limb (peroneal nerve) and thoracic limb (radial nerve), and in the orbicularis oris muscle (OOM; facial nerve). Rocuronium 0.6 mg kg(-1) i.v. was administered, followed 5 min later by sugammadex 4 mg kg(-1) i.v. Onset time (onsetROC), maximum block, and time to recovery of the train-of-four ratio to 0.9 (TOFR=0.9) were recorded. The differences between monitored sites were compared using one-way anova followed by a post hoc Dunn's test. RESULTS: Onset of ROC was significantly delayed in OOM compared with both limbs [pelvic limb, thoracic limb, and OOM: 43.1 (sd 16.9), 50.6 (15.9), and 204.4 (35.8) s, respectively; P<0.001]. Complete block was achieved in the pelvic and thoracic limbs, but in none of the eight ponies in the OOM [mean T1=15.3 (9.4)%; range: 7-36%]. No differences were observed between muscle sites in recovery to TOFR=0.9 [pelvic limb, thoracic limb, and OOM: 2.3 (0.9), 3.4 (1.7), and 2.8 (2.1) min, respectively]. No adverse effects of sugammadex were detected throughout the study period. CONCLUSIONS: Sugammadex can be used to reverse profound rocuronium-induced block in ponies during isoflurane anaesthesia. Thoracic limb muscles represent a suitable alternative for monitoring neuromuscular block compared with pelvic limb muscles.

[Perioperative use of fluidwarmers reduces hypothermia in cats]. / Der Einsatz von Infusionswärmepumpen vermindert perioperative Hypothermie bei Katzen.

OBJECTIVE: Perioperative hypothermia is a common problem that must not be underestimated. There are plenty of methods to prevent or reduce heat loss during anaesthesia. The aim of this study was to evaluate the influence of warmed intravenous (IV) infusions to the perioperative decrease of body temperature of anaesthetized cats. MATERIAL AND METHODS: In this randomly designed study 30 cats undergoing surgical procedures were anaesthetized with a standardized anaesthesia protocol. Fifteen cats received IV infusions with room temperature; the IV infusion of the other 15 cats was constantly warmed to 38-39°C using a fluid warming device. The development of body temperature within the first 60 minutes of anaesthesia of both groups was compared and analysed. Additionally the influence of the room temperature on the body temperature and the influence of body temperature at the end of anaesthesia on the recovery period were evaluated. RESULTS: After 60 minutes of anaesthesia cats receiving warmed IV infusions had a significant higher body temperature than cats receiving IV infusions with room temperature. Room temperatures lower than 26°C had a significant influence on the development of perioperative hypothermia. The evaluation of the recovery period showed a significant correlation between low body temperature at the end of anaesthesia and prolonged time until extubation on the one hand and postoperative shivering on the other hand. CONCLUSION AND CLINICAL RELEVANCE: The present study shows that warmed IV infusions have a significant influence on the reduction of perioperative heat loss in cats. Nevertheless other additional methods to prevent heat loss are necessary to keep the patient in a normothermic range. Room temperatures play an essential role in decreasing hypothermia and should be at least 26°C. Low body temperature at the end of anaesthesia prolongs the recovery periode and enhances postoperative shivering.

Subcutaneous pre-anaesthetic medication with acepromazine-buprenorphine is effective as and less painful than the intramuscular route.

OBJECTIVES: To compare reaction to injection, sedation and propofol induction dose in dogs receiving acepromazine-buprenorphine pre-anaesthetic medication by the intramuscular or subcutaneous routes. METHODS: Fifty-two client owned dogs of American Society of Anesthesiologists grade I or II anaesthetised for diagnostic imaging. Dogs were randomly assigned to receive acepromazine 0.03 mg/kg and buprenorphine 0.02 mg/kg either intramuscular or subcutaneous. Reaction to injection was scored. Sedation was compared before and one hour after pre-anaesthetic medication. Propofol was administered in 1 mg/kg incremental injections until tracheal intubation was achieved. Total propofol dose was recorded. RESULTS: Reaction to injection was significantly greater (P=0.009) in the intramuscular group compared to the subcutaneous group. Sedation scores were not significantly different (P=0.523) between the intramuscular and the subcutaneous group. There was no statistically significant difference in propofol dose for induction (P=0.7). CLINICAL SIGNIFICANCE: Acepromazine-buprenorphine pre-anaesthetic medication provides a similar degree of sedation whether administered by the intramuscular or subcutaneous route. The intramuscular route is more painful compared to the subcutaneous route.

[Invasive arterial blood pressure measurement using an aneroid pressure system in cattle]. / Invasive arterielle Blutdruckmessung mittels eines aneroiden Systems beim Rind.

The aim of this study was to compare the results of invasive arterial blood pressure measurement using an electronic pressure transducer (EPT) or an aneroid pressure system (APS) in cattle. A catheter was placed in the auricular artery of 11 adult cattle and connected to a pressure transducer via pressure line. The aneroid system was connected to the same catheter using a three-way stop-cock in the pressure line. On five occasions three consecutive measurements were performed with the APS. The mean blood pressure values of the EPT were recorded before each individual measurement. Values from each device were compared using Passing and Bablok regression of agreement and a Bland and Altman difference plot. One hundred and forty-seven paired measurements were analysed. The average bias between the two methods (EPT vs. APS) was -1.6 mmHg (95 % confidence interval [CI]: -3.0 to -0.2 mmHg). The coefficient of correlation was 1.0084. The aneroid system showed an almost perfect agreement with the EPT. This study shows that it can be used in a clinical setting as well as under field conditions to measure arterial blood pressure in cattle.