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Objective To evaluate three routinely used tidal volumes (VT; 10, 12 and 15 mL kg−1) for controlled mechanical ventilation (CMV) in lung-healthy anaesthetized dogs by assessing alveolar ventilation (VTalv) and dead space (DS). Study design Prospective, randomized clinical trial. Animals A total of 36 client-owned dogs. Methods Dogs were randomly allocated to a VT of 10 (G10), 12 (G12) or 15 (G15) mL kg−1. After induction CMV was started. End-tidal carbon dioxide tension was maintained at 4.7–5.3 kPa by changing the respiratory frequency (fR; 6 anova and Student–Newman–Keuls tests with a statistical significance set at p Results No differences were observed for demographic data and cardiovascular variables between groups. A total of three dogs were excluded because of technical difficulties and one because of fR > 30. VTalv kg−1 (p = 0.001) increased and VDBohr (p = 0.002) decreased with greater VT. VTCO2,br (p = 0.017) increased and VDaw/VT (p = 0.006), VDBE (p = 0.008) and fR (p = 0.002) decreased between G10 and G15. PIP (p = 0.013) was significantly higher in G15 compared with that in G10 and G12. No changes were observed in MawP. Conclusions and clinical relevance A VT of 15 mL kg−1 is most appropriate for CMV in lung-healthy dogs (as evaluated by respiratory mechanics and VCap) and does not impair cardiovascular variables.

Objective To compare airway management during induction of anaesthesia, spontaneous ventilation (SV) and controlled mechanical ventilation (CMV), using an endotracheal tube (ETT), laryngeal mask (LM), rabbit-specific supraglottic airway device (v-gel) or facemask (FM). Study design Prospective randomized crossover experiment. Animals Ten New Zealand White rabbits. Methods After premedication, rabbits were randomly allocated to four groups: 1) ETT; 2) LM; 3) v-gel or 4) FM. The required dose of propofol, duration and number of attempts to place an airway device and leakage during SV and CMV at different peak inspiratory pressures (6, 10, 12, 14 and 16 cmH2O) were recorded. Computed tomography (CT) of the head, neck and abdomen were performed before and after CMV. Results Significantly less propofol and time [2.0 ± 0.5 mg kg−1, 82 ± 34 seconds, p 25% of the tidal volume occurred at the lowest pressure in FM [median (range), 6 (6–8) cmH2O], which was significantly lower than with v-gel [16 (6–no leak at 16) cmH2O], LM [>16 (6–no leak at 16)] or ETT [>16 (no leak at 16) cmH2O] (p Conclusions and clinical relevance The v-gel is a practical alternative to LM and ETT for airway management and CMV, but can compress the larynx. The FM is easily placed, but significant leakage occurs during CMV.

Objective Adenosine induces vasodilatation. The aim of this study was to investigate cardiovascular effects of two adenosine constant rate infusion (CRI) doses in dogs. Study design Experimental, longitudinal repeated measure design. Animals Ten healthy purpose-bred Beagle dogs. Methods Each dog was sedated with butorphanol. Anaesthesia was induced with propofol intravenously and maintained with sevoflurane (inspired oxygen fraction = 47–55%). Controlled mechanical ventilation was used to maintain normocapnia. Two doses of adenosine were administered as CRIs to each dog: 140 μg kg–1 minute–1 (A140) followed by 280 μg kg–1 minute–1 (A280). Pulse rate, invasive arterial pressure and stroke volume (by magnetic resonance phase contrast angiography) were measured at baseline, 3 minutes after starting adenosine and 3 and 10 minutes after discontinuing adenosine. Cardiac output, cardiac index and approximated systemic vascular resistances (approximate SVR) were calculated. Additionally, arterial blood gases, co-oximetry, electrolytes, glucose and lactate were measured and oxygen content and delivery calculated. One-way repeated measures analysis of variance (p Results A140 and A280 resulted in a significant decrease in arterial blood pressure [systolic (p = 0.008), mean (p = 0.003), and diastolic arterial pressure (p = 0.004)] and approximate SVR (p = 0.008) compared with baseline. No significant changes were detected for the other variables. All values returned to baseline within 3 minutes after adenosine discontinuation. Conclusions and clinical relevance Adenosine CRI decreases arterial pressure by vasodilatation in healthy dogs. No additional effects were observed with the higher dose. The effects in compromised dogs remain to be investigated.

The arterial to end-tidal CO2 difference (P(a-ET)CO2) and alveolar dead space fraction (VDalvfrac = P(a-ET)CO2/PaCO2), are used to estimate Enghoff's "pulmonary dead space" (V/QEng), a factor which is also influenced by venous admixture and other pulmonary perfusion abnormalities and thus is not just a measure of dead space as the name suggests. The aim of this experimental study was to evaluate which factors influence these CO2 indices in anesthetized spontaneously breathing horses. Six healthy adult horses were anesthetized in dorsal recumbency breathing spontaneously for 3 h. Data to calculate the CO2 indices (response variables) and dead space variables were measured every 30 min. Bohr's physiological and alveolar dead space variables, cardiac output (CO), mean pulmonary pressure (MPP), venous admixture [Formula: see text], airway dead space, tidal volume, oxygen consumption, and slope III of the volumetric capnogram were evaluated (explanatory variables). Univariate Pearson correlation was first explored for both CO2 indices before V/QEng and the explanatory variables with rho were reported. Multiple linear regression analysis was performed on P(a-ET)CO2 and VDalvfrac assessing which explanatory variables best explained the variance in each response. The simplest, best-fit model was selected based on the maximum adjusted R2 and smallest Mallow's p (Cp). The R2 of the selected model, representing how much of the variance in the response could be explained by the selected variables, was reported. The highest correlation was found with the alveolar part of V/QEng to alveolar tidal volume ratio for both, P(a-ET)CO2 (r = 0.899) and VDalvfrac (r = 0.938). Venous admixture and CO best explained P(a-ET)CO2 (R2 = 0.752; Cp = 4.372) and VDalvfrac (R2 = 0.711; Cp = 9.915). Adding MPP (P(a-ET)CO2) and airway dead space (VDalvfrac) to the models improved them only marginally. No "real" dead space variables from Bohr's equation contributed to the explanation of the variance of the two CO2 indices. P(a-ET)CO2 and VDalvfrac were closely associated with the alveolar part of V/QEng and as such, were also influenced by variables representing a dysfunctional pulmonary perfusion. Neither P(a-ET)CO2 nor VDalvfrac should be considered pulmonary dead space, but used as global indices of V/Q mismatching under the described conditions.

OBJECTIVE To compare the efficacy of three continuous positive airway pressure (CPAP) interfaces in dogs on gas exchange, lung volumes, amount of leak during CPAP and rebreathing in case of equipment failure or disconnection. STUDY DESIGN Randomized, prospective, crossover, experimental trial. ANIMALS Ten purpose-bred Beagle dogs. METHODS Dogs were in dorsal recumbency during medetomidine-propofol constant rate infusions, breathing room air. Three interfaces were tested in each dog in a consecutive random order: custom-made mask (M), conical face mask (FM) and helmet (H). End-expiratory lung impedance (EELI) measured by electrical impedance tomography was assessed with no interface (baseline), with the interface only (No-CPAP for 3 minutes) and at 15 minutes of 7 cmHO CPAP (CPAP-delivery). PaO was assessed at No-CPAP and CPAP-delivery, partial pressure of inspired carbon dioxide (PICO; rebreathing assessment) at No-CPAP and the interface leak (ΔP) at CPAP-delivery. Mixed-effects linear regression models were used for statistical analysis (p

Objective To evaluate the regional distribution of ventilation in horses during spontaneous breathing and controlled mechanical ventilation (CMV) using electrical impedance tomography (EIT). Study design Prospective, experimental case series. Animals Four anaesthetized experimental horses. Methods Horses were anaesthetized with isoflurane in an oxygen-air mixture and medetomidine continuous rate infusion, placed in dorsal recumbency with an EIT belt around the thorax, and allowed to breathe spontaneously until PaCO2 reached 13.3 kPa (100 mmHg), when volume CMV was started. For each horse, the EIT signal was recorded for at least 2 minutes immediately before (T1), and at 30 (n = 3) or 60 (n = 1) minutes after the start of CMV (T2). The centre of ventilation (CoV), dependent silent spaces (DSS) (likely to represent atelectatic lung areas), non-dependent silent spaces (NSS) (likely to represent lung areas with low ventilation) and total ventilated area (TVA) were evaluated. Cardiac output (CO) was measured and venous admixture and oxygen delivery (DO2) were calculated at T1 and T2. Data are presented as median and range. Results After the initiation of CMV, the CoV moved ventrally towards the non-dependent lung by 10% [from 57.4% (49.6–60.2%) to 48.3% (41.9–54.4%)]. DSS increased [from 4.1% (0.2–13.9%) to 18.7% (7.5–27.5%)], while NSS [21.7% (9.4–29.2%) to 9.9% (1.0–20.7%)] and TVA [920 (699–1051) to 837 (662–961) pixels] decreased. CO, venous admixture and DO2 also decreased. Conclusions and clinical relevance In spontaneously breathing anaesthetized horses in dorsal recumbency, ventilation was essentially centred within the dependent dorsal lung regions and moved towards non-dependent ventral regions as soon as CMV was started. This shows a major lack of ventilation in the dependent lung, which may be indicative of atelectasis.

History: Two cats were presented for orthopaedic surgery. Physical Examination: With the exception of the orthopaedic injuries found, clinical examination showed no abnormality. Management: As part of anaesthetic management, one cat received intrathecal morphine, the other epidural morphine. Following recovery, intense grooming was observed. After ensuring adequate analgesia this behaviour was interpreted as pruritus. In the first cat, pruritus was initially managed with medetomidine constant rate infusion (CRI) at 1 and 1.5 μg kg−1 hour−1. The lower dose produced sedation and no relief from pruritus, the higher dose ablated pruritus but induced sedation. Two propofol (lipid emulsion formulation) boli of 0.1 mg kg−1 ablated pruritus without causing sedation. The second cat was successfully treated with four boli of 0.1 mg kg−1 propofol over 20 minutes. Follow-up: Following treatment with propofol, pruritus did not recur in either cat and both were discharged from the hospital. Conclusions: This is the first clinical report of morphine-induced pruritus in cats and management with low-dose propofol. These cases suggest an antipruritic mechanism for lipid-formulation propofol.

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.

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

In a prospective cross-over study, the duration and magnitude of effect on the electrolyte and plasma volume changes of intravenous (IV) hypertonic hydroxyethyl starch (hyperHES) (7.5%/6%) and mannitol (20%) were compared. Eight Beagle dogs received an IV infusion of 4mL/kg hyperHES (group H) and 4mL/kg mannitol 20% (group M) on separate occasions. Urine and blood samples were taken in the first (T(60)) and second (T(120)) hour after infusion. Significant increases in plasma volume at each time point in group H and M were noted when compared to baseline (start of infusion=T(0)) level. There was no significant difference between groups. Both fluids resulted in diuresis, although no significant difference between groups was noted. A significant increase in plasma sodium (Na) was demonstrated in group H between T(0) and T(60) with a significant increase in the Na and chloride (Cl) fractional excretion (FE) between T(0), T(60) and T(120). In group M no changes in plasma electrolyte concentrations were detected, although FE of Na, Cl and K was increased significantly between T(0) and T(60). In conclusion, hyperHES and mannitol appear to have a volume expanding effect lasting at least 120 min. The hypernatraemia induced by hyperHES was minimal compared to previous reports of hypertonic saline use, and no clinical side effects were noted. HyperHES showed comparable effects to mannitol in increasing plasma volume and diuresis and could be considered for these applications.

Objective To compare physiologic dead space (VD) and physiologic dead space to tidal volume (VT) ratio (VD/VT) obtained by an automated single breath test for carbon dioxide (CO2) (method SBT) and a manual calculation (method MC) in ventilated healthy dogs. Study design Prospective clinical study. Animals Twenty client‐owned dogs, ASA I and II undergoing anaesthesia for clinical purposes. Methods Following pre‐medication, induction of anaesthesia, and intubation of the trachea, intermittent positive pressure ventilation was commenced. Mixed expired CO2 partial pressure (P ē CO2) was measured by two methods: method MC by analysis, using an infrared capnograph, of the expired gas collected in a mixing box and method SBT which calculated it automatically by a device consisting of a mainstream capnograph and a pneumotachograph. At four time points arterial partial pressure of CO2 (PaCO2) was measured. Physiologic dead space variables (VD and VD/VT) were calculated manually (method MC) or automatically (method SBT) using the Bohr–Enghoff equation. Method MC and SBT were compared using Bland–Altman plots and linear regression. Intra‐class correlation coefficient (ICC) was used to measure consistency of each method. Results Four measurement pairs were obtained in all 20 dogs for method SBT and MC. The bias was −1.15 mmHg, 7.97 mL and 0.02 for P ē CO2, VD and VD/VT, respectively. Linear regression analysis revealed a correlation coefficient (r2) of 0.79, 0.94, and 0.83 for P ē CO2, VD and VD/VT, respectively. The ICC revealed an excellent consistency for both methods. Conclusions The single breath test (SBT) can be used for clinical evaluation of VD and VD/VT in anaesthetized ventilated dogs. Clinical relevance Through measuring VD and VD/VT important information about lung ventilation can be obtained and the SBT is an easy method to use for this purpose.

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.

To compare the effects of propofol and alfaxalone on respiration in cats.Randomized, 'blinded', prospective clinical trial.Twenty cats undergoing ovariohysterectomy.After premedication with medetomidine 0.01 mg kg(-1) intramuscularly and meloxicam 0.3 mg kg(-1) subcutaneously, the cats were assigned randomly into two groups: group A (n = 10) were administered alfaxalone 5 mg kg(-1) minute(-1) followed by 10 mg kg(-1) hour(-1) intravenously (IV) and group P (n = 10) were administered propofol 6 mg kg(-1 ) minute(-1) followed by 12 mg kg(-1) hour(-1) IV for induction and maintenance of anaesthesia, respectively. After endotracheal intubation, the tube was connected to a non-rebreathing system delivering 100% oxygen. The anaesthetic maintenance drug rate was adjusted (± 0.5 mg kg(-1) hour(-1) ) every 5 minutes according to a scoring sheet based on physiologic variables and clinical signs. If apnoea 30 seconds, end-tidal carbon dioxide (Pe'CO2 ) 7.3 kPa (55 mmHg) or arterial haemoglobin oxygen saturation (SpO2 ) 90% occurred, manual ventilation was provided. Methadone was administered postoperatively. Data were analyzed using independent-samples t-tests, Fisher's exact test, linear mixed-effects models and binomial test.Manual ventilation was required in two and eight of the cats in group A and P, respectively (p = 0.02). Two cats in both groups showed apnoea. Pe'CO2 7.3 kPa was recorded in zero versus four and SpO2 90% in zero versus six cats in groups A and P respectively. Induction and maintenance dose rates (mean ± SD) were 11.6 ± 0.3 mg kg(-1) and 10.7 ± 0.8 mg kg(-1) hour(-1) for alfaxalone and 11.7 ± 2.7 mg kg(-1) and 12.4 ± 0.5 mg kg(-1) hour(-1) for propofol.Alfaxalone had less adverse influence on respiration than propofol in cats premedicated with medetomidine. Alfaxalone might be better than propofol for induction and maintenance of anaesthesia when artificial ventilation cannot be provided.

BACKGROUND: In critically ill patients with significant pulmonary hypertension (PH), close perioperative cardiovascular monitoring is mandatory, considering the increased morbidity and mortality in this patient group. Although the pulmonary artery catheter is still the standard for the diagnosis of PH, its use to monitor cardiac output (CO) in patients with PH is decreasing as a result of increased morbidity and possible influence of tricuspid regurgitation on the measurements. However, continuous CO measurement methods have never been evaluated under PH regarding their agreement and trending ability. In this study, we evaluated the influence of acute PH and different CO states on transpulmonary thermodilution (TPTD) and calibrated pulse contour analysis (PiCCO; both assessed with PiCCO plus(TM)), intermittent pulmonary artery thermodilution (PATD), and continuous thermodilution (CCO) compared with a modified Fick method (FICK) in an animal model. METHODS: Nine healthy pigs were studied under anesthesia. PH of 25 and 40 mm Hg (by administration of the thromboxane analog U46619), CO decreases, and CO increases were induced to test the different CO measurement techniques over a broad range of hemodynamic situations. Before each step, a new baseline data set was collected. CO values were compared using Bland-Altman analysis; trending abilities were assessed via concordance and polar plot analysis. The influence of pulmonary pressure on CO measurements was analyzed using linear mixed models. RESULTS: A mean bias of -0.26 L/min with prediction intervals of -0.88 to 1.4 L/min was measured between TPTD and FICK. Their concordance rate was 100% (94%-100% confidence interval), and the mean polar angle -3[degrees] with radial limits of agreement of +/-28[degrees] indicated good trending abilities. PATD compared with FICK also showed good trending ability. Comparisons of PiCCO and CCO versus FICK revealed low agreement and poor trending results with concordance rates of 84% (71%-93%) and 88% (74%-95%), mean polar angles from -17[degrees] and -19[degrees], and radial limits of agreement of +/-45[degrees] and 40[degrees]. Pulmonary pressures influenced only the difference between FICK and PiCCO, as assessed by linear mixed models. CONCLUSIONS: TPTD compared with FICK was able to track all changes induced during the study period, including those by PH. It yielded better agreement than PATD both compared with FICK. PiCCO and CCO were not mapping all changes correctly, and when used clinically in unstable patients, regular controls with intermittent techniques are required. Acute pharmacologically induced PH did influence the difference between FICK and PiCCO.

Objective To review the evidence regarding the reversal of neuromuscular block (NMB) in companion animals with emphasis on the development and use of newer agents. Database used Data sources include scientific reviews and original research publications in both human and veterinary literature using Pubmed and Scopus as search data bases. Unpublished and locally published data on reversal of NMB are presented. Conclusions Residual NMB has been shown to increase morbidity and mortality in humans and needs to be avoided. It can be detected only by adequate neuromuscular monitoring. The proper use of reversal agents avoids residual NMB and recurarization should not occur. Anticholinesterase inhibitors, such as edrophonium and neostigmine have been used to reverse NMB when the need for this has been established. Reversal is influenced by several factors and a number of undesirable side- effects of these drugs have been reported. Sugammadex, a γ-cyclodextrin, which was designed specifically to encapsulate rocuronium, is more rapid in its actions, has fewer side effects and can reverse profound NMB induced by aminosteroidal muscle relaxants.

The aim of this study was to test the effect of cardiac output (CO) and pulmonary artery hypertension (PHT) on volumetric capnography (VCap) derived-variables. Nine pigs were mechanically ventilated using fixed ventilatory settings. Two steps of PHT were induced by IV infusion of a thromboxane analogue: PHT25 [mean pulmonary arterial pressure (MPAP) of 25 mmHg] and PHT40 (MPAP of 40 mmHg). CO was increased by 50 % from baseline (COup) with an infusion of dobutamine ≥5 μg kg(-1) min(-1) and decreased by 40 % from baseline (COdown) infusing sodium nitroglycerine ≥30 μg kg(-1) min(-1) plus esmolol 500 μg kg(-1) min(-1). Another state of PHT and COdown was induced by severe hypoxemia (FiO2 0.07). Invasive hemodynamic data and VCap were recorded and compared before and after each step using a mixed random effects model. Compared to baseline, the normalized slope of phase III (SnIII) increased by 32 % in PHT25 and by 22 % in PHT40. SnIII decreased non-significantly by 4 % with COdown. A combination of PHT and COdown associated with severe hypoxemia increased SnIII by 28 % compared to baseline. The elimination of CO2 per breath decreased by 7 % in PHT40 and by 12 % in COdown but increased only slightly with COup. Dead space variables did not change significantly along the protocol. At constant ventilation and body metabolism, pulmonary artery hypertension and decreases in CO had the biggest effects on the SnIII of the volumetric capnogram and on the elimination of CO2.

Dieser Artikel beschreibt die adaquate Anwendung von Kristalloiden und Kolloiden beim Kleintier. Dabei werden praktische Uberlegungen fur die Wahl der korrekten Infusionslosung, die Verabreichungsart und die Infusionsrate diskutiert.

Objective The aim of this study was to investigate normal values for the dynamic compliance of the respiratory system (Crs) and respiratory system resistance (Rrs) in mechanically ventilated anaesthetized dogs. Study design Prospective clinical study. Animals Forty healthy dogs undergoing elective orthopaedic surgery. Body weight was (mean ± SD) 26.8 ± 10.7 kg (range: 1.9–45.0 kg), age 4.7 ± 2.9 years (range: 0.1–10.6 years). Methods Dogs were premedicated with acepromazine and methadone administered intramuscularly and anaesthesia induced with propofol intravenously. After endotracheal intubation the dog's lungs were connected to an appropriate breathing system depending on body weight and isoflurane in oxygen administered for maintenance of anaesthesia. The lungs were ventilated mechanically with variables set to maintain normocapnia (end‐tidal carbon dioxide concentration 4.7–6.0 kPa). Peak inspiratory pressure, Crs, Rrs, tidal volume, respiratory rate and positive end‐expiratory pressure were recorded at 5, 30, 60, 90 and 120 minutes after start of mechanical ventilation. Cardiovascular variables were recorded at time of collection of respiratory data. Results General additive modeling revealed the following relationships: Crs = [0.895 × body weight (kg)] + 8.845 and Rrs = [−0.0966 × body weight (kg)] + 6.965. Body weight and endotracheal tube diameter were associated with Crs ( p 0.001 and p = 0.002 respectively) and Rrs ( p = 0.017 and p = 0.002 respectively), body weight being linearly related to Crs and inversely to Rrs. Conclusion and clinical relevance Body weight was linearly related to Crs while Rrs has an inverse linear relationship with body weight in mechanically ventilated dogs. The derived values of Crs and Rrs may be used for monitoring of lung function and ventilation in healthy dogs under anaesthesia.

Objective To compare acid–base balance and incidence of hyperchloraemic metabolic acidosis following administration of three crystalloid solutions to dogs undergoing anaesthesia for orthopaedic surgery. Study design Prospective, randomised, clinical study. Animals Sixty dogs. Methods During a non–standardised anaesthetic, 0.9% saline (S), Hartmann's solution (H) or a polyionic glucose–free maintenance solution (M) was administered IV at 10 mL kg−1 hour−1. Venous blood pH, PCO2, PCV, total protein, urea, sodium, potassium and chloride concentrations were measured at induction of anaesthesia (T0) and after 2 hours of fluid therapy (T2). Base excess (BE), bicarbonate, corrected chloride concentration (corrCl), osmolality, change in plasma volume (PV) and strong ion gap (SIG) were calculated. Changes in variables within groups (1–sample Student's t–test/Wilcoxon signed rank test) and between groups (1–way anova /Kruskal–Wallis) were assessed. Data are presented as median (interquartile range). Significance was set at p Results No significant differences existed between groups for pH, PCO2, PCV, total protein, urea, potassium, corrCl, PV and SIG. Potassium significantly increased in all groups. Significant differences existed between groups S and M for BE, sodium, chloride, bicarbonate and osmolality, and between groups H and M for sodium and osmolality. Chloride concentration significantly changed from 116 (114–117) to 117 (116–119) mmol L−1 in group S, 116 (115–118) to 115 (113–117) mmol L−1 in group H and 116 (115–118) to 114 (113–118) mmol L−1 in group M. In groups H and M, sodium and osmolality decreased, and BE and bicarbonate concentration increased significantly. Plasma volume increased by 28 (14–44)%, 25 (5–40)% and 24 (13–33)% in groups S, H and M, respectively. Conclusion and clinical relevance Hyperchloraemic metabolic acidosis did not develop after intraoperative 0.9% saline, Hartmann's solution or maintenance solution at 10 mL kg−1 hour−1 for 2 hours in dogs undergoing elective orthopaedic surgery. Bicarbonate and BE increased after Hartmann's and maintenance solutions. Increases in potassium concentration were unexplained.

Objective To investigate whether the method used to attach matrix-type fentanyl patches influences the degree of skin attachment and the amount of active drug remaining in patches after use. Study design Prospective, randomised clinical study. Study population Fifteen adult dogs of mixed breeds. Methods Two equally sized matrix-type fentanyl patches were attached to the dorsal third of the lateral thorax of fifteen dogs for 72 hours. The two patches were attached using different techniques: Method AD used an adhesive dressing in combination with a transparent film. Method TG used tissue adhesive applied to the edges of the patch. After 72 hours the patches were removed and the proportion of the patch attached at this time calculated. The residual content of the patches was analysed using a validated gas chromatography–mass spectrometery (GC–MS) analysis technique. Results After 72 hours of continuous attachment, the mean proportion of drug uptake for method AD was 17.2 (SD ± 11.1)% and for method TG this was 16.9 (SD ± 7.3)%. The median proportion of attachment for method AD was 100% and for method TG was 95.6%. Conclusions The method of attachment did not significantly influence the uptake of fentanyl from matrix-type patches. The method of attachment resulted in a significant difference in the proportion of the patch attached 72 hours after placement, with method AD resulting in a greater median proportion of attachment than TG. Clinical relevance The method used to attach matrix-type fentanyl patches to dogs should not interfere with drug uptake. The residual fentanyl content remaining in these patches after 72 hours of continuous application is significant and could lead to intoxication if ingested by humans.

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.

Sixteen captive female red deer were successfully anesthetized to surgically implant a telemetry system. The deer were immobilized with (mean±SD) 1.79±0.29 mg/kg xylazine and 1.79±0.29 mg/kg tiletamine/zolazepam given intramuscularly with a dart gun. Anesthesia was maintained for 69±2 min using a total intravenous protocol with a catheter placed in the jugular vein. Group X received xylazine (0.5±0.055 mg/kg/hr) and group D, detomidine (2±0.22 μg/kg/hr), both in combination with ketamine (2±0.02 mg/kg/hr) and midazolam (0.03±0.0033 mg/kg/hr), as a constant rate infusion. Anesthesia was reversed with 0.09±0.01 mg/kg atipamezole and 8.7±1.21 μg/kg sarmazenil given intravenously in both groups. These drug combinations provided smooth induction, stable anesthesia for surgery, and rapid recovery. Respiratory depression and mild hypoxemia were seen, and we, therefore, recommend using supplemental intranasal oxygen.

The purpose of this study was to evaluate if pre-anaesthetic thoracic radiographs contribute to the anaesthetic management of trauma patients by comparing American Society of Anesthesiologists Physical Status Classification (ASA grade) with and without information from thoracic radiography findings. Case records of 157 dogs and cats being anaesthetized with or without post-traumatic, pre-anaesthetic chest radiographs were retrospectively evaluated for clinical parameters, radiographic abnormalities and anaesthetic protocol. Animals were retrospectively assigned an ASA grade. ASA grades, clinical signs of respiratory abnormalities and anaesthesia protocols were compared between animals with and without chest radiographs. The group of animals without pre-anaesthetic radiographs was anaesthetized earlier after trauma and showed less respiratory abnormalities at presentation. The retrospectively evaluated ASA grade significantly increased with the information from thoracic radiography. Animals with a higher ASA grade were less frequently mechanically ventilated. Pre-anaesthetic radiographs may provide important information to assess the ASA grade in traumatized patients and may therefore influence the anesthesia protocol.

Zusammenfassung Gegenstand und Ziel: Beschreibung einer Katze mit Atem- und Kreislaufstillstand verursacht durch Hyperkaliämie nach ischämischer Muskelnekrose. Pathogenese, Klinik, Komplikationen und Therapie von ischämischer Muskelnekrose werden diskutiert und mögliche Ursachen, Symptome und Therapiemöglichkeiten einer Hyperkaliämie beschrieben. Material und Methoden: Fallbericht einer vierjährigen, männlich-kastrierten Hauskatze. Ergebnisse: Die Katze wurde erfolgreich reanimiert und die Hyperkaliämie ließ sich mittels verschiedener Therapieansätze normalisieren. Der Kater konnte nach Hause entlassen werden. Schlussfolgerungen: Bei ischämischer Muskelnekrose kann es während der Reperfusionsphase zu einer lebensgefährlichen Hyperkaliämie kommen, die überwacht und entsprechend therapiert werden muss. Bei aggressiver Flüssigkeitstherapie ist das Risiko einer Kaliumund Toxinfreisetzung aus dem ischämischen Muskel unter Umständen größer. Klinische Relevanz: Bei ischämischer Muskelnekrose sollten Kaliumkonzentration und Säure-Basen-Haushalt regelmäßig überwacht werden.