Veterinary and Comparative Orthopaedics and Traumatology, 2006
SummaryThis paper reports the surgical treatment of a tibial fracture in a castrated adult male B... more SummaryThis paper reports the surgical treatment of a tibial fracture in a castrated adult male Belgian Landrace pig of 180 kg. The fracture was repaired using an intramedullary Steinmann pin, combined with cerclage wire and external transfixation. In contrast to other animal species, the fracture repair in the pig was hindered by the short and curved bones, the thick subcutaneous fat layer and the pronounced musculature. Postoperatively, the pig developed an osteomyelitis of the tibia due to pin tract contamination. Despite this complication, the fracture healed acceptably when all fixation material was removed two months after surgery. The infection resolved quickly and a satisfactory clinical result was obtained.
Objective To investigate the anatomy of the ear innervation in horses and develop a new approach ... more Objective To investigate the anatomy of the ear innervation in horses and develop a new approach for the block of the internal and external pinna and acoustic meatus. Study design Prospective, descriptive, cadaveric study. Animals Twenty-five heads and necks from horse cadavers. Methods Phase I: anatomical dissection and dye deposition on 19 heads. With the head positioned in lateral recumbency, 10 mL methylene blue (1:1 sterile water) for the internal auricular and 2 mL for the great auricular nerve block were injected in 21 ears (7 left, 10 right and 2 bilaterally). The anatomy of all the ears (bilaterally) and the accuracy of dye deposition (successful nerve staining defined as < 2 cm) was assessed following dissection. Occurrence of intra-parotid, intra-vascular or intra-neural injection was recorded. Phase II: the same technique and volumes were applied, bilaterally, using a lidocaine 2%:iohexol solution mixture (3:1) in 6 different cadavers. Computed tomography (CT) was performed and the needle position and spread of the mixture evaluated and recorded. Results Phase I: Inter-and intra-individual differences were found in the anatomy of the great auricular nerve, but not in the internal and lateral auricular nerve branches and the caudal auricular nerve. No auriculotemporal nerve was found. Nerve staining was successful in 95% of the cases for the great auricular nerve, 85% of the cases for the internal auricular nerve, and 100% of the cases for the lateral auricular branch and caudal auricular nerve. Failure was observed in horses with abundant peri-auricular fat. No intra-vascular, intra-parotid or intraneural injections occurred. Phase II: A 100% success rate was recorded from CT images.
Veterinary anaesthesia and analgesia, Jan 21, 2014
To investigate the influence of two inspired oxygen fractions (Fi'O2 ) on the arterial oxygen... more To investigate the influence of two inspired oxygen fractions (Fi'O2 ) on the arterial oxygenation in horses anaesthetized with isoflurane. Retrospective, case-control clinical study. Two hundred equine patients undergoing non-abdominal surgery (ASA class 1-2), using a standardized anaesthetic protocol and selected from anaesthetic records of a period of three years, based on pre-defined inclusion criteria. In group O (n = 100), medical oxygen acted as carrier gas, while in group M (n = 100), a medical mixture of oxygen and air (Fi'O2 0.60) was used. Demographic data, Fi'O2 , arterial oxygen tension (PaO2 ) and routinely monitored physiologic data were recorded. The alveolar-arterial oxygen tension difference [P(A-a)O2 ] and PaO2 /Fi'O2 ratio were calculated. The area under the curve, standardized to the anaesthetic duration, was calculated and statistically compared between groups using t-tests or Mann-Whitney tests as appropriate. Categorical data were compared usi...
precision and accuracy were evaluated and the results fell within the ranges specified. The limit... more precision and accuracy were evaluated and the results fell within the ranges specified. The limit of quantification was 0.1 µg/mL for both analytes, whereas limits of detection were 9.6 and 3.5 ng/mL for ketamine and norketamine, respectively. The method was applied on biological samples from a pharmacokinetic study in calves and demonstrated the suitability of the method for this application.
In Belgium and even in northern Europe Rhinosporidium seeberi has not been reported in autochtono... more In Belgium and even in northern Europe Rhinosporidium seeberi has not been reported in autochtonous people or animals. In this paper, the authors report the first observation of laryngeal masses, caused by Rhinosporidium seeberi, in a Belgian Warmblood horse. Moreover, laryngeal rhinosporidiosis is extremely rare since this localisation is only described in four human cases.
Veterinary Clinics of North America: Equine Practice, 2013
Despite the use of balanced anesthesia and fluids, drugs for cardiovascular support are often nee... more Despite the use of balanced anesthesia and fluids, drugs for cardiovascular support are often needed in anesthetized horses. Antimuscarinics can be used to treat bradycardia unrelated to hypertension. Vasopressors can be useful when hypotension is caused by vasodilation and/or when the effect of fluids and inotropes is insufficient. In most cases, however, inotropes, including sympathomimetics, calcium salts, and phosphodiesterase inhibitors, are preferred. Of the β-sympathomimetics, dobutamine remains the agent of choice. Calcium salts are mainly useful in hypocalcemic patients. Phosphodiesterase inhibitors may offer an alternative solution, but more research is needed.
Objective Enoximone is a phosphodiesterase III inhibitor frequently used to improve cardiac outpu... more Objective Enoximone is a phosphodiesterase III inhibitor frequently used to improve cardiac output (CO) in man. As the use of enoximone has not been reported in horses, the effects of this inodilator were examined in isoflurane anaesthetized ponies. Study design Prospective, randomised, experimental study. Conclusions and clinical relevance The present results suggest that in isoflurane anaesthetized ponies, enoximone has beneficial effects on CO and SV without producing significant changes in blood pressure. Despite an increase in _ Qs/ _ Qt, _ DO 2 to the tissues was improved.
Objective To evaluate the combined effects of enoximone and dobutamine on the cardiovascular syst... more Objective To evaluate the combined effects of enoximone and dobutamine on the cardiovascular system and respiratory gas exchange in isofluraneanaesthetized ponies. Study design Prospective, randomized, experimental study. Animals Six ponies (286 ± 52 kg), aged 5.0 ± 1.6 years. Methods After sedation (romifidine 80 lg kg)1), anaesthesia was induced with midazolam (0.06 mg kg)1) and ketamine (2.2 mg kg)1) and maintained with isoflurane in oxygen. The ponies were ventilated to maintain eucapnia. After 90 minutes (=T0), enoximone alone (0.5 mg kg)1) (E) or enoximone, followed by a constant rate infusion of dobutamine (0.5 lg kg)1 minute)1) (ED) for 120 minutes, was administered. Each pony received both treatments in a crossover trial, with at least 2 weeks between treatments. Heart rate (HR), cardiac output (CO), stroke volume (SV), right atrial (RAP), systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP), blood gases, systemic vascular resistance (SVR), oxygen delivery (_ DO 2) and several respiratory gas exchange variables were measured before treatment and until T120. Statistical analysis was based on a mixed model with treatment, time and their interaction as fixed categorical effects, pony as random effect, comparing treatments globally (a = 0.05) and at specific timepoints (Bonferroni-adjusted a = 0.00625). Results Compared to enoximone alone, ED treatment produced an increase in HR, CO, SV, RAP, SAP, DAP, MAP, packed cell volume (PCV) and _ DO 2. The difference was significant from T60 to T120 (except at T80) for HR, throughout the observational period for CO, SAP, MAP, PCV and _ DO 2 , from T40 to T120 for DAP, at T10,T60,T80 and T120 for SV and at T10 and T20 for RAP. Overall decreases occurred in SVR and dead space ventilation (V D /V T). V D /V T was lower at T20 and from T80 to T120. Venous oxygen saturation was increased from T60 onwards. Conclusions and clinical relevance The results suggest that enoximone and dobutamine have additive cardiovascular effects and reduce V D /V T in isoflurane-anaesthetized ponies.
Objective To evaluate the cardiopulmonary effects of two different constant rate infusions (CRI) ... more Objective To evaluate the cardiopulmonary effects of two different constant rate infusions (CRI) of dexmedetomidine (1 and 1.75 lg kg)1 hour)1) in experimental ponies. Animals Six healthy ponies (mean 306 ± SD 71 kg, 7.0 ± 1.6 years). Study design Prospective, randomized, experimental study. Methods After premedication with intravenous (IV) dexmedetomidine (3.5 lg kg)1), anaesthesia was induced (T0) with ketamine (2.2 mg kg)1 IV) and midazolam (0.06 mg kg)1 IV) and maintained with isoflurane (FE¢ISO 1.50%) in 55% oxygen for 150 minutes. Normocapnia was maintained using artificial ventilation. Three ponies received dexmedetomidine CRIs of 1 and 1.75 lg kg)1 hour)1 from T30 to T60 and T90 to T120 respectively. In the other three ponies, the order of the doses was reversed. Continuous monitoring included pulse oximetry, electrocardiography, anaesthetic gas monitoring, arterial and central venous pressures. Cardiac ouput (LiDCO technique) was measured and arterial and venous bloods taken every 15 minutes. Cardiac index (CI), systemic vascular resistance (SVR), arterial and venous oxygen content (CaO 2 , CvO 2) and oxygen delivery (_ DO 2) were calculated. Analysis of variance with separate models for each CRI rate was used to detect differences between values obtained at the end of the CRI and their respective baseline values. A mixed model with these differences as response variable, pony as random effect and treatment and period as fixed effects was applied to find differences between the two CRIs (a = 0.05 for all analyses). Results Heart rate (HR), CI, CaO 2 , CvO 2 and _ DO 2 decreased significantly, while significant increases were found in SVR, systolic arterial pressure and right atrial pressure with both infusion rates. No differences were found between the two dexmedetomidine CRI rates. Conclusions and clinical relevance Although significant, cardiopulmonary effects of the dexmedetomidine CRIs in isoflurane anaesthetized ponies were small, without differences between the two dose rates.
To compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those... more To compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those of morphine alone on the minimum end-tidal sevoflurane concentration necessary to prevent movement (MACNM ) in ponies. Prospective, randomized, crossover, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;blinded&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;, experimental study. Five healthy adult gelding ponies were anaesthetized twice with a 3-week washout period. After induction of anaesthesia with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (Fe&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;SEVO 2.5%) in 55% oxygen. Monitoring included pulse oximetry, electrocardiography and measurement of anaesthetic gases, arterial blood pressure and body temperature. The ponies were mechanically ventilated and randomly allocated to receive IV treatment M [morphine 0.15 mg kg⁻¹ (T10-T15) followed by a CRI (0.1 mg kg⁻¹ hour⁻¹)] or treatment DM [dexmedetomidine 3.5 μg kg⁻¹ plus morphine 0.15 mg kg⁻¹ (T10-T15) followed by a CRI of dexmedetomidine 1.75 μg kg⁻¹ hour⁻¹ and morphine 0.1 mg kg⁻¹ hour⁻¹]. At T60, a stepwise MACNM determination was initiated using constant current electrical stimuli at the skin of the lateral pastern region. Triplicate MACNM estimations were obtained and then averaged in each pony. Wilcoxon signed-rank test was used to detect differences in MAC between treatments (α = 0.05). Sevoflurane-morphine MACNM values (median (range) and mean ± SD) were 2.56 (2.01-4.07) and 2.79 ± 0.73%. The addition of a continuous infusion of dexmedetomidine significantly reduced sevoflurane MACNM values to 0.89 (0.62-1.05) and 0.89 ± 0.22% (mean MACNM reduction 67 ± 11%). Co-administration of dexmedetomidine and morphine CRIs significantly reduced the MACNM of sevoflurane compared with a CRI of morphine alone at the reported doses.
Objective To investigate the cardiovascular effects of epidural romifidine in isoflurane-anaesthe... more Objective To investigate the cardiovascular effects of epidural romifidine in isoflurane-anaesthetized dogs. Study design Prospective, randomized, blinded experiment. Animals A total of six healthy adult female Beagles aged 1.25 ± 0.08 years and weighing 12.46 ± 1.48 (10.25-14.50) kg.
Objective To evaluate the effects of a constant rate infusion (CRI) of romifidine on the requirem... more Objective To evaluate the effects of a constant rate infusion (CRI) of romifidine on the requirement of isoflurane, cardiovascular performance and recovery in anaesthetized horses undergoing arthroscopic surgery. Study design Randomized blinded prospective clinical trial. Animals Thirty horses scheduled for routine arthroscopy. Methods After premedication (acepromazine 0.02 mg kg)1 , romifidine 80 lg kg)1 , methadone 0.1 mg kg)1) and induction (midazolam 0.06 mg kg)1 ketamine 2.2 mg kg)1), anaesthesia was maintained with isoflurane in oxygen. Horses were assigned randomly to receive a CRI of saline (group S) or 40 lg kg)1 hour)1 romifidine (group R). The influences of time and treatment on anaesthetic and cardiovascular parameters were evaluated using an analysis of variance. Body weight (t-test), duration of anaesthesia (t-test) and recovery score (Wilcoxon Rank Sum Test) were compared between groups. Significance was set at p < 0.05. Results All but one horse were positioned in the dorsal recumbent position and ventilated from the start of anaesthesia. End tidal isoflurane concentrations were similar in both groups at similar time points and over the whole anaesthetic period. Cardiac output was significantly lower in horses of the R group, but there were no significant differences between groups in cardiac index, body weight or age. All other cardiovascular parameters were similar in both groups. Quality of recovery did not differ significantly between groups, but more horses in group R stood without ataxia at the first attempt. One horse from group S had a problematic recovery. Conclusions and clinical relevance No inhalation anaesthetic sparing effect or side effects were observed by using a 40 lg kg)1 hour)1 romifidine CRI in isoflurane anaesthetized horses under clinical conditions. Cardiovascular performance remained acceptable. Further studies are needed to identify the effective dose of romifidine that will induce an inhalation anaesthetic sparing effect in anaesthetized horses.
Objective To investigate the influence of a dexmedetomidine constant rate infusion (CRI) in horse... more Objective To investigate the influence of a dexmedetomidine constant rate infusion (CRI) in horses anaesthetized with isoflurane. Study design Prospective, randomized, blinded, clinical study. Animals Forty adult healthy horses (weight mean 491 ± SD 102 kg) undergoing elective surgery. Methods After sedation [dexmedetomidine, 3.5 lg kg)1 intravenously (IV)] and induction IV (midazolam 0.06 mg kg)1 , ketamine 2.2 mg kg)1), anaesthesia was maintained with isoflurane in oxygen/air (FiO 2 55-60%). Horses were ventilated and dobutamine was administered when hypoventilation [arterial partial pressure of CO 2 > 8.00 kPa (60 mmHg)] and hypotension [arterial pressure 70 mmHg] occurred respectively. During anaesthesia, horses were randomly allocated to receive a CRI of dexmedetomidine (1.75 lg kg)1 hour)1) (D) or saline (S). Monitoring included end-tidal isoflurane concentration, cardiopulmonary parameters, and need for dobutamine and additional ketamine. All horses received 0.875 lg kg)1 dexmedetomidine IV for the recovery period. Age and weight of the horses, duration of anaesthesia, additional ketamine and dobutamine, cardiopulmonary data (ANOVA), recovery scores (Wilcoxon Rank Sum Test), duration of recovery (t-test) and attempts to stand (Mann-Whitney test) were compared between groups. Significance was set at p < 0.05. Results Heart rate and arterial partial pressure of oxygen were significantly lower in group D compared to group S. An interaction between treatment and time was present for cardiac index, oxygen delivery index and systemic vascular resistance. Endtidal isoflurane concentration and heart rate significantly increased over time. Packed cell volume, systolic, diastolic and mean arterial pressure, arterial oxygen content, stroke volume index and systemic vascular resistance significantly decreased over time. Recovery scores were significantly better in group D, with fewer attempts to stand and significantly longer times to sternal position and first attempt to stand. Conclusions and clinical relevance A dexmedetomidine CRI produced limited cardiopulmonary effects, but significantly improved recovery quality.
Objective To evaluate the cardiovascular effects of a preload of hydroxyethylstarch 6% (HES), pre... more Objective To evaluate the cardiovascular effects of a preload of hydroxyethylstarch 6% (HES), preceding an epidural administration of ropivacaine 0.75% in isoflurane anaesthetized dogs. Animals Six female, neutered Beagle dogs (mean 13.3 ± SD 1.0 kg; 3.6 ± 0.1 years). Study design Randomized experimental cross-over study (washout of 1 month).
Objective To examine the influence of a detomidine constant rate infusion (CRI) on cardiovascular... more Objective To examine the influence of a detomidine constant rate infusion (CRI) on cardiovascular function, isoflurane requirements and recovery quality in horses undergoing elective surgery. Study design Prospective, randomized, blinded, clinical trial. Animals Twenty adult healthy horses. Methods After sedation (detomidine, 10 lg kg)1 intravenously [IV]) and induction of anaesthesia (midazolam 0.06 mg kg)1 , ketamine 2.2 mg kg)1 IV), anaesthesia was maintained with isoflurane in oxygen/air (inspiratory oxygen fraction 55%). When indicated, the lungs were mechanically ventilated. Dobutamine was administered when MAP < 70 mmHg. The horses were randomly allocated to one of two groups and throughout anaesthesia, received either a detomidine (5 lg kg)1 hour)1) (D) or saline (S) CRI, with the anaesthetist unaware of the treatment. Monitoring included end-tidal isoflurane concentration, arterial pH, PaCO 2 , PaO 2 , dobutamine administration rate, heart rate (HR), arterial pressure, cardiac index (CI), systemic vascular resistance (SVR), stroke index and oxygen delivery index (_ DO 2 I). For recovery from anaesthesia, all horses received 2.5 lg kg)1 detomidine IV. Recovery quality and duration were recorded in each horse. For statistical analysis, ANOVA, Pearson chi-square and Wilcoxon rank sum tests were used as relevant. Results Heart rate (p = 0.0176) and _ DO 2 I (p = 0.0084) were lower and SVR higher (p = 0.0126) in group D, compared to group S. Heart rate (p = 0.0011) and pH (p = 0.0187) increased over time. Significant differences in isoflurane requirements were not detected. Recovery quality and duration were comparable between treatments. Conclusions and clinical relevance A detomidine CRI produced cardiovascular effects typical for a 2agonists, without affecting isoflurane requirements, recovery duration or recovery quality.
Objective To evaluate the cardiopulmonary effects of sufentanil long acting (SLA) in sevofluranea... more Objective To evaluate the cardiopulmonary effects of sufentanil long acting (SLA) in sevofluraneanaesthetized dogs. Study Design Randomized prospective study. Animals Forty female dogs (beagles) aged 1-2 years, weighing 11.97 ± 1.40 kg. Materials and methods The dogs were divided into five groups of eight. Two control groups were used: group A received intramuscular (IM), SLA (50 lg kg)1) alone, while group B received the SLA vehicle followed by sevoflurane anaesthesia for 90 minutes. In the other groups, SLA (50 lg kg)1 IM) was given immediately before (group C 0), 15 minutes before (group D 15) or 30 minutes (group E 30) before induction [with intravenous (IV) thiopental] of sevoflurane anaesthesia lasting for 90 minutes. Heart rate, arterial blood pressure, respiratory rate (f r), arterial oxygen haemoglobin saturation and end-tidal sevoflurane concentration (FE¢SEVO) were measured every 10 minutes during anaesthesia and at 2, 4 and 24 hours after induction (not FE¢SEVO). Acid-base and blood gas analyses were performed. Results Sufentanil LA reduced heart rate and increased arterial CO 2 tensions during anaesthesia. Respiratory depression was least in group E 30 compared with groups C 0 and D 15. Bradycardia was present for at least 24 hours. Respiratory rate was least in group B although arterial O 2 and CO 2 tension values were acceptable up to 24 hours after anaesthesia. Conclusions Pre-anaesthetic medication with SLA moderately aggravated the cardiopulmonary effects of sevoflurane. Clinical relevance In spite of a moderate depressant effect on cardiorespiratory parameters, SLA may be of use as pre-anaesthetic medication before sevoflurane anaesthesia in dogs. Intermittent positive pressure ventilation may occasionally be necessary.
The purpose of the present study was to determine the most effective time interval between the ad... more The purpose of the present study was to determine the most effective time interval between the administration of sufentanil long acting (LA) and the induction of sevoflurane anaesthesia in dogs. The occurrence of sedation, analgesia and other marked side-effects were evaluated in addition to the possible dosage-reducing effect of sufentanil on sevoflurane in dogs. Forty clinically normal beagles aged 1-2 years and weighing between 8.4 and 13.6 kg were included. Two control groups were used: one group of dogs (A) received sufentanil LA (50 lg/kg i.m.) and a second group (B) the sufentanil vehicle followed by standard inhalation anaesthesia of 90 min. After premedication with sufentanil LA immediately before (C 0), 15 min (D 15) or 30 min (E 30) prior to induction with thiopental (i.v.) the dogs were anaesthetized for 90 min with sevoflurane in oxygen. Pain and sedation scores were evaluated every 10 min during sevoflurane anaesthesia and at 2 (T 120), 4 (T 240) and 24 h (T 1440) after initiation of anaesthesia. The occurrence of adverse reactions such as hypothermia, lateral recumbency, ataxia, noise sensitivity, vomiting, defaecation, salivation, nystagmus and excitation was observed at the same timepoints. During the recovery period pain scores were lower and sedation scores higher in the sufentanil LA groups. In many dogs acceptable pain and sedation scores persisted during 24 h. Several dogs showed ataxia, lateral recumbency, arousal on auditory stimulation, defaecation, salivation and excitation at several time-points after sufentanil LA administration. Sufentanil LA in addition to sevoflurane anaesthesia offered beneficial dosage-reducing analgesic effects up to 69.8% for thiopental and 78.3% for sevoflurane; although several typical opioid side-effects occurred. To achieve this advantageous dosage-reducing effect 15 min should be respected between sufentanil LA administration and induction of sevoflurane anaesthesia.
... 4 Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA; 5 T... more ... 4 Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA; 5 Taylor Monroe, Gravel Head Farm, Downham Common, Little Downham, Ely, Cambridgeshire CB6 2TY. SIR, We were reassured ...
Twenty adult healthy horses undergoing elective surgery were involved in this prospective, blinde... more Twenty adult healthy horses undergoing elective surgery were involved in this prospective, blinded, clinical study. Horses were randomly allocated to receive a constant rate infusion (CRI) of morphine or dexmedetomidine. After induction, anaesthesia was maintained with isoflurane in oxygen/air and mechanical ventilation applied. The end-tidal isoflurane concentration (F É ISO) was initially set at 0.9% and adjusted by the anaesthetist, to maintain a light surgical plane of anaesthesia, according to an objective flow-chart. The cardiopulmonary function was only minimally different between groups and maintained within clinically normal ranges. Less ketamine was required, F É ISO was lower after 1 h and fewer alterations in the anaesthetic depth were needed in horses receiving dexmedetomidine, with better recoveries. One horse receiving morphine developed post-operative colic and pulmonary oedema and two showed box-walking behaviour. This study showed that a dexmedetomidine CRI produced a more stable anaesthetic depth, reduced isoflurane requirements and better recoveries, without post-operative complications compared with a morphine CRI.
Veterinary and Comparative Orthopaedics and Traumatology, 2006
SummaryThis paper reports the surgical treatment of a tibial fracture in a castrated adult male B... more SummaryThis paper reports the surgical treatment of a tibial fracture in a castrated adult male Belgian Landrace pig of 180 kg. The fracture was repaired using an intramedullary Steinmann pin, combined with cerclage wire and external transfixation. In contrast to other animal species, the fracture repair in the pig was hindered by the short and curved bones, the thick subcutaneous fat layer and the pronounced musculature. Postoperatively, the pig developed an osteomyelitis of the tibia due to pin tract contamination. Despite this complication, the fracture healed acceptably when all fixation material was removed two months after surgery. The infection resolved quickly and a satisfactory clinical result was obtained.
Objective To investigate the anatomy of the ear innervation in horses and develop a new approach ... more Objective To investigate the anatomy of the ear innervation in horses and develop a new approach for the block of the internal and external pinna and acoustic meatus. Study design Prospective, descriptive, cadaveric study. Animals Twenty-five heads and necks from horse cadavers. Methods Phase I: anatomical dissection and dye deposition on 19 heads. With the head positioned in lateral recumbency, 10 mL methylene blue (1:1 sterile water) for the internal auricular and 2 mL for the great auricular nerve block were injected in 21 ears (7 left, 10 right and 2 bilaterally). The anatomy of all the ears (bilaterally) and the accuracy of dye deposition (successful nerve staining defined as < 2 cm) was assessed following dissection. Occurrence of intra-parotid, intra-vascular or intra-neural injection was recorded. Phase II: the same technique and volumes were applied, bilaterally, using a lidocaine 2%:iohexol solution mixture (3:1) in 6 different cadavers. Computed tomography (CT) was performed and the needle position and spread of the mixture evaluated and recorded. Results Phase I: Inter-and intra-individual differences were found in the anatomy of the great auricular nerve, but not in the internal and lateral auricular nerve branches and the caudal auricular nerve. No auriculotemporal nerve was found. Nerve staining was successful in 95% of the cases for the great auricular nerve, 85% of the cases for the internal auricular nerve, and 100% of the cases for the lateral auricular branch and caudal auricular nerve. Failure was observed in horses with abundant peri-auricular fat. No intra-vascular, intra-parotid or intraneural injections occurred. Phase II: A 100% success rate was recorded from CT images.
Veterinary anaesthesia and analgesia, Jan 21, 2014
To investigate the influence of two inspired oxygen fractions (Fi'O2 ) on the arterial oxygen... more To investigate the influence of two inspired oxygen fractions (Fi'O2 ) on the arterial oxygenation in horses anaesthetized with isoflurane. Retrospective, case-control clinical study. Two hundred equine patients undergoing non-abdominal surgery (ASA class 1-2), using a standardized anaesthetic protocol and selected from anaesthetic records of a period of three years, based on pre-defined inclusion criteria. In group O (n = 100), medical oxygen acted as carrier gas, while in group M (n = 100), a medical mixture of oxygen and air (Fi'O2 0.60) was used. Demographic data, Fi'O2 , arterial oxygen tension (PaO2 ) and routinely monitored physiologic data were recorded. The alveolar-arterial oxygen tension difference [P(A-a)O2 ] and PaO2 /Fi'O2 ratio were calculated. The area under the curve, standardized to the anaesthetic duration, was calculated and statistically compared between groups using t-tests or Mann-Whitney tests as appropriate. Categorical data were compared usi...
precision and accuracy were evaluated and the results fell within the ranges specified. The limit... more precision and accuracy were evaluated and the results fell within the ranges specified. The limit of quantification was 0.1 µg/mL for both analytes, whereas limits of detection were 9.6 and 3.5 ng/mL for ketamine and norketamine, respectively. The method was applied on biological samples from a pharmacokinetic study in calves and demonstrated the suitability of the method for this application.
In Belgium and even in northern Europe Rhinosporidium seeberi has not been reported in autochtono... more In Belgium and even in northern Europe Rhinosporidium seeberi has not been reported in autochtonous people or animals. In this paper, the authors report the first observation of laryngeal masses, caused by Rhinosporidium seeberi, in a Belgian Warmblood horse. Moreover, laryngeal rhinosporidiosis is extremely rare since this localisation is only described in four human cases.
Veterinary Clinics of North America: Equine Practice, 2013
Despite the use of balanced anesthesia and fluids, drugs for cardiovascular support are often nee... more Despite the use of balanced anesthesia and fluids, drugs for cardiovascular support are often needed in anesthetized horses. Antimuscarinics can be used to treat bradycardia unrelated to hypertension. Vasopressors can be useful when hypotension is caused by vasodilation and/or when the effect of fluids and inotropes is insufficient. In most cases, however, inotropes, including sympathomimetics, calcium salts, and phosphodiesterase inhibitors, are preferred. Of the β-sympathomimetics, dobutamine remains the agent of choice. Calcium salts are mainly useful in hypocalcemic patients. Phosphodiesterase inhibitors may offer an alternative solution, but more research is needed.
Objective Enoximone is a phosphodiesterase III inhibitor frequently used to improve cardiac outpu... more Objective Enoximone is a phosphodiesterase III inhibitor frequently used to improve cardiac output (CO) in man. As the use of enoximone has not been reported in horses, the effects of this inodilator were examined in isoflurane anaesthetized ponies. Study design Prospective, randomised, experimental study. Conclusions and clinical relevance The present results suggest that in isoflurane anaesthetized ponies, enoximone has beneficial effects on CO and SV without producing significant changes in blood pressure. Despite an increase in _ Qs/ _ Qt, _ DO 2 to the tissues was improved.
Objective To evaluate the combined effects of enoximone and dobutamine on the cardiovascular syst... more Objective To evaluate the combined effects of enoximone and dobutamine on the cardiovascular system and respiratory gas exchange in isofluraneanaesthetized ponies. Study design Prospective, randomized, experimental study. Animals Six ponies (286 ± 52 kg), aged 5.0 ± 1.6 years. Methods After sedation (romifidine 80 lg kg)1), anaesthesia was induced with midazolam (0.06 mg kg)1) and ketamine (2.2 mg kg)1) and maintained with isoflurane in oxygen. The ponies were ventilated to maintain eucapnia. After 90 minutes (=T0), enoximone alone (0.5 mg kg)1) (E) or enoximone, followed by a constant rate infusion of dobutamine (0.5 lg kg)1 minute)1) (ED) for 120 minutes, was administered. Each pony received both treatments in a crossover trial, with at least 2 weeks between treatments. Heart rate (HR), cardiac output (CO), stroke volume (SV), right atrial (RAP), systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP), blood gases, systemic vascular resistance (SVR), oxygen delivery (_ DO 2) and several respiratory gas exchange variables were measured before treatment and until T120. Statistical analysis was based on a mixed model with treatment, time and their interaction as fixed categorical effects, pony as random effect, comparing treatments globally (a = 0.05) and at specific timepoints (Bonferroni-adjusted a = 0.00625). Results Compared to enoximone alone, ED treatment produced an increase in HR, CO, SV, RAP, SAP, DAP, MAP, packed cell volume (PCV) and _ DO 2. The difference was significant from T60 to T120 (except at T80) for HR, throughout the observational period for CO, SAP, MAP, PCV and _ DO 2 , from T40 to T120 for DAP, at T10,T60,T80 and T120 for SV and at T10 and T20 for RAP. Overall decreases occurred in SVR and dead space ventilation (V D /V T). V D /V T was lower at T20 and from T80 to T120. Venous oxygen saturation was increased from T60 onwards. Conclusions and clinical relevance The results suggest that enoximone and dobutamine have additive cardiovascular effects and reduce V D /V T in isoflurane-anaesthetized ponies.
Objective To evaluate the cardiopulmonary effects of two different constant rate infusions (CRI) ... more Objective To evaluate the cardiopulmonary effects of two different constant rate infusions (CRI) of dexmedetomidine (1 and 1.75 lg kg)1 hour)1) in experimental ponies. Animals Six healthy ponies (mean 306 ± SD 71 kg, 7.0 ± 1.6 years). Study design Prospective, randomized, experimental study. Methods After premedication with intravenous (IV) dexmedetomidine (3.5 lg kg)1), anaesthesia was induced (T0) with ketamine (2.2 mg kg)1 IV) and midazolam (0.06 mg kg)1 IV) and maintained with isoflurane (FE¢ISO 1.50%) in 55% oxygen for 150 minutes. Normocapnia was maintained using artificial ventilation. Three ponies received dexmedetomidine CRIs of 1 and 1.75 lg kg)1 hour)1 from T30 to T60 and T90 to T120 respectively. In the other three ponies, the order of the doses was reversed. Continuous monitoring included pulse oximetry, electrocardiography, anaesthetic gas monitoring, arterial and central venous pressures. Cardiac ouput (LiDCO technique) was measured and arterial and venous bloods taken every 15 minutes. Cardiac index (CI), systemic vascular resistance (SVR), arterial and venous oxygen content (CaO 2 , CvO 2) and oxygen delivery (_ DO 2) were calculated. Analysis of variance with separate models for each CRI rate was used to detect differences between values obtained at the end of the CRI and their respective baseline values. A mixed model with these differences as response variable, pony as random effect and treatment and period as fixed effects was applied to find differences between the two CRIs (a = 0.05 for all analyses). Results Heart rate (HR), CI, CaO 2 , CvO 2 and _ DO 2 decreased significantly, while significant increases were found in SVR, systolic arterial pressure and right atrial pressure with both infusion rates. No differences were found between the two dexmedetomidine CRI rates. Conclusions and clinical relevance Although significant, cardiopulmonary effects of the dexmedetomidine CRIs in isoflurane anaesthetized ponies were small, without differences between the two dose rates.
To compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those... more To compare the effects of a constant rate infusion (CRI) of dexmedetomidine and morphine to those of morphine alone on the minimum end-tidal sevoflurane concentration necessary to prevent movement (MACNM ) in ponies. Prospective, randomized, crossover, &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;blinded&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;, experimental study. Five healthy adult gelding ponies were anaesthetized twice with a 3-week washout period. After induction of anaesthesia with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (Fe&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;SEVO 2.5%) in 55% oxygen. Monitoring included pulse oximetry, electrocardiography and measurement of anaesthetic gases, arterial blood pressure and body temperature. The ponies were mechanically ventilated and randomly allocated to receive IV treatment M [morphine 0.15 mg kg⁻¹ (T10-T15) followed by a CRI (0.1 mg kg⁻¹ hour⁻¹)] or treatment DM [dexmedetomidine 3.5 μg kg⁻¹ plus morphine 0.15 mg kg⁻¹ (T10-T15) followed by a CRI of dexmedetomidine 1.75 μg kg⁻¹ hour⁻¹ and morphine 0.1 mg kg⁻¹ hour⁻¹]. At T60, a stepwise MACNM determination was initiated using constant current electrical stimuli at the skin of the lateral pastern region. Triplicate MACNM estimations were obtained and then averaged in each pony. Wilcoxon signed-rank test was used to detect differences in MAC between treatments (α = 0.05). Sevoflurane-morphine MACNM values (median (range) and mean ± SD) were 2.56 (2.01-4.07) and 2.79 ± 0.73%. The addition of a continuous infusion of dexmedetomidine significantly reduced sevoflurane MACNM values to 0.89 (0.62-1.05) and 0.89 ± 0.22% (mean MACNM reduction 67 ± 11%). Co-administration of dexmedetomidine and morphine CRIs significantly reduced the MACNM of sevoflurane compared with a CRI of morphine alone at the reported doses.
Objective To investigate the cardiovascular effects of epidural romifidine in isoflurane-anaesthe... more Objective To investigate the cardiovascular effects of epidural romifidine in isoflurane-anaesthetized dogs. Study design Prospective, randomized, blinded experiment. Animals A total of six healthy adult female Beagles aged 1.25 ± 0.08 years and weighing 12.46 ± 1.48 (10.25-14.50) kg.
Objective To evaluate the effects of a constant rate infusion (CRI) of romifidine on the requirem... more Objective To evaluate the effects of a constant rate infusion (CRI) of romifidine on the requirement of isoflurane, cardiovascular performance and recovery in anaesthetized horses undergoing arthroscopic surgery. Study design Randomized blinded prospective clinical trial. Animals Thirty horses scheduled for routine arthroscopy. Methods After premedication (acepromazine 0.02 mg kg)1 , romifidine 80 lg kg)1 , methadone 0.1 mg kg)1) and induction (midazolam 0.06 mg kg)1 ketamine 2.2 mg kg)1), anaesthesia was maintained with isoflurane in oxygen. Horses were assigned randomly to receive a CRI of saline (group S) or 40 lg kg)1 hour)1 romifidine (group R). The influences of time and treatment on anaesthetic and cardiovascular parameters were evaluated using an analysis of variance. Body weight (t-test), duration of anaesthesia (t-test) and recovery score (Wilcoxon Rank Sum Test) were compared between groups. Significance was set at p < 0.05. Results All but one horse were positioned in the dorsal recumbent position and ventilated from the start of anaesthesia. End tidal isoflurane concentrations were similar in both groups at similar time points and over the whole anaesthetic period. Cardiac output was significantly lower in horses of the R group, but there were no significant differences between groups in cardiac index, body weight or age. All other cardiovascular parameters were similar in both groups. Quality of recovery did not differ significantly between groups, but more horses in group R stood without ataxia at the first attempt. One horse from group S had a problematic recovery. Conclusions and clinical relevance No inhalation anaesthetic sparing effect or side effects were observed by using a 40 lg kg)1 hour)1 romifidine CRI in isoflurane anaesthetized horses under clinical conditions. Cardiovascular performance remained acceptable. Further studies are needed to identify the effective dose of romifidine that will induce an inhalation anaesthetic sparing effect in anaesthetized horses.
Objective To investigate the influence of a dexmedetomidine constant rate infusion (CRI) in horse... more Objective To investigate the influence of a dexmedetomidine constant rate infusion (CRI) in horses anaesthetized with isoflurane. Study design Prospective, randomized, blinded, clinical study. Animals Forty adult healthy horses (weight mean 491 ± SD 102 kg) undergoing elective surgery. Methods After sedation [dexmedetomidine, 3.5 lg kg)1 intravenously (IV)] and induction IV (midazolam 0.06 mg kg)1 , ketamine 2.2 mg kg)1), anaesthesia was maintained with isoflurane in oxygen/air (FiO 2 55-60%). Horses were ventilated and dobutamine was administered when hypoventilation [arterial partial pressure of CO 2 > 8.00 kPa (60 mmHg)] and hypotension [arterial pressure 70 mmHg] occurred respectively. During anaesthesia, horses were randomly allocated to receive a CRI of dexmedetomidine (1.75 lg kg)1 hour)1) (D) or saline (S). Monitoring included end-tidal isoflurane concentration, cardiopulmonary parameters, and need for dobutamine and additional ketamine. All horses received 0.875 lg kg)1 dexmedetomidine IV for the recovery period. Age and weight of the horses, duration of anaesthesia, additional ketamine and dobutamine, cardiopulmonary data (ANOVA), recovery scores (Wilcoxon Rank Sum Test), duration of recovery (t-test) and attempts to stand (Mann-Whitney test) were compared between groups. Significance was set at p < 0.05. Results Heart rate and arterial partial pressure of oxygen were significantly lower in group D compared to group S. An interaction between treatment and time was present for cardiac index, oxygen delivery index and systemic vascular resistance. Endtidal isoflurane concentration and heart rate significantly increased over time. Packed cell volume, systolic, diastolic and mean arterial pressure, arterial oxygen content, stroke volume index and systemic vascular resistance significantly decreased over time. Recovery scores were significantly better in group D, with fewer attempts to stand and significantly longer times to sternal position and first attempt to stand. Conclusions and clinical relevance A dexmedetomidine CRI produced limited cardiopulmonary effects, but significantly improved recovery quality.
Objective To evaluate the cardiovascular effects of a preload of hydroxyethylstarch 6% (HES), pre... more Objective To evaluate the cardiovascular effects of a preload of hydroxyethylstarch 6% (HES), preceding an epidural administration of ropivacaine 0.75% in isoflurane anaesthetized dogs. Animals Six female, neutered Beagle dogs (mean 13.3 ± SD 1.0 kg; 3.6 ± 0.1 years). Study design Randomized experimental cross-over study (washout of 1 month).
Objective To examine the influence of a detomidine constant rate infusion (CRI) on cardiovascular... more Objective To examine the influence of a detomidine constant rate infusion (CRI) on cardiovascular function, isoflurane requirements and recovery quality in horses undergoing elective surgery. Study design Prospective, randomized, blinded, clinical trial. Animals Twenty adult healthy horses. Methods After sedation (detomidine, 10 lg kg)1 intravenously [IV]) and induction of anaesthesia (midazolam 0.06 mg kg)1 , ketamine 2.2 mg kg)1 IV), anaesthesia was maintained with isoflurane in oxygen/air (inspiratory oxygen fraction 55%). When indicated, the lungs were mechanically ventilated. Dobutamine was administered when MAP < 70 mmHg. The horses were randomly allocated to one of two groups and throughout anaesthesia, received either a detomidine (5 lg kg)1 hour)1) (D) or saline (S) CRI, with the anaesthetist unaware of the treatment. Monitoring included end-tidal isoflurane concentration, arterial pH, PaCO 2 , PaO 2 , dobutamine administration rate, heart rate (HR), arterial pressure, cardiac index (CI), systemic vascular resistance (SVR), stroke index and oxygen delivery index (_ DO 2 I). For recovery from anaesthesia, all horses received 2.5 lg kg)1 detomidine IV. Recovery quality and duration were recorded in each horse. For statistical analysis, ANOVA, Pearson chi-square and Wilcoxon rank sum tests were used as relevant. Results Heart rate (p = 0.0176) and _ DO 2 I (p = 0.0084) were lower and SVR higher (p = 0.0126) in group D, compared to group S. Heart rate (p = 0.0011) and pH (p = 0.0187) increased over time. Significant differences in isoflurane requirements were not detected. Recovery quality and duration were comparable between treatments. Conclusions and clinical relevance A detomidine CRI produced cardiovascular effects typical for a 2agonists, without affecting isoflurane requirements, recovery duration or recovery quality.
Objective To evaluate the cardiopulmonary effects of sufentanil long acting (SLA) in sevofluranea... more Objective To evaluate the cardiopulmonary effects of sufentanil long acting (SLA) in sevofluraneanaesthetized dogs. Study Design Randomized prospective study. Animals Forty female dogs (beagles) aged 1-2 years, weighing 11.97 ± 1.40 kg. Materials and methods The dogs were divided into five groups of eight. Two control groups were used: group A received intramuscular (IM), SLA (50 lg kg)1) alone, while group B received the SLA vehicle followed by sevoflurane anaesthesia for 90 minutes. In the other groups, SLA (50 lg kg)1 IM) was given immediately before (group C 0), 15 minutes before (group D 15) or 30 minutes (group E 30) before induction [with intravenous (IV) thiopental] of sevoflurane anaesthesia lasting for 90 minutes. Heart rate, arterial blood pressure, respiratory rate (f r), arterial oxygen haemoglobin saturation and end-tidal sevoflurane concentration (FE¢SEVO) were measured every 10 minutes during anaesthesia and at 2, 4 and 24 hours after induction (not FE¢SEVO). Acid-base and blood gas analyses were performed. Results Sufentanil LA reduced heart rate and increased arterial CO 2 tensions during anaesthesia. Respiratory depression was least in group E 30 compared with groups C 0 and D 15. Bradycardia was present for at least 24 hours. Respiratory rate was least in group B although arterial O 2 and CO 2 tension values were acceptable up to 24 hours after anaesthesia. Conclusions Pre-anaesthetic medication with SLA moderately aggravated the cardiopulmonary effects of sevoflurane. Clinical relevance In spite of a moderate depressant effect on cardiorespiratory parameters, SLA may be of use as pre-anaesthetic medication before sevoflurane anaesthesia in dogs. Intermittent positive pressure ventilation may occasionally be necessary.
The purpose of the present study was to determine the most effective time interval between the ad... more The purpose of the present study was to determine the most effective time interval between the administration of sufentanil long acting (LA) and the induction of sevoflurane anaesthesia in dogs. The occurrence of sedation, analgesia and other marked side-effects were evaluated in addition to the possible dosage-reducing effect of sufentanil on sevoflurane in dogs. Forty clinically normal beagles aged 1-2 years and weighing between 8.4 and 13.6 kg were included. Two control groups were used: one group of dogs (A) received sufentanil LA (50 lg/kg i.m.) and a second group (B) the sufentanil vehicle followed by standard inhalation anaesthesia of 90 min. After premedication with sufentanil LA immediately before (C 0), 15 min (D 15) or 30 min (E 30) prior to induction with thiopental (i.v.) the dogs were anaesthetized for 90 min with sevoflurane in oxygen. Pain and sedation scores were evaluated every 10 min during sevoflurane anaesthesia and at 2 (T 120), 4 (T 240) and 24 h (T 1440) after initiation of anaesthesia. The occurrence of adverse reactions such as hypothermia, lateral recumbency, ataxia, noise sensitivity, vomiting, defaecation, salivation, nystagmus and excitation was observed at the same timepoints. During the recovery period pain scores were lower and sedation scores higher in the sufentanil LA groups. In many dogs acceptable pain and sedation scores persisted during 24 h. Several dogs showed ataxia, lateral recumbency, arousal on auditory stimulation, defaecation, salivation and excitation at several time-points after sufentanil LA administration. Sufentanil LA in addition to sevoflurane anaesthesia offered beneficial dosage-reducing analgesic effects up to 69.8% for thiopental and 78.3% for sevoflurane; although several typical opioid side-effects occurred. To achieve this advantageous dosage-reducing effect 15 min should be respected between sufentanil LA administration and induction of sevoflurane anaesthesia.
... 4 Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA; 5 T... more ... 4 Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA; 5 Taylor Monroe, Gravel Head Farm, Downham Common, Little Downham, Ely, Cambridgeshire CB6 2TY. SIR, We were reassured ...
Twenty adult healthy horses undergoing elective surgery were involved in this prospective, blinde... more Twenty adult healthy horses undergoing elective surgery were involved in this prospective, blinded, clinical study. Horses were randomly allocated to receive a constant rate infusion (CRI) of morphine or dexmedetomidine. After induction, anaesthesia was maintained with isoflurane in oxygen/air and mechanical ventilation applied. The end-tidal isoflurane concentration (F É ISO) was initially set at 0.9% and adjusted by the anaesthetist, to maintain a light surgical plane of anaesthesia, according to an objective flow-chart. The cardiopulmonary function was only minimally different between groups and maintained within clinically normal ranges. Less ketamine was required, F É ISO was lower after 1 h and fewer alterations in the anaesthetic depth were needed in horses receiving dexmedetomidine, with better recoveries. One horse receiving morphine developed post-operative colic and pulmonary oedema and two showed box-walking behaviour. This study showed that a dexmedetomidine CRI produced a more stable anaesthetic depth, reduced isoflurane requirements and better recoveries, without post-operative complications compared with a morphine CRI.
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