Monitoring of the oxygen saturation of horses during halothane anesthesia using pulse oximetry in the nasal septum]

The use of pulse oximetry for on-line monitoring of oxygen saturation of arterial blood using a probe on the nasal septum is described in the horse. When compared to the results of blood gas analysis an excellent correlation between the two methods for measuring oxygen saturation is found. Nevertheless a discrepancy between the values for oxygen saturation provided by either method is found. This can lead to misinterpretation of oxygen saturation values generated by the pulse oximeter. The cause of this discrepancy is not clear but differences in measuring principle, presence of dyshemoglobins and differences in absorption characteristics of hemoglobin are to be ruled out as major contributors. Contrary to findings in several other animal species occasionally double counting of pulse frequency by the pulse oximeter is seen.     

Respiratory monitoring: arterial blood gas analysis, pulse oximetry, and end-tidal carbon dioxide analysis

The use of arterial blood gas analysis, pulse oximetry, and capnography has become commonplace in the assessment of veterinary patients. Blood gas analysis allows for the qualitative and quantitative assessment of both metabolic and respiratory acid-base problems, including the interrelationships between ventilation, oxygenation, and metabolic conditions. Blood gas analysis is a useful adjunct to clinical patient assessment and other diagnostics in determining appropriate therapy for specific and complex conditions. Both pulse oximetry and capnography are useful monitoring tools. However, they have technical limitations and cannot comprehensively evaluate patient oxygenation and ventilation. Pulse oximetry and capnography are not replacements for arterial blood gas analysis, but rather serve as adjunctive monitoring tools.     

Evaluation of Pulse Oximetry as a Continuous Monitoring Technique in Critically Ill Dogs in the Small Animal Intensive Care Unit

To assess the clinical applicability of pulse oximetry in the intensive care setting, a comparison was made of arterial hemoglobin saturation values determined by in vitro oximetry (SaO₂) and pulse oximetry (SpO₂) in 21 critically ill dogs. Single SaO₂ measurements were compared to simultaneously obtained SpO₂ readings. The correlation between these two methods was statistically significant (r = 0.8944, p = 0.0001). In addition, heart rates read by the pulse oximeter were compared to simultaneously obtained electrocardiograms (ECG). The correlation between these two methods was statistically significant (r = 0.9966, p = 0.0001). The pulse oximeter was easy to use, and recorded trends in oxygenation virtually instantaneously. Pulse oximetry appears to be an accurate and practical technique for the continuous non-invasive monitoring of oxygenation in critically ill dogs in the intensive care unit.     

Evaluation of intramuscular butorphanol, azaperone, and medetomidine and nasal oxygen insufflation for the chemical immobilization of white-tailed deer, Odocoileus virginianus

Chemical immobilization of wildlife often includes opioids or cyclohexamines. These substances are problematic as a result of their required storage, handling, and record-keeping protocols. A potentially useful alternative sedation protocol includes a combination of butorphanol, azaperone, and medetomidine (BAM: 0.43 mg/kg butorphanol, 0.36 mg/kg azaperone, 0.14 mg/kg medetomidine). One risk of wildlife immobilization with any drug combination is hypoxemia. This may be of particular importance when using an alpha 2 agonist such as medetomidine because of its powerful vasoconstrictive effect. In this prospective study, the BAM combination was evaluated for chemical immobilization of white-tailed deer. Additionally, selected physiologic parameters associated with BAM immobilization, including oxygen saturation via pulse oximetry and arterial blood gas measurement, with and without nasal insufflation of oxygen at a relatively low flow of 3 L/min, were evaluated. The BAM combination resulted in a predictable onset of sedation, with a mean induction time to lateral recumbency of 9.8 +/- 3.6 min. All deer recovered smoothly within a range of 5-20 min after reversal with intramuscular administration of naltrexone, atipamazole, and tolazoline (NAT). Clinically relevant decreases in arterial partial pressure of oxygen (PaO2) and oxygen saturation (SpO2) were observed in animals not receiving supplemental oxygen, while both parameters significantly improved for oxygen-supplemented deer. Pulse oximetry with this protocol was an unreliable indicator of oxygen saturation. In this study, altitude, recumbency, hypoventilation, butorphanol- and medetomidine-specific effects, as well as the potential for alpha 2 agonist-induced pulmonary changes all may have contributed to the development of hypoxemia. Overall, capture of white-tailed deer with the BAM/NAT protocol resulted in excellent chemical immobilization and reversal. Because the BAM combination caused significant hypoxemia that is unreliably detected by pulse oximetry but that may be resolved with nasal oxygen insufflation, routine use of oxygen supplementation is recommended.     

Accuracy of pulse oximetry and capnography in healthy and compromised horses during spontaneous and controlled ventilation

The objective of this prospective clinical study was to evaluate the accuracy of pulse oximetry and capnography in healthy and compromised horses during general anesthesia with spontaneous and controlled ventilation. Horses anesthetized in a dorsal recumbency position for arthroscopy (n = 20) or colic surgery (n = 16) were instrumented with an earlobe probe from the pulse oximeter positioned on the tip of the tongue and a sample line inserted at the Y-piece for capnography. The horses were allowed to breathe spontaneously (SV) for the first 20 min after induction, and thereafter ventilation was controlled (IPPV). Arterial blood, for blood gas analysis, was drawn 20 min after induction and 20 min after IPPV was started. Relationships between oxygen saturation as determined by pulse oximetry (S_pO₂), arterial oxygen saturation (S_aO₂)_, arterial carbon dioxide partial pressure (P_aCO₂), and end tidal carbon dioxide (P_(et)CO₂), several physiological variables, and the accuracy of pulse oximetry and capnography, were evaluated by Bland–Altman or regression analysis. In the present study, both S_pO₂ and P_(et)CO₂ provided a relatively poor indication of S_aO₂ and P_aCO₂, respectively, in both healthy and compromised horses, especially during SV. A difference in heart rate obtained by pulse oximetry, ECG, or palpation is significantly correlated with any pulse oximeter inaccuracy. If blood gas analysis is not available, ventilation to P_(et)CO₂ of 35 to 45 mmHg should maintain the P_aCO₂ within a normal range. However, especially in compromised horses, it should never substitute blood gas analysis.     

Evaluation of the reliability of pulse oximetry,at different attachment sites,to detect hypoxaemia in immobilized impala (Aepyceros melampus)

ObjectiveEvaluation of the reliability of pulse oximetry at four different attachment sites compared to haemoglobin oxygen saturation measured by a co-oximeter and calculated by a blood gas analyser in immobilized impala.Study designRandomized crossover study.AnimalsA total of 16 female impala.MethodsImpala were immobilized with etorphine or thiafentanil alone, or etorphine in combination with a novel drug. Once immobilized, arterial blood samples were collected at 5 minute intervals for 30 minutes. Then oxygen was insufflated (5 L minute⁻¹) intranasally at 40 minutes and additional samples were collected. A blood gas analyser was used to measure the arterial partial pressure of oxygen and calculate the oxygen haemoglobin saturation (cSaO₂); a co-oximeter was used to measure the oxygen haemoglobin saturation (SaO₂) in arterial blood. Pulse oximeter probes were attached: under the tail, to the pinna (ear) and buccal mucosa (cheek) and inside the rectum. Pulse oximeter readings [peripheral oxygen haemoglobin saturation (SpO₂) and pulse quality] were recorded at each site and compared with SaO₂ and cSaO₂ using Bland-Altman and accuracy of the area root mean squares (A_rms) methods to determine the efficacy. P value < 0.05 was considered significant.ResultsPulse quality was ‘good’ at each attachment site. SpO₂ measured under the tail was accurate and precise but only when SaO₂ values were above 90% (bias = 3, precision = 3, A_rms = 4). The ear, cheek and rectal probes failed to give accurate or precise readings (ear: bias = −4, precision = 14, A_rms = 15; cheek: bias = 12, precision = 11, A_rms = 16; and rectum: bias = 5, precision = 12, A_rms = 13).Conclusions and clinical relevanceIn order to obtain accurate and precise pulse oximetry readings in immobilized impala, probes must be placed under the tail and SaO₂ must be above 90%. Since SaO₂ values are usually low in immobilized impala, pulse oximeter readings should be interpreted with caution.     

Pulse oximetry and end tidal carbon dioxide monitoring.

Noninvasive monitoring of cardiopulmonary function through pulse oximetry and capnography provides immediate and important information for the clinician. These monitors are not a replacement for vigilant attention to the patient, however; they should be used in conjunction with arterial blood gas analysis and serial physical examinations to ensure that the continuous readings are accurate and make clinical sense.     

Evaluation of accuracy of pulse oximetry in newborn calves

In human medicine, pulse oximetry is widely used to measure non-invasively and accurately the percentage of oxygen saturation of arterial haemoglobin (SpO(2)). Recently, pulse oximetry has been used in calves, but its accuracy has not been evaluated in newborn calves. The purpose of this study was to evaluate the accuracy of a pulse oximeter in newborn calves by comparing SpO(2) with arterial oxyhaemoglobin saturation (SaO(2)) obtained by use of a blood gas analyser. Fifty-five newborn calves were investigated from birth to 20 days old. Pulse oximetry readings and arterial blood samples were performed 5, 15, 30, 45, 60 min, 2, 3, 6, 12, 24 h and 1 and 3 weeks after birth. The transmission-type sensors of the pulse oximeter were fixed at the recommended site in the bovine species (at the base of the calf tail, where the skin had been shaved and was not pigmented) and arterial blood samples were withdrawn from the subclavian artery and analysed for SaO(2). Five-hundred paired data of SaO(2) and mean SpO(2)(mSpO(2)) were collected. Linear regression of the pooled data indicated a highly significant correlation of mSpO(2) with SaO(2) (r = 0.87;P< 0.001; mSpO(2) = 15.8 + 0.84 SaO(2)). The overall data bias value was positive (+2.1%), which indicated that the pulse oximeter tended to overestimate the SaO(2). The bias value for each SaO(2) category tended to become higher for lower ranges of SaO(2). Precision was also lower when SaO(2) values were low. The lower the SaO(2) value, the higher the positive bias (overestimation) and the lower the precision. These results suggest that pulse oximetry provides a relatively accurate non-invasive, immediate and portable method to monitor SaO(2) and to evaluate objectively the pulmonary function effectiveness in newborn calves during their adaptation to extra-uterine life.     

Evaluation of Masimo signal extraction technology pulse oximetry in anaesthetized pregnant sheep

ObjectiveEvaluation of the accuracy of Masimo signal extraction technology (SET) pulse oximetry in anaesthetized late gestational pregnant sheep.Study designProspective experimental study.AnimalsSeventeen pregnant Merino ewes.MethodsAnimals included in study were late gestation ewes undergoing general anaesthesia for Caesarean delivery or foetal surgery in a medical research laboratory. Masimo Radical-7 pulse oximetry (SpO₂) measurements were compared to co-oximetry (SaO₂) measurements from arterial blood gas analyses. The failure rate of the pulse oximeter was calculated. Accuracy was assessed by Bland &; Altman's (2007) limits of agreement method. The effect of mean arterial blood pressure (MAP), perfusion index (PI) and haemoglobin (Hb) concentration on accuracy were assessed by regression analysis.ResultsForty arterial blood samples paired with SpO₂ and blood pressure measurements were obtained. SpO₂ ranged from 42 to 99% and SaO₂ from 43.7 to 99.9%. MAP ranged from 24 to 82 mmHg, PI from 0.1 to 1.56 and Hb concentration from 71 to 114 g L^?1. Masimo pulse oximetry measurements tended to underestimate oxyhaemoglobin saturation compared to co-oximetry with a bias (mean difference) of ?2% and precision (standard deviation of the differences) of 6%. Accuracy appeared to decrease when SpO₂ was <75%, however numbers were too small for statistical comparisons. Hb concentration and PI had no significant effect on accuracy, whereas MAP was negatively correlated with SpO₂ bias.Conclusions and clinical relevanceMasimo SET pulse oximetry can provide reliable and continuous monitoring of arterial oxyhaemoglobin saturation in anaesthetized pregnant sheep during clinically relevant levels of cardiopulmonary dysfunction. Further work is needed to assess pulse oximeter function during extreme hypotension and hypoxaemia.     

Pulse Oximetry For Estimation Of Oxygenation In Dogs With Experimental Pneumothorax

The purpose of this study was the evaluation of pulse oximetry for estimating the oxygen saturation of hemoglobin (S_pO₂) in dogs with pneumothorax. Values for measured by pulse oximetry with transducers on the tongues and toes of six dogs were compared with saturation values (S_aO₂) computed from arterial oxygen tensions (P_aO₂) during experimentally induced pneumothorax (30,45, and 60 ml/kg of ambient air in the pleural space). Values for S_pO₂, S_aO₂, and P_aO₂ decreased with increasing volume of air. Compared to computed S_aO₂ values, S_pO₂ values obtained from the tongue tended to be less variable than those obtained from the toe, but both locations gave valuable information. Pulse oximetry appears to be a useful, relatively inexpensive method of estimating hemoglobin saturation in dogs with experimentally induced pneumothorax, and it appears to have clinical application in management of critical or traumartized dogs.     

Comparison of abomasal luminal gas pressure and volume and perfusion of the abomasum in dairy cows with left displaced abomasum or abomasal volvulus

OBJECTIVE: To compare abomasal luminal gas pressure and volume and perfusion of the abomasum in dairy cows with a left displaced abomasum (LDA) or abomasal volvulus (AV). ANIMALS: 40 lactating dairy cows (25 with an LDA and 15 with an AV). PROCEDURE: Abomasal luminal gas pressure and volume and pulse oximetry values for the caudal portion of the dorsal ruminal sac and abomasal wall were measured during laparotomy. Abomasal perfusion was assessed on the basis of abomasal O2 saturation (pulse oximetry) before correction of the LDA or AV. Abomasal perfusion was also assessed after correction of the LDA or AV by measuring venous O2 saturation in the right gastroepiploic vein and calculating the abomasal oxygen-extraction ratio. RESULTS: Abomasal luminal gas pressure and volume were higher in cattle with an AV than in cattle with an LDA. Abomasal O2 saturation was lower and abomasal oxygen-extraction ratio higher in cattle with an AV, compared with values in cattle with an LDA. In cows with an AV, lactate concentration in the gastroepiploic vein was greater than that in a jugular vein, whereas no difference in lactate concentrations was detected in cows with an LDA. Abomasal luminal gas pressure was positively correlated (r, 0.51) with plasma lactate concentration in the gastroepiploic vein and negatively correlated (r, -0.32) with abomasal O2 saturation determined by use of pulse oximetry. CONCLUSIONS AND CLINICAL RELEVANCE: Abomasal perfusion decreases as luminal pressure increases in cattle with an AV or LDA.     

The cardiovascular and respiratory effects of medetomidine and thiopentone anaesthesia in dogs breathing at an altitude of 1486 m

The purpose of this study was to evaluate the cardio-respiratory effects of the combination of medetomidine and thiopentone followed by reversal with atipamezole as a combination for anaesthesia in 10 healthy German Shepherd dogs breathing spontaneously in a room at an altitude of 1486 m above sea level with an ambient air pressure of 651 mmHg. After the placement of intravenous and intra-arterial catheters, baseline samples were collected. Medetomidine (0.010 mg/kg) was administered intravenously and blood pressure and heart rate were recorded every minute for 5 minutes. Thiopentone was then slowly administered until intubation conditions were ideal. An endotracheal tube was placed and the dogs breathed room air spontaneously. Blood pressure, pulse oximetry, respiratory and heart rate, capnography, blood gas analysis and arterial lactate were performed or recorded every 10 minutes for the duration of the trial. Thiopentone was administered to maintain anaesthesia. After 60 minutes, atipamezole (0.025 mg/kg) was given intramuscularly. Data were recorded for the next 30 minutes. A dose of 8.7 mg/kg of thiopentone was required to anaesthetise the dogs after the administration of 0.010 mg/kg of medetomidine. Heart rate decreased from 96.7 at baseline to 38.5 5 minutes after the administration of medetomidine (P < 0.05). Heart rate then increased with the administration of thiopentone to 103.2 (P < 0.05). Blood pressure increased from 169.4/86.2 mmHg to 253.2/143.0 mmHg 5 minutes after the administration of medetomidine (P < 0.05). Blood pressure then slowly returned towards normal. Heart rate and blood pressure returned to baseline values after the administration of atipamezole. Arterial oxygen tension decreased from baseline levels (84.1 mmHg) to 57.8 mmHg after the administration of medetomidine and thiopentone (P < 0.05). This was accompanied by arterial desaturation from 94.7 to 79.7% (P < 0.05). A decrease in respiratory rate from 71.8 bpm to 12.2 bpm was seen during the same period. Respiratory rates slowly increased over the next hour to 27.0 bpm and a further increases 51.4 bpm after the administration of atipamezole was seen (P < 0.05). This was maintained until the end of the observation period. Arterial oxygen tension slowly returned towards normal over the observation period. No significant changes in blood lactate were seen. No correlation was found between arterial saturation as determined by blood gas analysis and pulse oximetry. Recovery after the administration of atipamezole was rapid (5.9 minutes). In healthy dogs, anaesthesia can be maintained with a combination of medetomidine and thiopentone, significant anaesthetic sparing effects have been noted and recovery from anaesthesia is not unduly delayed. Hypoxaemia may be problematic. Appropriate monitoring should be done and oxygen supplementation and ventilatory support should be available. A poor correlation between SpO2 and SaO2 and ETCO2 and PaCO2 was found.     

Examination of potential methods to predict pulmonary arterial pressure score in yearling beef cattle

Susceptibility of beef cattle to high altitude disease (HAD) is of major importance to economic and genetic selection on high elevation ranches. However, currently the best indicator of HAD susceptibility is the pulmonary arterial pressure (PAP) test, a test with high cost and invasive nature. Therefore, 2 experiments were undertaken to determine whether emerging technologies that predict blood components could be used to predict the PAP score in yearling Angus cattle. In Exp. 1, 39 yearling Angus bulls were used to determine if a relationship existed between PAP score and 10 blood components provided by a hemogram using whole blood or oxygen saturation as predicted by pulse oximetry in nonanesthetized cattle measured rectally or orally. Three of the hemogram values (packed cell volume, hemoglobin concentration, and red cell distribution width) were correlated (P < 0.10) with the PAP score. Prediction equations for PAP score were generated using the hemogram values and resulted in R2 values of 0.375 and 0.305 for the regression model using all of values and the best 2-variable model, respectively. Pulse oximetry was able to provide oxygen saturation predictions rectally or orally; however, the predicted values were not correlated with the PAP score (P > 0.10) or with each other (P > 0.10). In Exp. 2, 84 yearling Angus cattle (62 bulls, 22 heifers) were used to evaluate the ability of a portable clinical analyzer to predict the PAP score using 11 blood components from a sample of whole blood evaluated at the processing chute. The portable clinical analyzer was able to provide values for all of the 11 blood components; however, none of the predicted values were correlated with the PAP score (P > 0.10). In these preliminary experiments, 3 blood component values provided via the hemogram were the only variables both correlated with the PAP score and able to contribute to the development of a useful PAP prediction equation that could reduce the cost of traditional measures of HAD susceptibility. Future research is needed to determine whether additional blood components or emerging blood analysis technologies are able to accurately predict the PAP score in beef cattle.     

Practicality, Usefulness, and Limits of Pulse Oximetry in Critical Small Animal Patients

Pulse oximetry holds the promise of wide application for monitoring and assessing pulmonary function in small animal patients. Although the saturation as read by pulse oximetry (SpO2) has previously been shown to be accurate in healthy dogs, its accuracy and usefulness have not been demonstrated in critical small animal patients. The present study assessed the accuracy and usefulness of a pulse oximeter (Ohmeda Biox 3740, Ohmeda, Louisville, CO) in a small animal intensive care unit. The instrument yielded readings in 48 of 51 attempts in 33 animals (25 dogs, 8 cats). Criteria were developed to reject spurious readings; when these criteria were applied, the actual calculated SaO2 differed from the SpO2 by O.26 +2.2%, with a correlation of 0.87 (p<0.0001). The 95% confidence interval was +4.4%, comparable to the accepted level in humans. No ill effects from SpO2 were apparent in the patients, and the instrument was useful in monitoring the progress of critical animals. However, uncritical use of the oximeter could have led to gross patient mismanagement, as SpO2 readings as much as 29% different from SaO2 were sometimes obtained.     

Physiologic evaluation of capture and anesthesia with medetomidine-zolazepam-tiletamine in brown bears (Ursus arctos)

Physiologic variables during anesthesia with medetomidine-zolazepam-tiletamine were evaluated in 52 free-ranging brown bears (Ursus arctos) darted from a helicopter and in six captive brown bears darted at a zoo. During anesthesia, rectal temperature, respiratory rate, heart rate, and pulse oximetry derived hemoglobin oxygen saturation were recorded. Arterial blood samples were collected and immediately analyzed for evaluation of pulmonary gas exchange, acid-base status, and selected hematologic and plasma variables. At the end of anesthesia, atipamezole was administered intramuscularly at five times the medetomidine dose. Capture-induced hyperthermia and lactic acidemia were documented in free-ranging bears. Hypoxemia during anesthesia was documented in both free-ranging and captive bears. In free-ranging bears, rectal temperature, heart rate, lactate, hematocrit, and hemoglobin decreased significantly during anesthesia, whereas partial pressure of arterial carbon dioxide, pH, potassium, and glucose increased. Yearlings had a significantly higher heart rate, pH, base excess, bicarbonate, and glucose, and had a significantly lower rectal temperature, sodium, hematocrit, and hemoglobin when compared with subadult and adult brown bears. In conclusion, alterations in pulmonary gas exchange and acid-base status in brown bears during anesthesia with medetomidine-zolazepam-tiletamine with the doses and capture methods used in this study were identified. Oxygen supplementation is recommended to counteract hypoxemia during anesthesia.     

Treatment of hypoxemia during xylazine-tiletamine-zolazepam immobilization of wapiti.

Hypoxemia is a commonly observed complication during the chemical immobilization of wild ruminants. If severe and left untreated, it can predispose animals to arrhythmias, organ failure, and capture myopathy. The following prospective study was designed to measure the degree of hypoxemia in wapiti that were immobilized with a combination of xylazine and tiletamine-zolazepam and to assess the response to nasal oxygen therapy. Pulse oximetry and arterial blood gas analysis were used to assess the degree of hypoxemia prior to nasal insufflation of oxygen and to demonstrate any beneficial effects of this intervention. All wapiti exhibited mild to marked hypoxemia (PaO2 = 43 +/- 11.8 mmHg) prior to treatment and showed marked improvement after 5 minutes of nasal insufflation of oxygen at 10 L/min (PaO2 = 207 +/- 60 mmHg). This inexpensive, noninvasive technique has great benefit in treating clinical hypoxemia under field conditions, and we recommend that nasal insufflation of oxygen be implemented during xylazine-tiletamine-zolazepam-induced immobilization of wapiti and other wild ruminants.     

Steady-state response characteristics of a pulse oximeter on equine intestine

The steady-state response characteristics of a pulse oximeter were evaluated on intestinal segments of seven clinically normal halothane-anesthetized horses. Arterial oxygen tension greater than 200 mm of Hg, end tidal carbon dioxide from 30 to 35 mm of Hg, and systemic mean arterial pressure greater than 70 mm of Hg were maintained throughout the recording periods. Values for percentage of pulse oximeter oxygen saturation, pulsatile blood flow, and percentage of signal strength were recorded from jejunum, ileum, cecum, left ventral colon, left dorsal colon, and descending colon. Probe placement on intestinal segments was recorded as over or not over visible subserosal or transmural vessels. There was no significant difference between median values on the basis of vessel codes for pulse oximeter oxygen saturations, pulsatile flow, and signal strength. Median values recorded for pulse oximeter oxygen saturation were 93% from jejunum and ileum and 95% from cecum, left ventral colon, left dorsal colon, and descending colon; median values for pulsatile flow were 576 from jejunum, 560 from ileum, 560 from cecum, 574 from left ventral colon, 578 from left dorsal colon, and 560 from descending colon; median values for signal strength were 50% from jejunum, 67.5% from ileum, 60% from cecum, 75% from left ventral colon, 50% from left dorsal colon, and 52.5% from descending colon. Median values obtained from each anatomic location were not significantly different for pulsatile flow or signal strength. Median pulse oximetry oxygen values recorded from jejunum and ileum were significantly lower than values obtained from other intestinal segments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cardiopulmonary assessment of medetomidine, ketamine, and butorphanol anesthesia in captive Thomson's gazelles (Gazella thomsoni).

This investigation evaluated the cardiopulmonary effects of medetomidine, ketamine, and butorphanol anesthesia in captive juvenile Thomson's gazelles (Gazella thomsoni). Butorphanol was incorporated to reduce the dose of medetomidine necessary for immobilization and minimize medetomidine-induced adverse cardiovascular side effects. Medetomidine 40.1 +/- 3.6 microg/kg, ketamine 4.9 +/- 0.6 mg/kg, and butorphanol 0.40 +/- 0.04 mg/kg were administered intramuscularly by hand injection to nine gazelles. Times to initial effect and recumbency were within 8 min postinjection. Cardiopulmonary status was monitored every 5 min by measuring heart rate, respiratory rate, indirect blood pressure, end-tidal CO2, and indirect oxygen-hemoglobin saturation by pulse oximetry. Venous blood gases were collected every 15 min postinjection. Oxygen saturations less than 90% in three gazelles suggested hypoxemia. Subsequent immobilized gazelles were supplemented with intranasal oxygen throughout the anesthetic period. Sustained bradycardia (<60 beats per minute, as compared with anesthetized domestic calves, sheep, and goats) was noted in eight of nine gazelles. Heart and respiratory rates and rectal temperatures decreased slightly, whereas systolic, mean, and diastolic blood pressure values were consistent over the anesthetic period. Mild elevations in end tidal CO2 and PCO2 suggested hypoventilation. Local lidocaine blocks were necessary to perform castrations in all seven of the gazelles undergoing the procedure. Return to sternal recumbency occurred within 7 min and return to standing occurred within 12 min after reversal with atipamezole (0.2 +/- 0.03 mg/kg) and naloxone (0.02 +/- 0.001 mg/kg). Medetomidine, ketamine, and butorphanol can be used to safely anesthetize Thomson's gazelles for routine, noninvasive procedures. More invasive procedures, such as castration, can be readily performed with the additional use of local anesthetics.     

Blood oxygen concentration of fast-growing and slow-growing broiler chickens, and chickens with ascites from right ventricular failure.

Percent hemoglobin oxygen saturation was measured with a pulse oximeter in 6-week-old slow-growing (light) and fast-growing (heavy) male broiler chickens and those with ascites from right ventricular failure (RVF). Pulse rate and percent oxygen saturation were read from the ulnar artery just proximal to the carpus. Percent oxygen saturation was significantly (P less than or equal to 0.0001) higher in light chickens (mean 91.6%) than in heavy chickens (mean 86.0%), and the percent oxygen saturation was significantly (P less than or equal to 0.0001) higher in both groups with normal hearts than in the group with RVF from valvular insufficiency (mean 62.1%). All RVF chickens and those with normal hearts were confirmed at necropsy. Light chickens were males with leg deformity or stunting and were 20-50% lighter than the heavy chickens.     

Co-oximetry in clinically healthy dogs and effects of time of post sampling on measurements

Objectives : Co‐oximetry is a complex and valuable laboratory method that measures haemoglobin species and oxygenation status by multi‐wavelength spectrophotometry. The purpose of this study was to establish reference intervals for clinically healthy dogs and to determine the effect of time of analyses and sex of animals on the accuracy of results. Methods : Blood was collected from 27 healthy adult dogs of various breeds and sex. Co‐oximetry was performed on a CCX co‐oximeter that measures eight haemoglobin and oxygen transport related parameters: carboxyhaemoglobin (COHb), deoxyhaemoglobin (HHb), oxyhaemoglobin (O₂Hb), methaemoglobin (MetHb), total haemoglobin (tHb), oxygen saturation (SO₂%), oxygen content (O₂Ct) and oxygen capacity (O₂Cap). Results : Results obtained after 2 and 4 hours were not significantly different from those obtained immediately after sampling. But after 48 hours, the results for total haemoglobin, oxygen saturation, oxyhaemoglobin, oxygen content and oxygen capacity were significantly lower, and carboxyhaemoglobin and deoxyhaemoglobin values were significantly higher than determination immediately after sampling. Gender had no significant impact on co‐oximetry values. Clinical Significance : Co‐oximetry offers several advantages compared with other methods, including ease of use, increased accuracy and greater differentiation among haemoglobin species.