Evaluation of accuracy of pulse oximetry in dogs.

The accuracy of a pulse oximeter was evaluated over a wide range of arterial oxygen and carbon dioxide tensions, using 2 probes (finger probe and ear probe) and 2 monitoring sites (tongue and tail) in anesthetized dogs. The arterial oxygen saturation of hemoglobin (SaO2) measured directly with a multiwavelength spectrophotometer was compared with saturation estimated by pulse oximetry (SpO2). Linear regression analysis of the pooled data from 399 simultaneous measurements of SpO2 and SaO2 indicated a highly significant correlation of SpO2 with SaO2 (r = 0.97; P less than or equal to 0.0001). Although the mean difference (+/- SD) between SpO2 and SaO2 for pooled data was small (-0.06 +/- 6.8%), SpO2 tended to underestimate high SaO2 values (greater than or equal to 70%) and to overestimate low SaO2 values (less than 70%). When SaO2 values were greater than or equal to 70%, the ear probe applied to the tail was less accurate (produced a significantly greater SpO2-SaO2 difference) than the ear probe on the tongue, or the finger probe at either site. When SaO2 values were less than or equal to 50%, the finger probe applied at the tail was more accurate (produced significantly smaller SpO2-SaO2 differences) than the ear probe at either site. When SaO2 values were less than or equal to 70%, high arterial carbon dioxide tension (greater than or equal to 60 mm of Hg) was associated with greater overestimation of SaO2.     

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.     

Evaluation of veterinarian and veterinary student knowledge and clinical use of pulse oximetry

We hypothesized that veterinarians and veterinary students may lack key knowledge about pulse oximetry, which may result in this type of patient monitor not being used on appropriate patient populations or to its full capabilities. A questionnaire was developed to assess an individual's knowledge and understanding of pulse oximetry. Residents and specialists in anesthesiology and critical care at several academic institutions were surveyed first to assess the questionnaire for clarity and to serve as a control group. General veterinary practitioners (GPs) attending continuing education courses at the University of Georgia were surveyed over a 24-month period. Students entering their senior year anesthesiology rotation at the University of Georgia were also surveyed. Residents and specialists (69% correct responses) scored significantly higher than senior students (46%), who scored significantly higher than GPs (34%). Only 15% of GPs and 21% of senior students reported that they had received training in pulse oximetry in school. Those who had received training scored significantly higher than those who did not. Many GPs did not report using a pulse oximeter on their critical patients under anesthesia, a group that would be expected to benefit from its use. Veterinarians have a poor understanding about how pulse oximetry works, the information provided by pulse oximetry, and how to best apply it to their patients. Furthermore, the respondents did not use pulse oximeters in a manner that would derive the most information and result in the greatest benefit to the patient relative to the cost of the instrument. Didactic training in veterinary curricula and during continuing education opportunities continues to be necessary in order to produce veterinarians, who have an understanding of the technologies available that can be used to improve patient care.     

The use of pulse oximetry in clinical veterinary anaesthesia

A commercial human pulse oximeter was used in several species to measure heart rate and arterial oxygen saturation (SaO₂), and the results compared with those from an ECG and bench oximeter. The heart rates were always the same, but differences in the SaO₂ ranged between 4.2 per cent to 10.3 per cent. Correlation coefficients between the two SaO₂ measurement techniques ranged from 0.81 to 0.94, depending on the species investigated.     

Fractures of the femur in newborn calves

A retrospective study of femoral fractures in 77 calves revealed that most occurred in the femoral shaft or in the proximal physis, with thin cortices and periosteal stripping significant problems in fractures of the femoral shaft. Most cases were related to forced extraction, with more left femurs being affected than right. The existence of concurrent disease reduced the success rate by 50% and, when significant additional trauma was present, no calves survived. When all cases were considered regardless of condition, the “longterm” success rate was 43%.     

Evaluation of a combined transcutaneous carbon dioxide pressure and pulse oximetry sensor in adult sheep and dogs

OBJECTIVE: To evaluate a combined transcutaneous carbon dioxide pressure (tcPCO(2)) and pulse oximetry sensor in sheep and dogs. ANIMALS: 13 adult sheep and 11 adult dogs. PROCEDURES: During inhalation anesthesia, for the first 10 minutes following sensor placement, arterial blood gas was analyzed and tcPCO(2) was recorded every 2 minutes. Subsequently, the animals were hyper-, normo-, and hypoventilated. The simultaneously obtained tcPCO(2) and PaCO(2) values were analyzed by use of Bland-Altman statistical analysis. RESULTS: Mean +/- SD overall difference between tcPCO(2) and PaCO(2) 10 minutes after sensor application was 13.3 +/- 8.4 mm Hg in sheep and 8.9 +/- 12 mm Hg in dogs. During hyper-, normo-, and hypoventilation, mean difference (bias) and precision (limits of agreement [bias +/- 2 SD]) between tcPCO(2) and PaCO(2) values were 13.2 +/- 10.4 mm Hg (limits of agreement, -7.1 and 33.5 mm Hg) in sheep and 10.6 +/- 10.5 mm Hg (limits of agreement, -9.9 and 31.2 mm Hg) in dogs, respectively. Changes in PaCO(2) induced by different ventilation settings were detected by the tcPCO(2) sensor with a lag (response) time of 4.9 +/- 3.5 minutes for sheep and 6.2 +/- 3.6 minutes for dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The tcPCO(2) sensor overestimated PaCO(2) in sheep and dogs and followed changes in PaCO(2) with a considerable lag time. The tcPCO(2) sensor might be useful for noninvasive monitoring of changes but cannot be used as a surrogate measure for PaCO(2).     

Rotavirus infection in newborn calves. I. Evaluation trials of certain enzymes in faeces

The purpose of this work was to investigate the relationship between rotavirus infection, diagnosed in faeces using the serological test, in calves with diarrhoea and the activity of lysozyme, alpha-amylase, lipase and trypsin in the same material. The faeces were taken from 28 sick and 1 healthy animals, aged from 1 to 5 days, for microbiological and enzymatic examination. No correlation was found between lysozyme activity in faeces and rotavirus infection. Similar results were obtained with the other enzymes.     

Hematologic values in newborn beef calves.

Hematologic values were determined in 35 beef calves at birth, at 24 and 48 hours, and in 22 of these calves at 3 weeks after birth. Thirty calves did not have clinical signs of disease throughout the 3-week period. Variables that changed significantly over time in these healthy calves included hematocrit, RBC count, hemoglobin concentration, mean cell volume, mean cell hemoglobin concentration, WBC count, neutrophil-to-lymphocyte ratio, and plasma total protein and serum immunoglobulin concentrations. Of the 35 calves, 5 had clinical signs of disease at 3 weeks. Comparison of hematologic values from these calves with values for healthy calves revealed significant differences at each sample collection time, although disease was not evident at the 3 early sample times. The band neutrophil count and the neutrophil-to-lymphocyte ratio differed between the 2 groups at birth. At 24 hours, the monocyte count was higher in the 5 ill calves. At 48 hours, total leukocyte, mature neutrophil, and monocyte counts, and neutrophil-to-lymphocyte ratio also were higher in the 5 calves. At 3 weeks when clinical signs of disease were detectable in the 5 calves, the total leukocyte, band neutrophil, and mature neutrophil counts, neutrophil-to-lymphocyte ratio, and plasma total protein and fibrinogen concentrations were higher.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of colostral IgG1 absorption in newborn calves after treatment with alkalinizing agents.

The effects of alkalinizing agents, administered prior to feeding colostrum, on blood-gas and acid-base values and on absorption of IgG1 were determined in 40 newborn Holstein calves. Two treatments, sodium bicarbonate (3 mEq/kg of body weight, IV) and doxapram HCl (2 mg/kg, IV), were evaluated, using a randomized complete-block experimental design. These treatments resulted in significant (P less than 0.01) alteration of blood-gas and acid-base values, generally in the direction of normal values for adult cattle. Significant least squares mean effects were detected for sodium bicarbonate treatment on blood pH (+ 0.04 units, P less than 0.01), PCO2 (+ 4.1 mm of Hg, P less than 0.01), and HCO3 concentration (+ 4.4 mEq/L, P less than 0.01). Significant least squares mean effects were detected for doxapram HCl treatment on blood pH (+ 0.06 pH units, P less than 0.01) and PCO2 (-5.2 mm of Hg, P less than 0.01). Absorption of colostral IgG1 was not affected by the treatments given or by the altered blood-gas and/or acid-base status.     

Pharmacokinetics of enrofloxacin in newborn and one-week-old calves

The pharmacokinetic behaviour of enrofloxacin was compared in four one-day-old and four one-week-old calves in order to find out if there were any age-related differences. Mean volume of distribution ( V _d(ss)) and clearance ( Cl ) were significantly smaller in newborn calves: V _d(ss) was 1.8 and 2.3 L/kg, while clearance was 0.19 and 0.39 L/kg.h in newborn and one-week-old calves, respectively. Mean elimination half-life ( t _1/2β) did not differ significantly in newborn and in one-week-old calves: mean t _1/2β was 6.6 h and 4.9 h, respectively. Enrofloxacin was metabolized to ciprofloxacin both by newborn and one-week-old calves, but the maximum concentration ( C _max) of ciprofloxacin was lower and the time when maximum concentration was reached ( t _max) later in newborn calves. We conclude that the dosage of enrofloxacin should be adjusted according to age when administered to very young calves.