Indirect measurement of blood pressure using a pulse oximeter in isoflurane anesthetized dogs

Objective: To determine the accuracy of indirect blood pressure (BP) measurements obtained with a pulse oximeter as compared with direct measurements in dogs under isoflurane anesthesia. The Doppler and oscillometric BP monitors were included for comparison. Design: Prospective, experimental study. Animals: Twenty healthy dogs (23 ± 8 kg) anesthetized for research or teaching. Interventions: Dogs were anesthetized with propofol or thiopental and maintained using positive pressure ventilation with isoflurane in 100% O₂. Random adjustment of BP was achieved by inhalant adjustment or dopamine infusion to achieve low (≤85 mmHg), normal (90–120 mmHg), or high systolic BP (≥125 mmHg). Triplicate measurements for BP were taken with direct (dorsal pedal artery), Doppler (forelimb), oscillometric (same forelimb), and plethysmographic (pulse oximeter on tongue) methods. Measurements and main results: Using regression analysis and a modified Bland–Altman's technique, the lowest bias was achieved with the Doppler. Systolic BP readings at low, normal, and high BP were within 10 mmHg of direct recordings 95%, 70%, and 30% of the time for pulse oximetry; 95%, 85%, and 55% of the time for Doppler; 42%, 65%, and 30% of the time for oscillometric determination, respectively. Oscillometric mean BP readings were within 10 mmHg of direct measurements 53%, 60%, and 45% of the time, respectively. Conclusions: The pulse oximeter is an acceptable method for measuring BP in anesthetized dogs if assessment of trends is sufficient. All indirect methods showed greater bias and poorer precision at high BP. The Doppler may be the preferred indirect method.     

Systolic blood pressure of clinically normal and conscious cats determined by an indirect Doppler method in a clinical setting

The purposes of the present study were to determine the systolic blood pressure (SBP) of clinically normal and conscious cats, and to set up reference values of feline SBP for subsequent clinical application. SBPs were measured in 53 healthy cats using an ultrasonic Doppler device. The mean SBP was 133.6 +/- 16.0 mmHg (range, 110.0-180.0 mmHg). The distribution of SBP values was not significantly affected by factors such as breed, body condition score, or age (P>0.05), but SBP values of female cats were significantly lower and more variable than those of males (t test, P=0.004; F test, P<0.001). Feline SBP between 114.3 mmHg and 149.5 mmHg was considered indicative of normotension. SBP values higher than 159.3 mmHg were defined as hypertension, and those less than 104.5 mmHg were determined as hypotension.     

Determination of reference arterial blood pressure values by indirect methods for Kangal dogs

OBJECTIVES: To obtain reference arterial blood pressure values from Kangal dogs, a local giant breed found in Turkey. METHODS: Arterial blood pressure measurements were obtained from 48 healthy Kangal dogs using oscillometric and Doppler techniques. The ages of the dogs ranged from two to 96 months, with a mean (sd) age of 36 (16) months. RESULTS: The effect of age on systolic, diastolic and mean arterial pressures determined by the oscillometric technique and on systolic pressure determined by the Doppler technique was significant (P<0.001). Blood pressure was found to be higher in mature dogs compared with that in immature dogs. The effect of sex and the interaction between age and sex were not significant (P>0.05). There was a direct relationship between age and oscillometric systolic, diastolic and mean arterial pressures and Doppler systolic arterial blood pressure both in the whole group and the immature group (P<0.05). Correlation between age and systolic arterial blood pressure measured either by oscillometric or Doppler techniques was not significant in the mature group. CLINICAL SIGNIFICANCE: The Kangal dog is bred in various countries including Turkey. It is known that giant breed dogs, such as the Kangal dog, are predisposed to cardiovascular disease. Canine arterial blood pressure values are highly breed and age dependent, so a reference value for any other breed is inappropriate for Kangal dogs. Therefore, it is important to measure arterial blood pressure of Kangal dogs.     

Effect of long-term adaptation on indirect measurements of systolic blood pressure in conscious untrained beagles

To evaluate the effect of an adaptation period on systemic blood pressure readings, systolic blood pressure was measured in 12 young adult untrained beagles over several weeks by means of a Doppler flow detector and oscillometric devices. The pressure decreased gradually and significantly, and levelled out after 14 days. The median (range) of values obtained by Doppler were 166 (149 to 200) mmHg initially, 145 (119 to 176) mmHg on day 9, 138 (118 to 165) mmHg on day 10, 127 (111 to 139) mmHg on day 35, 124 (115 to 143) mmHg on day 94 and 127 (114 to 142) mmHg on day 161. All the later measurements were significantly lower than the initial measurement. Male dogs had higher blood pressures than females on each occasion. The blood pressure readings obtained with one of the oscillometric devices and the Doppler device were comparable and correlated significantly.     

Indirect measurement of systemic blood pressure in conscious dogs in a clinical setting

The present study compared 2 indirect methods, Doppler sphygmomanometry and oscillometry, for measurement of the systemic blood pressure level in 100 conscious, client-owned dogs in a clinical setting on 2 separate occasions. The mean systemic blood pressure values, measured by Doppler sphygmomanometry on 2 separate occasions, were 156 +/- 38.2 mmHg and 150 +/- 34.1 mmHg, respectively. Using oscillometry, the mean systolic blood pressure values were 138 +/- 36.9 mm Hg and 133 +/- 33.5 mm Hg on 2 separate occasions. There were significant differences between the systemic blood pressure readings for both methods on the same occasion (P<0.001). The coefficients of variance from 5 consecutive measurements in the same dog obtained by Doppler sphygmomanometry on the 2 separate occasions were 4.1 +/- 3.2% and 3.1 +/- 1.7%; that of the oscillometric method on the 2 separate occasions were 18.7 +/- 11.3% and 17.2 +/- 12.5%. The coefficients of variance of these 2 methods were statistically different on each occasion (P<0.001). Five consecutive systemic blood pressure readings were obtained for each dog within 6 min on both occasions using Doppler sphygmomanometry. More than 15 min was required to complete 5 consecutive systemic blood pressure readings by oscillometric sphygmomanometry for all dogs on each occasion. The results of this study indicate that Doppler sphygmomanometry provides more efficient and precise measurements of the systemic blood pressure level than oscillometric testing in conscious dogs in a clinical setting.     

A comparison of CAT Doppler and oscillometric Memoprint machines for non-invasive blood pressure measurement in conscious cats

Indirect blood pressure measurements were compared in 28 conscious cats using Doppler and oscillometric blood pressure-measuring devices. Ten cats were used to compare Doppler measurements between two examiners and 18 cats were used to compare Doppler and oscillometric measurements. The Doppler machine obtained systolic and diastolic blood pressure readings in 100% and 51% of attempts, respectively. With the oscillometric machine, systolic and diastolic blood pressure readings were obtained in 52% of the attempts. With the Doppler, measures of mean systolic blood pressure between two examiners were positively correlated, but there was no correlation for diastolic blood pressure measures. When comparing the results obtained by Doppler and oscillometric machines there was no significant difference between mean systolic blood pressure readings, but the oscillometric machine produced significantly higher estimates of diastolic blood pressure. In both cases, the standard deviations for the oscillometric machine were considerably larger than those for the Doppler machine. The first reading of systolic blood pressure obtained with the Doppler machine was an excellent predictor of the mean of five readings, but this was not so for the oscillometric machine. It took less than 5 min to obtain five readings in 37.5% of cases with the Doppler machine but this was true for only 5% of cases with the oscillometric machine. Two cats with ophthalmological lesions consistent with systemic hypertension were identified. In these two patients, systolic blood pressure measurements were between 200 and 225 mmHg when measured by Doppler, and between 140 and 150 mmHg when measured by the oscillometric machine. This suggests that a lower reference range for normal systolic blood pressure values should be used for the oscillometric device.     

Doppler echocardiographic prediction of pulmonary hypertension in West Highland white terriers with chronic pulmonary disease

BACKGROUND: Pulmonary hypertension (PH) is commonly diagnosed by Doppler echocardiography (DE) of tricuspid regurgitation (TR). However, TR may be absent or difficult to measure. HYPOTHESIS: Doppler-derived systolic time intervals of pulmonary artery (PA) flow may be used to predict PH in dogs. ANIMALS: Seventy-three healthy dogs and 45 West Highland white terriers (WHWT) with interstitial pulmonary disease (IPD). METHODS: Echocardiographic studies, including determination of right ventricular acceleration time (AT), ejection time (ET), and AT : ET ratio; right ventricular shortening fraction (RV-SF); and TR velocity, were performed. Pulmonary hypertension was defined by TR >3.1 m/s. RESULTS: In healthy WHWT, AT (median, range) was 73 ms (53 to 104) and AT : ET was 0.40 (0.28 to 0.55). AT : ET was minimally affected by age (R2 = 0.04, 95% confidence interval [CI] 0.01-0.07, P < .001) but not by heart rate, body weight, or RV-SF. In all WHWT with TR, AT and AT : ET were inversely related to calculated systolic PA pressure (R2 = 0.52, 95% CI 0.42-0.62, P < .001 and R2 = 0.36, 95% CI 0.29-0.42, P = .001). Clinical cutoffs to predict systolic PH were defined for AT (58 ms; sensitivity [Se] 88% and specificity [Sp] 80%) and AT : ET (0.31; Se 73% and Sp 87%). CONCLUSION AND CLINICAL IMPORTANCE: PH is common in WHWT with IPD. Analysis of right ventricular AT and AT : ET may be predictive of PH and should be particularly useful if TR is absent.     

Comparison of high definition oscillometric and Doppler ultrasound devices with invasive blood pressure in anaesthetized dogs

Objective To use the American College of Veterinary Internal Medicine (ACVIM) validation criteria to evaluate the performance of high definition oscillometric (HDO) and Doppler blood pressure measurement techniques against invasive blood pressure measurements in anaesthetized dogs. Study design Prospective clinical study. Animals Twenty client‐owned dogs. Materials and Methods Invasive blood pressure was measured using a catheter inserted into a pedal artery and an electronic transducer. The sites of cuff placement for the HDO measurements were the mid antebrachium or the proximal tail and, for the Doppler technique, the distal tibia. Agreement between invasive and non‐invasive blood pressure measurements was estimated by the Bland–Altman method. Results Only 10% and 34% of Doppler measurements were within 10 and 20 mmHg of invasive blood pressure values, respectively. The Doppler device failed to meet the ACVIM validation criteria for blood pressure measurement devices. The best agreement between HDO and invasive blood pressure measurement technique was observed for mean arterial blood pressure (MAP); 67% and 95% of readings were within 10 and 20 mmHg of invasive blood pressure values respectively. In addition, 52% and 87% of diastolic arterial blood pressure (DAP) measurements were within 10 and 20 mmHg of invasive readings. High definition oscillometric readings did not meet ACVIM recommended limits for SAP. Conclusion and clinical relevance The Doppler technique overestimated and the HDO device showed limited agreement with invasive blood pressure measurement in anaesthetized dogs. High definition oscillometry met most of the ACVIM requirements for MAP and DAP while the Doppler technique did not.     

Occurrence of systemic hypertension in dogs with acute kidney injury and treatment with amlodipine besylate

Objectives : To describe the occurrence of systemic hypertension in dogs with acute kidney injury and the efficacy of amlodipine besylate for its treatment. Methods : This retrospective study included 52 dogs with acute kidney injury (2007 to 2008) grouped based on the use of amlodipine in their treatment. Systemic blood pressure was measured with an oscillometric device at admission, before, during, and after amlodipine therapy. Results : Occurrence of systolic systemic hypertension (≥160 mmHg) and severe systolic systemic hypertension (≥180 mmHg) was 37% and 15% at admission and increased with hospitalisation to 81% and 62%, respectively. Twenty‐two dogs were treated with amlodipine, at a median daily dosage of 0·38 mg/kg (interquartile range 0·28 to 0·49) divided in one to two applications per day. Amlodipine therapy was associated with a decrease in systolic systemic blood pressure of 24 mmHg (12 to 34) and a correction of severe systemic hypertension in 10 of 11 dogs within 24 hours. Overall, 73% of the dogs survived with a significantly lower proportion of survivors in treated compared to non‐treated dogs (59% versus 83%, respectively, P=0·05). Clinical Significance : Results of this study reveal that systemic hypertension is common in canine acute kidney injury and that treatment with amlodipine is beneficial in reducing systemic hypertension. The potential effect of amlodipine on global outcome requires prospective assessment.     

Receiver operating characteristic-based assessment of a serological test used to detect Johne’s disease in Israeli dairy herds

The overall accuracy of an enzyme-linked immunosorbent assay (ELISA) used to detect Johne's disease at herd level was explored in relation to an imperfect test (fecal culture) in 57 Israeli dairy herds. Receiver-operating characteristic (ROC) analysis indicated an area under the curve (AUC) that corresponded to a test accuracy of 82.0% (69.5% to 90.9%; 95% confidence), with optimized herd sensitivity and herd specificity of 70.4% and 83.3%, respectively; and predictive values of 79.2 (+) and 75.8% (-). The optimal ELISA cutoff was 3.16% (> 3.16% seropositive cows in a herd), which was associated with likelihood ratios (LR) of 4.22 (+LR) and 0.36 (-LR), and post-test probabilities of 0.79 (+) and 0.17 (-). For herds with < or = 200 cows (n = 19 herds), the 95% confidence interval (CI) for the AUC was 0.62-0.97 and the optimal cutoff was 3.33% (HSe = 87.5, HSp = 81.8); for herds with > 200 but < or = 270 cows (n = 19 herds), the 95% AUC CI was 0.62-0.97 and the optimal cutoff was 1.13% (HSe = 90.0, HSp = 77.78); and for herds with > 270 cows (n = 19 herds), the 95% AUC CI was 0.69-0.99 and the optimal cutoff was 0.7% (HSe = 100.0, HSp = 70.0). The AUC was not influenced by across-herd prevalence [R2 (adjusted) = 0.0, P > 0.05]. Findings may be applied to facilitate targeted sampling of herds similar to those evaluated. For instance, a test cutoff of 0.76% could be considered for "ruling disease in," while a cutoff of 3.7% could be used for "ruling disease out." Caveats that may influence this analysis are discussed.     

Evaluation of oscillometric and Doppler ultrasonic methods of indirect blood pressure estimation in conscious dogs

To assess the accuracy and precision of indirect measurements of systemic arterial blood pressure (BP), results obtained with an oscillometric device (BPo) and a Doppler ultrasonic device (BPud) were compared with those obtained by direct radiotelemetry (BPrt) in 12 conscious beagles. The correlation between indirectly obtained and directly measured values for BP parameters ranged widely for the different indirect methods and sites of cuff placement, with R2 between 0.001 and 0.901. Both indirect methods underestimated all BP parameters, the degree of underestimation increasing at higher values for the BP. The highest correlation occurred when estimates were the average of 5 values consecutively obtained with the oscillometric device and cuff placement at the coccygeal artery (R2 = 0.854 for mean BPo, 0.886 for systolic BPo, and 0.901 for diastolic BPo; P < 0.0001 for all parameters) or with the ultrasonic Doppler device at the metatarsal arteries (R2 = 0.810 for systolic BPud; P < 0.0001). Multiple consecutively obtained values are advised, as this approach improves the reliability of indirect BP measurements. The strong correlation between directly measured values and estimates derived as the average of 5 consecutive indirectly obtained values indicates that the latter approach provides a useful estimate of BP in conscious dogs and is likely to be useful in monitoring disease progress and treatment in dogs with abnormal BP.     

Diagnostic value of echo-Doppler and tissue Doppler imaging in dogs with pulmonary arterial hypertension

BACKGROUND: Diagnosis of pulmonary arterial hypertension (PAH) relies on Doppler measurement of pulmonic and tricuspid regurgitation (TR). However, these are not always detectable. HYPOTHESIS: Tissue Doppler imaging (TDI), a novel noninvasive ultrasound technique, provides indirect but sensitive and specific assessment of elevated systolic pulmonary artery pressure (SPAP) in dogs. ANIMALS: One hundred and five dogs with TR. METHODS: Prospective observational study. Dogs were categorized as presenting normal (group 1, n = 45), mildly increased (group 2, n = 19), or moderately to severely increased (group 3, n = 41) SPAP, based on TR peak velocities (< 2.5, 2.5-3.0, and > 3.0 m/s, respectively). Ten quantitative echo-Doppler- and TDI-derived variables were assessed, including the main pulmonary arterial diameter to aortic diameter ratio, pulmonary flow acceleration time, and acceleration-to-ejection time ratio, the Tei index of right ventricular function, and 6 longitudinal basal right ventricular TDI variables. RESULTS: A significant correlation was observed between SPAP and each of the 10 tested variables (P < .05). Conventional echo-Doppler variables were less discriminating than the TDI for predicting increased SPAP. The combined systolic and diastolic right TDI index had the highest sensitivity and specificity (89% and 93% respectively, for a cutoff of 11.8 cm/s) and could discriminate between dogs in group 1 from dogs in group 2. CONCLUSIONS AND CLINICAL IMPORTANCE: TDI provided effective predictors of systolic PAH and demonstrated that both alterations in right-sided systolic and diastolic myocardial function can occur with mild increases in SPAP.     

Clinical comparison of three methods to measure blood pressure in nonsedated dogs

OBJECTIVE: To determine arterial blood pressure in client-owned dogs, using direct arterial puncture, oscillometry, and Doppler ultrasonography in a clinical setting. DESIGN: Prospective study. ANIMALS: 8 clinically normal client-owned dogs. PROCEDURE: Blood pressures of nonsedated dogs were measured simultaneously, using each of the 3 methods. Mean values obtained were compared with published mean values. Ability of noninvasive methods (Doppler ultrasonography and oscillometry) to accurately predict results of the invasive method, and relationships between blood pressure and age, body weight, and degree of patient anxiety were determined. RESULTS: Calculated ranges of values (mean +/- 2 SD) determined by direct arterial puncture were: systolic pressure, 114 to 194 mm Hg; diastolic pressure, 66 to 102 mm Hg; and mean pressure, 85 to 129 mm Hg. Ranges determined by use of oscillometry were: systolic, 110 to 190 mm Hg; diastolic, 35 to 107 mm Hg; and mean, 78 to 138 mm Hg. Ultrasonographic and oscillometric values did not accurately predict direct values, but mean values of systolic and mean pressures were similar among methods. Relationships were not detected between age or body weight and blood pressure. Significant differences in blood pressure were not detected between anxious and nonanxious dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Mean values of systolic, diastolic, and mean arterial blood pressure measured in nonsedated client-owned dogs, using invasive and noninvasive methods in a clinical setting, are comparable with those determined for acclimatized, trained, or sedated dogs. However, results of noninvasive methods may not accurately reflect direct values.     

Efficacy of atenolol as a single antihypertensive agent in hyperthyroid cats

beta-Adrenergic blockers, particularly atenolol, are often recommended for the tachycardia and hypertension that accompany hyperthyroidism; however, the effects of monotherapy with atenolol on both systolic blood pressure (SBP) and heart rate (HR) have not been reported. Twenty hyperthyroid cats with SBP > or = 160 mmHg were studied retrospectively to investigate the SBP and HR lowering effects of atenolol. Median pre-treatment SBP and HR for all cats were 186.5 mmHg and 231 beats/min, respectively. All cats were treated with atenolol at a dosage of 1-2 mg/kg PO q 12h for a minimum of 5 days prior to reassessment and treatment with radioactive iodine. SBP and HR both decreased following atenolol therapy in this group of cats to median values of 171.5 mmHg (P=0.0088) and 185/min (P=0.0003). However, when successful clinical control of hypertension was defined as a post-treatment SBP < 160 mmHg, atenolol monotherapy was ineffective in 70% of the cases. There was no statistically significant difference in baseline serum total thyroxine or atenolol dosage between clinical responders and non-responders. While atenolol effectively reduces HR in most cats with hyperthyroidism, elevated SBP is poorly controlled, and the addition of another vasodilator such as amlodipine or an angiotensin converting enzyme inhibitor is needed to treat associated hypertension.     

Doppler echocardiography-derived evidence of pulmonary arterial hypertension in dogs with degenerative mitral valve disease: 86 cases (2001-2005)

OBJECTIVE: To determine the prevalence of Doppler echocardiography-derived evidence of pulmonary arterial hypertension (DEE-PAH) in dogs with mitral valve disease (MVD) classified according to the International Small Animal Cardiac Health Council (ISACHC) heart failure classification scheme and various echocardiographic and Doppler indices of MVD severity. DESIGN: Retrospective case series. ANIMALS: 617 dogs examined from 2001 to 2005 with MVD in ISACHC classes I to III. PROCEDURES: Dogs were examined echocardiographically. Criteria used for systolic and diastolic DEE-PAH were detection of high tricuspid (> or = 2.5 m/s) and telediastolic pulmonic (> or = 2.0 m/s) valvular peak regurgitant jet velocities, respectively, by use of continuous-wave Doppler echocardiography. RESULTS: 86 (13.9%) dogs with MVD had a diagnosis of DEE-PAH. Severity and prevalence of DEE-PAH increased with ISACHC class (3.0%, 16.9%, 26.7%, and 72.2% prevalences for ISACHC classes Ia, Ib, II, and III, respectively). A significant correlation between systolic or diastolic pulmonary arterial pressure and left atrial-to-aortic diameter ratio (LA/Ao) was detected. Doppler echocardiography-derived evidence of pulmonary arterial hypertension was detected in 18 dogs with values of LA/Ao within reference range, all of which had moderate (n = 2 dogs) or severe (16) mitral valve regurgitation on color Doppler imaging. CONCLUSIONS AND CLINICAL RELEVANCE: The prevalence and degree of DEE-PAH were related to the severity of MVD. Changes associated with DEEPAH may be detected in early stages of the disease, but only in dogs with severe mitral valve regurgitation.     

Evaluation of oscillometric and Doppler ultrasonic devices for blood pressure measurements in anesthetized and conscious dogs

Two non-invasive blood pressure (NIBP) devices (oscillometry and Doppler) were compared to invasive blood pressure using a Bland–Altman analysis, in anesthetized and conscious dogs. When considering the systolic arterial pressure only during general anesthesia, both NIBP devices slightly underestimated the systolic arterial blood pressure however the precision and the limits of agreement for the Doppler were of a greater magnitude. This indicates a worse clinical performance by the Doppler. The performance of both NIBP devices deteriorated as measured in conscious animals. In general, for the oscillometric device, determination of invasive diastolic and mean arterial pressures was better than the invasive systolic arterial pressure. Overall, the oscillometric device satisfied more of the criteria set by the American College of Veterinary Internal Medicine consensus statement. Based upon these results, the oscillometric device is more reliable than the Doppler in the determination of blood pressure in healthy medium to large breed dogs.     

Spectral waveform analysis of intranodal arterial blood flow in abnormally large superficial lymph nodes in dogs

OBJECTIVE: To evaluate pulsed-wave Doppler spectral parameters as a method for distinguishing between neoplastic and inflammatory peripheral lymphadenopathy in dogs. SAMPLE POPULATION: 40 superficial lymph nodes from 33 dogs with peripheral lymphadenopathy. PROCEDURES: 3 Doppler spectral tracings were recorded from each node. Spectral Doppler analysis including assessment of the resistive index, peak systolic velocity-to-end diastolic velocity (S:D) ratio, diastolic notch velocity-to-peak systolic velocity (N:S) ratio, and end diastolic velocity-to-diastolic notch velocity ratio was performed for each tracing. Several calculation methods were used to determine the Doppler indices for each lymph node. After the ultrasonographic examination, fine needle aspirates or excisional biopsy specimens of the examined lymph nodes were obtained, and lymphadenopathy was classified as either inflammatory or neoplastic (lymphomatous or metastatic) via cytologic or histologic examination. Results of Doppler analysis were compared with cytologic or histopathologic findings. RESULTS: The Doppler index with the highest diagnostic accuracy was the S:D ratio calculated from the first recorded tracing; a cutoff value of 3.22 yielded sensitivity of 91%, specificity of 100%, and negative predictive value of 89% for detection of neoplasia. Overall diagnostic accuracy was 95%. At a sensitivity of 100%, the most accurate index was the N:S ratio calculated from the first recorded tracing; a cutoff value of 0.45 yielded specificity of 67%, positive predictive value of 81%, and overall diagnostic accuracy of 86.5%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that noninvasive Doppler spectral analysis may be useful in the diagnosis of neoplastic versus inflammatory peripheral lymphadenopathy in dogs.     

Importance of uniform cuff application for equine blood pressure measurement

Seventeen horses were used to determine the variances associated with blood pressure cuff application (Sp2) and with other inherent errors (So2). Systolic pressure values had Sp2 = 3.9 mmHg and So2 = 5.6 mmHg, while diastolic pressure values had Sp2 = 1.1 mmHg and So2 = 4.4 mmHg. Thus, to be considered different, two blood pressure means (in mmHg), each derived from three readings, had to differ by at least 3.9 for systolic pressure and 3.4 for diastolic pressure when all readings were made without cuff displacement; 6.8 for systolic pressure and 4.6 for diastolic pressure when the cuff was reapplied between, but not during, measurement of each mean; and 5.0 for systolic pressure and 3.8 for diastolic pressure when the cuff was reapplied between all readings. It was concluded that uniform cuff application is readily achieved.     

Examining heterogeneity in the diagnostic accuracy of culture and PCR for Salmonella spp. in swine: a systematic review/meta-regression approach

The accuracy of bacterial culture and PCR for Salmonella in swine was examined through systematic review of existing primary research in this field. A replicable search was conducted in 10 electronic databases. All steps of the review were conducted by two reviewers: to identify relevant publications, to assess their methodological soundness and reporting, and to extract raw data or reported test accuracy estimates. Meta-analyses and meta-regression were performed: to evaluate pooled estimates of test sensitivity (Se) and specificity (Sp), to identify variables explaining the variation in reported test estimates, and to evaluate the association between these variables and reported test Se and Sp. Twenty-nine studies were included in the review. Unique test evaluations reported in these 29 studies were categorized according to the type of test comparison: culture versus culture (n = 134 test evaluations) and PCR versus culture (n = 21). We identified significant heterogeneity among evaluations for each test category. For culture, more heterogeneity was caused by differences in individual test protocols (52%) than overall differences between studies (16%). Enrichment temperature, study population, agar and enrichment type were significantly associated with variation in culture Se. Furthermore, interaction between enrichment temperature and enrichment type was detected. For PCR, most of the heterogeneity was caused by overall differences between studies (65-70%); sample type and study size were associated with variation in reported PCR Se and Sp. The overall methodological soundness and/or reporting of primary studies included in this review were poor, with variable use of reference standards, and consistent lack of the use or reporting of blinding, randomization and subject (sample) selection criteria. Consequently, the food safety and veterinary public health research community should formally consider ways for standardizing the conduct and reporting of this type of research.     

Evaluation of a Portable Meter to Measure Ketonemia and Comparison with Ketonuria for the Diagnosis of Canine Diabetic Ketoacidosis

Background: The diagnosis of canine diabetic ketoacidosis (DKA) usually is based on measurement of urinary acetoacetate (ketonuria). In humans, this test is less sensitive and specific than blood 3-β-hydroxybutyrate (ketonemia) evaluation.
Hypothesis: Ketonemia measurement using a portable meter is more accurate than ketonuria determination with a dipstick to diagnose canine DKA.
Animals: Seventy-two client-owned diabetic dogs with ketonemia, ketonuria, or both.
Methods: Prospective observational study. Based on blood bicarbonate concentration and anion gap, dogs were divided into 2 groups: patients with DKA ( n = 25); patients with diabetic ketosis ( n = 47). Sensitivity, specificity, and positive and negative likelihood ratio (LR) at different cut-off points were determined for both ketonemia and ketonuria. Receiver operating characteristic (ROC) analysis was used to assess the accuracy of each diagnostic test to diagnose DKA.
Results: With regard to ketonemia, cut-off values of 2.3 and 4.3 mmol/L revealed 100% sensitivity and 100% specificity, respectively, whereas cut-off values of 2.8 and 3.5 mmol/L showed a −LR of 0.05 and a + LR of 13.16, respectively. With regard to ketonuria, a cut-off value of 1+ revealed 92% sensitivity, 40% specificity, and −LR of 0.20, whereas a cut-off value of 3+ revealed 44% sensitivity, 94% specificity, and +LR of 6.89. The areas under the ROC curves for the ketonemia and ketonuria tests were significantly different (0.97 and 0.81, respectively, P = .003).
Conclusions and Clinical Importance: Measurement of ketonemia is accurate and more effective than measurement of ketonuria to diagnose canine DKA.