Comparison of direct and indirect blood pressure measurements in anesthetized dogs.

The precision and accuracy of an indirect oscillometric blood pressure measurement technique (Dinamap 8100) was assessed in 11 anesthetized Beagle dogs weighing 8 to 11.5 kg. Direct blood pressure measurements were made by catheterization of the lingual artery, and simultaneous indirect measurements were determined by placing a cuff over the median artery (midradial area). Blood pressure measurements at 2 different planes of anesthesia (light and deep) were recorded in triplicate. At a light plane of anesthesia, the Dinamap 8100 underestimated diastolic and mean arterial pressure, and at a deep anesthetic plane overestimated systolic pressure. The indirect technique had good repeatability of systolic pressures. Regression analysis for the 2 techniques showed excellent correlation (r = 0.93). The results indicate that the indirect oscillometric blood pressure measurement technique provides a good estimate of systolic, diastolic, and mean arterial pressure in dogs weighing 8-11.5 kg.     

Variance of indirect blood pressure measurements and prevalence of hypertension in clinically normal dogs

In a series of 3 studies, indirect blood pressure measurements were obtained to define normal variance, identify hypertension, and estimate the prevalence of hypertension in apparently healthy dogs. In part 1, we measured values in 5 clinically normal dogs twice weekly for 5 weeks in a home setting. Mean +/- SD systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) was 150 +/- 16 and 86 +/- 13 mm of Hg, respectively. The DAP significantly (P less than 0.01) decreased with repeated measurements over the 5-week period. In part 2, we assessed the variation between blood pressures measured in a clinic vs those measured in the home. Within a 2-week period, measurements were obtained from 10 clinically normal dogs in a private veterinary clinic and again in their home. Significant differences were not observed between clinic and home measurements of SAP and DAP; however, heart rate was significantly (P less than 0.05) higher in the clinic. In part 3, SD about the SAP and DAP mean values were determined in 102 clinically normal dogs. Canine hypertensive status was determined, using statistical methods and data from 102 clinically normal dogs. Values of SAP greater than 202 mm of Hg and DAP greater than 116 mm of Hg were determined to be 2 SD beyond the mean and, therefore, were interpreted to be hypertensive. Approximately 10% of the 102 apparently healthy dogs measured in this study were considered hypertensive on the basis of these criteria. In addition, a border zone of suspected hypertension was estimated, using the mean + 1.282 SD. The SAP border zone was between 183 and 202 mm of Hg, whereas the DAP border zone was between 102 and 113 mm of Hg. Of the 102 dogs, 12 had values within these zones of suspected hypertension.     

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.     

Comparison of ultrasonic Doppler flow monitor,oscillometric, and direct arterial blood pressure measurements in ill dogs

Objective – To compare blood pressure measurements obtained via ultrasonic Doppler flow monitor (DOP) and 2 oscillometric noninvasive blood pressure monitors (CAR and PAS) to invasive blood pressure (IBP) in hospitalized, conscious dogs with a range of blood pressures. Design – Prospective clinical study. Setting – University teaching hospital. Animals – Eleven client‐owned dogs aged between 4 months and 11.5 years (median 6 y), and weighing between 5.8 and 37.5 kg (median 30.2 kg). Interventions – Blood pressure measurement. Measurements and Main Results – Three consecutive measurements of systolic, diastolic, and mean arterial pressure (MAP) were recorded for each of the 3 indirect devices (only systolic for DOP), along with concurrent IBP measurements. The data were categorized into 3 groups: hypotensive (direct MAP<80 mm Hg), normotensive (80 mm Hg≤direct MAP≥100 mm Hg), and hypertensive (direct MAP>100 mm Hg). Each indirect method was compared with the corresponding direct arterial pressure using the Bland‐Altman method. Within the hypotensive group, each indirect method overestimated the corresponding IBP. Within the normotensive group all indirect systolic measurements and the PAS diastolic measurements underestimated the corresponding IBP. The remaining indirect measurements overestimated the corresponding IBP. Within the hypertensive group, DOP and CAR systolic measurements underestimated the corresponding IBP, and the remaining indirect measurements overestimated the corresponding IBP. In hypertensive dogs oscillometric systolic measurements were more accurate than MAP. In hypotensive dogs MAP measurements were more accurate than systolic measurements. All indirect measurements were most accurate in hypertensive dogs. Conclusions – The noninvasive blood pressure monitors in our study did not meet the validation standards set in human medicine. However, CAR diastolic and MAP measurements within the normotensive group, CAR MAP measurements within the hypertensive group, and PAS diastolic measurements in all groups were close to these standards. All indirect measurements showed greater bias during hypotension. Precision was poorer for all indirect systolic measurements than for MAP.     

A comparison of direct and indirect (oscillometric) measurements of arterial blood pressure in anaesthetised dogs, using tail and limb cuffs

Oscillometric measurements of arterial blood pressure were compared with direct measurements in anaesthetised dogs being monitored during routine surgery. Readings were obtained with tail cuffs and limb cuffs and the reproducibility (precision) of the readings from various cuff sites was also compared in conscious dogs. Tail cuffs gave the best precision in conscious dogs and the closest correlation with direct measurements in anaesthetised dogs, especially for systolic pressure. The proximal hindlimb site gave results with a slightly lower precision.     

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.     

Central venous pressure and arterial blood pressure measurements.

Arterial blood pressure measurement and central venous pressure monitoring are important tools in the management of the critically ill pet. Central venous pressure is reflective of right atrial pressure and provides information concerning volume status. Arterial blood pressure is helpful in determining if perfusion to vital tissues is adequate. By providing more information with which to tailor fluid therapy and by prompt recognition of hypo- or hypertension, these monitoring tools are instrumental in the management of the critically ill pet.     

Non-invasive blood pressure measurement in dogs and cats

Bloodpressure measurements are of interest for todays veterinary practice. It can be used for screening of incoming patients, the emergency case, the intensive care patient and sedated animal. Furthermore, like in human medicine, blood pressure can be influenced by several diseases. The most reliable method of arterial blood pressure measurement is the direct or invasive method. Only the non-invasive methods doppler and oscillometric methods are used in veterinary medicine. The article describes the method of measurement, and provides a review of the literature. The oscillometric method especially in dogs. Both methods measure a lower bloodpressure if compared with an invasive method. The difference in bloodpressure is for the oscillometric method in cats greater then in dogs and appears to increase at higher blood pressures. Keeping these facts in focus, and if one is able to work in a quiet environment, repeat the measurements and maintain a critical attitude, blood pressure measurements can be performed in veterinary practice.     

Comparison of direct and Doppler arterial blood pressure measurements in rabbits during isoflurane anaesthesia

ObjectiveTo measure the level of agreement between Doppler measured (DOP) arterial blood pressure (ABP) in the forelimb and directly measured (DIR) auricular systolic ABP (SAP) and mean ABP (MAP) in isoflurane-anaesthetized rabbits.Study designProspective clinical study.AnimalsData were analysed from 17 of 24 healthy rabbits, weighing 1.3–2.8 kg.MethodsRabbits were anaesthetized for neutering using a standardized protocol. A 26G catheter placed in an auricular artery was connected via heparinised saline filled non-compliant tubing (regularly flushed) to a calibrated pressure transducer (zeroed level with the thoracic inlet) to obtain DIR ABP. A cuff was placed proximal to the carpus (approximately level with the thoracic inlet) and a Doppler transducer sited over the dorsal carpal branch of the radial artery to obtain DOP ABP. Simultaneous DIR and DOP ABP recordings were made every 5–10 minutes during anaesthesia. Agreement was assessed as described by Bland JM &; Altman (2007).ResultsMean ± SD cuff width: limb circumference ratio was 0.50 ± 0.04. Mean between-method differences ± SD, DIR SAP- DOP and DIR MAP- DOP, were +1 ± 8 and ?13 ± 8 mmHg respectively. The 95% limits of agreement between DIR SAP and DOP and between DIR MAP and DOP were ?14 to +17 and ?28 to +2 mmHg respectively. Differences between DIR SAP and DOP were ≤10 mmHg 85% of the time. Defining hypotension as either DIR SAP < 80 mmHg or DIR MAP < 60 mmHg, and taking DOP ABP of <80 mmHg to indicate hypotension, sensitivity and specificity were 92% and 67% respectively.ConclusionsGood agreement was found between DIR SAP and DOP. Doppler measurements below 80 mmHg are a reliable indicator of arterial hypotension.Clinical relevanceDOP is acceptable for monitoring ABP in isoflurane-anaesthetized rabbits and is useful for detection of hypotension.     

Comparison of arterial blood pressure measurements obtained invasively or oscillometrically using a Datex S/5 Compact monitor in anaesthetised adult horses

Objective

To assess agreement between noninvasive blood pressure (NIBP) oscillometrically-derived values from a multiparameter monitor (Datex Ohmeda S/5 Compact) with those obtained by invasive blood pressure (IBP) measurement in anaesthetised horses undergoing elective surgery.

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.     

Accuracy of indirect measurement of blood pressure in neonatal foals

The objectives of this study were to assess, in anesthetized neonatal foals, the accuracy of 2 automated indirect oscillometric monitors for measurement of mean arterial pressure (MAP), to determine the optimal site of cuff placement for MAP monitoring, and to determine the relationship between arterial blood pressure and cardiac output. Ten neonatal foals were anesthetized and instrumented with a catheter in the metatarsal artery for direct MAP monitoring and measurement of cardiac output by lithium dilution. Concurrent MAP measurements were obtained with Cardell and Dinamap oscillometric monitors with cuffs placed at 3 different sites (coccygeal, metatarsal, and median arteries). Blood pressure was manipulated by varying the depth of anesthesia and by administration of dobutamine or phenylephrine. A statistically significant (P = .025) interaction was found between the type of monitor and cuff placement site. With the Cardell monitor, placement of the cuff over the coccygeal artery resulted in a significantly lower bias than placement over the median or dorsal metatarsal artery (P < .0001 and P = .0149, respectively). No significant difference in bias was found with cuff placement site when using the Dinamap monitor. The correlation coefficient (r) between MAP and cardiac output was 0.47. Indirect oscillometry with a cuff placed over the coccygeal artery or dorsal metatarsal artery is an acceptable method for measuring MAP in foals. Blood pressure does not correlate well with cardiac output in anesthetized foals.