Direct Arterial Blood Pressure Measurements Research Articles

Use of vasopressors for treatment of vasodilatory hypotension in dogs and cats by Diplomates of the American College of Veterinary Emergency and Critical Care.

To identify the most common practices of Diplomates of the American College of Veterinary Emergency and Critical Care (DACVECCs) as they relate to the recognition and treatment of hypotension in dogs and cats, particularly concerning the use of vasopressors in vasodilatory shock states. A survey regarding vasopressor use was sent to all active DACVECCs using the Veterinary Information Network. Questions focused on respondent characteristics, method of recognition of hypotension, triggers for initiation of vasopressor therapy, first- and second-line vasopressor choice, and methods of determining response to therapy. A total of 734 DACVECCs were invited to participate, and 203 Diplomates (27.7%) completed the survey. For both dogs and cats, the most common first-line vasopressor was norepinephrine (87.9% in dogs and 83.1% in cats). The most common second-choice vasopressor was vasopressin (44.2% in dogs and 39.0% in cats). Cutoff values for initiating vasopressor therapy varied between species and modality used for blood pressure measurement. In general, most DACVECCs chose to initiate vasopressor therapy at a Doppler blood pressure <90mmHg or a mean arterial pressure of <60 or <65mmHg when using oscillometric or direct arterial blood pressure measurements in dogs and cats. Most DACVECCs adhere to published human guidelines when choosing a first-line vasopressor. However, there is significant variability in blood pressure measurement technique, cutoffs for initiation of vasopressor use, and choice of second-line vasopressors.

Short‐term Western Diet Induces Cardiometabolic Syndrome in Female Rats is Associated with Increased Cardiovascular Protein Lysine Acetylation.

The western diet (WD), which is rich in fat, carbohydrates, and refined sugars, is a major contributor to the global epidemic of metabolic syndrome in our modern society. Despite the well‐documented cardioprotection exhibited by the pre‐menopausal female population, studies have indicated that certain stressors may abolish this cardiovascular protection. Studies on the impact of the WD on the cardiometabolic profile of female cohorts remains limited. Lysine acetylation, a reversible posttranslational modification of histone and non‐histone proteins, has been closely associated with metabolic disorders. Based on these factors, we hypothesized that short‐term exposure to the WD alters cardiometabolic parameters in premenopausal rats and alters levels of lysine acetylation in the cardiovascular tissues. Adult female Wistar rats were randomized in two groups: Control Group (n=8) was assigned a regular chow diet and WD Group (n=12) received WD (40% fat, 43% carbohydrates, and 17% protein) for 17 weeks. Results showed that WD group exhibited increased body weight (376 ± 49 vs 305 ± 41g, p&lt;0.05), periabdominal fat content (30 ±11 vs 11 ±2g, p&lt;0.01), % body fat (8.1 ±1.0 vs 3.6 ±0.4%, p&lt;0.01), and serum triglyceride levels (56 ± 13 vs 25 ± 4 mg/dl, p&lt;0.01) compared to controls. Although the WD group exhibited significant increases in glucose intolerance (AUC: 17068.5 ± 730 vs. 13787.67± 814 a.u, p&lt;0.01) and insulin resistance (HOMA‐IR: 5.75 ± 0.9 vs. 3.25 ± 0.62 control, p&lt;0.05), no differences in fasting blood glucose and hemoglobin A1C were found. Using direct arterial blood pressure measurements via carotid artery catheterization, we observed increased systolic blood pressure (146.19 ±9.4 vs 126.22 ± 9.8 mmHg controls, p&lt;0.001), which is contradictory with previous studies. Our vascular reactivity studies revealed that short‐term WD markedly impaired endothelial‐dependent relaxation. Additionally, using DHE staining we found that aortas from the WD group exhibited augmented levels of oxidative stress (3.1‐fold increase vs. control, p&lt;0.001). Strikingly, levels of global lysine acetylation were markedly elevated in the aortas (2.2‐fold increase vs. control, p&lt;0.01) and heart (1.4‐fold increase vs. control, p&lt;0.05) of WD group. Levels of acetyltransferase PCAF were significantly upregulated in the aortas (2.2‐fold increase vs. control, p&lt;0.05). Interestingly, PCAF and deacetylase HDAC9 expression was diminished in hearts from WD group (30% reduction vs. control, p&lt;0.05) and (85% reduction vs. control, p&lt;0.05), respectively. Besides these cardiovascular alterations, the WD also led to the development of non‐alcoholic fatty liver disease (NAFLD) and robust increases in hepatic global lysine acetylation (3.0‐fold increase vs. control, p&lt;0.001). Taken together, our results demonstrated that, even under short‐term exposure, the WD negatively affects the metabolic and cardiovascular parameters of female rats and it is associated with elevated levels of global lysine acetylation in cardiometabolic tissues. This study will be further conducted to identify the specific proteins acetylated in blood vessels and heart from female population under WD regimes.Support or Funding InformationIn‐house Grant NYIT to MACSThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Non-invasive blood pressure measurement in ferrets (Mustela putorius furo) using high definition oscillometry

This study was conducted to validate the use of high definition oscillometry (HDO) for non-invasive blood pressure (NIBP) measurements in ferrets and to establish reference ranges for NIBP in minimally sedated, healthy, young adult ferrets (<4years of age). The bias, limits of agreement and correlation for HDO compared to direct arterial blood pressure (DABP) measurement were established in 14 anaesthetised ferrets. Measurements were performed at the forelimb, hind limb and tail under hypo- (<110mmHg), normo- (110–170mmHg) and hypertensive (>170mmHg) conditions. Although HDO correlated well with DABP (r>0.90), it showed significant proportional bias, whereby HDO generally underestimated DABP with hyper- and normotensive conditions, and overestimated DABP with hypotensive conditions. Measurements obtained from the hind limb showed higher bias than those obtained from the tail or forelimb (P<0.001). Based on the above, and for practical reasons, the tail was selected as the preferred site of cuff placement in ferrets. Subsequently, a cross-over study was performed in 10 ferrets to establish the minimum dose of butorphanol and midazolam needed to successfully obtain NIBP in 100% of cases. Using this dose (0.2mg/kg IM, each), reference intervals for NIBP from 63 healthy, young adult ferrets were established at 95–155mmHg (systolic), 69–109mmHg (mean) and 51–87mmHg (diastolic) arterial pressures.

Validity and reliability of Doppler ultrasonography and direct arterial blood pressure measurements in anaesthetized dogs weighing less than 5 kg

ObjectiveTo assess the validity and reliability of Doppler ultrasonography (DOP) as compared with invasive arterial blood pressure measurements in anaesthetized dogs weighing less than 5 kg. Study designControlled, prospective, clinical study. AnimalsA total of 41 privately owned dogs weighing less than 5 kg. MethodsThe dogs were anaesthetized, and an intra-arterial catheter was placed aseptically in the dorsal pedal artery of the pelvic limb to perform invasive blood pressure (IBP) measurement. The contralateral metatarsal surface of the foot was clipped in order to perform DOP. Both techniques were used to record blood pressure measurements every 5 minutes during surgical procedures. The blood pressure measurements were categorized into two groups: hypotensive [mean arterial pressure (MAP) < 60 mmHg] and normotensive (MAP between 60 and 120 mmHg). A linear mixed model was used to compare the DOP and IBP values. The results were evaluated according to the requirements of the American College of Veterinary Internal Medicine (ACVIM) guidelines for the validation of devices. ResultsDOP provided higher values compared to the systolic arterial blood pressure (SAP) and MAP of IBP measurements. The closest agreement between the two techniques was found for SAP; the bias was 8.8, and limits of agreement (LOA) were –32.9 and 50.4. Similar results were observed when the IBP technique was categorized. The closest agreement was for SAP in animals categorized as normotensive; the bias was 8.2, and LOAs were –32.8 and 49.2. The level of agreement between DOP and IBP did not meet the ACVIM recommendations. Conclusions and clinical relevanceOur results suggest there is poor agreement between DOP and IBP measurements in anaesthetized dogs weighing less than 5 kg. Hence, the use of DOP in these animals could be misleading.

Agreement of high definition oscillometry with direct arterial blood pressure measurement at different blood pressure ranges in horses under general anaesthesia

ObjectiveTo determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia. Study designExperimental study. AnimalsSeven healthy warmblood horses, aged 3–11 years, weighing 470–565 kg. MethodsMeasurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg−1 minute−1) over ten minutes followed by norepinephrine (0.1 mg kg−1 IV) and low pressures by increasing the inspired fraction of isoflurane and administration of nitroglycerine (0.05 mg kg−1 IV). For analysis three pressure levels were determined: high (MAP>110 mmHg), normal (60 mmHg<MAP<110 mmHg) and low (MAP< 60 mmHg). Bland-Altman analysis was used for comparison between non-invasive and invasive measurements. ResultsA total of 245 paired measurements of systolic (SAP), mean (MAP) and diastolic (DAP) pressures were obtained. The HDO device underestimated blood pressure at hypertensive and normotensive levels and overestimated blood pressure at hypotensive levels. Best agreement was obtained for SAP and MAP within normotensive limits. At normotension, bias ± standard deviation for SAP, MAP and DAP were 0.1 ± 19.4 mmHg, 0.5 ± 14.0, 4.7 ± 15.6, respectively. At high pressure levels bias and SD were 26.1 ± 37.3 (SAP), 4.2 ± 19.4 (MAP), 1.5 ± 16.8 (DAP) and at low pressures -20.0 ± 20.9 (SAP), -11.4 ± 19.6 (MAP), -4.7 ± 20.1 (DAP), with HDO measurements at a MAP <50 mmHg often failing. Conclusion and clinical relevanceGood agreement with invasive arterial blood pressures was obtained with HDO at normotensive levels in horses. At high and low pressure ranges HDO was unreliable. Therefore, if haemodynamic instability is expected, invasive measurement remains preferable.

Noninvasive Hemodynamic Monitoring Devices

Noninvasive Hemodynamic Monitoring Devices

The Cardiovascular Effects of Sevoflurane and Isoflurane After Premedication of Healthy Dogs Undergoing Elective Surgery

Sevoflurane and isoflurane are commonly used in veterinary anesthesia. The objective of this prospective, randomized, open-label clinical study was to compare the cardiovascular effects of sevoflurane and isoflurane via direct arterial blood pressure measurements and the lithium dilution cardiac output (LDCO) on premedicated healthy dogs undergoing elective tibial plateau leveling osteotomy (TPLO). Nineteen client-owned dogs were included. All dogs were premedicated with hydromorphone (0.05 mg/kg IV and glycopyrrolate 0.01 mg/kg subcutaneously). Ten dogs were anesthetized with sevoflurane and nine dogs were anesthetized with isoflurane. Eighteen dogs were instrumented with a dorsal pedal arterial catheter, and one dog had a femoral arterial catheter. All dogs had continuous, direct systolic (SAP), diastolic (DAP), and mean arterial (MAP) blood pressure readings as well as heart rate (HR), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI), stroke volume variation (SVV), and pulse pressure variation (PPV) recorded q 5 min during the surgical procedure. There was no significant statistical difference in all parameters between the sevoflurane and isoflurane treatment groups. Both sevoflurane and isoflurane inhalant anesthetics appear to have similar hemodynamic effects when used as part of a multimodal anesthetic protocol in premedicated healthy dogs undergoing an elective surgical procedure.

Effect of high zinc dose on haematological, lipids and protein patterns in dromedary camel- revised

Surgical lateralisation of the left carotid artery (LLCA) is frequently used to allow easy access to direct (invasive) arterial blood pressure and blood gas measurement in experimental settings. An experimental study was conducted in 15 dromedary camels of 2–12; average 4.9 ± 2.6 years and weighing 250–480, average 375.4 ± 74.3 kg. Animals were divided into 3 groups receiving one of 3 different surgical lateralization techniques. In group 1, the carotid was exposed over a continuous suture bed and covered with a wide skin flap. In group 2, a tunnel was made at the ventral part of skin flap to pass and cover the carotid artery. In Group 3, the carotid artery was loosely inserted subcutaneously between the sternocephalic and intertransverse muscles and held through a loop of non-absorbable suture material protruding with its free ends over the incision line to allow easier localisation and gentle grasping of the artery during experiment. Animals were observed for 7 days and any abnormalities noted. Base echocardiography was performed before collection of samples. Arterial and venous samples were collected twice from each group. Five animals died at variable period after the operations. Thrombosis in 4 animals (2 from group I and 2 from group II) was noted, and Post-mortem angiographaphy in one camel showed cerebral ischaemia.

High-definition oscillometry and direct arterial blood pressure measurement

High-definition oscillometry and direct arterial blood pressure measurement

Short- and long-term effects of a maternal low-protein diet on ventilation, O2/CO2chemoreception and arterial blood pressure in male rat offspring

Maternal undernutrition increases the risk of adult arterial hypertension. The present study investigated the short- and long-term effects of a maternal low-protein diet on respiratory rhythm, O₂/CO₂ chemosensitivity and arterial blood pressure (ABP) of the offspring. Male Wistar rats were divided into two groups according to their mothers' diets during gestation and lactation: control (NP, 17% of casein) and low-protein (LP, 8% of casein) groups. Direct measurements of ABP, respiratory frequency (RF), tidal volume (V T) and ventilation (VE), as well as hypercapnia (7% CO₂) and hypoxia (7% O₂) evoked respiratory responses were recorded from the awake male offspring at the 30th and 90th days of life. Blood samples were collected for the analyses of protein, creatinine and urea concentrations. The LP offspring had impaired body weight and length throughout the experiment. At 30 d of age, the LP rats showed a reduction in the concentrations of total serum protein (approximately 24%). ABP in the LP rats was similar to that in the NP rats at 30 d of age, but it was 20% higher at 90 d of age. With respect to ventilatory parameters, the LP rats showed enhanced RF (approximately 34%) and VE (approximately 34%) at 30 d of age, which was associated with increased ventilatory responses to hypercapnia (approximately 21% in VE) and hypoxia (approximately 82% in VE). At 90 d of age, the VE values and CO₂/O₂ chemosensitivity of the LP rats were restored to the control range, but the RF values remained elevated. The present data show that a perinatal LP diet alters respiratory rhythm and O₂/CO₂ chemosensitivity at early ages, which may be a predisposing factor for increased ABP at adulthood.

A clinical comparison between a non–invasive blood pressure monitor using high definition oscillometry (Memodiagnostic MD 15/90 Pro) and invasive arterial blood pressure measurement in anaesthetized dogs

ObjectiveTo compare high definition oscillometry (HDO) to invasive blood pressure measurement in anaesthetized dogs. Study designProspective, clinical trial. AnimalsFifty dogs weighing 1.95–79 kg (mean 23.5 kg). Materials and methodsAnaesthetic and peri–anaesthetic management was chosen according to each dog's physical status and anaesthetist's preference. Direct arterial blood pressure measurements were performed using a catheter placed in the dorsal pedal artery and an electronic pressure transducer connected to a multiparameter monitor. Non–invasive blood pressure measurements were performed using an appropriately sized cuff placed around the tail base. Comparisons between the two methods were made using Bland and Altman plots. The data are reported as mean bias (lower, upper limits of agreement). Further analysis was performed after separating the data into the following categories based on invasive mean arterial blood pressure (MAP): high (MAP > 100 mmHg), medium (70 mmHg < MAP < 100 mmHg) and low (MAP < 70 mmHg) blood pressure (BP). The two methods were compared as used clinically. ResultsEight hundred measurement pairs for invasive and HDO BP readings were compared. Overall, the HDO measured lower values for SAP and DAP but higher for MAP than the invasive method. The lowest bias (upper, lower limits of agreement) were obtained for MAP, −1 (−22, 19) mmHg. The biggest discrepancy between the methods was reflected by a large bias (limits of agreement) 5 (−34, 45) mmHg, was for SAP. The results for DAP were between those for SAP and MAP with a bias (limits of agreement) of 3 (−20, 27) mmHg. When the values were separated into the pressure range categories the HDO measured higher in the high, medium and low BP groups, with the exception of SAP in the low BP group. ConclusionsWhen considering the mean bias, the accuracy of HDO compared well with direct arterial blood pressure, but the precision was poor, as determined by wide limits of agreement. Clinical relevanceUsing trends and serial measurements rather than a single measurement for clinical decision making is recommended with both methods, when used as reported here.

Intraoperative Hypotension and Patient Outcome

Intraoperative Hypotension and Patient Outcome

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

This study was performed to evaluate three different noninvasive blood pressure measurement methods (NIBP) in comparison with direct blood pressure measurements in anesthetized dogs. Ten normal healthy Beagle dogs (mean age; 3.7 ± 1.01 yrs, mean body weight 10.2 ± 1.15 kg) were enrolled in this study. The BP was measured by three different methods, i.e., Doppler (DOP), oscillometric and high density oscillometric (HDO), simultaneously for 5 times in each subject under anesthesia at three different locations (right, left front legs and tail). The blood pressure value measured by Doppler method was the most close to the value measured by the direct method. Although the accuracy and consistency of the BP measured by 3 different non-invasive methods were differed by the method, all methods except conventional oscillometric method were acceptable for monitoring systolic blood pressure in anesthetic dogs and the inter-measurement variations in DOP and HDO was minimal enough not to affect the consistency of test result.

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

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. Prospective clinical study. University teaching hospital. 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). Blood pressure measurement. 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<or=direct MAP>or=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. 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.

Underwater study of arterial blood pressure in breath-hold divers

Knowledge regarding arterial blood pressure (ABP) values during breath-hold diving is scanty. It derives from a few reports of measurements performed at the water's surface, showing slight or no increase in ABP, and from a single study of two simulated deep breath-hold dives in a hyperbaric chamber. Simulated dives showed an increase in ABP to values considered life threatening by standard clinical criteria. For the first time, using a novel noninvasive subaquatic sphygmomanometer, we successfully measured ABP in 10 healthy elite breath-hold divers at a depth of 10 m of freshwater (mfw). ABP was measured in dry conditions, at the surface (head-out immersion), and twice at a depth of 10 mfw. Underwater measurements of ABP were obtained in all subjects. Each measurement lasted 50-60 s and was accomplished without any complications or diver discomfort. In the 10 subjects as a whole, mean ABP values were 124/93 mmHg at the surface and 123/94 mmHg at a depth of 10 mfw. No significant statistical differences were found when blood pressure measurements at the water surface were compared with breath-hold diving conditions at a depth of 10 mfw. No systolic blood pressure values >140 mmHg or diastolic blood pressure values >115 mmHg were recorded. In conclusion, direct measurements of ABP during apnea diving showed no or only mild increases in ABP. However, our results cannot be extended over environmental conditions different from those of the present study.

Agreement between direct and indirect blood pressure measurements obtained from anesthetized Hispaniolan Amazon parrots

To determine the level of agreement between direct and indirect blood pressure measurements obtained from healthy Hispaniolan Amazon parrots (Amazona ventralis) anesthetized with isoflurane. Validation study. 16 healthy adult Hispaniolan Amazon parrots. Parrots were anesthetized, and a 26-gauge, 19-mm catheter was placed percutaneously in the superficial ulnar artery for direct measurement of systolic, mean, and diastolic arterial pressures. Indirect blood pressure measurements were obtained with a Doppler ultrasonic flow detector and an oscillometric unit. The Bland-Altman method was used to compare direct and indirect blood pressure values. There was substantial disagreement between direct systolic arterial blood pressure and indirect blood pressure measurements obtained with the Doppler detector from the wing (bias, 24 mm Hg; limits of agreement, -37 to 85 mm Hg) and from the leg (bias, 14 mm Hg; limits of agreement, -14 to 42 mm Hg). Attempts to obtain indirect blood pressure measurements with the oscillometric unit were unsuccessful. Results suggested that there was substantial disagreement between indirect blood pressure measurements obtained with a Doppler ultrasonic flow detector in anesthetized Hispaniolan Amazon parrots and directly measured systolic arterial blood pressure.

Response of cats to familiar and unfamiliar human contact using continuous direct arterial blood pressure measurement

Continuous direct measurement of feline arterial blood pressure (ABP) was carried out via a modified method with percutaneous, ultrasound guided catheterization of the common carotid artery. In 21 healthy, conscious cats the ABP was measured during rest, alertness and activity. Furthermore, the ABP response to being petted by familiar and unfamiliar persons was assessed. Linear mixed modelling revealed that the mean blood pressure (MBP) in resting cats (114.6 mmHg) was lower ( P < 0.001) than in alert cats (122.7 mmHg), which was lower ( P < 0.001) than that of active cats (136.8 mmHg). The MBP during petting by a familiar person (144.7 mmHg) tended to be higher ( P = 0.065) than that during petting by an unfamiliar person (139.4 mmHg). The MBP of active cats was lower ( P = 0.003) than MBP of cats petted by a familiar person, but not different from MBP of cats petted by an unfamiliar person. The MBP returned to resting values between 16 and 20 min after the familiar person had left, whereas resting values were reached between 11 and 15 min after the unfamiliar person had left. The complications of the described method were limited considering the potential risks of continuous direct ABP measurement. In conclusion, the described technique enables accurate measurement of feline ABP, which is influenced by the cat’s activity level and the familiarity of persons.

Arterial Versus Plethysmographic Dynamic Indices to Test Responsiveness for Testing Fluid Administration in Hypotensive Patients: A Clinical Trial

In the present study, we compared indices of respiratory-induced variation obtained from direct arterial blood pressure measurement with analogous indices obtained from the plethysmogram measured by the pulse oximeter to assess the value of these indices for predicting the cardiac output increase in response to a fluid challenge. Thirty-two fluid challenges were performed in 22 hypotensive patients who were also monitored with a pulmonary artery catheter. Hemodynamic and plethysmographic data were collected before and after intravascular volume expansion. Patients were classified as nonresponders if their cardiac index did not increase by 15% from baseline. Nonresponding patients had both lower arterial pulse variation ([10 +/- 4]% vs [19 +/- 13]%, P = 0.020) and lower plethysmographic pulse variation ([12 +/- 7]% vs [21 +/- 14]%, P = 0.034) when compared with responders. Fluid responsiveness was similarly predicted by arterial and plethysmographic pulse variations (area under ROC curve 0.74 vs 0.72, respectively, P = 0.90) and by arterial and plethysmographic systolic variation (area under ROC curve 0.64 vs 0.72, respectively, P = 0.50). Nonresponders were identified by changes in pulse variation both on arterial and plethysmographic waveform (area under ROC curve 0.80 vs 0.87, respectively, P = 0.40) and by changes in arterial and plethysmographic systolic variations (area under ROC curve 0.84 vs 0.80, respectively, P = 0.76). In the population studied, plethysmographic dynamic indices of respiratory-induced variation were just as useful for predicting fluid responsiveness as the analogous indices derived from direct arterial blood pressure measurement. These plethysmographic indices could provide a noninvasive tool for predicting the cardiac output increase by administering fluid.

Accuracy of an oscillometric blood pressure monitor during phenylephrine-induced hypertension in dogs

To examine the agreement between direct arterial blood pressure measurements obtained from 2 arteries and indirect blood pressure measurements obtained with an oscillometric blood pressure monitor (OBPM) during normotension and phenylephrine-induced hypertension in dogs. 16 male Beagles. In anesthetized dogs, arterial catheters were placed in the lingual and dorsal pedal arteries for measurement of arterial blood pressure. A blood pressure cuff was placed on either the dog's fore- or hind limb and connected to an OBPM. Systolic, diastolic, and mean arterial blood pressures (SAP, DAP, and MAP, respectively) were recorded from both arteries and the OBPM every 5 minutes for 30 minutes (baseline), during a 30-minute period in which dogs received a phenylephrine infusion IV to induce hypertension, and for 30 minutes after discontinuation of the infusion. Mean differences in blood pressure values and confidence intervals were calculated to compare the indirect and direct measurement techniques. In dogs, oscillometry underestimated SAP during normotension, and the difference between oscillometric and direct measurements increased during hypertension. Oscillometry underestimated DAP, but the difference between oscillometric and direct measurements decreased during hypertension. There was close agreement among techniques for MAP determinations. Biases between direct measurements and OPBM blood pressure values measured from dogs' forelimbs or hind limbs were not significantly different. In normotensive dogs, oscillometric measurements of MAP and SAP agreed more closely with direct arterial pressure measurements than oscillometric estimates of DAP. Oscillometric measurement of MAP was accurate during both normotension and hypertension in dogs.