Oscillometric Arterial Blood Pressure Research Articles

IMMOBILIZATION OF BLACK HOWLER MONKEYS (ALOUATTA PIGRA) USING BUTORPHANOL, AZAPERONE, MEDETOMIDINE IS SAFE AND EFFECTIVE FOR NONINVASIVE PROCEDURES.

Administration of butorphanol, azaperone, and medetomidine (BAM) for immobilization of black howler monkeys (Alouatta pigra) has not been previously reported. In this observational study, 0.02 ml/kg of compounded BAM (butorphanol 27.3 mg/ml, azaperone 9.1 mg/ml, medetomidine 10.9 mg/ml) was administered IM in 10 captive black howler monkeys. Time to immobilization was recorded, an arterial blood gas performed, and at 5-min intervals, HR, RR, oscillometric arterial blood pressure, SPO2, and rectal temperature were measured. Naltrexone and atipamezole were administered IM at procedure completion and recovery times were recorded. If invasive procedures such as surgery were necessary and additional drugs needed, further data from that individual was removed from data analysis. Final BAM dosages were 0.55 ± 0.12 mg/kg butorphanol, 0.19 ± 0.04 mg/kg azaperone, and 0.22 ± 0.05 mg/kg medetomidine. Nine of 10 monkeys achieved sedation allowing for physical exam, venipuncture, and tuberculin skin testing within 4 ± 2 min. No monkeys reached a plane of immobilization allowing for intubation. Physiologic variables were acceptable for this species. Hypoxemia (SPO2 < 95%) was observed in three monkeys via pulse oximetry, and normoxemia was observed on arterial blood gas. Recovery was smooth and rapid. Therefore, BAM is a viable option for noninvasive procedures or as a premedication prior to induction of anesthesia in black howler monkeys.

Oscillometric arterial blood pressure in haemodynamically stable neonates in the first 2 weeks of life

BackgroundWe aimed to provide data on the normal blood pressure of haemodynamically stable neonates. Our study uses retrospective, real-life oscillometric blood pressure measurement values to determine the expected blood pressure in different gestational age, chronological age and birth weight groups. We also investigated the effect of antenatal steroid on neonatal blood pressure.MethodsOur retrospective study (2019–2021) was carried out in the Neonatal Intensive Care Unit of the University of Szeged, Hungary. We involved 629 haemodynamically stable patients and analysed 134,938 blood pressure values. Data were collected from electronic hospital records of IntelliSpace Critical Care Anesthesia by Phillips. We used the PDAnalyser program for data handling and the IBM SPSS program for statistical analysis.ResultsWe found a significant difference between the blood pressure of each gestational age group in the first 14 days of life. The systolic, diastolic and mean blood pressure rise are steeper in the preterm group than in the term group in the first 3 days of life. No significant blood pressure differences were found between the group with a complete antenatal steroid course and those who received incomplete steroid prophylaxis or did not receive antenatal steroids.ConclusionWe determined the average blood pressure of stable neonates and obtained normative data by percentiles. Our study provides additional data on how blood pressure varies with gestational age and birth weight.Graphical abstractA higher resolution version of the Graphical abstract is available as Supplementary information

Effect of intravenous fentanyl on cough reflex and quality of endotracheal intubation in cats

ObjectiveTo assess the effects of intravenous (IV) fentanyl on cough reflex and quality of endotracheal intubation (ETI) in cats. Study designRandomized, blinded, negative controlled clinical trial. AnimalsA total of 30 client-owned cats undergoing general anaesthesia for diagnostic or surgical procedures. MethodsCats were sedated with dexmedetomidine (2 μg kg–1 IV), and 5 minutes later either fentanyl (3 μg kg–1, group F) or saline (group C) was administered IV. After alfaxalone (1.5 mg kg–1 IV) administration and 2% lidocaine application to the larynx, ETI was attempted. If unsuccessful, alfaxalone (1 mg kg–1 IV) was administered and ETI re-attempted. This process was repeated until successful ETI. Sedation scores, total number of ETI attempts, cough reflex, laryngeal response and quality of ETI were scored. Postinduction apnoea was recorded. Heart rate (HR) was continuously recorded and oscillometric arterial blood pressure (ABP) was measured every minute. Changes (Δ) in HR and ABP between pre-intubation and intubation were calculated. Groups were compared using univariate analysis. Statistical significance was set as p < 0.05. ResultsThe median and 95% confidence interval of alfaxalone dose was 1.5 (1.5–1.5) and 2.5 (1.5–2.5) mg kg–1 in groups F and C, respectively (p = 0.001). The cough reflex was 2.10 (1.10–4.41) times more likely to occur in group C. The overall quality of ETI was superior in group F (p = 0.001), with lower laryngeal response to ETI (p < 0.0001) and ETI attempts (p = 0.045). No differences in HR, ABP and postinduction apnoea were found. Conclusions and clinical relevanceIn cats sedated with dexmedetomidine, fentanyl could be considered to reduce the alfaxalone induction dose, cough reflex and laryngeal response to ETI and to improve the overall quality of ETI.

Agreement between invasive and oscillometric arterial blood pressure measurement using a high-definition oscillometric device in normotensive New Zealand White rabbits using two different anaesthetic protocols

ObjectiveTo use American College of Veterinary Internal Medicine (ACVIM) criteria to evaluate a high-definition oscillometric (HDO) blood pressure monitoring device versus invasive blood pressure (IBP) measurement in normotensive rabbits anaesthetized with two different anaesthetic protocols. Study designProspective experimental study. AnimalsA group of 20 healthy adult New Zealand White rabbits weighing 4.36 ± 0.37 kg (mean ± standard deviation). Materials and methodsRabbits were premedicated with butorphanol 0.5 mg kg–1 and midazolam 0.5 mg kg–1 subcutaneously (SC, group BMA) or ketamine 25 mg kg–1 and medetomidine 0.4 mg kg–1 SC (group KM). Anaesthesia was induced with alfaxalone administered intravenously (group BMA) or isoflurane by face mask (group KM) and maintained with isoflurane in oxygen. IBP was measured from the central auricular artery. The cuff for the HDO monitor was placed distal to the left elbow and distal to the left tarsus. Agreement between invasive and HDO measurements was evaluated using Bland–Altman method. ResultsIn group KM there was better agreement between the HDO device and IBP when the cuff was placed on the thoracic limb, with 100% and 91% of the readings for mean (MAP) and diastolic arterial pressure (DAP), respectively, within 10 mmHg of the IBP measurements. The agreement, although worse, also met the ACVIM criteria for systolic arterial pressure (SAP; 53% of the readings within 10 mmHg). In group BMA, the device met the criteria with the cuff on the thoracic limb only, and only for MAP and DAP (73% and 75% of the measurements within 10 mmHg of the IBP, respectively) but not for SAP (12%). Conclusion and clinical relevanceThe HDO device met most of the ACVIM criteria for noninvasive blood pressure measurement in anaesthetized rabbits, specifically when the cuff was placed distal to the elbow and the anaesthetic protocol included ketamine and medetomidine.

Agreement between invasive and oscillometric arterial blood pressure measurements using the LifeWindow multiparameter monitor and two cuff sizes in anesthetized adult horses

ObjectiveTo assess agreement between oscillometric noninvasive blood pressure (NIBP) measurements using LifeWindow monitors (LW9xVet and LW6000V) and invasive blood pressure (IBP). To assess the agreement of NIBP readings using a ratio of cuff width to mid-cannon circumference of 25% and 40%. Study designProspective, randomized clinical study. AnimalsA total of 43 adult horses undergoing general anesthesia in dorsal recumbency for different procedures. MethodsAnesthetic protocols varied according to clinician preference. IBP measurement was achieved after cannulation of the facial artery and connection to an appropriately positioned transducer connected to one of two LifeWindow multiparameter monitors (models: LW6000V and LW9xVet). Accuracy of monitors was checked daily using a mercury manometer. For each horse, NIBP was measured with two cuff widths (corresponding to 25% or 40% of mid-cannon bone circumference), both connected to the same monitor, and six paired IBP/NIBP readings were recorded (at least 3 minutes between readings). NIBP values were corrected to the relative level of the xiphoid process. A Bland–Altman analysis for repeated measures was used to assess bias (NIBP–IBP) and limits of agreement (LOAs). ResultsThe 40% cuff width systolic arterial pressure [SAP; bias 7.9 mmHg, LOA –26.6 to 42.3; mean arterial pressure (MAP): bias 4.9 mmHg, LOA –28.2 to 38.0; diastolic arterial pressure (DAP): bias 4.2 mmHg, LOA –31.4 to 39.7)] performed better than the 25% cuff width (SAP: bias 26.4 mmHg, LOA –21.0 to 73.9; MAP: bias 15.7 mmHg, LOA –23.8 to 55.2; DAP: bias 10.9 mmHg, LOA –33.2 to 54.9). Conclusions and clinical relevanceUsing the LifeWindow multiparameter monitor in anesthetized horses, the 40% cuff width provided better agreement with IBP; however, both cuff sizes and both monitor models failed to meet American College of Veterinary Internal Medicine Consensus Statement Guidelines.

Monitoring Personalized Trait Using Oscillometric Arterial Blood Pressure Measurements

The blood pressure patterns obtained from a linearly or stepwise deflating cuff exhibit personalized traits, such as fairly uniform peak patterns and regular beat geometry; it can support the diagnosis and monitoring of hypertensive patients with reduced sensitivity to fluctuations in Blood Pressure (BP) over time. Monitoring of personalized trait in Oscillometric Arterial Blood Pressure Measurements (OABPM) uses the Linear Discriminant Analysis (LDA) algorithm. The representation of personalized traits with features from the oscillometric waveforms using LDA algorithm includes four phases. Data collection consists of blood pressure data using auscultatory measurements and pressure oscillations data obtained from the oscillometric method. Preprocessing involves the normalization of various sized oscillometric waveforms to a uniform size. Feature extraction involves the use of features from oscillometric amplitudes, and trait identification involves the use of the LDA algorithm. In this paper, it presents a novel OABPM‐based blood pressure monitoring system that can monitor personalized blood pressure pattern. Our approach can reduce sensitivity to fluctuations in blood pressure with the features extracted from the whole area in oscillometric arterial blood pressure measurement. Therefore this technique offers reliable blood pressure patterns. This study provides a cornerstone for the diagnosis and management of hypertension in the foreseeable future.

Two doses of dexmedetomidine in combination with buprenorphine for premedication in dogs; a comparison with acepromazine and buprenorphine

ObjectiveTo assess as premedicants, the sedative, cardiorespiratory and propofol-sparing effects in dogs of dexmedetomidine and buprenorphine compared to acepromazine and buprenorphine. Study designProspective, randomised, blinded clinical study AnimalsSixty healthy dogs (ASA grades I/II). Mean (SD) body mass 28.0 ± 9.1 kg, and mean age 3.4 ± 2.3 years. MethodsDogs were allocated randomly to receive 15 μg kg−1 buprenorphine combined with either 30 μg kg−1 acepromazine (group 1), 62.5 μg m−2 dexmedetomidine (group 2), or 125 μg m−2 dexmedetomidine (group 3) intramuscularly. After 30 minutes, anaesthesia was induced using a propofol target controlled infusion. Heart rate, respiratory rate, and oscillometric arterial blood pressure were recorded prior to induction, at endotracheal intubation and at 3 and 5 minutes post-intubation. Induction quality and pre-induction sedation were scored on 4 point scales. Propofol target required for endotracheal intubation was recorded. Data were analysed using Chi-squared tests, Kruskal-Wallis, one way and general linear model anova (p < 0.05). ResultsAge was significantly lower in group 1 (1.0 (1.0–3.8) years) than group 2 (5.0 (2.0–7.0) years), (median, (IQR)). There were no significant differences in sedation or quality of induction between groups. After premedication, heart rate was significantly lower and arterial blood pressures higher in groups 2 and 3 than group 1, but there was no significant difference between groups 2 and 3. Propofol targets were significantly lower in group 3 (1.5 (1.0–2.5) μg mL−1) than group 1 (2.5 (2.0–3.0) μg mL−1); no significant differences existed between group 2 (2.0 (1.5–2.5) μg mL−1) and the other groups (median, (interquartile range)). Conclusions and Clinical relevanceWhen administered with buprenorphine, at these doses, dexmedetomidine had no advantages in terms of sedation and induction quality over acepromazine. Both doses of dexmedetomidine produced characteristic cardiovascular and respiratory effects of a similar magnitude.

Reduction of interference in oscillometric arterial blood pressure measurement using fuzzy logic

In oscillometry, oscillation amplitudes (OAs) embedded in the cuff pressure are drastically affected by a variety of artifacts and cardiovascular diseases, leading to inaccurate arterial blood pressure (ABP) measurement. The purpose of this paper is to improve the accuracy in the arterial pressure measurement by reducing interference in the OAs using a recursive weighted regression algorithm (RWRA). This method includes a fuzzy logic discriminator (FLD) and a recursive regression algorithm. The FLD is used to reduce the effect of artifacts caused by measurement motion disturbance or cardiovascular diseases, and to determine the truthfulness of the oscillation pulse. According to the truth degree, the relationship between the cuff pressure and OA is reconstructed using the regression algorithm. Because the regression method must utilize inverse matrix operation, which will be difficult to implement in an automatic or ambulatory monitor, the recursive regression method is proposed to solve this problem. To test the performance of this RWRA, 47 subjects underwent the ABP measurement using both the auscultation and the oscillometry combined with the RWRA. It was found that the average difference between the pooled blood pressures measured by the auscultation and those by the oscillometry combined with the RWRA was found to be only 4.9 mmHg. Clinical results demonstrated that the proposed RWRA is more robust than the traditional curve fitting algorithm (TCFA). We conclude that the proposed RWRA can be applied to effectively improve the accuracy of the oscillometric blood pressure measurement.

Evaluation of oscillometric blood pressure monitoring during immobilization of free-ranging Baird's tapirs (Tapirus bairdii) in Costa Rica

The study of free-ranging, endangered species almost always requires immobilization for collection of biological samples and radiotransmitter placement. Although monitoring assists in assuring safe immobilization, scant information is available regarding physiological monitoring of tapirs. This study was designed to test the effectiveness of noninvasive, oscillometric arterial blood pressure monitoring (NIBP) in wild captured tapirs. Six adult Baird's tapirs (Tapirus bairdii) estimated to weigh 235 ± 23.6 kg (mean ± SEM) were attracted to a capture area using ripe bananas as bait. Animals were darted with a mixture of 50 mg butorphanol (0.23 ± 0.03 mg kg−1) and 100 mg xylazine (0.46 ± 0.07 mg kg−1) using a CO2 pistol. Propofol (100 µg kg−1 minute−1 IV, n = 2; 200 µg kg−1 minute−1 IV, n = 2) or ketamine (0.35 ± 0.05 mg kg−1 IV, n = 1) were delivered to maintain immobilization in all but one case. A commercial blood pressure cuff (cuff bladder width to limb circumference ratio 0.399 ± 0.01) was applied to the thoracic limb, and a 20-ga, 3.8 cm catheter was placed in the facial artery on the nondependent side of the laterally recumbent tapir. A laser line-level and careful positioning were used to assure the cuff center and pressure transducer were at the same level, and were at the approximated level of the right atrium. Systolic (SAP), diastolic (DAP) and mean arterial pressure (MAP) were recorded simultaneously (at end cuff decompression). The lower limits of the range of invasive arterial blood pressure (IBP) were 94 ± 18 mm Hg, 58 ± 18 mm Hg and 74 ± 17 mm Hg for SAP, DAP and MAP, respectively. The upper limits of the range of IBP were 114 ± 13 mm Hg, 74 ± 11 mm Hg and 87 ± 13 mm Hg for SAP, DAP, and MAP, respectively. Mean heart rate was 52 ± 9 beats minute−1. To assess agreement and correlation between IBP and NIBP methods of measurement, both correlation analysis and Bland-Altman analysis of agreement (bias and limits of agreement) were performed. Pearson's correlation coefficients were 0.858, 0.801 and 0.912 for SAP, DAP and MAP, respectively. Bias (mean differences) were − 9 mm Hg, − 12 mm Hg and − 7 mm Hg for SAP, DAP and MAP, respectively. The lower limits of agreement were − 21 mm Hg, − 29 mm Hg and − 24 mm Hg for SAP, DAP and MAP, respectively. The upper limits of agreement were 3 mm Hg, 4 mm Hg and 9 mm Hg for SAP, DAP and MAP, respectively. Both correlation and agreement analysis indicated noninvasive oscillometric blood pressure measurement is satisfactory for field blood pressure monitoring, but tend to read falsely low using the described technique.