Noninvasive Blood Pressure Readings Research Articles

Accuracy of Noninvasive Blood Pressure Monitoring in Critically Ill Adults.

Background: Blood pressure (BP) is routinely invasively monitored by an arterial catheter in the intensive care unit (ICU). However, the available data comparing the accuracy of noninvasive methods to arterial catheters for measuring BP in the ICU are limited by small numbers and diverse methodologies. Purpose: To determine agreement between invasive arterial blood pressure monitoring (IABP) and noninvasive blood pressure (NIBP) in critically ill patients. Methods: This was a single center, observational study of critical ill adults in a tertiary care facility evaluating agreement (≤10% difference) between simultaneously measured IABP and NIBP. We measured clinical features at time of BP measurement inclusive of patient demographics, laboratory data, severity of illness, specific interventions (mechanical ventilation and dialysis), and vasopressor dose to identify particular clinical scenarios in which measurement agreement is more or less likely. Results: Of the 1852 critically ill adults with simultaneous IABP and NIBP readings, there was a median difference of 6 mm Hg in mean arterial pressure (MAP), interquartile range (1-12), P < .01. A logistic regression analysis identified 5 independent predictors of measurement discrepancy: increasing doses of norepinephrine (adjusted odds ratio [aOR] 1.10 [95% confidence interval, CI 1.08-1.12] P = .03 for every change in 5 µg/min), lower MAP value (aOR 0.98 [0.98-0.99] P < .01 for every change in 1 mm Hg), higher body mass index (aOR 1.04 [1.01-1.09] P = .01 for an increase in 1), increased patient age (aOR 1.31 [1.30-1.37] P < .01 for every 10 years), and radial arterial line location (aOR 1.74 [1.16-2.47] P = .04). Conclusions: There was broad agreement between IABP and NIBP in critically ill patients over a range of BPs and severity of illness. Several variables are associated with measurement discrepancy; however, their predictive capacity is modest. This may guide future study into which patients may specifically benefit from an arterial catheter.

ECG and NIBP Simulators in One Device Display on TFT Nextion

Accurate monitoring of NIBP (Non-Invasive Blood Pressure) parameters using vital sign monitors is crucial for patient care. Therefore, calibration of vital sign monitors is essential to ensure their safety and reliability. The purpose of this study is a vital sign simulator was developed, integrating ECG and NIBP parameters with a TFT Nextion display, to calibrate ECG and NIBP readings on vital sign monitors. The system utilized the Arduino Mega 2560 as the central controller and the MPX5050GP sensor for NIBP measurement and motor pump control. The NIBP parameters were measured at two settings: 60/30 and 80/50. The results showed a maximum systolic error of 3.5% and a diastolic error of 5.6% for the NIBP setting of 80/50. The largest standard deviation value of 2.05 was observed at the NIBP setting of 60/30. The highest uncertainty value of 0.5 was also found in the NIBP 60/30 setting. The obtained data indicated stable module readings within the acceptable threshold for vital sign monitor calibration. The developed vital sign simulator offers a reliable means of calibrating NIBP parameters, enabling accurate blood pressure measurements. Further research and refinement can be conducted to enhance the system's precision and expand its capabilities for calibration of additional vital sign parameters. By ensuring accurate calibration, healthcare professionals can rely on vital sign monitors for effective patient monitoring and diagnosis.

An Evaluation of the NICCI Monitor in Providing Continuous, Noninvasive Blood Pressure Readings in Children During Intraoperative Anesthetic Care

BackgroundIn specific clinical scenarios or with patient comorbid conditions, continuous blood pressure (BP) monitoring may be required as it can be expected to provide superior physiologic monitoring to intermittent techniques. However, continuous BP monitoring requires an arterial cannula (AC) placement, which may be time-consuming, technically challenging, or associated with adverse events. Various noninvasive BP devices have been developed which provide a continuous BP reading. The current study evaluates the accuracy of a novel continuous BP device, the NICCI monitor (NM), in pediatric patients weighing 10 - 40 kg.MethodsThe study cohort included pediatric patients weighing between 10 and 40 kg, scheduled for surgery for which placement of an AC was planned. Systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressure readings were captured from the AC and the NM every second during anesthetic care.ResultsThe study cohort included 24 pediatric patients undergoing major orthopedic, cardiac, and neurosurgical procedures. A total of 146,562 pairs of SBP, DBP, and MAP values from the AC and NC were analyzed. The absolute difference for the NM and the AC’s SBP, DBP, and MAP values were 11 ± 9, 10 ± 7, and 10 ± 7 mm Hg, respectively. The difference between the BP values from the NM and the AC was ≤ 10 mm Hg for 57% of the SBP readings, 60% of the DBP readings, and 56% of the MAP readings. The bias was 4, 4, and 6 mm Hg for the SBP, DBP, and MAP, respectively.ConclusionsAlthough there were some technical limitations given patient size, potentially resulting in variation in accuracy, the NM provided a continuous noninvasive BP measurement within clinically useful limits during a significant portion of anesthetic care compared to values obtained from an AC. Ongoing modification of the technology to improve its application in pediatric patients will likely increase its accuracy.

Accuracy of oscillometric blood pressure measurement at both arms in the lateral position.

To evaluate the accuracy of noninvasive blood pressure (NIBP) measurement at the dependent- and nondependent arms in the lateral position, using invasive blood pressure (IBP) as reference. This prospective observational study included 42 adult patients undergoing surgery in the lateral position. Paired readings of IBP and NIBP were obtained at either arm. The accuracy of both arms in detecting mean arterial pressure (MAP) <70 mmHg was evaluated using the area under the receiver operating characteristic curve (AUC). The agreement between the IBP and NIBP was evaluated using the Bland-Altman and error grid analyses. We analyzed 350 and 347 paired readings at the dependent- and nondependent arms. The AUC for detecting hypotension was comparable in both arms. The negative and positive predictive values (95% confidence interval) were 100% (99-100%) and 24% (14-34%), respectively for the dependent arm at cutoff value MAP ≤86 mmHg; and were 99% (96-100%) and 21% (13-30%), respectively for the nondependent arm at cutoff value MAP ≤75 mmHg. The mean bias for MAP was -6.0 ± 9.1 and 6.3 ± 10.1 mmHg; and for systolic blood pressure was 0.3 ± 11.6 and 13.2 ± 12.6 mmHg, in the dependent- and nondependent arm, respectively. Error grid analysis showed that the proportions of paired MAP readings in risk zone A were 71 and 82% in the dependent- and the nondependent arms, respectively. In the lateral position, the NIBP readings at both arms are not interchangeable with the corresponding IBP readings. However, NIBP measurement at both arms can be used to accurately rule out hypotension.

Accuracy and trending of non-invasive oscillometric blood pressure monitoring at the wrist in obese patients

BackgroundIn obese patients, non-invasive blood pressure monitoring in the arm is difficult due to the arm size and morphology. We compared the non-invasive oscillometric wrist blood pressure measurement with the arm and forearm in obese patients monitored with invasive radial blood pressure (reference standard). MethodsThis prospective observational study included adult obese patients scheduled for bariatric surgery. Non-invasive blood pressure was measured at the arm, upper forearm and wrist of one upper extremity, while invasive blood pressure was simultaneously measured through a radial arterial catheter in the contralateral upper extremity. The accuracy of non-invasive blood pressure reading at each site was evaluated for absolute and trending values using the Bland–Altman analysis and Spearman's correlation coefficient. ResultsIn 40 patients, 262, 259, and 263 pairs of non-invasive blood pressure readings were obtained from the arm, forearm, and wrist sites, respectively. As primary outcome, the correlation coefficient for systolic blood pressure was higher for the wrist (0.92, 95% confidence interval (CI) [0.9–0.94]) than for the arm (0.74, 95% CI [0.68–0.79]) and the forearm (0.71, 95% CI [0.64–0.76]) (P<0.05). The non-invasive systolic wrist blood pressure showed the least mean bias and the narrowest limits of agreement (−0.3±7.6mmHg) when compared with forearm (4.3±16) and arm measurements (14.2±13.6) (P<0.05). For trending values, the correlation coefficient was the highest at the wrist. ConclusionIn obese patients undergoing bariatric surgery, non-invasive blood pressure measured at the wrist showed the highest accuracy in comparison with the arm and forearm.

Discrepancy between invasive and non-invasive blood pressure readings in extremely preterm infants in the first four weeks of life.

BackgroundThe agreement between invasive and non-invasive blood pressure (BP) readings in the first days of life of preterm infants is contentiously debated.ObjectiveTo compare mean, systolic and diastolic invasive (IBP) and non-invasive BP (NBP) readings obtained during routine care in the first four weeks of life of extremely preterm infants.MethodsWe extracted pairs of IBP and NBP readings obtained from preterm infants born below 28 weeks of gestation from the local database. After exclusion of erroneous measurements, we investigated the repeated measures correlation and analyzed the agreement (bias) and precision adjusted for multiple measurements per individual.ResultsAmong 335 pairs of IBP and NBP readings obtained from 128 patients, we found correlation coefficients >0.65 for mean, systolic and diastolic BP values. The bias for mean BP readings was -0.4 mmHg (SD 6.1), for systolic BP readings 6.2 mmHg (SD 8.1), and for diastolic BP readings -4.3 mmHg (SD 6.5). Overestimation of systolic IBP and underestimation of diastolic IBP by the non-invasive measurement were found both in the group with gestational age from 23 to 25.9 weeks and in the group with gestational age from 26 to 27.9 weeks. Systolic NBP readings tended to exceed invasive readings in the range <50 mmHg (bias 9.9 mmHg) whereas diastolic NBP readings were lower than invasive values particularly in the range >30 mmHg (bias -5.5 mmHg).ConclusionThe disagreement between invasive and non-invasive BP readings in infants extends to the first four weeks of life. Biases differ for mean, systolic and diastolic BP values. Our observation implies that they may depend on the range of the blood pressure. Awareness of these biases and preemptive concomitant use of IBP and NPB readings may contribute to reducing over- or under-treatment.

Anaesthetic management of robotic-assisted gynaecology surgery in the morbidly obese - A case series of 46 patients in a UK university teaching hospital.

Background and Aims:The evolution of robotic technology has enhanced the scope of laparoscopic surgery. Morbid obesity [body mass index (BMI) >40 kg/m2] due to significant physiological attributes presents a significant surgical and anaesthetic challenge. Robotic surgery in this subset of patients can present with its own problems due to surgical requirements of prolonged pneumoperitoneum and steep Trendelenburg position.Methods:We reviewed the anaesthetic management of 46 morbidly obese patients undergoing robotic-assisted laparoscopic gynaecology surgery. Patient characteristics, anaesthetic management, length of hospital stay (LOS), complications, and readmissions within 30 days were noted. Mean with standard deviation was used for statistical analysis.Results:The mean [standard deviation (SD)] weight and BMI were 121.2 (18.49) kg and 47.83 (7.89) kg/m2, respectively. The mean (SD) anaesthetic and surgical times were 229 (75.9) and 167.7 (62.7) min, respectively. The mean (SD) LOS was 1.57 (1.03) days. About 70% of patients were discharged on the first day after surgery. Six patients needed critical care support. There were two readmissions within 30 days.Conclusion:Good preparation, teamwork, and multidisciplinary input helped us to conduct complex robotic-assisted and long-duration surgery in morbidly obese patients with minimal complications.

Comparative Analysis and Accuracy of a Devised Automated Non Invasive Blood Pressure Monitor Based on Oscillometric Method

Objectives: This paper focuses on the evaluation of accuracy and reliability of previously designed oscillometric based Non Invasive Blood Pressure (NIBP) instrument by means of a comparative analysis with the standard cuff mercury sphygmomanometer based on auscultation. Methods/Statistical Analysis: Thirty healthy subjects between the ages of 18-23 were examined by successive application of both devices having identical cuffs and site of measurement. The analysis of means and bias values demonstrated that our designed oscillometric NIBP monitor under-read all blood pressure values compared to mercury manometer. Findings: The mean oscillometric NIBP readings (Systolic Blood Pressure (SBP) 119.65 ± 8.25, Diastolic Blood Pressure (DBP) 76.82 ± 6.12 and Mean Arterial Pressure (MAP) 91.1 ± 4.76) were significantly lower than its auscultatory counterpart (SBP 127.03 ± 8.7, DBP 81.4 ± 6.2 and MAP 96.6 ± 4.95). F-test showed that the devised prototype is precise and comparable to a reference mercury manometer. A p-value of <0.05 was recognized to be statistically considerable. Conclusively, the designed NIBP monitoring prototype exhibited a tendency to measure lower blood pressure values than the auscultatory sphygmomanometer; but both devices were well comparable. The difference found, was statistically significant but below the level of physiological significance. Application/Improvements: This oscillometric NIBP prototype may be used for training as well as learning objectives. Furthermore, this prototype can be improved by Arduino based microcontroller and kit in the future studies.

Validation of Noninvasive Measures of Left Ventricular Mechanics in Children: A Simultaneous Echocardiographic and Conductance Catheterization Study

The accuracy of echocardiography in evaluating left ventricular contractility has not been validated in children. The objective of this study was to compare echocardiographic measures of contractility with those derived from pressure-volume loop (PVL) analysis in children. Patients with relatively normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. The gold-standard measure of contractility, end-systolic elastance (Ees), was obtained via balloon occlusion of one or both vena cavae. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Single-beat estimations of echocardiographic Ees were calculated using four different methods. These estimates were calculated using a combination of noninvasive blood pressure readings, ventricular volumes derived from three-dimensional echocardiography, and Doppler time intervals. Of 24 patients, 18 patients were heart transplant recipients, and six patients had small patent ductus arteriosus or small coronary fistulae. The mean age was 9.1±5.6years. The average invasive Ees was3.04±1.65mmHg/mL. Invasive Ees correlated best with echocardiographic Ees by the method of Tanoue (r=0.85, P<.01), with a mean difference of -0.07mmHg/mL (95% limits of agreement, -2.0 to 1.4mmHg/mL). Echocardiographic estimates of Ees correlate well with gold-standard measures obtained via conductance catheters in children with relatively normal loading conditions. The use of these noninvasive measures in accurately assessing left ventricular contractility appears promising and merits further study in children.

Clinical comparison of non-invasive blood pressure measurement at different sites: a systematic review protocol

Review question/objective The objective of this review is to evaluate the accuracy of alternate sites for measuring non-invasive blood pressure when the upper arm is not feasible. More specifically, the objectives are to synthesize the available evidence on the diagnostic accuracy of measuring non-invasive blood pressure on alternate sites, using upper arm as a reference site. Inclusion criteria Types of participants This review will consider studies that evaluate non-invasive blood pressure measurements on healthy volunteers and adult patients who seek treatment in healthcare settings. Individuals who are less than 18 years of age, pregnant or delivering a child will be excluded. Individuals with known or diagnosed vascular diseases or medical conditions that render blood pressure measurements medically inappropriate will also be excluded. Types of intervention(s) This review will consider studies that compare non-invasive blood pressure measurements using oscillometric devices at different sites including but not limited to wrist, forearm, supraorbital artery, thigh, calf and ankle. Studies that report blood pressure measurements obtained from same single site are excluded. The upper arm, as a reference standard in non-invasive blood pressure measurement sites, will be used for comparison. Types of outcomes This review will consider studies that include the following outcome measures: 1. Mean differences in blood pressure measurements (systolic, diastolic and mean arterial pressure). 2. Reported pain score during blood pressure taking.

Measurement of Blood Pressure during Support with a Continuous-Flow Left Ventricular Assist Device in the Outpatient Setting

Purpose Pts with a continuous-flow left ventricular assist device (CF-LVAD) have a reduced pulse pressure making it difficult to measure blood pressure accurately using std. methods. The goal of this study was to determine the optimal method to measure blood pressure in pts with a CF-LVAD when an arterial catheter (a-line) is not available. Methods and Materials Blood pressure measurements were obtained simultaneously from the a-line, single cuff manometer with Doppler, Terumo Elemano ES-H55 double-cuff sphygmomanometer and a noninvasive automatic blood pressure cuff (NIBP). Std. descriptive statistics were calculated and differences were determined using the 2 tailed t-test. Correlations were compared using the Pearson correlation and Dunn and Clark. Results A total of 62 blood pressure measurements were collected on 11 CF-LVAD pts, 8 men (73%) and 3 women (27%), whose mean age was 53 yrs (range, 33-78). There was a significant difference (p figure 1 ] Conclusions Current noninvasive blood pressure readings are inaccurate in patients supported with a CF-LVAD. Although noninvaive blood pressure measurements are significantly different than a-line measurements, SBP measurements correlate significantly with the Doppler, Terumo and NIBP. Additional research with new noninvasive devices is required.

Noninvasive monitoring of blood pressure in the critically ill

In the critically ill, blood pressure measurements mostly rely on automated oscillometric devices pending the intra-arterial catheter insertion or after its removal. If the arms are inaccessible, the cuff is placed at the ankle or the thigh, but this common practice has never been assessed. We evaluated the reliability of noninvasive blood pressure readings at these anatomic sites. Prospective observational study. Medical-surgical intensive care unit. Patients carrying an arterial line with no severe occlusive arterial disease. Each patient underwent a set of three pairs of noninvasive and intra-arterial measurements at each site (arm, ankle, thigh [if Ramsay sedation scale >4]) and, in case of circulatory failure, a second set of measurements after a cardiovascular intervention (volume expansion, change in catecholamine dosage). In 150 patients, whatever the cuff site, the agreement between invasive and noninvasive readings was markedly higher for mean arterial pressure than for systolic or diastolic pressure. For mean arterial pressure measurement, arm noninvasive blood pressure was reliable (mean bias of 3.4 ± 5.0 mm Hg, lower/upper limit of agreement of -6.3/13.1 mm Hg) contrary to ankle or thigh noninvasive blood pressure (mean bias of 3.1 ± 7.7 mm Hg and 5.7 ± 6.8 mm Hg and lower/upper limits of agreement of -12.1/18.3 mm Hg and -7.7/19.2 mm Hg, respectively). During acute circulatory failure (n = 83), arm noninvasive blood pressure but also ankle and thigh noninvasive blood pressure allowed a reliable detection of 1) invasive mean arterial pressure <65 mm Hg (area under the receiver operating characteristic curve of 0.98 [0.92-1], 0.93 [0.85-0.97], and 0.93 [0.85-0.98] for arm, ankle, and thigh noninvasive blood pressure, respectively); and 2) a significant (>10%) increase in invasive mean arterial pressure after a cardiovascular intervention (area under the receiver operating characteristic curve of 0.99 [0.92-1], 0.90 [0.80-0.97], and 0.96 [0.87-0.99], respectively). In our population, arm noninvasive mean arterial pressure readings were accurate. Either the ankle or the thigh may be reliable alternatives, only to detect hypotensive and therapy-responding patients.

Artificial ventilation for basic life support leads to hyperventilation in first aid providers

The ‘Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care — International Consensus on Science’ recommend an artificial ventilation volume of 10 ml/kg bodyweight (equivalent to a tidal volume of 700–1000 ml) without the use of supplemental oxygen in adults with respiratory arrest. For first aid providers using the mouth-to-mouth or mouth-to-nose-ventilation technique, respectively, a ventilation volume of approximately 9.6 l/min results. Additionally, a deep breath is recommended before each ventilation to increase the end-expiratory oxygen concentration of the air exhaled by the first aid provider. To investigate the effects of these recommendations in healthy volunteers, test persons were asked to ventilate an artificial lung model for a period of up to 10 min. The tidal volume was set at 800 ml at a breathing rate of 12/min. End-tidal carbon dioxide, oxygen saturation (measured by pulse oximetry), and heart rate were measured continuously. Capillary blood gas samples were collected and non-invasive blood pressure readings were recorded prior to the start of ventilation and immediately after the end of the measuring period. The data reveal a statistically significant and clinically relevant decrease in end-tidal carbon dioxide pressure ( P<0.001, median decrease 14 mmHg), and the occurrence of hyperventilation-associated symptoms such as paraesthesia, dizziness, and carpopedal spasms in more than 75% of the participants. Clinically and statistically significant hyperventilation results in first aid providers performing artificial ventilation according to the guidelines. This artificial ventilation is associated with a significant decrease in capillary and end-tidal carbon dioxide pressure as well as with multiple symptoms of an acute hyperventilation syndrome. Ventilation performed according to these guidelines may cause injury to the health of the first aid provider. Rescuers ventilating the victim should be replaced at regular intervals and the recommendation to take a deep breath before each ventilation should not be upheld in order to minimise the risk of hyperventilation.

Noninvasive blood pressure measurement in the upper and lower limbs of anaesthetized children

A group of 50 children, aged 5 months to 15 years, and who were undergoing routine surgery under general anaesthesia, were studied to investigate the difference in noninvasive blood pressure readings obtained from inflatable cuffs placed on the upper arm and the lower leg. In contrast to adult data, it was found that the blood pressure measured from the leg in children aged 8 years and under, was significantly lower than that measured from the arm. The leg cuff measurements could not, however, be reliably used to predict arm blood pressure.

Operant conditioning permits voluntary, noninvasive measurement of blood pressure in conscious, unrestrained baboons (Papio cynocephalus)

This report describes a computerized apparatus and procedure for completely automated noninvasive measurement of systolic, diastolic, and mean arterial blood pressure in conscious, unrestrained nonhuman primates. We used a specially constructed, cage-mounted oscillometric blood pressure instrument and operant reward conditioning methods to train adult baboons(Papio cynocephalus) to submit voluntarily to frequent self-initiated determinations of their blood pressures in the absence of a human operator/observer. Details concerning the operant training procedure and illustrative blood pressure data are presented. The accuracy of the method was evaluated by comparing the noninvasive blood pressure readings with simultaneously taken direct measurements obtained by means of chronically indwelling arterial catheters.