Impact of blood pressure cuff inflation rates on flow-mediated dilatation and contralateral arm response

Sources of automatic office blood pressure measurement error: a systematic review

OBJECTIVE

Accurate and reliable blood pressure (BP) measurement is important for the prevention and treatment of hypertension. The oscillometric-based automatic office blood pressure measurement (AOBPM) is widely used in hospitals and clinics, but measurement errors are common in BP measurements. There is a lack of systematic review of the sources of measurement errors.

APPROACH

A systematic review of all existing research on sources of AOBPM errors. A search strategy was designed in six online databases, and all the literature published before October 2021 was selected. Those studies that used the AOBPM device to measure BP from the upper arm of subjects were included.

MAIN RESULTS

A total of 1365 studies were screened, and 224 studies were included in this final review. They investigated 22 common error sources with clinical AOBPM. Regarding the causes of BP errors, this review divided them into the following categories: the activities before measurement, patient's factors, measurement environment, measurement procedure, and device settings. 13 sources caused increased systolic and diastolic BP (SBP and DBP), 2 sources caused the decrease in SBP and DBP, only 1 source had no significant effect on BPs, and the other errors had a non-uniform effect (either increase or decrease in BPs). The error ranges for SBP and DBP were -14 to 33 mmHg and -6 to 19 mmHg, respectively.

SIGNIFICANCE

The measurement accuracy of AOBPM is susceptible to the influence of measurement factors. Interpreting BP readings need to be treated with caution in clinical measurements. This review made comprehensive evidence for the need for standardized BP measurements and provided guidance for clinical practitioners when measuring BP with AOBPM devices.

European Society of Cardiology/European Society of Hypertension versus the American College of Cardiology/American Heart Association guidelines on the cut-off values for early hypertension: a microvascular perspective

The aim of this study was to investigate retinal and peripheral microvascular function in asymptomatic individuals that fall into different BP groups when using either the ESC/ESH or the ACC/AHA guidelines. Retinal and peripheral microvascular function was assessed in 358 participants by means of dynamic retinal vessel analysis and digital thermal monitoring, respectively. Blood pressure and lipid panel were also evaluated. Retinal vascular function measured in all groups belonging to the ACC/ASH classifications were within the normal values for age-matched normal population. Individuals classed as grade 1 hypertension according to the ESC/ESH guidelines, however, exhibited a significantly decreased artery baseline (p = 0.0004) and MC (p = 0.040), higher slopeAD (p = 0.0018) and decreased vein MC (p = 0.0446) compared to age matched normal individuals. In addition, they also had significant lower artery baseline, artery BDF, MD and MC than individuals classed as stage 1 hypertension based on the ACC/ASH guidelines (p = 0.00022, p = 0.0179, p = 0.0409 and p = 0.0329 respectively). Peripheral vascular reactivity (aTR) was lower in ESC /ESH grade I compared to those graded ACC/ASH stage I hypertension (p = 0.0122). The conclusion of this study is that microvascular dysfunctions is present at multiple levels only in individuals with ESC/ESH grade 1 hypertension. This observation could be important when deciding personalised care in individuals with early hypertensive changes.

Inter-Day Reliability of Finapres ® Cardiovascular Measurements During Rest and Exercise

This study evaluated the inter-day test-retest reliability of the Finapres ^® finger pulse pressure measuring device during rest and exercise. Eight male participants visited the laboratory twice for evaluation of the inter-day reliability of the Finapres ^® finger-pulse pressure device to measure: heart rate (HR), stroke volume (SV), cardiac output (Q̇) and mean arterial pressure (MAP) at rest, and treadmill walking at 3 km/h on 1% and 5% inclines. There were no systematic biases for any of the variables between days. The coefficient of variation (CV%) and 95% limits of agreement (95% LoA) was smallest for MAP (CV%=1.6–3.2%; LoA total error=4.6–12 mmHg) and HR (CV%=3.2–3.9%; LoA total error=6.8–11.9 b/min), increasing with exercise intensity (gradient). The pattern of error was different for Q̇, with decreasing CV% (4.8–3.8%) and LoA (4.2–5.7 L/min) from rest to 5% gradient, with the larger errors occurring for resting SV (CV=7.4%; LoA total error=21.5 ml). The device measures MAP and HR reliably between days; however, error increases at higher intensities. The measurement of SV is less reliable, probably owing to underlying algorithmic assumptions.

Associations of resting heart rate with endothelium-dependent vasodilation and shear rate

Heart rate is an independent risk factor for cardiovascular disease and a hemodynamic factor that can modulate blood flow as it affects the frequency of shear stimuli acting on the arterial wall. However, the association between heart rate and endothelium-dependent vasodilation remains highly controversial. We determined the association between heart rate at rest and endothelium-dependent vasodilation in 98 apparently healthy adults (18-63 years). The mild and positive association between heart rate and flow-mediated dilation (FMD) was no longer significant when age and sex or baseline diameter were controlled for. The path analyses revealed that heart rate was not directly related to FMD but the association was indirectly mediated by shear rate, which was confirmed by a bias-corrected bootstrap 95% CIs (0.0157-0.1056). We concluded that even though heart rate and endothelium-dependent vasodilation were associated with shear rate, there was no independent relation between heart rate and FMD.

Accuracy in Blood Pressure Monitoring: The Effect of Noninvasive Blood Pressure Cuff Inflation on Intra-arterial Blood Pressure Values

CONTEXT

Both invasive and noninvasive blood pressure (invasive arterial blood pressure [IABP] and noninvasive BP [NIBP]) monitors are used perioperatively; however, they often produce different values. The reason for this discrepancy is not clear, and it is possible that the act of cuff inflation itself might affect the IABP values, especially with the recurrent cycling of NIBP cuff.

AIM

The aim of this study was to determine the effect of ipsilateral NIBP cuff inflation on the contralateral IABP values.

SETTINGS AND DESIGNS

Prospective, observational study.

MATERIALS AND METHODS

One hundred consecutive patients were studied. The NIBP device was set to cycle every 5 min for a total of 6 times. During each cuff inflation cycle, changes in IABP values from the arterial line in the contralateral arm were recorded. A total of 582 measurements were included for data analysis.

STATISTICAL ANALYSIS

Chi-square, paired t-test, analysis of variance.

RESULTS

Mean (± standard deviation) changes in systolic BP (SBP), diastolic BP, and mean BP with cuff inflation were 6.7 ± 5.9, 2.6 ± 4.0, and 4.0 ± 3.9 mmHg, respectively. We observed an increase of 0-10 mmHg in SBP in majority (73.4%) of cuff inflations. The changes in IABP did not differ between the patients with or without hypertension or with the baseline SBP.

CONCLUSIONS

This study showed that there is a transient reactive rise in IABP values with NIBP cuff inflation. This is important information in the perioperative and intensive care settings, where both these measurement techniques are routinely used. The exact mechanism for this effect is not known but may be attributed to the pain and discomfort from cuff inflation.

Flow mediated dilation with photoplethysmography as a substitute for ultrasonic imaging

Flow mediated dilation (FMD) is a non-invasive method for endothelial function assessment providing an index extracted from ultrasonic B-mode images. Although utilized in the research community, the difficulty of its application and high cost of ultrasonic devices prevent it from being widely used in clinical settings. In this study we show that substituting the ultrasonic device with more easily handled and low cost photoplethysmography and electrocardiography is possible. We introduce new indices based on the photoplethysmogram (PPG) and electrocardiogram (ECG) and show that they are correlated with the ultrasound-based FMD Index. To this end, a conventional ultrasound FMD test was carried out whereas PPG and ECG were simultaneously recorded from 20 healthy volunteers (13 M, 7 F) in the age range of 23-32 years. Our results show a significant correlation between our proposed index and ultrasound FMD when using the ECG in conjunction with the PPG (R = 0.77, p < 0.000 01). Using the PPG alone produces a lower correlation (R = 0.72, p < 0.0001). Compared to conventional FMD, the proposed method is low cost and does not require any special operator skills. Hence it may be easily utilized as a screening tool in locations deprived of high-end ultrasound imaging devices.