Non-invasive continuous blood pressure monitoring using the ClearSight system for pregnant women at high risks of post-partum hemorrhage: comparison with invasive blood pressure monitoring during cesarean section

A pilot feasibility study of continuous cardiac output and blood pressure monitoring during intermittent hemodialysis in patients recovering from severe acute kidney injury

PURPOSE

To detect changes in cardiac output and blood pressure during intermittent hemodialysis (IHD) in patients recovering from severe acute kidney injury (AKI) after transition from continuous renal replacement therapy (CRRT).

MATERIAL AND METHODS

In this single-center pilot feasibility study, we applied continuous hemodynamic monitoring (ClearSight System™) before and during IHD sessions in patients recovering from severe AKI. We also measured relative blood volume (BV; CRIT-LINE®IV) and Net Ultrafiltration Rate (NUF). CI changes were categorized as follows: Increase (>5 %), Stable (-5 % to 5 %), Mild Decrease (-5 % to -15 %), Moderate Decrease (-15 % to -25 %), and Severe Decrease (<-25 %).

RESULTS

We enrolled 10 AKI patients. Overall, there were 119 episodes of severe and 286 episodes of moderate reductions in cardiac index (CI). The median time spent with severe and moderate intradialytic reductions in CI was 8.2 min [2.1-115.8] and 49.5 min [21.6-57.5], respectively. Severe CI reductions happened in nine patients out of 10, and in three patients, they lasted more than 2 h. During IHD, mean arterial pressure increased or remained stable in >78 % of measurements, regardless of changes in CI. Overall, CI decreased by -1.14 L/min/m2 during a moderate BV decrease (p < 0.001) and by -0.57 L/min/m2 when NUF rate was high (p < 0.001).

CONCLUSIONS

CI often, repeatedly, and markedly decreased during IHD. Such decreases were not detected by MAP monitoring and were extreme in some patients.

Comparison of the ClearSight™ finger cuff monitor versus invasive arterial blood pressure measurement in elective cardiac surgery patients: a prospective observational study

PURPOSE

To determine the acceptability of the ClearSight™ system (Edwards Lifesciences Corp., Irvine, CA, USA) for continuous blood pressure monitoring during elective cardiac surgery compared with arterial catheterization.

METHODS

We enrolled 30 patients undergoing elective cardiac surgery in a prospective observational study. Blood pressure measurements were recorded every 10 sec intraoperatively. We determined agreement based on the Association for the Advancement of Medical Instrumentation (AAMI) recommendations. Statistical analysis included fixed bias (difference of measurements between methods), percentage error (accuracy between ClearSight measurement and expected measurement from arterial line), and interchangeability (ability to substitute ClearSight monitor without effecting overall outcome of analysis). We used a paired samples t test to compare the time required for placing each monitor.

RESULTS

We found fixed bias in the differences between the ClearSight monitor and invasive arterial blood pressure measurement in systolic blood pressure (SBP; mean difference, 8.7; P < 0.001) and diastolic blood pressure (DBP; mean difference, -2.2; P < 0.001), but not in mean arterial pressure (MAP; mean difference, -0.5; P < 0.001). Bland-Altman plots showed that the means of the limits of agreement were greater than 5 mm Hg for SBP, DBP, and MAP. The percentage errors for SBP, DBP, and MAP were lower than the cutoff we calculated from the invasive arterial blood pressure measurements. Average interchangeability rates were 38% for SBP, 50% for DBP, and 50% for MAP. Placement of the ClearSight finger cuff was significantly faster compared with arterial catheterization (mean [standard deviation], 1.7 [0.6] min vs 5.6 [4.1] min; P < 0.001).

CONCLUSIONS

In this prospective observational study, we did not find the ClearSight system to be an acceptable substitute for invasive arterial blood pressure measurement in elective cardiac surgery patients according to AAMI guidelines. Nevertheless, based on statistical standards, there is evidence to suggest otherwise.

STUDY REGISTRATION

ClinicalTrials.gov ( NCT05825937 ); first submitted 11 April 2023.

Finger cuff versus invasive and noninvasive arterial pressure measurement in pregnant patients with obesity

BACKGROUND

Pregnant patients with obesity may have compromised noninvasive blood pressure (NIBP) measurement. We assessed the accuracy and trending ability of the ClearSight™ finger cuff (FC) with invasive arterial monitoring (INV) and arm NIBP, in obese patients having cesarean delivery.

METHODS

Participants were aged ≥18 years, ≥34 weeks gestation, and body mass index (BMI) ≥ 40 kg m-2. FC, INV, and NIBP measurements were obtained across 5-min intervals. The primary outcome was agreement of FC measurements with those of the reference standard INV, using modified Bland-Altman plots. Secondary outcomes included comparisons between FC and NIBP and NIBP versus INV, with four-quadrant plots performed to report discordance rates and evaluate trending ability.

RESULTS

Twenty-three participants had a median (IQR) BMI of 45 kg m-2 (44-48). When comparing FC and INV the mean bias (SD, 95% limits of agreement) for systolic blood pressure (SBP) was 16 mmHg (17, -17.3 to 49.3 mmHg), for diastolic blood pressure (DBP) -0.2 mmHg (10.5, -20.7 to 20.3), and for mean arterial pressure (MAP) 5.2 mmHg (11.1, -16.6 to 27.0 mmHg). Discordance occurred in 54 (26%) pairs for SBP, 41 (23%) for DBP, and 41 (21.7%) for MAP. Error grid analysis showed 92.1% of SBP readings in Zone A (no-risk zone). When comparing NIBP and INV, the mean bias (95% limits of agreement) for SBP was 13.0 mmHg (16.7, -19.7 to 29.3), for DBP 5.9 mmHg (11.9, -17.4 to 42.0), and for MAP 8.2 mmHg (11.9, -15.2 to 31.6). Discordance occurred in SBP (84 of 209, 40.2%), DBP (74 of 187, 39.6%), and MAP (63 of 191, 33.0%).

CONCLUSIONS

The FC and NIBP techniques were not adequately in agreement with INV. Trending capability was better for FC than NIBP. Clinically important differences may occur in the setting of the perfusion-dependent fetus.

Use of vasopressors to manage spinal anesthesia-induced hypotension during cesarean delivery

Cesarean sections are commonly performed under spinal anesthesia, which can lead to hypotension, adversely affecting maternal and fetal outcomes. Hypotension following spinal anesthesia is generally defined as a blood pressure of 80-90% below the baseline value. Various strategies have been implemented to reduce the incidence of spinal anesthesia-induced hypotension. The administration of vasopressors is a crucial method for preventing and treating hypotension. In the past decade, phenylephrine, a primarily alpha-adrenergic agonist, has been the preferred vasopressor for cesarean sections. Recently, norepinephrine, a potent alpha-agonist with modest beta-agonist activity, has gained popularity owing to its advantages over phenylephrine. Vasopressors can be administered via a bolus or continuous infusion. Although administering boluses alone is simpler in a clinical setting, continuous prophylactic infusion initiated immediately after spinal anesthesia is more effective in reducing the incidence of hypotension. Tailoring the infusion dose based on the patient's body weight and adjusting the rate in response to blood pressure changes, in addition to using a prophylactic or rescue bolus, helps reduce blood pressure variability during cesarean sections under spinal anesthesia until neonatal delivery.