Correlation between invasive and noninvasive blood pressure measurements in severely burned children

Evaluation of a novel cuffless photoplethysmography-based wristband for measuring blood pressure according to the regulatory standards

Aims

Elevated blood pressure (BP) is a key risk factor in cardiovascular diseases. However, obtaining reliable and reproducible BP remains a challenge. This study, therefore, aimed to evaluate a novel cuffless wristband, based on photoplethysmography (PPG), for continuous BP monitoring.

Methods and results

Predictions by a PPG-guided algorithm were compared to arterial BP measurements (in the sub-clavian artery), obtained during cardiac catheterization. Eligible patients were included and screened based on AAMI/European Society of Hypertension (ESH)/ISO Universal Standard requirements. The machine learning-based BP algorithm required three cuff-based initialization measurements in combination with ∼100 features (signal-derived and patient demographic-based). Ninety-seven patients and 420 samples were included. Mean age, weight, and height were 67.1 years (SD 11.1), 83.4 kg (SD 16.1), and 174 cm (SD 10), respectively. Systolic BP was ≤100 mmHg in 48 samples (11%) and ≥160 mmHg in 106 samples (25%). Diastolic BP was ≤70 mmHg in 222 samples (53%) and ≥85 mmHg in 99 samples (24%). The algorithm showed mean errors of ±3.7 mmHg (SD 4.4 mmHg) and ±2.5 mmHg (SD 3.7 mmHg) for systolic and diastolic BP, respectively. Similar results were observed across all genders and skin colours (Fitzpatrick I-VI).

Conclusion

This study provides initial evidence for the accuracy of a PPG-based BP algorithm in combination with a cuffless wristband across a range of BP distributions. This research complies with the AAMI/ESH/ISO Universal Standard, however, further research is required to evaluate the algorithms performance in light of the remaining European Society of Hypertension recommendations.

Clinical trial registration

www.clinicaltrials.gov, NCT05566886.

Critical Bias in Critical Care Devices

Critical care data contain information about the most physiologically fragile patients in the hospital, who require a significant level of monitoring. However, medical devices used for patient monitoring suffer from measurement biases that have been largely underreported. This article explores sources of bias in commonly used clinical devices, including pulse oximeters, thermometers, and sphygmomanometers. Further, it provides a framework for mitigating these biases and key principles to achieve more equitable health care delivery.

A prospective comparison of invasive and non-invasive blood pressure in children undergoing cardiac catheterization

BACKGROUND

Blood pressure measurement is a standard of monitoring during general anesthesia. Invasive measurement is considered the gold standard but is less commonly used than non-invasive. Automated oscillometric blood pressure devices measure the mean arterial pressure (MAP) and use an algorithm to determine the systolic and diastolic pressures. Few devices have been validated in children, particularly during anesthesia. Few studies have assessed the agreement between invasive and non-invasive blood pressure measurements in children.

METHODS

This was a multi-center prospective observational study of children under 16 years undergoing cardiac catheterization with general anesthesia. Paired invasive and non-invasive blood pressure measurements were recorded for each patient during stable periods of the procedure. Correlation within and between sites was assessed with Pearson's correlation coefficient, and agreement was examined using Bland-Altman methodology to determine bias. Agreement during episodes of hypotension and for age and weight was also determined. Bias greater than 5 mmHg and standard deviation greater than 8 mmHg was considered clinically significant. The primary end point was agreement of MAP measurements.

RESULTS

A total of 683 paired blood pressure values were collected from 254 children in three pediatric hospitals. Median [IQR] age and weight were 3 [1-7] years and 13.9 [8-23] Kg. The overall bias (SD) for mean arterial pressure values was 7.2 (11.4) mmHg. During hypotension (190 readings), the bias (SD) was 15 (11.0) mmHg. The non-invasive MAP was frequently higher than invasive MAP during infancy, and lower in older children.

CONCLUSION

Automated oscillometric blood pressure measurement is unreliable in anesthetized children during cardiac catheterization. Invasive pressure measurement should be considered for high-risk cases.

Blood pressure monitoring following kidney transplantation in children: a comparison of invasive and noninvasive measurements using Doppler as a benchmark technique

BACKGROUND

Blood pressure (BP) monitoring following pediatric kidney transplantation is essential for optimizing graft perfusion. Differences between invasive BP and noninvasive BP (NIBP) measurements are sometimes considerable. We aimed to assess agreement between invasive BP and NIBP in pediatric patients after kidney transplantation and compare with measurements obtained by systolic Doppler with manual sphygmomanometer as a reference technique.

METHODS

A prospective, observational cohort study, of children aged 18 years or younger, admitted immediately following kidney transplantation to the pediatric intensive care unit of a tertiary, university-affiliated medical center, between May 2019 and June 2021.

RESULTS

Eighty-two paired simultaneous measurements of invasive BP, NIBP, and Doppler BP in 18 patients were compared. Patients were significantly hypertensive, with mean systolic NIBP above the 95th percentile (96 ± 6%). Systolic invasive BP measurements were significantly higher than NIBP (149 ± 20 vs. 136 ± 15 mmHg, p < 0.001). Substantial differences (≥ 20 mmHg) were found in 23% (95% CI 15-34%). Similar disagreement was found between systolic invasive and Doppler BP (150 ± 23 and 137 ± 17 mmHg, respectively, p < 0.001). In contrast, systolic NIBP was in good agreement with Doppler BP (135 ± 17 and 138 ± 18, respectively, p = 0.27). A moderate to strong correlation was found between higher systolic invasive BP and the difference to systolic Doppler BP (Spearman's ρ = 0.63, p < 0.001).

CONCLUSIONS

In children immediately following kidney transplantation, clinically significant disagreement was found between invasive and noninvasive BP measurements. Invasive BP values were significantly higher than those obtained by Doppler. Better agreement was found between NIBP and Doppler. These issues should be considered when interpreting BP measurements in this sensitive patient population. A higher resolution version of the Graphical abstract is available as Supplementary information.

The value of pulmonary artery acceleration time in evaluating pulmonary vascular disease in preterm infants with bronchopulmonary dysplasia

OBJECTIVES

Early screening and dynamic monitoring of pulmonary vascular disease (PVD) in bronchopulmonary dysplasia (BPD) high-risk infants is of great clinical significance. Pulmonary artery acceleration time (PAAT) is a reliable and non-invasive method for assessing PVD in children over 1 year, but to date, few studies have used PAAT to assess pulmonary hemodynamics of preterm infants, especially those with BPD. Through dynamic monitoring the main hemodynamic indicators reflected PVD after birth, this study aimed to assess the value of PAAT in evaluating early PVD in BPD infants.

METHODS

All 81 preterm infants at risk of BPD were divided into BPD and non-BPD groups according to whether BPD occurred. Clinical characteristics, PAAT, right ventricular ejection time (RVET) and other main hemodynamic indicators at four different time points after birth were studied and compared.

RESULTS

PAAT and PAAT/RVET increased gradually within 72 h after birth in the BPD group (p < .05), but the curve tended to be flat over time after 72 h (p > .05). At PMA32 and 36 weeks, the PAAT (49.7 ± 4.8 vs. 54.8 ± 5.7, p = .001; 50.0 ± 5.3 vs. 57.0 ± 5.3, p = .001) and PAAT/RVET (.33 ± .04 vs. .35 ± .03, p = .001; .34 ± .03 vs. .37 ± .04, p = .001) in BPD group were significantly lower than those in the non-BPD group.

CONCLUSIONS

PAAT and PAAT/RVET in the BPD group infants showed different change patterns compared to non-BPD group infants. PAAT can be used as a noninvasive and reliable screening method for screening and dynamic monitoring of PVD in BPD high-risk infants.

Intraoperative Invasive Blood Pressure Monitoring in Flap-Based Lower Extremity Reconstruction

BACKGROUND

Despite the lack of clear indications for the use of intra-arterial lines (IALs) for intraoperative hemodynamic monitoring, they are often used in a variety of settings. In this retrospective review of patients undergoing free tissue transfer (FTT) for lower extremity (LE) reconstruction, we sought to (1) identify patient factors associated with IAL placement, (2) compare hemodynamic measurements obtained via IAL versus noninvasive blood pressure (NIBP) monitoring, and (3) investigate whether method of hemodynamic monitoring affected intraoperative administration of blood pressure-altering medications.

METHODS

Patients undergoing LE FTT from January 2017 through June 2020 were retrospectively reviewed. Patients were pair matched based on flap donor site, sex, and body mass index to identify patient factors associated with IAL placement. Methods previously described by Bland and Altman (Lancet. 1986;327:307-310) were used to investigate agreement between IAL and NIBP measurements.

RESULTS

Sixty-eight patients were included with 34 patients in the IAL group and 34 in the NIBP group. Older patients (P = 0.03) and those with a higher Charlson Comorbidity Index (P = 0.05) were significantly more likely to have an IAL placed. Agreement analysis demonstrated that mean arterial pressures calculated from IAL readings were as much as 31 points lower or 28 points higher than those from NIBP. Bias calculations with this extent of difference suggest poor correlation between IAL readings and NIBP (R2 = 0.3027). There was no significant difference between groups in rate of administration of blood-pressure altering medications.

CONCLUSIONS

Surgeons should consider the risks and benefits of IAL placement on a case-by-case basis, particularly for patients who are young and healthy. Our findings highlight the need for clearer guidance regarding the use of IAL in patients undergoing LE FTT.

Using pulmonary artery acceleration time to evaluate pulmonary hemodynamic changes on preterm infants with respiratory distress syndrome

BACKGROUND

Pulmonary artery acceleration time (PAAT) is a reliable and non-invasive method for assessing pulmonary hemodynamics. To date, few studies have used PAAT to assess preterm infants, especially those with respiratory distress syndrome (RDS). This study aimed to assess changes in PAAT among preterm infants with RDS undergoing pulmonary surfactant (PS) therapy or not, and determine its potential effects on the pulmonary vascular disease (PVD) outcomes of preterm infants with RDS in the late postnatal period.

METHODS

The risk of RDS was reviewed in 62 preterm infants with a gestational age of 26-31 weeks. The infants receiving PS therapy were allocated to the PS group, and the others were allocated to the control group. PAAT, right ventricular ejection time (RVET), and other ultrasonic parameters at 3 different time points after birth were studied and compared.

RESULTS

Infants in the PS group had a significantly lower PAAT (52.7±5.9 vs. 59.6±8.7; P=0.001) and PAAT/RVET (0.30±0.03 vs. 0.33±0.03; P=0.001) than those in the control group at 36 weeks postmenstrual age (PMA). No significant increases in PAAT/RVET were detected at 3 different times for the PS group (P=0.117), but both PAAT and PAAT/RVET increased significantly with time after birth in the control group (P<0.001).

CONCLUSIONS

Preterm infants with RDS might still have PVD in the late postnatal period and thus require long-term follow-up observation. PAAT appears to be a reliable non-invasive screening measure for evaluating pulmonary hemodynamics in preterm infants with RDS and late PVD.

Intraoperative Invasive Blood Pressure Monitoring in Flap-Based Breast Reconstruction: Does It Change Outcomes?

Despite the lack of guidelines regarding the use of intra-arterial lines in postmastectomy breast reconstruction (PMBR), they continue to be used in this setting. In this study of patients undergoing PMBR, we aimed to (1) identify factors associated with intra-arterial line placement, (2) analyze the correlation between intra-arterial monitoring and noninvasive blood pressure (NIBP) monitoring, and (3) investigate whether hemodynamic management differs significantly between patients undergoing intra-arterial blood pressure monitoring versus NIBP.

Development of dynamic cell and organotypic skin models, for the investigation of a novel visco-elastic burns treatment using molecular and cellular approaches

BACKGROUND

Burn injuries are a major cause of morbidity and mortality worldwide. Despite advances in therapeutic strategies for the management of patients with severe burns, the sequelae are pathophysiologically profound, up to the systemic and metabolic levels. Management of patients with a severe burn injury is a long-term, complex process, with treatment dependent on the degree and location of the burn and total body surface area (TBSA) affected. In adverse conditions with limited resources, efficient triage, stabilisation, and rapid transfer to a specialised intensive care burn centre is necessary to provide optimal outcomes. This initial lag time and the form of primary treatment initiated, from injury to specialist care, is crucial for the burn patient. This study aims to investigate the efficacy of a novel visco-elastic burn dressing with a proprietary bio-stimulatory marine mineral complex (MXC) as a primary care treatment to initiate a healthy healing process prior to specialist care.

METHODS

A new versatile emergency burn dressing saturated in a >90% translucent water-based, sterile, oil-free gel and carrying a unique bio-stimulatory marine mineral complex (MXC) was developed. This dressing was tested using LabSkin as a burn model platform. LabSkin a novel cellular 3D-dermal organotypic full thickness human skin equivalent, incorporating fully-differentiated dermal and epidermal components that functionally models skin. Cell and molecular analysis was carried out by in vitro Real-Time Cellular Analysis (RTCA), thermal analysis, and focused transcriptomic array profiling for quantitative gene expression analysis, interrogating both wound healing and fibrosis/scarring molecular pathways. In vivo analysis was also performed to assess the bio-mechanical and physiological effects of this novel dressing on human skin.

RESULTS

This hybrid emergency burn dressing (EBD) with MXC was hypoallergenic, and improved the barrier function of skin resulting in increased hydration up to 24 h. It was demonstrated to effectively initiate cooling upon application, limiting the continuous burn effect and preventing local tissue from damage and necrosis. xCELLigence RTCA® on primary human dermal cells (keratinocyte, fibroblast and micro-vascular endothelial) demonstrated improved cellular function with respect to tensegrity, migration, proliferation and cell-cell contact (barrier formation) [1]. Quantitative gene profiling supported the physiological and cellular function finding. A beneficial quid pro quo regulation of genes involved in wound healing and fibrosis formation was observed at 24 and 48 h time points.

CONCLUSION

Utilisation of this EBD + MXC as a primary treatment is an effective and easily applicable treatment in cases of burn injury, proving both a cooling and hydrating environment for the wound. It regulates inflammation and promotes healing in preparation for specialised secondary burn wound management. Moreover, it promotes a healthy remodelling phenotype that may potentially mitigate scarring. Based on our findings, this EBD + MXC is ideal for use in all pre-hospital, pre-surgical and resource limited settings.

Utility of Pulmonary Artery Acceleration Time to Estimate Systolic Pulmonary Artery Pressure in Neonates and Young Infants

Transthoracic echocardiogram (TTE) is commonly used to screen for pulmonary hypertension (PHTN) in neonates and young infants. However, in the absence of sufficient tricuspid regurgitation (TR), a ventricular septal defect (VSD), or a patent ductus arteriosus (PDA), the estimation of systolic pulmonary artery pressure (SPAP) becomes challenging. Pulmonary artery acceleration time (PAAT) is an alternate parameter that is easy to obtain in almost all patients and does not require the presence of tricuspid valvar regurgitation or an anatomical cardiac defect. We sought to examine the correlation of PAAT with estimated SPAP by TTE and create an equation to estimate the SPAP using PAAT. We performed a retrospective review of TTEs performed on neonates and young infants (4 months of age or younger) at our institution between April 2017 and December 2018, along with the corresponding medical records. We included TTEs that provided estimation for SPAP and at least one PAAT measurement. During the study period, 138 TTEs performed on 82 patients met the inclusion criteria. Strong correlation was delineated between PAAT and SPAP estimated by the maximum velocity of tricuspid valve regurgitation Doppler, correlation coefficient (r) = - 0.83. Moderate correlation was detected between PAAT and SPAP estimated by PDA Doppler, r = - 0.66. Utilizing the following equation "SPAP = 82.6 - 0.58 × PAAT + RA mean pressure", PAAT can be used to estimate SPAP in neonates and young infants. PAAT can be used as an alternative to TR jet to assess SPAP when the latter is absent or insufficient. Further studies are needed to verify the accuracy of this equation.