BACKGROUND: This study aimed to evaluate the accuracy of ankle blood pressure measurements in relation to invasive blood pressure in the lateral position.
METHODS: This prospective observational study included adult patients scheduled for elective non-cardiac surgery under general anesthesia in the lateral position. Paired radial artery invasive and ankle noninvasive blood pressure readings were recorded in the lateral position using GE Carescape B650 monitor. The primary outcome was the ability of ankle mean arterial pressure (MAP) to detect hypotension (MAP < 70 mmHg) using area under the receiver operating characteristic curve (AUC) analysis. The secondary outcomes were the ability of ankle systolic blood pressure (SBP) to detect hypertension (SBP > 140 mmHg) as well as bias (invasive measurement - noninvasive measurement), and agreement between the two methods using the Bland-Altman analysis.
RESULTS: We analyzed 415 paired readings from 30 patients. The AUC (95% confidence interval [CI]) of ankle MAP for detecting hypotension was 0.88 (0.83-0.93). An ankle MAP of ≤ 86 mmHg had negative and positive predictive values (95% CI) of 99 (97-100)% and 21 (15-29)%, respectively, for detecting hypotension. The AUC (95% CI) of ankle SBP to detect hypertension was 0.83 (0.79-0.86) with negative and positive predictive values (95% CI) of 95 (92-97)% and 36 (26-46)%, respectively, at a cutoff value of > 144 mmHg. The mean bias between the two methods was - 12 ± 17, 3 ± 12, and - 1 ± 11 mmHg for the SBP, diastolic blood pressure, and MAP, respectively.
CONCLUSIONS: In patients under general anesthesia in the lateral position, ankle blood pressure measurements are not interchangeable with the corresponding invasive measurements. However, an ankle MAP > 86 mmHg can exclude hypotension with 99% accuracy, and an ankle SBP < 144 mmHg can exclude hypertension with 95% accuracy.

Laparoscopic ovariectomy under general anesthesia was planned in a 10-year-old, 146 kg, apparently healthy female African lion (Panthera leo). The lion was immobilized via intramuscular darts containing midazolam (0.033 mg/kg), medetomidine (50 µg/kg) and ketamine (2.5 mg/kg), and intubated using an endotracheal tube (16 mm internal diameter). The anesthesia was maintained using sevoflurane (0.9-2.1% end-tidal concentration), in combination with remifentanil (0.1 µg/kg/min) and ketamine (11 µg/kg/min) at a constant rate infusion (CRI), with Hartmann\'s solution (5 mL/kg/hr). Surgery was conducted with stable vital signs, but hypotension (mean arterial blood pressure 55 mmHg) developed, requiring dobutamine treatment. The hypotension was effectively controlled by adjusting dobutamine from 5 µg/kg/min to 0.2 to 0.3 µg/kg/min. This case suggests possibilities that dosages in this range can be clinically useful for peri-anesthetic hypotension in lions.

BACKGROUND: Occupational and environmental exposure to chromium compounds such as potassium dichromate (PDC) (K2Cr2O7) has emerged as a potential aetiologic cause for renal disease through apoptotic, and inflammatory reactions. The known potent antioxidants such as nicorandil (NIC) and/or pentoxifylline (PTX) were studied for their possible nephroprotective effect in PDC-treated rats.
METHODS: Forty male Wistar rats were divided into five groups; control, PDC group, NIC+PDC, PTX+PDC group, and combination+PDC group. Nephrotoxicity was evaluated histopathologically and biochemically. Invasive blood pressure, renal function parameters urea, creatinine, uric acid and albumin, glomerular filtration rate markers Cys-C, Kim-1 and NGAL, inflammatory markers IL-1β, IL-6, TNF-α, TGF-β, COX-II, p38MAPK, NF-κB and TLR4, oxidative stress SOD, GSH, MDA, MPO, HO-1 and Nrf2 and apoptotic mediators Notch1 and PCNA were evaluated. Besides, renal cortical histopathology was assayed as well.
RESULTS: PDC led to a considerable increase in indicators for kidney injury, renal function parameters, invasive blood pressure, oxidative stress, and inflammatory markers. They were markedly reduced by coadministration of PDC with either/or NIC and PTX. The NIC and PTX combination regimen showed a more significant improvement than either medication used alone. Our results demonstrated the nephroprotective effect of NIC, PTX, and their combined regimen on PDC-induced kidney injury through suppression of oxidative stress, apoptosis, and inflammatory response.
CONCLUSIONS: Renal recovery from PDC injury was achieved through enhanced MAPK/Nrf2/HO-1 and suppressed Notch1/TLR4/NF-κB signaling pathways. This study highlights the role of NIC and PTX as effective interventions to ameliorate nephrotoxicity in patients undergoing PDC toxicity.

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.

This study aimed to evaluate the accuracy of oscillometric blood pressure measurement at the ankle in children using invasive blood pressure as reference standard. This prospective observational study included children undergoing noncardiac surgery. Paired radial invasive and ankle non-invasive blood pressure measurements were obtained. Delta blood pressure was calculated as the difference between two consecutive readings. The primary outcome was the mean bias and agreement between the two methods using the Bland-Altman analysis. The ISO standard was fulfilled if the mean bias between the two methods was ≤ 5 ± 8 mmHg. Other outcomes included the trending ability of ankle blood pressure using the four-quadrant plot and the accuracy of ankle measurement to detect hypotension using area under receiver operating characteristic curve (AUC) analysis. We analyzed 683 paired readings from 86 children. The mean bias between the two methods for systolic, diastolic, and mean blood pressure (SBP, DBP, MAP) was - 7.2 ± 10.7, 4.5 ± 12.8, and - 1.8 ± 8.2 mmHg, respectively. The concordance rate of ankle blood pressure was 72%, 71%, and 77% for delta SBP, DBP and MAP, respectively. The AUC (95% confidence interval) for ankle MAP ability to detect hypotension was 0.91 (0.89-0.93) with negative predictive value of 100% at cut-off value ≤ 70 mmHg, We concluded that in pediatric population undergoing noncardiac surgery, ankle blood pressure was not interchangeable with the corresponding invasive readings with the ankle MAP having the least bias compared to SBP and DBP. An ankle MAP > 70 mmHg can exclude hypotension with negative predictive value of 100%.

UNASSIGNED: The guidelines of the Surviving Sepsis Campaign suggest using invasive blood pressure (IBP) measurement in septic shock patients, without specifying for a preferred arterial site for accuracy in relation to the severity of septic shock. The objective of this study was to determine the mean arterial pressure (MAP) gradient between the femoral and radial artery sites in septic shock patients.
UNASSIGNED: This prospective study was carried out at a 20-bed ICU in a university hospital. Simultaneous MAP measurements at femoral and radial arterial sites were obtained in septic shock patients receiving norepinephrine (≥0.1 μg/kg/min), with a pre-planned subgroup analysis for those receiving a high dose of norepinephrine (≥0.3 μg/kg/min).
UNASSIGNED: The median norepinephrine dose across all 80 patients studied, including 59 patients on a high dose, was 0.4 (0.28-0.7) μg/kg/min. Overall, simultaneous measurement of MAP (mmHg) at the femoral and radial arterial sites produced mean (95% CI) MAP values of 81 (79-83) and 78 (76-80), respectively, with a mean difference of 3.3 (2.67-3.93), p < 0.001. In Bland-Altman analysis of MAP measurements, the detected effect sizes were 1.14 and 1.04 for the overall and high-dose cohorts, respectively, which indicates a significant difference between the measurements taken at each of the two arterial sites. The Pearson correlation coefficient indicated a weak but statistically significant correlation between MAP gradient and norepinephrine dose among patients receiving a high dose of norepinephrine (r = 0.289; p = 0.026; 95% CI 0.036-0.508).
UNASSIGNED: In septic shock patients, MAP readings were higher at the femoral site than at the radial site, particularly in those receiving a high dose of norepinephrine.
UNASSIGNED: [ClinicalTrials.gov], identifier [NCT03475667].

UNASSIGNED: Non-invasive estimation of central blood pressure (BP) may have better prognostic value than brachial BP. The accuracy of central BP is limited in certain populations, such as in females and the elderly. This study aims to examine whether statistical modeling of central BP for clinical and hemodynamic parameters results in enhanced accuracy.
UNASSIGNED: This study is a cross-sectional analysis of 500 patients who underwent cardiac catheterization. Non-invasive brachial cuff and central BP were measured simultaneously to invasive aortic systolic BP (AoSBP). Central BP was calibrated for brachial systolic (SBP) and diastolic BP (Type I calibration; C1SBP) or brachial mean and diastolic BP (Type II calibration; C2SBP). Differences between central SBP and the corresponding AoSBP were assessed with linear regression models using clinical and hemodynamic parameters. These parameters were then added to C1SBP and C2SBP in adjusted models to predict AoSBP. Accuracy and precision were computed in the overall population and per age or sex strata.
UNASSIGNED: C1SBP underestimated AoSBP by 11.2 mmHg (±13.5) and C2SBP overestimated it by 6.2 mmHg (±14.8). Estimated SBP amplification and heart rate were the greatest predictors of C1- and C2-AoSBP accuracies, respectively. Statistical modeling improved both accuracy (0.0 mmHg) and precision (±11.4) but more importantly, eliminated the differences of accuracy seen in different sex and age groups.
UNASSIGNED: Statistical modeling greatly enhances the accuracy of central BP measurements and abolishes sex- and age-based differences. Such factors could easily be implemented in central BP devices to improve their accuracy.

Calibration affects central blood pressure (BP) estimation accuracy. Factors influencing the accuracy of noninvasive central BP measurement, type of calibration method implemented (systolic/diastolic BP or mean/diastolic BP), and type of BP measurement device used (devices using the transfer function method, directly measurement from the carotid artery, and the transfer function-like method), were investigated. Fifty participants (aged 62.4 ± 8.9 years) without overt heart diseases were recruited. Invasive aortic and radial BP was measured. Simultaneously, noninvasive central BP was measured using three types of devices. The mean invasive aortic BP was 127 ± 19/95 ± 14 mmHg. Noninvasive central BP tended to be slightly lower than invasive BP, though without statistical significance. The type of calibration method did not significantly influence the noninvasive cSBP measurements (p ≥ 0.24). Results from cuff-based devices were significantly lower than invasive measurements (p = 0.04). Multiple regression analyses showed that gender was significantly correlated with the accuracy of noninvasive cSBP measurement. In conclusion, noninvasive cSBP measurements are comparable to invasive measurements but might underestimate true cSBP. The type of device may affect the accuracy of measurement. Either of the two calibration methods is acceptable.

Arterial hypotension is associated with incidence of postoperative complications, such as myocardial infarction or acute kidney injury. Little research has been conducted for the real-time prediction of hypotension, even though many studies have been performed to investigate the factors which affect hypotension events. This forecasting problem is quite challenging compared to diagnosis that detects high-risk patients at current. The forecasting problem that specifies when events occur is more challenging than the forecasting problem that does not specify the event time. In this work, we challenge the forecasting problem in 5 min advance. For that, we aim to build a systematic feature engineering method that is applicable regardless of vital sign species, as well as a machine learning model based on these features for real-time predictions 5 min before hypotension. The proposed feature extraction model includes statistical analysis, peak analysis, change analysis, and frequency analysis. After applying feature engineering on invasive blood pressure (IBP), we build a random forest model to differentiate a hypotension event from other normal samples. Our model yields an accuracy of 0.974, a precision of 0.904, and a recall of 0.511 for predicting hypotensive events.

Accurate measurement of blood pressure (BP) is extremely important in the management of sick preterm newborns. The primary objective of this study was to compare non-invasive blood pressure measurement (NIBP) with invasive blood pressure measurement (IBP) using peripheral arterial cannulation (PAC) in preterm neonates < 37 weeks in the neonatal intensive care unit.
Preterm neonates needing PAC were prospectively enrolled in the study. NIBP measurements were taken in the same limb as that of peripheral arterial line. Initially IBP was recorded followed by NIBP within 1 min using the same monitor. These were called as paired measurements since they are taken within 1 min of each other.
Seventy-three preterm infants with 1703 paired measurements were included in the final analysis (median gestational age 32 weeks, IQR 30-34 weeks, median birth weight 1540 g, IQR 1160-2100 g). In preterm infants not receiving vasoactive agents (n = 51, 1428 paired measurements, Bland-Altman analysis for agreement between invasive mean blood pressure (MBP) and non-invasive mean BP revealed a bias of -2.9123 mmHg (SD 7.8074). The 95% limits of agreement were from -18.2157 to 12.3893 mmHg. In preterm infants with hypotension, we detected a bias of -3.9176 mmHg (SD 5.1135) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -13.9401 to 6.1048 mmHg. In normotensive preterm infants receiving vasoactive agents, we detected a bias of -0.7629 mmHg (SD 8.0539) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -16.5485 to 15.02274 mmHg.
There is poor level of agreement between IBP and NIBP measurements in sick preterm neonates, leading to overestimation or underestimation of blood pressure. The bias was less for mean BP measurements as compared with systolic BP measurements and also for normotensive neonates as compared with hypotensive neonates. Hence, NIBP may be used as a screening method in haemodynamically stable preterm infants, but infants who are haemodynamically unstable and need to be commenced on vasoactive agents should have IBP monitoring.