Continuous Non-invasive Arterial Pressure Research Articles

Non-invasive continuous arterial pressure and cardiac index monitoring with Nexfin after cardiac surgery

This observational study was designed to evaluate the reliability and precision of a new digital photoplethysmographic device (Nexfin, BMEYE B.V., Amsterdam, The Netherlands) for continuous and non-invasive assessment of arterial pressure and cardiac output. Fifty consecutive adult subjects were prospectively enrolled at admission to the intensive care unit after conventional cardiac surgery and investigated hourly from T0 to T4. Simultaneous comparative systolic, diastolic, and mean arterial pressures and cardiac index (CI) data points were collected from an invasive radial artery catheter, transpulmonary thermodilution catheter, and the Nexfin device. Correlations were determined by linear regression. The Bland-Altman analysis was used to compare bias, precision, and limits of agreement. Six (12%) subjects were excluded from the analysis because of the inability to obtain a reliable photoplethysmographic signal. No complications were observed. A significant relationship was found between absolute values of photoplethysmographic and radial systolic (r(2)=0.56, P<0.001), diastolic (r(2)=0.61, P<0.001), and mean (r(2)=0.77, P<0.001) arterial pressures. A significant relationship was also found between transpulmonary thermodilution and Nexfin CI absolute values (r(2)=0.33, P<0.001). Bias, precision, and limits of agreement between the mean photoplethysmographic and radial arterial pressures were 4.6 (95% confidence interval: 3.7-5.5), 6.5, and -17.3 to 8.1 mm Hg, respectively. The percentage error between transpulmonary thermodilution and the Nexfin for CI measurement was 50%. The Nexfin device is safe, convenient, and reliable in measuring continuous non-invasive arterial pressure but not interchangeable with transpulmonary thermodilution to monitor CI.

Prediction of fluid responsiveness by a continuous non-invasive assessment of arterial pressure in critically ill patients: comparison with four other dynamic indices

We evaluated the ability of an infrared photoplethysmography arterial waveform (continuous non-invasive arterial pressure, CNAP) to estimate arterial pulse pressure variation (PPV). We compared the ability of non-invasive PPV to predict fluid responsiveness with invasive PPV, respiratory variation of pulse contour-derived stroke volume, and changes in cardiac index induced by passive leg raising (PLR) and end-expiratory occlusion (EEO) tests. We measured the responses of cardiac index (PiCCO) to 500 ml of saline in 47 critically ill patients with haemodynamic failure. Before fluid administration, we recorded non-invasive and invasive PPVs, stroke volume variation, and changes in cardiac index induced by PLR and by 15 s EEO. Logistic regressions were performed to investigate the advantage of combining invasive PPV, stroke volume variation, PLR, and EEO when predicting fluid responsiveness. In eight patients, CNAP could not record arterial pressure. In the 39 remaining patients, fluid increased cardiac index by ≥15% in 17 'responders'. Considering the 195 pairs of measurements, the bias (sd) between invasive and non-invasive PPVs was -0.6 (2.3)%. The areas under the receiver operating characteristic (ROC) curves for predicting fluid responsiveness were 0.89 (95% confidence interval, 0.78-1.01) for non-invasive PPV compared with 0.89 (0.77-1.01), 0.84 (0.70-0.96), 0.95 (0.88-1.03), and 0.97 (0.91-1.03) for invasive pulse pressure, stroke volume variations, PLR, and EEO tests (no significant difference). Combining multiple tests did not significantly improve the area under the ROC curves. Non-invasive assessment of PPV seems valuable in predicting fluid responsiveness.

Detection of hypotension during Caesarean section with continuous non-invasive arterial pressure device or intermittent oscillometric arterial pressure measurement

The intensified use of spinal anaesthesia (SPA) for Caesarean section significantly contributed to a decreased maternal mortality and morbidity. Nevertheless, one of the major side-effects is hypotension after SPA with potential negative effects on the fetus. Owing to discontinuous oscillometric measurements (non-invasive arterial pressure, NIAP), hypotensive episodes may be missed. Recently, a continuous NIAP measurement device (CNAP) with acceptable agreement with the mean invasive AP was introduced. We hypothesized that CNAP detects hypotensive episodes more reliably compared with NIAP measurements. A total of 65 women undergoing Caesarean section under SPA were included in the study analysis. A total of 888 NIAP measurements obtained at 3 min cycles, starting from before SPA and continued until delivery, were analysed. When averaged over all cycles, the lowest systolic AP identified by CNAP in each cycle [105 mm Hg, (24.4)] was significantly lower (P<0.001) than the average of the individual corresponding single NIAP measurements [126 mm Hg (22.1)] and highest CNAP average [126 mm Hg (24.5)]. Hypotension (systolic AP <100 mm Hg) was detected in 39% of all cycles with CNAP and in 9% with NIAP. Hypotension was detected in 91% of the patients based on CNAP and in 55% based on NIAP. Fetal acidosis defined by an umbilical vein pH under 7.25 did not occur when the lowest systolic AP measured by CNAP was above 100 mm Hg. The CNAP device detected more hypotensive episodes after SPA and significantly lower AP compared with NIAP. AP monitoring based on CNAP may improve haemodynamic management in this patient population with potential benefit for the fetus.

Ability of non‐invasive intermittent blood pressure monitoring and a continuous non‐invasive arterial pressure monitor (CNAP™) to provide new readings in each 1‐min interval during elective caesarean section under spinal anaesthesia

We compared the ability of automated non-invasive intermittent oscillometric blood pressure monitoring with a new device, CNAP(TM) (continuous non-invasive arterial pressure) to provide a new blood pressure reading in each 1-min interval between spinal anaesthesia and delivery during caesarean section. We also compared the accuracy of continuous non-invasive arterial pressure readings with non-invasive blood pressure measurements before spinal anaesthesia. Fifty-nine women participated. The non-invasive and continuous non-invasive monitors displayed new blood pressure readings in a mean of 82% (11%) and 83% (13%) (p = 0.97) of the one-minute intervals between spinal anaesthesia and delivery, respectively. Continuous non-invasive arterial pressure was more likely to fail on two or more consecutive minutes (p=0.001). From the pre-spinal readings, the mean bias, defined as non-invasive-continuous non-invasive arterial pressure, and limits of agreement (±2SD mean bias) for systolic, diastolic and mean blood pressure respectively were +1.3 (±26.0), -2.9 (±21.8) and +2.6 (±20.4) mmHg. The new monitor has disadvantages compared with conventional non-invasive intermittent blood pressure monitoring.

Investigation of the agreement of a continuous non-invasive arterial pressure device in comparison with invasive radial artery measurement

Arterial pressure (AP) monitoring should be accurate, easy to use, free of risks, and ideally continuous. The continuous non-invasive arterial pressure (CNAP) device is non-invasive and provides continuous pressure readings. This study was performed to compare the agreement of CNAP and invasive AP monitoring. Ninety patients undergoing surgery under general anaesthesia were enrolled. Invasive pressure monitoring was established at the radial artery. CNAP monitoring using a finger sensor recording was begun before induction of anaesthesia. Statistical analysis was conducted with the Bland-Altman method for comparisons of repeated measures. We obtained 16 843 valid pressure readings from 85 patients. Mean (sd) bias during maintenance of anaesthesia was: systolic AP: 4.2 (16.5) mm Hg; mean AP (MAP): -4.3 (10.4) mm Hg; and diastolic AP: -5.8 (6) mm Hg. The results of a subgroup analysis of patients who had a mean intra-arterial pressure of <70 mm Hg were as follows: systolic pressure: -0.3 (9.7) mm Hg; mean pressure: -6.8 (7.6) mm Hg; and diastolic pressure: -7.9 (7.2) mm Hg. Bias and percentage error during the induction period were greater in both the main and subgroup analyses, probably due to recalibration being omitted after induction. The CNAP monitor showed an acceptable agreement and was interchangeable with invasive pressure monitoring for MAP during normotensive conditions. During induction of anaesthesia and when the AP was low, the agreement was less good and interchangeability was not achieved. These results suggest that CNAP is not statistically equivalent to invasive monitoring during all periods of anaesthesia but may be a useful additional AP monitor.

A comparison of a continuous noninvasive arterial pressure (CNAP™) monitor with an invasive arterial blood pressure monitor in the cardiac surgical ICU

Accurate measurement and display of arterial blood pressure is essential for rational management of adult cardiac surgical patients. Because of the lower risk of complications, noninvasive monitoring methods gain importance. A newly developed continuous noninvasive arterial blood pressure (CNAP™) monitor is available and has been validated perioperatively. In a prospective study we compared the CNAP™ monitoring device with invasive arterial blood pressure (IAP) measurement in 30 patients in a cardiac surgical Intensive Care Unit (ICU). Patients were either mechanically ventilated or spontaneously breathing, with or without inotropes. CNAP™ was applied on two fingers of the hand contralateral to the IAP monitoring catheter. Systolic, diastolic and mean pressure data were recorded every minute for 2 h simultaneously for both IAP and CNAP™. Statistical analysis included construction of mountain plot and Bland Altman plots for assessing limits of agreement and bias (accuracy) calculation. Three thousand and six hundred pairs of data were analyzed. The CNAP™ systolic arterial pressure bias was 10.415 mmHg and the CNAP™ diastolic arterial pressure bias was -5.3386 mmHg; the mean arterial pressure (MAP) of CNAP™ was close to the MAP of IAP, with a bias of 0.03944 mmHg. The Bland Altman plot showed a uniform distribution and a good agreement of all arterial blood pressure values between CNAP™ and IAP. Percentage within limits of agreement was 94.5%, 95.1% and 99.4% for systolic, diastolic and MAP. Calculated limits of agreement were -4.60 to 25.43, -13.38 to 2.70 and -5.95 to 6.03 mmHg for systolic, diastolic and mean BP, respectively. The mountain plot showed similar results as the Bland Altman plots. We conclude CNAP™ is a reliable, noninvasive, continuous blood pressure monitor that provides real-time estimates of arterial pressure comparable to those generated by an invasive arterial catheter system. CNAP™ can be used as an alternative to IAP.

Continuous noninvasive arterial pressure

To assess the role of continuous noninvasive arterial pressure (CNAP) in elderly, high-risk patients with pronounced variation in arterial pressure (AP) under analgesic sedation. Twenty-nine patients were analyzed while undergoing elective transfemoral aortic valve implantation procedures during periods of normal blood pressure, hypotension, and hypertension with standard invasive arterial pressures (IAP). Systolic, diastolic, and mean IAP were compared with those obtained by CNAP. Data were analyzed to determine precision (i.e. measurement error) and accuracy (i.e. systematic error) during different periods of AP for agreement of the two methods. In addition, we compared the two methods during intervals of functional cardiac arrests (rapid pacing) in terms of amplitude and frequency of rapid changes in AP. No significant differences in precision were observed between CNAP measurements and IAP measurements. CNAP accuracy was -8.3*, 6.4, and 0.6 mmHg in normotensive, -20.5*, 4.4, and -5.5 mmHg in hypertensive, and -4.8, 9.4, and 4.5 mmHg in hypotensive conditions (*P<0.05). The frequency of AP pairs with a difference of ± 15 mmHg (limits of agreement) or less was 59.5, 71.7, and 76.5% in normotensive, 33.1, 72.9, and 66.9% in hypertensive, and 59.5, 71.7, and 76.5% in hypotensive periods for systolic, diastolic, and mean AP, respectively. Rapid pacing intervals showed a significant difference in systolic measurements; whereas the differences between CNAP and IAP for diastolic and mean AP were minimal. The agreement between the two techniques used in this study of elderly high-risk patients under analgesic sedation is similar to that found in studies performed under general anesthesia. The best agreement was detected in hypotensive periods.

Continuous Non-Invasive Finger Arterial Pressure Monitoring Reflects Intra-Arterial Pressure Changes in Children Undergoing Cardiac Surgery

Survey of Anesthesiology: June 2011 - Volume 55 - Issue 3 - p 152-153 doi: 10.1097/01.SA.0000395990.34455.57

Evaluation of a continuous non-invasive arterial blood pressure monitoring device in comparison with an arterial blood pressure measurement in the ICU

Due to a lower risk of complications, non-invasive monitoring methods gain importance. Measuring arterial blood pressure belongs to the standard hemodynamic monitoring. A newly developed continuous non-invasive arterial blood pressure (CNAP) measurement method is available and has been validated perioperatively [1]. We compared the CNAP monitoring device with invasive arterial blood pressure measurement (IBP) as the gold standard in critically ill patients.

Continuous non-invasive finger arterial pressure monitoring reflects intra-arterial pressure changes in children undergoing cardiac surgery

BackgroundContinuous non-invasive measurement of finger arterial pressure (FAP) is a reliable technology in adults. FAP is measured with an inflatable cuff around the finger and simultaneously converted to a reconstructed brachial artery pressure waveform (reBAP) by the Nexfin™ device. We assessed the adequacy of a prototype device (Nexfin-paediatric), designed for a paediatric population, for detecting rapid arterial pressure changes in children during cardiac surgery. MethodsThirteen anaesthetized children with a median age of 11 months (2 months–7 yr) undergoing congenital cardiac surgery were included in the study. reBAP and intra-arterial pressure (IAP) were recorded simultaneously during the surgical procedure. To assess the accuracy of reBAP in tracking arterial pressure changes, the four largest IAP variations within a 5 min time interval were identified from each procedure. These variations were compared offline with reBAP during a 10 s control period before and a 10 s period after an arterial pressure change had occurred. ResultsIn 10 out of 13 children, a non-invasive arterial pressure recording could be obtained. Therefore, recordings from these 10 children were eligible for further analysis, resulting in 40 data points. The correlation coefficient between reBAP and IAP in tracking mean arterial pressure (MAP) changes was 0.98. reBAP followed changes in IAP with a mean bias for systolic, diastolic arterial pressure, and MAP of 0.0 mm Hg (sd 5.8), 0.1 (sd 2.8), and 0.19 (sd 2.7), respectively. ConclusionsThe prototype device closely follows arterial pressure changes in children. However, in a considerable number of attempts, obtaining a signal was time-consuming or unsuccessful. This technique seems promising but requires further technical development.

Precision and accuracy of a new device (CNAP™) for continuous non-invasive arterial pressure monitoring: assessment during general anaesthesia

BackgroundContinuous non-invasive arterial pressure measured with CNAP™ (CNAP) has been shown to be superior to intermittent oscillometric measurements during procedural sedation and spinal anaesthesia. We assessed the performance of CNAP during general anaesthesia by analysis of agreement with invasive measurements of arterial pressure (AP). MethodsEighty-eight patients undergoing elective abdominal surgery, cardio-, or neurosurgery were included in the study. Systolic, diastolic, and mean AP measured by an intra-arterial catheter in the radial artery (IAP) were compared with those obtained by CNAP from the same arm. Data were analysed to determine the precision (i.e. measurement error) and accuracy (i.e. systematic error) of beat-to-beat CNAP values with respect to IAP. Also, we compared the frequency of fast changes in AP (FCAP) and hypotension (IOH) by both methods. ResultsCNAP precision of 4.5, 3.1, and 3.2 mm Hg (systolic, diastolic, and mean AP, respectively) was not significantly different from IAP precision, and CNAP accuracy was +6.7, −5.6, and −1.6 mm Hg. The frequency of AP pairs having a difference within the calculated limits of agreement was 81%, 64%, and 76% for systolic, diastolic, and mean AP, respectively. The calculated limits of agreement were ±17.6, ±11.4, and ±12.0 mm, Hg, respectively. CNAP and IAP detected simultaneously to 82.1% FCAP and to 84.6% IOH. ConclusionsCNAP provides real-time estimates of arterial pressure comparable with those generated by an invasive intra-arterial catheter system during general anaesthesia.

Pulsatile Stress in Middle-Aged Patients With Type 1 or Type 2 Diabetes Compared With Nondiabetic Control Subjects

OBJECTIVEArterial pulse pressure is considered to be an independent cardiovascular risk factor. We compared pulse pressure during an active orthostatic test in middle-aged patients with type 1 diabetes and with type 2 diabetes and corresponding nondiabetic control subjects.RESEARCH DESIGN AND METHODSForty patients with type 1 diabetes (mean age 50 years, diabetes duration 23 years, and BMI 23.0 kg/m2) were compared with 40 nonhypertensive patients with type 2 diabetes (respectively, 50 years, 8 years, and 29.7 kg/m2). Patients taking antihypertensive agents or with renal insufficiency were excluded. All patients were evaluated with a continuous noninvasive arterial blood pressure monitoring (Finapres) in standing (1 min), squatting (1 min), and again standing position (1 min). Patients with type 1 or type 2 diabetes were compared with two groups of 40 age-, sex- and BMI-matched healthy subjects.RESULTSPatients with type 1 diabetes and patients with type 2 diabetes showed significantly higher pulse pressure, heart rate, and double product of pulse pressure and heart rate (PP×HR) (type 1: 5,263 vs. 4,121 mmHg/min, P = 0.0004; type 2: 5,359 vs. 4,321 mmHg, P = 0.0023) levels than corresponding control subjects. There were no significant differences between patients with type 1 diabetes and type 2 diabetes regarding pulse pressure (59 vs. 58 mmHg), heart rate (89 vs. 88/min), and PP×HR (5,263 vs. 5,359 mmHg/min).CONCLUSIONSPatients with type 1 diabetes have increased levels of peripheral PP, an indirect marker of arterial stiffness, and PP×HR, an index of pulsatile stress, comparable to those of nonhypertensive patients with type 2 diabetes at similar mean age of 50 years.

Continuous non-invasive arterial pressure measurement: Evaluation of CNAP™ device during vascular surgery

Objective Standard non-invasive blood pressure (BP) monitoring is an intermittent, discontinuous procedure. Beat-to-beat BP monitoring requires invasive measurement via an arterial catheter and may be associated with serious complications. The Infinity ® CNAP™ SmartPod ® (Dräger Medical AG & Co. KG, Lübeck, Germany) has recently been proposed for non-invasive continuous beat-to-beat BP measurements. The present study was designed to compare BP obtained with the CNAP™ and with an invasive method in the operating room. Study design Prospective study. Patients and methods Twenty-five patients undergoing major vascular surgery were included. Systolic, mean and diastolic BP were monitored invasively (SAP, MAP and DAP respectively) and not invasively using the CNAP™ (CNAP-S, CNAP-M and CNAP-D respectively). Measurements were performed intraoperatively every minute during 1 hour. Results One thousand and five hundred pairs of simultaneous CNAP™ and invasive BP measurements were obtained and 148 were eliminated. The range of BP measurements was 63–205 mmHg for SAP and 57–187 mmHg for CNAP-S, 38–143 mmHg for MAP and 43–142 mmHg for CNAP-M, 29–126 mmHg for DAP and 33–121 mmHg for CNAP-D. Bias and 95% limit of agreement between CNAP™ and invasive BP measurements were respectively 7.2 and −17.7 to 32.2 mmHg for SAP, −1.8 and −22.0 to 18.3 mmHg for MAP, and −7.5 and −27.3 to 12.4 mmHg for DAP. The percentage of CNAP™ measurements with a bias < 10% with the arterial line was 69%, 86% and 91% for systolic, diastolic and mean pressures, respectively. Conclusion Despite low accuracy for SAP and DAP measurements, CNAP™ system seems more accurate for MAP measurement in patients undergoing vascular surgery.

Autonomic dysfunction with early respiratory syncytial virus-related infection

Background Apparent life-threatening events (ALTE) and/or prolonged apnoea have been well-documented during respiratory syncytial virus (RSV) infection in infants less than 2 months of age but fundamental mechanisms remain unclear. The possibility of a central origin for the development of severe cardiac and respiratory events encouraged us, to explore the autonomic nervous system (ANS) profile of infected infants, since ANS activity may contribute to the constellation of symptoms observed during severe forms of RSV bronchiolitis. Methods Eight infants (2 preterm and 6 full-term) less than 2 months of age and presenting with severe and apnoeic forms of RSV infection were evaluated using non-invasive electrophysiological monitoring obtained simultaneously for approximately 2 consecutive hours, including a quiet sleep period. Eight control subjects, paired for gestational and postnatal age, were also evaluated. ANS status was monitored using electrocardiogram recordings and quantified through a frequency-domain analysis of heart rate variability (HRV). This included sympathetic (VLF and LF) and parasympathetic (HF) indices as well as a measure of baroreflex sensitivity (BRS) obtained using non-invasive continuous arterial pressure. Results Regardless of gestational and postnatal age, heart rate variability components (Ptot, VLF, LF, and HF) and baroreflex components (α LF, α HF and sBR) were found to be significantly lower in the RSV-infected group than in the control group ( p < 0.05). Conclusion RSV infection in neonates is associated with profound central autonomic dysfunction. The potentially fatal consequence stresses the importance of maintaining prolonged cardiopulmonary monitoring.

Continuous Arterial Pressure Waveform Analysis Accurately Detects Cardiac Output in Cardiac Surgery: A Prospective Comparison with Thermodilution, Echocardiography, and Magnetic Resonance Techniques

The aim of this study was to compare the accuracy of cardiac output (CO) measurements of noninvasive continuous arterial pressure waveform analysis, thermodilution technique and echocardiography with magnetic resonance (MRI) imaging. Eleven patients who underwent coronary bypass surgery under cardiopulmonary bypass were prospectively enrolled in this study in 2008. Repeated arterial pressure based, thermodilution, echocardiography, and MRI cardiac output measurements were performed at the postoperative 24th hour. Mean CO values were 5.58 +/- 0.98, 5.97 +/- 0.8, 5.31 +/- 0.52, and 5.32 +/- 0.92 measured with MRI, echocardiography, arterial pressure waveform analysis, and thermodilution techniques, respectively. Bland-Altman analysis showed good overall agreement between the MRI vs arterial waveform analysis and MRI vs thermodilution; values for bias +/- SD were -0.27 +/- 1.06 (95% confidence interval [CI] [-2.3 to 1.8]; P = .42) and -0.26 +/- 0.89 (95% CI [-2.0 to 1.5]; P = .34), respectively. Poor agreement was defined between MRI and echocardiography: bias +/- SD, 0.39 +/- 1.28 (95% CI [-2.1 to 2.9]; P = .34). Arterial pressure-based and thermodilution CO measurement systems yielded results comparable to those obtained with cardiac MRI assessment after cardiac surgery. Arterial pressure wave-form analysis systems for CO measurement may be feasible, noninvasive methods for use in cardiac surgery.

The Reliability of Continuous Noninvasive Finger Blood Pressure Measurement in Critically Ill Children

Continuous noninvasive arterial blood pressure can be measured in finger arteries using an inflatable finger cuff (FINAP) with a special device and has proven to be feasible and reliable in adults. We studied prototype pediatric finger cuffs and pediatric software to compare this blood pressure measurement with intraarterially measured blood pressure (IAP) in critically ill children. We included sedated and mechanically ventilated children admitted to our pediatric intensive care unit. We performed simultaneous arterial blood pressure measurements during a relatively stable hemodynamic period and compared FINAP, IAP, and the noninvasive blood pressure oscillometric technique. We also compared IAP to a reconstruction of brachial pressure from finger pressure. Thirty-five children between 2 and 22 kg body weight were included. In total, 152 attempts to record a FINAP pressure were performed of which 4.6% were unsuccessful. When comparing FINAP to IAP, bias was -16.2, -7.7, and -10.2 mm Hg for systolic arterial blood pressure, diastolic arterial blood pressure, and mean arterial blood pressure. Limits of agreement (LOA) were respectively 26.1%, 30.1%, and 22.6%. When reconstruction of brachial pressure from finger pressure was compared to IAP, these results were -11.8, 0.6, and -0.9 mm Hg for bias and 21.7%, 8.9%, and 8.9% for LOA. When noninvasive blood pressure oscillometric technique was compared to IAP, the results were: -6.8, -0.9, and -3.8 mm Hg for bias and 18.2%, 38.6%, and 22.1% for LOA. Beta type continuous noninvasive arterial blood pressure monitoring using a finger cuff with brachial arterial waveform reconstruction seems reliable in hemodynamically stable critically ill children.

Continuous Non-Invasive Arterial Pressure Technique Improves Patient Monitoring during Interventional Endoscopy

Close monitoring of arterial blood pressure (BP) is a central part of cardiovascular surveillance of patients at risk for hypotension. Therefore, patients undergoing diagnostic and therapeutic procedures with the use of sedating agents are monitored by discontinuous non-invasive BP measurement (NIBP). Continuous non-invasive BP monitoring based on vascular unloading technique (CNAP, CN Systems, Graz) may improve patient safety in those settings. We investigated if this new technique improved monitoring of patients undergoing interventional endoscopy. 40 patients undergoing interventional endoscopy between April and December 2007 were prospectively studied with CNAP(R) in addition to standard monitoring (NIBP, ECG and oxygen saturation). All monitoring values were extracted from the surveillance network at one-second intervals, and clinical parameters were documented. The variance of CNAP values were calculated for every interval between two NIBP measurements. 2660 minutes of monitoring were recorded (mean 60.1+/-34.4 min/patient). All patients were analgosedated with midazolam and pethidine, and 24/40 had propofol infusion (mean 90.9+/-70.3 mg). The mean arterial pressure for CNAP was 102.4+/-21.2 mmHg and 106.8+/-24.8 mmHg for NIBP. Based on the first NIBP value in an interval between two NIBP measurements, BP values determined by CNAP showed a maximum increase of 30.8+/-21.7% and a maximum decrease of 22.4+/-28.3% (mean of all intervals). Conventional intermittent blood pressure monitoring of patients receiving sedating agents failed to detect fast changes in BP. The new technique CNAP improved the detection of rapid BP changes, and may contribute to a better patient safety for those undergoing interventional procedures.

Validation of a new continuous non-invasive arterial pressure device in post-surgical patients

Rico-Feijoo, J.; Lopez-Zayas, E.; Arias, D.; Aldecoa, C.; Gomez-Herreras, J. Author Information

Effect of Anesthetics Containing Lidocaine and Epinephrine on Cardiovascular Changes During Dental Implant Surgery

The purpose of this study was to evaluate cardiovascular changes during dental implant surgery using 2% lidocaine with 1:80 000 epinephrine. Eleven normotensive subjects, ranging from 18 to 56 years, were selected to undergo dental implant surgery in the jaw. They were monitored in the pre-, intra-, and postsurgical periods by continuous noninvasive automatic arterial pressure and cardiac frequency measurements taken every 2 minutes. Parameter scores were obtained for the following phases: P1, 15 minutes during preparation of the patient (control period); P2, before anesthesia; P3, immediately after anesthesia; P4, 2 minutes into anesthesia; P5, during incision and detachment; P6, during perforation; P7, during implant placement; P8, during suturing; P9, on completion; and P10, 10 minutes after termination. Individualized statistical analysis for each group during the pre-, intra-, and postoperative periods were performed by analysis of variance. The greatest variations in systolic pressure were increases of 2.29% during phase P2 and 2.59% in phase P5. Diastolic pressure decreased during phase P6 (-2.58%) and increased in P10 (3.27%). The greatest changes in heart rate occurred in phase P10 (-3.24%). There were no statistically significant changes among the evaluated phases (P > .05). In conclusion, there were no changes in the analyzed cardiocirculatory parameters during dental implant surgery (systolic, diastolic, and mean arterial blood pressures and heart rate) in normotensive subjects anesthetized with 2% lidocaine with epinephrine 1:80000.

Determination of optimal atrioventricular delay for cardiac resynchronization therapy using acute non-invasive blood pressure

In this study, we apply non-invasive blood pressure (BP) monitoring, by continuous finger photoplethysmography (Finometer), to detect directly haemodynamic responses during adjustment of the atrioventricular (AV) delay of cardiac resynchronization therapy (CRT), at different heart rates. Twelve patients were studied with six re-attending for reproducibility assessment. At each AV delay, systolic BP relative to a reference AV delay of 120 ms (SBPrel) was calculated. We found that at higher heart rates, altering the AV delay had a more pronounced effect on BP (average range of SBPrel=17.4 mmHg) compared with resting rates (average range of SBPrel=6.5 mmHg), P<0.0001. Secondly, peak AV delay differed between patients (minimum 120 ms, maximum 200 ms). Thirdly, small changes in AV delay had significant BP effects: programming AV delay 40 ms below the peak AV delay reduced SBPrel by 4.9 mmHg (P<0.003); having it 40 ms above the peak decreased SBPrel by 4.4 mmHg (P<0.0005). Finally, the peak AV delay is highly reproducible both on the same day and at 3 months (Bland-Altman difference: 3+/-8 ms). Continuous non-invasive arterial pressure monitoring demonstrates that even small changes in AV delay from its haemodynamic peak value have a significant effect on BP. This peak varies between individuals, is highly reproducible, and is more pronounced at higher heart rates than resting rates.