Non-invasive measurement of pulse pressure variation using a finger-cuff method in obese patients having laparoscopic bariatric surgery

Journal of Clinical Monitoring and Computing - Pulse pressure variation (PPV) is a dynamic cardiac preload variable used to predict fluid responsiveness. PPV can be measured non-invasively using...     

Continuous cardiac output monitoring with pulse contour analysis: a comparison with lithium indicator dilution cardiac output measurement

OBJECTIVE: Pulse contour analysis can be used to provide beat-to-beat cardiac output (CO) measurement. The current study sought to evaluate this technique by comparing its results with lithium dilution CO (LiCO) measurements. DESIGN: Prospective, observational study. SETTING: Surgical intensive care unit. PATIENTS: Twenty-two patients after cardiac or major noncardiac surgery. MEASUREMENTS: After initial calibration of the pulse contour CO (PCO) method, CO was measured by PCO and by LiCO methods at 4, 8, 16, and 24 hrs. Recalibration of PCO was performed every 8 hrs. The systemic vascular resistance and dynamic response characteristics of the arterial catheter-transducer system were measured at each time point to determine whether these influenced the agreement between PCO and LiCO methods. MAIN RESULTS: There was an excellent correlation between methods (r = .94). Bias was small (-0.005 L/min), and clinically acceptable limits of agreement were demonstrated between techniques. Although many catheter-transducer systems had poor dynamic response characteristics, this did not influence the level of agreement between the two techniques. An increase in systemic vascular resistance between two time points did tend to cause overestimation of LiCO by the PCO. CONCLUSIONS: PCO measurement compared well with the lithium dilution method and can be considered an accurate technique for measuring beat-to-beat CO with limited risk to the patient.     

Validation of noninvasive pulse contour cardiac output using finger arterial pressure in cardiac surgery patients requiring fluid therapy

Introduction

Nexfin (Edwards Lifesciences, Irvine, CA) allows for noninvasive continuous monitoring of blood pressure (ABP_NI) and cardiac output (CO_NI) by measuring finger arterial pressure (FAP). To evaluate the accuracy of FAP in measuring ABP_NI and CO_NI as well as the adequacy of detecting changes in ABP and CO, we compared FAP to intra-arterially measured blood pressure (ABP_IA) and transpulmonary thermodilution (CO_TD) in postcardiac surgery patients during a fluid challenge (FC).

Methods

Twenty sedated patients post cardiac surgery were included, and 28 FCs were performed. Measurements of ABP and CO were simultaneously collected before and after an FC, and we compared CO and blood pressure.

Results

Finger arterial pressure was obtainable in all patients. When comparing ABP_NI with ABP_IA, bias was 2.7 mm Hg (limits of agreement [LOA], ± 22.2), 4.9 mm Hg (LOA, ± 13.6), and 4.2 mm Hg (LOA, ± 13.7) for systolic, diastolic, and mean arterial pressure, respectively. Concordance between changes in ABP_NI and ABP_IA was 100%. Mean bias between CO_NI and CO_TD was − 0.26 (LOA, ± 2.2), with a percentage error of 38.9%. Concordance between changes in CO_NI vs CO_TD and was 100%.

Conclusion

Finger arterial pressure reliably measures ABP and adequately tracks changes in ABP. Although CO_NI is not interchangeable with CO_TD, it follows changes in CO closely.     

Anesthetics management of a renal angiomyolipoma using pulse pressure variation and non-invasive cardiac output monitoring: A case report

BACKGROUNDHypovolemic shock can lead to life-threatening organ dysfunction, and adequate fluid administration is a fundamental therapy. Traditionally, parameters such as vital signs, central venous pressure, and urine output have been used to estimate intravascular volume. Recently, pulse pressure variation (PPV) and non-invasive cardiac monitoring devices have been introduced. In this case report, we introduce a patient with massive active bleeding from giant renal angiomyolipoma (AML). During emergent nephrectomy, we used non-invasive cardiac monitoring with CSN-1901 (Nihon Kohden, Tokyo, Japan) and PPV to evaluate the patient''s intravascular volume status to achieve optimal fluid management.CASE SUMMARYA 30-year-old male patient with giant AML with active bleeding was referred to the emergency room complaining of severe abdominal pain and spontaneous abdominal distension. AML was diagnosed by computed tomography, and emergent nephrectomy was scheduled. Massive bleeding was expected so we decided to use non-invasive cardiac monitoring and PPV to assist fluid therapy because they are relatively easy and fast compared to invasive cardiac monitoring. During the surgery, 6000 mL of estimated blood loss occurred. Along with the patient''s vital signs and laboratory results, we monitored cardiac output, cardiac output, stroke volume, stroke volume index with a non-invasive cardiac monitoring device, and PPV using an intra-arterial catheter to evaluate intravascular volume status of the patient to compensate for massive bleeding.CONCLUSIONIn addition to traditional parameters, non-invasive cardiac monitoring and PPV are useful methods to evaluate patient''s intravascular volume status and provide guidance for intraoperative management of hypovolemic shock patients.     

Continuous cardiac output measurement by un-calibrated pulse wave analysis and pulmonary artery catheter in patients with septic shock

Septic shock is a serious medical condition. With increased concerns about invasive techniques, a number of non-invasive and semi-invasive devices measuring cardiac output (CO) have become commercially available. The aim of the present study was to determine the accuracy, precision and trending abilities of the FloTrac and the continuous pulmonary artery catheter thermodilution technique determining CO in septic shock patients. Consecutive septic shock patients were included in two centres and CO was measured every 4 h up to 48 h by FloTrac (APCO) and by pulmonary artery catheter (PAC) using the continuous (CCO) and intermittent (ICO) technique. Forty-seven septic shock patients with 326 matched sets of APCO, CCO and ICO data were available for analysis. Bland and Altman analysis revealed a mean bias ±2 SD of 0.0 ± 2.14 L min^?1 for APCO–ICO (%error = 34.5 %) and 0.23 ± 2.55 L min^?1 for CCO–ICO (%error = 40.4 %). Trend analysis showed a concordance of 85 and 81 % for APCO and CCO, respectively. In contrast to CCO, APCO was influenced by systemic vascular resistance and by mean arterial pressure. In septic shock patients, APCO measurements assessed by FloTrac but also the established CCO measurements using the PAC did not meet the currently accepted statistical criteria indicating acceptable clinical performance.     

心血管患者术后应用脉搏指示连续心排血量监测的护理

选取行心血管大手术治疗的重症患者12例,对其在ICU住院期间采用脉搏指示连续心排血量(PiCCO)进行监护。12例患者应用PiCCO监测2~5d,平均3.5d,未出现与PiCCO操作相关的并发症。患者在ICU进行监护治疗的平均住院时间为6d。 PiCCO能准确、及时和连续地反映患者的心功能情况,为控制患者容量平衡提供指导。合理应用PiCCO并给予严格的导管维护等护理,有助于促进患者的康复,缩短患者在ICU的住院时间。     

Perioperative goal-directed hemodynamic therapy based on radial arterial pulse pressure variation and continuous cardiac index trending reduces postoperative complications after major abdominal surgery: a multi-center,prospective, randomized study

Introduction

Several single-center studies and meta-analyses have shown that perioperative goal-directed therapy may significantly improve outcomes in general surgical patients. We hypothesized that using a treatment algorithm based on pulse pressure variation, cardiac index trending by radial artery pulse contour analysis, and mean arterial pressure in a study group (SG), would result in reduced complications, reduced length of hospital stay and quicker return of bowel movement postoperatively in abdominal surgical patients, when compared to a control group (CG).

Methods

160 patients undergoing elective major abdominal surgery were randomized to the SG (79 patients) or to the CG (81 patients). In the SG hemodynamic therapy was guided by pulse pressure variation, cardiac index trending and mean arterial pressure. In the CG hemodynamic therapy was performed at the discretion of the treating anesthesiologist. Outcome data were recorded up to 28 days postoperatively.

Results

The total number of complications was significantly lower in the SG (72 vs. 52 complications, p = 0.038). In particular, infection complications were significantly reduced (SG: 13 vs. CG: 26 complications, p = 0.023). There were no significant differences between the two groups for return of bowel movement (SG: 3 vs. CG: 2 days postoperatively, p = 0.316), duration of post anesthesia care unit stay (SG: 180 vs. CG: 180 minutes, p = 0.516) or length of hospital stay (SG: 11 vs. CG: 10 days, p = 0.929).

Conclusions

This multi-center study demonstrates that hemodynamic goal-directed therapy using pulse pressure variation, cardiac index trending and mean arterial pressure as the key parameters leads to a decrease in postoperative complications in patients undergoing major abdominal surgery.

Trial registration

ClinicalTrial.gov, {"type":"clinical-trial","attrs":{"text":"NCT01401283","term_id":"NCT01401283"}}NCT01401283.     

高血压病脉压与相对脉搏波速度关系的研究

目的　应用多普勒组织显像(DTI)技术研究原发性高血压患者脉压与主动脉相对脉搏波速度的关系。方法　对91例原发性高血压患者的腹主动脉前壁(AAo)进行PW DTI检查,结合同步心电图描记,测量电机械时间(EMT)、左室射血前期时间(PEP)、脉搏波时间(PWT,PWT=EMT-PEP);同时测量患者身高(H),计算相对脉搏波速度(RPWV,RPWV=H/PWT)。结果　脉压≥60mmHg(1mmHg=0. 133kPa)者的RPWV显著高于脉压<60mmHg者[ (162. 03±27. 87 )m/s和(75. 37±18. 74)m/s, P<0. 001]。RPWV与脉压和年龄显著正相关(脉压r=0. 536,P=0. 000;年龄r=0. 335,P=0. 003)。结论　RPWV与脉压密切相关,可作为一项新的评价动脉硬度的指标应用于高血压病的相关研究。     

Finapres arterial pulse wave analysis with Modelflow is not a reliable non-invasive method for assessment of cardiac output

Non-invasive continuous monitoring of cardiac output could be very useful in clinical care and in research settings, particularly in elderly subjects. We studied whether Finapres arterial pulse wave analysis with Modelflow is a reliable non-invasive method for the assessment of cardiac output in healthy elderly subjects. We compared Modelflow cardiac output (MFCO) with thermodilution cardiac output (TDCO) in 28 healthy subjects, aged 70+/-4 years (mean+/-S.D.). TDCO was measured during right-sided heart catheterization, while MFCO was calculated with Modelflow(R) software from non-invasive arterial Finapres blood pressure, which was measured simultaneously. The two methods were compared using a paired t-test, by Pearson correlation, and by Bland-Altman analysis. TDCO was 6.4+/-1.1 litres/min (mean+/-S.D.) and MFCO was 4.7+/-1.3 litres/min (P<0.001). There was no significant correlation between MFCO and TDCO (r=0.28, P=0.13). Mean difference (bias) was -1.7 litres/min (S.E.M. 0.27 litres/min), with an S.D. (precision) of 1.5 litres/min. The 95% limits of agreement were -4.6 to +1.1 litres/min. In conclusion, non-invasive MFCO values differed significantly from and showed no significant correlation with invasively determined TDCO values in the normal range. Although simple, non-invasive and patient-friendly, the Modelflow method is inaccurate for assessment of cardiac output without invasive calibration.     

Uncalibrated pulse power analysis fails to reliably measure cardiac output in patients undergoing coronary artery bypass surgery

Introduction  

Uncalibrated arterial pulse power analysis has been recently introduced for continuous monitoring of cardiac index (CI). The aim of the present study was to compare the accuracy of arterial pulse power analysis with intermittent transpulmonary thermodilution (TPTD) before and after cardiopulmonary bypass (CPB).     

Comparison of the ability of two continuous cardiac output monitors to measure trends in cardiac output: estimated continuous cardiac output measured by modified pulse wave transit time and an arterial pulse contour-based cardiac output device

Estimated continuous cardiac output (esCCO), a noninvasive technique for continuously measuring cardiac output (CO), is based on modified pulse wave transit time, which in turn is determined by pulse oximetry and electrocardiography. However, its trending ability has never been evaluated in patients undergoing non-cardiac surgery. Therefore, this study examined esCCO’s ability to detect the exact changes in CO, compared with currently available arterial waveform analysis methods, in patients undergoing kidney transplantation. CO was measured using an esCCO system and arterial pressure-based CO (APCO), and compared with a corresponding intermittent bolus thermodilution CO (ICO) method. Percentage error and statistical methods, including concordance analysis and polar plot analysis, were used to analyze results from 15 adult patients. The difference in the CO values between esCCO and ICO was ?0.39 ± 1.15 L min^?1 (percentage error, 35.6 %). And corrected precision for repeated measures was 1.16 L min^?1 (percentage error for repeated measures, 36.0 %). A concordance analysis showed that the concordance rate was 93.1 %. The mean angular bias was ?1.8° and the radial limits of agreement were ±37.6°. The difference between the APCO and ICO CO values was 0.04 ± 1.37 L min^?1 (percentage error, 42.4 %). And corrected precision for repeated measures was 1.37 L min^?1 (percentage error for repeated measures, 42.5 %). The concordance rate was 89.7 %, with a mean angular bias of ?3.3° and radial limits of agreement of ±42.2°. This study demonstrated that the trending ability of the esCCO system is not clinically acceptable, as judged by polar plots analysis; however, its trending ability is clinically acceptable based on a concordance analysis, and is comparable with currently available arterial waveform analysis methods.     

Arterial pressure-based cardiac output in septic patients: different accuracy of pulse contour and uncalibrated pressure waveform devices

Introduction  

We compared the ability of two devices estimating cardiac output from arterial pressure-curve analysis to track the changes in cardiac output measured with transpulmonary thermodilution induced by volume expansion and norepinephrine in sepsis patients.     

Estimated continuous cardiac output based on pulse wave transit time in off-pump coronary artery bypass grafting: a comparison with transpulmonary thermodilution

To evaluate the accuracy of estimated continuous cardiac output (esCCO) based on pulse wave transit time in comparison with cardiac output (CO) assessed by transpulmonary thermodilution (TPTD) in off-pump coronary artery bypass grafting (OPCAB). We calibrated the esCCO system with non-invasive (Part 1) and invasive (Part 2) blood pressure and compared with TPTD measurements. We performed parallel measurements of CO with both techniques and assessed the accuracy and precision of individual CO values and agreement of trends of changes perioperatively (Part 1) and postoperatively (Part 2). A Bland–Altman analysis revealed a bias between non-invasive esCCO and TPTD of 0.9 L/min and limits of agreement of ±2.8 L/min. Intraoperative bias was 1.2 L/min with limits of agreement of ±2.9 L/min and percentage error (PE) of 64 %. Postoperatively, bias was 0.4 L/min, limits of agreement of ±2.3 L/min and PE of 41 %. A Bland–Altman analysis of invasive esCCO and TPTD after OPCAB found bias of 0.3 L/min with limits of agreement of ±2.1 L/min and PE of 40 %. A 4-quadrant plot analysis of non-invasive esCCO versus TPTD revealed overall, intraoperative and postoperative concordance rate of 76, 65, and 89 %, respectively. The analysis of trending ability of invasive esCCO after OPCAB revealed concordance rate of 73 %. During OPCAB, esCCO demonstrated poor accuracy, precision and trending ability compared to TPTD. Postoperatively, non-invasive esCCO showed better agreement with TPTD. However, invasive calibration of esCCO did not improve the accuracy and precision and the trending ability of method.     

A systematic review of pulse pressure variation and stroke volume variation to predict fluid responsiveness during cardiac and thoracic surgery

This systematic review aims to summarize the published data on the reliability of pulse pressure variation (PPV) and stroke volume variation (SVV) to predict fluid responsiveness in an open-chest setting during cardio-thoracic surgery. The analysis included studies reporting receiver operating characteristics or correlation coefficients between PPV/SVV and change in any hemodynamic variables after a fluid challenge test in open-chest conditions. The literature search included seven studies. Increase in cardiac index and stroke volume index after a fluid challenge were the most adopted end-point variables. PPV and SVV showed similar area under the receiver operating characteristic curve values but high heterogeneity among studies. Cardiac and thoracic studies did not differ between PPV/SVV pooled area under the receiver operating characteristic curve. Studies exploring correlation between dynamic indices and end-point variable increase after fluid challenge showed conflicting results. The great heterogeneity between studies was due to small sample size and differences among protocol designs (different monitor devices, mechanical ventilation settings, fluid challenge methodologies, surgical incisions, and end-point variables). PPV and SVV seem to be inaccurate in predicting fluid responsiveness in an open-chest setting during cardio-thoracic surgery. Given the high heterogeneity of published data, more studies are needed to define the role of PPV/SVV in this context.     

高血压病患者颈动脉管径增大指数、单点脉搏波传导速度与脉压差的关系

目的 利用血管回声跟踪技术（ET）测量高血压病患者的颈动脉弹性功能,探讨管径增大指数（AI）、单点脉搏波传导速度（ewv[3）与动脉弹性功能的关系。方法高血压病患者90例,均分为三组：A组肱动脉脉压差〈60mmHg,B组脉压差为60～80mmHg,C组脉压差≥80mmHg。测量患者颈动脉ET参数：硬化指数（B）、压力一应变弹性系数（Ep）、顺应性（AC）、AI、PWV[3及肱动脉脉压差,比较不同脉压差组问颈动脉弹性功能参数的差异。结果A、B、C三组间收缩压依次增高,B、C组收缩期颈动脉内径（Ds）、舒张期颈动脉内径（Dd）较A组增高,差异均有统计学意义（P〈0．05）。B组和C组β、Ep、AC、AI较A组增高,差异有统计学意义（P〈0．05）。AI与年龄、IMT、脉压差呈正相关,与Ds—Dd呈负相关;PwVB与年龄、收缩压、脉压差、Dd呈正相关,与Ds—Dd呈负相关。结论AI、PWVβ随脉压差增大而增大,参数异常早于脉压差增大,二者结合能较敏感地早期反应动脉弹性功能。     

Four-wavelength near-infrared peripheral oximetry in cardiac surgery patients: a comparison between EQUANOX and O3

Near-infrared spectroscopy (NIRS) is a continuous and noninvasive technology that measures regional tissue oxygen saturation (rSO₂). A new 4-wavelength generation of NIRS monitors is now available. We aimed to compare peripheral somatic rSO₂ values given by the 4-wavelength EQUANOX? 7600 device (Nonin Medical Inc., Plymouth, Mn) and O3? device (Masimo Corporation, Irvine, CA). Twenty adult patients scheduled for conventional elective cardiac surgery with cardiopulmonary bypass over a 4-month period were included after local Ethics Committee approval. For each patient, 2 NIRS sensors (EQUANOX and O3) were placed over the medial part of the forearm. Thirteen couples of measurements were performed at predefined intraoperative time points. We compared 260 couples of absolute intraoperative rSO₂ values. No significant difference was found between both monitors: EQUANOX median rSO₂ 60% (95% CI 57–62) versus O3 median rSO₂ 62% (95% CI 61–64), P?=?0.103. Bias was 4.0% and limits of agreement were ±26.3%. Significant correlations were evidenced between EQUANOX and O3 rSO₂ absolute values: rho?=?0.758 (95% CI 0.701–0.806), P?<?0.0001, and rSO₂ percent maximum difference versus baseline: rho?=?0.582 (95% CI 0.188–0.815), P?=?0.007. While absolute values of rSO₂ given by both devices were equivalent and well correlated, the clinical agreement is probably not acceptable, meaning that EQUANOX and O3 are not interchangeable in routine practice.     

Comparison of uncalibrated arterial waveform analysis in cardiac surgery patients with thermodilution cardiac output measurements

Introduction  

Cardiac output (CO) monitoring is indicated only in selected patients. In cardiac surgical patients, perioperative haemodynamic management is often guided by CO measurement by pulmonary artery catheterisation (CO_PAC). Alternative strategies of CO determination have become increasingly accepted in clinical practice because the benefit of guiding therapy by data derived from the PAC remains to be proven and less invasive alternatives are available. Recently, a device offering uncalibrated CO measurement by arterial waveform analysis (CO_Wave) was introduced. As far as this approach is concerned, however, the validity of the CO measurements obtained is utterly unclear. Therefore, the aim of this study was to compare the bias and the limits of agreement (LOAs) (two standard deviations) of CO_Wave at four specified time points prior, during, and after coronary artery bypass graft (CABG) surgery with a simultaneous measurement of the gold standard CO_PAC and aortic transpulmonary thermodilution CO (CO_Transpulm).     

The clinical application of pulse contour cardiac output and intrathoracic volume measurements in critically ill patients.

Cardiac output (CO) determination by pulmonary artery (PA) catheter has increasingly been criticised within the literature due to its invasive nature and poor correlation between the pressure measurements and intravascular volume status in mechanically ventilated patients. Consequently, alternative less invasive technologies to PA catheterisation are emerging within intensive care. One such novel technology are pulse contour CO (PCCO) systems. They establish comprehensive and continuous haemodynamic monitoring utilising a central venous catheter (CVC) and an arterial line. Furthermore, a key feature of this technology is its ability to produce intrathoracic volume measurements which may provide a better estimation of cardiac preload as well as indicate the presence and severity of pulmonary oedema. This article aims to discuss the theoretical basis and clinical application of PCCO systems, how PCCO systems differ from PA catheters and how the intrathoracic volume measurements are derived. Understanding these advanced concepts will ensure that clinicians are able to employ this innovative monitoring technology more effectively.     

助起器的研制及其在腹部大手术后患者中的临床应用

目的 探讨助起器应用于腹部大手术后患者的临床效果.方法 选择2007年1月至2009年6月行腹部大手术患者90例,随机分为观察组和对照组各45例.观察组患者术后6 h后给予自制助起器自己起、卧活动;对照组按传统方法进行坐起、卧下护理,观察对比2组的康复效果.结果 2组患者术后早期肠蠕动功能恢复、切口甲级愈合及并发症压疮的发生率比较差异显著,观察组显著优于对照组.结论 自制助起器的应用,促进了腹部大手术后患者肠蠕动功能的恢复及切口的早期愈合,预防了患者压疮的发生,促进了患者早日康复.