Eric E. C. de Waal

Validation of a new arterial pulse contour-based cardiac output device.

Objective:To evaluate the accuracy and precision of an arterial pulse contour-based continuous cardiac output device (Vigileo). Vigileo cardiac output (VigileoCO) was compared with intermittent transpulmonary thermodilution cardiac output (TPCO) and an established arterial pulse contour-based cardiac output (PCCO). Design:Prospective clinical study. Setting:University hospital. Patients:Twenty-two patients undergoing coronary artery bypass graft surgery. Interventions:Defined volume load during surgery and in the postoperative period. Measurements and Main Results:We obtained 184 pairs of VigileoCO and TPCO, 140 pairs of VigileoCO and PCCO, and 140 pairs of PCCO and TPCO. Measurements were performed after induction of anesthesia (T1), after sternotomy (T2), immediately after (T3) and 20 mins after volume challenge with 10 mL·kg−1 hydroxyethyl starch 6% (T4), 15 mins after coronary pulmonary bypass (T5), after retransfusion of autologous blood (T6), after arrival at the intensive care unit (T7), and immediately after (T8) and 20 mins after (T9) a second volume load with 10 mL·kg−1 hydroxyethyl starch 6%. TPCO was used to calibrate PCCO. For pooled data, including uncalibrated PCCO data immediately after weaning from coronary pulmonary bypass (T5), the correlation coefficient of TPCO vs. VigileoCO, PCCO vs. VigileoCO, and TPCO vs. PCCO was 0.75, 0.60, and 0.75 respectively. Bland-Altman analysis showed a bias of 0.00, −0.01, and 0.02 L·min−1, the precision (=sd) was 0.87, 1.08, and 0.93 L·min−1, and the mean error was 33%, 40%, and 35%. When we compared calibrated PCCO values (T2–T4, T6, T7–9), the correlation coefficients of PCCO-VigileoCO and TPCO-PCCO were 0.72 and 0.85, bias was −0.16 and 0.19 L·min−1, and mean error was 33% and 27%, respectively. Best correlations and the least differences between TPCO and VigileoCO were observed in postbypass closed-chest conditions and in the intensive care unit. Conclusions:Our results showed that VigileoCO enables clinically acceptable assessment of cardiac output in postbypass closed-chest conditions and during stable conditions in the intensive care unit.

Arterial waveform analysis in anesthesia and critical care.

Purpose of review In this review, we describe the basic principles of arterial waveform analysis (AWA) to assess cardiac output (CO) and cardiac preload. The validity of commercially based hemodynamic monitoring systems is discussed, together with their clinical applications and limitations. Recent findings Currently, three devices (the FloTrac system, PiCCO monitor, and LiDCO system) are available for measurement of AWA-based CO. In addition, dynamic preload parameters such as stroke volume variation (SVV) and pulse pressure variation (PPV) are determined, which may be useful to predict fluid responsiveness in mechanically ventilated patients. Summary AWA provides a less invasive and easy-to-use alternative for CO measurement. The validity of AWA devices has been verified in a variety of patients and circumstances, but their performance is compromised in the presence of hemodynamic instability, cardiac arrhythmias, or other factors disturbing the arterial pressure waveform. The definitive role of dynamic preload parameters like SVV and PPV is a matter of research. Large trials in which the value of early goal-directed therapy using this technology is studied in relation to outcome are urgently needed.

The Effects of Low-Pressure Carbon Dioxide Pneumoperitoneum on Cerebral Oxygenation and Cerebral Blood Volume in Children

We examined the effects of low-pressure carbon dioxide pneumoperitoneum on regional cerebral oxygen saturation (ScO2) and cerebral blood volume (CBV) in children. Fifteen children, ASA I–III, scheduled for laparoscopic fundoplication, were investigated in the head-up position (10°) and ventilated to a baseline end-tidal CO2 (Petco2) between 25 and 33 mm Hg. Ventilatory settings remained unchanged during the operation. ScO2 and CBV were assessed with near-infrared spectroscopy and recorded together with end-tidal and arterial carbon dioxide (Paco2) at 5 time points: before insufflation, 30, 60, and 90 min after the start of CO2 insufflation, and 10 min after desufflation. The intraabdominal pressure was kept between 5 and 8 mm Hg. During insufflation, Petco2 increased from 30.0 ± 2.8 to 38.3 ± 5.1 mm Hg (P < 0.001) and Paco2 increased from 32.0 ± 4.7 to 40.4 ± 5.9 mm Hg (P < 0.001). ScO2 increased by 15.7% ± 8.8% (from 61 ± 9 to 70 ± 9 arbitrary units ) (P < 0.001). CBV increased by 4.6% ± 8.8% (from 123 ± 66 to 128 ± 66 arbitrary units [P = 0.048]). After desufflation, Petco2 and Paco2 decreased, but did not return to preinsufflation values. ScO2 and CBV also decreased after desufflation. In conclusion, hyperventilation and the head-up position before CO2 insufflation are not sufficient to prevent the CO2-mediated cerebral hemodynamic effects of low-pressure pneumoperitoneum (5–8 mm Hg) in children.

Arterial pressure waveform analysis versus thermodilution cardiac output measurement during open abdominal aortic aneurysm repair : A prospective observational study

BACKGROUND Arterial pressure waveform analysis enables continuous, minimally invasive measurement of cardiac output. Haemodynamic instability compromises the reliability of the technique and a means of maintaining accurate measurement in this circumstance would be useful. OBJECTIVES To investigate the accuracy, precision and trending ability of arterial pressure waveform cardiac output obtained with FloTrac/Vigileo, versus pulmonary artery thermodilution in patients undergoing elective open abdominal aortic aneurysm repair. DESIGN A prospective observational study. SETTING Operating room in a university hospital. PATIENTS Twenty-two patients scheduled for elective, open abdominal aortic aneurysm repair. MAIN OUTCOME MEASURES Bias, limits of agreement and mean error as determined with Bland–Altman analysis between arterial waveform and thermodilution cardiac output assessment at four time points: after induction of anaesthesia (t1); after aortic cross-clamping (t2); after clamp release (t3); and after skin closure (t4). Trending ability from t1 to t2, t2 to t3 and t3 to t4, determined with four-quadrant and polar plot methodology. Clinically acceptable boundaries were defined in advance. RESULTS Bland–Altman analysis revealed a bias of 0.54 l min−1 (thermodilution minus arterial waveform cardiac output) for pooled data, and 0.51 (t1), −0.42 (t2), 0.98 (t3) and 0.98 (t4) l min−1 at the different time points. Limits of agreement (LOA) were [–3.0 to 4.0] (pooled), [−2.0 to 3.0] (t1), [−3.1 to 2.3] (t2), [−2.5 to 4.4] (t3) and [−1.7 to 3.7] (t4) l min−1, resulting in mean errors of 58% (pooled), 45% (t1), 53% (t2), 52% (t3) and 41% (t4). Four-quadrant concordance was 65%. Polar plot analysis resulted in an angular bias of −12°, with radial LOA of −60° to 36°. CONCLUSION Bias between arterial waveform and thermodilution cardiac output was within a predefined acceptable range, but the mean error was above the accepted range of 30%. Trending ability was poor. Arterial waveform and thermodilution cardiac outputs are, therefore, not interchangeable in patients undergoing open abdominal aortic aneurysm repair.

Anaesthesia in the cardiac catheterization laboratory.

Purpose of review Interventions in the cardiac catheterization laboratory (CCL) requiring anaesthetic expertise are becoming routine. These interventions involve a heterogeneous patient population and take place in an offsite location. This review aims to give an insight into anaesthetic issues surrounding certain interventions and the challenges encountered in an offsite location. Recent findings Owing to an ageing population with increasing comorbidity, transcatheter interventions are being developed and in certain cases becoming routine alternatives for open heart operations. Percutaneous interventions are also being increasingly performed in adult patients with congenital heart abnormalities. The anaesthetic team plays an important role in these procedures, requiring detailed knowledge of the intervention, the characteristics of the patient population and the ability to work as a team in a complex, multidisciplinary setting. Summary Interventions in the CCL have developed to such an extent that dedicated anaesthesia teams are required in order to cope with the complexities of the patient populations, the interventions and the challenges brought by the offsite nature of the CCL.

Accuracy, Precision, and Trending Ability of Uncalibrated Arterial Pressure Waveform Analysis of Cardiac Output in Patients With Impaired Left Ventricular Function: A Prospective, Observational Study.

OBJECTIVES Uncalibrated arterial waveform analysis provides minimally invasive and continuous measurement of cardiac output (CO). This technique could be of great value in patients with impaired left ventricular function, but the validity in these patients is not well established. The aim of this study was to investigate the accuracy, precision, and trending ability of uncalibrated arterial waveform analysis of cardiac output in patients with impaired left ventricular function. DESIGN Prospective, observational, method-comparison study. SETTING Nonuniversity teaching hospital, single center. PARTICIPANTS The study included 22 patients with a left ventricular ejection fraction of 40% or less undergoing elective coronary artery bypass grafting. INTERVENTIONS In the period between induction of anesthesia and sternotomy, CO was measured using the FloTrac/Vigileo system (third-generation software) and intermittent pulmonary artery thermodilution before and after volume loading. MEASUREMENTS AND MAIN RESULTS Accuracy and precision as determined using Bland-Altman analysis revealed a bias of -0.7 L/min, limits of agreement of -2.9 to 1.5 L/min, and a mean error of 55% for pooled data. Proportional bias and spread were present, indicating that bias and limits of agreement were underestimated for high CO values. Trending ability was assessed using 4-quadrant analysis, which revealed a concordance of 86%. Concordance from a clinical perspective was 36%. Polar plot analysis showed an angular bias of 13° degrees, with radial limits of agreement of -55° to 51°. Polar concordance at±30° was 50%. CONCLUSIONS Arterial waveform analysis of cardiac output and pulmonary artery thermodilution cardiac output were not interchangeable in patients with impaired left ventricular function.

Effects of on-pump and off-pump coronary artery bypass grafting on left ventricular relaxation and compliance: a comprehensive perioperative echocardiography study

AIMS The short-term effect of coronary artery bypass grafting (CABG) on diastolic function is only moderately investigated. Furthermore, it remains unknown whether avoidance of cardioplegic arrest by an off-pump CABG procedure has advantages over on-pump procedure regarding diastolic relaxation and compliance. We investigated whether components of diastolic function would be improved the day after CABG depending on the type of the surgical procedure. METHODS AND RESULTS Spontaneously breathing on-pump (n = 20) and off-pump CABG (n = 12) patients underwent a comprehensive transthoracic echocardiography examination the day before and the day after elective CABG, including transmitral and pulmonary vein flow parameters, colour M-mode flow propagation velocity (Vp) and tissue Doppler assessment of the average mitral annulus diastolic velocity (Em). Isovolumic relaxation and E-wave deceleration time were corrected for heart rate (IVRTcHR and DTcHR). Left ventricular (LV) relaxation time (τ) and LV operating stiffness (LVOS) were calculated. Overall and independent from operation type and preload, CABG decreased IVRTcHR (107 ± 20 vs. 93 ± 15 ms) (P < 0.01) and τ (54 ± 10 vs. 45 ± 10 ms) (P < 0.01), increased Vp (49 ± 22 vs. 75 ± 37 cm/s) (P < 0.01), and increased Em (6.6 ± 2.0 vs. 7.3 ± 1.3 cm/s, P = 0.06), indicating improved relaxation. LVOS increased (0.13 ± 0.06 vs. 0.22 ± 0.05 mmHg/mL) (P < 0.01), compatible with an impaired compliance. A similar improvement in relaxation and impairment in compliance were observed in both groups. CONCLUSION Myocardial relaxation improved the day after CABG irrespective of the use of cardiopulmonary bypass with cardioplegic arrest. Impairment in compliance could not be prevented by the avoidance of cardioplegia.

Chasing the tumor thrombus.

A 65-yr-old woman (height, 152 cm; weight, 90 kg) underwent right radical nephrectomy and tumor thrombectomy without cardiopulmonary bypass for renal cell carcinoma with an intrahepatic inferior vena cava tumor thrombus. Her history revealed recent pulmonary embolism, diabetes, rheumatoid arthritis, vasculitis, obesity, and hypertension. After a midline laparotomy, a large tumorous right kidney was exposed. The inferior vena cava was distended and a large tumor thrombus was located. During ligation of the right renal artery, venous blood loss from a lumbar vein was difficult to control. Suddenly, her hemodynamic condition deteriorated. Her pulmonary artery (PA) and central venous pressures increased, whereas mixed venous oxygen saturation, end-tidal carbon dioxide, arterial blood pressure, and arterial oxygen saturation all decreased. However, continuous cardiac output remained stable. At that very moment, a large tumor embolus was seen floating in the right atrium (Figure 1). The right atrium was seen shifted to the left, indicating increased right atrial pressures, and the right ventricle was enlarged. While viewing this transesophageal echocardiography image, the intracardiac mass was seen to move from the right atrium to the right ventricle and the PA (see video loop available at anesthesia-analgesia.org). An emergent midline sternotomy was performed. After heparinization, the aorta, the right femoral vein, and the superior vena cava were cannulated and hypothermic cardiopulmonary bypass was instituted at 27°C. Right atriotomy was performed, but it failed to reveal an intracardiac mass. Further inspection revealed a tumor embolus in the right ventricle. Moreover, several emboli were extracted from the main PA and its bifurcation. After closure of the cardiac and PA incisions, the remaining intraabdominal portion of the procedure was completed and the patient was weaned from cardiopulmonary bypass. After the operation the patient was transported to the intensive care unit. The postoperative period was complicated by a wound infection. She was tracheally extubated 4 days after the operation and left the hospital in good condition 18 days after the operation. This case demonstrates that accurate preoperative staging and a well-planned surgical approach complemented by invasive hemodynamic monitoring and transesophageal echocardiography contributed to the timely diagnosis and treatment of tumor-thrombus pulmonary embolism.