Accuracy of Continuous Central Venous Oxygen Saturation Monitoring in Patients Undergoing Cardiac Surgery

Objective: Continuous assessment of central venous oxygen saturation (ScevoxO2) with the CeVOX device (Pulsion Medical Systems, Munich, Germany) was evaluated against central venous oxygen saturation (ScvO2) determined by co-oximetry. Methods: In 20 cardiac surgical patients, a CeVOX fiberoptic probe was introduced into a standard central venous catheter placed in the right internal jugular vein and advanced 2-3cm beyond the catheter tip. After invivo calibration of the probe, ScevoxO2, ScvO2, mixed venous oxygen saturation (SmvO2) haemoglobin (Hb), body temperature, heart rate, central venous and mean arterial pressure, and cardiac index were assessed simultaneously at 30min intervals during surgery and at 60min intervals during recovery in the intensive care unit. Agreement between ScevoxO2, and ScvO2 was determined by Bland-Altman analysis. Simple regression analysis was used to assess the correlation of ScevoxO2, and ScvO2 to Hb, body temperature and haemodynamic parameters. Results: Values of ScevoxO2 and ScvO2 (84 data pairs during surgery and 106 in the intensive care unit) ranged between 45-89% and 43-90%, respectively. Mean bias and limits of agreement of ScevoxO2 and ScvO2 were -0.9 (−7.9/+6.1)% during surgery and −1.2 (−10.5/+8.1)% in the intensive care unit. In 37.9% of all measured data pairs, the difference between ScevoxO2 and ScvO2 was beyond clinically acceptable limits (≥1 s.d.). Mean bias was significantly influenced by cardiac index. Sensitivity and specificity of ScevoxO2 to detect substantial (≥1 s.d.) changes in ScvO2 were 89 and 82%, respectively. Conclusions: In adult patients during and after cardiac surgery, the current version of the CeVOX device might not be the tool to replace ScvO2 determined by co-oxymetry, although sensitivity and specificity of ScevoxO2 to predict substantial changes in ScvO2 were acceptabl

Accuracy of a Novel Approach to Measuring Arterial Thermodilution Cardiac Output During Intra-Aortic Counterpulsation

Objective: To assess the agreement between a novel approach of arterial and the pulmonary artery bolus thermodilution for measuring cardiac output in critically ill patients during aortic counterpulsation. Methods: Eighteen male patients aged 37-80years, undergoing preoperative insertion of an intra-aortic balloon pump (IABP) and elective coronary artery bypass grafting. A thin 1.3FG thermistor was introduced through the pressure lumen to the tip of an 8FG IABP catheter, and the pump rate was set at 1:1. After arrival in the intensive care unit cardiac output (CO) was measured under haemodynamic steady-state conditions hourly for 8-11h, and arterial bolus thermodilution (BCOiabp) and pulmonary artery bolus thermodilution (BCOpulm) were determined after the patients' admission to the intensive care unit. Results: A total of 198 data pairs were obtained: 177 with aortic counterpulsation and 21 without. During aortic counterpulsation, median CO was 6.8l/min for BCOiabp and 6.1l/min for BCOpulm, without aortic counterpulsation; corresponding values were 7.1l/min for BCOiabp and 6.5l/min for BCOpulm with aortic counterpulsation. Mean bias was +0.77l/min, limits of agreement ( ± 2SD) were -1.27/+2.81l/min, and mean error (2SD/[(BCOiabp+BCOpulm)/2] was 31.4%. Without aortic counterpulsation, corresponding values were +0.43l/min, -1.03/+1.87l/min, and 22.4%. Conclusions: Agreement between BCOiabp and BCOpulm was satisfactory for CO values between 2.0 and 10l/min only without aortic counterpulsation. BCOiabp CO measurements during aortic counterpulsation after coronary artery bypass grafting cannot be recommended at the present tim

Clinical Validation of a Digital Transcutaneous PCO2/SpO2 Ear Sensor in Adult Patients after Cardiac Surgery

Objective: The aim of this study was to validate the V-Sign digital sensor (SenTec AG, Therweil, Switzerland) for combined noninvasive assessment of pulse oxymetric oxygen saturation (SpO2) and transcutaneous carbon dioxide tension (PtcCO2) in adults after cardiac surgery. Methods: In twenty one patients, aged 51-86years, simultaneous measurements of blood gases with the V-Sign Sensor and with two Nellcor Durasensors (model DS-100A), one at the opposite earlobe and one with a finger clip, were compared first during hyper-, normo- and hypocapnia and at different pulse rates using a pacemaker, and then at 2-h intervals up to 8h. Agreement was assessed by Bland-Altman analysis. Results: PtcCO2 data of three patients were excluded because of calibration failure of the device. Median (range) PtcCO2 for the remaining patients was 5.49 (3.3-7.6) kPa and arterial carbon dioxide tension (PaCO2) was 5.43 (3.61-7.41) kPa. Corresponding mean bias was +0.05kPa and limits of agreement (LOA) were −1.2/+1.3kPa. During normo- and hypoventilation, mean bias was good at +0.02 and +0.04kPa respectively, but limits of agreement were poor at −0.67/+0.69 and −0.81/+0.88kPa. In 10 patients, an initial overshoot of PtcCO2 was observed. Mean bias of SpO2 and pulse rate was close to zero (−1.5% and +0.001bpm respectively), but limits of agreement were unacceptably high (−21.4/+18.4% and −22.3/+22.3bpm). Conclusions: In the present state of development the SenTeC Digital monitor V-Sign device has serious limitations. Additional efforts are necessary to eliminate calibration failures and the initial overshoot of PtcCO2 as well as to improve detection of SpO2 and pulse rat

Cement-augmented dorsal instrumentation of the spine as a safe adjunct to the multimodal management of metastatic pheochromocytoma: a case report

Malignant pheochromocytoma is a neuroendocrine tumor that originates from chromaffin tissue. Although osseous metastases are common, metastatic dissemination to the spine rarely occurs

Off-pump surgery for the poor ventricle?

Severely decreased ejection-fraction is an established risk-factor for worse outcome after cardiac surgery. We compare outcomes of off-pump coronary artery bypass grafting (OPCAB) and on-pump CABG (ONCABG) in patients with severely compromised EF. From 2004 to 2009, 478 patients with a decreased EF ≤35% underwent myocardial-revascularization. Patients received either OPCAB (n=256) or ONCABG (n=222). Propensity score (PS), including 50 preoperative risk-factors, was used to balance characteristics between groups. PS adjusted logistic regression analysis was performed to assess mortality and major adverse cardiac and cerebrovascular events (MACCE). A composite endpoint for major non-cardiac complications such as respiratory failure, renal failure, rethoracotomy was applied. Complete revascularization (CR) was assumed when the number of distal anastomoses was larger than that of diseased vessels. There was no difference for mortality (2.3 vs. 4.1%; PS-adjusted odds ratio (PS-OR)=1.05; p=0.93) and MACCE (13.7 vs. 17.6%; PS-OR=1.22; p=0.50) including myocardial-infarction (1.4 vs. 4.9%; PS-OR=0.39; p=0.26), low cardiac output (2.3 vs. 4.7%; PS-OR=0.75; p=0.72) and stroke (2.3 vs. 2.7%; PS-OR=0.69; p=0.66). OPCAB patients presented with a trend to less frequent occurrence of the non-cardiac composite (12.1 vs. 22.1%; PS-OR=0.54; p=0.059) including renal dysfunction (PAOR=0.77; 95% CI 0.31-1.9; p=0.57), bleeding (PAOR=0.42; 95% CI 0.14-1.20; p=0.10) and respiratory failure (PAOR=0.39; 95% CI 0.05-3.29; p=0.39). The rate of complete revascularization was similar (92.2 vs. 92.8%; PS-OR=0.75; p=0.50). OPCAB in patients with severely decreased EF is safe and feasible. It may even benefit these patients in regard to non-cardiac complications and does not come at cost of less complete revascularizatio

Transcutaneous continuous carbon dioxide tension monitoring reduced incidence, degree and duration of hypercapnia during combined regional anaesthesia and monitored anaesthesia care in shoulder surgery patients

We studied the impact of transcutaneous continuous carbon dioxide tension (PtcCO2) monitoring on ventilation and oxygenation during monitored anaesthesia care (MAC) in patients scheduled for shoulder surgery with continuous interscalene block. 50 patients were randomised either to the intervention (I-group) or the control (C-group) group. In both groups MAC was performed using target controlled infusion of propofol and remifentanil. MAC regimen was adapted to PtcCO2 values in the I-group, whereas the C-group was blinded for these values. Primary outcome was the incidence, degree and duration of hypoventilation stages. In the I-group and the C-group the mean ± SD [range] of PtcCO2 and PaCO2 was 5.79 ± 0.84 [4.37] and 5.44 ± 0.59 [2.78] kPa, as well as 6.41 ± 1.17 [6.29] and 6.01 ± 0.96 [7.15] kPa. Periods of PtcCO2/PaCO2 > 6.5 kPa were 21.0 ± 35.7/1.2 ± 4.2 min in the I-group and 45.6 ± 40.0/18.6 ± 26.8 min in the C-group. Severe hypercapnia (PtcCO2 and/or PaCO2 > 7.5 kPa) was dected in 3/0 patients of the I-group and in 10/3 patients of the C-group. PtcCO2 and PaCO2 showed a strong correlation (r = 0.78), but only moderate agreement with a mean bias (LOA) of −0.37 (−1.69; +0.95) kPa showing an overestimation of the PaCO2. Sensitivity and specificity of PtcCO2 to detect changes of PaCO2 was 0.94 and 0.56, respectively. In no patient SpO2 or SaO2 values lower than 90 % were measured. Despite a moderate agreement between PaCO2 and PtcCO2 the PtcCO2 monitoring significantly reduced incidence, degree and duration of hypercapnia in shoulder surgery patients with MAC

Transcutaneous continuous carbon dioxide tension monitoring reduced incidence, degree and duration of hypercapnia during combined regional anaesthesia and monitored anaesthesia care in shoulder surgery patients

We studied the impact of transcutaneous continuous carbon dioxide tension (PtcCO2) monitoring on ventilation and oxygenation during monitored anaesthesia care (MAC) in patients scheduled for shoulder surgery with continuous interscalene block. 50 patients were randomised either to the intervention (I-group) or the control (C-group) group. In both groups MAC was performed using target controlled infusion of propofol and remifentanil. MAC regimen was adapted to PtcCO2 values in the I-group, whereas the C-group was blinded for these values. Primary outcome was the incidence, degree and duration of hypoventilation stages. In the I-group and the C-group the mean±SD [range] of PtcCO2 and PaCO2 was 5.79±0.84 [4.37] and 5.44±0.59 [2.78] kPa, as well as 6.41±1.17 [6.29] and 6.01±0.96 [7.15] kPa. Periods of PtcCO2/PaCO2>6.5kPa were 21.0±35.7/1.2±4.2min in the I-group and 45.6±40.0/18.6±26.8min in the C-group. Severe hypercapnia (PtcCO2 and/or PaCO2>7.5kPa) was dected in 3/0 patients of the I-group and in 10/3 patients of the C-group. PtcCO2 and PaCO2 showed a strong correlation (r=0.78), but only moderate agreement with a mean bias (LOA) of −0.37 (−1.69; +0.95) kPa showing an overestimation of the PaCO2. Sensitivity and specificity of PtcCO2 to detect changes of PaCO2 was 0.94 and 0.56, respectively. In no patient SpO2 or SaO2 values lower than 90% were measured. Despite a moderate agreement between PaCO2 and PtcCO2 the PtcCO2 monitoring significantly reduced incidence, degree and duration of hypercapnia in shoulder surgery patients with MAC

Accuracy of non-invasive continuous total hemoglobin measurement by Pulse CO-Oximetry in severe traumatized and surgical bleeding patients

The Masimo Radical-7 Pulse CO-Oximeter (Masimo Corp., USA) non-invasively computes hemoglobin concentration (SpHb). SpHb was compared to Co-Oximeter readings (CoOxHb) of arterial samples in surgery patients of the emergency department. Forty-six patients were enrolled. The Masimo R1 25L (revision F and G) adult adhesive sensor was attached to the ring finger of the arterially cannulated hand. Before start, every 30 min during surgery and in the case of severe bleeding SpHb and CoOxHb values were documented. SpHb and post hoc adjusted SpHb (AdSpHb) values were analyzed. Linear regression analysis and Bland-Altman plot for agreement were performed. The detection failure rate of SpHb was 24.5 %. CoOxHb and SpHb showed a strong correlation (r = +0.81), but agreement was moderate [bias (LOA) of -0.6 (-3.0; +1.9)] g/dl. Positive and negative predicted value was 0.49 and 0.69. Exclusion of changes of CoOxHb values ≤1 g/dl resulted in a positive and negative predictive value of 0.66 and 1.00. Post hoc adjustment of the SpHb (AdSpHb) improved linear correlation of CoOxHb and AdSpHb [r = +0.90 (p < 0.001)] but less the agreement [bias (LOA) of CoOxHb and AdSpHb = -0.1 (-2.1/+1.9) g/dl]. SpHb agreed only moderately with CoOxHb values and predicted decreases of CoOxHb only if changes of SpHb ≤ 1.0 g/dl were excluded. The detection failure rate of SpHb was high. At present, additional refinements of the current technology are necessary to further improve performance of non-invasive hemoglobin measurement in the clinical setting

In-vitro evaluation of the PediaSat continuous central venous oxygenation monitoring system

BACKGROUND AND OBJECTIVE: In-vitro performance of the PediaSat system for continuous monitoring of central venous oxygen saturation by spectrophotometry has been evaluated. METHODS: PediaSat continuous fibre-optic oximetry catheters were inserted in a black testing chamber, connected with an extracorporeal circuit and filled with human whole blood. Oxygen inflow into the cardiopulmonary bypass system was varied, and the testing chamber was perfused with blood flow of 1000 ml min. Oxygen saturation values measured by PediaSat (SPediaSatO2) were compared with cooximetry (SCO-OXO2) values from simultaneously taken blood samples by Bland-Altman and simple regression analyses. RESULTS: Fifty data pairs were obtained. SPediaSatO2 and SCO-OXO2 values ranged between 28-98 and 24.9-99.5%, respectively. Correlation between SPediSatO2 and SCO-OXO2 was high with an r value equal to 0.96 (P < 0.0001). Overall, SPediaSatO2 only slightly overestimated SCO-OXO2 (mean bias +2.9%), and limits of agreement (+/-2 SD of bias) were acceptable (-6.8/+12.6%). Sensitivity and specificity of the first differences of SPediaSatO2 and SCO-OXO2 were 1.0 and 0.92, respectively. Subgroup analysis of SCO-OXO2 values below 70% resulted in an overestimation by SPediaSatO2, with a mean bias of +5.2% and limits of agreement of -4.7 and +15.1%. CONCLUSION: The current version of the PediaSat system does not reliably reflect SCO-OXO2 values below 70%, but it seems to be a useful tool providing an accurate trend of continuous central venous oxygen saturation