Pulse Contour Cardiac Output Measurements Research Articles

A model of porcine polymicrobial septic shock

BackgroundSepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Mortality of patients with sepsis is high and largely unchanged throughout the past decades. Animal models have been widely used for the study of sepsis and septic shock, but translation into effective treatment regimes in the clinic have mostly failed. Pigs are considered as suitable research models for human diseases due to their high comparability and similarity to human anatomy, genetics, and the immune system. We here evaluated the previously reported models of septic shock in pigs and established a novel model of polymicrobial sepsis that meets the clinical criteria of septic shock in pigs.Materials and methodsThe literature search was performed using the keywords “pig”, “sepsis” and “septic shock”. For the establishment of septic shock in n = 10 German landrace pigs, mechanical ventilation was initiated, central venous and arterial lines and invasive hemodynamic monitoring via pulse contour cardiac output measurement (PiCCO) established. Peritoneal polymicrobial faecal sepsis was induced by application of 3 g/kg body weight faeces into the abdominal cavity. Septic shock was defined according to the third international consensus definitions (Sepsis-3). Upon shock, pigs underwent the 1-h bundle for the treatment of human sepsis. Cytokine levels were measured by ELISA.ResultsPublished porcine sepsis models exhibited high methodological variability and did not meet the clinical criteria of septic shock. In our model, septic shock developed after an average of 4.8 ± 0.29 h and was associated with a reproducible drop in blood pressure (mean arterial pressure 54 ± 1 mmHg) and significant hyperlactatemia (3.76 ± 0.65 mmol/L). Septic shock was associated with elevated levels of interleukin-6 (IL6) and initial cardiac depression followed by a hyperdynamic phase with significant loss of systemic vascular resistance index after initial resuscitation. In addition, organ dysfunction (acute kidney injury) occurred.ConclusionsWe here established a model of septic shock in pigs that meets the clinical criteria of septic shock utilized in human patients. Our model may thus serve as a reference for clinically relevant sepsis research in pigs.

A quantitative CT parameter for the assessment of pulmonary oedema in patients with acute respiratory distress syndrome.

ObjectivesThe aim of this study was to establish quantitative CT (qCT) parameters for pathophysiological understanding and clinical use in patients with acute respiratory distress syndrome (ARDS). The most promising parameter is introduced.Materials and methods28 intubated patients with ARDS obtained a conventional CT scan in end-expiratory breathhold within the first 48 hours after admission to intensive care unit (ICU). Following manual segmentation, 137 volume- and lung weight-associated qCT parameters were correlated with 71 clinical parameters such as blood gases, applied ventilation pressures, pulse contour cardiac output measurements and established status and prognosis scores (SOFA, SAPS II).ResultsOf all examined qCT parameters, excess lung weight (ELW), i.e. the difference between a patient’s current lung weight and the virtual lung weight of a healthy person at the same height, displayed the most significant results.ELW correlated significantly with the amount of inflated lung tissue [%] (p<0.0001; r = -0.66) and was closely associated with the amount of extravascular lung water (EVLW) (p<0.0001; r = 0.72). More substantially than the oxygenation index (PaO2/FiO2) or any other clinical parameter it correlated with the patients’ mean SOFA- (p<0.0001, r = 0.69) and SAPS II-Score (p = 0.0005, r = 0.62). Patients who did not survive intensive care treatment displayed higher values of ELW in the initial CT scans.ConclusionsELW could serve as a non-invasive method to quantify the amount of pulmonary oedema. It might serve as an early radiological marker of severity in patients with ARDS.

Hemodynamic effects of low-dose bupivacaine spinal anesthesia for cesarean section: A randomized controlled trial.

Background:Spinal anesthesia is the most common technique for cesarean section. The conventional local anesthetic dose has been decreasing over time to 8–12.5 mg of bupivacaine. Lower doses of bupivacaine may be associated with reduced incidence of hypotension and other complications. This low dose also may be associated with improved maternal cardiac index (CI). We hypothesized that low dose spinal anesthesia using 4.5 mg bupivacaine would result in improved maternal CI when compared with conventional dose (9 mg) intrathecal bupivacaine.Methods:This randomized controlled trial included all healthy parturients presenting for elective cesarean section. In addition to standard monitors, an arterial line was placed for pulse contour cardiac output measurement. Due to limited data on maternal cardiac output during cesarean section, we had to power our study on recovery room length of stay. Secondary outcomes included the change in maternal CI, fluid administration, vasopressor usage, maternal satisfaction, and adequacy of surgical blockade and recovery time from motor and sensory blockade.Results:The low dose group had significantly faster motor recovery times (132 [122–144] versus. 54 [48–66] min conventional versus. low-dose, respectively, P < 0.01), and a shorter recovery room stay (92 ± 21 vs 70 ± 11 min, conventional vs. low-dose, respectively, P < 0.01, 95% CI -35 to -10 min). There was no difference in CI between the conventional dose and low dose spinal groups. Both groups had a drop in CI with spinal anesthesia. The low-dose group demonstrated equivalent surgical anesthesia and block onset times compared to the conventional group.Conclusions:Low-dose spinal anesthesia provides adequate surgical anesthesia, improved recovery time, but no difference in maternal cardiac index when compared to conventional dose spinal anesthesia.NCT02046697

Trending ability and limitations of transpulmonary thermodilution and pulse contour cardiac output measurement in cats as a model for pediatric patients.

The present study evaluated transpulmonary thermodilution (TPTD) and pulse contour cardiac output (PCCO) both measured by the PiCCO Plus™ monitor (Pulsion Medical Systems, Munich, Germany) against pulmonary artery thermodilution (PATD) in cats as a hemodynamic model for small children. A wide range of cardiac outputs (CO) was simultaneously measured. Accuracy and trending abilities were critically evaluated. Three cats were studied under isoflurane anesthesia and 160 CO measurements were performed with 3 mL ice-cold 5 % dextrose with PATD and TPTD. The results were compared with the PCCO measurement before the bolus measurement. Cardiac output was manipulated from 32 to 224 mL/kg/min by dobutamine, dopamine, phenylephrine, medetomidine and increased concentrations of isoflurane. Bland-Altman analysis, concordance and polar plot analysis were performed to assess accuracy and trending ability. TPTD was measuring constantly higher than PATD with a mean bias of 73 mL/kg/min and limits of agreement of 34-112 mL/kg/min, a concordance rate of 94 % and a mean polar angle of -5° with radial limits of agreement (RLOA) of 33°. Concordance rate of the PCCO versus PATD was 82 % with a mean polar angle of -10° and RLOA of 46° and versus TPTD 90 % with a mean polar angle of -6° and RLOA of 46°. Both tested methods constantly overestimated simultaneous PATD measurements. The small size, low flows and the relative short catheter not reaching the abdominal aorta may explain that. However TPTD tracked changes accurately opposed to a poor trending ability of the PCCO measurement.

Effect of time elapsed on continuous pulse contour cardiac output measurement in septic shock patients

To evaluate the effect of time elapsed on continuous pulse contour cardiac output (PCCO) measurement in septic shock patients. Data during February 2011 to February 2013 from 25 septic shock patients equipped with a pulse indicator continuous cardiac output (PiCCO) device in Department of Critical Care Medicine of Guangzhou Medical University were retrospectively analyzed. PCCO was recorded immediately before transpulmonary thermodilution (COTPTD) calibration. After divided by ideal body surface area, cardiac index (CI) was calculated, and PCCI/CITPTD pairs were analyzed. Four subsets of CI pairs were defined according to intervals of time elapsed from the previous calibration [within the first hour (including 1 hour), between 1 and 8 hours (including 8 hours), between 8 and 16 hours (including 16 hours), and more than 16 hours]. Linear regression, the threshold value of concordance (as indicated by bias ± 2SD) and percentage error (2SD/the mean of CITPTD) were used to compare agreement between PCCI and CITPTD. A total of 162 data pairs from 25 patients were analyzed. For all data pairs, PCCI correlated significantly with CITPTD (r² = 0.494, P<0.001), the bias±2SD was -(0.06 ± 1.41) L × min⁻¹ × m⁻² and the percentage error was 37%. Among the four time-interval subsets, the percentage error was <30% only in subset between 1 and 8 hours, and the percentage error in other subsets was over 30%. Linear regression analysis between ΔPCCI and ΔCITPTD showed a r² of 0.217 (P<0.001) for the whole 162 data pairs. A r² of 0.327 (P<0.001) and a r² of 0.303 (P<0.001) were calculated for the subset of between 1 and 8 hours and between 8 and 16 hours respectively. Our study in septic shock patients suggests that the accuracy of PCCO will be decreased as the increase of the time interval for calibration. Transpulmonary thermodilution calibration should be performed again if hemodynamic changes or was inconsistent with the clinical presentation. It is suggested that re-calibration should be done within 8 hours.

Pulse contour cardiac output analysis in a piglet model of severe hemorrhagic shock*

Pulse contour cardiac output (PCCO) analysis is a technique for continuous cardiac output (CO) monitoring through an arterial catheter after calibration by transpulmonary thermodilution (TPTD). Studies in adults show good correlation with pulmonary artery thermodilution (PATD) CO. Data are limited in children and patients with hemodynamic instability. The objective was to determine whether TPTD CO and PCCO analysis correlate with PATD CO in a piglet model of severe hemorrhagic shock. Mixed venous oxygen saturation (SVO2) was also compared with PATD CO. Prospective animal study. University animal research laboratory. Domesticated piglets, 24-37 kg. Hemorrhagic shock was created by graded hemorrhage in anesthetized piglets. Hemorrhage was initiated to achieve mean arterial pressure plateaus of 60, 50, 40, 30, and 20 mm Hg. CO was measured by PATD and simultaneously with two femoral artery PCCO catheters. At each mean arterial pressure plateau, one PCCO catheter was recalibrated by TPTD; the other catheter was not recalibrated during hemorrhage. TPTD CO, PCCO measurements from each catheter, and SVO2 were compared with PATD CO at each mean arterial pressure level. TPTD CO and recalibrated PCCO showed excellent correlation (r2 = .96 and .97) and small bias (+0.11 and +0.14 L/min), respectively, compared with PATD. Without recalibration, PCCO measurements were not accurate during rapid hemorrhage (r2 = .22). SVO2 decline did not correlate as well with PATD CO (r2 = .69). TPTD CO and recalibrated PCCO analysis correlate well with PATD CO in this severe hemorrhagic shock model. The mean difference is small (<0.15 L/min) and is not clinically significant. With rapid changes in blood pressure or intravascular volume, PCCO is not accurate unless recalibrated by TPTD CO. SVO2 did not correlate well with CO in this model.

Reliability of continuous pulse contour cardiac output measurement

To evaluate the reliability of continuous cardiac output monitoring using pulse-contour analysis in critically ill patients.

Reliability of Continuous Pulse Contour Cardiac Output Measurement during Hemodynamic Instability

Arterial pulse contour analysis is gaining widespread acceptance as a monitor of continuous cardiac output (CO). While this type of CO measurement is thought to provide acceptable continuous measurements, only a few studies have tested its accuracy and repeatability under unstable hemodynamic conditions. We compared continuous CO measurement using the pulse contour method (PCCO) before and after calibration with intermittent transpulmonary thermodilution cardiac output (TpCO). We compared the two methods of CO measurements in 15 Landrace pigs weighing 20-25 kg in an experimental model of sepsis. Nine pigs were given an infusion of E. coli lipopolysacchride (LPS), and six pigs acted as controls. PCCO values before and after calibration (PCCO1 and PCCO2 respectively) were registered, and their errors relative to TpCO measurements were compared. The mean coefficient of variation for repeated PCCO measurements was 6.85% for the control group, and 13.99% for the endotoxin group. The range of TpCO was 1.01-3.15 L/min. In the control group the bias +/-2SD was 0.11 +/- 0.53 L/min (TpCO vs PCCO1) and -0.02 +/- 0.38 L/min (TpCO vs PCCO2). In the endotoxin group, the agreement was poor between TpCO and PCCO1, 0.08 +/- 1.02 L/min. This improved after calibration (TpCO vs PCCO2) to 0.01 +/- 0.31 L/min. In hemodynamically stable pigs, both pre- and post-calibration PCCO measurements agreed well with the intermittent transpulmonary thermodilution technique. However, during hemodynamic instability, and pre-calibration PCCO values had wide limits of agreement compared with TpCO. This was reflected by larger coefficients of variation for PCCO in hemodynamic instability. The error of PCCO measurement improved markedly after calibration, with bias and limits of agreement within clinically acceptable limits.

Pulse contour cardiac output in surgical intensive care unit patients

Study Objective: To evaluate the ability of arterial waveform contour analysis to measure cardiac output (CO) continuously in postoperative critically ill patients. Design: Thermodilution CO (TDCO) measurements were compared with simultaneous pulse contour CO (PCCO) measurements. Setting: University hospital surgical intensive care unit. Patients: 29 critically ill surgical patients with indwelling systemic arterial and pulmonary artery catheters. Measurements and Main Results: TDCO measurements were compared with PCCO at 1- to 2-hour intervals. Mean TDCO was 5.75 ± 1.79 L/min, and mean PCCO was 5.76 ± 1.83 L/min. Analysis of the difference between TDCO and PCCO showed a bias of 0.01 ± 0.5 L/min. Comparison of the difference between pairs of sequential TDCO measurements and the initial TDCO and subsequent PCCO measurements resulted in a correlation coefficient of 0.64. Conclusions: The PCCO method appears to be able to estimate changes in CO under the conditions tested, in which PCCO was recalibrated after each TDCO measurement. However, limitations of this method in the immediate postoperative period following aortic aneurysm surgery were identified.