Continuously assessed right ventricular end-diastolic volume as a marker of cardiac preload and fluid responsiveness in mechanically ventilated cardiac surgical patients

INTRODUCTION: Assessing cardiac preload and fluid responsiveness accurately is important when attempting to avoid unnecessary volume replacement in the critically ill patient, which is associated with increased morbidity and mortality. The present clinical trial was designed to compare the reliability of continuous right ventricular end-diastolic volume (CEDV) index assessment based on rapid response thermistor technique, cardiac filling pressures (central venous pressure [CVP] and pulmonary capillary wedge pressure [PCWP]), and transesophageal echocardiographically derived evaluation of left ventricular end-diastolic area (LVEDA) index in predicting the hemodynamic response to volume replacement. METHODS: We studied 21 patients undergoing elective coronary artery bypass grafting. After induction of anesthesia, hemodynamic parameters were measured simultaneously before (T1) and 12 min after volume replacement (T2) by infusion of 6% hydroxyethyl starch 200/0.5 (7 ml/kg) at a rate of 1 ml/kg per min. RESULTS: The volume-induced increase in thermodilution-derived stroke volume index (SVI(TD)) was 10% or greater in 19 patients and under 10% in two. There was a significant correlation between changes in CEDV index and changes in SVI(TD )(r(2 )= 0.55; P < 0.01), but there were no significant correlations between changes in CVP, PCWP and LVEDA index, and changes in SVI(TD). The only variable apparently indicating fluid responsiveness was LVEDA index, the baseline value of which was weakly correlated with percentage change in SVI(TD )(r(2 )= 0.38; P < 0.01). CONCLUSION: An increased cardiac preload is more reliably reflected by CEDV index than by CVP, PCWP, or LVEDA index in this setting of preoperative cardiac surgery, but CEDV index did not reflect fluid responsiveness. The response of SVI(TD )following fluid administration was better predicted by LVEDA index than by CEDV index, CVP, or PCWP

The predictive value of the Pleth Variability Index on fluid responsiveness in spontaneously breathing anaesthetized children—A prospective observational study

Background: In children, the preoperative hydration status is an important part of the overall clinical assessment. The assumed preoperative fluid deficit is often routinely replaced during induction without knowing the child's actual fluid status. Aim: We investigated the predictive value of the Pleth Variability Index as a measure of fluid responsiveness in spontaneously breathing anesthetized children. Methods: Pleth Variability Index, stroke volume and Cardiac Index, measured by electrovelocimetry, mean blood pressure, and heart rate were recorded during anesthesia induction in 50 pediatric patients 15% (Positive predictive value 2.71 (95% CI: 1.4 to 5.2)). Only in fluid responders, the Pleth Variability Index decreased during passive leg raising, while stroke volume increased. Conclusions: The Pleth Variability Index may be of additional value to predict fluid responsiveness in spontaneously breathing anesthetized children. A significant overlap in baseline Pleth Variability Index values between fluid responsive and nonfluid responsive patients does not allow a reliable recommendation as to a cut off value

The effects of midazolam on intraocular pressure in children during examination under sedation

Background: To obtain reliable and accurate measurements of the intraocular pressure (IOP) in children often requires sedation or anaesthesia. Therefore, we investigated the effects of oral midazolam on IOP in children. Methods: In a prospective study, IOP was measured in 72 eyes of 36 cooperative children without glaucoma requiring general anaesthesia (mean age 3.5±1.3 years, body weight ≤20 kg) by using a Perkins hand-held tonometer. Measurements of IOP were performed before, and 15 and 30 min after sedation with orally administered midazolam (1 mg/kg) given as preoperative medication, and 5 and 15 min after induction of general anaesthesia. The individual IOP courses were analysed. Results: In all of the cooperative children, IOP measurement was possible after sedation with midazolam. Mean IOP was 11.2±0.3 mmHg before sedation, 10.9±0.2 mmHg at 15 min, and 10.7±0.3 mmHg 30 min after administration of midazolam. This small decrease was not statistically significant, whilst the IOP decline at 5 and 15 min after induction of general anaesthesia was statistically significant (p<0.0001). Conclusion: Sedation with midazolam can be assumed to be an applicable, well-tolerated, safe method for IOP measurements in children

Pronounced haemodynamic changes during and after robotic-assisted laparoscopic prostatectomy: a prospective observational study

Objectives Robotic-assisted laparoscopic prostatectomy (RALP) is typically conducted in steep Trendelenburg position (STP). This study investigated the influence of permanent 45 degrees STP and capnoperitoneum on haemodynamic parameters during and after RALP. Design Prospective observational study. Setting Haemodynamic changes were recorded with transpulmonary thermodilution and pulse contour analysis in men undergoing RALP under standardised anaesthesia. Participants Informed consent was obtained from 51 patients scheduled for elective RALP in a University Medical Centre in Germany. Interventions Heart rate, mean arterial pressure, central venous pressure (CVP), Cardiac Index (CI), systemic vascular resistance (SVR), Global End-Diastolic Volume Index (GEDI), global ejection fraction (GEF), Cardiac Power Index (CPI) and stroke volume variation (SVV) were recorded at six time points: 20 min after induction of anaesthesia (T1), after insufflation of capnoperitoneum in supine position (T2), after 30 min in STP (T3), when controlling Santorini's plexus in STP (T4), before awakening in supine position (T5) and after 45 min in the recovery room (T6). Adverse cardiac events were registered intraoperatively and postoperatively. Results All haemodynamic parameters were significantly changed by capnoperitoneum and STP during RALP and partly normalised at T6. CI, GEF and CPI were highest at T6 (CI: 3.9 vs 2.2 L/min/m(2); GEF: 26 vs 22%; CPI: 0.80 vs 0.39 W/m(2); p<0.001). CVP was highest at T4 (31 vs 7 mm Hg, p<0.001) and GEDI at T6 (819 vs 724 mL/m(2), p=0.005). Mean SVR initially increased (T2) but had decreased by 24% at T6 (p<0.001). SVV was highest at T5 (12 vs 9%, p<0.001). Two of the patients developed cardiac arrhythmia during RALP and one patient suffered postoperative cardiac ischaemia. Conclusions RALP led to pronounced perioperative haemodynamic changes. The combination of increased cardiac contractility and heart rate reflects a hyperdynamic situation during and after RALP. Anaesthesiologists should be aware of unnoticed pre-existing heart failure to worsen during STP in patients undergoing RALP

Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration

<p>Abstract</p> <p>Background</p> <p>Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (CO_PAC) measurement by the pulmonary artery catheter (PAC). However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (CO_AP) device (FloTrac™, Vigileo™; Edwards Lifesciences, Irvine, CA, USA) only requires access to the radial or femoral artery using a standard arterial catheter and does not need an external calibration. We validated this technique in critically ill patients in the intensive care unit (ICU) using CO_PACas the method of reference.</p> <p>Methods</p> <p>We studied 20 critically ill patients, aged 16 to 74 years (mean, 55.5 ± 18.8 years), who required both arterial and pulmonary artery pressure monitoring. CO_PACmeasurements were performed at least every 4 hours and calculated as the average of 3 measurements, while CO_APvalues were taken immediately at the end of bolus determinations. Accuracy of measurements was assessed by calculating the bias and limits of agreement using the method described by Bland and Altman.</p> <p>Results</p> <p>A total of 164 coupled measurements were obtained. Absolute values of CO_PACranged from 2.80 to 10.80 l/min (mean 5.93 ± 1.55 l/min). The bias and limits of agreement between CO_PACand CO_APfor unequal numbers of replicates was 0.02 ± 2.92 l/min. The percentage error between CO_PACand CO_APwas 49.3%. The bias between percentage changes in CO_PAC(ΔCO_PAC) and percentage changes in CO_AP(ΔCO_AP) for consecutive measurements was -0.70% ± 32.28%. CO_PACand CO_APshowed a Pearson correlation coefficient of 0.58 (<it>p </it>< 0.01), while the correlation coefficient between ΔCO_PACand ΔCO_APwas 0.46 (<it>p </it>< 0.01).</p> <p>Conclusion</p> <p>Although the CO_APalgorithm shows a minimal bias with CO_PACover a wide range of values in an inhomogeneous group of critically ill patients, the scattering of the data remains relative wide. Therefore, the used algorithm (V 1.03) failed to demonstrate an acceptable accuracy in comparison to the clinical standard of cardiac output determination.</p

Investigating propofol-sufentanil interaction using clinical endpoints and processed electroencephalography: a prospective randomized controlled trial

BACKGROUND: Propofol and sufentanil target controlled infusion technology is used with increasing frequency. Drug interaction modelling, using clinical endpoints and processed electroencephalography helps determine optimal drug concentrations to assure adequate anesthesia. METHODS: Sixty patients were randomized to receive a constant concentration of sufentanil (0.25 ng/mL (Group S-0.25), 0.5 ng/mL (Group S-0.5), 0 ng/mL (Group S-0). Propofol was administered in steps of 0.5 mu g/mL, up to 4 mu g/mL. Processed EEG (Bispectral Index, Narcotrend Index) and auditory evoked potentials (composite A-Line autoregressive Index; cAAI), were recorded simultaneously. Sufentanil-propofol interaction was assessed by Probit - and nonlinear regression analysis. RESULTS : Sufentanil had a dose-dependent synergistic effect on the effect-site concentration of propofol (mu g/mL) associated with a 50% probability (EC50) of loss of responsiveness to verbal command (S-0: 2.84 mu g/mL, R-2 0.773; S-0.25: 1.95 mu g/mL, R-2 0.862; S-0.5: 1.48 mu g/mL, R-2 0.887) and noxious stimulation (S-0: 3.46 mu g/mL, R-2 0.626 mu g/mL; S-0.25: 2.17 mu g/mL, R-2 0.853; S-0.5: 1.69 mu g/mL, R-2 0.897). Non-linear regression analysis revealed a synergistic sufentanil effect on the propofol EC50 for BIS (S-0: 3.36 mu g/mL, R-2 0.79; S-0.25: 2.77 mu g/mL, R-2 0.86 mu g/mL; S-0.5: 2.6 mu g/mL, R-2 0.84), Narcotrend Index (S-0: 3.57 mu g/mL, R-2 0.66; S-0.25: 2.91 mu g/mL, R-2 0.70; S-0.5: 2.02 mu g/mL, R-2 0.51) and cAAI (S-0: 3.42 mu g/mL, R-2 0.59; S-0.25: 3.00 mu g/mL, R-2 0.63; S-0.5: 3.14 mu g/mL, R-2 0.59). CONCLUSIONS: Sufentanil has a synergistic effect on the clinically observed hypnotic properties of propofol. These findings apply also to the depth of hypnosis measured by the Bispectral Index, Narcotrend Index and cAAI

Effect of Hydroxyethyl Starch Solution on Incidence of Acute Kidney Injury in Patients Suffering from Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage

The application of third-generation hydroxyethyl starch (HES) solutions in critically ill patients suffering from aneurysmal subarachnoid hemorrhage (aSAH) was often part of the treatment of delayed cerebral ischemia (DCI). However, there is increasing evidence showing a correlation between the application of HES and the incidence of acute kidney injury (AKI). In a single-center retrospective analysis including 81 patients without a preexisting renal disorder suffering from aSAH who had received higher volumes of 6 % HES 130/0.4 due to standard treatment of DCI, the incidence of AKI during intensive care unit (ICU) stay was recorded using AKIN criteria. Furthermore, the course of serum creatinine after discharge from ICU was observed. 6 % HES 130/0.4 was given over a period of 12.9 +/- 7.1 days resulting in a cumulative dose of 12543.2 +/- 7743.6 mL. Four patients (4.9 %) fulfilled AKIN criteria stage 1 during ICU stay. In two of these patients, serum creatinine was within normal range again on day of discharge. Five patients showed elevated levels of serum creatinine within 1 to 22 months after hospitalization. A correlation between the amount of HES given and the incidence of AKI could not be found. The application of 6 % HES 130/0.4 did not lead to an elevated incidence of AKI in patients without an elevated baseline serum creatinine. However, there is still a lack of high-level evidence as prospective randomized trials are missing yet

A new pumpless extracorporeal interventional lung assist in critical hypoxemia/hypercapnia

OBJECTIVE: Pump-driven extracorporeal gas exchange systems have been advocated in patients suffering from severe acute respiratory distress syndrome who are at risk for life-threatening hypoxemia and/or hypercapnia. This requires extended technical and staff support. DESIGN: We report retrospectively our experience with a new pumpless extracorporeal interventional lung assist (iLA) establishing an arteriovenous shunt as the driving pressure. SETTING: University hospital. PATIENTS: Ninety patients with acute respiratory distress syndrome. INTERVENTIONS: Interventional lung assist was inserted in 90 patients with acute respiratory distress syndrome. MEASUREMENTS AND MAIN RESULTS: Oxygenation improvement, carbon dioxide elimination, hemodynamic variables, and the amount of vasopressor substitution were reported before, 2 hrs after, and 24 hrs after implementation of the system. Interventional lung assist led to an acute and moderate increase in arterial oxygenation (Pao2/Fio2 ratio 2 hrs after initiation of iLA [median and interquartile range], 82 mm Hg [64-103]) compared with pre-iLA (58 mm Hg [47-78], p < .05). Oxygenation continued to improve for 24 hrs after implementation (101 mm Hg [74-142], p < .05). Hypercapnia was promptly and markedly reversed by iLA within 2 hrs (Paco2, 36 mm Hg [30-44]) in comparison with before (60 mm Hg [48-80], p < .05], which allowed a less aggressive ventilation. For hemodynamic stability, all patients received continuous norepinephrine infusion. The incidence of complications was 24.4%, mostly due to ischemia in a lower limb. Thirty-seven of 90 patients survived, creating a lower mortality rate than expected from the Sequential Organ Failure Assessment score. CONCLUSIONS: Interventional lung assist might provide a sufficient rescue measure with easy handling properties and low cost in patients with severe acute respiratory distress syndrome and persistent hypoxia/hypercapnia