Uncalibrated continuous cardiac output measurement in liver transplant patients: LiDCOrapid™ system versus pulmonary artery catheter.

OBJECTIVE: The aim of the study was to assess the level of agreement between continuous cardiac output estimated by uncalibrated pulse-power analysis (PulseCOLiR) and intermittent (ICO) and continuous cardiac output (CCO) obtained using a pulmonary artery catheter (PAC). DESIGN: Prospective cohort study. SETTING: University hospital intensive care unit. PARTICIPANTS: Twenty patients after liver transplantation. INTERVENTION: Pulmonary artery catheters were placed in all patients, and ICO and CCO were determined using thermodilution. PulseCOLiR measurements were made using a LiDCOrapid(TM) (LiDCO Ltd, Cambridge, UK). MEASUREMENTS AND MAIN RESULTS: ICO data were determined after intensive care unit admission and every 8 hours until the 48th postoperative hour. CCO and PulseCOLiR measurements were recorded simultaneously at these same time intervals as well as hourly. For the 8-hour data set (140 data pairs), the mean bias and percentage errors (PE) were, respectively,-0.10 L/min and 39.2% for ICO versus PulseCOLiR and 0.79 L/min and 34.6% for CCO versus PulseCOLiR. For the hourly comparison of CCO versus PulseCOLiR (980 data pairs), the bias was 0.75 L/min and the PE 37%. To assess the ability to measure change, a 4-quadrant plot was produced for each pair of methods. The performance of PulseCOLiR was moderate in detecting changes in ICO. CONCLUSIONS: In conclusion, the uncalibrated PulseCOLir method should not be used as a substitute for the thermodilution technique for the monitoring of cardiac output in liver transplant patients.

Effects of catecholamines on microcirculation during general inhalation anesthesia.

OBJECTIVE: The aim of this study was to investigate the effects of clinical dosages of norepinephrine and dobutamine on sublingual microcirculation during general anesthesia with sevoflurane in minor surgical procedures. DESIGN: This prospective study was performed on patients scheduled for breast cancer surgery. SETTING: Tertiary care university hospital. PARTICIPANTS: Twenty patients undergoing elective surgery. INTERVENTIONS: Patients received a continuous infusion of norepinephrine (0.1 µg/kg/min) and afterwards, following a 15-minute interval, a continuous infusion of dobutamine (5 µg/kg/min). Prior to and at the end of each drug infusion period, hemodynamic parameters were measured using an esophageal Doppler probe (ED), and 5 sidestream darkfield (SDF) sublingual microcirculation video recordings were taken. MEASUREMENTS AND MAIN RESULTS: No significant changes to total vessel density (TVD)(mm/mm(2)), perfused vessel density (PVD) (mm/mm(2)), proportion of perfused vessels (PPV) (percentage), or microvascular flow index (MFI) (arbitrary units) were measured at the end of each drug infusion period versus pre-infusion data and no differences were observed between the effects of norepinephrine versus dobutamine. Mean arterial pressure (APm) (mmHg) was significantly greater following both norepinephrine and dobutamine infusions compared to pre-infusion values, while peak velocity (PV) (cm/sec) and the stroke volume index (SVI) (mL/m(2)) only showed a significant increase following the dobutamine infusion. No change in corrected flow time (FTc) (msec) was observed. CONCLUSIONS: During general anesthesia with sevoflurane, the infusion of clinical dosages of norepinephrine and dobutamine did not alter sublingual perfusion, although the expected systemic hemodynamic alterations were induced.

Prognostic power of pre- and postoperative B-type natriuretic peptide levels in patients undergoing abdominal aortic surgery.

OBJECTIVES: The first aim of the present study was to evaluate the pre- and postoperative B-type natriuretic peptide (BNP) levels in patients undergoing surgery for repair of an infrarenal abdominal aortic aneurysm (AAA) and analyze their power as a predictor of in-hospital cardiac events. The second aim was to evaluate the association among pre- and postoperative BNP levels, postoperative patient complications, and length of hospital stay. DESIGN: Prospective observational study. SETTING: A university hospital. PARTICIPANTS: Forty-five patients undergoing elective surgery for an abdominal aortic aneurysm. INTERVENTIONS: The plasma BNP level was assessed just before surgery and then on postoperative day 1. Cardiac troponin I levels were measured postoperatively on arrival to the intensive care unit (time 0) and then 12, 48, and 72 hours later. MEASUREMENTS AND MAIN RESULTS: The preoperative BNP concentration in patients who developed an acute myocardial infarction was 209 (IQR 84-346) pg/mL compared with 74 (IQR 28-142) pg/mL in those who did not. The difference between groups was statistically significant (p = 0.04). The Spearman correlation showed that postoperative BNP levels correlated significantly with preoperative BNP levels (r = 0.73, p = 0.0001), length of hospital stay (r = 0.35, p = 0.04), and troponin I concentration at 0 hour (r = 0.42, p = 0.02), 12 hours (r = 0.51, p = 0.0052), and 48 hours (r = 0.40, p = 0.033). In contrast, preoperative BNP levels correlated with troponin I at only 12 hours (r = 0.34, p = 0.02). Postoperative BNP levels were influenced significantly by transfusions (p = 0.035) and cross-clamping times (p = 0.038). CONCLUSIONS: The present results confirm the high negative predictive value of preoperative BNP levels; and postoperative BNP levels showed a better correlation with postoperative troponin levels, blood transfusion, and postoperative cardiac events.

Uncalibrated arterial pulse cardiac output measurements in patients with moderately abnormal left ventricular function.

OBJECTIVE: The aim of the study was to evaluate the accuracy and precision of the Vigileo/FloTrac system (Edwards Lifesciences, Irvine, CA) when compared with the intermittent cardiac output and continuous cardiac output measurements obtained from pulmonary arterial catheters in patients with moderately abnormal left ventricular function undergoing elective coronary artery bypass graft surgery. DESIGN: A prospective, observational study. SETTING: Tertiary university hospital. PARTICIPANTS: Twenty patients with moderately abnormal left ventricular function undergoing coronary artery bypass graft surgery were enrolled. MEASUREMENTS AND RESULTS: Data were collected before the induction of anesthesia (T1), after the induction of anesthesia (T2), before cardiopulmonary bypass with an open chest (T3), after cardiopulmonary bypass (T4), after sternal closure (T5), on intensive care unit admission (T6), and at 6 hours (T7) and 12 hours after surgery (T8). A total of 360 data measurements were collected; the mean bias between intermittent cardiac output (ICO) and arterial pressure cardiac output (APCO) was -0.50 ± 1.72 L/min, and the percentage error (PE) was 37.00%. The mean difference between CCO and APCO was -0.06 ± 1.84 L/min, and the PE was 37.80%. The correlation between ΔICO and ΔAPCO was r = 0.7; the correlation between ΔCCO and ΔAPCO was r = 0.73. In the intraoperative period, the mean bias between ICO and APCO was -0.41 ± 1.75 L/min, and the PE was 40.87%. The mean difference between CCO and APCO was -0.18 ± 1.90 L/min, and the PE was 41.48%. In the postoperative period, the mean bias between ICO and APCO was -0.56 ± 1.70 L/min, and the PE was 34.43%. The mean difference between CCO and APCO was -0.36 ± 1.76 L/min, and the PE was 34.87%. CONCLUSIONS: In cardiac surgical patients with moderately abnormal left ventricular function, the Vigileo/FloTrac 2nd generation software sensor device showed mild intraoperative and postoperative agreement when compared with a pulmonary arterial catheter.

Continuous and intermittent cardiac output measurement in hyperdynamic conditions: pulmonary artery catheter vs. lithium dilution technique.

OBJECTIVE: This study aimed to assess the level of agreement of both intermittent cardiac output monitoring by the lithium dilution technique (CO(Li)) and continuous cardiac output monitoring (PulseCO(Li)) using the arterial pressure waveform with intermittent thermodilution using a pulmonary artery catheter (CO(PAC)). DESIGN: Prospective, single-center evaluation. SETTING: University Hospital Intensive Care Unit. PATIENTS: Patients (n=23) receiving liver transplantation. INTERVENTION: Pulmonary artery catheters were placed in all patients and CO(PAC) was determined using thermodilution. CO(Li) and PulseCO(Li) measurements were made using the LiDCO system. MEASUREMENTS AND MAIN RESULTS: Data were collected after intensive care unit admission and every 8h until the 48th hour. A total of 151 CO(PAC), CO(Li) and PulseCO(Li) measurements were analysed. Bias and 95% limit of agreement were 0.11lmin(-1) and -1.84 to + 2.05 lmin(-1) for CO(PAC) vs. CO(Li) (r=0.88) resulting in an overall percentage error of 15.6%. Bias and 95% limit of agreement for CO(PAC) vs. PulseCO(Li) were 0.29 lmin(-1) and -1.87 to + 2.46 lmin(-1) (r=0.85) with a percentage error of 16.8%. Subgroup analysis revealed a percentage error of 15.7% for CO(PAC) vs. CO(Li) and 15.1% for CO(PAC) vs. PulseCO(Li) for data pairs less than 8 lmin(-1), and percentage errors of 15.5% and 18.5% respectively for data pairs higher than 8 lmin(-1). CONCLUSION: In patients with hyperdynamic circulation, intermittent and continuous CO values determined using the LiDCO system showed good agreement with those obtained by intermittent pulmonary artery thermodilution.

Arterial pulse cardiac output agreement with thermodilution in patients in hyperdynamic conditions.

OBJECTIVE: This study aimed to compare continuous cardiac output (CCO) obtained using the arterial pulse wave (APCO) measurement with a simultaneous measurement of the intermittent cardiac output (ICO) and CCO obtained with a pulmonary artery catheter (PAC) in liver transplant patients. DESIGN: A prospective, single-center evaluation. SETTING: A university hospital intensive care unit. PATIENTS: Eighteen patients after liver transplantation. INTERVENTIONS: Pulmonary artery catheters were placed in all patients, and ICO and CCO were determined using thermodilution. APCO measurements were made with the Vigileo System (Edwards Lifesciences, Irvine, CA). MEASUREMENTS AND MAIN RESULTS: The authors obtained 126 data pairs of ICO and APCO and 864 pairs of CCO and APCO. ICO data were collected after intensive care unit admission and every 8 hours until the 48th postoperative hour. CCO and APCO data were collected every hour from admission until the 48th postoperative hour. Bias and precision were 0.95 +/- 1.41 L/min for ICO versus APCO and 1.29 +/- 1.28 L/min for CCO and APCO. Bias and precision for cardiac output (CO) data pairs less than 8 L/min were 0.32 +/- 1.14 L/min between ICO and APCO and 0.71 +/- 0.98 L/min between CCO and APCO. For CO data pairs higher than 8 L/min, bias and precision were 1.79 +/- 1.54 L/min between ICO and APCO and 2.25 +/- 1.14 L/min between CCO and APCO. CONCLUSIONS: APCO enables the assessment of CO with clinically acceptable bias and precision. At higher CO levels, APCO underestimates PAC measurements and it is not as reliable as thermodilution in hyperdynamic liver transplant patients.

Analgesia in PACU: nonsteroidal anti-inflammatory drugs.

Control and abolition of pain during and after surgical procedures is crucial point in the practice of anaesthesiology. In the last years the concept of multimodal analgesia (the use of different analgesic and techniques to relieve pain), has developed and non-steroidal anti-inflammatory drugs (NSAIDs) have a major role in it, because they have an opioid sparing effect. Moreover, they are very effective on somatic and breakthrough pain. NSAIDs can be divided functionally in four classes: salicylates, acetaminophen, non-specific inhibitors (i.e. ibuprofen, ketorolac, etc.) and cyclooxygenase2-inhibitors (coxibs). The target of action of these drugs is the different isozymes of the Prostaglandin G/H synthase, called Cyclooxygenases (COX). At least three different types of COX have been identified, which are probably organ specific. These isozymes play a crucial role in the developing of the inflammatory cascade, and in the genesis of various pain mediators released from tissue injury. Their most important side effects affect mainly gastrointestinal system, the kidney and the coagulation system. Less important are the effects on the liver and the immunologic system (asthma). The analgesic nephropathy and the coagulopathy must be taken into account in the surgical patient, for the possibility of increase perioperative morbidity. Very recently the newest class of coxibs, although they reduce g.i. bleeding and coagulopathy, have proved to increase the risk of cardiovascular accidents both in long term therapy than postoperatively in cardiac surgical patients. Many data are needed, but in patients at high risk of cardiac disease other NSAIDs should be considered.

The dos and do knots of central venous catheterization.

Central venous catheterization plays an important role in patients with end-stage renal disease undergoing hemodialysis. Placement of a right subclavian hemodialysis catheter was complicated by looping and entrapment of the guidewire. Computed tomographic and three-dimensional scans were essential in locating and determining that the guidewire was outside the vessel.