Echocardiography and pulse contour analysis to assess cardiac output in trauma patients.

BACKGROUND: Echocardiography is a valuable technique to assess cardiac output (CO) in trauma patients, but it does not allow a continuous bedside monitoring. Beat-to-beat CO assessment can be obtained by other techniques, including the pulse contour method MostCare. The aim of our study was to compare CO obtained with MostCare (MC-CO) with CO estimated by transthoracic echocardiography (TTE-CO) in trauma patients. METHODS: Forty-nine patients with blunt trauma admitted to an intensive care unit and requiring hemodynamic optimization within 24 hours from admission were studied. TTE-CO and MC-CO were estimated simultaneously at baseline, after a fluid challenge and after the start of vasoactive drug therapy. RESULTS: One hundred sixteen paired CO values were obtained. TTE-CO values ranged from 2.9 to 7.6 L·min(-1), and MC-CO ranged from 2.8 to 8.2 L·min(-1). The correlation between the two methods was 0.94 (95% confidence interval [CI]=0.89 to 0.97; P<0.001). The mean bias was -0.06 L·min(-1) with limits of agreements (LoA) of -0.94 to 0.82 L·min(-1) (lower 95% CI, -1.16 to -0.72; upper 95% CI, 0.60 to 1.04) and a percentage error of 18%. Changes in CO showed a correlation of 0.91 (95% CI=0.87 to 0.95; P<0.001), a mean bias of -0.01 L·min(-1) with LoA of -0.67 to 0.65 L·min(-1) (lower 95% CI, -0.83 to -0.51; upper 95% CI, 0.48 to 0.81). CONCLUSION: CO measured by MostCare showed good agreement with CO obtained by transthoracic echocardiography. Pulse contour analysis can complement echocardiography in evaluating hemodynamics in trauma patients.

Comparison between an uncalibrated pulse contour method and thermodilution technique for cardiac output estimation in septic patients.

BACKGROUND: The purpose of this study was to evaluate the reliability of a new uncalibrated pulse contour method, the MostCare, in determining cardiac output (CO) in septic patients. METHODS: Thirty patients with septic shock admitted to an intensive care unit, receiving a norepinephrine infusion and requiring haemodynamic monitoring with a pulmonary artery catheter, were prospectively enrolled. Thermodilution measurements of CO (ThD-CO) were considered as the 'gold standard'. MostCare was connected to the monitoring system of the radial arterial pressure waveform to obtain a continuous CO calculation (MostCare-CO). ThD-CO and MostCare-CO measurements were recorded at three different haemodynamic states: baseline (T1), after raising mean arterial pressure (MAP) to 90 mm Hg by increasing the norepinephrine infusion (T2), and after returning the MAP to baseline value by decreasing vasopressor therapy (T3). A Bland-Altman and linear regression analyses were performed. RESULTS: A total of 90 paired ThD-CO and MostCare-CO measures were obtained (range 4.1-13.9 litre min(-1) for ThD-CO and 4.5-13.5 litre min(-1) for MostCare-CO). A good correlation between ThD-CO and MostCare-CO was observed (R = 0.93). The mean bias between the two techniques was -0.26 litre min(-1) (sd 0.98 litre min(-1)) and the 95% limits of agreement were -2.22 to 1.70 litre min(-1). The percentage of error was 25%. Pearson's R was 0.94, 0.92, and 0.93 at T1, T2, and T3, respectively. CONCLUSIONS: MostCare-CO and ThD-CO showed a good agreement at each time of the study. The reliability of the MostCare system was not affected by the vascular tone changes produced by a norepinephrine infusion.

Citrate anticoagulation during CVVH in high risk bleeding patients.

BACKGROUND: Regional citrate anticoagulation (RCA) is an effective form of anticoagulation for continuous renal replacement therapy (CRRT) in patients with contraindications to heparin. Its use has been very limited, possibly because of the need for special infusion solutions and difficult monitoring of the metabolic effects. OBJECTIVE: To investigate the safety and the feasibility of an RCA method for continuous veno-venous hemofiltration (CVVH) using commercially available replacement fluid. METHODS: We evaluated 11 patients at high risk of bleeding, requiring CVVH. RCA was performed using commercially available replacement fluid solutions to maintain adequate acid-base balance. We adjusted the rate of citrate infusion to achieve a post-filter ionized calcium concentration [iCa] <0.4 mmol/L when blood flow was <250 ml/min, or <0.6 mmol/L when blood flow was >250 ml/min. When needed, we infused calcium gluconate to maintain systemic plasma [iCa] within the normal range. RESULTS: Twenty-nine filters ran for a total of 965.5 h. Average filter life was 33.6+/-20.5 h. Asymptomatic hypocalcemia was detected in 6.9% of all samples. No [iCa] values <0.9 mmol/L were observed. Hypercalcemia (1.39+/-0.05 mmol/L) occurred in 2.5% of all samples. We observed hypernatremia (threshold 153 mmol/L) and alkalosis (threshold 7.51) in only 9.3% and 9.4% respectively of all samples, mostly concomitantly. No patient showed any signs of citrate toxicity. CONCLUSIONS: We developed a protocol for RCA during CVVH using commercially available replacement fluid that proved safe, flexible and applicable in an Intensive Care Unit (ICU) setting.