Measurement of cardiac output: a comparison between transpulmonary thermodilution and uncalibrated pulse contour analysis.

BACKGROUND: Recently, continuous monitoring of cardiac output (CO) based on pulse contour analysis (Vigileo) has been introduced into practice. In this clinical study, we evaluated the accuracy of this system by comparing it with the transpulmonary thermodilution technique (TPID) in septic patients. METHODS: We studied 24 mechanically ventilated patients with septic shock (16 male, 8 female, age 26-77 yr) receiving treatment with norepinephrine who for clinical indication underwent haemodynamic monitoring by the transpulmonary thermodilution technique using a PiCCO plus system (Pulsion Medical Systems, Munich, Germany). In parallel, arterial pulse contour was applied using the femoral arterial pressure curve (FloTrac pressure sensor, Vigileo monitor, Edwards Lifesciences, Irvine, USA). After baseline measurement, mean arterial pressure was elevated by increasing norepinephrine dosage, and CO was measured again before mean arterial pressure was reduced back to baseline levels. Fluid status and ventilator settings remained unchanged throughout. At each time point, CO by transpulmonary thermodilution was calculated from three central venous bolus injections of 15 ml of saline (<8 degrees C). Linear regression and the Bland-Altman method were used for statistical analysis. RESULTS: Overall, CO was 6.7 (sd 1.8) (3.2-10.1) litre min(-1) for CO(TPID) and 6.2 (2.4) (3.0-17.6) litre min(-1) for CO(Vigileo((R))). Linear regression revealed: CO(Vigileo) = 1.54 + 0.72 x CO(TPID) litre min(-1), r(2) = 0.26 (P < 0.0001). Mean bias between techniques [CO(TPID)-CO(Vigileo)] was 0.5 litre min(-1) (SD 2.3 litre min(-1)). Correlation coefficients at the three time points were not significantly different from each other. CONCLUSIONS: Pulse contour analysis-derived CO (Vigileo system) underestimates CO(TPID) and is not as reliable as transpulmonary thermodilution in septic patients.

Positive end-expiratory pressure does not affect indocyanine green plasma disappearance rate or gastric mucosal perfusion after cardiac surgery.

BACKGROUND AND OBJECTIVE: Positive end-expiratory pressure (PEEP) may affect hepato-splanchnic blood flow. We studied whether a PEEP of 10 mbar may negatively influence flow-dependent liver function (indocyanine green plasma disappearance rate, ICG-PDR) and splanchnic microcirculation as estimated by gastric mucosal PCO2 (PRCO2). METHODS: In a randomized, controlled clinical study, we enrolled 28 patients after elective cardiac surgery using cardiopulmonary bypass. In 14 patients (13 male, 1 female; age 48-74, mean 63 +/- 7 yr) we assessed ICG-PDR and PRCO2 on intensive care unit admission with PEEP 5 mbar, after 2 h with PEEP of 10 mbar and again after 2 h at PEEP 5 mbar. Inspiratory peak pressure was adjusted to maintain normocapnia. Fourteen other patients (8 male, 6 female; age 46-86, mean 68 +/- 11 yr) in whom PEEP was 5 mbar throughout served as controls. All patients underwent haemodynamic monitoring by measurement of central venous pressure, left atrial pressure and cardiac index using pulmonary artery thermodilution. RESULTS: While doses of vasoactive drugs and cardiac filling pressures did not change significantly, cardiac index slightly increased in both groups. ICG-PDR remained unchanged either within or between both groups (PEEP10 group: 24.0 +/- 6.9, 22.0 +/- 7.9 and 25.5 +/- 7.7% min-1 vs. controls: 22.0 +/- 7.5, 23.8 +/- 8.4 and 21.4 +/- 6.5% min-1) (P = 0.05). The difference between PRCO2 and end-tidal PCO2 (PCO2-gap) did not change significantly (PEEP10 group: 1.1 +/- 0.9, 1.3 +/- 0.7 and 1.3 +/- 0.9 kPa vs. controls: 0.8 +/- 0.5, 0.9 +/- 0.5 and 0.9 +/- 0.5 kPa). CONCLUSION: A PEEP of 10 mbar for 2 h does not compromise liver function and gastric mucosal perfusion in patients after cardiac surgery with maintained cardiac output.

[Procalcitonin as an early marker of sepsis]. / Prokalzitonin-Schnelltest als Frühmarker einer Sepsis.

A 64-year-old male with an APC resistance (factor V mutation Leiden) and interrupted oral anticoagulation due to an erosive gastritis, was admitted to hospital for increasing dyspnoea. Transthoracic echocardiography revealed a floating thrombus via an open foramen ovale in both atria reaching both ventricles. Sonography showed multiple stage thrombosis of the left leg reaching to the V. femoralis superficialis. A few months previously, peripheral pulmonary artery embolization has been confirmed by scintigraphy. The patient was transferred to our hospital and underwent emergency surgery for closure of the atrial septum defect and thrombus removal. On the 4th postoperative day, the patient was transferred to the normal ward, however, on the 10th postoperative day, the patient developed a symptomatic transitory psychotic syndrome and became hypotensive before he was transferred to the ICU. Due to impaired oxygenation and the patient's history, a new pulmonary artery embolization was suspected. After ICU admission, the patient required increasing norepinephrine support and rapidly developed septic fever. However, serum procalcitonin was elevated and a computed tomography (skull, chest and abdomen) was performed for a focus search. Pulmonary artery embolism could be ruled out but an oval structure near to the ampulla recti (ca. 30 x 20 mm) was identified as an abscess and immediate abscess incision was performed. After surgery, the further course was characterized by a steep fall in vasopressor support and body temperature. The patient was transferred to the normal ward on the 2nd postoperative day. This case shows that procalcitonin allows early and reliable diagnosis of sepsis in patients with undefined shock.

Increasing cardiac output by fluid loading: effects on indocyanine green plasma disappearance rate and splanchnic microcirculation.

BACKGROUND: Sufficient cardiac pre-load for maintaining adequate cardiac output is a major goal in the treatment of critically ill patients. We studied the effects of increasing cardiac output by fluid loading on the indocyanine green plasma disappearance rate (ICG-PDR) and gastric mucosal regional CO2 tension (PRco2) as an indicator of splanchnic microcirculation. METHODS: With approval by our ethics committee and written consent, we studied post-operatively 12 patients (1 female, 11 males; 66 +/- 13 years) with elective coronary artery bypass grafting (n = 10) or aortic valve replacement (n = 2). All patients had received pulmonary artery and left atrial catheterization previously for clinical indications. Cardiac output and filling pressures were measured immediately after intensive care unit (ICU) admission and 1 h after the beginning of fluid loading. RESULTS: Overall, 630 +/- 130 ml of 6% hydroxyethylstarch (130 kDa) was infused with the splanchnic perfusion pressure remaining constant. Norepinephrine and epinephrine dosages were unchanged. The cardiac index increased significantly from 2.8 +/- 0.7 to 3.5 +/- 0.6 l/min/m2 and the stroke volume index from 30 +/- 7 to 38 +/- 8 ml/m2. ICG-PDR showed no significant change, i.e. from 21.2 +/- 6.5 to 21.6 +/- 6.5%/min. Gastric mucosal PRco2 and the Pco2 gap (difference between regional and end-tidal CO2 tension) were constant, i.e. changed from 5.1 +/- 0.8 to 5.5 +/- 1.1 kPa and from 0.9 +/- 0.5 to 1.0 +/- 0.7 kPa, respectively. CONCLUSION: Increasing cardiac output to supranormal values by fluid loading is not associated with a significant change in ICG-PDR or gastric mucosal PRco2.