Our aim was to compare a continuous infusion of remifentanil with intermittent boluses of fentanyl as regards the perioperative hormonal stress response and inflammatory activation in coronary artery bypass graft patients under sevoflurane-based anaesthesia.

In all, 42 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to a fentanyl group (n = 21, total fentanyl dose 2.6 ± 0.3 mg), or a remifentanil group (n = 21, infusion rate 0.25 μg kg−1 min−1). Haemodynamics, plasma levels of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone, cortisol, complement activation (C3a, C5b-9), interleukin (IL)-6, IL-8 and tumour necrosis factor-α were measured at T1: baseline, T2: intubation, T3: sternotomy, T4: 30 min on cardiopulmonary bypass, T5: end of surgery and T6: 8 h postoperatively. Troponin T and creatine kinase-MB were measured postoperatively.

Patients in the remifentanil group were extubated significantly earlier than fentanyl patients (240 ± 182 min vs. 418 ± 212 min, P = 0.006). Stress hormones 30 min after start of cardiopulmonary bypass showed higher values in the fentanyl group compared to the remifentanil group (antidiuretic hormone (ADH): 39.94 ± 30.98 vs. 11.7 ± 22.8 pg mL−1, P = 0.002; adrenocorticotropic hormone: 111.5 ± 116.8 vs. 21.81 ± 24.71 pg mL−1, P = 0.01; cortisol 185 ± 86 vs. 131 ± 82 ng mL−1, P = 0.04). The interleukins were significantly higher at some perioperative time points in the fentanyl group compared to the remifentanil group (tumour necrosis factor: T5: 3.57 vs. 2.37; IL-6: T5: 4.62 vs. 3.73; and IL-8: T5: 4.43 vs. 2.65 and T6: 2.61 vs. 1.13). However, cardiopulmonary bypass times and aortic cross-clamp times were longer in the fentanyl group, which may to some extent account for the differences.

The perioperative endocrine stress response was attenuated in patients supplemented with continuous remifentanil infusion as compared to intermittent fentanyl.

Arterial pulse waveform analysis has been proposed for cardiac output (CO) determination and monitoring without calibration or thermodilution (FloTrac™/Vigileo™; Edwards Lifesciences, Irvine, CA, USA). The accuracy and clinical applicability of this technology has not been fully evaluated. We designed this prospective study to compare the accuracy of the FloTrac™ system (COFT) vs. pulmonary artery catheter standard bolus thermodilution (COPAC) in patients undergoing coronary artery bypass grafting.

We studied 11 patients referred for coronary artery bypass grafting. COFT and COPAC were determined at six time points in the operating room including before and 5 min after volume expansion (500 mL 6% hetastarch). Measurements were performed on arrival in the intensive care unit and every 4 h afterwards. Bland–Altman analysis was used to assess the agreement between COFT and COPAC.

COPAC ranged from 2.0 to 7.6 L min−1 and COFT ranged from 1.9 to 8.2 L min−1. There was a significant relationship between COPAC and COFT (r = 0.662; P < 0.001). Agreement between COPAC and COFT was −0.26 ± 0.87 L min−1. Volume expansion induced a significant increase in both COPAC and COFT (from 3.4 ± 0.8 to 4.4 ± 1.0 L min−1; P < 0.001 and from 3.9 ± 1.2 to 5.0 ± 1.1 L min−1; P < 0.001, respectively) and there was a significant relationship between percent change in COPAC and COFT following volume expansion (r = 0.722; P = 0.01).

We found clinically acceptable agreement between COFT and COPAC in this setting. This new device has potential clinical applications.

Respiratory variations in pulse oximetry plethysmographic waveform amplitude (ΔPOP) are related to respiratory variations in arterial pulse pressure (ΔPP) in the critical care setting. The aims of this study were to test the hypothesis that in mechanically ventilated patients undergoing general anaesthesia, ΔPOP calculation is feasible and can detect changes in preload.

Twenty-five mechanically ventilated patients were studied immediately after induction of general anaesthesia. Haemodynamic data (mean arterial pressure [MAP], central venous pressure [CVP], ΔPP and ΔPOP) were recorded at baseline, before and after tilting the patient from anti-Trendelenburg to Trendelenburg position in order to induce preload changes.

Change from anti-Trendelenburg to Trendelenburg position induced changes in MAP (58 ± 9 to 67 ± 10 mmHg, P < 0.05), CVP (4 ± 4 to 13 ± 5 mmHg, P < 0.05), ΔPP (14 ± 8 to 7 ± 5%, P < 0.05) and ΔPOP (17 ± 12 to 9 ± 5%, P < 0.05). There was a significant relationship between ΔPOP in anti-Trendelenburg position and percent change in MAP after volume expansion (r = 0.82; P < 0.05).

ΔPOP can be determined in the operating room and is influenced by changes in preload. This new index has potential clinical applications for the prediction of fluid responsiveness.