DOI: 10.1097/00000539-199802001-00243
,
Issn Print: 0003-2999
Publication Date: 1998/02/01
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Excerpt
Previous studies have identified falsely low radial artery pressures after CPB [1]. The resulting difficulties may be overcome by the use of a new aortic cannula which allows the measurement of aortic pressure during and after CPB. This cannula was used to evaluate the influence of different cannulation sites on blood pressure errors measured by radial and femoral artery catheters.
Methods: Written informed consent and approval by the Ethic Committee were obtained for this controlled prospective, randomized study. All patients underwent coronary artery bypass grafting with normothermic CPB. The anesthetic regimen was standardized and consisted of sufentanil and propofol in mean doses of 5 +/- 2 (SD) [micro sign]g/kg and 10 +/- 3 (SD) mg/kg, respectively.
Thirty patients with a successful first puncture of the arterial vessel were allocated to the groups 1) a. radialis left (rad I), 2) a. radialis right (rad r), and 3) a. femoralis left (fem). Measuring devices in all cases included an 18G teflon catheter and the 24F Jostra aortic cannula. After calibration, a Hewlett Packard monitor recorded aortic and peripheral pressures at 1-minute intervals.
Points of measurement were defined: 5[prime] after start of CPB, 5[prime] after aortic clamp, 5[prime] after start of pulsatile flow, 5[prime] after opening of aortic clamp, 5[prime] before end of CPB and 5[prime] after end of CPB. Only plausible values were taken into account (Delta Pmean < 35 mmHg, mean aortic pressure > 20 mmHg). Differences of mean pressures greater than 10 mmHg were considered clinically important. In addition, all recorded 5936 values were compared among groups. Analysis of variance was performed and subsequent tests (t-test) where appropriate.
Results: The patients of all groups were comparable in size, weight, gender, age, vascular diseases, drug treatment, durations of anesthesia, surgery and CPB. There was a significant increase of mean pressure differences in all groups during CPB (Table 1). Pressure differences increased more in both radialis than in the fem group. Five out of 10 patients in each radialis group showed mean pressure differences > 10 mmHg in more than 5% of all available values. Especially at the end of CPB, 4 patients in rad 1 and 1 patient in rad r group showed clinically relevant differences. In contrast, there was no patient in the fem group with clinically relevant differences of mean pressure.
Conclusion: The new 24F aorta cannula (Jostra) is an easy to use instrument to identify falsely low radial and femoral pressures. Furthermore, the additional pressure line may be helpful to detect a wrong position of the aortic cannula.
