Journal of cardiothoracic anesthesia
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J Cardiothorac Anesth · Feb 1990
Systolic pressure measurement in the ascending aorta: augmentation at the aortic cannula sideport.
To assess whether arterial blood pressure measured at the sideport of the aortic cannula mirrors that measured within the ascending aorta, the two pressures were compared in 10 consecutive patients undergoing cardiopulmonary bypass. The mean arterial pressures (MAP) were equal both before and after bypass, but the sideport systolic arterial pressure (SAP) was 6.0 +/- 0.8 mm Hg higher than the aortic SAP before bypass and 9.1 +/- 0.5 mm Hg higher than the aortic SAP after bypass (P less than 0.001). Hematocrit, blood temperature, cardiac output, and heart rate did not correlate with the differences in SAP, suggesting that the higher SAP seen at the sideport was generated within the tube connecting the oxygenator to the aorta. ⋯ The SAP in the sideport decreased by 4 to 12 mm Hg in 12 of the 20 patients, while the MAP was unaffected by this maneuver. It is concluded that the MAP measured at the sideport of the aortic cannula closely reflects the MAP in the ascending aorta, whereas the SAP measured at the sideport does not reflect the aortic SAP. Thus, when aortic pressure is measured at the sideport to confirm an artificially low radial arterial pressure, systolic amplification at the sideport might simulate or exaggerate radial artery hypotension.
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J Cardiothorac Anesth · Feb 1990
Letter Case ReportsInadvertent thermal injury from surgical instruments.
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J Cardiothorac Anesth · Dec 1989
Activated partial thromboplastin time-protamine dose relation in the presence and absence of heparin.
A protamine titration is one of the methods to determine the protamine dose necessary to neutralize heparin. The protamine dose response was studied with the activated partial thromboplastin time (APTT) in the presence of a known amount of heparin and in the absence of heparin, using freshly prepared human plasma. When heparin was present in the plasma, APTT values plateaued between a minimal neutralizing dose of protamine and a protamine dose five times greater. ⋯ The increases in APTT values caused by an increase of 50 micrograms/mL of protamine were significantly greater without heparin than they were in the presence of heparin. These results suggest that protamine has a wide safety range when neutralizing heparin without exerting its own anticoagulant action. Although the mechanisms are under speculation, the heparin-protamine complex may inhibit the anticoagulant action of protamine in vitro.
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Many patients undergo cardiac surgery with preexisting congenital and acquired coagulation defects. Almost all of these can be recognized and corrected preoperatively. CPB itself induces a variety of abnormalities of coagulation, affecting plasma proteins, platelets, and the fibrinolytic system. ⋯ Exciting advances have been made in the use of synthetic alternatives to blood products. Both DDAVP and aprotinin seem promising in this respect, but more investigation is needed into the mechanisms of action and possible thrombotic complications of these drugs. In the future, anesthesiologists and surgeons may look forward to more safe and effective therapy of bleeding in cardiac surgical patients.