Surgery of the Pelvic and Sacral Tumor by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9789402419450
Publisher: Springer Netherlands

18.2 Intraoperative Monitoring

The operation time for pelvic or sacral tumors always lasts long, and patients should be placed in a comfortable surgical position to avoid neural impairment. Body regions like the head, neck, and joints should be protected, and a cushion should be placed under the axilla when patients are placed in a lateral position.

Before surgery, multiple venous access should be established to facilitate intraoperative blood transfusion and fluid infusion. Central venous and radial artery catheter should be applied to monitor intraoperative circulatory system well-timed. Both surgeons and anesthetist should pay close attention to the volume of intraoperative blood loss and perform blood transfusion without delay because the real volume of intraoperative blood loss is often underestimated. Timely blood transfusion is beneficial in avoiding coagulation dysfunction and circulatory failure.

Intraoperative controlled hypotension is reported to decrease the volume of blood loss by 50% and be more effective than intraoperative hemodilution. Nitrates such as sodium nitroprusside and nitroglycerin are the most commonly used antihypertensive drugs. Another method to control intraoperative blood loss is hemodilution including preoperative hemodilution (isovolemic hemodilution) and hypervolemic hemodilution. Isovolemic hemodilution means letting blood from arteries or veins and transfusing equivoluminal colloid solution and/or crystalloid solution at the same time after the anesthetic with the purpose of reducing hematocrit (Hct) rather than blood volume. The blood drew out is transfused back after the massive hemorrhage is controlled. Hypervolemic hemodilution means alleviating the central venous pressure (CVP) to the high limit of normal value (10–12 cm H2O) by transfusing crystalloid solution and colloid solution (1:1) after the anesthetic to expand the volume of endovascular and extracellular fluid. The expansion of endovascular and extracellular fluid leads to hemodilution (Hct ≥ 30%) which decreases the loss of blood cell components and strengthens the ability of defending against hemorrhagic shock when massive hemorrhage is encountered.

Intraoperative monitoring of the abdominal aortic balloon catheter: commonly we use arterial piezometer for dynamic monitoring of the whole course. An ambulatory blood pressure monitoring device is connected to the catheter after successful puncturing. We can indirectly keep track of the situation and parameters of lower limb arteries by comparing the parameters to that of radial arteries. The arterial waveform breaking to a straight line and arterial number reducing to a low fixed numerical value mean the blood supply for the main arteries of lower limbs is excluded and the operation can be performed under the occlusion. Surgeons can master the effect of occlusion by intermittent observation of the numerical value. Intermittent trace of heparin saline pumped through the catheter can effectively avoid the formation of femoral thrombosis.

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