Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.
  Table of Contents / Chapter 39:
Anesthesia for Microsurgery
  Microvascular surgery is a rapidly growing specialty. Despite advances, the optimal anesthetic management has yet to be defined. Controlled clinical studies are few, with small numbers of patients in each. There are proponents for a wide variety of techniques and pharmacologic agents. There are advocates of general anesthesia, continuous regional anesthesia, general anesthesia combined with continuous regional anesthesia, all of the above combined with anticoagulants and antiplatelet drugs, a wide variety of long and short-acting vasodilators, agents affecting blood viscosity, and even normovolemic hemodilution. In terms of proposed appropriate intraoperative monitoring, there are proponents of most known invasive and noninvasive techniques.

Since 1972, when the clinical practice of microvascular surgery was begun at the Davies Medical Center, we have used a wide variety of anesthetic techniques and agents. In addition to the approximately 1,500 replantation and reconstructive procedures, many neurovascular procedures have also been performed here. From 1972 to 1986, approximately 550 extracranial to intracranial microvascular arterial bypasses were performed. Many within this group of neurosurgical patients were elderly, with generalized arteriosclerosis and hypertension, and had the multiple organ problems associated with these diseases. In contrast, most of the patients who had replantation, free flap transfer, or other major reconstructive procedures were young and healthy. The lessons we learned from this large group of microsurgical patients helped us to develop a general approach to all microsurgical anesthesia. Because there were few, if any, reports of the anesthetic management for these operations initially, we felt that a straight-forward anesthetic technique would be best, using the time-tested principles of general anesthesia: avoiding hypotension, hypoxia, hypocapnia, and hypothermia. This technique has certainly proven correct. Advances in instrumentation have

  made monitoring these cases so simple that they are now routine. Introduction of isoflurane has provided us with a general anesthetic agent that is a potent vasodilator during the operative procedure, as well as one that has little or no toxicity, an important factor in the prolonged anesthetic.

The following equipment is used to monitor routine and special cases.


   BP-cuff or dynamop
   Esophageal stethoscope
   Pulse oximeter
   End-tidac C02
   Core temperature
   Urinary catheter
Special Circumstances
   Intra-arterial cannula
   Central venous cannula
   Pulmonary artery catheter

Preanesthetic Considerations

When a patient enters the hospital for elective surgery, there is time for evaluation of any medical problems. Necessary tests can be performed, and the anesthetic care planned accordingly. The situation is quite different for the trauma patient, who is often brought from a considerable distance for replantation of amputated limbs or digits.

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