Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.
  Table of Contents / Chapter 39:
Anesthesia for Microsurgery
 
 

Good communication with the referring medical facility is essential. When single or multiple limbs have been partially or completely amputated, major hemorrhage often occurs before the patient reaches medical care. It is essential that adequate resuscitation take place in the referring hospital, including adequate crystalloid and blood replacement before the injured patient is moved to the replantation center. The patient must also be evaluated for other injuries that may be life-threatening during the transfer. If the patient is hemodynamically unstable on arrival at the replantation center, further resuscitation is necessary. The blood bank needs to be immediately alerted so that adequate amounts of blood can be typed and crossmatched. Major blood loss is rarely, if ever, a problem in hand or finger injuries, and a hyperdynamic circulatory state is often seen because of pain and anxiety. Small amounts of intravenous narcotics in the emergency room often help relieve the pain, and similarly, small amounts of diazepam or midazolam help calm the extremely anxious patient.

Emergency replant surgery often involves patients who have recently eaten and drunk. The trauma patient must be considered to have a full stomach and be at risk for aspiration of gastric contents if general anesthesia or heavy sedation is planned. The importance of this issue cannot be overemphasized. The "time since the last meal" cannot be used to ascertain a full stomach in the trauma patient. Catechole secretion due to the injury can greatly affect normal gastrointestinal function. Therefore, we recommend all emergency replantation patients be treated as having a "full stomach." Standard procedures should be rapid sequence induction with cricoid pressure, followed by rapid endotracheal intubation, cuff inflation, and awake extubation. Use of preoperative cimetidine to raise gastric pH, and metaclopramide to increase gastric emptying have both been suggested. In the acute trauma patient, however, 30 cc of sodium citrate is probably most effective in acutely raising the pH of the gastric contents. Nevertheless, if aspiration does occur, particulate matter in the lungs will cause severe problems, even if the pH has been raised. With routine use of the rapid sequence induction with cricoid pressure and awake extubation, we have never had an occurrence of aspiration.

 

A brief, well-planned discussion with the patient can quickly cover past medical history, medications, drug allergies, and previous anesthetic experiences. An explanation of the planned anesthetic techniques and the reassurance that he or she will not feel any pain during surgery will usually help a great deal to calm the anxious patient.

Depending upon the medical history, physical findings, and age of the patient, basic laboratory studies, electrocardiogram, and chest x ray are done as indicated. Our only routine laboratory study for everyone is a hematocrit. Many studies have shown that, even during the course of a prolonged anesthetic, serum electrolytes and arterial blood gas values, remain relatively constant if ventilation is carried out appropriately. If, however, significant amounts of ischemic tissue are surgically reperfused, the systemic pH must be continuously evaluated.

General Anesthesia for Microvascular Surgery

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