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Anesthetic Management:
- Utilize measures for reducing heat loss due to loss of insulating properties of the skin, evaporative loss of water from the eschar, and depression of metabolic rate by general anesthesia. (warm room to 25o C, fluid warmers, HME, and bair hugger)
- Along with other standard monitoring equipment, an arterial line and CVP/PA cath is beneficial. Measurement of arterial blood gases and pH are crucial in the management of inhalation injury, therefore, arterial monitoring is imperative. Blood pressure monitoring through a BP cuff may be difficult with large surfaces of injury. An arterial line enables accurate measurement of BP without occupying too large an area.
- Oxygenation is crucial in burn patients particularly those patients suspected of carbon monoxide poisoning. For example, if a patient is breathing room air, the elimination half-time for carboxyhemoglobin is 250 minutes. Administration of 100% oxygen increases the dissociation of carbon monoxide from hemoglobin and decreases this time to about 50 minutes.
- The patient presents to OR with an ETT in place. Placement is assessed with auscultation. Mechanical factors due to burn injury may interfer with pulmonary function. Chest and abdominal burns can lead to restricted chest wall motion, as eschar contracts and hardens. Restrictions in chest excursions are further complicated by abdominal distention associated with ileus. (insert NG to decompress stomach)
- Provide adequate sedation and analgesics for intubated patient with burns presenting for surgery. Second degree burns are often painful, and analgesics alleviate the discomfort and pain associated with transport and positioning. Versed may be given for amnesia. Benzodiazepines doses may need to be decreased or titrated to effect, due to the decreased concentration of albumin after burn injuries.
- Sodium pentothal, an induction agent, is used to fascilitate unconsciouness. One-half induction dose of SPT is sufficient due to the lack of stimuli elicited during direct laryngoscopy.
- Muscle relaxants are utilized to ensure immobility and aid surgeons in their repair as well as allow the anesthetist to utilize lower concentrations of inhalation agents. Requirements for non-depolarizing muscle relaxants are increased due to the increases in extra-junctional sites associated with burn injuries and increased plasma concentration of alpha-1 acid glycoprotein. Therefore, muscle relaxation is best monitored with a neuromuscular blockade monitor.
- Volatile inhalation agents such as Forane are used to further enhance analgesia, amnesia, and sustain surgical anesthesia.
- Fluid management is patterned according to the Parkland formula for fluid resuscitation following burn injury. (4 ml/kg) ( % of TBSA), 2/3 of which is given in the first 8 hours. The formula provides a guideline, but fluid management may also be managed through careful monitoring of urine output and CVP values (maintaining u/o at 1 cc/kg/hr).
Fluid Management
Parkland Formula
- 4 cc/kg of balanced salt solution x %TBSA burned
- 2/3 given in the first 8 hours and 1/3 in the subsequent 16 hours