Factoid: The Airway and Burns

The assessment of the airway is the first priority in evaluation of the burn patient.

  • Upper airway obstruction
  • Inability to handle secretions
  • Hypoxemia despite 100% O2
  • Obtundation/decreased GCS
  • Muscle fatigue suggested by high or low respiratory rate
  • Hypoventilation (PCO2 >50 or pH<7.2
Table 60-3 Rosen’s Emergency Medicine

 

Your Next Patient #1: A 45 year old man with burns

The following case is meant to simulate an oral examination question. Information will be presented, and the candidate asked to discuss the situation or answer specific questions. The information will be presented sequentially. This is not intended to be a comprehensive topic review, rather it is meant to examine specific candidate competencies.

You are the emergency physician in a medium sized community hospital. Your next patient is a 45 year old man who was in a house fire. He was alone in his bungalow when it caught fire, neighbours found him inside the house, unconscious and partially under some debris and dragged him to safety. The fire department arrived and found the house ‘fully engulfed’. They put oxygen on the patient and brought him to hospital, where is he placed in your resuscitation bay.

The patient has loud respirations and is moaning and rolling about the stretcher. There are obvious facial burns as well as burns on the forearms and hands. The clothes appear to be charred, particularly over the chest. Vital signs are: HR 125 BP 135/75 RR 35 O299% on 10lpm by face mask.

  • The candidate should use an ABCDE approach for the initial part of the assessment
  • The candidate should comment on potential for difficult airway and the importance of securing an early definitive airway
  • The candidate should comment on possibility of thermal injury to the airway
  • The candidate should establish intravenous access and recognize the tachycardia
  • The patient should be fully exposed and the charred clothes removed
  • The patients pain should be addressed
  • A secondary survey should be done in search of other injuries

The airway is secured with an endotracheal tube and there is good bilateral air entry and normal end tidal capnography. Peripheral pulses are present in all 4 limbs. The secondary survey reveals partial and full thickness burns over the face and chest, circumferential burns around the left arm and to the palms of both hands. There is a large area of bruising over the left flank. The vital signs are unchanged.

  • The candidate should be able to calculate the burned body surface area of 24.5%
  • The candidate should calculate an initial fluid regime using the Parkland formula or similar (4ml per %BSA x kg with 50% given over the first 8 hours post injury and the remainder over the next 16 hours)
  • The candidate should be aware that there is potential for other injuries in this patient as evidenced by the flank bruising and respond to this cue
  • The candidate should recognize the potential for circulatory compromise of the left arm and potential need for escharotomy
  • A foley catheter should be placed
  • The candidate should state that this patient requires transfer to a specialized burn centre
  • Appropriate ancillary tests should be obtained (blood gas, co-oximitry, cbc, electrolytes, renal function, lactate, chest and pelvis x-rays, ECG, FAST exam of the abdomen)

  • Partial and full thickness burns >20% BSA, or >10% if age <10 or >50
  • Full thickness burns >5% BSA
  • Burns to special areas: face, eyes, ears, hands, feet, genitalia and perineum, overlying joints
  • Chemical burns
  • Inhalation injury
  • Burns in patients with significant preexisting illness
  • Burns associated with other trauma

A saturation of 99% seems unusually high in a patient with significant inhalation injury. In this case it is worrisome for carbon monoxide toxicity. The patient should be treated with high FiO2 until cooximetery for CO is available.

The patients vital signs remain unchanged. Ancillary tests show the following post intubation blood gas: pH 7.35 PaO2 105 PCO2 35 HC03 22 Base excess -2. CBC, electrolytes and renal function are normal, lactate is 2. X-rays and ECG are normal. FAST is negative.

He is accepted for helicopter transfer to a nearby burn centre.The accepting doctor asks if your local surgeon can do an escharotomy of the arm before transfer and you arrange this. The accepting physician also asks you if you think the patient should be treated for potential cyanide toxicity.

The candidate should discuss the risk factors for cyanide toxicity in fires, especially with reference to household plastics, industrial fires and closed spaces. The candidate should recognize the mechanism of toxicity of cyanide, inactivation of cytochrome A3 oxidase, which uncouples mitochrondrial oxidative phosphorylation shifting cells to anaerobic metabolism. The candidate should recognize that cyanide toxicity results in a significant lactic acidosis. Since our patient has neither acidosis nor elevated lactate significant cyanide toxicity is excluded.

This case examines a candidates competency in managing the initial phase of a straightforward major burn case. The candidate is expected to manage the case in an organized way, such as the ABCDE system from ATLS. It is expected that the candidate will manage the airway and discuss the possible complications. The possibility for other injuries much be recognized and the candidate must make arrangements to move the patient to definitive care. Follow-up questions define the candidates knowledge of criteria that necessitate transfer for burn patients as well as knowledge of potential for carbon monoxide and cyanide toxicity.

This is designed to be a very straightforward oral exam question.