Question 20

College answer

Not available.

Discussion

The differences in management of this patient compared to a non-obese patient:

A different pattern of injury is to be expected:

• Injury scores are lower in obese patients (Arbabi et al, 2003)
• Pattern of blunt trauma is different (Boulanger et al, 1992)
  • Injuries that are more likely:
    • pulmonary contusion
    • rib fractures
    • pelvic injuries
    • knee dislocations (Fuchs et al, 2014)
    • extremity fractures
    • proximal upper extremities seem to get it worst (Evans et al, 2011)
  • Injuries that are less likely:
    • head injuries
    • liver injuries
• "Obese people injured in vehicular crashes had a similar injury pattern with no difference in seating position, direction of impact, seat belt use, and ejection."

Differences in managing the airway of a morbidly obese trauma patient:

• Difficult airway; difficult bag-mask ventilation more likely than actual difficult intubation.
• Short handle may be required for direct laryngoscopy; most people would just resort to the videolaryngoscope.
• When intubating, the FRC is small and the patient will become hypoxic rapidly, which means fewer attempts will be possible.
• Increased risk of obstruction, even when awake
• When obtunded, a virtual certainty of obstruction

Differences in managing the ventilation of a morbidly obese trauma patient:

• Poor chest wall compliance
• Increased risk of atelectasis
• Obesity hypoventilation syndrome
• Difficult access for chest drains
• Difficult windows for trauma TTE
• Difficult auscultation and percussion, eg. for pneumothorax
• Increased aspiration risk

Difference in managing haemodynamics in a  morbidly obese trauma patient:

• Difficulty measuring accurate blood pressure (need for appropriate size cuff)
• Realistic possibility that no cuff will be appropriate and arterial access may be required
• Difficult IV access- CVC as well as PIVC; the college answer recommends to go straight for the intraosseous needle
• Intraosseous access is hardly fool-proof and can also be frustrated by obesity, considering especially the likelihood of there being bilateral knee prostheses
• Possibility of pulmonary hypertension, cor pulmonale or CCF makes haemodynamic management more complex

Difference in managing sedation, analgesia and C-spine protection in the morbidly obese trauma patient

• Likely, CO₂ retention and narcosis (influences doses of induction drugs)
• Medullary sensitivity to CO₂ will be even more reduced by opiates
• Some sort of syndromic condition may complicate neurological assessment (eg. Prader Willi syndrome)
• Log rolling will require additional assistants, or some sort of unusual equipment.

Differences in the investigations 

• Morbid obesity is one of the limitations of FAST
• Difficult insonation of the appropriate spaces; image quality is likely to be poor
• Pericardial fat can be misinterpreted as clotted blood
• Perinephric fat may be misinterpreted as intraperitoneal free fluid
• The advantage is, if you can't fit into the CT scanner this is all you've got.