Question 20

A morbidly obese 49-year-old female is referred from the Emergency Department to ICU following a motor vehicle crash and has left sided fractured ribs and a flail chest. She has seatbelt bruising over her chest wall and abdomen. She has had a CT scan of head, neck, chest, abdomen and pelvis that has shown left rib fractures and left sided lung infiltrates. There are no other injuries evident. She is receiving oxygen via a Hudson mask, is conscious and has significant left sided pleuritic chest pain.

Discuss the differences in management of this patient compared to a non-obese patient.

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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.

References

Bochicchio, Grant V., et al. "Impact of obesity in the critically ill trauma patient: a prospective study." Journal of the American College of Surgeons 203.4 (2006): 533-538.

Diaz Jr, Jose J., et al. "Morbid obesity is not a risk factor for mortality in critically ill trauma patients." Journal of Trauma and Acute Care Surgery 66.1 (2009): 226-231.

Lambert, David M., Simon Marceau, and R. Armour Forse. "Intra-abdominal pressure in the morbidly obese." Obesity surgery 15.9 (2005): 1225-1232.

Boulanger, Bernard R., et al. "Body habitus as a predictor of injury pattern after blunt trauma." Journal of Trauma and Acute Care Surgery 33.2 (1992): 228-232.

Dhungel, Vinayak, et al. "Obesity delays functional recovery in trauma patients." journal of surgical research 193.1 (2015): 415-420.

Ciesla, David J., et al. "Obesity increases risk of organ failure after severe trauma." Journal of the American College of Surgeons 203.4 (2006): 539-545.

Arbabi, Saman, et al. "The cushion effect." Journal of Trauma and Acute Care Surgery 54.6 (2003): 1090-1093.

Evans, David C., et al. "Obesity in trauma patients: correlations of body mass index with outcomes, injury patterns, and complications." The American surgeon 77.8 (2011): 1003-1008.

Fuchs, I., et al. "Vascular Injury in Obese Patients after Ultra-Low-Velocity Trauma." J Anesth Clin Res 5.488 (2014): 2.