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.

[Click here to toggle visibility of the answers]

College answer

Not available.


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.


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.