Trauma in the Bariatric Population

The World Health Organization estimates that obesity has more than doubled worldwide since 1980. In 2014, the obese population was estimated at 600 million, with an additional 1.3 billion people classified as overweight; 39% of adults aged 18 years and over were classified as overweight in 2014, and 13% were classified as obese. This is a significant percentage of the general population, and has clinical and logistical implications for the trauma care of this patient population.1

Cardiovascular Considerations
A Swiss study suggests that obese trauma patients present in hypovolemic shock more often than overweight, normal weight or underweight trauma patients, and are inadequately fluid resuscitated. Nelson et al also found that of their trauma patients presenting with systolic blood pressures less than 90, 14.9% were obese, as opposed to 6.7% of the underweight patients. The researchers suggested that fluid resuscitation is calculated based on ideal body weight, and therefore the obese patient is significantly underresuscitated.

It can be more challenging to obtain accurate blood pressures in the obese population; appropriately sized blood pressure cuffs are critical to the rapid identification and treatment of hypotension in the obese trauma patient. Similarly, obtaining vascular access is often a challenge in the patient with a lot of subcutaneous tissue. If immediate vascular access cannot be obtained, alternate approaches such as intraosseous access and central venous catheterization should be considered.

Winfield et al also suggest that obese patients seem to take longer to resolve metabolic acidosis; this may be due to the inadequate fluid resuscitation described by Nelson et al. Obese patients present with lower hemoglobin levels which may contribute to underperfusion; also, possibly due to inadequate fluid resuscitation this problem is prolonged, leading to a 90% development of multisystem organ failure in obese patients whose metabolic acidosis was not adequately resolved.3

Respiratory Considerations
The assessment of respiratory status in the obese patient can be difficult, depending on the amount of subcutaneous thoracic tissue. Auscultation of breath sounds may be difficult, impeding rapid identification of pneumothorax. Research suggests that obese patients have smaller total lung volumes, restricting ventilation. Although pulmonary injuries are more prevalent in the obese population, the occurrence of pneumothorax and intra-abdominal injuries are lower. Increased thoracic body mass or waist circumference typically seen in obese persons may explain these patterns.

SEE ALSO: Earn CE: Treatment of Obesity

Diagnosing blunt traumatic injuries of the chest in the obese patient can be difficult because auscultation and percussion may give less accurate information due to the cushion effect from subcutaneous tissue. An alternative assessment option is palpation of the chest wall for crepitus from subcutaneous air. Physical findings can also be a red flag, indicating a need for alternate imaging to rule out pneumo/hemothorax. Specifically, the patient found to have subcutaneous emphysema, pulmonary contusion or rib fractures on exam should be further evaluated with CT chest to exclude any underlying pneumothorax not visible on the regular chest radiograph.Obese patients tend to have lower oxygen saturation on high flow oxygen delivery, and can be prone to hypoxia. If an advanced airway is required, this type of patient may present some significant challenges; obese patients can be at risk for compromised airway because the neck may be short and thick, and because excess adipose tissue increases the work of breathing when the patient is in a supine position.

Additionally, these patients may have an increased risk for aspiration caused by gastroesophageal reflux and increased abdominal pressure.4

Injury Patterns
Several studies suggest that injury patterns among obese trauma patients show increases in torso, lower extremity injuries, pelvic fractures and pulmonary injuries, with a decrease in head injuries. Regardless of the patterns of injury, mortality from blunt trauma was found to be higher (42%) among obese individuals than normal-weight persons (5%). The increase in mortality is directly related to complications resulting from the trauma. 5

Special Equipment
A critical consideration for the obese trauma patient is adequate availability of special equipment, both in the pre-hospital and ED environments. Specifically, stretchers and gurneys that can handle patients weighing more than 250 kg and ambulances wide enough to allow for care in the ambulance. Upon arrival to the emergency department, the availability of bariatric equipment for assessment purposes, such as large-sized blood pressure cuffs, chairs, stretchers, and commodes are important for safe patient handling and preservation of dignity. Another consideration is the availability of appropriately sized CT scanners; whether the machine can accommodate a given patient may depend on the distribution of adipose tissue.

Institutional and community pre-hospital planning is important for the coordination of care for the bariatric population in general. In the case of trauma, rapid assessment and intervention facilitated by planning can improve patient outcomes.

References

1. World Health Organization. (2015, January). Retrieved November 9, 2015, from Media Fact Sheet: http://www.who.int/mediacentre/factsheets/fs311/en/

2. Nelson, J. B. (2012). Obese trauma patients are at increased risk of early hypovolemic shock: a retrospective cohort analysis of 1,084 severely injured patients. Critical Care, R77.

3. Winfield, R. D., Delano, M. J., Lottenberg, L., Cenden, J. C., Moldawer, L. L., Maier, R. V., & Cuschieri, J. (2010). Traditional resuscitative practices fail to resolve metabolic acidosis in morbidly obese patients after severe blunt trauma. Journal of Trauma, 317-30.

4. VanHoy, S. N., & Laidlow, V. T. (2009). Trauma in Obese Patients: Implications for Nursing Practice. In Critical Care Nursing Clinics of North America (pp. 377-389).

5. Ryb, G. E., & Dischinger, P. C. (2008). Injury severity and outcome of overweight and obese patients after vehicular trauma: a crash injury research and engineering network (CIREN) study. Journal of Trauma, 406-11.

Lisa Wolf is director, Institute for Emergency Nursing Research at the Emergency Nurses Association.

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