By Sandra Schmid and Elaine Philipson: Survival Flight Nurses
Scene call
Minivan stopped with left turn signal on, waiting to make the turn, when they are struck from behind by a vehicle going 55 mph. This pushes them into the oncoming traffic passenger side first toward the full sized truck going 55 mph. Our Patient is front seat restrained passenger involved in this accident.
35-year-old female restrained passenger of minivan, airbags deployed, pin-in motor vehicle crash (MVC) with extrication in excess of 20 minutes. She is alert and oriented after a brief loss of consciousness. She has obvious fractures of the right radius and ulnar bones, right femur and right ankle. Her medical history is unknown. She is 5’4” and 164kg. At this height and weight, she is considered to have a body mass index (BMI) >60 (calculating out to BMI of 61.8), putting her in class III extreme morbid obesity. The medical condition of extreme morbid obesity complicated all aspects of care in this trauma patient.
The Obesity Medicine Association (OBA) has defined obesity as “a chronic, relapsing, multi-factorial, neurobehavioral disease, wherein an increase in body fat promotes adipose tissue dysfunction and abnormal fat mass physical forces, resulting in adverse metabolic, biomechanical, and psychosocial health consequences.”
Starting at 25.0, the higher your BMI, the greater is your risk of developing obesity-related health problems. Per the CDC guidelines these ranges of BMI are used to describe levels of risk:
- Overweight (not obese), if BMI is 25.0 to 29.9
- Class 1 (low-risk) obesity, if BMI is 30.0 to 34.9
- Class 2 (moderate-risk) obesity, if BMI is 35.0 to 39.9
- Class 3 (high-risk) obesity, if BMI is equal to or greater than 40.0
Extrication
The patient’s body mass complicates the ability to manipulate the damaged vehicle from around her and the amount of personnel needed to assist in extraction. A cervical collar has difficulty fitting related to the increased diameter of the neck. The dorsocervical adipose tissue inhibits full cervical immobilization causing the head to be positioned forward. A backboard was used to assist in lifting and moving the patient to the ambulance to await Survival Flight for transport to the closest level 1 trauma center. The use of the backboard was complicated by the width of the backboard related to the width of the patient. The firemen found it difficult to use handholds to lift. Extra boards were used horizontal to the backboard to lift and move the patient on the backboard.
Once on the backboard lying flat, the patient complained of shortness of breath (SOB). She was placed on oxygen via facemask at 15 liters / min. She continued with a high respiratory rate and shallow respirations. Patients with severe morbid obesity often complain of breathing restrictions when lying flat. Excess accumulation of adipose tissue on the chest wall and abdomen reduce lung compliance and functional residual capacity. Severe morbid obesity also can have an obstructive component related to increased collection of adipose tissue in the pharyngeal area causing an increased pharyngeal collapsibility through mechanical effects on pharyngeal soft tissues. Preparations for intubation started related to the patient’s decrease in level of consciousness (LOC) and SOB.
Intubation
Prior to intubation, preoxygenation with high flow nasal cannula was initiated and continued during intubation to assist with the rapid deoxygenation expected in obese patients. Obesity can cause increased risk factors and difficulty with intubation. Bag mask ventilation is complicated by increased adipose tissue of the face and pharyngeal area collapsibility with supine positioning. Functional lung capacity is exponentially related to BMI, resulting in reduction in total lung capacity (Salome, King, Berend 2009). Using increased PEEP to 10 cm H20 for bag mask assists during pre-oxygenation reduces atelectasis and increases time of apnea without hypoxemia by an average of one minute (Gray et al. 2018).
Evaluation of difficult airway was performed. Visual inspection showing the patient is obese. Evaluation using the 3-3-2 rule:
- The patients mouth opening was small < 3 finger widths
- The measurement of the mandible to the hyoid <3 but difficult to assess related to excess adipose tissue
- Thyromental distance is also difficult to assess related to excess adipose tissue.
The neck remains immobile in the c-collar and log roll precautions inhibit a “ramping” technique. The patient’s weight, personnel in the ambulance and working space inhibit a “reverse Trendelenburg.” A 30-degree reverse trendelenburg or a 25-degree head up position has been shown to improve pre-oxygenation and safe apnea time in the morbidly obese (Grey et al 2018). Following a procedural TIME OUT, induction medications were administered, dosing per ideal body weight (not estimated current weight) and the patient was orally intubated using video laryngoscopy without difficulty once the crew was able to place the laryngoscope into the airway. The use of a short handled scope is often recommended due to difficulty with mouth opening and distance between mouth the chest wall adipose tissue.
Post Intubation
The patient was ventilated with a resuscitation bag post intubation with 100% oxygen and a PEEP of 10 mmHg. On repeat primary survey, it was noted that the pupils were unequal and the patient was hypotensive with a BP 77/52. Crystalloid fluid resuscitation was increased to wide open on pressure bags and hypertonic saline was initiated for a presumed increase in intracranial pressure. The patient was transported to the waiting aircraft and loaded with the assistance of 8 fire fighters. Once loaded in the aircraft, the crew initiated aggressive blood product resuscitation to include liquid plasma and packed red blood cells (PRBC). Obtaining an accurate BP reading utilizing the largest cuff that we had was challenging. Both vascular access (IV) sites were antecubital. While trying to obtain a BP on the upper arm utilizing the large adult cuff, one of the IV’s was displaced by pressure of the inflating cuff. We were unable to utilize the lower legs for BP readings due to possible fractures and were limited to one arm due to presumed radial fracture. Attempts were made to place additional peripheral IV’s but access was not obtained. Gaining peripheral intravenous access in a morbidly obese patient can be challenging and often delays resuscitation. Intraosseous cannulation is another vascular access option. This was not attempted in transport. It is noted in the literature that clinicians resuscitating morbidly obese patients should use appropriately sized cuffs and that these patients may have a greater need for invasive blood pressure monitoring in order to provide accurate data.
The patient was placed on the ventilator enoute to the trauma center. Because of a heavy, non-compliant chest wall, initial tidal volumes were set at approximately 8ml/kg- ideal body weight.
Enroute to the nearest trauma center, the patient was resuscitated with 2 units of liquid plasma and 2 units PRBC’s during the 10-minute flight. Resuscitation efforts were targeted to mentation since blood pressure data was unreliable at best (the only BP reading obtained was 59/29). Once the patient began reaching for her endotracheal tube, fentanyl was given for pain management and sedation.
Upon arrival to the trauma center, BP readings and vascular access was attempted. Intraosseous access was unsuccessful when attempted in the humeral head. The yellow (long) needle was not long enough to engage the bone. Aggressive resuscitation efforts were continued. Her initial hemoglobin was 9.5 g/dl but quickly dropped to 7.6 g/dl. It was reported as low as 6.0 g/dl during the first 24 hours of her hospitalization. Her initial lactate was 10.7 mmol/L and arterial blood gas (ABG) included a pH of 7.12 a PaCO2 of 53 mmHg, a PaO2 of 205 mmHg and a bicarbonate level of 16.5 mEq/L. Gaining central vascular access was difficult despite using ultrasound technology and delayed her move out of the ED. She received 7 units of PRBCs, 9 units of liquid plasma, a five-pack of platelets and 3 units of cryoprecipitate.
Her “official” catalog of injuries included a right frontal subdural and subarachnoid hemorrhage, bilateral superior and inferior pubic rami fractures, right sacroiliac joint disruption, traumatic abdominal wall hernia, abdominal hematoma, right humeral fracture, right distal radius fracture, right ankle syndesmosis disruption, right distal fibula fracture, L5 transverse process fracture and a sacral fracture. She spent 17 days in intensive care and eventually was discharged to a rehabilitation center specializing in the morbidly obese.
Take Home Points:
- Care of the critically injured, morbidly obese patient poses grave challenges to routine management strategies and assessment parameters.
- Peripheral vascular access will be challenging and intraosseous vascular access might be next to impossible. Ultrasound-guided options, while quickly becoming mainstay therapy in most ED’s may or may not yet be available in critical care transport. If at all able, consider implementing this in your program.
- Non-invasive blood pressure monitoring may be equally difficult to obtain. Consider an invasive option (not withstanding technical and logistical challenges on scene with this “critical care” skill) if within your scope of practice. A blood pressure might not be that crucial if you are still able to assess other perfusion parameters such as level of consciousness, skin color / temperature, capillary refill time and waveform capnography (EtCO2).
- Common management challenges associated with the morbidly obese includes increased difficulty with airway management and ventilation. Utilize video laryngoscopy whenever possible and understand that “standard” ventilator settings may not work with the morbidly obese as moving the weight of the lungs and additional adipose tissue in order to ensure adequate minute ventilation will be necessary. This could necessitate increased pressures / volumes that would normally be considered higher than normal.
For additional considerations, visit the Life in the Fast Lane blog space at:
This particular post provides crucial considerations to the morbidly obese trauma patient in a succinct “bullet point” format.
References
Berrios, L. A. (2016). The ABCDs of managing morbidly obese patients in intensive care units. Critical Care Nurse, 36(5), 17-26.
Gray, S., & Dieudonne, B. (2018). Optimizing care for trauma patients with obesity. Cureus, 10(7).
Maged, S., & Straker, T., MD. (2020, August 2). Airway Management in the Morbidly Obese Patient. Retrieved October 27, 2020, from https://www.anesthesiologynews.com/Review-Articles/Article/07-20/Airway-Management-in-the-Morbidly-Obese-Patient/59064
Nickson, C. (2019, April 01). Obesity and Trauma • LITFL • CCC Trauma. Retrieved October 27, 2020, from https://litfl.com/obesity-and-trauma/
Salome CM, King GG, Berend N. Physiology of obesity and effects on lung function. J Appl Physiol (1985). 2010 Jan;108(1):206-11. doi: 10.1152/japplphysiol.00694.2009. Epub 2009 Oct 29. PMID: 19875713.