Obesity describes a body weight that is much greater than what is healthy for that person. In health care the body mass index (BMI), weight in kilograms divided by height in meters squared is used to quantify obesity. People with a BMI between 25 kg/m2 and 30 kg/m2 are considered overweight, people with a BMI greater than or equal to 30 kg/m2 are considered obese, while anyone who is more than 100 pounds overweight or who has a BMI greater than or equal to 40 kg/m2 is considered morbidly obese. Thus for an adult who is 5 ‘ 9” tall, a body weight of 203 lbs or more would be classify them as obese. Per the CDC “in 2009, only one state (Colorado) and the District of Columbia had a prevalence of obesity less than 20%, 33 states had a prevalence equal to or greater than 25% and nine of these states had a prevalence of obesity equal to or greater than 30%”, and the numbers continue to grow. The rate of obesity growth is even higher in our children. Today addressing obesity is one of the highest health care priorities but until significant strides are made, we will encounter bariatric patients on a daily basis.
Health Issues Related to Obesity
It has been well established that obesity is a major risk factor for numerous diseases and is associated with multiple adverse health conditions specific to obesity. In one study, obesity had more negative health effects than smoking, alcohol abuse, and poverty. The most common health risks are diabetes mellitus, hypertension, and hyperlipidemia. All of these are associated with an increased incidence of vascular disease. Depending on which blood vessels are affected, there can be an increase in strokes, cardiac disease, congestive heart failure, and peripheral edema and ulceration. In addition to congestive heart failure, elevated intra-abdominal pressure and restricted lung volumes compromise respiration. Furthermore, adequate respiration is often limited due to obstructive sleep apnea. Other associated conditions include gallbladder and liver disease, osteoarthritis, gout, elevated cancer risk, skin infections and decubitus ulcers. Overall, obesity has the potential to negatively impact every organ system.
Bariatric Surgery and Complications
When all other options have failed, morbid obesity may be treated with surgery. The actual procedure varies depending on patient preference and local surgical expertise. The most common procedures include gastric bypass, gastric sleeve, and gastric banding (Lap-Band). These can be performed either laparoscopically, or with an open incision. The gastric bypass involves creating a small gastric pouch out of the upper part of the stomach and esophagus, and connecting it to the proximal jejunum. The remnant of the stomach, along with the duodenum, is connected to the jejunum in order to preserve function of the liver and pancreas. With the gastric sleeve procedure, the greater curvature of the stomach is resected. The remaining portion is stapled, leaving a narrower stomach. Gastric banding is performed by placing an adjustable band around the proximal portion of the stomach. The band limits the expansion of the stomach.
Complications of these procedures which may require EMS intervention are divided into early and late complications. Early complications are those which occur within the first month after surgery, such deep venous thrombosis, pulmonary embolism, wound infection, sepsis, and gastrointestinal bleeding. These procedures also carry the risk of a stomach or bowel leak from a staple line or an anastomosis. With gastric banding, patients can develop an obstruction at the site of the banding.
Late complications occur after the first month. With all of these procedures, patients can develop obstruction from strictures, hernias, or hardware complications. Gallstones frequently form after a considerable weight loss. They are such a frequent complication that the gallbladder is often removed prophylactically as part of the initial operation. Gastric bypass has a significant late risk of ulcers near the area of the union of the stomach and jejunum. Unique to the banding procedure, a hardware malfunction may develop which may result in symptoms of a leak, infection, or obstruction. Thus undifferentiated abdominal is a common dispatch complaint.
Evaluation of the Bariatric Patient
Evaluation of obese patients presents many challenges to healthcare providers. They are at risk for a multitude of health problems, and it can be difficult to determine the nature of complaints. Excess body mass can also make it difficult to determine what organ system is affected. Chronic medical problems present the challenge of an unknown baseline of illness which makes determining the current state of an acute illness problematic. Many complaints are often vague in nature. Neuropathy, commonly seen in diabetic patients, makes pinpointing the location of pain more difficult for the patient and health care provider. Vague complaints such as “I don’t feel well” or “something’s not right” may be the all a patient can tell you even though they may be progressing to serious infection or cardio-respiratory compromise. These patients may have complex medical history involving a myriad of comorbid conditions, surgeries and medications. The information needed is the same as for any other patient: signs/symptoms, allergies, medications, past medical and surgical history, last oral intake, and events leading to present illness.
Initial assessment is the same as for any other patient: ensure scene safety, take BSI precautions, and assess airway patency, breathing mechanics, and adequacy of circulation. Although this initial survey is conducted as for other patients, the bariatric or obese patient will present unique challenges to the provider in completing this assessment. The airway assessment is complicated by profound effects of obesity on airway anatomy and pulmonary physiology. Obese patients are at higher risk of hypoxemia and hypercapnia at baseline, as they have less efficient respiratory muscles evidenced by increased oxygen consumption during exercise compared to non-obese patients, giving them less reserve than other patients. Obese patients have diminished lung capacity from decreased chest wall compliance and increased abdominal cavity contents. There is decreased functional capacity with increasing BMI resulting in smaller oxygen reserve, as well as increased oxygen consumption and carbon dioxide production from excess metabolic activity. Both these issues mean EMS professionals must be alert for a potential rapid decline in respiratory status. Excessive skin and adipose tissue around the cheeks, lower jaw, neck and thorax can place extra pressure on the tongue and airway. Many obese patients suffer from sleep apnea caused by partial obstruction of the glottic opening by soft tissue. Evaluating the head and neck, as well as asking the patient about a sleep apnea diagnosis or need for CPAP/BiPAP during sleep, can help to predict a difficult airway. Breath sounds may be difficult to auscultate and sound distant upon exam. Heart sounds present the same problem. If possible, palpate a peripheral pulse while listening for heart sounds. This may help the provider to hear the faint heart sounds. Increased neck girth and soft tissue sometimes make the assessment of jugular venous distension impossible.
The abdominal exam in obese patients is complicated by the loss of the usual anatomic landmarks. In patients who have undergone bariatric surgery even more so. Obese patients have increased intraabdominal pressure which increases the incidence of hiatal hernia and gastro esophageal reflux disease. Palpation of deep structures will be extremely difficult and physical exam signs of intraabdominal pathology may be unreliable. For example, the amount of adipose tissue between the abdominal cavity and the skin may delay the presence of Cullen’s or Grey-Turner signs even when significant intraabdominal hemorrhage is present.
Treatment of bariatric patients, like all others, begins with the airway. Positioning is of utmost importance when managing the airway of an obese patient, as they may have some degree of airway obstruction or compromise at baseline. If the patient is conscious and not suspected to have sustained trauma to the spinal cord allow them to assume a position of comfort, such as Fowler’s position (sitting upright or slightly reclined, legs bent or straight). If the patient is unconscious and/or not maintaining his airway and cervical injury is suspected then the usual immobilization precautions must be taken. Take care not to compress the airway or major blood vessels in the neck with a collar that is too tight.
When preparing to assume control of the airway, positioning is paramount. As obese patients do not tolerate apnea well, repositioning after a failed attempt at establishing an airway can have severe consequences. Before any obese patient without suspicion of cervical injury is placed in a supine position the provider should place blankets, towels, etc under the head, neck and shoulders to create the “ramped up” position. The external auditory canal should be parallel with the sterna notch. A BMI greater than 26 is a predictor of difficulty in maintaining adequate oxygen saturations with bag mask ventilation. Oropharyngeal and nasopharyngeal airways should be utilized to optimize oxygenation and ventilation in obese patients. Whenever possible, a 2-person technique should be utilized with a two handed bilateral jaw thrust. This also will increase the likelihood of achieving good mask seal, which is essential to generate the inspiratory pressure needed to overcome increased lung compliance secondary to poor chest wall compliance, decreased diaphragmatic excursion and redundant supraglottic tissue. When the decision is made to intubate an obese patient, awake intubation should be considered as loss of muscle tone with sedative and paralytic drugs can cause complete occlusion of the patient’s airway. Always have a backup plan for the “can’t intubate, can’t ventilate” situation. Remember that extra neck soft tissue will complicate a surgical airway. Landmarks may be difficult to identify, however cricothyroidotomy has been shown to be technically feasible even in patients with difficult neck anatomy secondary to obesity. A supraglottic device such as an LMA is a great tool to have at hand, it may be effective for ventilation or as a rescue device after a failed attempt at intubation. Knowing what is available in your airway bag and familiarizing yourself with the equipment must be done prior to the need arising. A tracheal tube introducer (Bougie) is another excellent tool to facilitate securing the airway of an obese patient in the prehospital setting. It is most helpful in situations where there is a restricted view of the glottis, or only the epiglottis/arytenoids are visualized.
Once endotracheal intubation has been achieved the challenge of confirmation arises. Due to issues mentioned earlier, clinical test alone may not be sufficient to confirm placement. Auscultation of lungs and gastric fields may be limited; pulse oximetry may be inaccurate due to the same issues of excessive soft tissue. Capnography, co2 detectors and esophageal detectors can help increase the confidence in placement. Once the patient has been successfully intubated ventilation is required. It may be tempting to overestimate lung volume based on body size in an obese patient, but care must be taken to prevent excessive plateau pressures that can cause lung injury. Positive end expiratory pressure can be beneficial to oxygenation in obese patients. Using 10 cm H2O improves respiratory mechanics and oxygenation in obese patients compared to nonobese patients. This acts to recruit alveoli and prevent atelectasis when ventilating. However, excessive pressure can negatively affect cardiac output, so care must be taken when using this technique.
Circulation is another key aspect in the evaluation and treatment of obese patients and the evaluation is made more difficult due to the obesity. At baseline obesity places increased stress on the heart, requiring increased cardiac output, even at rest, to perfuse the additional tissue. Due to the increased cardiac demand, increased peripheral resistance, increased blood volume, and general deconditioning, obese patients have higher basal heart rates. Auscultating blood pressures may be difficult even with appropriately sized cuffs. ECGs may be less reliable secondary to distance of the leads from the heart. Consideration of cardiac disease must be considered in obese patients who are younger than what is normally considered an age associated with risk for myocardial infarction or hypoperfusion.
The obese patient will also present challenges to EMS professional providing CPR. Proper positioning to perform effective CPR may be difficult. Ensuring adequate depth of compressions and chest recoil may be extremely difficult. A second provider palpating for pulses during compressions can help determine if they are effective. CPR assist devices may not be capable to accommodating obese patients and should be considered second line to traditional CPR by two trained providers. Lastly, even with effective CPR, obese patients tend to have worse outcomes following resuscitation.
In part two of this series we will discuss additional issues related to the immobilization, transport, triage, and treatment of the obese patient as well as issues EMS professionals themselves may have from working with the obese, such as workplace safety and injuries.
To read Part 2 of this series, click here.
Zerah F, Harf A, Perlemuter L, et al. Effects of obesity on respiratory resistance. Chest. 1993; 1470-1476.
Dargin J, Medzon R. Emergency Department Management of the Airway in Obese Adults. Ann Emerg Med. 2010; 56:95-104 2009.
Adams JP, Murphy PG. Obesity in anesthesia and intensive care. Br J Anaesth. 2000;85:91-108.
Cartagena R. Preoperative evaluation of patients with obesity and obstructive sleep apnea. Anesthesiol Clin North Am. 2005; 23:463-478.
Langeron O, Masso E, Huraux C, et al. Prediction of difficult mask ventilation. Anesthesiology. 2000; 92:1229-1236.
Rehm CG, Wanek SM, Gagnon EB, et al. Cricothyroidotomy for elective airway management in critically ill trauma patients with technically challenging neck anatomy. Crit Care. 2002; 6:531-535.
Pelosi P, Ravagnan I, Giurati G, et al. Positive end-expiratory pressure improves respiratory function in obese but not in normal subjects during anesthesia and paralysis. Anesthesiology. 1999; 91:1221-1231.