Airway Management In An Obese Patient

Managing the airways is one of the basic elements of patient care. It requires continuous training in maneuvering and using devices that enable adequate and safe ventilation.

The knowledge of the problems of the respiratory tract includes anatomy, causes of structural anomalies and the methods of its penetration. Currently, persistent difficulties in using this procedure result in complications and mortality associated with anesthesia. This is why proper airway management is so important.

Obesity and overweight are the build up of excess fat in the body which can be harmful to your health. They are risk factors for many chronic diseases such as diabetes, cardiovascular disease and cancer.

Unfortunately, at present there is often little attention paid to the diagnosis of so-called difficult airways in obese people. The study of abnormal airways divided them into two groups: congenital and acquired difficult airways. The latter case may occur in morbid obesity.

Accumulation of fat in a morbidly obese patient can cause difficulties in laryngoscopy and intubation. Therefore, it is necessary to assess the amount of excess body fat, both internal (mouth, throat, abdominal cavity) and external (breast, neck, chest wall and abdomen).

It then considers a number of morbidly obese characteristics that need to be considered in airway management. The key is to anticipate difficulties and execute a good action plan.

The anatomy of obese patients makes airway management difficult

In an obese patient, both fat distribution and weight matter are important. However, for the treatment of the respiratory tract in these patients, the distribution of fat is more important than the weight of the patient.

Nuclear magnetic resonance imaging investigated fat distribution in morbidly obese patients with and without obstructive sleep apnea syndrome. Obese patients with sleep apnea have been shown to have more fat in the areas surrounding the pharynx and larynx.

Thanks to these results, it was possible to explain why managing the airways in some patients is easy and in others it is difficult. The occipital position of the fat can reduce the stretching ability of the neck, making laryngoscopy difficult.

Obese patients physiology and airway management

Various studies have been conducted which show that obese patients have increased muscle tone. By reducing this tension during anesthesia, the airway can be blocked, making it difficult to ventilate with a face mask.

Moreover, in obese subjects, functional reserve capacity as well as total lung capacity are reduced. Consequently, the consumption of oxygen increases. Therefore, they are predisposed to desaturation after induction of anesthesia.

Pharmacology as a way to manage the airways

One of the keys to safety when treating the respiratory tract of obese patients is therefore to achieve the appropriate depth of anesthesia before starting mask ventilation.

Conversely, attempting to ventilate a patient with superficial anesthesia can lead to false diagnoses of ventilation failure.

Most of the drugs used for induction are lipid soluble. For this reason, the initial distribution in the treatment effect range may be low.

Therefore, for obese patients, the use of adjusted doses is recommended, rather than the doses for those of the ideal weight.

Difficult airways

Currently, the percentage of obese patients with difficult airway syndrome is as high as 15.8% compared to 5.8% in the normal population.

A Body Mass Index (BMI) greater than 30 and sleep apnea are factors that lead to difficult airway management. However, this has not been shown to hinder intubation.

There are other studies that use more specific markers, such as the Difficult Intubation Scale. These studies confirm that obese patients are more likely to have difficult airways.

Aspiration and preoperative fasting

Obese patients usually have a longer gastric emptying time. However, it was not observed that they experienced more aspiration or gastroesophageal reflux disease.

Therefore, additional methods of applying fasting or bronchial aspiration are not recommended if any airway management technique is to be used.