Obese patients and managing them in surgery has always been a challenge for the whole clinical team, especially for the surgeon and anaesthetist. The special circumstances of obese patients require adapting teams and techniques, from the physical facilities of the surgery itself to the surgical and anaesthetic techniques used.
Currently, the classification of obesity is made using the BMI (Body Mass Index), which is the result of dividing the patient’s weight in kg by their height squared in metres. From this we obtain a measurement in kg/m2. WHO criteria for classifying the different levels of obesity are as follows:
|Level||BMI kg/m2||Comorbidities risk|
|Normal weight||18.5 – 24.9||Medium|
|Overweight||25 – 29.9||Increased|
|Class 1 obesity||30 – 34.9||Moderate|
|Class 2 obesity||35 – 39.9||Severe|
|Class 3 obesity (morbid)||>40||Extreme|
As well as difficulties in handling the patient due to the weight and body size, obese patients, depending on their level, usually present comorbidities (more serious the greater the level of obesity) that must be taken into account when planning the surgery. For example, it is common for these patients to suffer from high blood pressure, diabetes mellitus, sleep apnoea/hypopnoea syndrome (SAHS), dyslipidaemia, arteriosclerosis, cardiovascular diseases and musculoskeletal dysfunctions etc. All of this can mean a level of chronic systemic inflammation and a prothrombotic state. As well as the assessments made by the surgical team in planning the operation, the anaesthetist during the previous consultation will identify and assess all of these factors and decide if any preoperative treatment is necessary (for example, an antithrombotic to reduce the risk of blood clots forming during the operation), as well as evaluating the possible difficulties for the airway, a frequent complication in obese patients.
Intravenous anaesthesia in obese patients
Propofol is one of the most popular drugs used to induce and maintain total intravenous anaesthesia (TIVA) in obese patients, often combined with other drugs. If the surgical team chooses to use TIVA once the patient’s characteristics have been analysed, the anaesthetist will use a pharmacokinetics model of target controlled infusion (TCI) to ensure that the tissue concentration of propofol and other drugs used in the anaesthesia is correct, something that is a challenge in obese patients due to their special circumstances.
In fact, if any of the classic TCI models for propofol are used, the anaesthetist must make additional calculations to adjust the dose, as in many cases they have not been designed for obese patients. To avoid this, the arcomed Chroma pumps exclusively offer the Cortínez-Sepúlveda model for the use of propofol in obese patients (up to 250kg) which saves time in calculations and offers actual concentrations that are more adjusted to those predicted.
At arcomed we work every day to meet the needs of health professionals in the field of intravenous infusion, including in the most complex cases.