Specific issues in anesthesia of obese patients

    Authors

    Abstract

    The treatment of obesity requires an interdisciplinary approach that includes a wide range of dietary measures, changes in life habits, physical activity, and the use of various medications. Most of these measures, however, only result in a limited and temporary loss of body mass, which is one of the reasons for an increasing tendency towards resorting to surgical treatment or bariatric surgery. Bariatric procedures change the capacity and anatomy of the digestive system and are recommended as treatment for obesity in persons with a BMI above 40 kg/m2 or persons with a BMI above 35 kg/m2 with concomitant diseases such as arterial hypertension, diabetes, or cardiorespiratory disorders.

    Keywords

    KLJUČNE RIJEČI: pretilost, anestezija, kirurško liječenje, obesity, anesthesia, surgical treatment

    DOI

    https://doi.org/10.15836/ccar2017.319

    Full Text

    ## Introduction “Corpulence is not only a disease itself, but the harbinger of others” is a claim that was already made and written down by Hippocrates a long time ago. According to the definition of the World Health Organization, obesity is a state that occurs due to excessive depositing of body fat with the consequent hazardous effect on health. Obesity is now one of the leading and most common health problems in the world. It is usually defined using body mass index (BMI), which represents the ratio of body mass in kilograms and body height expressed in square meters. Obesity represents a risk for the development of many chronic diseases such as diabetes, arterial hypertension, cardiovascular diseases, restrictive lung diseases, obstructive sleep apnea, degenerative joint diseases, and malignant diseases. In addition, obesity causes a number of socioeconomic and psychic disorders and significantly reduces quality of life and expected lifespan ( 1 ). ## The effect of obesity on organ systems and the specificities of anesthesia Obese persons have reduced lung function as a consequence of several different factors. The accretion of fat tissue in the chest and abdominal cavities causes pressure on the diaphragm and the chest, which results in reduced elasticity of the lungs and chest wall as well as reduced synchronicity between the lungs and chest when breathing in. This leads to reduced lung volume and the overburdening of inspiratory muscles that deteriorate with BMI increase. The reduction in total lung elasticity leads to the reduction of functional residual capacity (FRC), impaired gas exchange, and significant hypoxia with possible complications ( 1 - 3 ). Respiratory disorders that should be mentioned include hyperventilation syndrome and obstructive sleep apnea (OSA), which affects more than 5 % of pathologically obese persons ( 2 ). OSA is defined as upper airway obstruction during sleep that leads to a drop in the oxygen saturation of hemoglobin and frequent waking up. The typical clinical picture of OSA is characterized by short episodes of stopped breathing occurring more than five times per hour or more than 30 times during the night. These patients usually have increased amounts of fat tissue in the wall of the pharynx, which results in increased compliance of the pharynx and a greater likelihood of the collapse of the soft wall of the pharynx, which in turn leads to a partial or complete obstruction of the upper airways and thus a unique challenge for the anesthesiological approach during a surgical procedure for the treatment of pathological obesity ( 2 ). As a consequence of long-term unrecognized OSA, hypoventilation syndrome can occur, which is a state of gradual reduction of the sensitivity of the breathing center in the brain. The clinical picture is dominated by somnolence, dyspnea, and hypoxemia with the consequent polycythemia, cyanosis, and plethoric appearance ( 1 ). ## Influence on the heart and circulatory system Cardiovascular diseases are the dominant causes of mortality and morbidity in pathologically obese persons. The incidence rises significantly with a BMI >35kg/m 2 . Arterial hypertension is the most common disease associated with obesity. Mild and moderate hypertension can be found in over 60 % of patients with obesity, whereas a severe level of hypertension is present in 5-10 % of pathologically obese persons ( 1 ). Hypertension results from the interaction of genetic predispositions and hormonal, renal, and hemodynamic factors. Obese persons have increased risk of ischemic heart disease, heart arrhythmias, and the development of myocardiopathy. It is believed that one of the reasons for the development of arrhythmias is the infiltration of fat cells into the myocardium, which generally happens in the right ventricle and can lead to disorders in the circulatory system of the heart. ## Influence on the digestive system and liver function Although it is believed that the stomachs of obese persons empty faster, most likely due to the larger volume of the stomach itself, they almost always have gastric residual, increased pressure in the abdominal cavity, and increased risk of aspiration of gastric content during the induction of anesthesia ( 4 ). Additionally, positive pressure ventilation during anesthesia induction can lead to stomach bloating and regurgitation of stomach contents. In obese patients it is therefore recommended to apply prokinetic medication, H2-receptor blockers, or proton pump inhibitors before the induction of anesthesia to reduce the consequences of the aspiration of acidic gastric contents ( 5 ). More than 90 % of obese persons manifest histological changes due to fat infiltration in liver cells. Twenty percent of patients show signs of severe and diffuse hepatic steatosis, while 20–30 % of patients without clear liver changes present with elevated liver enzyme values. Among these, increased activity of alanine aminotransferase is the most common. Despite abnormal indicators of liver function, there is no clear association between routine liver function tests and liver capacity for drug/anesthetic metabolism ( 4 ). ## Influence on renal function Due to the increased blood flow through the kidneys in pathologically obese persons, the glomerular filtration rate and renal clearance of drugs are increased as well ( 6 ). The increase in glomerular filtration that can reach as much as 40 % in pathologically obese person’s cause’s glomerulopathy coupled with obesity, i.e. proteinuria, which is the most common renal function disorder in these patients, with stabilization of renal function occurring after surgical treatment ( 6 - 8 ). ## Preoperative evaluation and preparation of obese patients Preoperative evaluation of obese patients for a surgical procedure does not differ from that in patients with normal body weight, and depends on the overall health status, concomitant diseases, and the surgical procedure to be performed. In patients with concomitant diseases, the processing is expanded depending on the clinical status of the patient and includes examination by a cardiologists, ultrasound and cardiac stress tests, examination by a pulmonologist, arterial blood gas tests and spirometry, as well as comprehensive endocrinological examination. Patients with a diagnosis of OSA and hyperventilation syndrome who are being treated with continuous or biphasic positive pressure (CPAP masks) should be reminded to continue their treatment until admission to the hospital. The application of a CPAP mask should be continued as soon as possible in the postoperative course. Preoperative preparations also include mandatory application of low molecular weight heparin with mechanical thromboprophylaxis that includes the use of elastic compression due to the significantly increased risk of thromboembolic incidents in obese patients ( 2 , 4 ). Due to initially disordered lung function and reduced oxygen saturation in arterial blood, obese persons have an increased risk of complications during induction of anesthesia ( 5 ). As a consequence of excessive fat tissue accretion not only externally around the neck, chest cavity, and abdominal wall but also internally in the mouth and pharynx, establishing the airway and endotracheal intubation can be more difficult, especially in the supine position on the operating table. To prevent problems with intubation and airway management, it is important to properly adjust and position the obese patient on the operating table. Best visibility for endotracheal intubation is achieved by raising the upper part of the body by 25–30 % with the placement of a pillow under the head and neck, so as to line up the outer ear canal with the sternum (the so-called ramp position). This achieves the best visibility of the airways. Due to the rapid decrease in oxygen saturation of arterial blood, an oxygen mask should be applied in obese patients before induction of anesthesia. The combination of preoxygenation (administering oxygen through a mask before induction of anesthesia) and the elevated position of the upper body enable the physicians to maintain arterial blood saturation at 100 % within a few minutes in the greatest number of cases. Applying positive end-expiratory pressure (PEEP) of 10 cm H 2 0 during preoxygenation and induction of anesthesia prolong the time for intubation before decrease blood oxygen saturation occurs ( 5 - 7 ). ## Choice of anesthesia in obese persons Due to increased volume of distribution, extended elimination half-life, increased glomerular filtration rate, and fat infiltration of the liver, the biotransformation of many anesthetics is altered ( 2 ). Application of lipophilic anesthetics such as barbiturates, benzodiazepines, and some opioids is recommended at a higher dose because of increased volume of distribution ( 2 ). Propofol and remifentanil are the exception. Determining the dose of propofol should be adjusted to the age and ideal body weight of the patient, since dosing based on total body weight (TBW) can cause serious depression of the cardiocirculatory system. The volume of distribution for less lipophilic drugs such as muscle relaxants is not significantly altered, so these drugs can be dosed based on ideal body weight, or, more precisely, lean body mass. Succinyl cholinesterase activity is reduced in obese persons, and dosing should be based on total body weights. Opioids are extremely lipophilic, so the initial dose should be based on TBW, but the maintenance doses must be reduced due to the increased sensitivity of obese patients and the possible development of respiratory depression. Among volatile anesthetics for the maintenance of anesthesia, anesthetics with lower solubility in lipids should be used because they allow rapid achievement of the appropriate depth of anesthesia and faster awakening and recovery after the surgical procedure is complete. Potent volatile anesthetics such as sevoflurane, desflurane, and isoflurane are safe for the maintenance of anesthesia ( 4 ). During anesthesia, it is recommended to use controlled mechanical ventilation with a greater tidal volume of 15–20 mL/kg, breathing frequency of 12–14 /min, and the application of PEEP, with the goal of achieving better oxygenation and a lower incidence of atelectasis. Mandatory monitoring during the surgery includes an electrocardiogram, non-invasive pressure measurement, pulse oximeter monitoring, and capnography. In high risk patients, an arterial line is also introduced to continuously measure arterial pressure and determine blood gas, and a pulmonary catheter is used in patients with pulmonary hypertension. Regional anesthesia has also become increasingly popular in obese patients ( 2 ). Although significant technical difficulties can occur during anesthesia itself, regional anesthesia has certain advantages in comparison with general anesthesia, which include avoiding potential issues with establishing airflow, avoiding drugs that can cause cardiorespiratory depression, reducing postoperative nausea and vomiting, and better postoperative pain management ( 2 , 5 ). Monitoring during a surgical procedure for patients under regional anesthesia is the same as in patients under general anesthesia ( 4 , 5 ). Enhanced monitoring is also necessary during early postoperative course. This includes monitoring of SaO 2 and administering oxygen through a mask or nasal catheter, blood pressure and diuresis monitoring, and application of continuous positive airway pressure therapy (CPAP) in patients with OSA ( 2 ). Appropriate analgesia is also important since it prevents hypoventilation, secretion retention, and the development of pneumonia. The use of patient-controlled intravenous analgesia or thoracic epidural analgesia is recommended, depending on the type of surgical procedure ( 4 , 5 ). ## Surgical procedures in the treatment of pathological obesity Regarding issues associated with obese patients, it is important to note that surgical procedures are being performed today with the express goal of treating pathological obesity. Treating obesity requires a multidisciplinary approach that includes a wide range of dietary measures, changes in life habits, physical activity, and the use of various medications. Most of these measures, however, only result in a limited and temporary loss of body mass, which is one of the reasons for an increasing tendency towards resorting to surgical treatment or bariatric surgery. Bariatric procedures change the capacity and anatomy of the digestive system and are recommended as treatment for obesity in persons with a BMI above 40 kg/m 2 or persons with a BMI above 35 kg/m 2 with concomitant diseases such as arterial hypertension, diabetes, or cardiorespiratory disorders. There are a number of bariatric surgical procedures, two of which are most commonly performed ( 7 , 8 ). Adjustable gastric bands are placed around a part of the stomach immediately below the cardia, creating a small reservoir about 25 mL in volume that quickly fills up with food and sends an »earlier« message of satiation to the brain, helping the patient stop eating. This method primarily reduces the intake of food, thus making it a restrictive method of treatment. The amount of food intake restriction is controlled by a circular balloon within a ring that can be filled with or emptied of water or air through a port placed in the abdominal cavity. After this surgical procedure, the patient can achieve a reduction in excess body weight of approximately 50 ± 28 % over 2 years ( 8 ). ## Gastric bypass The Roux-en-Y gastric bypass is the most common surgical procedure in bariatric surgery today and is considered the “gold standard” in the treatment of pathological obesity. This procedure creates a small reservoir in the stomach, which achieves the restrictive component of the procedure (reduced food intake), and since the greater part of the stomach and the whole duodenum are bypassed, there is a malabsorptive component to the procedure as well. Food absorption is significantly reduced due to the exclusion of the duodenum and a part of the small intestine from digestion and because food is redirected to the small intestine from a small part of the stomach. This type of surgical procedure is considered to be the most effective method of treating pathological obesity, resulting in a loss of excess weight of 55-77 % while effecting the recovery of previously disordered renal function due to obesity ( 8 ). ## Conclusion Pathological obesity is a systemic illness that affects a growing number of people every year and is associated with damage to almost all systems in the body, including the respiratory, renal and cardiovascular, gastrointestinal, and endocrine systems. Most measures applied in the treatment of obesity result in only limited and temporary loss of body mass, which is one of the reasons why the use of surgical treatment or bariatric surgery is becoming more widespread today. Obesity represents a risk during surgical procedures, but proper positioning of the patient and preoxygenation reduce the likelihood of failed intubation and desaturation in the patient during induction of anesthesia, allowing a long-term solution to obesity with the primary goal of preserving the health of the heart and kidneys ( 3 , 7 ).

    Cardiologia Croatica
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    Specific issues in anesthesia of obese patients

    Review Article
    Issue7-8
    Published
    Pages319-324
    PDF via DOIhttps://doi.org/10.15836/ccar2017.319
    KLJUČNE RIJEČI: pretilost
    anestezija
    kirurško liječenje
    obesity
    anesthesia
    surgical treatment

    Authors

    Višnja NesekFaculty of Medicine, Osijek, Croatia
    Adam*ORCIDFaculty of Medicine, Osijek, Croatia
    Damir VažanićORCIDFaculty of Medicine, Osijek, Croatia
    Ingrid PrkačinORCIDFaculty of Medicine, Osijek, Croatia

    Abstract

    The treatment of obesity requires an interdisciplinary approach that includes a wide range of dietary measures, changes in life habits, physical activity, and the use of various medications. Most of these measures, however, only result in a limited and temporary loss of body mass, which is one of the reasons for an increasing tendency towards resorting to surgical treatment or bariatric surgery. Bariatric procedures change the capacity and anatomy of the digestive system and are recommended as treatment for obesity in persons with a BMI above 40 kg/m2 or persons with a BMI above 35 kg/m2 with concomitant diseases such as arterial hypertension, diabetes, or cardiorespiratory disorders.

    Full Text

    ## Introduction “Corpulence is not only a disease itself, but the harbinger of others” is a claim that was already made and written down by Hippocrates a long time ago. According to the definition of the World Health Organization, obesity is a state that occurs due to excessive depositing of body fat with the consequent hazardous effect on health. Obesity is now one of the leading and most common health problems in the world. It is usually defined using body mass index (BMI), which represents the ratio of body mass in kilograms and body height expressed in square meters. Obesity represents a risk for the development of many chronic diseases such as diabetes, arterial hypertension, cardiovascular diseases, restrictive lung diseases, obstructive sleep apnea, degenerative joint diseases, and malignant diseases. In addition, obesity causes a number of socioeconomic and psychic disorders and significantly reduces quality of life and expected lifespan ( 1 ). ## The effect of obesity on organ systems and the specificities of anesthesia Obese persons have reduced lung function as a consequence of several different factors. The accretion of fat tissue in the chest and abdominal cavities causes pressure on the diaphragm and the chest, which results in reduced elasticity of the lungs and chest wall as well as reduced synchronicity between the lungs and chest when breathing in. This leads to reduced lung volume and the overburdening of inspiratory muscles that deteriorate with BMI increase. The reduction in total lung elasticity leads to the reduction of functional residual capacity (FRC), impaired gas exchange, and significant hypoxia with possible complications ( 1 - 3 ). Respiratory disorders that should be mentioned include hyperventilation syndrome and obstructive sleep apnea (OSA), which affects more than 5 % of pathologically obese persons ( 2 ). OSA is defined as upper airway obstruction during sleep that leads to a drop in the oxygen saturation of hemoglobin and frequent waking up. The typical clinical picture of OSA is characterized by short episodes of stopped breathing occurring more than five times per hour or more than 30 times during the night. These patients usually have increased amounts of fat tissue in the wall of the pharynx, which results in increased compliance of the pharynx and a greater likelihood of the collapse of the soft wall of the pharynx, which in turn leads to a partial or complete obstruction of the upper airways and thus a unique challenge for the anesthesiological approach during a surgical procedure for the treatment of pathological obesity ( 2 ). As a consequence of long-term unrecognized OSA, hypoventilation syndrome can occur, which is a state of gradual reduction of the sensitivity of the breathing center in the brain. The clinical picture is dominated by somnolence, dyspnea, and hypoxemia with the consequent polycythemia, cyanosis, and plethoric appearance ( 1 ). ## Influence on the heart and circulatory system Cardiovascular diseases are the dominant causes of mortality and morbidity in pathologically obese persons. The incidence rises significantly with a BMI >35kg/m 2 . Arterial hypertension is the most common disease associated with obesity. Mild and moderate hypertension can be found in over 60 % of patients with obesity, whereas a severe level of hypertension is present in 5-10 % of pathologically obese persons ( 1 ). Hypertension results from the interaction of genetic predispositions and hormonal, renal, and hemodynamic factors. Obese persons have increased risk of ischemic heart disease, heart arrhythmias, and the development of myocardiopathy. It is believed that one of the reasons for the development of arrhythmias is the infiltration of fat cells into the myocardium, which generally happens in the right ventricle and can lead to disorders in the circulatory system of the heart. ## Influence on the digestive system and liver function Although it is believed that the stomachs of obese persons empty faster, most likely due to the larger volume of the stomach itself, they almost always have gastric residual, increased pressure in the abdominal cavity, and increased risk of aspiration of gastric content during the induction of anesthesia ( 4 ). Additionally, positive pressure ventilation during anesthesia induction can lead to stomach bloating and regurgitation of stomach contents. In obese patients it is therefore recommended to apply prokinetic medication, H2-receptor blockers, or proton pump inhibitors before the induction of anesthesia to reduce the consequences of the aspiration of acidic gastric contents ( 5 ). More than 90 % of obese persons manifest histological changes due to fat infiltration in liver cells. Twenty percent of patients show signs of severe and diffuse hepatic steatosis, while 20–30 % of patients without clear liver changes present with elevated liver enzyme values. Among these, increased activity of alanine aminotransferase is the most common. Despite abnormal indicators of liver function, there is no clear association between routine liver function tests and liver capacity for drug/anesthetic metabolism ( 4 ). ## Influence on renal function Due to the increased blood flow through the kidneys in pathologically obese persons, the glomerular filtration rate and renal clearance of drugs are increased as well ( 6 ). The increase in glomerular filtration that can reach as much as 40 % in pathologically obese person’s cause’s glomerulopathy coupled with obesity, i.e. proteinuria, which is the most common renal function disorder in these patients, with stabilization of renal function occurring after surgical treatment ( 6 - 8 ). ## Preoperative evaluation and preparation of obese patients Preoperative evaluation of obese patients for a surgical procedure does not differ from that in patients with normal body weight, and depends on the overall health status, concomitant diseases, and the surgical procedure to be performed. In patients with concomitant diseases, the processing is expanded depending on the clinical status of the patient and includes examination by a cardiologists, ultrasound and cardiac stress tests, examination by a pulmonologist, arterial blood gas tests and spirometry, as well as comprehensive endocrinological examination. Patients with a diagnosis of OSA and hyperventilation syndrome who are being treated with continuous or biphasic positive pressure (CPAP masks) should be reminded to continue their treatment until admission to the hospital. The application of a CPAP mask should be continued as soon as possible in the postoperative course. Preoperative preparations also include mandatory application of low molecular weight heparin with mechanical thromboprophylaxis that includes the use of elastic compression due to the significantly increased risk of thromboembolic incidents in obese patients ( 2 , 4 ). Due to initially disordered lung function and reduced oxygen saturation in arterial blood, obese persons have an increased risk of complications during induction of anesthesia ( 5 ). As a consequence of excessive fat tissue accretion not only externally around the neck, chest cavity, and abdominal wall but also internally in the mouth and pharynx, establishing the airway and endotracheal intubation can be more difficult, especially in the supine position on the operating table. To prevent problems with intubation and airway management, it is important to properly adjust and position the obese patient on the operating table. Best visibility for endotracheal intubation is achieved by raising the upper part of the body by 25–30 % with the placement of a pillow under the head and neck, so as to line up the outer ear canal with the sternum (the so-called ramp position). This achieves the best visibility of the airways. Due to the rapid decrease in oxygen saturation of arterial blood, an oxygen mask should be applied in obese patients before induction of anesthesia. The combination of preoxygenation (administering oxygen through a mask before induction of anesthesia) and the elevated position of the upper body enable the physicians to maintain arterial blood saturation at 100 % within a few minutes in the greatest number of cases. Applying positive end-expiratory pressure (PEEP) of 10 cm H 2 0 during preoxygenation and induction of anesthesia prolong the time for intubation before decrease blood oxygen saturation occurs ( 5 - 7 ). ## Choice of anesthesia in obese persons Due to increased volume of distribution, extended elimination half-life, increased glomerular filtration rate, and fat infiltration of the liver, the biotransformation of many anesthetics is altered ( 2 ). Application of lipophilic anesthetics such as barbiturates, benzodiazepines, and some opioids is recommended at a higher dose because of increased volume of distribution ( 2 ). Propofol and remifentanil are the exception. Determining the dose of propofol should be adjusted to the age and ideal body weight of the patient, since dosing based on total body weight (TBW) can cause serious depression of the cardiocirculatory system. The volume of distribution for less lipophilic drugs such as muscle relaxants is not significantly altered, so these drugs can be dosed based on ideal body weight, or, more precisely, lean body mass. Succinyl cholinesterase activity is reduced in obese persons, and dosing should be based on total body weights. Opioids are extremely lipophilic, so the initial dose should be based on TBW, but the maintenance doses must be reduced due to the increased sensitivity of obese patients and the possible development of respiratory depression. Among volatile anesthetics for the maintenance of anesthesia, anesthetics with lower solubility in lipids should be used because they allow rapid achievement of the appropriate depth of anesthesia and faster awakening and recovery after the surgical procedure is complete. Potent volatile anesthetics such as sevoflurane, desflurane, and isoflurane are safe for the maintenance of anesthesia ( 4 ). During anesthesia, it is recommended to use controlled mechanical ventilation with a greater tidal volume of 15–20 mL/kg, breathing frequency of 12–14 /min, and the application of PEEP, with the goal of achieving better oxygenation and a lower incidence of atelectasis. Mandatory monitoring during the surgery includes an electrocardiogram, non-invasive pressure measurement, pulse oximeter monitoring, and capnography. In high risk patients, an arterial line is also introduced to continuously measure arterial pressure and determine blood gas, and a pulmonary catheter is used in patients with pulmonary hypertension. Regional anesthesia has also become increasingly popular in obese patients ( 2 ). Although significant technical difficulties can occur during anesthesia itself, regional anesthesia has certain advantages in comparison with general anesthesia, which include avoiding potential issues with establishing airflow, avoiding drugs that can cause cardiorespiratory depression, reducing postoperative nausea and vomiting, and better postoperative pain management ( 2 , 5 ). Monitoring during a surgical procedure for patients under regional anesthesia is the same as in patients under general anesthesia ( 4 , 5 ). Enhanced monitoring is also necessary during early postoperative course. This includes monitoring of SaO 2 and administering oxygen through a mask or nasal catheter, blood pressure and diuresis monitoring, and application of continuous positive airway pressure therapy (CPAP) in patients with OSA ( 2 ). Appropriate analgesia is also important since it prevents hypoventilation, secretion retention, and the development of pneumonia. The use of patient-controlled intravenous analgesia or thoracic epidural analgesia is recommended, depending on the type of surgical procedure ( 4 , 5 ). ## Surgical procedures in the treatment of pathological obesity Regarding issues associated with obese patients, it is important to note that surgical procedures are being performed today with the express goal of treating pathological obesity. Treating obesity requires a multidisciplinary approach that includes a wide range of dietary measures, changes in life habits, physical activity, and the use of various medications. Most of these measures, however, only result in a limited and temporary loss of body mass, which is one of the reasons for an increasing tendency towards resorting to surgical treatment or bariatric surgery. Bariatric procedures change the capacity and anatomy of the digestive system and are recommended as treatment for obesity in persons with a BMI above 40 kg/m 2 or persons with a BMI above 35 kg/m 2 with concomitant diseases such as arterial hypertension, diabetes, or cardiorespiratory disorders. There are a number of bariatric surgical procedures, two of which are most commonly performed ( 7 , 8 ). Adjustable gastric bands are placed around a part of the stomach immediately below the cardia, creating a small reservoir about 25 mL in volume that quickly fills up with food and sends an »earlier« message of satiation to the brain, helping the patient stop eating. This method primarily reduces the intake of food, thus making it a restrictive method of treatment. The amount of food intake restriction is controlled by a circular balloon within a ring that can be filled with or emptied of water or air through a port placed in the abdominal cavity. After this surgical procedure, the patient can achieve a reduction in excess body weight of approximately 50 ± 28 % over 2 years ( 8 ). ## Gastric bypass The Roux-en-Y gastric bypass is the most common surgical procedure in bariatric surgery today and is considered the “gold standard” in the treatment of pathological obesity. This procedure creates a small reservoir in the stomach, which achieves the restrictive component of the procedure (reduced food intake), and since the greater part of the stomach and the whole duodenum are bypassed, there is a malabsorptive component to the procedure as well. Food absorption is significantly reduced due to the exclusion of the duodenum and a part of the small intestine from digestion and because food is redirected to the small intestine from a small part of the stomach. This type of surgical procedure is considered to be the most effective method of treating pathological obesity, resulting in a loss of excess weight of 55-77 % while effecting the recovery of previously disordered renal function due to obesity ( 8 ). ## Conclusion Pathological obesity is a systemic illness that affects a growing number of people every year and is associated with damage to almost all systems in the body, including the respiratory, renal and cardiovascular, gastrointestinal, and endocrine systems. Most measures applied in the treatment of obesity result in only limited and temporary loss of body mass, which is one of the reasons why the use of surgical treatment or bariatric surgery is becoming more widespread today. Obesity represents a risk during surgical procedures, but proper positioning of the patient and preoxygenation reduce the likelihood of failed intubation and desaturation in the patient during induction of anesthesia, allowing a long-term solution to obesity with the primary goal of preserving the health of the heart and kidneys ( 3 , 7 ).