الفهرس 
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Abstract
Obesity is considered a major health and socio-economic problem. Overweight, obesity and morbid obesity are terms often used to describe individuals with an increased body fat. The most common definition of morbid obesity is a body mass index (BMI) of 40 Kg /m2 or more. The etiology of this condition is multifactorial including; familial and genetic predisposition, drug induced obesity, endocrinal causes, childhood overnutrition, intake of food in large quantities and many times in the day, psychological factors, environmental factors, special habits like alcohol consumption and smoking and personal factors like; age, gender, ethinity and parity.
Clear understanding of the pathophysiology of morbid obesity is essential for management and prevention of this disaster. There are several factors concerning the occurrence of obesity, the first one is the genetic control also central nervous system control , afferent signals, pattern of feeding, socio-economic factors, exercise and pattern of distribution of excess adipose tissue.
There are many disastrous diseases associated with morbid obesity including; cardiovascular diseases, diabetes mellitus, respiratory problems, digestive diseases, arthritis, chronic abdominal compartmental syndrome, hernia, infectious problems, endocrinal abnormalities, psychological problems, complications associated with pregnancy, cancer, neurological complications and other medical problems compounded by obesity.
Approximately 5% of morbidly obese patients may have obstructive sleep apnea syndrome. Recurrent attacks of apnea during sleep leading to hypoxemia, hypercapnia and pulmonary and systemic vasoconstriction. Recurrent hypoxemia leads to secondary polycyathemia and is associated with an increased risk of ischemic heart disease, while hypoxic pulmonary vasoconstriction leads to right ventricular failure.
Morbid obesity is associated with reductions in functional residual capacity, expiratory reserve volume and total lung capacity. These changes have been attributed to mass loading and splitting of the diaphragm.
Cardiovascular system dominates morbidity and mortality in obesity and manifests itself in the form of ischemic heart disease, hypertension and cardiac failure. Hypoxia, hypercapnia, electrolyte disturbance caused by diuretic therapy and coronary heart disease may precipitate arrhythmias in obese patients.
Diagnosis of morbid obesity can be done by several ways including clinical examination, calculation of body mass index (BMI>40 Kg/m2), measuring skin folds, also imaging techniques can be applied to measure the distribution of body fat as magnetic resonance techniques and dual energy X-ray absorptiometry.
Treatment of morbid obesity may be conservative as medical treatment (behavior modification, diet regimen, exercise and drugs) and active physical interventions ( gastric balloon, acupuncture and waist cord) or it may be surgical as which may be open as gastric bypass , intestinal bypass and gastroplasty which divided in to vertical banded gastroplasty, horizontal gasroplasty, gastric banding and gastric wrap or laparoscopic surgery as laparoscopic vertical banded gastroplasty, laparoscopic adjustable gastric banding, laparoscopic gastric bypass, laparoscopic malabsorpative procedure and laparoscopic bariatric pacing.
Surgical treatment seems to be more effective in the management of morbid obesity with acceptable rate of complications. The surgical modalities used in the bariatric surgery initially used in treating other conditions and these modalities were found to cause weight loss postoperatively as a side effect.
Complications of bariatric surgery include; abdominal catastrophe, wound infections, anastmotic leakage and stenosis, splenic capsule tear, gastric stasis, bleeding, pulmonary complications, cholelithiasis and neuropathy.
Morbid obesity changes the management of anesthesia at every possible step and in all possible ways starting from getting a venous access to maintaining adequacy of post-extubation ventilation.
Great care should be taken in the preoperative assessment. Careful history, clinical examination and investigations should be played more towards cardiovascular diseases, pulmonary functions as well as endocrinal abnormalities including thyroid function and diabetes mellitus.
Anesthetic management of obese patients should take into consideration the specific problems associated with obesity and optimize them before surgery. Antibiotics, anxiolysis, analgesia and prophylaxis against both aspiration pneumonitis and deep venous thrombosis should be addressed during premedication.
Intra-operative considerations include proper positioning of obese patients. Particular care should be paid to protection of pressure areas because pressure sores and neural injuries are more common in this group.
Proper monitoring of these high risk patients with full routine monitors, especially capnometry and pulse oximetry should be done. The electrocardiogram demonstrates the cardiac rhythm status continuously. Invasive arterial blood pressure monitoring and central venous catheterization can be used for morbidly obese patients with severe cardiopulmonary disease.
Anesthesia for bariatric patients has been established with a broad usage of agents and techniques. General anesthesia using balanced anesthesia technique including intravenous induction agents like: thiopentone, propofol, etomidate and inhalational agents like: nitrous oxide, isoflurane, desflurane and sevoflurane has been reported. Variety of muscle relaxants including succinycholine, mivacurium, atracurium, vecuronium and rocuronium can be used aiming at rapid recovery and cardiovascular stability.
Epidural anesthesia was considered as a safe alternative to general anesthesia for outpatient surgery without associated respiratory depression. A combination of balanced anesthesia using muscle relaxant, intravenous and epidural narcotics and artificial ventilation combat the effect of surgical insult and the effects of pneumo-peritonium, namely the resorption of carbon dioxide, diaphragmatic movement impairment and the reduction in lung volumes.
The most important complications that may face the obese patients postoperatively include respiratory problems, deep venous thrombosis, wound infection, rhabdomyolysis and complications of bariatric surgery. Even mortality may occur.
Oxygen supplementation is essential postoperatively. Adequate pain relief and measure to avoid deep venous thrombosis and pulmonary embolism should be taken including early ambulation. Postoperative admission to intensive care unit may be required for careful monitoring of cardiovascular functions, respiratory functions, drug dosing and vascular access, administration of oxygen therapy and narcotics.
Bariatric surgery is a safe variable option in the management of obese patients when non surgical treatment options have been unsuccessful. It requires expert group of surgeons, anesthesiologists, medical stuff and well prepared centers for such cases.