20.1

Introduction

Obesity is associated with various conditions, including diabetes mellitus, hypertension, hypercholesterolemia, heart disease, asthma, and arthritis. All these conditions contribute to increased morbidity and mortality in gynaecology surgery. Obese women with metabolic syndrome (specifically hypertension and diabetes) who underwent general, vascular, and orthopaedic surgery are at increased risk of perioperative morbidity and mortality compared with normal-weight patients.

Based on the data, the American College of Obstetricians and Gynecologists made the following recommendations in a recent committee opinion paper:

• 1.
  

  Gynaecological surgeons should have the knowledge to counsel obese women on the risks specific to this group.

  
  
• 2.
  

  As with all patients, evidence demonstrates that, in general, vaginal hysterectomy is associated with better outcomes and fewer complications than laparoscopic or abdominal hysterectomy.

  
  
• 3.
  

  Wound complications, surgical site infections, and venous thromboembolism are the main cause of morbidity in obese women who underwent gynaecology surgery.

  
  
• 4.
  

  Every effort should be made to offer all patients, regardless of BMI, the least invasive procedure in order to decrease complications, length of hospital stay, and postoperative recovery time.

20.2

Decision-making about surgery

• 1.
  

  Ensure that surgery is appropriate and there are no other alternative nonsurgical management options to deal with immediate issues until weight management has been addressed.

  
  
• 2.
  

  Consider conservative therapies, such as the Levonorgestrel-releasing intrauterine system for menstrual dysfunction, bladder retraining and physiotherapy for urinary problems, and pessaries for prolapse, should be considered as an option.

  
  
• 3.
  

  Obese women and their families should receive careful counselling about the increased risk of complications during surgery, possible technical challenges which may be encountered during surgery, and specific issues related to postoperative recovery

  
  
• 4.
  

  It is the clinician’s duty to help them understand the problem from a medical point of view, and how risks related to surgery can be reduced. There is a case to offer bariatric surgery for morbidly obese woman, if conservative treatment had failed, and she has other significant comorbidities.

20.3

Physiological changes in obese women

• 1.
  

  Central (visceral) obesity leads to several cardiovascular and haemodynamic changes associated with physiological abnormalities. A Scottish survey reported that the prevalence of cardiovascular disease was 37% in adults with a BMI >30 compared to only 10% in adults with a BMI of <25.

  
  
• 2.
  

  Hypertension is common in obese patients with 60% of obese patients having mild–moderate hypertension and 5%–10% having severe hypertension.

  
  
• 3.
  

  Cardiac arrhythmias are more common in obese patients and may be caused by a number of factors, including hypoxia, electrolyte imbalance, myocardial hypertrophy, and myocardial infiltration of the conducting system.

  
  
• 4.
  

  Autopsy studies have shown that there is an association between obesity and cardiomyopathy with a 20%–55% increase in cardiac diameter, ventricle size, and cardiac weight for the obese patients compared to the nonobese patient.

  
  
• 5.
  

  Class III obesity is associated with a decrease in functional residual capacity, shallow breathing pattern, an increase in peak inspiratory pressure, decreased expiratory reserve volume, and total lung capacity.

  
  
• 6.
  

  The functional residual capacity (FRC) is reduced in the obese patients when lying in supine position with an impaired tolerance for the Trendelenburg position for the laparoscopic surgery.

  
  
• 7.
  

  Steep Trendelenburg position along with CO ₂ Pneumoperitoneum results in a greater arterial partial pressure of CO ₂ (paCO ₂ ) during Laparoscopic and robotic surgery. The end-tidal CO ₂ remains constant and therefore leads to an elevated PaCO ₂ -EtCO ₂ gradient (hypercapnia), which in turn reflects increased dead space, “Obesity hypoventilation syndrome.” The FRC is further compromised by anaesthesia to levels lower than closing capacity resulting in airway closure and hypoxemia.

  
  
• 8.
  

  Obesity is a well-established risk factor for developing obstructive sleep apnoea; the higher the BMI, the higher the risk.

  
  
• 9.
  

  As the FRC and expiratory reserve volume drops, the mismatch in ventilation perfusion promotes alveolar collapse and atelactasis at the lung bases. The decrease in chest wall compliance can be as high as 60% after pneumoperitoneum is created.

  
  
• 10.
  

  Morbidly (Class III) obese patients are at a higher risk of developing hypercapnia and acidosis which can cause cardiac arrhythmias and vasoconstriction of pulmonary vessels, depressive effect on cardiac myocardial contractility, and tachycardia.

  
  
• 11.
  

  Obese patients are at increased risk of gastric acid aspiration, especially during minimal access/or invasive abdominopelvic surgery, because of increased intragastric pressure, large gastric volume, altered secretion of adipokines, predisposition to reflux, lower gastric pH, and delayed gastric emptying.

  
  
• 12.
  

  Increased intraabdominal pressure during minimally invasive surgery can reduce the peak femoral systolic velocity and increase the femoral vein cross-sectional area. Sequential compression devices should be used to reverse this effect along with the use of prophylactic antithrombotic agents to prevent deep venous thrombosis.

20.4

Preoperative evaluation

• 1.
  

  Preoperative detailed assessment by the anaesthetic team should be considered.

  
  
• 2.
  

  The anaesthetist will consider whether tracheal intubation and airway management will be difficult due to adipose tissue in the neck and limited neck/cervical spine movement.

  
  
• 3.
  

  Obese patients with metabolic syndrome undergoing noncardiac surgery are at increased risk of cardiovascular complications. A 12-lead cardiogram is recommended at preoperative evaluation and other tests, such as echocardiogram, based on the class of obesity and findings of physical examination, should also be considered.

  
  
• 4.
  

  In patients with diabetes mellitus, blood glucose evaluation and counselling the woman on the importance of euglycemia to improve postoperative wound healing are important.

  
  
• 5.
  

  Specialist investigations are required if obstructive sleep apnoea is suspected from a history of daytime somnolence, morning headaches, nocturnal wakening, and partner reports of loud snoring and apnoeic episodes during sleep.

  
  
• 6.
  

  Thorough abdominal and pelvic assessment should be carried out to decide upon the best route for surgery with the help of ultrasound scanning and magnetic resonance imaging to determine the best route of surgery. Even an examination under anaesthesia may provide more guidance.

20.5

Equipment and general considerations

• 1.
  

  Careful surgical planning is required in terms of personnel and availability of equipment.

  
  
• 2.
  

  There should be clear and early communication among members of the multidisciplinary team involved in the care of obese patients to agree on the plan of management and the availability of resources (appropriate equipment).

  
  
• 3.
  

  Risk to the patients in receiving suboptimal care due to lack of appropriate equipment can be a potential medico-legal issue.

  
  
• 4.
  

  Risk assessment and training for staff is required for appropriate manual patient handling, to protect themselves and patient.

  
  
• 5.
  

  Bariatric operating table that can handle 300 kg with appropriate extension is needed together with “Obesity Packs” as recommended by the Royal College of Anaesthetists (United Kingdom).

  
  
• 6.
  

  Obese patients are at risk of slipping off the table during position changes and therefore they must be secured to the table. All pressure points should be well padded, as there is a risk of nerve injury and of rhabdomyolysis of the gluteal muscles leading to renal failure among class 111 obese.

  
  
• 7.
  

  Special hospital beds should be available that can accommodate the weight and enable movement of the patient without manual handling.

20.6

Anaesthetic challenges

• 1.
  

  As a good practice, two experienced anaesthetists may pair up to support each other during complex procedures for class 11–111 obese.

  
  
• 2.
  

  During anaesthesia, obese patients in supine position require a 15% higher minute ventilation to maintain normocarbia.

  
  
• 3.
  

  In Trendelenburg position, the steeper the head-down position, and higher the pneumoperitoneum pressures, the greater the problem becomes, requiring higher minute ventilation.

  
  
• 4.
  

  An imbalance between perfusion and ventilation within the lung tissue results is increasing difficulty for the anaesthetist to maintain oxygenation for these patients especially in prolonged and complex surgery.

20.7

Thromboprophylaxis

• 1.
  

  The risk of perioperative deep vein thrombosis and pulmonary embolism is higher among obese people than among those of normal weight and it occurs in 5%–12% of obese patients who undergo surgery.

  
  
• 2.
  

  Obese people are at increased risk of venous stasis pre- and postoperatively.

  
  
• 3.
  

  Obesity is associated with increased levels of fibrinogen and factor VIII. Therefore, if they are on any oestrogen-containing treatment, then it should be discontinued at least 4 weeks before surgery.

  
  
• 4.
  

  Appropriately sized thromboembolic stockings should be used along with mechanical devices such as intermittent pneumatic compressions during surgery and also during the postoperative period, especially for class III obese until mobile.

  
  
• 5.
  

  There should be a departmental evidence-based protocol about the use of low-molecular-weight heparin (LMWH), starting a minimum of 2 hours postoperatively, unless there is a contraindication (it should be recorded in the case notes).

  
  
• 6.
  

  Treatment with LMWH should be extended to 4 weeks in cases of pelvic surgery for malignancy.

20.8

Sepsis prophylaxis

• 1.
  

  Obesity has been shown to impair immune response leading to impaired chemotaxis and macrophage differentiation.

  
  
• 2.
  

  Studies have also shown that obesity is associated with an increase in the risk of urinary tract infection, and pyelonephritis has been reported to be almost five times more common in obese female patients compared to nonobese.

  
  
• 3.
  

  Several studies have also reported an increased risk of skin and soft tissue infection in obese women.

  
  
• 4.
  

  For that reason broad spectrum antibiotics prophylaxis should be administered to patients especially to those with class II–III obesity.

20.9

Intraoperative challenges

20.10

Open abdominal surgery

• 1.
  

  Abdominal surgery is challenging and should be the last resort if other routes prove impossible.

  
  
• 2.
  

  Access and adequate exposure is difficult due to amount of subcutaneous adipose tissue.

  
  
• 3.
  

  There are higher incidences of intraoperative complications due to limited access and/or distorted anatomy.

  
  
• 4.
  

  To overcome this, it is vital to have good assistance, appropriate instruments, retraction and lighting.

  
  
• 5.
  

  Obese women are at increased risk of wound infection; therefore perioperative administration of adequate amount of antibiotics is vital for reduction in wound infection rates.

  
  
• 6.
  

  Lowest infection is observed in patients with antibiotics administration before incision is made

  
  
• 7.
  

  A higher dose or weight-dependent dose of antibiotics should be considered as a standard antibiotics prophylactic regime failed to achieve adequate tissue concentration in obese women.

  
  
• 8.
  

  Meticulous operating technique with minimal tissue handling and good haemostasis is vital to prevent postoperative complications.

20.11

Postoperative issues

• 1.
  

  Class II–III obese individuals should be admitted to a high dependency unit for postoperative care.

  
  
• 2.
  

  All patients should be fitted with thromboembolic-deterrent stockings, and advised on rehydration and early mobilisation.

  
  
• 3.
  

  Adequate dose of LMWH should be administered based upon weight of the individual and the risk factors, and most patients may require extended duration of venous thromboembolic prophylaxis.

  
  
• 4.
  

  Adequate analgesia is crucial to allow early mobilisation.

  
  
• 5.
  

  Respiratory morbidity (postoperative hypoxemia) is more common in obese patients, due to reduced FRC and atelactasis. It can be improved with supplemental oxygen, semirecumbent positioning and chest physiotherapy.

20.12

Conclusion

• 1.
  

  Obese patients commonly have comorbid conditions that can complicate intraoperative care.

  
  
• 2.
  

  A thorough assessment of the risk benefit should be discussed with women.

  
  
• 3.
  

  Appropriate planning of infrastructure upgrading to allow safe management of morbidly obese patients in an appropriate, safe, and adequately equipped environment is vital in the current upward trend of obesity in the world.