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Laparoscopic surgery in the obese: Safe techniques

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Increases in atelectasis, wound infection, and other risks after laparotomy point to laparoscopy as the safer route.


 

References

Gynecologic laparoscopy in the obese? What was once the purview of the very talented or the foolhardy may now be the preferred surgical approach.

Obese women who undergo laparoscopy recover faster, with less pain, fewer wound infections, and shorter hospital stays than with laparotomy. Though it is true that obesity increases operative time and the risk for conversion to laparotomy, little evidence supports the theory that a body mass index (BMI) of 30 kg/m2 or higher should exclude laparoscopy.

Preoperative management

Unique elements of the physical

It is important to identify central obesity, which is more difficult to accommodate than distribution around the hips. Unfortunately, the roughly 40 million obese Americans tend to have central fat distribution.1,2

In central obesity, the subcutaneous tissue is thick, often requiring extra long ports to attain peritoneal access.

The relationship of the umbilicus to the underlying aortic bifurcation also shifts more caudally. This relationship should be noted and planned for before going to the operating room (FIGURE).

Abdominal obesity in particular confers additional risks during all types of surgery: higher rates of atelectasis, thromboembolism, cardiovascular dysfunction, and wound infection.

Closely inspect the skin and panniculus after a routine examination. Obesity predisposes patients to dark, moist, anoxic spaces beneath folds of skin that need to be identified and inspected for evidence of fungal or bacterial infection. To optimize postoperative wound healing, treat any preexisting infections before surgery.

Cigarette smoking further burdens pulmonary mechanics and oxygenation during surgery, so it is important to encourage smokers to kick the habit at least 8 weeks before elective surgery.3

In general, use the history and physical examination to focus on the recognized risk factors of obesity, with specific emphasis on hypertension, coronary artery disease, arrhythmia, pulmonary obstructive disease, peripheral vascular disease, diabetes, gastric reflux, and arthritis.4

Special tests and laboratory studies

EKG and chest x-ray. In morbidly obese patients (BMI >40), preoperative evaluation includes an electrocardiogram (EKG) and chest x-ray to identify any cardiomegaly, arrhythmias, and occult ischemia or conduction blockage.

Arterial blood gas sampling. Given the higher risk of postoperative thrombotic events in obese patients, it can be helpful to assess preoperative oxygenation and ventilation/perfusion status via arterial blood gas sampling. The obese may have elevated baseline Aa gradients, which, if not noted prior to surgery, can confuse later management of suspected pulmonary emboli.

During testing, assess venous access and counsel the patient if central venous line placement may be possible at surgery. Though central line placement is not routinely recommended, it may be warranted in patients with particularly difficult peripheral venous access.

Skip pulmonary function testing because the results rarely change surgical management. We consider its routine use to be wasteful.

Laboratory evaluation should include betahuman chorionic gonadotropin (in premenopausal patients), complete blood count, electrolytes, glucose, renal function, and type and screen.

Spell out risks at informed consent

The preoperative appointment is your chance to answer questions the patient may have and clearly delineate the risks and benefits of surgery. During this discussion, spell out the increased risks of conversion to laparotomy, prolonged anesthesia, postoperative thrombosis, wound infection, and pulmonary complications, and make sure all are listed on the written consent form.

Operative management

Prophylactic measures

Complete bowel preparation is recommended the evening prior to surgery, since intraabdominal visualization can be difficult and conversion to laparotomy may be necessary. Bowel prep decompresses the lumen, improving visualization and the outcome of any bowel injury.

Preoperative histamine receptor blockade is recommended for optimal results, since higher body mass can lead to increases in low pH gastric volume and difficulties with intubation.5 A typical regimen is 50 mg intravenous (IV) ranitidine 20 minutes prior to surgery.

Beta blockade. All patients with hypertension or a history of coronary artery disease should receive preoperative beta blockade, assuming there are no contraindications such as reactive airway disease or cardiac conduction block. Atenolol 10 mg IV 20 minutes prior to surgery is a standard initial dose. All patients already taking beta blockers should simply continue their home regimen through the day of surgery with small sips of water.

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