Surgical Risks: What's the Big Deal?

by Robert B Albee, MD

Pain Medications

Pain can make us feel imprisoned in our own bodies. At one time or another most of us have used narcotics (or other pain medication) to achieve relief from severe pain. My recent knee surgery reminded me of this in a very personal way. Unfortunately, some have found medication to be the only way they can get relief from chronic, severe pain. Thus they use it regularly. 

A person facing surgery who has taken opiates regularly for longer than two weeks may encounter added surgical risks. Although the following list is incomplete, it gives some examples of the impact long-term use of these drugs can have. 

• Anesthesiologists note a consistent need for larger doses of medications for anesthesia and analgesia. This means the patient may receive doses closer to critical levels that can have side effects and consequences. Because critical levels can vary from one person to another without any indicators, the increase in the required dose elevates the relative risk.
  
   
• Nurses in post-operative care report that larger doses of medication are needed to keep these patients comfortable. This can result in excessive drowsiness, disorientation, and misunderstanding.
  
   
• Post-operative constipation is a much more frequent problem as well as a slowed return to bowel function (ileus).
  
   
• It is much more difficult for doctors to monitor for signs of surgical complications because of reduced communicating abilities.
   

• It is much more difficult to evaluate the success of the surgery because pain evaluation can be complicated by a physiological and/or psychological, dependence on pain medication.

Smoking

 The regular inhalation of smoke has an enormous number of different unhappy consequences for the patient undergoing surgery. The good news is that studies show patients who quit smoking as little as two weeks before surgery show remarkable improvement in the tolerance of anesthesia. Other risks for smokers include:

• Chronic lung disease and emphysema increase anesthesia risks.

• Smokers increase the methemoglobin in their blood stream, which reduces the ability of the red blood cells to deliver oxygen to the cells in the body. All organs can suffer.
   
• Infection rates after surgery are significantly increased.

• As a group, smokers tend to have altered abilities to absorb nutrients from their stomach and small intestine. They are commonly malnourished and frequently take oral medications without receiving the expected benefits.

Obesity

In 1998, an expert panel convened by the National Institutes of Health (NIH) recommended that Body Mass Index (BMI) be used to classify overweight and obese people. BMI is a measure of weight in relation to height. The formula to calculate BMI is:

            BMI = weight (kg) / height (m)²

 Non-metric users may find this formula easier:

             BMI = weight in pounds / (height in inches x height in inches) x 703

For example, a person who is 5’4” tall and weighs 180 has a BMI of 30.9. The NIH panel tells us that a person is considered overweight with a BMI of 25 to 29.9, and obese at 30 and up. At a BMI of 35 or greater, the person is considered morbidly obese. Approximately 16 million Americans fit this category.

Surgical patients with a BMI of 35 or more face the following additional risks:

• Size can cause some mechanical problems with the logistics of surgery. The use of the laparoscope is affected by the thickness and mass of the anterior abdominal wall and the distance between the lowest rib and the top of the hips.
   
  • The laparoscope is about 13 inches long (330 mm). The abdominal wall is used as a fulcrum in the middle of the shaft of the scope to steady it and to provide a stabilizing point for the trocar through which the scope is inserted. The thicker the abdominal wall is, the more scope movement is restricted and the more force it takes to move it.
    
    This example might help. Putting a plastic straw through a single lid of a fast food soft drink is easy. You can move the straw in any direction. But if you stack two lids, it becomes more difficult to get the straw in, and it won’t move as freely or as far. Now try six or eight lids together. It’s hard to get the straw in, and harder still to maneuver it.
    
    In an extremely heavy patient, the limitation of movement becomes an insurmountable problem. Areas of the abdomen and pelvis that should be easily seen can become inaccessible. Surgeon fatigue from forced muscular exertion to overcome resistance can increase exponentially as the length of the procedure increases.

• The overall contents of the abdomen and pelvis are basically the same for all of us. If the amount of space available for these contents is reduced by short stature, there may be significantly less space available to our instruments. When visualization is greatly reduced, the surgeon’s operating risk is greater.
  
   
• Using carbon dioxide gas to inflate the abdomen and pelvis for surgery is generally safe to about 15 mm Hg pressure. With an obese individual, more pressure is sometimes needed to create the operating space. If pressures above 15 mm Hg are used, there is a greater risk of increasing levels of carbon dioxide in the blood, greater risk of carbon dioxide embolization, and greater risk of subcutaneous emphysema (carbon dioxide leaking out into the tissues of the body, under the skin).

• The thicker the abdominal wall is, the harder it is to see the blood vessels that go through it. Therefore risk of injury to these vessels is increased.
  
   
• The longer the procedure lasts, the greater the risk of complications relating to pressure on the dependent parts of the body. Reported injuries include
   
  • Blood clots in the extremities
  • Nerve palsies and paralysis
  • Peripheral edema
    
     
• Obese patients have extra lipid deposits in virtually every area of their bodies. In the pelvis we notice this particularly in the mesentery of the bowel. Blood supply to this tissue is extremely fragile. Because we must handle this tissue to move it out of the operative field, we tend to have more bleeding occur. When visualization is already limited by factors such as those described above, we can have problems finding and controlling the bleeders.

Diabetes

Diabetes is a common illness that can significantly raise the relative risks of surgery. Insulin dependent diabetics at the CEC are treated in concert with endocrinologists. 

• Surgery intrudes into the routine of diet and insulin use. Diabetes is best controlled when the blood sugar remains in a narrow range. Blood sugar must be monitored carefully to avoid extremes and insulin doses must be varied according to changes in diet, activity, IV fluids, and insulin dosage.

• Diabetics require close observation because they are more at risk for infection.

Immune Problems

Ideally, we would not choose any elective surgery in a patient with any significant form of immunologic deficiency. This includes patients on chemotherapy, steroids, and patients with AIDS.

Medications 

Many commonly used medications (including over-the-counter drugs and herbs) can alter the surgical risks for a given patient. It is very important that you disclose any and all drugs you may be taking, whether they are legal or not.

Summary

We have listed many factors to be considered when planning a surgical procedure. Having one or more of these risk factors does not mean you will not be accepted as a patient at the CEC. However, it is important that you become aware of how your personal situation can impact the safety and efficiency of any procedure.

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