For any given surgical procedure there are two types of complications. One type is specific to the particular procedure being performed. For example, temporary incontinence is a possible complication for bladder surgery, but not for heart surgery.
The second type of complication is one which is a potential risk for most or all types of surgery. These types of complications include an adverse reaction to anesthetic, or a risk of post-surgery infection.
Some complications, such as respiratory issues, reactions to anesthetic, and hemorrhage, can occur during surgery. Others develop after the surgery has been completed, when the patient is recovering. Most post-surgery complications appear within one to three days after the procedure. Some of the most common complications that can occur after surgery include fever or infection, poor wound healing, and blood clots.
Reaction to Anesthesia
Adverse reactions to anesthetic medication are rare, but can occur. Symptoms include a rash, wheezing, dizziness, fever, low blood pressure, confusion, agitation, and liver problems. Most adverse reactions are mild and temporary.
The risk of an adverse reaction is difficult to minimize, because unless there is a family history of adverse reactions, it is generally impossible to predict.
Respiratory problems are one of the most common complications of surgery that can occur during the procedure itself. This complication can occur in up to fifteen percent of people who undergo major surgery that includes a general anesthetic.
Lung congestion and pneumonia are risks following almost any type of surgery. To combat this risk, patients are generally advised to ensure they breathe deeply during recovery. Often, a patient is given deep-breathing exercises to do several times a day while he or she is recovering from a procedure.
This complication can occur during or shortly after surgery. Certain types of surgery carry a higher risk of hemorrhage than others. For example, surgery that involves the removal of a vascularized organ carries a higher risk of hemorrhage. When a hemorrhage occurs after surgery, it is often due to a sudden rise in blood pressure, or to blood vessel damage caused by post-operative infection.
The risk of hemorrhage can be reduced by avoiding blood thinning medications before the surgery. People who take blood thinners will be told, prior to their surgery, when they should stop taking the medication.
Infection or Poor Wound Healing
Infection and delayed wound healing can develop if bacteria invade the surgical wound. Infection can be treated with wound management and antibiotics. Sometimes, wounds heal slowly in the absence of infection. This is sometimes partly due to reduced circulation, as a result of reduced physical activity after surgery. Gentle exercise can help with wound healing, because exercise helps improve the circulation.
These are more common complications of surgery for people who are malnourished, are in poor general health, or who have a circulatory disease such as diabetes.
Deep vein thrombosis and other types of blood clot complications can be potentially fatal, making it very important that these are prevented or diagnosed early.
One of the risk factors for blood clots is reduced mobility after surgery, as this also reduces circulation. The risk can be reduced with regular gentle exercise, blood thinning medication (as long as there is no risk of hemorrhage), support stockings to improve circulation, and elevation of the legs and feet.
Merck Manual of Health and Aging: Some Potential Complications of Surgery
PatientUK: Common Post-Operative Complications
St. Lucie Medical Center: Risks or Potential Complications of Surgery
University of Virginia: Discomforts and Complications After Surgery