Each year, more than 30 million surgical procedures are performed. During these, nearly 1 million patients suffer a postoperative complication (Mangano, 2004). As surgeons, gynecologists assume responsibility for assessing a patient's clinical status to identify modifiable risk factors and prevent perioperative morbidity. However, clinicians should also be prepared to diagnose and manage such complications, if they arise.
A properly performed preoperative evaluation serves two important functions. It uncovers comorbidities that require further evaluation and optimization to avert perioperative complications (Johnson, 2008). Second, evaluation allows improved use of operating room resources (Correll, 2009; Roizen, 2000).
In many cases, a gynecologist can perform a thorough preoperative history and physical examination, averting the need for medical consultation in many cases. However, if a poorly controlled or previously undiagnosed disease is discovered, consultation with an internist can be beneficial. The purpose of a preoperative internal medicine consultation is not to obtain “medical clearance” but rather to provide a risk assessment of a woman's current medical state. With consultation, a summary of the surgical illness is provided, and clear questions are posed to the consultant (Eagle, 2002; Fleisher, 2009; Goldman, 1983). In addition, a complete history and physical examination and medical records that report prior diagnostic testing should be available to the consulting physician. This can prevent unnecessary surgical delays and cost due to redundant testing.
Common postoperative pulmonary morbidities include atelectasis, pneumonia, and exacerbation of chronic lung diseases. Incidences of such complications following surgery are estimated between 20 and 70 percent (Bernstein, 2008; Brooks-Brunn, 1997; Qaseem, 2006).
Risk Factors for Pulmonary Complications
Risk factors for pulmonary complications fall into one of two major categories—procedure- related and patient-related. For example, upper abdominal incisions as they approach the diaphragm can alter pulmonary function through three mechanisms, as shown in Figure 39-1. First, intraoperative stimulation of the viscera leads to decreased phrenic motoneuron output, which then lessens diaphragmatic descent. Second, disruption of abdominal wall muscles can hinder effective respiratory efforts. Finally, pain may limit effective voluntary use of respiratory muscles. As a result, poor diaphragmatic function may produce persistent decreases in vital capacity and in functional residual capacity. These predispose patients to atelectasis (Warner, 2000). Surgery duration is another procedure-associated factor. Procedures in which patients receive general anesthesia for longer than 3 hours are associated with nearly double the risk of developing a postoperative pulmonary complication. Finally, emergency surgery remains a significant independent predictor of postoperative pulmonary complications. Although these procedure-related risk factors are largely unmodifiable, an appreciation of their associated sequelae should prompt increased postoperative vigilance.
Surgical factors producing respiratory muscle dysfunction. These factors ...