Does Risk Stratification Increase Or Decrease Patient Safety?
According to Michael Wong of the Physician-Patient Alliance for Health & Safety, the topic of who is a suitable candidate for outpatient surgery is front and center with productivity pressures being intense at ambulatory surgery centers. However, with surgery often comes the necessity of the use of opioids for pain control.
As Mr. Wong explains, "Studies have shown that any patient receiving opioids may be at risk of postoperative respiratory depression and if undetected, respiratory arrest (also known as "Code Blue"). The most common antecedents to cardiopulmonary arrest are of respiratory origin. Respiratory decompensation—as evidenced by tachypnea, bradypnea, hypoxia, hypercarbia or changes in mental status—are often the earliest warning signs of physiologic instability. Monitoring respiratory function and level of consciousness are especially important in detecting and preventing adverse events for patients receiving opioids and sedatives."
According to the report Ambulatory Surgery in the United States, 2006, the number of outpatient surgeries in the United States increased from 20.8 million in 1996 to 34.7 million in 2006. While outpatient surgeries only accounted for about half of all surgeries in 1996, by 2006 they made up nearly two-thirds of all surgeries in 2006. As Frank Overdyk, MD (Professor of Anesthesiology, Medical University of South Carolina) says, "There is often a sentiment that "it's only minor surgery". While a surgery may indeed be "minor" or less intensive and complicated, and non opioid analgesics are preferred in these cases, opioids are still frequently required for adequate postoperative pain control."
The Anesthesia Patient Safety Foundation convened a symposium in 2006 on the dangers of postoperative opioids, and the consensus opinion was that opioid-induced respiratory depression (OIRD) remains a significant and preventable threat to patient safety for which institutions must have zero tolerance. Moreover, in 2011, APSF reiterated that clinically significant drug-induced respiratory depression (oxygenation and/or ventilation) in the postoperative period remains a serious patient safety risk that continues to be associated with significant morbidity and mortality.
Unrecognized postoperative respiratory failure that results in cardiopulmonary arrest (CPA) is a daily occurrence at healthcare facilities across the United States. Since CPA results in death or anoxic brain injury in the majority of cases, these events have been termed "Failure to Rescue (FTR)". FTR is the first and third most common patient safety-related adverse events affecting the Medicare population in U.S. hospitals, accounting for 113 events per 1,000 at-risk patient admissions. Moreover, fifty percent of Code Blue events involve patients receiving opioid analgesia.
Postoperative patients usually receive opioid analgesia by patient-controlled analgesia (PCA). PCA has become part of accepted medical practice and is generally considered more effective and safer than conventional IM (Intramuscular) injection of opioids.
However, as Dr. Overdyk explains, "conventional PCA monitoring by nurses at the bedside fail to detect frequent episodes of slow breathing (bradypnea) and desaturation that continuous electronic monitoring have revealed."
The current standard of care for postoperative monitoring typically require vital signs and less commonly a SpO2 value, initially at 30-min intervals, but thereafter at intervals as far as 2–4 h apart. As recent APSF recommendations and conclusions state: Intermittent 'spot checks' of oxygenation (pulse oximetry) and ventilation (nursing assessment) are not adequate for reliably recognizing clinically significant evolving drug-induced respiratory depression in the postoperative period.
As Dr. Overdyk concludes, "Patient surveillance systems that use continuous monitoring with oximetry and capnography would facilitate early recognition of patient deterioration."
 Fecho K, Jackson F, Smith F, Overdyk F: In-hospital resuscitation: Opioids and other factors influencing survival. Ther Clin Risk Manag 2009; 5:961–8
 Overdyk FJ, et. al., "Continuous Oximetry/Capnometry Monitoring Reveals Frequent Desaturation and Bradypnea During" Patient-Controlled AnalgesiaAnesth Analg 2007;105:412–8