EXTUBATION IS RISKY BUSINESS. WHY THE CONCLUSION OF GENERAL ANESTHESIA CAN BE A CRITICAL EVENT

the anesthesia consultant

Physician anesthesiologist at Stanford at Associated Anesthesiologists Medical Group
Richard Novak, MD is a Stanford physician board-certified in anesthesiology and internal medicine.Dr. Novak is an Adjunct Clinical Professor in the Department of Anesthesiology, Perioperative and Pain Medicine at Stanford University, the Medical Director at Waverley Surgery Center in Palo Alto, California, and a member of the Associated Anesthesiologists Medical Group in Palo Alto, California.
email rjnov@yahoo.com
phone 650-465-5997
preparing to remove an endotracheal tube from a patient

Every general anesthetic has risk. In the immortal words of Forrest Gump, “Sh*t happens.” The conclusion of most general anesthetics requires the removal of a breathing tube. The removal of this airway tube, an event called “extubation,” is a critical and sometimes dangerous event. Extubation is risky business.

The most invasive type of airway tube used in anesthesia is called an endotracheal tube, or ET tube. At the onset of general anesthesia anesthesiologists place an ET tube through the mouth, past the larynx (voice box), and into the trachea (windpipe). The ET tube is a conduit to safely transfer oxygen and anesthesia gases into and out of the lungs.

After a surgery is finished, anesthetic gases and intravenous anesthesia drugs are discontinued, and the patient wakes up within 5 to 15 minutes. If the patient has an ET tube, it is usually removed. Anesthesiologists are vigilant during extubation. In contrast, other operating room professionals are usually relaxed and winding down at this time, because the surgical procedure is finished. Extubation is not a time to relax. The incidence of respiratory complications (e.g. low oxygen saturations or airway obstruction) occurred at a significantly higher rate following extubation than during induction of anesthesia (P < 0.01).

The Difficult Airway Society Guidelines for the Management of Tracheal Extubation state that “tracheal extubation is a high-risk phase of anesthesia. The majority of problems that occur during extubation and emergence are of a minor nature, but a small and significant number may result in injury or death.”

Let’s examine five actual post-extubation scenarios that caused death, complications, or a near-miss: 

  1. During my first month of anesthesia training at a county hospital in San Jose, California, I chose to try to wake up a healthy patient without the presence of my faculty member. When I removed the endotracheal tube, the patient was unable to breathe and his oxygen level dropped acutely. I didn’t know what to do, and in a panic I paged my faculty member. He entered the operating room, elbowed me aside, assessed the diagnosis of laryngospasm, applied an anesthesia mask over the patient’s face, and began a chin-lift maneuver while forcing positive pressure oxygen into the patient via the mask. Within ten seconds the patient coughed, began breathing, and the oxygen level rose to safe levels. I was aghast with the acute deterioration I had neither predicted nor known how to remedy. The faculty member looked me in the eye and said, “Don’t take out the endotracheal tube until the patient opens his eyes.” I took that endotracheal tube out too early because I was inexperienced—still years away from finishing my anesthesia training. Laryngospasm occurs when the vocal cords clamp together following removal of the ET tube. This is usually caused by saliva or blood on the vocal cords during an intermediate phase of anesthesia. Laryngospasm is a vocal cord reflex which closes the cords to protect the trachea from aspirating fluid into the lungs. When the vocal cords remain closed, no oxygen can pass and an individual can die. The Difficult Airway Society Guidelines for the Management of Tracheal Extubation (see below), published in 2012, recommend to “wait until awake, eye opening/obeying commands,” just as my faculty member advised me in 1986.
Difficult Airway Society Guidelines “low risk” algorithm
NOTE: “Wait until awake (eye opening/obeying commands)”
  • A 40-year-old male presented for outpatient surgery on his nose. His past medical history was positive for obesity (220 pounds, 5 feet 6 inches tall) and hypertension. Anesthesia was induced with propofol, fentanyl, and rocuronium, and an ET tube was easily placed. The surgery concluded 2 hours later and the anesthetics were discontinued. The patient began to cough. The anesthesiologist decided to extubate the trachea at that time. After extubation the patient continued to make respiratory efforts, but no airflow was noted. The blood oxygen saturation dropped to a dangerous level of 78%. The anesthesiologist was unable to reintubate the trachea due to poor visibility. The oxygen saturation dropped to 50%. Seven minutes later, the anesthesiologist was finally able to replace the ET tube. Copious secretions were suctioned out of the tube, ventilation remained difficult, and the oxygen saturation level remained in the 50% range. The patient’s ECG deteriorated into a cardiac arrest. He was resuscitated, and 20 minutes later his oxygen saturation finally rose to 94%. A chest x-ray showed pulmonary edema, meaning that the lungs were full of fluid. The diagnosis was laryngospasm leading to negative pressure pulmonary edema. When a patient powerfully attempts to inhale against the obstructed vocal cords of laryngospasm, the negative pressure of each inhale moves fluid from blood vessels into the airway spaces of the lungs, a phenomenon is called negative pressure pulmonary edema. This patient was eventually declared brain dead due to prolonged his prolonged low oxygen levels.
Chest X-ray showing increased lung water in negative pressure pulmonary edema
  • A 40-year-old male presented for a routine elective upper GI endoscopy procedure. He was morbidly obese, with a weight of 380 pounds and a height of 5 feet 4 inches. The anesthesiologist induced anesthesia with propofol and paralyzed the patient with rocuronium in order to place the ET tube prior to the procedure. The procedure lasted only 15 minutes. The paralysis was reversed by the drug combination of neostigmine 5 mg and Robinul 1 mg, and patient was extubated awake. In the first minute it became clear that the patient was still partially paralyzed and unable to ventilate himself. The blood oxygen level dropped acutely to life-threatening levels. The anesthesiologist then performed an emergency reintubation to replace the ET tube to again ventilate oxygen into the patient’s lungs to save his life. (Note- this case occurred in 2015, prior to the availability of sugammadex, a new intravenous drug which rapidly and reliably reverses rocuronium paralysis in a minute or less.) 
  • An 80-year-old female presented for elective right elbow surgery. She was obese (220 pounds, 5 feet tall), had a past history of congestive heart failure, and had her aortic valve replaced two years earlier. She had a history of shortness of breath climbing one flight of stairs. The anesthesiologist induced anesthesia with propofol and rocuronium, and placed an ET tube. At the conclusion of surgery, the anesthetics were discontinued. While the ET tube remained in place, her blood pressure climbed to a high of 200/120, her heart rate climbed to 120 beats per minute, and white froth began to occlude the inside of the ET tube. This fluid was pouring out of her lungs due to acute congestive heart failure caused by marked hypertension. During extubation, 10 – 30 % increases in both heart rate and blood pressure can occur. Hypertension and increased heart rate must be monitored and treated during the extubation of patients with cardiac disease. The patient was ventilated with 100% oxygen, an arterial line was placed in the radial artery in her wrist to continually monitor her elevated blood pressure, and an emergency infusion of an ICU antihypertensive drug called nitroprusside was started. The nitroprusside decreased the blood pressure to 150/80, she was re-sedated with propofol, and she was transferred to an ICU with the ET tube still in place. A myocardial infarction was ruled out by blood tests. The ET tube was removed in the ICU the following morning. She walked out of the hospital two days later. 
  • A healthy 4-year-old female had a general anesthetic for elective surgery to reconstruct her middle ear. After a ninety-minute surgery, the anesthetics were discontinued. Five minutes later she opened her eyes. Just seconds prior to the planned extubation, the patient vomited 100 milliliters of brown solid and liquid material which overflowed from her mouth. The anesthesiologist inserted a suction catheter into her mouth to remove the vomitus. The lung examination with a stethoscope confirmed normal breath sounds. The patient’s vital signs remained normal and the ET tube was removed. The patient suffered no respiratory distress, and the lungs were free from of the stomach contents. The cuffed ET tube prevented aspiration of the vomitus into her lungs. If her ET tube had been removed at any point prior to the vomiting, it’s likely the solid and liquid stomach contents would have descended into her lungs, clogged and obstructed her lower airways, and required insertion of a new ET tube and transfer to an ICU for treatment of aspiration of stomach contents into the lungs. 

My advice to anesthesia professionals regarding extubation is to:

  • Review the Difficult Airway Society Guidelines for the Management of Tracheal Extubation. The guidelines advise awake extubation. My advice, in line with this publication, is: The ET tube is your friend. Don’t pull it out until you’re certain you don’t need it any more. Prior to extubation, many patients will struggle and move prior to the time they open their eyes or can obey commands. An onlooking surgeon will at times say, “can you take the tube out now? The patient is going to rip their sutures out or have bleeding from the surgical site.” At times anesthesiologists will comply and remove the ET tube earlier at this request. Most of the time there will be no serious complication, but there will at times be complications of airway obstruction, laryngospasm, or low oxygen levels. If a bad outcome occurs, the anesthesiologist will own the complication. No one will blame the surgeon.
  • Pass the American Board of Anesthesiologists oral board examination, and become board-certified in anesthesiology. The time spent studying for the oral boards will make you a safer and smarter anesthesiologist who is better prepared to handle emergency situations. A study in Anesthesiology showed rates for death and failure to rescue from crises were greater when anesthesia care was delivered by non-board certified midcareer anesthesiologists. In the Stanford Department of Anesthesiology, we administer mock oral board examinations to the residents and fellows twice a year. Managing a sudden hypoxic episode is a common question during the oral exam. If you can think well in a room in front of two examiners, you are more likely to think well in a true emergency when your patient’s life is at stake.
  • If you have access to anesthesia simulator sessions, enroll yourself. Like the flight simulator training that commercial pilots are required to complete, anesthesia simulators hone the emergency skills of individual anesthesiologists.

What if you’re a patient and you’re contemplating surgery? How can you optimize your chances to avoid an anesthetic complication? I offer these suggestions:

  • Choose to have your surgery at a facility that is staffed with American Board of Anesthesiology board-certified physician anesthesiologists.
  • Ask a knowledgeable medical professional to recommend a specific anesthesiologist at your facility, and request that specific anesthesiologist for your care.
  • Inquire about who would manage your crisis if you have one during or after your surgery. Will your anesthesia professional be a physician anesthesiologist, a Certified Registered Nurse Anesthetist (CRNA), or an anesthesia care team made up of both? If an anesthesia care team is attending to you, how many rooms is each physician anesthesiologist supervising? How far away or how many minutes away will your physician anesthesiologist be while you are asleep?
  • In the future, quality of care data will be available on facilities and physicians, including anesthesiologists. These metrics will allow patients to compare facilities and physicians. Do your homework with whatever data is publicized. Research the facility you are about to be anesthetized in.
  • You are a higher risk patient if you have: significant obesity, obstructive sleep apnea, heart problems, breathing problems, age > 65, if you’re having regular dialysis, emergency surgery, abdominal surgery, chest surgery, major vascular surgery, cardiac surgery, brain surgery, regular dialysis, a total joint replacement, or a surgery involving a high blood loss. Be aware you’re at a higher risk, and ask more questions of your surgeon and your anesthesia provider. 

Neither anesthesia providers nor patients want to be victims of an anesthetic emergency that leads to a bad outcome.

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