HOW TO WAKE UP PATIENTS PROMPTLY FOLLOWING GENERAL ANESTHETICS

Two patients arrive simultaneously in the recovery room following general endotracheal anesthetics. One patient is unresponsive and requires an oral airway to maintain adequate respiration. In the next bed, the second patient is awake, comfortable and conversant.

How can this be? It occurs because different anesthetists practice differently.

Does it matter if a patient wakes up promptly after general anesthesia? It does. An awake, alert patient will have minimal airway or breathing problems. When it’s time to walk away from your patient in the recovery room, you’ll worry less if your patient is already talking to you and has minimal residual effects of general anesthesia. Whether the surgery was a radical neck dissection, a carotid endarterectomy, a laparotomy, or a facelift, it’s preferable to have your patient as awake as possible in the recovery room.

What can you do to assure your patients wake up promptly? A Pubmed search will give you little guidance. There’s a paucity of data or evidence in the medical literature on how to wake patients faster. You’ll find data on ultra-short acting drugs such as propofol and remifentanil. This data helps, but the skill of waking up a patient on demand is more an art than a science. Textbooks give you little advice. Anesthesiologist’s Manual of Surgical Procedures, (4^th Edition, 2009), edited by Jaffe and Samuels, has an Appendix that lists Standard Adult Anesthetic Protocols, but there is little specific information on how to titrate the drugs to ensure a timely wakeup.

Based on 29 years of administering over 20,000 anesthetics, this is my advice on how to wake patients promptly from general anesthesia:

1. Propofol. Use propofol for induction of anesthesia. You may or may not choose to infuse propofol during maintenance anesthesia (e.g. at a rate of 50 mcg/kg/min) but if you do, I recommend turning off the infusion at least 10 minutes before planned wakeup. This allows adequate time for the drug to redistribute and for serum propofol levels to decrease enough to avoid residual sleepiness.
2. Sevoflurane. Sevoflurane is relatively insoluble and its effects wear off quickly when the drug is ventilated out of the lungs at the conclusion of surgery. I recommend a maintenance concentration of 1.5% inspired sevoflurane in most patients. I drop this concentration to 1% while the surgeon is applying the dressings. When the dressings are finished, I turn off the sevoflurane and continue ventilation to pump the sevoflurane out of the patient’s lungs and bloodstream. The expired concentration will usually drop to 0.2% within 5-10 minutes, a level at which most patients will open their eyes.
3. Nitrous oxide. Unless there is a contraindication (e.g. laparoscopy or thoractomy) I recommend you use 50% nitrous oxide. It’s relatively insoluble, and adding nitrous oxide will permit you to utilize less sevoflurane. I recommend turning off nitrous oxide when the surgeon is applying the dressings at the end of the case, and turning the oxygen flow rate up to 10 liters/minute while maintaining ventilation to wash out the remaining nitrous oxide.
4. Narcotics. Use narcotics sparingly and wisely. I see overzealous use of narcotics as a problem. Prior to inserting an endotracheal tube, it’s reasonable to administer 100 mcg of fentanyl to a healthy adult or 50 mcg of fentanyl to a geriatric patient. This dose serves to blunt the hemodynamic responses of tachycardia or hypertension associated with larynogoscopy and intubation. Bolusing 250 mcg of fentanyl prior to intubation is an unnecessary overdose. The use of ongoing doses of narcotics during an anesthetic depends on the amount of surgical stimulation and the anticipated amount of post-operative pain. You may administer intermittent increments of narcotic (I may give a 50-100 mcg dose of fentanyl every hour) but I recommend your final narcotic bolus be given no less than 30 minutes prior to the anticipated wakeup. Undesired high levels of narcotic at the conclusion of surgery contribute to oversedation and slow awakening. If your patient complains of pain at wakeup, further narcotic is titrated intravenously to control the pain. Your patient’s verbal responses are your best monitor regarding how much narcotic is needed. Your goal at wakeup should be to have adequate narcotic levels and effect, but no more narcotic than needed.
5. Intra-tracheal lidocaine. I recommend spraying 4 ml of 4% lidocaine into the larynx and trachea at laryngoscopy prior to inserting the endotracheal tube. I can’t cite you any data, but it’s my impression that patients demonstrate less bucking on endotracheal tubes at awakening when lidocaine was sprayed into their tracheas. Less bucking enables you to decrease anesthetic levels further while the endotracheal tube is still in situ.
6. Local anesthetics. Local anesthetics are your friends at the conclusion of surgery. If the surgeon is able to blunt post-operative pain with local anesthesia or if you are able to blunt post-operative pain with a neuroaxial block or a regional block, your patient will require zero or minimal intravenous narcotics, and your patient will wake up more quickly.
7. Muscle relaxants. Use muscle relaxants sparingly. Nothing will slow a wakeup more than a patient in whom you cannot reverse the paralysis with a standard dose of neostigmine. This necessitates a delay in extubation until muscle strength returns. Muscle relaxation is necessary when you choose to insert an endotracheal tube at the beginning of an anesthetic, but many cases do not require paralysis for the duration of the surgery. When you must administer muscle relaxation throughout surgery, use a nerve stimulator and be careful not to abolish all twitch responses. Avoid long-acting paralyzing drugs such as pancuronium, as you will have difficulty reversing the paralysis if surgery concludes soon after you’ve administered a dose. Use rocuronium instead. Avoid administering a dose of rocuronium if you believe the surgery will conclude within the next 30 minutes—it may be difficult to reverse the paralysis, and this will delay wakeup.
8. Laryngeal Mask Airway (LMA). When possible, substitute an LMA for an endotracheal tube. Wakeups will be smoother, muscle relaxants are unnecessary, and narcotic doses can be titrated with the aim of keeping the patient’s spontaneous respiratory rate between 15- 20 breaths per minute.
9. Temperature monitoring and forced air warming. Cold is an anesthetic. Strive to keep your patient normothermic by using forced air warming. If your patient’s core temperature is low, wakeup will be delayed.

10. Consider remaining in the operating room after surgery until your patient is awake enough to respond to verbal commands. This is my practice, and I recommend it for safety reasons. In the operating room you have all your airway equipment, drugs, and suction at your fingertips. If an unexpected emergence event occurs, you’re prepared. If an unexpected emergence event occurs in an obtunded patient in the recovery room, your resuscitation equipment will not be as readily available. If your patient is responsive to verbal commands in the operating room, your patient will be wakeful on arrival in the recovery room.

Is this protocol a recipe? Yes, it is. You’ll have your own recipe, and your ingredients may vary from mine. You may choose to administer desflurane instead of sevoflurane. You may choose sufentanil, morphine, or meperidine instead of fentanyl. My advice still applies. Use as little narcotic as is necessary, and try not to administer intravenous narcotic during the last 30 minutes of surgery. If you use a remifentanil infusion, taper the infusion off early enough so the patient is wakeful at the conclusion of surgery.

The principles I’ve recommended here are time-tested and practical. Follow these guidelines and you’ll experience two heartwarming scenarios from time to time:  1) Patients in the recovery room will ask you, “You mean the surgery is done already? I can’t believe it,” and 2) Recovery room nurses will ask you, “Did this patient really have a general anesthetic?  She’s so awake!”

Your chest will swell with pride, and you’ll feel like an artist. Good luck.