Aneasthesia Pearls May 2014

ANAESTHESIA PEARLS

GENERAL ANESTHETICS

HOW TO WAKE UP PATIENTS PROMPTLY FOLLOWING GENERAL ANESTHETICS
Richard Novak, M.D.
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.
NAESTHETIC CONSIDERATION IN AIDS PATIENTS
How to wake patients promptly from general anesthesia :
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
References :
Theanesthesiaconsultant Blog

OPERATING ROOM

READING IN THE OPERATING ROOM
Laptops and Smartphones in the Operating Theatre
Miller’s Anesthesia (7th Edition, 2009, chapter 6)
States, “The observation that some anesthetists were observed to read journals or books casually during patient care led to a vigorous debate of the appropriateness of such activity. Although it is indisputable that reading can distract attention from patient care, there are no data at present to determine the degree to which reading does distract attention, especially if the practice is confined to low-workload portions of a case. Furthermore, many anesthetists pointed out that reading as a distraction is not necessarily any different from many other kinds of activities not related to patient care that are routinely accepted, such as idle conversation among personnel. Many comments about the issue were related not to the actual decrement in vigilance induced by reading but rather to the impact of the negative perception of the practice (and of those who do it) by surgeons and by patients (if they were aware of it)”.
In the Anesthesia Patient Safety Foundation Newsletter, Fall 2004 edition,
Dr. Terri Monk opined that reading in the OR seriously compromised patient safety. She was opposed to reading for the following reasons:
Reading diverts one’s attention from the patient.
The patient is paying for the anesthesiologist’s undivided attention, and most well-informed patients want to know if the anesthesiologist plans to turn over a portion of their anesthesia care to a nurse or resident. If we are obliged to honestly answer that concern, then, shouldn’t we also be obliged to inform the patient that we plan to read during a portion of the anesthetic?
Reading is medico-legally dangerous. Dr. Monk wrote, “Any plaintiff’s attorney would love to have a case in which the circulating nurse would testify, ‘Dr. Giesecke was reading when the cardiac arrest occurred. Yep, he was reading the Wall Street Journal. You know he has a lot of valuable stocks that he must keep track of.’ It is possible that if anesthesiologists informed their malpractice carriers that they routinely read during cases, the companies might raise premiums or cancel malpractice coverage.”
The practice of reading in the OR projects a negative public image. Nurses, technicians, and surgeons may think the anesthesiologist is less professional.
A 2012 study Jorm CM, Anaesthesia Intensive Care. 2012 Jan;40(1):71-8,
(Laptops and smartphones in the operating theatre – how does our knowledge of vigilance, multi-tasking and anaesthetist performance help us in our approach to this new distraction?) concluded there were no data concerning the effects of the use of laptops and smartphones in the operating theatre on anesthetist performance, and that these devices were now in frequent use.
The authors made the following points regarding the nature of anesthesia work and the factors that affect performance in anesthesia:
Anesthesia involves multi-tasking and the maintenance of situational awareness. Studies have shown that attending to a range of tasks simultaneously is a key characteristic of anesthetic practice, and that anesthetists are superior to non-anesthetists in performing additional tasks while monitoring patients.
Anesthetists typically only glance at monitors. Covert observations of anesthetists in British Columbia revealed subjects spent less than 5% of their time observing the monitoring display. This was made up of brief glances (1.5 to 2 seconds duration) occurring 15 – 20 times during each 10-minute segment of time.
Anesthetic work is reduced during prolonged maintenance, potentially resulting in boredom and/or secondary activities being undertaken. The maintenance phase in some anesthetics (typically cases of longer duration, lower complexity and where the patient is stable) may be a time of low workload and infrequent task demands. In a study of 105 anesthesia clinicians, half reported being bored infrequently, but 90% admitted to occasional episodes of extreme boredom. Boredom can result in severely decreased vigilance if the anesthetist is suffering from sleep deprivation.
The authors concluded there was no evidence to support a blanket prohibition on the use of smartphones and laptops in the operating theatre, and there was good reason to avoid edicts that are not supported by solid evidence. They stated, “There is no doubt that reading or computer usage gives the appearance of being less attentive, even if there are no measurable effects on routine care…Computer and phone tasks that also require immediate responses appear to provide a greater risk than reading (whether from a book or screen). While boredom may be cognitively unpleasant, there is no evidence of anesthetist boredom (in the absence of sleep) harming patients.”
Ref:
1.READING IN THE OPERATING ROOM: Theanesthesiaconsultant Blog;
2.Miller’s Anesthesia (7th Edition, 2009, chapter 6): READING IN THE OPERATING ROOM
3.Anesthesia Patient Safety Foundation Newsletter, Fall 2004 edition,
4.Laptops and smartphones in the operating theatre – how does our knowledge of vigilance, multi-tasking and anaesthetist performance help us in our approach to this new distraction? Jorm CM, Anaesthesia Intensive Care. 2012 Jan;40(1):71-8

ADVANCES AFFECTING ANESTHESIA

ADVANCES AFFECTING ANESTHESIA
THE TOP TEN MOST USEFUL ADVANCES AFFECTING ANESTHESIA IN THE PAST 25 YEARS
Richard Novak, M.D.
In 1986 the American Society of Anesthesiologists adopted pulse oximetry and end-tidal CO2 monitoring as standards of care. These two monitors were our specialty’s major advances in the 1980’s, and made anesthesia safer for everyone.
What are the most significant advances affecting anesthesia since that time?
THE TOP TEN MOST USEFUL ADVANCES AFFFECTING ANESTHESIA IN THE PAST 25 YEARS (1987- 2012):
#10. The cell phone (replacing the beeper)
Cell phones changed the world, and they changed anesthesia practice as well. Before the cell phone, you’d get paged while driving home and have to search to find a payphone. Cell phones allow you to be in constant contact with all the nurses and doctors involved in your patient’s care at all times. No one should carry a beeper anymore.
#9. Ultrasound use in the operating room
The ultrasound machine aids peripheral nerve blockade and catheter placement, and intravascular catheterization. Nerve block procedures used to resemble “voodoo medicine,” as physicians stuck sharp needles into tissues in search of paresthesias and nerve stimulation. Now we can see what we’re doing.
#8. The video laryngoscope
Surgeons have been using video cameras for decades. We finally caught up. Although there’s no need for a video laryngoscope on routine cases, the device is an invaluable tool for seeing around corners during difficult intubations.
#7. Rocuronium
Anesthesiologists long coveted a replacement for the side-effect-ridden depolarizing muscle relaxant succinylcholine. Rocuronium is not as rapid in onset as succinylcholine, but it is the fastest non-depolarizer in our pharmaceutical drawer.
#6.Ondansetron
The introduction of ondansetron and the 5-HT3 receptor blocking drugs gave anesthesiologists our first effective therapy to combat post-operative nausea and vomiting.
#5. The Internet
The Internet changed the world, and the Internet changed anesthesia practice as well. With Internet access, clinicians are connected to all known published medical knowledge at all times. Doctors have terrific memories, but no one remembers everything. Now you can research any medical topic in seconds. Some academics opine that the use of electronic devices in the operating room is dangerous, akin to texting while driving. Monitoring an anesthetized patient is significantly different to driving a car. Much of O.R. monitoring is auditory. We listen to the oximeter beep constantly, which confirms that our patient is well oxygenated.
A cacophony of alarms sound whenever vital signs vary from norms. An anesthesia professional should never let any electronic device distract him or her from vigilant monitoring of the patient.
#4. The ASA Difficult Airway Algorithm
Anesthesia and critical care medicine revolve around the mantra of “Airway-Breathing-Circulation.” When the ASA published the Difficult Airway Algorithm in Anesthesiology in 2003, they validated a systematic approach to airway management and to the rescue of failed airway situations. It’s an algorithm that we’ve all committed to memory, and anesthesia practice is safer as a result.
#3. Sevoflurane
Sevo is the volatile anesthetic of choice in community private practice, and is a remarkable improvement over its predecessors. Sevoflurane is as insoluble as nitrous oxide, and its effect dissipates significantly faster than isoflurane. Sevo has a pleasant smell, and it replaced halothane for mask inductions.
#2. Propofol
Propofol is wonderful hypnotic for induction and maintenance. It produces a much faster wake-up than thiopental, and causes no nausea. Propofol makes us all look good when recovery rooms are full of wide-awake, happy patients.
#1. The Laryngeal Mask Airway
What an advance the LMA was. We used to insert endotracheal tubes for almost every general anesthesia case. Endotracheal tubes necessitated laryngoscopy, muscle relaxation, and reversal of muscle relaxation. LMA’s are now used for most extremity surgeries, many head and neck surgeries, and most ambulatory anesthetics.
Ref:
1.THE TOP TEN MOST USEFUL ADVANCES AND THE FIVE MOST OVERRATED ADVANCES AFFECTING ANESTHESIA IN THE PAST 25 YEARS; Theanesthesiaconsultant Blog
Posted in ANAESTHESIA PEARLS 2014

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