When RSI isn't the Right SI

When RSI Isn't The Right SI.001

Rapid sequence intubation, the simultaneous administration of a paralytic and induction agent immediately followed by laryngoscopy, provides the optimal view of the glottis and prevents emesis. RSI is the best strategy for most patients who require intubation, but not all.

When you’ve decided to intubate, first maximally preoxygenate. If the patient will not cooperate with your preoxygenation plan, even after you’ve asked nicely, that’s your cue to add cooperation in a vial, ketamine, and then oxygenate, before you push the paralytic and intubate. This is delayed sequence intubation. Otherwise, carry on with preoxygenation, and consider a couple of special situations.

The first is the patient who is about to arrest–obtunded, no blood pressure. Any induction agent will cause sympatholysis which, along with the transition to positive pressure ventilation, may precipitate arrest, so ideally we would avoid both while the patient is in the state of nearly arrested. Resuscitate aggressively with fluids, vasoactive drips and treatment of the underlying problem for as long as you can before intubating. If you must intubate the patient who is obtunded with no blood pressure, the safest way to do it is often without any drugs at all, while the patient continues to breathe. If you have to give meds, dose sedatives low and paralytics high.

The next special situation is the patient who has a severe oxygenation or ventilation deficit. The severe oxygenation deficit patient saturates less than 90% on 100% NIV; the severe ventilation deficit patient is compensating for a severe metabolic acidosis, e.g. DKA with pH 6.7. In patients with a severe oxygenation or ventilation deficit, even a brief period of apnea is very dangerous, and since paralysis is certain to cause apnea, it stands to reason that paralysis may not be the best approach. However, these patients are very ill, so conventional awake technique, which requires time and cooperation, will not work well. If only there were a drug that would immediately render the patient tolerant of laryngoscopy, while ventilation and airway reflexes are preserved.

Ketamine-supported intubation, KSI, is pushing an induction dose of ketamine over 20-30 seconds, then performing laryngoscopy. KSI is awake intubation with minimal or no local anesthesia, or, if you prefer, RSI without paralysis.

By omitting the paralytic, KSI carries a chance of two harms: suboptimal view of the glottis, and emesis/aspiration. I address these harms in detail in this discussion; the advantage in glottic exposure offered by paralysis is less significant in the era of video laryngoscopy, which almost always provides a great view of the cords, and the risk of emesis/aspiration is very small most of the time. In any case, these harms must be weighed against the harm of apnea for the patient in front of you. Others have described a similar strategy, augmenting ketamine with etomidate as necessary.

The last and most important special situation is high concern for difficult laryngoscopy. You assess all your endotracheal tube-requiring patients for difficult laryngoscopy, either intuitively or explicitly, and most of the time, you think, I got this, in which case, carry on with RSI like you always do. But if you think it is likely that laryngoscopy will fail, and the patient is presently benefiting from their own ventilatory efforts, abolishing those efforts with RSI may not be the best choice.

Even in scary laryngoscopy cases, RSI is probably still optimal if the patient is high risk to vomit (has been vomiting, upper GI bleed, bowel obstruction). In these scenarios, the protection against emesis afforded by paralysis is compelling, so proceed with RSI, but use a double setup, with your partner on standby, ready to cut the neck. Keep the head of the bed up and drop an NG tube in beforehand if you can.

The patient whose airway is a lawyer’s dream and isn’t a particular risk to vomit is ideally intubated without a paralytic, while continuing to breathe, awake intubation. Awake intubation has two pharmaceutical arms: local anesthesia, and systemic sedation. The more cooperative the patient and the less urgent the airway, the more you can rely on local anesthesia. So if you have time and cooperation, dose glycopyrrolate or atropine, then generously nebulize, topicalize, and atomize lidocaine, then you can slowly, carefully do your laryngoscopy, or flexible endoscopy, or whatever you want, as the patient is awake and breathing. In the OR, where patients and physicians are stable and cooperative, patients with concerning airways are intubated with minimal or no sedation at all, which affords an enormous margin of procedural safety. Patients being intubated in the ED are of course neither stable nor cooperative, but a similar degree of safety can be achieved using ketamine: the less time and less cooperation, the less lidocaine, the more ketamine.

In the extreme version of the emergency department awake intubation, give induction dose ketamine and go: KSI. Consider KSI for your severe oxygenation/ventilation deficit patients, but also when you are concerned that laryngoscopy is going to fail and the patient won’t cooperate with, or you don’t have time for, a more civilized, operating theater-type awake intubation. Have a paralytic ready in syringe, in case you want to convert to RSI at any point, and incorporate a double setup component to your approach, because your concerns about laryngoscopy might turn out to be well-founded.

Awake Intubation: A Very Brief Guide



Awake intubation is placing an endotracheal tube in the trachea while the patient continues to breathe. The principle advantage over RSI is that you do not take away the patient’s respirations or airway reflexes, which makes the process safer in many circumstances. The disadvantages are that the patient’s personality and movements, as well as the patient’s airway reflexes, must be managed, which takes time, and even when done well, the view you get won’t be as good as in a paralyzed patient.  Instrumenting the back of the throat may cause gagging and possibly vomiting, though this is quite unlikely to lead to clinically significant aspiration (because the patient is awake).  The more difficult airway features, and the less urgent the intubation, the more likely you should intubate awake. Patients who are at high risk to vomit are not good candidates for an awake technique.

The two arms of awake intubation are local anesthesia and systemic sedation. The more cooperative your patient, the more you can rely on local; perfectly cooperative patients can be intubated awake without any sedation at all. More commonly in the ED, patients will require sedation. Ketamine is the agent of choice in most circumstances, as it sedates without depressing respiration or airway reflexes. In somewhat cooperative patients, 20 mg boluses, titrated to effect, work very well. In very uncooperative/agitated patients, a full dissociative dose (1.5 mg/kg) is an effective strategy though a brief period of apnea is usual if dissociative doses are delivered as a bolus, and laryngospasm is a possible complication. For those patients where raising heart rate or blood pressure is undesirable, benzodiazepine sedation will have a less effective but still salutary effect. Dexmedetomidine is probably a better agent in these scenarios, but is a little tricky to use and not available in most EDs.

Even if using full dissociative dose ketamine, do your best to anesthetize the airway, using the steps listed in the box above, excerpted from the ED intubation checklist. Local is much facilitated by a dry mucosa, so the first step, if possible, is to dry the mucosa with glycopyrolate or atropine, followed by suction and dabbing with gauze. Once this is done, anesthesia is delivered by nebulization, atomization (ideally using a purpose-built atomizer like a MAD device), and drip techniques.

Once the patient is adequately anesthetized/sedated, you gently proceed with your intubation method of choice. When you see the cords, you can pass the tube without paralysis, place the bougie and then paralyze, or paralyze before placing the bougie/tube. I recommend the second option, and I also recommend that you prepare to do a full RSI, with whatever equipment and drugs you would use in an RSI case.

When done well, awake intubation is quite anticlimactic, as the patient simply continues to breathe, and saturation is maintained, for as long as needed. While RSI is terrific and will work very well in most cases, if you perform RSI on a patient who was a good candidate for an awake technique, and it doesn’t go well, you have made a consequential mistake. Awake technique requires little additional skill; it is under-utilized in emergency medicine because it requires what emergency providers often lack: patience. In this case, however, patience is well rewarded.

The Role of Percutaneous Cricothyrotomy: Wire In Trachea Readiness Technique

There was a period in the history of emergency medicine when cricothyrotomy was the primary airway management strategy for all patients in cervical spine precautions. We have since learned that most of these patients can be intubated orally, but in the intervening years have lost our nerve when it comes to using the neck for airway access. Today, everyone agrees that the most important error around emergency cricothyrotomy is that it is performed too late [1, 2, 3]. An unsuccessful cricothyrotomy performed at the right time is defensible; a successful cricothyrotomy performed too late is indefensible. Both lead to terrible outcomes: one is good, defensible care, the other is poor, indefensible care. The pivotal element in emergency surgical airway decision-making is giving yourself permission to initiate the procedure before the patient is dead.



The Cricothyrotomy Menu

There are a variety of strategies for accessing the trachea via the neck and the terminology is confusing. Open cricothyrotomy, often referred to as surgical cricothyrotomy, is using a knife to cut a hole in the cricothyroid membrane and placing a tracheostomy tube or endotracheal through that hole. Several techniques have been described, including the no-drop technique, the rapid four-step technique, and the scalpel-bougie technique.

Percutaneous cricothyrotomy is a term usually used in distinction to surgical or open cricothyrotomy, implying a less invasive approach. Percutaneous cricothyrotomy facilitates the placement of a tracheostomy or endotracheal tube in the trachea by using either a Seldinger tube-over-dilator-over-wire technique, or a tube-over-trocar device [1, 2]. Most emergency physicians are referring to the Seldinger technique when they use the term percutaneous cricothyrotomy.

Though a needle is used in the Seldinger technique, the term needle cricothyrotomy usually refers to a less definitive procedure where a comparatively small cannula, such as a 14g angiocath, is placed into the trachea and oxygen is insufflated under pressure through the cannula; this is called transtracheal jet ventilation when a special high-flow device is used, though a bag-valve-mask is more likely to be available, if less effective, and several hard to remember maneuvers are commonly proposed that allow a BVM to be adapted for this purpose.

Wire In Trachea Readiness Technique

For patients who suddenly and unexpectedly cannot be intubated or oxygenated, the weight of evidence and opinion seems to favor an open technique [1, 2, 3, 4, 5], which appears to be faster than a percutaneous approach, more likely to be successful for those who don’t perform the procedure often (i.e. everyone), and would be used to rescue a failed percutaneous attempt. Smart people disagree on this point, however. Certainly, the goal in these scenarios is to establish oxygenation as quickly as possible by whatever means necessary, and that will differ based on provider, patient, and setting. Have a plan that works for you in your environment.

Many patients who cannot be intubated orally do not suddenly and unexpectedly crash, however. The need for a surgical airway can present itself as a land mine that explodes in front of you as you walk to your mailbox in your bathrobe, but also as a land mine that explodes as you carefully traverse a known minefield in a tank. Of course every emergency intubation is a minefield, and being cognitively and materially prepared for failure of intubation and failure of ventilation at the outset of every case is one of the characteristics of the airway expert. But while we have many options for plan A and plan B, there is still only one plan C – when intubation fails, and oxygenation fails, plan C is cricothyrotomy. Since it is clear that the most important surgical airway error is that it is delayed, several airway management paradigms [1, 2, 3] have recently emerged that explicitly encourage providers to prepare for and properly initiate cricothyrotomy.

In Scott Weingart’s CricCon taxonomy, the highest alert posture is to cut the skin and find the membrane, so that if the need arises, incising the membrane and placing the tube is simple. Most emergency practitioners, however, are uninterested in cutting the neck. On the other hand we are perfectly happy to put wires and tubes in the neck, and do it all the time in the internal jugular vein. Here lies the role of percutaneous cricothyrotomy: not as a crash technique, but as an alert posture, a readiness maneuver: when the likelihood of requiring a surgical airway is sufficiently high, place a wire in the trachea.

Placing a wire in the trachea feels more like inserting a central line than cutting the neck. Feel free to use ultrasound. [1, 2, 3] The strength of the wire-in-trachea approach is that it lures the practitioner into preparation and makes timely performance of cricothyrotomy more likely by breaking the procedure into agreeable steps. Inclination via incrementalism.

There are at least two scenarios in which wire-in-trachea readiness technique would be used:

a. An almost crash expected very difficult laryngoscopy, such as an angioedema patient who requires an airway not this very second but urgently.  If the patient is cooperative, wire is placed after rapid local anesthetic infiltration as preparations are being made for awake laryngoscopy vs. RSI. If uncooperative, wire is placed immediately after induction (concurrent with preoxygenation if using a delayed sequence strategy), just before laryngoscopy, or as laryngoscopy is beginning. This is basically an enhanced double setup.

b. In the midst of a can’t intubate, can ventilate situation. This occurs relatively commonly: laryngoscopy has failed, but LMA or bag-mask ventilation is effective, then the second laryngoscopy attempt fails, but ventilation remains effective, and then the third attempt fails, and you feel like you’re running out of tricks/tools. And you know that with every airway attempt, the glottis becomes a little more swollen, the airway gods–who have until now granted you the gift of ventilation–their patience is a little more tested, and the prospect of can’t intubate, can’t ventilate looms. So after a few failed oral attempts, while the patient is being ventilated, place the wire, then go on with as many further attempts as you want, knowing that if and when ventilation becomes ineffective (or if you have other patients to see and want to move on), cricothyrotomy is straightforward.


Percutaneous cricothyrotomy kits are expensive and often stocked in small numbers. To utilize the wire-in-trachea readiness technique, use the needle/syringe/wire from a central line kit. Fill the syringe halfway with water/saline so that tracheal location of the needle can be confirmed by the bubbling of aspirated air.

Have your unopened percutaneous cric kit at the bedside, and when needed, 1) open the kit 2) stab the skin with the scalpel 3) slide the tracheostomy tube-over-dilator into the trachea 4) pull the wire and dilator 5) inflate the cuff 6) ventilate. Don’t forget to load the tracheostomy tube onto the dilator if not pre-loaded in your kit.

Step 2 is important: an aggressive stab must be made on the skin, along the path of the wire, similar to central line technique but larger, to accommodate a larger device.

Step 3, inserting the tube-over-dilator, is facilitated, like everything else, by the application of sterile lubricant. Use a firm twisting motion.

If oral or nasal access is successful and cricothyrotomy isn’t needed, simply pull the wire. Put a band-aid on the site; this will serve as evidence of a disarmed land mine.

emupdates ETI Plan ABC


Thanks to Rob and Scott for helping me develop this idea.

The Emergency Department Double Setup


The double setup is an airway management strategy conventionally carried out in the operating room, in a stable or relatively stable patient who requires a definitive airway but is anticipated to be very difficult to intubate orally. An otolaryngologist or other surgeon fully prepares to perform a cricothyrotomy or tracheotomy–patient prepped, all equipment laid out, sterile gown and gloved, scalpel in hand–and then gives the anesthesiologist the nod, at which point the patient is induced and orotracheal intubation is attempted. If unsuccessful, anesthesia nods to surgery, who proceeds with a neck incision.

Emergency physicians are trained to manage difficult oral airways and perform cricothyrotomy–how does the double setup apply to our environment? Once the decision to intubate has been made and preoxygenation has been initiated (don’t forget the nasal cannula), ask two questions: How urgently must this patient be intubated? How difficult do I predict this airway to be?


Scenario 1: Must intubate immediately, very scary airway.

Some patients need to be intubated right now, and some patients who need to be intubated right now also are predicted to have difficult airways. The paradigmatic examples of this stressful situation are the dynamic airway insults: patients with bullets, bites or burns (neck trauma, anaphylaxis, airway burn or caustic exposure) who are already showing signs of airway embarrassment. The proper mentality in these cases is this patient is going to require cricothyrotomy, but I’m going to attempt orotracheal intubation, just to make sure. There is no time for a fancy airway assessment or fancy preparations, these patients are a test of your department’s, and your own, usual state of readiness. Patients with dynamic airways should be induced and paralyzed, because intubation will get harder with each passing minute–RSI gives you optimal conditions, as quickly as possible. Once the tools you need to perform cricothyrotomy are at the bedside, use the orotracheal technique that, in your hands, will give you your best shot at first pass success, as quickly as possible. Video laryngoscopy is a good choice. As soon as your first pass fails and not one second later, attempt ventilation (I suggest you move straight to an LMA), but you have accepted that there is a good chance that this is also unlikely to succeed and that the next step is to cut the neck. You must give yourself permission to initiate a surgical airway early in this group. An unsuccessful cricothyrotomy performed at the right time is defensible; a successful cricothyrotomy performed too late is indefensible. Both lead to terrible outcomes, one is defensible, one indefensible. Scenario 1 is an anesthesiologist’s technique compressed into an emergency physician’s timeline.


Scenario 2: Must intubate immediately, no difficult airway features. 

Lots of ED patients fall into this category, perhaps the most typical is the CNS catastrophe who presents with a GCS that can be counted on one hand. Like scenario 1, the airway attempt must proceed without extensive preparation, but both orotracheal intubation and ventilation are more likely to be successful, and this procedural reserve affords you a more measured approach. Be mindful, however, that your brief airway assessment may mislead you, and that you never know what you’re going to get when you put in the laryngoscope. You therefore have decided, before you push drugs and put in the laryngoscope, what you will do when laryngoscopy fails, and what you will do when ventilation fails, and you have the materials at the bedside to do it. Experienced emergency providers recognize procedural reserve as a luxury that the patient can revoke immediately and unpredictably, and are thus ready to transition to a scenario 1 type approach every time they push a paralytic.


Scenario 3: No urgency to intubate, very scary airway. 

When you have time to intubate, you are swimming in the anesthesiologist’s ocean and you need to use a different stroke; in fact swimming like an anesthesiologist is mostly about wearing several life jackets and surrounding yourself with lifeguards. This scenario might involve a patient with a fixed flexion deformity of the cervical spine who is slowly decompensating from a pneumonia, or a patient with an airway tumor who just took 20 long-acting diltiazem tablets and needs gastric lavage. Calling an anesthesiologist is reasonable in these cases and certainly is the right answer on an oral board exam, but an anesthesiologist may not be available (and certainly will not be available on the boards).

The approach for these patients centers on being cognitively and materially ready for plan A, B, C, and D and on awake technique. It’s also nice to have a few friends at the bedside. Exactly what is plan A-D is up to you, as long as these plans are carefully prepared, and one of them is cricothyrotomy, if the patient cannot be intubated or ventilated. This picture demonstrates an example plan A, B, C, and D and a variety of best practice points.

The patient has a variety of congenital cognitive and anatomic anomalies, was very uncooperative and required intubation for emergent MRI. He is known to be a very difficult laryngoscopy. Our plan was to use an awake technique using IM ketamine sedation to augment local anesthesia.

1. Plan A is video laryngoscopy. The intubator (in the middle) made his best attempt but could not visualize the vocal cords, so without removing the device, handed off the video laryngoscope to the assistant on the patient’s left, who was already performing suction.

2. Plan B is flexible endoscopy, which is ongoing. Note that the operators are at this point using both video screens (video laryngoscope and flexible endoscope) simultaneously.

3. The second assistant on the patient’s right has access to the equipment tray and is also the designated surgical airway operator.

4. The neck is marked, and the site has been infiltrated with lidocaine and epinephrine. The more likely is cricothyrotomy, and the more time you have to prepare, the more advanced your surgical airway preparation should be.

5. The second assistant is using his finger to pull on the right corner of the mouth. This under-utilized technique really opens things up.

6. The usual suction (in this case, the second suction) under the patient’s right shoulder is available to either the intubator or second assistant. The flexible endoscope used in this case does not have suction capability, which made the need for suction on either side more likely.

7. The head of the bed is at 30 degrees.

8. The bag-mask is on the patient’s abdomen. A common mistake is to leave the bag-mask behind the operators, hanging off the oxygen tubing, so that as the saturation is dropping, someone who is already freaking out and tangled in wires and tubes has to perform a complex dance move to get at the device.

9. The intubating LMA is ready to be inserted if emergency ventilation is required. This is our Plan C. Plan D is cricothyrotomy (either carefully if Plans A/B/C have failed but oxygenation is adequate, or quickly at any moment if intubation and oxygenation fail).

10. A variety of tubes and blades, as well as oral and nasal airways.

11. The medications and tools we used to anesthetize the airway.

12. Post-intubation equipment.

13. The ventilator is on standby, connected to end-tidal CO2 (not visible) and programmed with patient-appropriate settings.

14. This container holds our supply of bougies and is sadly empty. There is a bougie on a stand behind the video laryngoscope, not visible but easily accessible to the assistant on the patient’s left.

15. Don’t forget to use a checklist.


Scenario 4: No urgency to intubate, no difficult airway features. 

Here we’re talking about the slowly worsening guillain-barré patient, or the patient with the small subdural that the receiving hospital has asked you to intubate for transport. Seems like low risk, and it is low risk, for the patient. But these cases are actually higher risk for you, because when a patient arrives in extremis, your hand is forced and if it doesn’t go well, it’s harder to hold you responsible. In a well patient with normal anatomy who needs to be intubated, you are again in anesthesiologist territory, and you are potentially held to the higher standard of an anesthesiologist, who gets called into the chief’s office when the patient wakes up with a chipped tooth. These are great cases to practice your awake technique; you might find that you don’t mind swimming with a life jacket every once in a while.



Emergency Department Intubation Checklist v13

vector image for screen viewing

acrobat document for printing

Changes in v13:

  • nasal cannula and preoxygenation sections beefed up
  • added airway management strategy section
  • removed incremental FiO2/PEEP chart
  • roc dose changed from TBW to IBW
  • added section on cricothyrotomy technique
  • ultrasound added to post-intubation complications assessment
  • added proviso, “pretreatment agents are always optional.”
  • added S to DOPES mnemonic (breath stacking)
  • added “function” to “verify cuff” for ETT
  • changed phenylephrine from post to peri intubation hypotension
  • fancy style enhancements

Bonus: personnel arrangement diagram

The High Flow Nasal Cannula in the Emergency Department

Those of you who have adopted the strategy of Nasal Oxygen During Efforts at Securing A Tube know how powerful this technique is, and know that there is no reason not to take advantage of apneic oxygenation by applying nasal cannula oxygen during every airway management case. After observing the effect of this technique a few times, you may have shaken your head at all the unnecessary catecholamines released by you and your patients over the years as you or your trainee hunted around for cords as the saturation fell. But there’s also a small part of you that is glad to have been part of this earlier era, when intubating in the emergency department was a harrowing combination of skill, brute force, and luck. When intubating in the emergency department left providers drenched in sweat and epinephrine, hands trembling, wired and exhausted. When intubating in the emergency department felt like saving a life.


These days, with all the fancy airway tools and techniques, placing an endotracheal tube in the trachea often feels as dramatic as placing a foley in the urethra. Your hard-fought airway skills and intestinal fortitude seem wasted. You might find yourself obscuring your intern’s view by “applying cricoid pressure” just to watch him get that same panic-induced nausea you had to suffer day in day out, all those years, glidescope be damned. Intubation these days is too friggen easy. Well it’s about to get even easier.

The high flow nasal cannula is a device that has been used by neonatologists for some time, but is now making its way into adult medicine. By using special tubing, warming, and humidification, the device allows for the nasal adminstration of oxygen at upwards of sixty (60) liters per minute. This enables the delivery of 100% oxygen fraction and true positive pressure, up to around six centimeters water of PEEP. The apparatus itself has a relatively small footprint and is easier to set up than non-invasive ventilation. The oxygen hose connects to a seperate valve on the wall-mounted flowmeter, which liberates precious oxygen sources for the bag valve mask and face mask.

Being blasted with 60 liters per minute of oxygen through your nose isn’t a pleasure, but it’s much more comfortable than NIV, and of course allows the patient to talk, eat, vomit, whatever they want. Because so much water has to be added to the air, the HFNC should not be used in patients who cannot tolerate additional volume. We will see HFNC being used in the ED on many of the COPD and pneumonia patients who linger miserably on NIV, not sick enough to require ETI but not well enough to fly on simple supplemental oxygen.

But where HFNC really shines is during RSI. Put the big cannulae into your patient’s nose and let’r rip. Add a face mask or NIV or whatever your preoxygenation pleasure, then push your meds and laugh to yourself as the saturation rises during apnea. Whistle sweetly as the intern illuminates every inch of the soft palate with great determination. Hell, go see another patient and tell him to call you when he’s given up.* You remember, though, the days of the giants. When being regarded as a skilled laryngoscopist meant something. When the word airway made internists scatter like mice. When it wasn’t so easy to save a life.



*Note that hypercapnea is a consequence of apnea seperate from hypoxia. High CO2 levels are generally tolerated well, but now that we can seemingly oxygenate the apneic patient indefinitely, remember that patients with severe acidemia or intracranial insults require the expeditious establishment of ventilation as well as oxygenation.

Intubate with the head of the bed elevated

semi fowlers position


In addition to improving laryngeal view, there is now evidence that elevating the head of the bed prolongs apneic desaturation time. This makes good sense, and the tradition of intubating patients in the supine position should be added to the long list of Things We’ve Been Doing Wrong All This Time. Using semi-fowlers position also probably reduces the risk of regurgitation/aspiration, and is strongly recommended for all patients being intubated for upper GI bleed. But make it your routine and you will benefit when that extra little bit of glottic view, those extra few seconds of apnea, and that extra bit of protection against regurgitation really matter. There is no downside.


Ramkumar 2011

Purpose Failed airway is the anesthesiologist’s nightmare. Although conventional preoxygenation can provide time, atelectasis occurs in the dependent areas of the lungs immediately after anesthetic induction. Therefore, alternatives such as positive end-expiratory pressure (PEEP) and head-up tilt during preoxygenation have been explored. We compared the conventional preoxygenation technique (group C) with 20° head-up tilt (group H) and 5 cmH2O PEEP (group P) in non-obese individuals for non-hypoxic apnea duration.

Methods A total of 45 patients were enrolled (15 in each group). After 5 min of preoxygenation, intubation was performed after induction of anesthesia with thiopentone and succinylcholine. After confirming the tracheal intubation by esophageal detector device and capnogram, all patients were administered vecuronium to maintain neuromuscular blockade and midazolam to prevent awareness. Post-induction, patients in all groups were left apneic in supine position with the tracheal tube exposed to atmosphere till the SpO2 dropped to 93% or 10 min of safe apnea was achieved.

Results The demographic data were comparable. Non-hypoxic apnea duration was higher with group H (452 ± 71 s) compared to group C (364 ± 83 s, P = 0.030). Group P did not show significant increase in the duration of non-hypoxic apnea (413 ± 86 s). There were no adverse outcomes or events.

Conclusions Preoxygenation is clinically and statistically more efficacious and by inference more efficient in the 20° head-up position than with conventional technique in non-obese healthy adults. Although application of 5 cmH2O PEEP provides longer duration of non-hypoxic apnea comparedto conventional technique, it is not statistically significant.


PMID 21293885

photo credit: http://goo.gl/yn2pq