Tag Archives: procedures

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Tube tip top tip

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I’m not sure what this offers over purpose-built supraglottic airways, but effective ventilation may be achieved after failure of mask ventilation by siting a tracheal tube with its tip in the pharynx and the cuff inflated with 20 mls. The tube ‘is gently inserted 10—14cm, dependent on patient size, or until any resistance is felt, in caudal direction by letting the tip of the tube follow the palate and the posterior pharyngeal wall (in order to place the tip of the tube posterior to the epiglottis)’. As long as the tube tip or Murphy eye is not in the oesophagus, ventilation should be possible. The hand position maintains a jaw thrust while closing the mouth and occluding the nostrils.


BACKGROUND: Mask ventilation occasionally fails. Alternative readily available and simple methods to establish ventilation in these cases are needed.

METHODS: Retrospective description of cases in which a new technique, tube tip in pharynx (TTIP) ventilation, was employed for restoring ventilation in case of failed facemask ventilation during induction of anaesthesia. The technique involves a standard endotracheal tube and can be performed single-handed: A standard endotracheal tube was placed via the mouth with the tip in the pharynx and the cuff was inflated. By placing the fourth and fifth fingers below the ramus of the mandible, the third finger below the lower lip, the second finger above the upper lip and on one side of the nose and the first finger on the other side of the nose, an open airway is restored. Chin lift is inherent in the grip, thus contributing to opening of the airway.

RESULTS: In all four cases of failed mask ventilation the anaesthetist could establish an open airway and subsequent ventilation without the need for an assistant. There were no indications of gastric insufflation.

CONCLUSION: The TTIP technique established ventilation in all four patients after abandoned facemask ventilation. The technique only involves one person and an endotracheal tube and warrants to be included in the armamentarium of anaesthetists. Further prospective studies are needed to refine the technique and delimit its indications.

Tube tip in pharynx (TTIP) ventilation: simple establishment of ventilation in case of failed mask ventilation
Acta Anaesthesiol Scand. 2005 Feb;49(2):252-6

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Two hands on the jaw for mask ventilation

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Elective surgery patients were anaesthetised with propofol with or without fentanyl and had an oropharyngeal airway placed. They were ventilated with pressure control ventilation via facemask held with a single handed traditional ‘EC clamp’ grip and with a two-handed jaw thrust, and compared. The order in which these two techniques were trialled was randomised. All breaths were delivered with a peak pressure of 15 cm H2O, an inspiratory-to-expiratory ratio of 1:1, at a frequency of 15 breaths per minute. Ventilation was more effective with the two handed technique.
Using a self-inflating bag for resuscitation, this would translate to a two-person technique. Of note in methodology however was use of a ‘standard pillow’ and some emphasis on head extension. Perhaps ventilation would have been more effective with either technique if they had applied the golden rule of ear-to-sternal-notch positioning: a must for effective mask ventilation and successful laryngoscopy.

BACKGROUND: Mask ventilation is considered a “basic” skill for airway management. A one-handed “EC-clamp” technique is most often used after induction of anesthesia with a two-handed jaw-thrust technique reserved for difficult cases. Our aim was to directly compare both techniques with the primary outcome of air exchange in the lungs.
METHODS: Forty-two elective surgical patients were mask-ventilated after induction of anesthesia by using a one-handed “EC-clamp” technique and a two-handed jaw-thrust technique during pressure-control ventilation in randomized, crossover fashion. When unresponsive to a jaw thrust, expired tidal volumes were recorded from the expiratory limb of the anesthesia machine each for five consecutive breaths. Inadequate mask ventilation and dead-space ventilation were defined as an average tidal volume less than 4 ml/kg predicted body weight or less than 150 ml/breath, respectively. Differences in minute ventilation and tidal volume between techniques were assessed with the use of a mixed-effects model.
RESULTS: Patients were (mean ± SD) 56 ± 18 yr old with a body mass index of 30 ± 7.1 kg/m. Minute ventilation was 6.32 ± 3.24 l/min with one hand and 7.95 ± 2.70 l/min with two hands. The tidal volume was 6.80 ± 3.10 ml/kg predicted body weight with one hand and 8.60 ± 2.31 ml/kg predicted body weight with two hands. Improvement with two hands was independent of the order used. Inadequate or dead-space ventilation occurred more frequently during use of the one-handed compared with the two-handed technique (14 vs. 5%; P = 0.013).
CONCLUSION: A two-handed jaw-thrust mask technique improves upper airway patency as measured by greater tidal volumes during pressure-controlled ventilation than a one-handed “EC-clamp” technique in the unconscious apneic person.

A Two-handed Jaw-thrust Technique Is Superior to the One-handed “EC-clamp” Technique for Mask Ventilation in the Apneic Unconscious Person
Anesthesiology. 2010 Oct;113(4):873-9

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Easy on the ELM

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A first report of thyroid cartilage fracture resulting from laryngoscopy and intubation has been published. An elective surgery patient underwent paralysis with 60 mg rocuronium after which ‘laryngoscopy and intubation attempts with a Macintosh 3 blade, Miller 2 blade, stylet, and vigorous external laryngeal manipulation yielded only Cormack Lehane grade 3 views of the larynx‘. Intubation was eventually achieved with a Glidescope, but it was noted that ‘external laryngeal manipulation was applied as forcefully as the assistant could perform the maneuver‘.
The author suggests the fracture could either have resulted from the external laryngeal manipulation during laryngoscopy or from the rigid curved stylet used with the Glidescope. Whichever it was, their take home advice is sound:

Even during difficult laryngoscopies, gentle manipulations are best

I would add to this – do the ELM yourself – in other words, bimanual laryngoscopy.
Laryngoscopy Complicated by Thyroid Cartilage Fracture
Anesthesiology. 2010 Oct;113(4):993-4

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African study on cricoid pressure

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The inventor of cricoid pressure. Possibly.

A colleague told me about a cricoid pressure paper I would otherwise have missed, since I don’t normally check out the International Journal of Obstetric Anaesthesia. This was a multicentre observational study in Malawi, in which 30 women (of 4891 general anaesthetics) vomited or regurgitated during induction of anaesthesia, in 24 of whom cricoid pressure was applied. 11 of the 77 deaths that occurred were associated with regurgitation, in 10 of which regurgitation contributed to the death. Nine of these 11 mothers who died had had cricoid pressure applied. The incidence of regurgitation was lower, but not significantly so, among those who did not have cricoid pressure applied. Not sure why it took nine years to publish this work.
 

BACKGROUND: Cricoid pressure is a routine part of rapid-sequence induction of general anaesthesia in obstetrics, but its efficacy in saving life is difficult to ascertain.
METHODS: As part of a prospective observational study of caesarean sections performed between January 1998 and June 2000 in 27 hospitals in Malawi, the anaesthetist recorded whether cricoid pressure was applied, the method of anaesthesia, the use of endotracheal intubation, the occurrence and timing of regurgitation and any other pre- or intra-operative complications. Logistic regression was used to assess the effect of cricoid pressure, type of anaesthetic and pre-operative complications on vomiting/regurgitation and death.
RESULTS: Data were collected for 4891 general anaesthetics that involved intubation. Cricoid pressure was applied in 61%; 139 women vomited or regurgitated, but only 30 on induction of anaesthesia, in 24 of whom cricoid pressure was applied. There were 77 deaths, 11 of which were associated with regurgitation, in 10 of which regurgitation contributed to the death. Nine of the 11 mothers had cricoid pressure applied. Only one died on the table, the rest postoperatively. All those who died had preoperative complications.
CONCLUSION: This study does not provide any evidence for a protective effect of cricoid pressure as used in this context, in preventing regurgitation or death. Preoperative gastric emptying may be a more effective measure to prevent aspiration of gastric contents.

Life-saving or ineffective? An observational study of the use of cricoid pressure and maternal outcome in an African setting
Int J Obstet Anesth. 2009 Apr;18(2):106-10

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Alfentanil for Procedural Sedation

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An evaluation of single-agent alfentanil for procedural sedation in the ED has been published by the team at Hennepin County Medical Centre. A short-acting opioid, alfentanil induces 7 to 9 minutes of pain relief after a single bolus of 10 mcg/kg, a duration of action similar to that of propofol. It produces analgesia and sedation but not amnesia. In this study of 148 adult patients, alfentanil doses and the use of supplemental oxygen were at treating physician discretion. it appeared to be effective for ED procedural sedation but displayed a rate of airway or respiratory events leading to an intervention similar to that of previous reports of deeper sedation with propofol. The authors state ‘Despite very high rates of procedural pain and recall, subjects remained highly satisfied.’

STUDY OBJECTIVE: We administer alfentanil sedation for minor procedures in the emergency department (ED), and our primary objective is to assess the incidence of airway and respiratory adverse events leading to an intervention. Our secondary goals are to assess for other adverse events, the depth and duration of sedation, the incidence of subclinical respiratory depression, and patient perceptions of the quality of the sedation.
METHODS: In this observational study of adults receiving alfentanil for ED procedures, we recorded the incidence of airway or respiratory adverse events leading to an intervention (increase/addition of supplemental oxygen, bag-valve-mask ventilation, airway repositioning, or stimulation to induce breathing). Secondary goals were assessed with monitoring (including capnography), the Observer’s Assessment of Alertness/Sedation (OAA/S) scale, and postprocedure patient visual analog scale ratings of pain, recall, and satisfaction.
RESULTS: Airway or respiratory events leading to intervention were observed in 39% of the 148 subjects (supplemental oxygen 18%, bag-valve mask 3%, airway repositioning 2%, stimulation 18%); none were clinically significant. The median OAA/S nadir was 4 (interquartile range 3 to 5). Median patient ratings were positive (pain 26 mm, recall 98, satisfaction 100 mm).
CONCLUSION: Alfentanil appears effective for ED procedural sedation but displays a rate of airway or respiratory events leading to an intervention similar to that of previous reports of deeper sedation with propofol.

Alfentanil for Procedural Sedation in the Emergency Department
Ann Emerg Med. 2011 Feb;57(2):117-21

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Midazolam smoothens adult ketamine sedation

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In adults undergoing procedural sedation with ketamine, 0.03 mg/kg IV midazolam reduced recovery agitation compared with placebo.

You don’t need this. Just give the midazolam.


STUDY OBJECTIVE: We assess whether midazolam reduces recovery agitation after ketamine administration in adult emergency department (ED) patients and also compared the incidence of adverse events (recovery agitation, respiratory, and nausea/vomiting) by the intravenous (IV) versus intramuscular (IM) route.

METHODS: This prospective, double-blind, placebo-controlled, 2×2 factorial trial randomized consecutive ED patients aged 18 to 50 years to 4 groups: receiving either 0.03 mg/kg IV midazolam or placebo, and with ketamine administered either 1.5 mg/kg IV or 4 mg/kg IM. Adverse events and sedation characteristics were recorded.

RESULTS: Of the 182 subjects, recovery agitation was less common in the midazolam cohorts (8% versus 25%; difference 17%; 95% confidence interval [CI] 6% to 28%; number needed to treat 6). When IV versus IM routes were compared, the incidences of adverse events were similar (recovery agitation 13% versus 17%, difference 4%, 95% CI -8% to 16%; respiratory events 0% versus 0%, difference 0%, 95% CI -2% to 2%; nausea/vomiting 28% versus 34%, difference 6%, 95% CI -8% to 20%).

CONCLUSION: Coadministered midazolam significantly reduces the incidence of recovery agitation after ketamine procedural sedation and analgesia in ED adults (number needed to treat 6). Adverse events occur at similar frequency by the IV or IM routes.

Ketamine with and without midazolam for emergency department sedation in adults: a randomized controlled trial
Ann Emerg Med. 2011 Feb;57(2):109-114

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Pre-hospital RSI and single use blades

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Single-use metal laryngoscope blades were compared in a randomised trial in the pre-hospital setting by French SAMU physicians. First-pass intubation success (defined as one advancement of the tube in the direction of the glottis during direct laryngoscopy) was similar between conventional and disposable metal blades.

A French doctor (not involved in the study)

STUDY OBJECTIVE: Emergency tracheal intubation is reported to be more difficult with single-use plastic than with reusable metal laryngoscope blades in both inhospital and out-of-hospital settings. Single-use metal blades have been developed but have not been compared with conventional metal blades. This controlled trial compares the efficacy and safety of single-use metal blades with reusable metal blades in out-of-hospital emergency tracheal intubation.
METHODS: This randomized controlled trial was carried out in France with out-of-hospital emergency medical units (Services de Médecine d’Urgence et de Réanimation). This was a multicenter prospective noninferiority randomized controlled trial in adult out-of-hospital patients requiring emergency tracheal intubation. Patients were randomly assigned to either single-use or reusable metal laryngoscope blades and intubated by a senior physician or a nurse anesthetist. The primary outcome was first-pass intubation success. Secondary outcomes were incidence of difficult intubation, need for alternate airway devices, and early intubation-related complications (esophageal intubation, mainstem intubation, vomiting, pulmonary aspiration, dental trauma, bronchospasm or laryngospasm, ventricular tachycardia, arterial desaturation, hypotension, or cardiac arrest).
RESULTS: The study included 817 patients, including 409 intubated with single-use blades and 408 with a reusable blade. First-pass intubation success was similar in both groups: 292 (71.4%) for single-use blades, 290 (71.1%) for reusable blades. The 95% confidence interval (CI) for the difference in treatments (0.3%; 95% CI -5.9% to 6.5%) did not include the prespecified inferiority margin of -7%. There was no difference in rate of difficult intubation (difference 3%; 95% CI -7% to 2%), need for alternate airway (difference 4%; 95% CI -8% to 1%), or early complication rate (difference 3%; 95% CI -3% to 8%).
CONCLUSION: First-pass out-of-hospital tracheal intubation success with single-use metal laryngoscopy blades was noninferior to first-pass success with reusable metal laryngoscope blades.

Out-of-Hospital Tracheal Intubation With Single-Use Versus Reusable Metal Laryngoscope Blades: A Multicenter Randomized Controlled Trial
Ann Emerg Med. 2011 Mar;57(3):225-31

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More on Rocuronium (and Sugammadex)

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While I am gradually being persuaded rocuronium might after all be a better choice than suxamethonium for rapid sequence intubation in critically ill patients- partly due to its relative preservation of apnoea time before desaturation in elective anaesthesia patients1 – I don’t believe that the existence and availability of its reversal agent, sugammadex, should really sway us in critical care. After all, we’re usually committed to getting an airway of some description (tracheal tube, supraglottic airway, or cricothyrotomy), and the relatively short duration of suxamethonium has never allowed me to ‘wake someone up and cancel the case’ in a critical care scenario. In fact, with sux, even healthy patients will desaturate before it wears off 2-4 if one is unable to intubate or ventilate.

But could we give sugammadex and reverse the rocuronium in time to save the patient in a can’t intubate/can’t ventilate (CICV) situation? This was tested in a simulation that studied the total time taken for anaesthetic teams to prepare and administer sugammadex from the time of their initial decision to use the drug5. The mean (SD) total time to administration of sugammadex was 6.7 (1.5) min, following which a further 2.2 min (giving a total 8.9 min) should be allowed to achieve a train-of-four ratio of 0.9. Four (22%) teams gave the correct dose, 10 (56%) teams gave a dose that was lower than recommended.
 
A reply to this article6 recommended some steps to speed up and improve the process:

  1. Brief the team that rocuronium is to be used and that should an unanticipated difficult airway situation be encountered, then sugammadex will be used to reverse the effects of the rocuronium.
  2. Allocate the task of drawing up the sugammadex to a specific team member who has no additional role in the rapid sequence induction.
  3. Before induction, a calculation is made of the dose of sugammadex (16 mg/kg) that would be required and the volume of drug that should be drawn up.
  4. The instruction is given that should the anaesthetist not confirm intubation within 2 min, then the sugammadex is to be drawn up and handed to the anaesthetist for administration.


There are of course rare situations where sugammadex can be a nuisance – it hangs around in renal failure and a recent case report 7described rocuronium (50mg followed by 30mg, patient weight not stated) failing to work on an elderly man who had received sugammadex 16 hours earlier! The authors of this case report state that in healthy patients, the mean cumulative percentage of sugammadex excreted in the urine over 24 h is 48–86%; therefore, a period of 24 h is recommended before a second administration of rocuronium. However, a good dose of rocuronium (1.2 mg/kg) should be effective after sugammadex reversal in previously healthy patients, but a study showed onset was slower and duration shorter if the second dose of rocuronium was given within 25 minutes of the sugammadex8.
So what are the take home points here? For me, the issues are:

  • Suxamethonium offers no real advantages over rocuronium for RSI in critical care – rocuronium at a dose of 1.2 mg/kg will provide similar intubating conditions to a good dose of sux9
  • Whatever you use, you need a rescue plan (supraglottic airway or transtracheal airway) for the CICV scenario
  • Sugammadex is a useful reversal agent in elective anaesthesia but is unlikely to be useful in a critical care scenario; however, if its use is anticipated it needs to be rehearsed as a standardised drill
  • Most of the literature on these agents pertains to well patients undergoing elective anaesthesia and we should be cautious about extrapolating results to the critical care setting
  • Finally, the urgency of a CICV can be reduced by CICVBCO – ‘can’t intubate, can’t ventilate, but CAN oxygenate’ – apnoeic diffusion oxygenation should be employed using pharyngeal or nasal oxygen10. Such a simple but underutilised technique can hugely improve the safety of RSI in critical care, and is described here.

1. Effect of suxamethonium vs rocuronium on onset of oxygen desaturation during apnoea following rapid sequence induction
Anaesthesia. 2010 Apr;65(4):358-61
2. Critical hemoglobin desaturation will occur before return to an unparalyzed state following 1 mg/kg intravenous succinylcholine.
Anesthesiology. 1997 Oct;87(4):979-8
3. Hemoglobin desaturation after succinylcholine-induced apnea: a study of the recovery of spontaneous ventilation in healthy volunteers.
Anesthesiology. 2001 May;94(5):754-9
4. Succinylcholine dosage and apnea-induced hemoglobin desaturation in patients
Anesthesiology. 2005 Jan;102(1):35-40
5. Can sugammadex save a patient in a simulated ‘cannot intubate, cannot ventilate’ situation?
Anaesthesia. 2010 Sep;65(9):936-41
6. Can sugammadex save a patient in a simulated ‘cannot intubate, cannot ventilate’ situation?
Anaesthesia. 2011 Mar;66(3):223-4
7. Unexpected failure of rocuronium-mediated neuromuscular blockade
Anaesthesia. 2011 Jan;66(1):58-9
8. Repeat dosing of rocuronium 1.2 mg kg−1 after reversal of neuromuscular block by sugammadex 4.0 mg kg−1 in anaesthetized healthy volunteers: a modelling-based pilot study
Br J Anaesth. 2010 Oct;105(4):487-92
9. Comparison of Succinylcholine and Rocuronium for First-attempt Intubation Success in the Emergency Department
Acad Emerg Med. 2011;18:11-14
10. Critical hemoglobin desaturation can be delayed by apneic diffusion oxygenation
Anesthesiology. 1999 Jan;90(1):332-3

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Neuromuscular blockade facilitates mask ventilation

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A blinded randomised controlled trial of rocuronium versus saline in anaesthetised patients demonstrated that mask ventilation was easier in paralysed patients.
The authors comment on the implications of this finding:
‘Our finding that neuromuscular blockade facilitates mask ventilation has important implications for the practice of managing difficult or impossible mask ventilation after administration of these drugs. Options in this case include returning to spontaneous ventilation, tracheal intubation, placement of a supraglottic airway device or obtaining emergency invasive airway access. In most cases, returning to spontaneous ventilation is not practical in a reasonable time frame, leaving tracheal intubation, supraglottic airway placement or emergency invasive airway access as the only feasible choices. Considerable evidence exists indicating that neuromuscular blockade facilitates tracheal intubation; and since our data further indicate that neuromuscular blockade facilitates mask ventilation, it follows that administering neuromuscular blockade is an advantage, rather than a hindrance when given early in a case of unrecognised difficult mask ventilation.‘
ABSTRACT
We wished to test the hypothesis that neuromuscular blockade facilitates mask ventilation. In order reliably and reproducibly to assess the efficiency of mask ventilation, we developed a novel grading scale (Warters scale), based on attempts to generate a standardised tidal volume. Following induction of general anaesthesia, a blinded anaesthesia provider assessed mask ventilation in 90 patients using our novel grading scale. The non-blinded anaesthesiologist then randomly administered rocuronium or normal saline. After 2 min, mask ventilation was reassessed by the blinded practitioner. Rocuronium significantly improved ventilation scores on the Warters scale (mean (SD) 2.3 (1.6) vs 1.2 (0.9), p<0.001). In a subgroup of patients with a baseline Warters scale value of >3 (i.e. difficult to mask ventilate; n=14), the ventilation scores also showed significant improvement (4.2 (1.2) vs 1.9 (1.0), p=0.0002). Saline administration had no effect on ventilation scores. Our data indicate that neuromuscular blockade facilitates mask ventilation. We discuss the implications of this finding for unexpected difficult airway management and for the practice of confirming adequate mask ventilation before the administration of neuromuscular blockade.
The effect of neuromuscular blockade on mask ventilation
Anaesthesia. 2011 Mar;66(3):163-7