Tag Archives: airway

All Updates, ICU, Resus

Remifentanil for awake intubation

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Awake fibreopic intubation (AFOI) is indicated in a subgroup of critically ill patients in whom RSI is contraindicated due to a predicted difficult airway, and in whom time pressures do not mandate a more immediate route to the airway. Last night I intubated a patient with a swollen tongue using this technique, under remifentanil sedation. It was interesting to subsequently see that this month’s Anaesthesia contains an article on ‘remi’ for AFOI:

Remifentanil is increasingly being used as the primary agent to provide sedation during awake fibreoptic nasal intubation. In this observational study, we aimed to determine the optimal effect site concentration of remifentanil, using a target controlled infusion based on the Minto pharmacological model, to provide optimal safe intubation conditions without the use of other sedatives/premedication and/or spray-as-you-go local anaesthesia. Twenty patients with anticipated difficult airway participated in the study. Good intubating conditions were achieved in all patients with mean (SD) effect site concentration of 6.3 (3.87) ng.ml(-1) of remifentanil recorded at nasal endoscopy and 8.06 (3.52) ng.ml(-1) during tracheal intubation. No serious adverse event occurred during any of these procedures. These preliminary findings suggest that this is a feasible and safe technique for awake fibreoptic nasal intubation.

Remifentanil as single agent to facilitate awake fibreoptic intubation in the absence of premedication
Anaesthesia. 2011 May;66(5):368-72
Those of us not familiar with target controlled infusions might find a dose in micrograms per kilo more helpful. This paper from Analgesia and Anesthesia provides a useful guide, comparing relatively high and low doses of loading and maintenance doses:

Awake nasotracheal fiberoptic intubation requires an anesthetic management that provides sufficient patient comfort, adequate intubating conditions, and stable hemodynamics. Short-acting and easily titratable analgesics are excellent choices for this maneuver. In this study, our aim was to determine an appropriate dosage regimen of remifentanil for awake nasotracheal fiberoptic intubation. For that reason, we compared two different dosage regimens. Twenty-four patients were randomly assigned to receive remifentanil 0.75 micro g/kg in bolus, followed by a continuous infusion of 0.075 micro g x kg(-1) x min(-1) (Group L), or remifentanil 1.5 micro g/kg in bolus, followed by a continuous infusion of 0.15 micro g x kg(-1) x min(-1) (Group H). All patients were premedicated with midazolam 0.05 mg/kg IV and glycopyrrolate 0.2 mg IV. Both dosage regimens ensured patient comfort and sedation. Discomfort did not differ between groups. Patients in Group H were sedated more profoundly. Hemodynamic stability was maintained with both remifentanil doses. Intubating conditions were adequate in all patients and comparable between the groups. The large dosage regimen did not result in any additional benefit compared with the small dosage. For awake nasotracheal fiberoptic intubation, we therefore recommend remifentanil 0.75 micro g/kg in bolus followed by continuous infusion of 0.075 micro g x kg(-1) x min(-1), supplemented with midazolam 0.05 mg/kg

Awake nasotracheal fiberoptic intubation: patient comfort, intubating conditions, and hemodynamic stability during conscious sedation with remifentanil
Anesth Analg. 2003 Sep;97(3):904-8 (Free Full Text)

 
An alternative to bolus + maintenance is using an incremental infusion rate via an infusion pump. In a comparision with midazolam and fentanyl, remifentanil was given to 37 patients in incremental dosages (0.1-0.25-0.5 microg/kg/min) by an infusion pump according to comfort, level of sedation and respiratory depression. Nasotracheal intubation was better tolerated in the remifentanil group, who also showed better suppression of haemodynamic effects of intubation.

BACKGROUND: Awake fiberoptic intubation is the standard of care for difficult airway management. Quality and success of this technique depend on the experience of the intubating physician and the proper preparation of the patient. The aim of this study was to compare remifentanil (R) as single agent to the combination of fentanyl (F) and midazolam (M), which have been the drugs for analgesia and sedation for this procedure.
METHODS: Seventy-four adult patients requiring nasotracheal intubation were randomly assigned to one of two groups. In group I, (n=37) R was administered in incremental dosages (0.1-0.25-0.5 microg/kg/min) by an infusion pump according to comfort, level of sedation and respiratory depression. In group II, (n=37) analgesia and sedation was achieved by F 1.5 microg/kg and doses of between 1 and 10 mg M, titrated to the individual needs. Patient reactions like grimacing, movement and coughing during intubation were assessed, as well as patient recall of the procedure. Haemodynamic and respiratory parameters were continuously recorded.
RESULTS: Group I patients better tolerated nasal tube passage (P<0.001) and laryngeal tube advancement (P<0.001) than group II. Remifentanil better suppressed hemodynamic response to nasal intubation (P<0.001). No significant difference in respiratory data was recorded. In group I more recall of the procedure was observed (six vs. zero patients, P<0.05).
CONCLUSION: Remifentanil in high doses, as the single agent for patient preparation for awake fiberoptic intubation seems to improve intubating conditions, quality and reliability of the procedure. However, a higher incidence of recall is to be expected.

Evaluation of remifentanil as single drug for awake fiberoptic intubation
Acta Anaesthesiol Scand. 2002 Apr;46(4):350-4
Some authors advocate dexmedetomidine for AFOI. Remifentanil was compared with dexmedetomidine in a randomised, double-blind trial. Remi was loaded and maintained at the ‘low’ dose as described in the second paper above and was associated with a higher intubation success rate on first attempt than dexmedetomidine (76% vs 38%):

Introduction: Dexmedetomidine (DEX), a centrally acting, selective alpha-2 agonist, with analgesic and sedation properties, has been successfully used for sedation in intensive care units. Remifentanil (REM), an ultra-short acting synthetic opioid, is often used to aid awake fiberoptic intubation (AFOI). As a narcotic, REM has a potential for respiratory depression, whereas DEX does not. This study compares the use of REM and DEX as adjuncts to local anesthetic preparation of the airway for AFOI.
Methods: Thirty adult ASA I-III patients with expected difficult airways were randomized to receive REM or DEX for sedation during AFOI. Operators and assessors were blinded to the drug used. Preoperatively, all patients received 2 mg midazolam intravenously and their airways were topicalized with 4% lidocaine. Patients in the REM group received a bolus of 0.75 mcg/kg over 10 minutes followed by an infusion of 0.075 mcg/kg/min. Patients in the DEX group received a bolus of 0.4 mcg/kg over 10 minutes followed by an infusion of 0.7 mcg/kg/hr. A word and picture set was presented to each patient before any drugs were administered, after loading of either sedative, and following extubation. Heart rate, blood pressure, respiratory rate, SpO2, bispectral (BIS) index level, and Ramsay sedation level (RSS) were recorded. Recall of each 3 sets of pictures and words was assessed at 30 minute intervals for a period of 3 hours after the completion of surgery.
Results: Patient demographics were similar between the 2 groups. All patients’ airways were successfully secured by fiberoptic intubation. Seventy-six percent of REM cases were intubated on the first attempt, as compared to 38% of the DEX cases (p=0.02). Intubation attempts were greater in the DEX group even after adjusting for confounders (OR unadjusted = 5.26, 95% C.I. = 1.19, 25.72; OR adjusted = 4.84, 3.43, 6.82). The DEX group had a higher mean oxygen saturation rate than REM (1.58 higher; 95% C.I. = 0.14, 3.03; p=0.03). Although the incidence of O2 saturation < 90% was greater in the REM group, it was not significant. No apneic episodes occurred and no rescue maneuvers, such as administration of reversal drugs or positive pressure ventilation, were required in either group. There was a lower Ramsey Sedation Scale (RSS) score (lower by = 0.45, 95% C.I. = 0.1142, 0.7792; p=0.008) in the DEX group compared to the REM group. A Kaplan Meier survival analysis showed that DEX patients took longer to attain a RSS of 3 despite reaching a lower RSS score. (Logrank test = 4.00 with one degree of freedom, p=0.0455) The DEX group also had 6.99 lower (95% C.I. = 1.19, 12.79; p=0.018) BIS score compared to the REM group. Generalized estimating equations (xtgee) showed no significance in the recall results with the exception of verbal recall in the DEX group after the initial bolus. Minimal hemodynamic instability was observed in both groups.
Discussion: Both Dex and REM can be safely used as sedative agents for AFOI. Despite increased sedation and lower recall after the initial bolus, the DEX group required more attempts at intubation. Nonetheless, lower oxygen saturation was observed in the REM group.

Dexmedetomidine vs. Remifentanil for Sedation in Awake Intubations-A Randomized, Double-Blind Trial
Anesthesiology 2008; 109 A14

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Pre-hospital Airtraq use often failed

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The Airtraq seems nifty when you try it on a manikin, but until now the question of whether it would be a useful pre-hospital tool was unanswered. This Austrian study provides helpful data:

OBJECTIVES: The optical Airtraq laryngoscope (Prodol Meditec, Vizcaya, Spain) has been shown to have advantages when compared with direct laryngoscopy in difficult airway patients. Furthermore, it has been suggested that it is easy to use and handle even for inexperienced advanced life support providers. As such, we sought to assess whether the Airtraq may be a reliable alternative to conventional intubation when used in the prehospital setting.
DESIGN, SETTING, AND PATIENTS: Prospective, randomized control trial in emergency patients requiring endotracheal intubation provided by anesthesiologists or emergency physicians responding with an emergency medical service helicopter or ground unit associated with the Department of Anesthesiology, General Hospital, Wiener Neustadt, Austria.
MEASUREMENTS AND MAIN RESULTS: During the 18-month study period, 212 patients were enrolled. When the Airtraq was used as first-line airway device (n=106) vs. direct laryngoscopy (n=106), success rate was 47% vs. 99%, respectively (p<.001). Reasons for failed Airtraq intubation were related to the fiber-optic characteristic of this device (i.e., impaired sight due to blood and vomitus, n=11) or to assumed handling problems (i.e., cuff damage, tube misplacement, or inappropriate visualization of the glottis, n=24). In 54 of 56 patients where Airtraq intubation failed, direct laryngoscopy was successful on the first attempt; in the remaining two and in one additional case of failed direct laryngoscopy, the airway was finally secured employing the Fastrach laryngeal mask. There was no correlation between success rates and body mass index, age, indication for airway management, emergency medical service unit, or experience of the physicians. CONCLUSIONS: Based on these results, the use of the Airtraq laryngoscope as a primary airway device cannot be recommended in the prehospital setting without significant clinical experience obtained in the operation room. We conclude that the clinical learning process of the Airtraq laryngoscope is much longer than reported in the anesthesia literature.

Use of the Airtraq laryngoscope for emergency intubation in the prehospital setting: A randomized control trial
Crit Care Med. 2011 Mar;39(3):489-93

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Video laryngoscope successes and failures

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With a difficult airway, video laryngoscopes can get you out of a hole – or rather into one. However they’re not guaranteed for all eventualities; a large study of Glidescope use showed:

  • Primary intubation with the Glidescope was successful in 98% of 1,755 cases and rescued failed direct laryngoscopy in 94% of 239 cases.
  • Altered neck anatomy with presence of a surgical scar, radiation changes, or mass was the strongest predictor of Glidescope failure.

 

 

INTRODUCTION: The Glidescope video laryngoscope has been shown to be a useful tool to improve laryngeal view. However, its role in the daily routine of airway management remains poorly characterized.
METHODS: This investigation evaluated the use of the Glidescope at two academic medical centers. Electronic records from 71,570 intubations were reviewed, and 2,004 cases were identified where the Glidescope was used for airway management. We analyzed the success rate of Glidescope intubation in various intubation scenarios. In addition, the incidence and character of complications associated with Glidescope use were recorded. Predictors of Glidescope intubation failure were determined using a logistic regression analysis.
RESULTS: Overall success for Glidescope intubation was 97% (1,944 of 2,004). As a primary technique, success was 98% (1,712 of 1,755), whereas success in patients with predictors of difficult direct laryngoscopy was 96% (1,377 of 1,428). Success for Glidescope intubation after failed direct laryngoscopy was 94% (224 of 239). Complications were noticed in 1% (21 of 2,004) of patients and mostly involved minor soft tissue injuries, but major complications, such as dental, pharyngeal, tracheal, or laryngeal injury, occurred in 0.3% (6 of 2,004) of patients. The strongest predictor of Glidescope failure was altered neck anatomy with presence of a surgical scar, radiation changes, or mass.
CONCLUSION: These data demonstrate a high success rate of Glidescope intubation in both primary airway management and rescue-failed direct laryngoscopy. However, Glidescope intubation is not always successful and certain predictors of failure can be identified. Providers should maintain their competency with alternate methods of intubation, especially for patients with neck pathology.

Routine Clinical Practice Effectiveness of the Glidescope in Difficult Airway Management
Anesthesiology. 2011 Jan;114(1):34-41

Acute Med, All Updates, Resus

Emergency tracheal intubations outside the OR

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Most data regarding RSI complication rates traditionally come from the operating room setting. I and my colleagues made a small attempt address this in the UK with a publication in 2004. The latest, much larger, study on the subject from Michigan shows a 10% rate of difficult intubations and a 4.2% rate of airway complications.

BACKGROUND: There are limited outcome data regarding emergent nonoperative intubation. The current study was undertaken with a large observational dataset to evaluate the incidence of difficult intubation and complication rates and to determine predictors of complications in this setting.
METHODS: Adult nonoperating room emergent intubations at our tertiary care institution from December 5, 2001 to July 6, 2009 were reviewed. Prospectively defined data points included time of day, location, attending physician presence, number of attempts, direct laryngoscopy view, adjuvant use, medications, and complications. At our institution, a senior resident with at least 24 months of anesthesia training is the first responder for all emergent airway requests. The primary outcome was a composite airway complication variable that included aspiration, esophageal intubation, dental injury, or pneumothorax.
RESULTS: A total of 3,423 emergent nonoperating room airway management cases were identified. The incidence of difficult intubation was 10.3%. Complications occurred in 4.2%: aspiration, 2.8%; esophageal intubation, 1.3%; dental injury, 0.2%; and pneumothorax, 0.1%. A bougie introducer was used in 12.4% of cases. Among 2,284 intubations performed by residents, independent predictors of the composite complication outcome were as follows: three or more intubation attempts (odds ratio, 6.7; 95% CI, 3.2-14.2), grade III or IV view (odds ratio, 1.9; 95% CI, 1.1-3.5), general care floor location (odds ratio, 1.9; 95% CI, 1.2-3.0), and emergency department location (odds ratio, 4.7; 95% CI, 1.1-20.4).
CONCLUSIONS: During emergent nonoperative intubation, specific clinical situations are associated with an increased risk of airway complication and may provide a starting point for allocation of experienced first responders.

3,423 emergency tracheal intubations at a university hospital: airway outcomes and complications.
Anesthesiology. 2011 Jan;114(1):42-8

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Anaesthesia's dirty laundry – let's all learn from it

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NAP4 is here! Is that good? Yes. Why? Because it’s the long awaited 4th National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society in the United Kingdom – a multi-phase national survey that was designed to answer the questions;

  • What types of airway device are used during anaesthesia and how often?
  • How often do major complications, leading to serious harm, occur in association with airway management in anaesthesia, in the intensive care units and in the emergency departments of the UK?
  • What is the nature of these events and what can we learn from them, in order to reduce their frequency and consequences?

The Audit identified 33 deaths and 46 cases of death or brain damage as a result of airway complications during anaesthesia, in ICU and the emergency department over a one year period in the four countries of the United Kingdom.

Some major findings include:

  • Poor planning contributed to poor airway outcomes – often a failure to plan for failure.
  • The project identified numerous cases where awake fibreoptic intubation (afoi) was indicated but was not used. A lack of suitable equipment was prevalent on ICU.
  • Problems arose when difficult intubation was managed by multiple repeat attempts at intubation.
  • Events were reported where supraglottic airway devices (SAD) were used inappropriately. Patients who were markedly obese, often managed by junior trainees, were prominent in the group of patients who sustained non-aspiration events. Numerous cases of aspiration occurred during use of a first generation SAD in patients who had multiple risk factors for aspiration and in several in whom the aspiration risk was so high that rapid sequence induction, should have been used.
  • The proportion of obese patients in case reports submitted to NAP4 was twice that in the general population
  • When rescue techniques were necessary in obese patient they failed more often than in the non-obese.

Here’s my favourite bit so far – in keeping with what the literature has already told us about this technique:

There was a high failure rate of emergency cannula cricothyroidotomy, approximately 60%. There were numerous mechanisms of failure and the root cause was not determined; equipment, training, insertion technique and ventilation technique all led to failure. In contrast a surgical technique for emergency surgical airway was almost universally successful. The technique of cannula cricothyroidotomy needs to be taught and performed to the highest standards to maximise the chances of success, but the possibility that it is intrinsically inferior to a surgical technique should also be considered. Anaesthetists should be trained to perform a surgical airway.

  • failure to correctly interpret a capnograph trace led to several oesophageal intubations going unrecognised in anaesthesia. A flat capnograph trace indicates lack of ventilation of the lungs: the tube is either not in the trachea or the airway is completely obstructed. Active efforts should be taken to positively exclude these diagnoses. This applies equally in cardiac arrest as CPR leads to an attenuated but visible expired carbon dioxide trace.
  • at least one in four major airway events reported to NAP4 was from ICU or the emergency department. The outcome of these events was more likely to lead to permanent harm or death than events in anaesthesia. Analysis of the cases identified gaps in care that included: poor identification of at-risk patients, poor or incomplete planning, inadequate provision of skilled staff and equipment to manage these events successfully, delayed recognition of events and failed rescue due to lack of or failure of interpretation of capnography. The project findings suggest avoidable deaths due to airway complications occur in ICU and the emergency department.

ICU

  • failure to use capnography in ventilated patients likely contributed to more than 70% of ICU related deaths. Increasing use of capnography on ICU is the single change with the greatest potential to prevent deaths such as those reported to NAP4.
  • Displaced tracheostomy, and to a lesser extent displaced tracheal tubes, were the greatest cause of major morbidity and mortality in ICU. Obese patients were at particular risk of such events and adverse outcome from them. All patients on ICU should have an emergency re-intubation plan.

 
ED

  • Most events in the emergency department were complications of rapid sequence induction. This was also an area of concern in ICU. RSI outside the operating theatre requires the same level of equipment and support as is needed during anaesthesia. This includes capnography and access for equipment needed to manage routine and difficult airway problems.

These are just snippets – there is much more in the report, and I’m still going through it.
The Executive Summary and all other Sections of NAP4 can be downloaded here from the Royal College of Anaesthetists
 

All Updates, ICU, Resus

Longer apnoea time with roc in the obese too

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Suxamethonium increases muscle oxygen consumption as a result of skeletal muscle fasciculation. In a comparison between sux and rocuronium in rapid sequence intubation, this resulted in faster desaturation in the sux group. A further study demonstrates a similar finding in obese patients.

BACKGROUND: Rapid sequence induction may be associated with hypoxemia. The purpose of this study was to investigate the possible difference in desaturation during rapid sequence induction in overweight patients using either succinylcholine or rocuronium.
METHODS: Sixty patients with a body mass index (BMI) between 25 and 30 kg/m², American Society of Anesthesiologists class I or II, undergoing general anesthesia were randomly divided into a succinylcholine group and a rocuronium group. After a 3-min preoxygenation, patients received rapid sequence induction of general anesthesia with midazolum-fentanyl-propofol and succinylcholine (1.5 mg/kg) or rocuronium (0.9 mg/kg). Ventilation was not initiated until oxygen saturation declined to 92%. We measured the times when oxygen saturation reached 98%, 96%, 94% and 92%. Safe Apnea Time was defined as the time from administration of neuromuscular blocking drugs to oxygen saturation fell to 92%. The recovery period was defined as the time from initiation of ventilation until oxygen saturation was 97%. Arterial blood gases were taken at baseline, after preoxygenation and at 92% oxygen saturation.
RESULTS: The mean Safe Apnea Time (95% CI) was 283 (257-309) s in succinylcholine vs. 329 (303-356) s in rocuronium (P=0.01). The mean recovery period (95% CI) was 43 (39-48) s in succinylcholine vs. 36 (33-38) s in rocuronium (P=0.002). Blood gas analysis showed no difference between the two groups.
CONCLUSIONS: Succinylcholine was associated with a significantly more rapid desaturation and longer recovery of oxygen saturation than rocuronium during rapid sequence induction in overweight patients.

Desaturation following rapid sequence induction using succinylcholine vs. rocuronium in overweight patients
Acta Anaesthesiol Scand. 2011 Feb;55(2):203-8

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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

All Updates, ICU, Kids, Resus, Ultrasound

Kids tracheal tubes – formulas galore

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An ultrasound study of paediatric airways showed sonographic measurement to be a better predictor of tracheal tube size (using a formula – derived and then validated – to estimate external tube diameter) than traditional formulae for selecting the internal tube diameter based on age. Since the measurements, taken at the lower edge of the cricoid cartilage, were made after patients were paralyzed, and were performed without ventilation or positive end-expiratory pressure to minimize fluctuation in tracheal diameter, taking about 30 seconds, this is not something I anticipate applying in critical care practice. However, the paper does provide a good opportunity to revise some of the existing formulae. They used:
(1) The Cole formula for uncuffed tubes: ID (intenal diameter) in mm= (age in years)/4 + 4
(2) The Motoyama formula for cuffed ETTs in children aged 2 yr or older: ID in mm = (age in years)/4 + 3.5
(3) The Khine formula for cuffed ETTs in children younger than 2 yr: ID in mm = (age in years)/4 + 3.0
The formula established in the study was:

  • cuffed ETT outer diameter (OD) = 0.46 x (subglottic diameter) + 1.56

  • uncuffed ETT OD = 0.55 x (subglottic diameter) + 1.16

Age in months also correlated with optimal ETT size in mm, although the correlation was weaker than for subglottic diameter:

  • cuffed ETT OD = 0.027 x (age) + 5.2

  • uncuffed ETT OD = 0.030 x (age) + 5.4

BACKGROUND: Formulas based on age and height often fail to reliably predict the proper endotracheal tube (ETT) size in pediatric patients. We, thus, tested the hypothesis that subglottic diameter, as determined by ultrasonography, better predicts optimal ETT size than existing methods.
METHODS: A total of 192 patients, aged 1 month to 6 yr, who were scheduled for surgery and undergoing general anesthesia were enrolled and divided into development and validation phases. In the development group, the optimal ETT size was selected according to standard age-based formulas for cuffed and uncuffed tubes. Tubes were replaced as necessary until a good clinical fit was obtained. Via ultrasonography, the subglottic upper airway diameter was determined before tracheal intubation. We constructed a regression equation between the subglottic upper airway diameter and the outer diameter of the ETT finally selected. In the validation group, ETT size was selected after ultrasonography using this regression equation. The primary outcome was the fraction of initial cuffed and uncuffed tube sizes, as selected through the regression formula, that proved clinically optimal.
RESULTS: Subglottic upper airway diameter was highly correlated with outer ETT diameter deemed optimal on clinical grounds. The rate of agreement between the predicted ETT size based on ultrasonic measurement and the final ETT size selected clinically was 98% for cuffed ETTs and 96% for uncuffed ETTs.
CONCLUSIONS: Measuring subglottic airway diameter with ultrasonography facilitates the selection of appropriately sized ETTs in pediatric patients. This selection method better predicted optimal outer ETT diameter than standard age- and height-based formulas.

Prediction of Pediatric Endotracheal Tube Size by Ultrasonography
Anesthesiology. 2010 Oct;113(4):819-24

All Updates, ICU, Kids, PHARM, Resus, Trauma

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