Spare the Tube, Save a Life

This is part of a recurring series examining landmark articles in Emergency Medicine, in the style of ALiEM’s 52 Articles.

Discussing:

Brochard, L. Mancebo, J. Wtsocki, M. et al. “Noninvasive Ventilation for Acute Exacerbations of Chronic Obstructive Pulmonary Disease.” NEJM 1995, 333(13):817-22.

Main Points:

  1. In this randomized prospective multicenter trial of 85 patients admitted to ICUs throughout Europe with COPD exacerbations, noninvasive ventilation reduced the need for endotracheal intubation, length of stay and in-hospital mortality rate.
  1. 31 of the 42 patients in the standard arm required intubation, compared to 11 of 43 patients in the noninvasive arm (p<0.001). These results were consistent among the five centers studied. The mortality rate and length of stay was similar in the two groups in whom endotracheal intubation was required, suggesting that the benefits observed in noninvasive ventilation resulted from lower rates of intubation.
Figure 1. Mask used to deliver noninvasive ventilation

Figure 1. Mask used to deliver noninvasive ventilation

Background:

COPD exacerbations often manifest as acute hypercapnic ventilatory failure and endotracheal intubation can be a life-saving procedure. This intervention, however, is not without associated risks both during the time of the procedure as well as later in the course of the patient’s care. This patient population is at risk for hemodynamic compromise during intubation and may be difficult to manage on the ventilator due to a multitude of concerns including air trapping and tachypnea. The risk for ventilator associated pneumonia and other complications secondary to being intubated for prolonged periods of time are also worth considering.

Brochard and his colleagues investigated the use of noninvasive ventilation in COPD exacerbations in hopes of reducing mortality through the reduction of intubation. Thiswas a multicenter prospective randomized study that recruited patients in five European ICUs. The primary and secondary outcomes were patient-centered and this article from 1995 has clearly framed the manner in which we manage the sick COPD patient today. The medications used and manner in which noninvasive ventilation is employed has evolved since the publication and a comprehensive review of management was published in 2010 by the American Academy of Family Physicians. ACEP also has published clinical guidelines on use of noninvasive ventilation in 2010.

Details:

This prospective multicenter study enrolled 85 out of 275 patients admitted to the ICU with COPD or a high probability of the disease based on careful history, physical examination and chest x-ray. Patients were selected if they had a respiratory acidosis and elevated bicarbonate level. Additional criteria included dyspnea for less than two weeks and at least two of the following: respiratory rate >30 BPM, partial pressure of arterial O2 <45 mm Hg, arterial pH <7.35 after the patient was breathing room air for at least 10 minutes. The exclusion criteria included: respiratory rate <12 BPM, need for immediate intubation-defined by strict criteria in the paper, already intubated, use of sedative drugs in the past 12 hours, CNS disorder, cardiac arrest in the past five days, cardiogenic pulmonary edema, neuromuscular or skeletal disorder, upper airway obstruction or asthma, clear cause of decompensation requiring treatment, or facial deformity. Patients were either assigned to the standard arm which included treatment with: maximum of 5LPM O2 by nasal prongs with goal O2 saturation >90%, medications such as subcutaneous heparin, antibiotic agents and bronchodilators (subcutaneous terbutaline, aerosolized or intravenous albuterol, corticosteroids or intravenous aminophylline), correction of electrolytes. The noninvasive arm received the same medications with the addition of periods of noninvasive ventilation. The same apparatus was used at all five sites to deliver pressure support of 20 cm H20 with an expiratory pressure that was atmospheric. Patients underwent noninvasive ventilation for at least six hours a day with overall duration determined by clinical criteria and arterial blood gal levels.

In order to standardize care, the authors created major and minor criteria as objective markers for the need to perform endotracheal intubation. The major criteria included: respiratory arrest, respiratory failure with LOC or gasping for air, psychomotor agitation making nursing care impossible and requiring sedation, HR<50 BPM with loss of alertness, hemodynamic instability with SBP <70 mm Hg. There was a series of minor criteria also relating to vital sign instability, mental status changes or arterial pH <7.3. In both groups the presence of one major criterion was an indication for intubation. After the first hour of treatment the presence of two minor criteria was an indication for intubation.

Patients were evaluated at the one hour, three hour and 12 hour mark following the initiation of therapy. The primary outcome examined was the need for endotracheal intubation with secondary end points including length of stay, complications not present on admission (pneumonia, barotrauma, gastrointestinal hemorrhage, renal insufficiency, neurologic events and pulmonary embolism), duration of ventilatory assistance, and mortality rate during hospitalization. 31 of the 42 patients in the standard arm required intubation, compared to 11 of 43 patients in the noninvasive arm (p<0.001). Per the authors, these results were consistent among the five centers studied, however, examining table 2 sites one and two seemed to have high percentages of intubation, 100 and 83 percent respectively, compared to the others. This may be skewed by the overall low numbers studied. Patients who ultimately were intubated both in the standard and noninvasive arms had extended ventilation time with 17 +/- 21 days and 25 +/- 17 days respectively. Complications and events leading to death are shown in Table 4.

Level of Evidence:

This study was graded a level I based on the ACEP Clinical Policy Grading Scheme for therapeutic questions.

Surprises:

The use of pressure support of 20/0 is quite different from the manner in which many providers initiate noninvasive ventilation today. This may be secondary to the limitations of the technology at the time because the photograph in figure 1 (see above) displays a mask that appears different from what you find on modern machines.

Relevant articles:

Ahn, J. Pillow, T. “Focus On: Noninvasive Positive Pressure Ventilation in the Emergency Department.” 2010, http://www.acep.org/Clinical—Practice-Management/Focus-On–Noninvasive-Positive-Pressure-Ventilation-In-the-Emergency-Department/

Evensen, A. “Management of COPD Exacerbation.” Am Fam Physician 2010, 81(5): 607-13. http://www.aafp.org/afp/2010/0301/p607.html

Faculty Reviewer: Dr. Siket

Source Articles:

Brochard, L. Mancebo, J. Wtsocki, M. et al. “Noninvasive Ventilation for Acute Exacerbations of Chronic Obstructive Pulmonary Disease.” NEJM 1995, 333(13):817-22.

The Cricothyrotomy Part 3: Pediatric Points

a blog series on emergency medicine procedures

PEDIATRIC POINTS

In our last 2 posts (the cricothyrotomy part 1 and the cricothyrotomy part 2), we focused on adults. That is because the open surgical airway is often contraindicated in children as we discuss below, and there is an alternative method depending on age.

pearl12

PEARL: the cricothyroid membrane in children is significantly different…

Ped cric anat

From Roberts and Hedges’ Clinical Procedures in Emergency Medicine, 6th ed, 2013

  • Smaller
  • More anterior
  • Funnel shape
  • Structures like the larynx are more difficult to stabilize

pearl12

PEARL: in the majority of cases, open surgical cric on children is contraindicated

  • Children younger than 10-12 years old should not have an open surgical cricothyrotomy according to most emergency medicine textbooks
  • Why: risk of injuring important structures due to the anatomical differences listed above
  • Instead, if a non-invasive airway is impossible, perform a percutaneous needle cricothyrotomy

pearl12

PEARL: what type of ventilation to use

  • Bag ventilate if the patient is < 5 years old (risk of barotrauma with jet)
  • Jet ventilate if the patient is greater than 5 years old

 

SUMMARY

Child < 10-12 years old, cannot intubate, cannot ventilate, and rescue airway devices not working? Perform percutaneous needle cricothyrotomy (see below).

< 5 years old? Bag ventilate.

> 5 years old? Jet ventilate.

 

TECHNIQUE

  • Percutaneous needle puncture of the cricothyroid membrane
  • Translaryngeal ventilation (PTLV) by jet insufflation OR bag insufflation (age dependent)

This slideshow requires JavaScript.

From Roberts and Hedges’ Clinical Procedures in Emergency Medicine, 6th ed, 2013

From Beck et al, Academic Emergency Medicine, Percutaneous Transtracheal Jet Ventilation, 2011 

 

Please also view these resources from our own Brown faculty!

Dr. Valente Sim Video 

Procedurettes Junior Jet Job

 

PLEASE SHARE ANY PEDIATRIC POINTS ON THE CRICOTHYROTOMY IN THE COMMENTS SECTION! 

 

Textbook References

Hebert R, Bose S, Mace. Cricothyrotomy and Percutaneous Translaryngeal Ventilation. Chapter 6, 120-133.e2. In: Roberts J, et al. Roberts & Hedges’ Clinical Procedures in Emergency Medicine. 6th Saunders; 2013.

Smith M. Surgical Airway Management. In: Tintinalli JE, et al. Tintinalli’s Emergency Medicine. 7th ed. New York: McGraw-Hill; 2011.

Walls RM: Airway. In Marx JA, Hockberger RS, Walls RM: Rosen’s Emergency Medicine: Concepts and Clinical Practice, 6th ed, vol. 1. Philadelphia, Elsevier, 2006, pp 2-25.

Image References

Hebert R, et al. Cricothyrotomy. In: Procedures Consult. Elsevier; 2008.

Authorship

Faculty Reviewers: Gita Pensa MD and David Lindquist MD 

Author: Jonathan Ameli MD

 

The Cricothyrotomy Part 2: Pearls, Pitfalls, and Troubleshooting

a blog series on emergency medicine procedures

In the last post (the cricothyrotomy part 1) we focused on the basics of preparation and technique for the cricothyrotomy procedure. Here we focus on the pearls, pitfalls, and troubleshooting with a strong emphasis on anatomy.

As an aside…

Always consider alternatives to the cricothyrotomy, and especially, the “crash” cricothyrotomy

  • Try other non-invasive rescue maneuvers including the intubating LMA as Dr. Nestor mentioned last week

  • Review the difficult airway algorithms that were briefly acknowledged last week, and strive for expertise in airway decision-making

  • Do not hesitate to overhead anesthesia for assistance in any difficult airway

  • Avoid paralyzing patients with tenuous airways in appropriate situations, and consider awake (fiberoptic or other) intubation, or even awake cricothyrotomy with ketamine (and local anesthetic)

pearl12

PEARL #1: KNOW YOUR ANATOMY…

Why is this so important? First let’s explore some potential pitfalls….

pitfall-sign

PITFALL: You make your vertical incision OFF midline

  • You may not find the membrane
  • Complications: you may injure the following structures:
    • Cricothyroid muscles
    • Recurrent laryngeal nerves (uncommon)
    • Carotid artery / Internal Jugular vein (very rare)

pitfall-sign

PITFALL: You make a horizontal cut too SUPERIOR

  • Superior to cricothyroid membrane:
    • This is above the cords, and likely the location of your issue (i.e.: obstruction or other)
    • Complications: increased risk of vascular and nerve damage: superior laryngeal vessels and the internal branch of the superior laryngeal nerve

Continue reading

The Cricothyrotomy Part 1: The Procedure

a blog series on emergency medicine procedures

A SURGICAL AIRWAY IS IMMINENT…

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YOU CANNOT INTUBATE – CANNOT VENTILATE!

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INDICATIONS

  • Cannot intubate:
    • Multiple attempts with most experienced operator
    • Both conventional and rescue techniques attempted (1)
  • Cannot ventilate:
    • Cannot get chest rise with BVM, LMA, or other rescue devices between attempts
  • Cannot maintain O2 sat > 90%

OR

  • Extreme facial or oropharynx deformity

CONTRAINDICATIONS

  • Other airway options have not been considered
  • Pediatric patient (for open surgical method) (<10-12 years old, varies depending on expert opinion)
  • Tracheal transection, larynx or cricoid cartilage fracture, obstruction at or below the membrane

DIFFICULT AIRWAY ALGORITHMS

Watch this video to learn a simplified approach from Dr. Reuben Strayer.

From Dr. Reuben Strayer’s Advanced Airway Management for the Emergency Physician 

HUNTING & GATHERING

PROCEDURE

Continue reading

When life gives you LEMONs- Predicting difficult intubations in the ED

Article:

Reed MJ, Dunn MJ, & McKeown DW. Can an Airway Assessment Score Predict Difficulty at Intubation in the Emergency Department? Emerg Med J 2005; 22(2): 99 – 102.

Main Points:

  1. Rapid assessment tools can be helpful in predicting difficult intubations in the emergency department
  1. Use of SOME elements of the LEMON (look, evaluate, mallampati, obstruction, neck mobility) approach to airway assessment MAY be helpful in predicting likely laryngoscopic view (Cormack- Lehane grade) as a proxy for difficulty of intubation. The following are more likely found in patients with high grade views (2-4).
  • large incisors
  • reduced inter-incisor distance
  • reduced thyroid to floor of mouth distance

Background:

Predicting difficult intubations is not always straightforward. At the time of publication (2005), little validation of rapid assessment of possible difficult intubations in the ED. The authors test the use of the LEMON approach as a predictor of difficult intubations, and suggest key parts of the assessment that are most helpful.

 

Details:

The study was a prospective, observational trial conducted in the UK at a teaching Emergency Department between June 2002 and September 2003.   156/177 patients intubated over that time were included in the study. Those excluded were done so because no LEMON assessment was completed. Of the remaining included, a modified LEMON assessment was completed including: LOOK- facial trauma, large incisors, large tongue, facial hair; EVALUATE- inter-incisor distance (<3 fingers), hyoid-mental distance (<3 fingers), thyroid to floor of mouth distance (<2 fingers); MALLAMPATI 1/2 versus 3/4 ; OBSTRUCTION; and NECK MOBILITY- cervical collar versus no collar. One point was assigned for each criterion that was found. If a criterion was though unassessable, a score of zero was given. Outcome was determined by laryngoscopic view as outlined by the Cormack-Lehane grading scale; grade 1 was considered an easy intubation, grades 2-4 were considered difficult. ALL intubations were successful, and if multiple attempts were used, the grade of view on the successful attempt was used. Authors used Fischer’s exact test to compare the categorical variables, Student’s t test to compare continuous data. Spearman rank sum test was used to assess correlation between categorical variables.

Continue reading

Of course the patient’s blue…that’s why I’m intubating.

 

Discussing: “Preoxygenation, Reoxygenation, and Delayed Sequence Intubation in the Emergency Department” (Weingart SD, J Emerg Med. 2010 Apr 7)

Main Points:

  1. Patients requiring intubation should be classified by oxygenation saturation as low risk, high risk and apneic.  
  2. Reservoir face masks with oxygen set at the highest rate possible are the recommended sources of high FiO2 during preoxygenation.  
  3. All patients, if possible, should be intubated with the head-elevated position to increase safe apnea time.
  4. Consider using CPAP masks, noninvasive positive pressure ventilation or PEEP valves on a bag-valve mask in patients who cannot achieve oxygen saturations greater than 93%-95%
  5. Rocuronium may provide a longer duration of a safe apneic period in patients with a high risk of desaturation.
  6. A nasal cannula set at 15 L/minute is effective at providing oxygenation during the apneic period.

Background:

Intubation is a vital procedure to the Emergency Physician.  Yet there is more to it than just placing an endotracheal tube.  There is the setup, positioning, oxygenation, sedation, checking tube placement, and more.  On top of this, there is the underlying illness to consider.  The truth is, the majority of patients intubated in the Emergency Department (ED) are sick.  Something is very physiologically wrong, and they are not maintaining adequate oxygenation.  It becomes your job to do this for them.  The authors in this article did an extensive literature review on pre-intubation and peri-intubation techniques which reduce the risk of hypoxia in the adult patient requiring intubation in the ED.   Continue reading

ED Ventilator Settings

Quality Control editors at work.

Quality Control editors at work.

All excited for intubation but forget to optimize the ventilatory settings?

Important for those that are not rapidly taken away to the ICU.

Ventilation
Tidal Volumes: low tidal volumes 6 ml/kg (ideal body weight) even without acute lung injury is even beneficial.  Study by Determann et al. 2010 Critical Care.  Looked at 150 patients, randomized trial of 10 vs 6 ml/kg.  Development of Acute lung injury in 13.5 in the 10 ml/kg group and 2.6 in the 6 ml/kg group.  Stopped early because of difference.
Respiratory Rate: Minute ventilation is RRxTV.  You want a MV of 5-6L/min in a normal patient, but if need to increase for metabolic derrangement may need much higher.  Permissive hypercapnea is okay in those with ARDS.  Caution in those with brain injury and severe metabolic acidosis.  Don’t go higher than RR of 35.  Keep ph>7.15, as done in ARDSnet. Continue reading

Angioedema Disposition

Angioedema is anatomically limited, non-pitting edema that occurs in 10% of Americans, with men=women

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             www.flickr.com

Who should be admitted, and to where?

  • Retrospective 10 year review of 93 episodes of angioedema from Boston Medical Center
  • 39% of the cases were from ACEI, 19% from food, 11% antibiotics, 9% multiple agents, and 33% unknown cause
  • Voice change, hoarseness, stridor, SOB were associated with need for airway intervention
  • 31% of patients had facial rash, facial edema or lip edema (stage 1); 5% had soft palate edema (stage 2)
  • 32% had tongue edema (stage 3) and 31 % had laryngeal edema (stage 4)
  • Need for intervention:
    • Stage 1, facial: 0 ICU, 0 intervention
    • Stage 2, soft palate: 0 ICU, 0 intervention
    • Stage 3, lingual edema: 26% outpatient, 7% floor, 67% ICU, 7% intervention.  DIFFUSE TONGUE worse than anterior/lateral tongue.
    • Stage 4, laryngeal: 100% ICU, 24% intervention

Bottom line: ADMIT diffuse tongue and laryngeal edema, voice change, hoarseness, stridor, or SOB to the ICU due to a combined 31% incidence of airway intervention. Consider early intubation.

Ishoo E. Predicting airway risk in angioedema: Staging system based on presentation.  Head and Neck Surgery 1999.