Airway Management

Topic 1 - Summary
1. Citation:

Weingart SD, Trueger NS, Wong N, Scofi J, Singh N, Rudolph SS. Delayed

sequence intubation: a prospective observational study. Ann Emerg Med. 2015

Apr;65(4):349-55

2. Summary/Bottom Lines:

This is a prospective observational study about the effectiveness of “delayed-sequence intubation” (DSI) when used on patients who do not tolerate traditional methods of preoxygenation prior to intubation. The study shows that DSI can be an effective method of treating patients who are intolerant of nonrebreather(NRB) masks or noninvasive positive pressure ventilation (NIPPV) by using ketamine to dissociate the patient. Ketamine preserves airway reflexes and prevents the patient from removing the NRB mask or NIPPV mask. Dissociating the patient while continuing efforts to preoxygenate and denitrogenate the patient improves oxygen saturation prior to the intubation attempt, giving the physician more time to intubate the patient with lower likelihood of oxygen desaturation.

3. Methods:

The study was conducted at three large hospitals - two in the United States and one in Denmark. The authors used a “convenience sample” of 62 patients at the study centers, meaning that the study investigators were free to choose which patients would be most appropriate for the study. If a patient was intolerant of efforts to preoxygenate them prior to intubation (tearing off their mask, getting out of bed, verbally stating that they couldn’t tolerate the mask), investigators tried to reassure the patients verbally and/or assist the patients by holding the mask in place. If the patient still was not tolerant of preoxygenation after a few attempts, the investigators could choose to proceed to DSI and include the patient in the study. The patient’s oxygen saturation was recorded at this point for later comparison. DSI was performed by giving the patient 1mg/kg ketamine and giving additional 0.5mg/kg doses until dissociation was achieved. Some patients were then treated with NIPPV, and some with a nonrebreather mask. Preoxygenation and denitrogenation proceeded for 3 minutes and the patient’s oxygen saturation was recorded again. At that point the investigator could choose to proceed with intubation by administration of a paralytic (rocuronium or succinylcholine), use of apneic oxygenation with a nasal cannula, then endotracheal intubation. They collected data from 64 patients undergoing DSI, primary outcome was oxygen saturation change after DSI. The mean pre-DSI saturation was 89.9%, and mean post-DSI saturation was 98.8%. The also had two patients, both asthmatics, who did not require intubation after performing oxygenation with DSI. They were able to successfully place four nasogastric tubes in patients during their DSI for heavy GI bleeding. They recorded no adverse events such as deaths, emesis, or emergence phenomenon.

4. Limits:

The study was not random - investigators chose who was entered into the study (convenience sampling) which predisposes the study to heavy selection bias. They also note that the study outcome does not include any long-term outcomes such as long term mortality, length of hospital stay, etc. This study does not include children. Despite these limitations the study does show a reasonable correlation between increased oxygen saturation prior to intubation using DSI with few short- term adverse events.

5. Additional Info:
  • Seven of the patients included in the study were being treated for asthma. Ketamine has been shown to have bronchodilatory effects, so it is not clear whether their improvement was due to the bronchodilatory effects of ketamine, or the prolonged preoxygenation which was facilitated by dissociation caused by ketamine.
  • Two were included because of ventilatory failure, but measurements of end-tidal CO2 or ABGs were not included in the study. It isn’t clear whether they also had low CO2 or were simply included due to suspected high CO2.
  • Attempts to aid the patients in tolerating NIPPV or NRB mask seemed limited to verbal reassurance or holding a mask in place. They do not mention any effort to change the modality of oxygenation - whether it be a nasal mask for NIPPV or high-flow nasal cannula, or other methods - in order to avoid intubation.
  • The study was not powered or designed to show long-term benefit to patients, but gives confidence to those including DSI into their practice by showing that it is a reasonably safe technique and may provide benefit to the patient in respiratory distress.
6. Author: Dr. Scott Barnes

 

Topic 2 - Summary
1. Citation:

Brown CA, 3rd, Bair AE, Pallin DJ, Walls RM, Investigators NI. Techniques, success, and adverse events of emergency department adult intubations. Ann Emerg Med. 2015;65(4):363–70.

2. Summary/Bottom Lines:

This study looks at trends in the practice and performance of ED intubations over 10 years. It is a descriptive, large scale, prospective, multicenter, multi-national, self- reported registry. The information was gathered by participating EDs, which were mostly academic (12/13). The intubations all took place in the ED, those reported were limited to physicians but not necessarily ED physicians. This observational study collected data between 2002 and 2012 at 13 different sites looking at various aspects of ED intubations. The reported data included: adverse events, and indications, first pass success rate of various operators (resident year, attending, anesthesiologist), preferred induction and paralytic agents, method (orotracheal, nasotracheal), and device (VL, DL, cricothyrotomy, etc). The importance of this study is that there are no other large scale studies like it; only small, short term studies in the past.

3. Methods:

Data collected by the NEAR registry. There were originally 18 centers, but 5 were removed from the study due to not meeting the >90% compliance. The 90% compliance was confirmed by comparing the number to the intubation procedures coded for by the institution and cross checked by a compliance officer. Data from 17, 583 intubations were analyzed. The criteria for the procedure to be included in the study was any adult (15+ years) ED patient with an attempt at intubation (blade past the alveolar ridge) by a physician between 7/1/2002- 12/31/2012. Data collected by the registry included patient demographics, indication for intubation, methods and device used (per each attempt), medications administered, number of attempts, success/failure, operator characteristics, intubation events, adverse events. Data was reviewed and duplicate entries removed, solitary incomplete entries were rectified by manual chart review. Incomplete entries, that could not be completed by manual chart review, were kept in the data base. The data is presented as univariate descriptive data. Trends over time were analyzed with linear or logistic regression with year as the independent variable (although the paper says year is the dependent variable).

4. Limits:
  • Self Reporting Bias
  • Recall Bias
  • Selective Reporting
  • Intracranial Hemorrhage data reporting most likely not accurate since often unknown before intubation (altered patient), so data from the medical vs trauma reasons are mixed
  • Balancing information vs compliance. More information ask for, less likelihood of maintaining 90% compliance
  • Curved vs Straight blade for DL was not differentiated as well as different blades of

Glidescopes

  • 13/14 Centers enrolled in study were Trauma 1 Academic centers with an EM Residency
  • A few of the institutions had much higher volume and acuity than others as well as some centers being in the study longer than others, and so the data is skewed towards those centers simply by numbers of data entries.
  • Because this study was observational and was a univariate analysis, there was no way to control for confounders like operator experience, Airway difficulty, etc
5. Additional Info:
  • Great study, most of the limitations in NEAR2 are being corrected in NEAR3.
  • Great foundation to determine trends in ED Intubations and great baseline to compare for future (12% adverse event rate)
6. Author: Drs. Ashley Venegas and Michael Khafi