Airway Management of Respiratory Failure

Pharmacotherapy optimization for rapid sequence intubation in the emergency department

PURPOSE

Rapid-sequence intubation (RSI) is the process of administering a sedative and neuromuscular blocking agent (NMBA) in rapid succession to facilitate endotracheal intubation. It is the most common and preferred method for intubation of patients presenting to the emergency department (ED). The selection and use of medications to facilitate RSI is critical for success. The purpose of this review is to describe pharmacotherapies used during the RSI process, discuss current clinical controversies in RSI medication selection, and review pharmacotherapy considerations for alternative intubation methods.

SUMMARY

There are several steps to the intubation process requiring medication considerations, including pretreatment, induction, paralysis, and post-intubation sedation and analgesia. Pretreatment medications include atropine, lidocaine, and fentanyl; but use of these agents in clinical practice has fallen out of favor as there is limited evidence for their use outside of select clinical scenarios. There are several options for induction agents, though etomidate and ketamine are the most used due to their more favorable hemodynamic profiles. Currently there is retrospective evidence that etomidate may produce less hypotension than ketamine in patients presenting with shock or sepsis. Succinylcholine and rocuronium are the preferred neuromuscular blocking agents, and the literature suggests minimal differences between succinylcholine and high dose rocuronium in first-pass success rates. Selection between the two is based on patient specific factors, half-life and adverse effect profiles. Finally, medication-assisted preoxygenation and awake intubation are less common methods for intubation in the ED but require different considerations for medication use.

AREAS FOR FUTURE RESEARCH

The optimal selection, dosing, and administration of RSI medications is complicated, and further research is needed in several areas. Additional prospective studies are needed to determine optimal induction agent selection and dosing in patients presenting with shock or sepsis. Controversy exists over optimal medication administration order (paralytic first vs induction first) and medication dosing in obese patients, but there is insufficient evidence to significantly alter current practices regarding medication dosing and administration. Further research examining awareness with paralysis during RSI is needed before definitive and widespread practice changes to medication use during RSI can be made.

The Impact of Do-Not-Resuscitate Order in the Emergency Department on Respiratory Failure after ICU Admission

(1) Background: It has been hypothesized that a discrepancy exists in the understanding of a do-not-resuscitate (DNR) order among physicians. We hypothesized that a DNR order signed in the emergency department (ED) could influence the patients’ prognosis after intensive care unit (ICU) admission. (2) Methods: We included patients older than 17 years, who visited the emergency department for non-traumatic disease, who had respiratory failure, required ventilator support, and were admitted to the ICU between January 2010 and December 2016. The associations between DNR and mortality, hospital length of stay (LOS), and medical fees were analyzed. Prolonged hospital LOS was defined as hospital stay ≥75th percentile (≥26 days for the study). Patients were classified as those who did and did not sign a DNR order. A 1:4 propensity score matching was conducted for demographics, comorbidities, and etiology. (3) Results: The study enrolled a total of 1510 patients who signed a DNR and 6040 patients who did not sign a DNR. The 30-day mortality rates were 47.4% and 28.0% among patients who did and did not sign a DNR, respectively. A DNR order was associated with mortality after adjusting for confounding factors (hazard ratio, 1.9; confidence interval, 1.70−2.03). It was also a risk factor for prolonged hospital LOS in survivors (odds ratio, 1.2; confidence interval, 1.02−1.44). Survivors who signed a DNR order were charged higher medical fees than those who did not sign a DNR (217,159 vs. 245,795 New Taiwan Dollars, p < 0.001). (4) Conclusions: Signing a DNR order in the ED increased the ICU mortality rate among patients who had respiratory failure and needed ventilator support. It increased the risk of prolonged hospital LOS among survivors. Finally, signing a DNR order was associated with high medical fees among survivors.

Doxycycline-Eluting Core-Shell Type Nanofiber-Covered Trachea Stent for Inhibition of Cellular Metalloproteinase and Its Related Fibrotic Stenosis

In this study, we fabricated a doxycycline (doxy)-eluting nanofiber-covered endotracheal stent for the prevention of stent intubation-related tissue fibrosis and re-stenosis. The nanofiber was deposited directly on the outer surface of the stent using a coaxial electrospinning method to form a doxy-eluting cover sleeve. Poly(d,l-lactide) was used as the shell-forming polymer and dedicated drug release-control membrane. Polyurethane was selected as the drug-loading core polymer. The compositional ratio of the core to shell was adjusted to 1:0, 1:2, and 1:4 by changing the electro-spray rate of each polymeric solution and microscopic observation of nanofibers using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the fluorescence microscopy proved core-shell structure of nanofibers. The in vitro release study suggested that the release of doxy could be controlled by increasing the compositional ratio of the shell. The growth of HT1080 fibrosarcoma cells was inhibited by the 10% doxy-containing nanofiber. The real-time polymerase chain reaction (PCR) in HT1080 cells and xenografted tissue models indicated that the doxy-releasing nanofiber inhibited mRNA expression of metalloproteinases (MT1-MMP, MMP-2, and MMP-9). Overall, our study demonstrates that a doxy-eluting core-shell nanofiber stent can be successfully fabricated using coaxial electrospinning and displays the potential to prevent fibrotic re-stenosis, which is the most problematic clinical complication of tracheal stent intubation.

Association of fentanyl use in rapid sequence intubation with post-intubation hypotension

BACKGROUND

The anesthesia literature has reported that pre-intubation fentanyl use is associated with post-intubation hypotension which is a risk factor of poor post-emergency department (ED) prognosis. However, little is known about the relations between fentanyl use for intubation and post-intubation hypotension in the ED. We aimed to determine whether pretreatment with fentanyl was associated with a higher risk of post-intubation hypotension in the ED.

METHODS

We conducted a secondary analysis of data of ED airway management collected from a multicenter prospective study of 14 Japanese EDs from February 2012 through November 2016. We included all adult non-cardiac-arrest patients who underwent rapid sequence intubation for medical indication. Patients were divided into fentanyl and non-fentanyl groups. The primary outcome was post-intubation hypotension (systolic blood pressure ≤90mmHg) in the ED.

RESULTS

Of 1263 eligible patients, 466 (37%) patients underwent pretreatment with fentanyl. The fentanyl group had a higher risk of post-intubation hypotension (17% vs. 6%; unadjusted OR, 1.73; 95%CI, 1.01-2.97; P=0.048) compared to the non-fentanyl group. In the multivariable analysis adjusting for age, sex, weight, principal indication, sedatives, intubator's specialty, number of intubation attempts, and patient clustering within EDs, the fentanyl group had a higher risk of post-intubation hypotension (adjusted OR, 1.87; 95%CI, 1.05-3.34; P=0.03) compared to the non-fentanyl group. In the sensitivity analysis using propensity score matching, this association remained significant (OR, 3.17; 95%CI, 1.96-5.14; P<0.01).

CONCLUSION

In this prospective multicenter study of ED airway management, pretreatment with fentanyl in rapid sequence intubation was associated with higher risks of post-intubation hypotension.

Editor's Choice-The cardiovascular implications of sedatives in the cardiac intensive care unit

Patients admitted to the cardiac intensive care unit frequently develop multi-organ system dysfunction associated with their cardiac disease. In many cases, invasive mechanical ventilation is required, which often necessitates sedation for patient-ventilator synchrony, reduction of work of breathing, and patient comfort. In this paper, we describe the use of common sedatives available in the endotracheally intubated critically ill patient and emphasize the clinical and cardiovascular effects. We review γ-aminobutyric acid agonists such as etomidate, benzodiazepines, and propofol, the centrally acting α₂-agonist dexmedetomidine, and the N-methyl-D-aspartate receptor antagonist ketamine. Additionally, we outline the use of opioids and their role in potentiating other sedatives. We note that some sedatives are associated with increased delirium rates, and emphasize that judicious strategies minimizing sedative use are associated with decreases in morbidity and mortality. We also discuss standardized sedation assessment scales and highlight the importance of sedation weaning. Finally, we offer recommendations for sedation use during therapeutic hypothermia, and discuss the use of adjuvant neuromuscular blocking agents.

Ability of paramedics to perform endotracheal intubation during continuous chest compressions: a randomized cadaver study comparing Pentax AWS and Macintosh laryngoscopes

OBJECTIVE

The aim of the trial was to compare the time parameters for intubation with the use of the Macintosh (MAC) laryngoscope and Pentax AWS-S100 videolaryngoscope (AWS; Pentax Corporation, Tokyo, Japan) with and without chest compression (CC) by paramedics during simulated cardiopulmonary resuscitation in a cadaver model.

METHODS

This was a randomized crossover cadaver trial. Thirty-five paramedics with no experience in videolaryngoscopy participated in the study. They performed intubation in two emergency scenarios: scenario A, normal airway without CC; scenario B, normal airway with continuous CC.

RESULTS

The median time to first ventilation with the use of the AWS and the MAC was similar in scenario A: 25 (IQR, 22-27) seconds vs. 24 (IQR, 22.5-26) seconds (P=.072). A statistically significant difference in TTFV between AWS and MAC was noticed in scenario B (P=.011). In scenario A, the first endotracheal intubation (ETI) attempt success rate was achieved in 97.1% with AWS compared with 94.3% with MAC (P=.43). In scenario B, the success rate after the first ETI attempt with the use of the different intubation methods varied and amounted to 88.6% vs. 77.1% for AWS and MAC, respectively (P=.002).

CONCLUSIONS

The Pentax AWS offered a superior glottic view as compared with the MAC laryngoscope, which was associated with a higher intubation rate and a shorter intubation time during an uninterrupted CC scenario. However, in the scenario without CC, the results for AWS and MAC were comparable.