Is First Pass Success an important outcome in PHEA research?

A lot of airway papers seem to use first pass success (FPS) as a marker of success. I’m a little sceptical of this as the usual definition (a single attempt at laryngoscopy and intubation) is a little limited and does not really affect the whole patient experience. As an example in the DEVICE trial, which looked at Video Laryngoscopy vs. Direct Laryngoscopy in emergency department practice, first pass success was the principal outcome measure. A review of papers looking at first pass success suggested an average of 85.1% as a benchmark, although that seems a little low to me.

This week we review a paper that questions whether first pass success is really associated with adverse outcomes in patients intubated in the prehospital setting. The abstract is shown below, but as always please read the full paper yourself.

Abstract – Does first pass success matter?

Background: Lower intubation first-pass success (FPS) rate is associated with physiological deterioration, and first-pass success is widely used as a quality indicator of the airway management of a critically ill patient. However, data on first-pass success’ association with survival is limited. We aimed to investigate if the first-pass success rate is associated with 30-day mortality or physiological complications in a pre-hospital setting. Furthermore, we wanted to describe the first-pass success rate in Finnish helicopter emergency medical services.
Methods: This was a retrospective observational study. Data on drug-facilitated intubation attempts by helicopter emergency medical services were gathered from a national database and analysed. Multivariate logistic regression, including known prognostic factors, was performed to assess the association between first-pass success and 30-day mortality, col- lected from population registry data.
Results: Of 4496 intubation attempts, 4082 (91%) succeeded on the first attempt. The mortality rates in first-pass success and non- first-pass success patients were 34% and 38% (P=0.21), respectively. The adjusted odds ratio of first-pass success for 30-day mortality was 0.88 (95% CI 0.66-1.16). Hypoxia after intubation and at the time of handover was more frequent in the non-first-pass success group (12% vs. 5%, P<0.001, and 5% vs. 3%, P=0.01, respectively), but no significant differences were observed regarding other complications.
Conclusion: First-pass successis not associated with 30-day mortality in pre-hospital critical care delivered by advanced provid- ers. It should therefore be seen more as a process quality indicator instead of a risk factor of poor outcome, at least considering the current limitations of the parameter.

Ljungqvist, J., Nilsson, M., & Nordberg, M. (2022). Intubation first-pass success in a high performing pre-hospital critical care system is not associated with 30-day mortality: a registry study of 4496 intubation attempts. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 30(1), 49. https://doi.org/10.1186/s13049-022-01049-z

What kind of paper is this?

This is a retrospective observational study. The study explores the relationship between first-pass success (FPS) during pre-hospital intubation and 30-day mortality rates in patients treated by the Finnish Helicopter Emergency Medical Services (HEMS). The study leverages a comprehensive national quality database and adds valuable insights into the efficacy and outcomes of pre-hospital airway management practices.

Retrospective observational designs are, unfortunately, prone to bias. Firstly, they can’t prove cause and effect, only suggest links since they look at past data. Selection bias may occur where the included patients might not represent the larger population due to selective record-keeping, but that is less likely to be an issue in studies like this with what looks like a pretty comprehensive database. Data quality can be problematic as it relies on what was recorded then, which may not be exactly what we are looking at here. The main problem is often that unmeasured factors can skew the results. Unlike prospective studies, controlling how data was originally collected is impossible. As a result, these studies are often hypothesis-generating rather than definitive in their own right.

These studies can challenge established dogma, and if the database is comprehensive and well-managed, they can give insight into some conditions. This study’s design is appropriate as there is no real prospective trial alternative. It is the association between FPS and mortality that is being examined, and an observational trial can answer that question.

Tell me about the patients

The study encompasses 4496 patients who underwent drug-facilitated intubation attempts by HEMS teams across Finland from January 2014 to August 2019. The median age of the patients was 59 years, with a male predominance of 65%. These patients presented with a variety of medical conditions necessitating intubation, including neurological emergencies, out-of-hospital cardiac arrests (OHCA), trauma, intoxications, and other critical conditions.

Patients were grouped based on their underlying medical conditions:

• Neurological emergencies: Included conditions such as stroke, seizures, and other acute neurological impairments.
• OHCA: Patients who suffered cardiac arrest outside the hospital setting and required immediate advanced life support.
• Trauma: Individuals with severe injuries from accidents or violence.
• Intoxication: Patients suffering from drug overdoses or poisoning.
• Others: Included miscellaneous critical conditions that required immediate airway management.

What did they do?

The study used a retrospective observational design, analyzing data from the national HEMS quality database supplemented with survival data from the National Population Registry. The primary focus was on the association between FPS during intubation and 30-day mortality while also examining secondary outcomes like hypoxia and hypotension during and after the intubation process.

Key aspects of the methodology include:

• Data Collection: Comprehensive data on patient demographics, clinical conditions, vital signs, intubation details, and subsequent outcomes were collected and analyzed.
• First-Pass Success (FPS): Defined as the successful placement of the endotracheal tube on the first attempt without the need for additional attempts.
• Outcome Measures: The primary outcome was 30-day mortality. Secondary outcomes included incidence of hypoxia (oxygen saturation <90%) and hypotension (systolic blood pressure <90 mmHg) immediately after intubation and upon handover to the hospital.
• Statistical Analysis: Multivariate logistic regression was used to adjust for potential confounders such as age, sex, Glasgow Coma Score (GCS), initial vital signs, and underlying medical conditions.

Tell me about the outcomes

The primary outcome was 30-day mortality. This was 34% across the cohort. Notably, there was no significant difference in mortality between the FPS group (34%) and the non-FPS group (38%). This suggests that while achieving first pass success is crucial for immediate airway management, it does not independently impact long-term survival.

• First-Pass Success Rate: The overall first pass success rate was high, at 91%. This indicates a proficient level of skill and effectiveness among the HEMS teams in performing intubations in a pre-hospital setting.
• Hypoxia and Hypotension: Patients in the non-first pass success group experienced higher rates of hypoxia immediately after intubation and at hospital handover. However, other complications, such as hypotension, did not show significant differences between first-pass success and non-first-pass success groups.

The key finding is the lack of association between first-pass success and 30-day mortality. This challenges the assumption that first-pass success directly indicates improved survival. The elevated hypoxia rates in the non-FPS group highlight the potential immediate risks of multiple intubation attempts but do not translate into a higher long-term mortality rate.

What do the findings mean for future research?

In a high performing service this does question whether we should solely be using FPS as an outcome in airway research.

• Reevaluating Quality Indicators: While first-pass success remains a valuable process quality indicator, this study suggests that it should not be the sole metric for evaluating the success of pre-hospital intubations. Future research should explore additional indicators that more accurately predict long-term outcomes.
• Training and Protocol Development: Given the high first-pass success rates but lack of impact on 30-day mortality, we should look again at how we train for and apply decision-making processes in emergency airway care. This might include evaluating different team compositions, training programs, and advanced/alternative airway equipment availability and how they affect PHEA and patient outcomes.
• Long-Term Outcomes: Further studies should focus on the long-term health and quality of life of patients who undergo pre-hospital intubation. Understanding the factors that influence recovery and survival beyond the initial 30 days can provide deeper insights into the effectiveness of pre-hospital interventions. Whilst first-pass success will probably always be of interest we need to understand, measure and evaluate a lot more about the practice of PHEA and not just reduce ‘success’ to FPS rates. This also applies to in-hospital practice in emergency care,.

Any implications for clinical practice?

I’ve long argued that other factors such as complications (hypoxia, hypotension, cardiac arrest etc.) are more important. I’m also worried that in systems that value first pass success above all else it may skew practice. Let’s take a scenario where the clinical application of first-pass success as a marker of success might actually cause harm.

• A pre-hospital team are performing an RSI on a 65-year-old patient. They elect to follow their standard approach and set up accordingly.
• They proceed with the RSI using a MAC3 direct laryngoscope. At first glance, they struggle to engage the vallecula as the blade is too short for this patient.
• The operator is faced with two options.
  • Change the blade to a MAC 4 or video laryngoscopy
  • Persist with the smaller blade.
• The complicating factor is that this particular operator has a known FPS rate of 92% in the service. They know that if they ‘fail’ (sic) this one they will drop below 90 for the last 6 months and therefore trigger a review.
• They make the wrong decision to persist with the MAC 3 during which time the patient becomes briefly hypoxic. (but their first pass success rate is now higher than at the beginning of the day, and they avoid an automatic review at M&M).

Now the example above is made up, but there is lots of evidence that targets drive practice. I am also glad that in Virchester Air Ambulance we do not use first pass success as a sole marker of success!! So next time someone tells you that they have a 100% first-pass success rate, maybe that’s not something to be proud of?

Final thoughts

Pre-hospital emergency anaesthesia is complex, difficult and risky. It probably makes a difference to patient outcome if it’s done well/badly, but what ‘good’ looks like is yet to be perfectly determined. That said, the key caveat in this paper is that it is a high-performing system with a high baseline first-pass success rate. There are many papers out there that define a ‘good’ first pass success rate as much lower than this. That probably means that there are other issues in those systems that extend beyond the simple passing of a tube into the trachea. So first-pass success needs not be abandoned for all services/systems; it needs to be taken into context.

References

1. Ljungqvist, J., Nilsson, M., & Nordberg, M. (2022). Intubation first-pass success in a high performing pre-hospital critical care system is not associated with 30-day mortality: a registry study of 4496 intubation attempts. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 30(1), 49. https://doi.org/10.1186/s13049-022-01049-z
2. Nolan, J. P., & Soar, J. (2008). Airway management in adults after cardiac arrest: consensus recommendations of the European Resuscitation Council. Resuscitation, 78(1), 11-16. https://doi.org/10.1016/j.resuscitation.2008.02.024
3. Wang, H. E., Simeone, S. J., Weaver, M. D., & Callaway, C. W. (2009). Interruptions in cardiopulmonary resuscitation from paramedic endotracheal intubation. Annals of Emergency Medicine, 54(5), 645-652. https://doi.org/10.1016/j.annemergmed.2009.05.026
4. Benger, J. R., Kirby, K., Black, S., Brett, S. J., Clout, M., Lazaroo, M. J., … & Nolan, J. P. (2018). Effect of a strategy of a supraglottic airway device versus tracheal intubation during out-of-hospital cardiac arrest on functional outcome: the AIRWAYS-2 randomised clinical trial. JAMA, 320(8), 779-791. https://doi.org/10.1001/jama.2018.11597
5. Mann, C. J. (2003). Observational research methods. Research design II: cohort, cross sectional, and case-control studies. Emergency Medicine Journal, 20(1), 54-60. https://doi.org/10.1136/emj.20.1.54
6. Laura Howard, “JC – Video vs Direct Laryngoscopy for Tracheal Intubation of Critically Ill Adults,” in St.Emlyn’s, June 25, 2023, https://www.stemlynsblog.org/jc-video-vs-direct-laryngoscopy-for-tracheal-intubation-of-critically-ill-adults/.
7. Video versus Direct Laryngoscopy for Tracheal Intubation of Critically Ill Adults (The DEVICE Trial). N Engl J Med 2023;389:418-29. DOI: 10.1056/NEJMoa2301601
8. Park L, Zeng I, Brainard A. Systematic review and meta-analysis of first-pass success rates in emergency department intubation: Creating a benchmark for emergency airway care. Emerg Med Australas EMA. 2017 Feb 1;29(1):40–7.