Airway management and endotracheal intubation by paramedics for cardiac arrest

Paramedics and ETI

Paramedics are trained in airway management, including in the skill of endotracheal intubation (ETI) in practice. Guidance is available to support paramedics regarding when and how ETI should be performed, as well as local standard operating procedures (SoPs) in deploying the skill (Brown et al, 2016). Airway management takes a step-wise approach (Figure 1) and incorporates the use of supraglottic airway devices (SGAs) such as laryngeal mask airways (LMAs) and iGels. There have been several studies comparing the use of SGAs to endotracheal tubes (ETTs), including the large Airways-2 trial (Taylor et al, 2016), which has recently finished collecting data.

There are also numerous ongoing debates around paramedics performing ETI in practice; in particular, surrounding training requirements and skill degradation. A recent consensus statement from the College of Paramedics (CoP) indicates that ambulance services should provide comprehensive standardised training and paramedics should be assessed for competence in terms of skill retention (CoP, 2017). The CoP (2017) also suggests that services should have a small group of highly trained paramedics, who should be targeted to incidents appropriately. This would increase exposure to incidents requiring more advanced airway management, thus assisting with skill retention. This notion of targeted deployment has previously been unsuccessful in some areas of the UK—for instance, with the dispatch of emergency care paramedics (ECPs) to meet target response times rather than targeted to clinical requirements. It is likely that all ambulance personnel will respond to cardiac arrests, whereby airway management techniques will be required.

Equipment for ETI

ETI is an effective method to secure the airway and is historically carried out using mackintosh (curved blade) or miller (straight blade) rigid laryngoscopes (Foregger, 1966). Other devices include the McCoy blade, which has an articulating tip, and there are enhanced assisted intubation devices such as video and fibreoptic laryngoscopy, used in the hospital environment.

Performing intubation requires the preparation of the necessary equipment; opening the airway with manual manoeuvres and simple adjuncts; then pre-oxygenating the patient as effectively as possible. Equipment should be prepared and ready, including suction, before positioning the patient's head into the levitan position (Figure 2). The SOAP-ME is a useful pneumonic for ETI preparation (Figure 3). A laryngoscope is used to visualise the vocal cords, then a gum-elastic bougie (GEB) is inserted into the trachea through the vocal cords. The ETT (Figure 4) is applied over the top of GEB, while maintaining visualisation and watching the tube pass through the vocal cords.

ETI by paramedics

Paramedics have demonstrated competence with intubation skills across the country, and are encouraged to maintain this skill with continuing professional development (CPD) (Health and Care Professions Council (HCPC), 2012). Deakin et al (2010) indicate that skill fade is much quicker with complex skills and conclusions from their study suggest that paramedics require a considerable amount of training and development.

Most practitioners agree that skills require significant training and ongoing skill maintenance (Strote et al, 2009), and are happy to maintain this with the support of ambulance services. Preventing skill degradation will in turn have a positive effect on patient care; paramedics that feel confident and up-to-date with processes, equipment and the skill of ETI will perform to a high standard in practice, and reduce adverse incidents.

Reducing adverse incidents

Adverse effects that have been identified following ETI are as follows:

This said, over the years, there have been developments to help reduce the number of adverse incidents relating to ETI. Some examples include the provision of various laryngoscopes, the mandated use of GEBs, the use of capnography and end-tidal carbon dioxide (EtCO₂) monitoring, and the development of assisted intubation devices. Since the consistent use of some of these interventions, there has been little evidence presented on the number of ETIs performed, and success rates with adverse effects reported on in the UK. Meanwhile, SGAs are commonly used and there continue to be studies comparing SGAs and ETI in the pre-hospital/out-of-hospital environment, including the large ‘Airways-2’ pre-hospital trial (Taylor et al, 2016).

SGA vs. ETT in the literature

Use of an SGA device can help overcome some of the problems which arise with ETI, such as lack of time, unavailable equipment and skill degradation. Insertion of a SGA requires minimal training and takes a short amount of time (Park et al, 2016). However, a large study in Europe found that the overall success rate of ETI was higher than that of SGAs when carried out by paramedics (Henline et al, 2014). Also comparing the time and success rates of SGAs and ETI, Frascone et al (2011) found no differences in placement success, rate or time between an SGA and ETT. On the other hand, Chen and Hsiao (2008) compared ETI to the insertion of an SGA in paediatrics. They found that the use of an SGA led to a quicker time to ventilate, and had fewer complications when performed by out-of-hospital care providers.

A large review by Wang and Yealy (2013) found that ETI was associated with improved outcomes over SGA insertion after out-of-hospital cardiac arrest (OHCA). A few years later, Benoit et al (2015) carried out a large review and found similar results; that patients in OHCA have a better chance of survival and neurological outcomes if they are intubated. When considering OHCA, Soar et al (2015) found that outcome is not improved by ETI.

Stone et al (1998) found that SGAs are a good alternative to bag-mask ventilation and are associated with less aspiration of gastric contents. However, when compared to an ETT, both the LMA and iGel did not protect the lungs from aspiration in a study by Piegeler et al (2016). According to Simons et al (2007), regurgitation of gastric contents occurs in three-quarters of patients in cardiac arrests, and is associated with decreased odds of survival to hospital discharge. Approaches that treat or prevent regurgitation (i.e. ETI) may therefore improve the chances of survival following cardiac arrest. In line with this, Professor Frédéric Adnet from France presented his large study with a sample size of more than 2000, at the European Society of Cardiology (ESC) Congress, and reported that incidences of regurgitation were much fewer with ETI using an ETT (ESC, 2017).

Further limitations to the use of SGAs include the need for higher peak inspiratory pressures, which in turn disrupt the seal of the device (Guyette et al, 2007). Baker and Webber (2011) also found that SGAs often have ineffective ventilation control for patients with low chest compliance (particularly those in established cardiac arrest).

Case-note review

The case-note review presented in the current article investigated existing practice by paramedics, in terms of airway management for patients in cardiac arrest. The review was carried out to identify current practice relating to airway management and intubation in the pre-hospital environment.

Data were gathered about the number of cardiac arrests and the airway management techniques used during CPR, in one area of the UK. Airway techniques ranged from manual manoeuvres with adjuncts such as oral pharyngeal airways (OPAs), to ETI using an ETT.

Method

Retrospective data were collected from the adult patients (over the age of 18) in cardiac arrest (including traumatic cardiac arrest), that were attended to and resuscitated by paramedics in one region of the UK. The region supports ETI by paramedics in practice, following appropriate training.

The questions asked were:

Data were collected over the period of a year from April 2014 to March 2015, avoiding the initial national Airways-2 trial data-collection period. All the adult cardiac arrests attended to by the ambulance service in the 1-year collection period were included in the study. A data-sharing agreement was approved by the selected ambulance service in the region. Data were extracted by the service and presented to the author in a grouped, tabular format, giving number of cardiac arrests and airway adjuncts used. No personal identifiable data were shared and ethical approval was not required from the NHS Health Research Authority (NHS HRA) (2015) as the research did not use NHS patients or human tissue samples. Throughout the study, the code of Ethics and Conduct from the Nursing and Midwifery Council (NMC) and the HCPC were adhered to. At all times, anonymity and confidentiality were maintained; the researcher was not able to see patient or practitioner details.

Airway adjuncts for cardiac arrest

A total of 3872 cardiac arrests were recorded, of which 72% (n=2779) were resuscitated. All airway adjuncts used during CPR (OPA, nasopharyngeal airway (NPA), SGA and ETT), as well as the success rates of these, are reflected in the data. Figure 5 shows the type of airway, the frequency of use and success rate in CPR over the 1-year period.

Of the airway adjuncts available, 493 OPAs (17.7% of cardiac arrest patients) and 69 NPAs (2.5% of cardiac arrest patients) were inserted. The success rate was high; 99.4% successful OPA insertions and 95.7% successful NPA insertions.

SGAs were inserted in less than half of the cardiac arrest patients (n=1346; 48.4%). This was either an iGel or an LMA, for which success rates were again high (Figure 6). The data show that 691 LMAs (24.9% of cardiac arrest patients) and 655 iGels (23.6% of cardiac arrest patients) were inserted. In most of these cases, either an LMA or an iGel would have been used, depending on the region and equipment sourced. The success rates were 96.8% for LMAs and 95.4% for iGels, averaging 96.1% for total SGAs inserted.

The number of ETI attempts made during cardiac arrests over the data-collection period was less than that of SGAs. Just 41.6% of cardiac arrest patients (n=1157) had intubation attempted (Figure 5; Figure 7). Of these attempts, the success rate was 76.8% (n=889). Thus only 32% of patients in cardiac arrest were successfully intubated (Figure 7). The total number of intubation attempts (n=1157) led to 268 (23.2%) unsuccessful or failed intubations.

Discussion

A reason for not carrying out resuscitation, as was the case in 28% (n=1093) of the patients attended, may be the patient having an advanced decision to refuse treatment, such as a ‘do not attempt cardiopulmonary resuscitation’ (DNACPR) order. Another reason is that attempts would be futile, for example if rigour, algor or livor mortis was apparent. Otherwise, attempts should be made to resuscitate patients in sudden cardiac arrest, following the advanced life support algorithm. This involves carrying out chest compressions and managing the patient's airway, with adjuncts as required.

As a result of the suggested step-wise approach taken in airway management, more than one airway may have been used in each arrest. Unfortunately, data-sharing limitations did not support the collection of airway adjuncts used in independent cardiac arrest cases. The number of OPAs and NPAs used was low, given that following the commencement of chest compressions, airway management is the first step of cardiac arrest management. This indicates that a step-wise approach is not taken, which may be attributed to a patient being in cardiac arrest on initial assessment. In these cases, the patients may have had an SGA inserted or been intubated immediately (Wang and Yealy, 2013).

Of 2779 resuscitated cardiac arrest patients, less than half had an SGA inserted. The use of iGels and LMAs was being routinely taught in training schools and universities by 2014 and 2015, which does not explain the reason for under-use. It could be that those patients that didn't have an SGA inserted had attempted intubation instead. However, the results show that 1157 endotracheal intubations were attempted, which was less than half (41.6%) of the patients in cardiac arrest.

It is impossible to draw from the case-note review results the reasons why intubation was attempted in less than half of the patients in cardiac arrests and failed in 23.1% of attempts. Evidence from the literature suggests that paramedics do not feel confident owing to skill fade and not performing ETI in practice regularly (Strote et al, 2009; Deakin et al, 2010). The results also support the literature, that suggests that adverse effects during ETI, including failed attempts, are prevalent.

Additionally, there appears to be conflict in the guidelines regarding best practice for airway management during cardiac arrest, and whether to ‘upgrade’ the airway to an ETT. The step-wise airway management approach in cardiac arrest is advocated by the Resuscitation Council UK (2015), which advises that simple airways such as SGAs enable oxygenation and ventilation to be achieved rapidly. Other study results suggest early ETI will:

The case-note review results are unable to distinguish whether an ETT was used in place of an SGA.

With their introduction to the pre-hospital environment, use of SGAs has been encouraged following a step-wise airway management process (Resuscitation Council UK, 2015). SGAs can be used by any level of personnel in the ambulance service—for instance, ECAs, ambulance technicians and paramedics. In the current review, it was not possible to determine the level of responder to the cardiac arrest; if a paramedic was not present, the highest step of airway management reached would be SGA insertion.

Service guidelines indicate that paramedics should be deployed to all cardiac arrests where possible, further suggesting that ETI would be a possibility in all cardiac arrests. Evidence proposes that ETI should be attempted in cardiac arrests (Frascone et al, 2011; Wang and Yealy, 2013; Benoit et al, 2015). Practice guidelines should be clear in terms of expectations around intubation attempts. At the same time, services should support paramedics with relevant training and skill maintenance opportunities. Providing adequate resources, such as appropriately sized blades and assisting intubation equipment, for paramedics to carry out safe effective intubation, is also essential. At the same time, paramedics have a responsibility to maintain their CPD with knowledge and skills for up-to-date practice, including equipment and guidelines (HCPC, 2012).

Limitations

Patients who were ‘peri-arrest’ may have had airway adjuncts inserted prior to witnessed cardiac arrest (if personnel were on scene prior to the cardiac arrest). Unfortunately, it was not possible to ascertain whether patients were in cardiac arrest prior to personnel arriving or not. It was also not possible to determine the level of personnel that attended each cardiac arrest; ECA, technician or paramedic. ECAs and technicians do not intubate as part of their skill set, though are able to insert SGAs (LMA or iGel).

There may also be a limitation in reporting; the current review relied on accurate documentation of airway management techniques and it has been found that documentation of successful ETI can be suboptimal (Phelan et al, 2013). The availability and arrangement of data allowed for descriptive statistical analysis only. Comprehensive, inferential statistical analysis may lead to robust conclusions being drawn from the results, on which practice could be based.

Summary

The current article considers airway management and ETI by paramedics in the out-of-hospital environment. Paramedics are trained to perform airway management using a step-wise approach. Studies comparing ETTs to SGAs are inconclusive regarding the most effective method for patient outcome. The results of the national Airways-2 trial may provide comprehensive insight into this.

Paramedics are trained and supported to carry out ETI for patients in cardiac arrest. Despite changes in guidance, it is suggested that paramedics will continue to need to perform advanced airway management techniques in the out-of-hospital environment. The literature proposes that ETI should be employed by those trained appropriately with adequate skills, experience and exposure to ETI. Training is clearly a huge component and whichever method of airway management is established, adequate training and skill maintenance is imperative to enhance practice.

The case-note review results relating to airway management techniques used in CPR, suggest that a variety of airways are used during cardiac arrest. They indicate that a step-wise approach is not taken to airway management in many cases, with the low number of OPAs and NPAs used. For patients in established cardiac arrest when ambulance personnel arrive on scene, an SGA may have been inserted as the first airway. This said, less than half of the patients in cardiac arrest had an SGA inserted (48%) and it is unclear whether the remainder were intubated. Success rates for the use of simple adjuncts (OPAs, NPAs and SGAs) was high when they were used in practice.

In some cases, ETI may have been the first airway management choice for patients in cardiac arrest. However, less than a third of the patients in cardiac arrest were successfully intubated (32%) and attempts were not made to intubate over half of the patients (n=1622; 58.4%). Reasons for unsuccessful intubation are unknown and further study is required to investigate this phenomenon. Once established, these should be incorporated into a rigorous training and development programme for paramedic practitioners.

Key Points

CPD Reflection Questions