Sellick Maneuver

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Continuing Education Activity

Cricoid pressure is a technique that has become part of rapid sequence intubation to prevent aspiration of gastric contents. Although limited evidence supports its utility, it is still recommended in select populations. This activity reviews the technique, indications, and contraindications of the cricoid pressure procedure and highlights the role of an interprofessional team in applying this technique.

Objectives:

  • Identify the proposed mechanism of cricoid pressure.

  • Determine the structures of the cricoid pressure unit.

  • Apply the current guidelines/practice recommendations involving cricoid pressure.

  • Communicate the importance of an interprofessional care team in caring for patients requiring intubation to advance the cricoid pressure technique and improve clinical outcomes.

Introduction

Aspiration pneumonitis and pneumonia are significant complications associated with anesthetic management. Indeed, aspiration pneumonia was identified as the most important contributor to deaths among all pneumonia etiologies investigated.[1] As many as 15% of all anesthesia malpractice claims in the United States are related to aspiration.[2] Furthermore, it has been shown that aspiration was associated with the highest mortality rate of anesthesia-related reported airway difficulties in 1 study from the United Kingdom (UK) (n=133). It was the second most frequently reported airway complication, surpassed only by difficult intubation.[2]

Sellick proposed a method of esophageal compression to avoid aspiration of gastric contents in preparation for intubation. The eponymously named “Sellick Maneuver” is now commonly called cricoid pressure. This method has been widely adopted and thoroughly investigated following its introduction in 1961. Arguably, 1 of its most distinctive features is that it has become an integral part of rapid sequence intubation, pre-oxygenation, and short induction to intubation interval.[3]

Cricoid pressure has been shown to attenuate the incidence of aspiration mainly through posterior compression of the cricoid cartilage. The cricoid cartilage is a complex, ring-like structure inferior to the cricothyroid cartilage at level C6. Sellick documented that this compression occludes the esophagus at C5, whereas other studies, aided by advanced imaging technologies, have specified the post-cricoid hypopharynx as the likely target. The post-cricoid hypopharynx includes the cricopharyngeus as a component of the upper esophageal sphincter.[4]

Anatomy and Physiology

The cricoid cartilage can be identified by palpating the hard ridge on the inferior border of the cricothyroid membrane. The arch of the cricoid cartilage, the anterior portion of the signet ring shape, is at the level of the body of C6. This is the same level as the carotid tubercle. A moderate agreement was found between these landmarks with a fluoroscopic study, including non-obese patients performing neck extension. However, the study found the cricoid cartilage slightly superiorly placed between the C5 and C6 vertebral bodies, compared to previous reports.[5]

The inner shape of the cricoid cartilage varies, with ovoid, oval, and pear-shaped being the most common types. The shape is similar to a signet ring with the broader end, known as the lamina, found posteriorly.[6]

Sellick initially hypothesized that the cricoid cartilage was directly opposed to the esophagus and that posteriorly directed force would occlude the esophagus between the C5 vertebral body and the rigid cricoid cartilage, thus preventing aspiration of gastric contents.[7] Intragastric pressures up to 40 mmHg have been recorded as precluded by applying cricoid pressure. In the clinical setting, intragastric pressures rarely exceed 25 mmHg without extenuating circumstances such as obesity, trauma, and other pathological states.[8]

However, it is now believed that the hypopharynx is the target of cricoid pressure as the esophagus begins inferior to the level of the cricoid ring. The cricopharyngeal muscle is a significant component of the cricoid pressure unit and is located on the posterolateral hypopharynx at the lower border of the cricoid ring. Additionally, the tendinous band is attached to the cricoid perichondrium and transverse and oblique aponeuroses of the arytenoid muscles. These structures maintain a fixed relationship between the cricoid ring and the hypopharynx. The collapse of the musculature, which results in a kidney shape during cricoid pressure, is a significant factor in impeding regurgitation. Furthermore, occlusion of the hypopharynx may be attributed to the bulkier composition of the anterior tissue of the gastroesophageal tract 1cm below the cricoid.[9] 

Despite a substantial proportion of the population having a laterally displaced esophagus and cricoid pressure resulting in lateral displacement, the technique is thought to be unaffected as the hypopharynx is the target. Paralaryngeal and paratracheal approaches to occluding the esophagus have been proposed due to the ability to maintain a patent airway with limited success of esophageal occlusion compared to cricoid pressure.[8]

Indications

Cricoid pressure is indicated in patients with an elevated risk of aspiration. Common indications for implementing cricoid pressure include patients who have recently eaten, gastroparesis, gravidity, nausea, recently vomited, hiatal hernia, or known incompetent esophageal sphincter(s), increased intraabdominal pressure, inebriation, impaired neurological, or upper respiratory reflexes. Cricoid pressure is commonly used in emergency settings as multiple attempts at intubation, emergent situations, and patients of elevated American Society of Anesthesiology (ASA) status are more prone to aspiration events.[4]

The most emphasized demographic for the use of cricoid pressure is obstetrical patients.[10]

Contraindications

The contraindications associated with the Sellick maneuver include the following:

  • Although considered a rare event, Sellick indicates that cricoid pressure may be detrimental in the context of ongoing vomiting with concern for esophageal rupture as the vomitus dilates the esophagus against a closed cricopharyngeus.[7] 
  • A relative contraindication is a cervical injury, as posteriorly directed pressure may act as an exacerbating factor.[10]
  • It is recommended that cricoid pressure is released if there is a poor laryngeal view during the insertion of a supraglottic airway device.[11]

Equipment

The procedure was initially described as employing an assistant's hand. It is possible to attain adequate technique and pressure using only the fingers; however, devices have also been introduced to minimize the equivocal effectiveness of the classicly described approach.

For example, a tactile feedback device using the exact finger placement as Sellick initially instructed has been found to most consistently provide the appropriate pressure and also decrease upward bias in applied force.[12] Similarly, a device that illuminates when the proper pressure has been achieved has been described.[13] These devices are considered more straightforward and consistent than the manual approach.

Personnel

At least 2 practitioners are required to perform intubation during cricoid pressure. The cricoid pressure should not be released until the patient is intubated with the cuff inflated; therefore, it would be prohibitively challenging for 1 person to perform both tasks simultaneously. 

Preparation

Proper training of all staff who may provide cricoid pressure is highly recommended. Studies have demonstrated a training gap regarding consistently and appropriately applied pressure and knowledge of the anatomical location of the cricoid.[14]

Technique or Treatment

The most common technique for cricoid pressure involves at least a 2 person team. As 1 individual intubates the patient, the other performs the cricoid pressure maneuver. 

The patient is classically placed in a supine position with the neck extended. Alternatively, to facilitate the view of the glottis, the patient may have his or her lower cervical spine flexed with the upper cervical spine extended in the “sniffing position.” The benefit of neck extension, as observed by Sellick, is that vomitus is directed away from the airway.[7]

The practitioner performing the maneuver often stands on the patient's right side. The practitioner uses anatomical landmarks, including the thyroid cartilage and cricothyroid membrane, to identify the cricoid ring. Once identified, the practitioner may use the dominant hand or whichever hand can most apply appropriate pressure without impeding the team member's function performing the intubation. The thumb remains on the patient’s right side of the cricoid ring, with the second digit placed on the contralateral side of the cricoid ring. The practitioner may place the third digit on the same side as the second digit if this is found to be more comfortable. While the patient is awake, a 10 N or 1 kg pressure is appropriate until induction is complete. Once the patient is unconscious, approximately 30 N or 3 kg are applied posteriorly to the cricoid ring. The constant pressure should be maintained until the endotracheal tube is appropriately placed with the cuff inflated to protect the airway. When applying cricoid pressure in pediatric patients, the pressure should be decreased, considering the increased deformability of soft structures.[15][4][16] A pressure of 20 N is effective when the patient is in a head-up position.[17]

A double-handed maneuver may be implemented when there is a concern for cervical spine instability. In such situations, the practitioner uses his or her free hand to support the posterior cervical spine while providing cricoid pressure.[4]

It is generally recommended that gastric tubes be used before intubation in patients with a full stomach. Sellick initially believed that cricoid pressure would be ineffective while a gastric tube was in place. This concern was unsubstantiated as subsequent studies have demonstrated that the tube deviates to the side of the esophagus with occlusion possible.[7][4] Cricoid pressure should not be confused with a technique commonly referred to as “BURP” (backward, upward, rightward pressure on the thyroid cartilage), used to aid in visualizing the glottis during intubation.[4]

Complications

Discomfort, retching, and nausea may be observed in awake or under-anesthetized patients. More severe complications would include airway compromise, traumatization in the under-anesthetized, esophageal rupture, cricoid fracture, and potential worsening of cervical spine injuries.[4] Some complications may be avoided by waiting until induction is complete, applying proper pressure to the cricoid, and effectively supporting the cervical spine while performing the maneuver. There are concerns about arterial compression with some cricoid devices that are being investigated.[12] 

One study found that the incidence of significantly longer intubation time and higher Lehane and Cormack scores indicate that intubation may be more challenging in the cricoid pressure versus the sham group. There was no significant difference in traumatic intubations between the sham and cricoid pressure groups. There was no difference in mortality, length of stay, or aspiration. However, the prevalence of aspiration was low in the study at 0.5%, with pregnant patients (emergent cases not included).[18]

Clinical Significance

The evidence for the widespread application of cricoid pressure is equivocal. The American Heart Association removed cricoid pressure from in-hospital and out-of-hospital resuscitation algorithms. This information was based on practitioners' ineptitude at correctly performing the technique on mannequins.[19] In conjunction with the Obstetric Anesthetist's Association, the Difficult Airway Society recommends using cricoid pressure during rapid sequence intubation in the high-risk demographic of parturient patients.[11] The Difficult Airway Society guidelines also recommend its use outside of obstetrics.[10] Much of the debate concerning the effectiveness of cricoid pressure focuses on the inconsistent and improper application of the technique. A study comparing no use of cricoid pressure to a uniformly applied pressure at the confirmed anatomical location in both high-risk and low-risk cohorts would be invaluable in putting the controversy to rest.

Increased support for cricoid pressure in the United States compared to the rest of the globe is attributed to more significant concerns about medico-legal entanglements. There is a low level of evidence by expert consensus for using cricoid pressure. Despite its use, aspiration is not entirely preventable. 

Enhancing Healthcare Team Outcomes

The controversy over cricoid pressure results from low-level evidence for its effectiveness and often incorrect use. Numerous studies have assessed the knowledge base of various interprofessional team members, including clinicians, nurses, respiratory therapists, medical students, paramedics, nurse anesthetists, and anesthesia assistants. Results from these studies often demonstrate a lapse in knowledge regarding effective techniques. The most prominent issues include the misidentification of anatomy and improperly applied pressure. One meta-analysis identifies that staff lacking training in rapid sequence intubations could be asked to assist during emergent intubations. The low evidence for cricoid pressure's prevention of aspiration may be attributed to undertraining and inconsistent application.[19] Interprofessional coordination can help assign the most qualified and competent team member when the Sellick maneuver is necessary, plus additional training for all team members.

Tools for improving consistency include regular training and the use of assistive devices. In emergent settings, anesthesia staff who would be expected to be familiar with cricoid pressure may not be available. Preparation for such scenarios involves regular training of anesthesia staff and support staff commonly present during emergent intubations, such as nurses, respiratory therapists, surgical technicians, and others.

Nursing, Allied Health, and Interprofessional Team Interventions

As mentioned, all staff involved in rapid sequence intubation should be trained regularly on effective cricoid pressure techniques. Rapid-sequence intubation requires a team of 2 or more individuals. One individual is likely the anesthesia provider for the case, and the other individual could be any other team member involved in patient care when intubation is commonly indicated. Meta-analysis has identified that verbal instruction is inferior to hands-on learning cricoid pressure techniques.[14]

Nursing, Allied Health, and Interprofessional Team Monitoring

Most trainees from a meta-analysis were identified as unskilled in cricoid pressure application; however, there was demonstrable improvement following simulation training. Skill retention following training endures for 3 weeks as a conservative estimate.[14] Considering contemporary literature documenting the poor retention of these skills and the unlikely nature of most practitioners providing cricoid pressure multiple times daily outside of the obstetrics and trauma units, there is a compelling indication to reassess and retrain team members regularly.


Details

Editor:

Mark F. Brady

Updated:

1/29/2023 9:19:53 AM

References


[1]

Mandell LA, Niederman MS. Aspiration Pneumonia. The New England journal of medicine. 2019 Feb 14:380(7):651-663. doi: 10.1056/NEJMra1714562. Epub     [PubMed PMID: 30763196]


[2]

Cook TM, Woodall N, Frerk C, Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. British journal of anaesthesia. 2011 May:106(5):617-31. doi: 10.1093/bja/aer058. Epub 2011 Mar 29     [PubMed PMID: 21447488]


[3]

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[4]

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Level 3 (low-level) evidence

[5]

Siribumrungwong K, Sinchai C, Tangtrakulwanich B, Chaiyamongkol W. Reliability and Accuracy of Palpable Anterior Neck Landmarks for the Identification of Cervical Spinal Levels. Asian spine journal. 2018 Feb:12(1):80-84. doi: 10.4184/asj.2018.12.1.80. Epub 2018 Feb 7     [PubMed PMID: 29503686]


[6]

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[7]

SELLICK BA, Cricoid pressure to control regurgitation of stomach contents during induction of anaesthesia. Lancet (London, England). 1961 Aug 19;     [PubMed PMID: 13749923]


[8]

Kim H, Chang JE, Won D, Lee JM, Jung JY, Choi S, Min SW, Hwang JY. The effect of cricoid and paralaryngeal force on upper oesophageal occlusion during induction of anaesthesia: a randomised, crossover study. Anaesthesia. 2020 Feb:75(2):179-186. doi: 10.1111/anae.14873. Epub 2019 Oct 21     [PubMed PMID: 31631314]

Level 1 (high-level) evidence

[9]

Miwa K, Tsutsumi M, Fukino K, Eguchi K, Okada R, Akita K. An anatomical study of the anterior wall of the hypopharyngeal and the cervical esophageal junction. Auris, nasus, larynx. 2020 Oct:47(5):849-855. doi: 10.1016/j.anl.2020.04.005. Epub 2020 May 4     [PubMed PMID: 32376069]


[10]

Zdravkovic M, Rice MJ, Brull SJ. The Clinical Use of Cricoid Pressure: First, Do No Harm. Anesthesia and analgesia. 2021 Jan:132(1):261-267. doi: 10.1213/ANE.0000000000004360. Epub     [PubMed PMID: 31397697]


[11]

Mushambi MC, Kinsella SM, Popat M, Swales H, Ramaswamy KK, Winton AL, Quinn AC, Obstetric Anaesthetists' Association, Difficult Airway Society. Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics. Anaesthesia. 2015 Nov:70(11):1286-306. doi: 10.1111/anae.13260. Epub     [PubMed PMID: 26449292]


[12]

Taylor RJ, Smurthwaite G, Mehmood I, Kitchen GB, Baker RD. A cricoid cartilage compression device for the accurate and reproducible application of cricoid pressure. Anaesthesia. 2015 Jan:70(1):18-25. doi: 10.1111/anae.12829. Epub 2014 Sep 29     [PubMed PMID: 25267415]


[13]

Lawes EG. Cricoid pressure with or without the "cricoid yoke". British journal of anaesthesia. 1986 Dec:58(12):1376-9     [PubMed PMID: 3790389]


[14]

Johnson RL, Cannon EK, Mantilla CB, Cook DA. Cricoid pressure training using simulation: a systematic review and meta-analysis. British journal of anaesthesia. 2013 Sep:111(3):338-46. doi: 10.1093/bja/aet121. Epub 2013 Apr 23     [PubMed PMID: 23611912]

Level 1 (high-level) evidence

[15]

Andruszkiewicz P, Zawadka M, Kosińska A, Walczak-Wieteska P, Majerowicz K. Measurement of cricoid pressure force during simulated Sellick's manoeuvre. Anaesthesiology intensive therapy. 2017:49(4):283-287. doi: 10.5603/AIT.a2017.0049. Epub 2017 Sep 27     [PubMed PMID: 28953309]


[16]

Landsman I. Cricoid pressure: indications and complications. Paediatric anaesthesia. 2004 Jan:14(1):43-7     [PubMed PMID: 14717873]


[17]

Vanner R. Cricoid pressure. International journal of obstetric anesthesia. 2009 Apr:18(2):103-5. doi: 10.1016/j.ijoa.2009.01.002. Epub 2009 Feb 23     [PubMed PMID: 19233640]


[18]

Birenbaum A, Hajage D, Roche S, Ntouba A, Eurin M, Cuvillon P, Rohn A, Compere V, Benhamou D, Biais M, Menut R, Benachi S, Lenfant F, Riou B, IRIS Investigators Group. Effect of Cricoid Pressure Compared With a Sham Procedure in the Rapid Sequence Induction of Anesthesia: The IRIS Randomized Clinical Trial. JAMA surgery. 2019 Jan 1:154(1):9-17. doi: 10.1001/jamasurg.2018.3577. Epub     [PubMed PMID: 30347104]

Level 1 (high-level) evidence

[19]

Beckford L, Holly C, Kirkley R. Systematic Review and Meta-Analysis of Cricoid Pressure Training and Education Efficacy. AORN journal. 2018 Jun:107(6):716-725. doi: 10.1002/aorn.12150. Epub     [PubMed PMID: 29851051]

Level 1 (high-level) evidence