Cricoid Force Research Articles

Airway management in patients with suspected or confirmed cervical spine injury: Guidelines from the Difficult Airway Society (DAS), Association of Anaesthetists (AoA), British Society of Orthopaedic Anaesthetists (BSOA), Intensive Care Society (ICS), Neuro Anaesthesia and Critical Care Society (NACCS), Faculty of Prehospital Care and Royal College of Emergency Medicine (RCEM).

There are concerns that airway management in patients with suspected or confirmed cervical spine injury may exacerbate an existing neurological deficit, cause a new spinal cord injury or be hazardous due to precautions to avoid neurological injury. However, there are no evidence-based guidelines for practicing clinicians to support safe and effective airway management in this setting. An expert multidisciplinary, multi-society working party conducted a systematic review of contemporary literature (January 2012-June 2022), followed by a three-round Delphi process to produce guidelines to improve airway management for patients with suspected or confirmed cervical spine injury. We included 67 articles in the systematic review, and successfully agreed 23 recommendations. Evidence supporting recommendations was generally modest, and only one moderate and two strong recommendations were made. Overall, recommendations highlight key principles and techniques for pre-oxygenation and facemask ventilation; supraglottic airway device use; tracheal intubation; adjuncts during tracheal intubation; cricoid force and external laryngeal manipulation; emergency front-of-neck airway access; awake tracheal intubation; and cervical spine immobilisation. We also signpost to recommendations on pre-hospital care, military settings and principles in human factors. It is hoped that the pragmatic approach to airway management made within these guidelines will improve the safety and efficacy of airway management in adult patients with suspected or confirmed cervical spine injury.

Sellick maneuver assisted real-time to achieve target force range in simulated environment-A prospective observational cross-sectional study on manikin.

A force sensor system was developed to give real-time visual feedback on a range of force. In a prospective observational cross-section study, twenty-two anaesthesia nurses applied cricoid pressure at a target range of 30–40 Newtons for 60 seconds in three sequential steps on manikin: Group A (step 1 blinded, no sensor), Group B (step 2 blinded sensor), Group C (step 3 sensor feedback). A weighing scale was placed below the manikin. This procedure was repeated once again at least 1 week apart. The feedback system used 3 different colours to indicate the force range achieved as below target, achieve target, above target. Significantly higher proportion of target cricoid pressure was achieved with the use of sensor feedback in Group C; 85.9% (95%CI: 82.7%-88.7%) compared to when blinded from sensor in Group B; 31.3% (95%CI: 27.4–35.4%). Cricoid force achieved blind (Group B) exceeded force achieved with feedback (Group C) by a mean of 8.0 (95%CI: 5.9–10.2, p<0.0001) and 6.2 (95%CI:4.1–8.3, p< 0.0001) Newtons in round 1 and 2 respectively. Weighing scale read lower than corresponding force sensor by a mean of 8.4 Newtons (95% CI: 7.1–9.7, p<0.0001) in group B and 5.8 Newtons (95% CI: 4.5–7.1, p<0.0001) in Group C. Force sensor visual feedback system enabled application of reproducible target cricoid pressure with less variability and has potential value in clinical use. Using weighing scale to quantify and train cricoid pressure requires a review. Understanding the force applied is the first step to make cricoid pressure a safe procedure.

An international survey about rapid sequence intubation of 10,003 anaesthetists and 16 airway experts.

Pulmonary aspiration of gastric content is a significant cause of anaesthesia-related morbidity and mortality. High-quality prospective randomised evidence to support prevention strategies, such as rapid sequence intubation, is difficult to generate due to well-described practical, ethical and methodological barriers. We aimed to generate an understanding of worldwide practice through surveying clinically practicing anaesthetists and airway experts. Our survey was designed to assess the influence of: departmental standards; patient factors; socio-economic factors; training; and supervision. We surveyed 10,003 anaesthetists who responded to an invitation to participate on LinkedIn. We then surveyed 16 international airway experts on the same content. When asked about a hypothetical patient with intestinal obstruction, respondents expressed preferences for [OR (95%CI)]: the head-up or -down position 4.26 (3.98-4.55), p<0.001; nasogastric tube insertion 29.5 (26.9-32.3), p<0.001; and the use of cricoid force 2.80 (2.62-3.00), p<0.001, as compared with a hypothetical patient without intestinal obstruction also requiring rapid sequence intubation. Respondents from lower income countries were more likely to prefer [OR (95%CI]: the supine position 2.33 (2.00-2.63), p<0.001; nasogastric tube insertion 1.29 (1.09-1.51), p=0.002; and cricoid force application 2.54 (2.09-3.09), p<0.001 as compared with respondents from higher income countries for a hypothetical patient with intestinal obstruction. This survey, which we believe is the largest of its kind, demonstrates that preferences for positioning, nasogastric tube use and cricoid force application during rapid sequence intubation vary substantially. Achieving agreed consensus may yield better training in the principles of rapid sequence intubation.

The effect of cricoid and paralaryngeal force on upper oesophageal occlusion during induction of anaesthesia: a randomised, crossover study.

The aim of this study was to evaluate the effectiveness of cricoid and paralaryngeal force for oesophageal entrance occlusion during induction of anaesthesia. Seventy-four patients were included in this randomised, crossover study. The relative position of the glottis and outer anteroposterior diameter of the upper oesophageal entrance were assessed at baseline, after the application of 30N cricoid and paralaryngeal force, and after induction of anaesthesia. The occlusion rate of the oesophageal entrance with cricoid and paralaryngeal force was assessed during direct laryngoscopy. The relative position of the upper oesophageal entrance to the glottis changed in 45 out of 74 patients after induction of anaesthesia and during direct laryngoscopy compared with the awake state. The application of cricoid and paralaryngeal force decreased the mean (SD) diameter of the upper oesophageal entrance to a similar degree in awake (8.5 (2.1) mm to 6.4 (1.7) mm and 6.5 (1.6) mm, respectively; p<0.001) and anaesthetised (8.7 (2.2) mm to 6.5 (1.7) mm and (6.7 (1.9) mm, respectively; p<0.001) states. During direct laryngoscopy, the occlusion rate of the oesophageal entrance was greater with cricoid compared with paralaryngeal force (46/74 vs. 26/74, respectively; p=0.002). The relative position of the upper oesophageal entrance to the glottis may change after induction of anaesthesia and during direct laryngoscopy. Cricoid and paralaryngeal force both decrease the diameter of the upper oesophageal entrance in awake and anaesthetised states. Occlusion of the oesophageal entrance is achieved more frequently with cricoid force compared with paralaryngeal force during direct laryngoscopy.

The effect of force applied to the left paratracheal oesophagus on air entry into the gastric antrum during positive-pressure ventilation using a facemask.

Cricoid force is widely applied to decrease the risk of pulmonary aspiration and gastric antral insufflation of air during positive-pressure ventilation, yet its efficacy remains controversial. We compared manual oesophageal compression at the low left paratracheal and cricoid levels for the prevention of gastric antral air insufflation during positive-pressure ventilation by facemask in patients scheduled for elective surgery under general anaesthesia. After gaining written consent, participants were randomly allocated by sealed envelope to one of three groups: oesophageal compression by 30 N paratracheal force (paratracheal group); oesophageal compression by 30 N cricoid force (cricoid group); or no oesophageal compression (control group). Gastric insufflation of air was assessed before and after positive-pressure ventilation by ultrasound measurement of the antral cross-sectional area and/or presence of air artefacts in the antrum. The primary outcome measure was the proportion of participants with ultrasound evidence of gastric insufflation. We recruited 30 patients into each group. Before facemask ventilation, no air artefacts were visible in the antrum in any of the participants. After facemask ventilation of the participant's lungs, no air artefacts were seen in the paratracheal group, compared with six subjects in the cricoid group and eight subjects in the control group (p = 0.012). Our results suggest that oesophageal compression can be achieved by the application of manual force at the low left paratracheal level and that this is more effective than cricoid force in preventing air entry into the gastric antrum during positive-pressure ventilation by facemask.

Trainability of Application of the Correct Cricoid Force

Trainability of Application of the Correct Cricoid Force

Miniature Force Sensing System for Monitoring of Optimal Cricoid Pressure for Airway Protection

Application of correct force on cricoid cartilage is an effective approach to prevent the regurgitation of gastric contents. However, the force applied by nurses varies widely, resulting in a proportion of patients remaining at high risk of gastric aspiration due to inadequate force. To guide the nurses to exert consistent and accurate target cricoid force with real time feedback, a flexible, wearable and biocompatible polymer-based force sensor patch was developed, the sensor patch is able to attach on the cricoid cartilage surface. A force read-out system based on printed circuit board was also developed. The light-emitting diodes on the circuit are to indicate the force range. The force sensing system with two sensor patterns ( $3\times 5$ and $10\times 10$ array) were measured on the flat surface, and curved manikin surface. Human subject was involved in the device experimental calibration and verification. The results show that the surface curvature and testing subject are related to the calibration data and measurement accuracy. The measured force accuracy is within ±2.5 N on the manikin surface, and within ±4.0 N on human subject. As a guided fixture was introduced on the sensor patch, the accuracy of the sensor increased to ±1.5 N.

C-MAC© videolaryngoscopy: The anaesthetic assistant's view.

Although videolaryngoscopy plays a major role in the 2015 Difficult Airway Society guidelines, the impact on anaesthetic assistant working practices and training has not previously been reported. We surveyed anaesthetic assistants in our hospital to document their experience with using the C-MAC© videolaryngoscope (48 practitioners, 100% response rate). Improvements in the following were reported: patient safety 100%; ability to see whether laryngoscopy is difficult 98%; ability to anticipate the 'next step' 98%; team-working and human factors 96%; ability to call a senior anaesthetist more quickly 94%; assessment or adjustment of cricoid force application 92%, understanding of laryngeal anatomy 92%; training in intubation 98%; training in cricoid force application 87%. Concerns were primarily about local issues such as decontamination and blade availability. Ninety percent reported that the clinical benefit outweighed any additional workload. In conclusion, the C-MAC© videolaryngoscope is judged by anaesthetic assistants to confer numerous advantages for their working practice and training.

The Cricoid Force Necessary to Occlude the Esophageal Entrance: Is There a Gender Difference?

(Anesth Analg. 2017;124(4):1168–1173) Cricoid force (CF) is used to occlude the esophageal lumen and prevent regurgitation during surgery. However, excessive CF can deform the cricoid cartilage, oppose the vocal cords, interfere with tracheal tube passage, and result in ineffective gas exchange. Due to differences in cricoid plate size, women may require less CF than is recommended in the literature (at least 44 N). The authors of the present study hypothesized that gender differences exist in the necessary CF application to prevent regurgitation. Using a Glidescope video laryngoscope in anesthetized and paralyzed patients, they assessed the effectiveness of different CFs in occluding the esophageal entrance in men and women.

The Cricoid Force Necessary to Occlude the Esophageal Entrance: Is There a Gender Difference?

We tested the hypothesis whether gender differences exist in the applied cricoid force necessary to prevent regurgitation. Real-time visual and dynamic means were used to assess the effectiveness of different applied cricoid forces in occluding the esophageal entrance in men (group 1) and in women (group 2). In anesthetized and paralyzed patients, the glottis and esophageal entrance were visualized with a Glidescope video laryngoscope. Trained operators performed cricoid pressure (CP) and gastric tube insertion trials. Successful gastric tube insertion in the presence of CP was considered ineffective CP, whereas unsuccessful insertion was considered effective CP. The applied cricoid forces were measured with a novel instrument, the cricometer. The first patient in each group received 20 N. The applied cricoid force in successive patients was determined by the response of the previous patient within the same group, using the up-and-down sequential allocation technique. In the 30 men and 30 women who qualified for the study, the median cricoid force (cricoid force = 50) that occluded the esophageal entrance was 30.8 N (95% confidence interval = 28.15-33.5) in men, and 18.7 N in women (95% confidence interval = 17.1-20.3; P < .0001). Patency of the esophageal entrance was observed when CP was not applied and when inadequate forces that allowed successful esophageal cannulation were used. The current study provides evidence that the median force necessary to occlude the esophageal entrance to prevent regurgitation is less in women compared with men. Applying the appropriate cricoid force in women should also decrease airway-related problems that tend to occur with the use of excessive forces. The findings of the current study may only be applicable to patients with normal body habitus.

Cricoid Pressure Controversies: Narrative Review.

Since cricoid pressure was introduced into clinical practice, controversial issues have arisen, including necessity, effectiveness in preventing aspiration, quantifying the cricoid force, and its reliability in certain clinical entities and in the presence of gastric tubes. Cricoid pressure-associated complications have also been alleged, such as airway obstruction leading to interference with manual ventilation, laryngeal visualization, tracheal intubation, placement of supraglottic devices, and relaxation of the lower esophageal sphincter. This review synthesizes available information to identify, address, and attempt to resolve the controversies related to cricoid pressure. The effective use of cricoid pressure requires that the applied force is sufficient to occlude the esophageal entrance while avoiding airway-related complications. Most of these complications are caused by excessive or inadequate force or by misapplication of cricoid pressure. Because a simple-to-use and reliable cricoid pressure device is not commercially available, regular training of personnel, using technology-enhanced cricoid pressure simulation, is required. The current status of cricoid pressure and objectives for future cricoid pressure-related research are also discussed.

Measurement of cricoid pressure force during simulated Sellick's manoeuvre.

Cricoid pressure is a standard anaesthetic procedure used to reduce the risk of aspiration of gastric contents during the induction of general anaesthesia. However, for several years its validity has been questioned. There still remains the question of whether we perform it correctly. The aim of the study was an evaluation of the theoretical knowledge of Sellick's manoeuvre, as well an assessment of practical skill related with it when simulated on a model of the upper airway. The study was performed on a cohort of anaesthetists and anaesthetic nurses working in various hospitals in the Warsaw area. Measurements were taken on an upper airway model placed on an electronic kitchen scale. Participants were asked to perform Sellick's manoeuvre in the way they do it in their clinical practice. The test was done twice. Both the position and pressures applied on the model were documented. Knowledge concerning current recommendations of cricoid force was noted. 206 subjects participated in the study. Only 49% (n = 101) properly identified cricoid cartilage during their application of Sellick's manoeuvre. Application of the correct pressure on the model of the airway was noted in 16.5% (n = 34) during the first attempt and in 20.4% (n = 42) during the second attempt. The median force applied during simulated Sellick's manoeuvrewas 36 N (IQR: 26-55) in the first attempt, and 38 (IQR 25-55) in the second attempt. Sellick's manoeuvre was performed incorrectly in many cases. Half of the participants of our study applied the pressure in the wrong place while the majority of them used an inappropriate amount of force. Thus, the application of cricoid pressure in patients should be preceded with simulation training.

The Effectiveness of Cricoid Pressure for Occluding the Esophageal Entrance in Anesthetized and Paralyzed Patients

In the last 2 decades, the effectiveness of cricoid pressure (CP) in occluding the esophageal entrance has been questioned. Recent magnetic resonance imaging studies yielded conflicting conclusions. We used real-time visual and mechanical means to assess the patency of the esophageal entrance with and without CP in anesthetized and paralyzed adult patients. One hundred seven, nonobese ASA physical status I and II patients were recruited for the study. A cricoid force of 30 N was used. This force was standardized by using a weighing scale before application of CP in each patient. After oxygen administration, anesthetic induction, neuromuscular blockade, and establishment of manual ventilation with FIO2 = 1.0, the view of the glottis and esophageal entrance was visualized, and video recordings were obtained by using a Glidescope video laryngoscope. Attempts to insert 2 gastric tubes (GTs), size 12 and 20 F, into the esophagus were made by a "blinded" operator without and with CP, the timing of which was randomized. A successful insertion of a GT in the presence of CP was considered evidence of a patent esophageal entrance (ineffective CP), whereas an unsuccessful insertion of a GT was considered evidence of an occluded esophageal entrance (effective CP). After the attempts to insert the GTs were completed, tracheal intubation was performed while CP was applied. The position of the esophageal entrance in relation to the glottis (midline versus lateral) was assessed from the video recordings, with and without CP. We stopped the study when 79 patients (41 men and 38 women) qualified for and completed the study (2-sided Clopper-Pearson confidence interval (CI) 95% to 100%, n = 72). Advancement of either size GT into the esophagus could not be accomplished during CP in any patient but was easily done in all subjects when CP was not applied. This occurred whether the esophageal entrance was in a midline position or in a left or right lateral position relative to the glottis. Esophageal patency was visually observed in the absence of CP, whereas occlusion of the esophageal entrance was observed during CP in all patients. Without CP, the esophageal entrance was in a left lateral position in relation to the glottis in 57% ([95 % CI, 45%-68%)] of patients, at midline in 32% (CI, 22%-43%), and in a right lateral position in 11% (CI, 5%-21%). The position did not change with CP. The current study provides additional visual and mechanical evidence supporting a success rate of at least 95% by using a cricoid force of 30 N to occlude the esophageal entrance in anesthetized and paralyzed normal adult patients. The efficacy of the maneuver was independent of the position of the esophageal entrance relative to the glottis, whether midline or lateral.

Effect of Cricoid Force on Airway Calibre in Children

Survey of Anesthesiology: August 2010 - Volume 54 - Issue 4 - p 180-181 doi: 10.1097/01.SA.0000377122.33683.8a

Effect of cricoid force on airway calibre in children: a bronchoscopic assessment

Cricoid pressure or to be more exact cricoid force (CF) can cause airway obstruction and subsequent difficulty with airway management during an emergency induction. We studied 30 children with an age range of 3 months to 15 yr who presented for routine bronchoscopy or other surgical procedures requiring tracheal intubation. We looked at the effect of CF on the calibre of the subglottic airway and objectively measured the force which caused 50% or greater distortion/compression of the subglottic airway. There was a linear relationship between both age and weight and CF. No patient suffered any adverse effects. Overall, the mean force required to compress the airway was 10.5 N. However, this force could be as low as 5 N in children <1 yr of age, and up to between 15 and 25 N in teenagers. Forces well below the recommended value of 30 N will cause significant compression/distortion of the airway in a child.

Knowledge, Attitude, and Practice Regarding Cricoid Pressure of ED Personnel at a Large U.S. Teaching Hospital

Application of cricoid pressure (CP) is an important step during rapid sequence intubation. Previous surveys of anesthesia personnel showed a knowledge deficiency in the recommended level of cricoid force. There has been no previous attempt to assess the adequacy of knowledge of ED personnel in the application of CP. The objective of this study was to assess the theoretic knowledge of ED personnel about CP. We carried out a convenience sample of all ED personnel present at the morbidity and mortality meeting of a major US teaching hospital. A questionnaire-based survey was distributed; respondents were unaware of the questions or the nature of the survey before participating. In total, 83 completed questionnaires were returned by 38 residents, 25 attending physicians, and 20 nurses. Many of the respondents knew the anatomic structure to which CP is applied. However, 24 respondents (14 nurses and 10 residents) thought that CP is applied to both the cricoid and thyroid cartilage. Interestingly, 70% of the nurses in this survey gave an incorrect response to the question on the anatomic localization of CP. Many of the participants in this survey either were unsure of the recommended amount of cricoid force in the asleep patient or quoted values that were too low. The majority of respondents rated their training in CP application as either poor or nonexistent. Most were able to name 2 contraindications to the application of CP. The theoretic knowledge about CP is poor in this survey from staff at a major US teaching hospital. Poor theoretic knowledge could lead to poor technique in the application of CP. More specific education and training are needed to improve the clinical use of CP and possibly increase patient safety.

Practice makes perfect? Evaluation of cricoid pressure task training for use within the algorithm for rapid sequence induction in critical care

To assess task training in cricoid pressure application suitable for incorporation into the algorithm for rapid sequence induction in acute care. A blinded prospective direct observational study of 110 critical care staff of two hospitals in regional New South Wales. Each participant was instructed to apply blinded cricoid force within the target range of 30-40 N to a cricoid model mounted on a weighing scale and the result recorded. After up to 3 min of unblinded practice without coaching on the same model a repeat blinded application of force was recorded. The pre- and post-intervention results were compared. At the pre-intervention stage, 22 participants (20%) applied initial pressure within the target range, increasing to 57 (52%) at the post-intervention stage (chi(2) = 24.19, d.f. = 1, P < 0.01; odds ratio [OR] = 0.23; 95% confidence interval [CI] 0.12-0.44). The post-intervention results show a significant improvement in the number of participants achieving the target range in both nursing (chi(2) = 20.42, d.f. = 1, P < 0.01; OR = 0.18; 95% CI 0.08-0.42) and medical subgroups (chi(2) = 4.68, d.f. = 1, P = 0.03; OR = 0.34; 95% CI 0.11-1.02). The number applying force sufficient to prevent regurgitation, that is 30 N or greater, rose from 71 to 97 (65% to 88%) (chi(2) = 17.02, d.f. = 1, P < 0.01; OR = 0.24; 95% CI 0.11-0.51). The number applying in excess of 44 N fell from 41 to 25 (37% to 21%) (chi(2) = 5.54, d.f. = 1, P < 0.02; OR = 2.02; 95% CI 1.08-3.81). The application of cricoid force by critical care staff can be significantly improved by up to 3 min of practice on a simple task trainer.

Assessment of cricoid pressure application by emergency department staff

To assess the accuracy of cricoid force applied by ED staff working in two hospitals based on the New South Wales central coast. A prospective, observational study of 38 doctors and 69 nurses working in the ED. Each staff member was asked to demonstrate cricoid pressure using a model based on a set of weighing scales. Five attempts were measured and a mean value calculated for each participant. Subgroup analysis was also performed for specific variables of interest. Twenty-seven (25%) participants applied the target cricoid force. Of the 80 participants who were outside of the target range, 50 (63%) applied less than the target range and 30 (37%) applied more than the target range. No statistically significant difference was demonstrated for sex, age, qualification or years of experience and the ability to apply cricoid force within the target range. More candidates (27) applied the target range than those who correctly identified it (12). When methods of instruction were compared there was no difference between candidates with one and more than one modality of instruction (t-test: t (105) = -0.09, P = 0.9; 95% confidence interval [CI]-0.66-0.6) and the mean cricoid force applied. Those who had greater than one form of instruction applied correct cricoid force at the target range more often than those who had received only one form of instruction, this result was significant. (chi(2) = 4.24, d.f. = 1, P = 0.04; odds ratio = 2.6; 95% CI 1.03-6.41). The application of cricoid force by ED staff participating in the present study is unreliable, often providing inadequate protection against regurgitation. Training using a model integrating the concept of force is recommended. The role of cricoid pressure in rapid sequence induction needs to be further investigated.

Cricoid pressure: a simple, yet effective biofeedback trainer

Background and objective: Only regular training of anaesthetic personnel ensures safe and reliable application of cricoid pressure during rapid sequence induction of anaesthesia. Previously described training devices are either complicated, too expensive and usually unavailable, or they are very simple and do not correctly simulate the process of applying cricoid force. We designed and tested a cricoid pressure trainer with real-time display of applied force. The device is easy to assemble at relatively little cost with material widely available. It allows effective biofeedback training of the force required during the Sellick manoeuvre and can be used for routine staff assessment. Methods: Thirty-six anaesthesia assistants were assessed for their correct application of cricoid pressure. Previous training in, and knowledge of, applying cricoid pressure was first evaluated by a questionnaire. We designed a model for testing the application of cricoid force. Pre-training cricoid forces were obtained by asking the subjects to apply 'awake' (10 N = 1.020 kg) and 'asleep' (30 N = 3.060 kg) cricoid pressure on our model while blinded to the actual pressure produced. The volunteer was then trained to apply correct pressure employing real-time biofeedback. Post-training values were later determined with the subject again blinded to the actual applied pressure. Results: Post-training performance showed significant improvement in the application of the correct cricoid force (P < 0.0005). Only 8% (3/36) of subjects applied incorrect 'awake' cricoid pressure after training vs. 56% (20/36) before training. All participants applied correct 'asleep' cricoid pressure after training vs. 72% (26/36) failing before training. Conclusions: Our biofeedback cricoid pressure trainer is effective in the assessment and training of correct cricoid pressure application by anaesthetic personnel.

Cricoid pressure: a simple, yet effective biofeedback trainer.

Only regular training of anaesthetic personnel ensures safe and reliable application of cricoid pressure during rapid sequence induction of anaesthesia. Previously described training devices are either complicated, too expensive and usually unavailable, or they are very simple and do not correctly simulate the process of applying cricoid force. We designed and tested a cricoid pressure trainer with real-time display of applied force. The device is easy to assemble at relatively little cost with material widely available. It allows effective biofeedback training of the force required during the Sellick manoeuvre and can be used for routine staff assessment. Thirty-six anaesthesia assistants were assessed for their correct application of cricoid pressure. Previous training in, and knowledge of, applying cricoid pressure was first evaluated by a questionnaire. We designed a model for testing the application of cricoid force. Pre-training cricoid forces were obtained by asking the subjects to apply 'awake' (10 N = 1.020 kg) and 'asleep' (30 N = 3.060 kg) cricoid pressure on our model while blinded to the actual pressure produced. The volunteer was then trained to apply correct pressure employing real-time biofeedback. Post-training values were later determined with the subject again blinded to the actual applied pressure. Post-training performance showed significant improvement in the application of the correct cricoid force (P < 0.0005). Only 8% (3/36) of subjects applied incorrect 'awake' cricoid pressure after training vs. 56% (20/36) before training. All participants applied correct 'asleep' cricoid pressure after training vs. 72% (26/36) failing before training. Our biofeedback cricoid pressure trainer is effective in the assessment and training of correct cricoid pressure application by anaesthetic personnel.