Cricopharyngeal myotomy in motor neurone disease.
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Twenty-five patients with dysphagia caused by neurological disorders, mainly motor heurone disease, underwent cricopharyngeal myotomy. Nineteen patients showed slight to dramatic improvement of swallowing for variable periods of time. There were five postoperative deaths. The results indicate that this simple procedure is of benefit to a substantial proportion of patients with neurological causes of dysphagia. (+info)
Cricoid pressure impedes placement of the laryngeal mask airway.
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We have studied 22 patients to examine whether or not cricoid pressure affects ventilation of the lungs via the laryngeal mask and its correct positioning. In a randomized, crossover design, the laryngeal mask was inserted with or without cricoid pressure applied with a standardized force of 30 N using a cricoid yoke. A standardized pillow (6 cm in height) was placed under the patient's occiput, but the neck was not supported. Ventilation of the lungs via the laryngeal mask was adequate in all patients when no cricoid pressure was applied, but in only three of 22 patients when cricoid pressure was applied (P << 0.001; 95% confidence interval (CI) 0.72-1.0). The mask was positioned correctly in 18 patients when no pressure was applied, and in none after application of cricoid pressure (P << 0.001; 95% CI 0.66-0.98). We had planned to study, in an additional 20 patients, the effect of cricoid pressure without a pillow under the occiput; placement of the mask, however, was difficult even when cricoid pressure was not applied and there was a high incidence of bleeding from the oropharynx. We thus abandoned that part of the study after eight patients. In those eight patients, the success rate of ventilation via the laryngeal mask was lower when cricoid pressure was applied. We conclude that when sufficient force was applied, cricoid pressure, regardless of the method of application, did impede placement of the laryngeal mask. (+info)
Equine cricoid cartilage densitometry.
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The density of the cricoid cartilage from 29 equine larynges collected from an abattoir was determined by dual photon absorptiometry (DPA). Densities of the right and left cricoid cartilages were highly correlated. No correlation was found between age of the horse and the density of the cricoid cartilage. (+info)
The effect of cricoid pressure on preventing gastric insufflation in infants and children.
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BACKGROUND: The use of cricoid pressure for the possible prevention of regurgitation of gastric contents during induction of anesthesia in both adults and children has been recommended. However, equally important is the technique in possibly preventing insufflation of gas into the stomach. This study was designed to determine the efficacy of cricoid pressure application in preventing gastric gas insufflation in pediatric patients and to determine the airway pressure at which gas entered the stomach (pop-off point). METHODS: Fifty-nine patients, 2 weeks to 8 yr of age, physical status 1-4, scheduled for elective surgery, received an inhalational induction of anesthesia with halothane, N2O, and O2. A single observer used a stethoscope to auscultate over the upper abdomen for any air entry. In study I (without paralysis), the proximal airway pressure was slowly increased by gradually closing the pop-off valve on the anesthesia machine until gas was heard entering the stomach (pop-off point) or until the peak inspiratory pressure (PIP) reached 40 cm H2O. Thereafter, the pressurization procedure was repeated three times, altering the application and removal of cricoid pressure. The same patients were then paralyzed (study II), and the stomach evacuated before commencing an identical pressurization sequence with and without cricoid pressure. RESULTS: Appropriately applied cricoid pressure was 100% effective in preventing gas insufflation into the stomach of all children up to 40 cm H2O PIP with and without paralysis. In addition, paralysis significantly decreased the median pop-off point in any given patient. CONCLUSIONS: Appropriate application of cricoid pressure prevents gastric gas insufflation during airway management via mask up to 40 cm H2O PIP in infants and children. An additional benefit of cricoid pressure occurs in paralyzed patients in whom gastric insufflation occurs at lower inflation pressures. (+info)
Cricoid pressure applied after placement of the laryngeal mask prevents gastric insufflation but inhibits ventilation.
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We studied 50 patients, in a blind, crossover study, to assess if cricoid pressure applied after placement of the laryngeal mask prevented gastric insufflation without affecting ventilation. After induction of anaesthesia and neuromuscular block, a laryngeal mask was inserted and confirmed to be placed correctly. The lungs were ventilated with a maximum inflation pressure of 15 cm H2O. In the first 25 patients, expiratory volumes were measured with and without cricoid pressure (30 N). On both occasions, a free hand was placed under the patient's neck. In the next 25 patients, the effect of cricoid pressure on ventilation without support of the neck was also studied. The effect of cricoid pressure with support of the neck on gastric insufflation was then assessed using a stethoscope in all 50 patients, while the lungs were ventilated with a maximum inflation pressure of 30 cm H2O. At the end of the study, the position of the mask was re-assessed. Cricoid pressure significantly decreased mean expiratory volume (P << 0.001). This inhibitory effect was significantly greater when the pressure was applied without support of the neck (P << 0.001). Cricoid pressure significantly reduced the incidence of gastric insufflation (12 patients vs one patient; P << 0.001; 95% CI for difference 10.5-33.5%). In no patient was the mask dislodged after these procedures. Thus, although cricoid pressure applied after insertion of the laryngeal mask prevented gastric insufflation, it also decreased ventilation. The inhibitory effect of cricoid pressure on ventilation without support of the neck was greater than cricoid pressure with support of the neck. (+info)
Fracture of the cricoid cartilage after Sellick's manoeuvre.
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We report a case of fracture of the cricoid cartilage associated with cricoid pressure during rapid sequence tracheal intubation in a patient with status asthmaticus. This patient had a history of laryngeal trauma 48 yr previously. Fracture of the cricoid cartilage has not been reported previously after cricoid pressure. (+info)
Use of a mechanical simulator for training in applying cricoid pressure.
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Using an airway management training model, we have assessed anaesthesia personnel in their use of correct cricoid force and ability to retain this skill after a short training programme. A perspex device, working on a hydraulic principle, was used to measure cricoid pressure when applied to the model. After initial assessment at two levels of cricoid force (20 and 40 N), participants undertook additional training on 3 consecutive days. Thereafter, available participants underwent reassessment at 14-21 days. Forty-nine anaesthetic assistants and anaesthetists underwent initial assessment and 18 completed the full training and reassessment. Untrained, the majority (63%) of participants applied inadequate cricoid force with a wide variation (mean 16.8 (SD 9.3) (range 4.5-43.0) at 20 N and 32.9 (13.3) (14.9-74) at 40 N). After a single training session there was a marked improvement in application of cricoid force. Two additional training sessions did not provide further improvement. After 14-21 days the ability of participants to apply correct cricoid force was retained by 72% of subjects. Those who applied inadequate cricoid force initially were more likely to do so even after training. Most subjects applied too great a cricoid force in the first 5 s of application followed by a progressive loss of force during the next 20 s. This trend improved after training. We conclude that the majority of untrained personnel apply inadequate cricoid force, placing patients at risk of aspiration of gastric contents. While a simple training programme improved application of cricoid force, retained for up to 3 weeks, there was often a substantial decrease in the force applied to the cricoid during a single application, even after training. (+info)
BACKGROUND: Cricoid cartilage pressure induced to prevent pulmonary aspiration from regurgitation of gastric contents has been recommended, and its efficacy requires a force greater than 40 Newtons. For regurgitation to occur, both an increase in gastric pressure and relaxation of the lower esophageal sphincter (LES) are necessary. However, the effect of cricoid cartilage pressure on the LES is unknown. This study evaluated the effects of cricoid cartilage pressure on LES in human volunteers. METHODS: Lower esophageal sphincter and esophageal barrier pressures (which equals LES pressure-gastric pressure) were measured using a manometric method in eight unanesthetized volunteers (4 men, 4 women) classified as American Society of Anesthesiologists physical status 1. The force applied to the cricoid cartilage was measured continuously, and LES pressure was recorded at a cricoid force of 20 and 40 Newtons. RESULTS: Cricoid pressure decreased LES pressure from 24 +/- 3 mmHg to 15 +/- 4 mmHg at a force of 20 Newtons (P < 0.05) and to 12 +/- 4 mmHg with a force of 40 Newtons (P < 0.01). CONCLUSIONS: These findings may explain the occurrence of pulmonary aspiration before tracheal intubation despite application of cricoid cartilage pressure. (+info)