Cricoid pressure impedes placement of the laryngeal mask airway

Abstract

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.

Cricoid pressure impedes positioning and ventilation through the laryngeal mask airway

“…In the recent study reported by Asai et al, even single-handed cricoid pressure impeded placement of the LMA when sufficient force was applied. 12 These findings indicate that cricoid pressure should not be used during insertion of the LMA. In some patients, adequate ventilation can be obtained through the LMA during cricoid pressure.…”

Ease of tracheal intubation through the intubating laryngeal mask during manual in‐line head and neck stabilisation

“…This is a well-recognised cause of a decrease in temperature following anaesthetic induction [12]. Indeed, the only way that this decrease in core temperature may be avoided is by a period of active warming pre-induction [9,13].…”

“…This is a well-recognised cause of a decrease in temperature following anaesthetic induction [12]. Indeed, the only way that this decrease in core temperature may be avoided is by a period of active warming pre-induction [9,13].We have shown that there is a significant decrease in patients' core temperature in the anaesthetic room while intravascular lines, epidural and urinary catheters are inserted. To reduce this temperature decrease, lines and catheters should be placed before induction of general anaesthesia.…”

Compressão da cartilagem cricóide: aspectos atuais

“…A prevenção da aspiração pulmonar é fundamental, mas a permeabilidade das vias aéreas deve prevalecer. A ventilação e a oxigenação podem ser facilitadas pelo emprego da máscara laríngea convencional ou da ProSeal ® , mas, de acordo com alguns estudos, a manobra de Sellick dificulta o correto posicionamento de ambos os instrumentos de acesso à via aérea 38,39 . Nesses casos, pode ser necessária a interrupção da manobra temporariamente, o que parece ser uma opção razoável, já que a compressão da cartilagem cricóide pode se tornar ineficaz após poucos minutos de aplicação 40 .…”