Upper oesophageal sphincter pressure and the effect of cricoid pressure

Vanner, R. G.; O'dwyer, J. P.; Pryle, B. J.; Reynolds, F.

doi:10.1111/j.1365-2044.1992.tb02001.x

Cited by 125 publications

(75 citation statements)

References 28 publications

(14 reference statements)

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“…The upper esophageal sphincter may not be important in preventing gastro-oesophageal insufflation. 21 We can offer two possible explanations for our findings. First, the face mask technique requires the anaesthetist to seal the mask against the skin of the face.…”

Section: Resultsmentioning

confidence: 85%

Gas leak and gastric insufflation during controlled ventilation: face maskversus laryngeal mask airway

et al. 1998

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R~.TPurpose: To compare two airway management techniques, face mask (FM) with oropharyngeal airway and laryngeal mask airway (LMA), with respect to the effectiveness of positive pressure ventilation and airway maintenance. Methods: After induction of anaesthesia, two airway management techniques (FM or LMA) and three peak pressures (20, 25 and 30 cm H20 ) were randomly applied during controlled ventilation in 60 patients. Data collected included inspiratory and expiratory volumes and presence of gastro-oesophageal ins~ation. Leak was calculated by subtracting the expiratory from the inspiratory volume, expressed as a fraction of the inspiratory volume. Results: Expiratory volumes (mean _+ SD) at 20, 25 and 30 cm H20 for LMA ventilation were 893 _+ 260, 986 -+ 276 and 1006 +_ 262 respectively, and for FM ventilation 964 + 264, I 100 + 268 and I 116 + 261. Leak fractions at 20, 25 and 30 cm H20 for LMA ventilation were 0.21 + 0.15, 0.24 _+ 0.18 and 0.26 -+ 0.18 respectively, and for FM ventilation 0.14 _+ 0.09, 0.14 _+ 0.09 and 0. 12 _+ 0.08. The frequency of gastro-oesophageal insuft]ation was 1.6%, 5% and 5% for the LMA and 5%, 15% and 26.6% for the FM for ventilation pressures of 20, 25 and 30 cm H20 respectively which was greater with LMA use. Conclusion: Ventilation was adequate in all patients using both techniques. Leak was pressure dependent and greater with LMA use. Most of the leak was vented to the atmosphere via the pharynx. Gastro-oesophage~ insufflation was more frequent with ventilation using the face mask. LMA use with positive pressure ventilation would appear to be a better airway management method than the face mask. Conclusion : La ventilation a 6t6 ad6quate chez tousles patients en utilisant l'une ou rautre technique. La fuite &air plus grande avec le ML, d6pendait de la pression et &alt en grande pattie 6vacu6e dans ratmosph&e par le pharynx. l'insufl]ation gastro-oesophagienne Etait plus frEquente avec I'utilisation du ME ILutilisation du ML Iors de ventilation pression positive semble une meilleure m~thode de maintien des voies a&iennes que I'utilisation du masque facial.

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Section: Resultsmentioning

confidence: 85%

Gas leak and gastric insufflation during controlled ventilation: face maskversus laryngeal mask airway

et al. 1998

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“…We previously reported that in anaesthetised and paralysed patients a cricoid force of 40 Newtons increased UOSP to above the median of the awake values in all patients [5]. This level of cricoid pressure is uncomfortable and vomiting has followed its application resulting in death from aspiration pneumonitis in one patient [33], and rupture of the oesophagus in another [34].…”

Section: Discussionmentioning

confidence: 99%

“…The upper oesophageal sphincter can also prevent the regurgitation of oesophageal contents during light general anaesthesia in the absence of neuromuscular blockade [2, 31. Suxamethonium usually causes an abrupt fall in upper oesophageal sphincter pressure (UOSP) with the onset of fasciculations [4]. In those patients at risk of gastro-oesophageal reflux, cricoid pressure counteracts this reduction in UOSP [5]. However, there is controversy about when cricoid pressure should be applied: before loss of consciousness [6, 71, or only after loss of consciousness [8,9] in case vomiting is provoked by its application.…”

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confidence: 99%

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Upper oesophageal sphincter pressure and the intravenous induction of anaesthesia

et al. 1992

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SummaryThe upper oesophageal sphincter can prevent regurgitation of oesophageal contents into the pharynx following gastrooesophageal rejux in the awake patient. Upper oesophageal sphincter pressure was recorded with a Dent sleeve after hypnosis with midazolam (n = 7 ) and also during the rapid intravenous induction of anaesthesia with thiopentone ( n = 16) or ketamine (n = 7 ) . Thiopentone decreased mean(SD) sphincter pressure from an awake value of 43(19) to 9 ( 7 ) mmHg ( p < 0.001) and midazolam from 38(25) to 7 ( 3 ) mmHg ( p < 0.02). Mean(SD) sphincter pressures before and after ketamine were not significantly diflerent at 29( I S ) and 32(2I) mmHg respectively. After suxamethonium mean( S D ) sphincter pressure in all patients (n = 30) was 7 ( 4 ) mmHg. Laryngoscopy (n = 30) caused a small increase in meanlSD) sphincter pressure to 13(10) mmHg ( p < 0,001). Thiopentone caused a rapid fall in upper oesophageal sphincter pressure which usually started before loss of consciousness. These findings have implications for the timing of cricoid pressure application.

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“…Nor is cricoid pressure itself entirely straightforward, even trained staff do not consistently apply it correctly [2,3]. Cricoid pressure may also make ventilation harder, paradoxically increasing the likelihood of gastric insufflation.…”

Section: Swindon Wiltshire Sn1 4jumentioning

confidence: 99%

Cricoid pressure and advance life support

Smurthwaite

1995

Anaesthesia

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Upper oesophageal sphincter pressure and the effect of cricoid pressure

Cited by 125 publications

References 28 publications

Gas leak and gastric insufflation during controlled ventilation: face maskversus laryngeal mask airway

Gas leak and gastric insufflation during controlled ventilation: face maskversus laryngeal mask airway

Upper oesophageal sphincter pressure and the intravenous induction of anaesthesia

Cricoid pressure and advance life support

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