Optimum LMA cuff pressure

Slater, Paul V.; Lavies, N.G.

doi:10.1111/j.1365-2044.1996.tb15074.x

Cited by 7 publications

(8 citation statements)

References 5 publications

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“…Intracuff pressures as low as 30 cmH 2 O have been used in spontaneously breathing patients [18], but such low pressures may be inadequate for positive pressure ventilation [11]. We have also confirmed previous interpatient data that volumes of Ϸ 4-14 ml are all that is required to obtain an intracuff pressure of 60 cmH 2 O [8] and shown that these volumes are similar for all three sizes. At low cuff volumes, the LMA cuff is soft and intracuff pressure is primarily a function of pharyngeal anatomy and pharyngeal muscle tension, rather than the elastance of the silicone cuff.…”

Section: Discussionsupporting

confidence: 76%

“…The manufacturer currently recommends low intracuff pressures with the aim of reducing pharyngeal morbidity [1]. There is evidence that the use of low cuff volume/low intracuff pressure reduces the incidence of sore throat and/ or emergence complications [8,9], although this has recently been questioned [16]. There is no correlation between the size of mask chosen and the incidence of sore throat at low cuff pressures [17].…”

Section: Discussionmentioning

confidence: 99%

“…The complexity of these relationships has been highlighted by a recent study which suggested a correlation between increasing body mass index and decreasing pharyngeal height [15]. The 1998, 53, 565-570 ........................................................................................................................................................................................................................................... (n 30) 25 (9, 33 (8, 27 (10, implication is that obese patients require smaller masks, but the relevance of pharyngeal height (tip of epiglottis to posterior edge of pharyngeal opening) to pharyngeal sac anatomy (where the LMA sits) is unknown. The size 5 and 4 LMAs are more suitable for adults than the size 3 at intracuff pressures of 60 cmH 2 O.…”

Section: Discussionmentioning

confidence: 99%

“…Common current practice is to inflate the LMA cuff to near-maximum recommended volumes (20-40 ml) [4,5]. It is now suggested that a cuff pressure of 60 cmH 2 O is more appropriate [7,8], because this may reduce the incidence of pharyngeal morbidity [8][9][10][11].…”

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confidence: 99%

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An evaluation of the factors influencing selection of the optimal size of laryngeal mask airway in normal adults

et al. 1998

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SummaryThe purpose of this randomised single blinded study was to determine the optimal size of laryngeal mask airway in the normal adult population, to test the validity of the current selection criteria and to determine if any externally measured anatomical variable correlated with optimal size. In each of 30 apnoeic anaesthetised adults weighing less than 100 kg, size 3, 4 and 5 laryngeal mask airways were inserted in random order by a skilled user and the cuff inflated to a standard pressure (60 cmH 2 O). Optimal size was based on four criteria in order of priority: number of attempts at placement, oropharyngeal leak pressure, fibreoptic score and percentage of vocal cords seen. The size 5 laryngeal mask airway was optimal in 19/30 and the size 4 in 11/30. In no patient was the size 3 the optimal fit. Oropharyngeal leak pressure was significantly higher for each progressively larger size and the fibreoptic view was significantly better for the size 4 and size 5. There was no significant predictive value in any externally measured anatomical variable, but height was the most useful. The best current selection strategy was to choose a size 5 for males and size 4 for females. Potentially useful new strategies may be to use the size 5 in all adults, or a size 5 Ն 165 cm in height and size 4 for`165 cm. We conclude that predicting the optimal size of laryngeal mask airway for individual adult patients is complex. The best size selection strategies involve use of the size 4 and 5 laryngeal mask airways in adults.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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An evaluation of the factors influencing selection of the optimal size of laryngeal mask airway in normal adults

et al. 1998

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“…Unfortunately, the volume of gas in the cuff increases when raised from room to body temperature and increases further by inward diffusion of nitrous oxide [10] and the measurement of volumes removed are not exact. If the volume cannot increase, pressure rises and may reach 120 cmH 2 O within 20–30 min [11]. Pressure within the cuff is not necessarily the same as the pressure of the cuff wall on surrounding structures.…”

Section: Introductionmentioning

confidence: 99%