The Elimination of Rebreathing in Various Semi-Closed Anaesthetic Systems

Mapleson, W.W.

doi:10.1093/bja/26.5.323

Cited by 224 publications

(104 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In both experiments 1 and 2 the plot of predicted and observed results strongly resembles that predicted by Mapleson [5]. Rebreathing is eliminated with a fresh gas flow of approximately 0.8 x total ventilation, which agrees with the results of Ooi and colleagues [6].…”

Section: Prcdictetl Und Esperimentul Resultssupporting

confidence: 86%

See 1 more Smart Citation

The importance of the expiratory pause

Cook

1996

Anaesthesia

View full text Add to dashboard Cite

SummaryA physical lung model simulating spontaneous respiration was used to investigate the influence of the respiratory pattern on the eficiency of the Mapleson A , C and D breathing systems. It is shown that the Mapleson A system is always the most efficient breathing system and that its performance is relatively independent of the respiratory pattern. When the expiratory pause is minimal, the Mapleson C systetn is almost as eficient as the Mapleson A , hut hecomes ever less eficient as the expiratory pause increases. The Mapleson D svstern is very ineficient when the expiratory pause is short. With a longer expiratory pause, this sys f em's eficiency approaches that qf the Mapleson A . The e.xperiniental results are compared with predictions generated by a niathetnutical niodel. There is good agreement between the two, oalidating the mathematics used. Key wordsEquipment; breathing systems, Mapleson ACD, lung model.A previous paper offered a theoretical analysis of the influence of the respiratory pattern on the efficiency of the Mapleson A, C and D breathing systems [I]. The analysis suggested that the principal determinant of the efficiency of the Mapleson C and D breathing systems is the length of the expiratory pause. A longer pause should render the C system less efficient and the D system more efficient.In this investigation, a physical lung model which simulates spontaneous respiration [2] was used to test these predictions. The effect of various changes in the respiratory pattern on the performance of the Mapleson A, C and D breathing systems was examined. For each case the respiratory pattern used was also analysed using the equations previously presented [I], allowing comparison between the predicted and actual results.As in the companion papers [I, 21, rebreathing is quantified as an increase in the ratio of deadspace ( V D ) to tidal volume ( VT), as described by Jaeger and Schultetus [3]. The physical deadspace within the model is designated VDpat and the total deadspace (including that added by the breathing system) is designated VDlOt. MethodThe model simulates spontaneous respiration and has been described previously [2]. It allows direct measurement of rebreathing in terms of VDtof/VT ratios for each breathing system. Briefly, the lung is represented by a bellows which is made to move via a mechanical link to a second, ventilated bellows. The deadspace is represented by corrugated tubing, a 9 mm ID tracheal tube (Portex) and a catheter mount. The inspired tidal volume is diverted through a gas splitter which allows the mean carbon dioxide concentration inspired into the 'alveoli' to be measured. The ratio of mean inspired to end-tidal (i.e. alveolar) carbon dioxide is the VDtOt/VT ratio. The respiratory pattern may be varied by altering the settings of the ventilator driving the model and/or the resistances in the ventilator circuit.The model was used to compare the Mapleson A, C and D breathing systems. In all experiments the respiratory rate was 10 breath.min-I, the tidal volume was kept con...

show abstract

Section: Prcdictetl Und Esperimentul Resultssupporting

confidence: 86%

“…Similarly, if there were no gas mixing the plot of observed results should follow that of the predictions until the latter intercepts line NBS (no breathing system), after which the observed results should follow line NBS. In reality this transition is slurred, because of gas mixing [5].…”

Section: Tep/resp Cyclementioning

confidence: 99%

The importance of the expiratory pause

Cook

1996

Anaesthesia

View full text Add to dashboard Cite

show abstract

“…5 With the Mapleson A system, the FGF is delivered distally near the reservoir bag, while the overflow valve is located proximally near the patient end of the system, which decreases the degree of rebreathing. In contrast, with the Mapleson D system, the FGF is delivered proximal to the patient, while the outlet valve is distally located near the reservoir bag, which increases the possibility of rebreathing.…”

Section: Resultsmentioning

confidence: 99%

“…5 Such differences in the degree of rebreathing may affect the efficacy of preoxygenation. This study was designed to investigate the hypothesis that oxygen flow and anesthetic system type may influence the efficacy of preoxygenation.…”

Section: Discussionmentioning

confidence: 99%

Preoxygenation with the Mapleson D system requires higher oxygen flows than Mapleson A or circle systems

Taha

El-Khatib

Siddik-Sayyid

et al. 2007

Can J Anesth/J Can Anesth

View full text Add to dashboard Cite

“…A Mapleson F anaesthetic breathing system (Ayre's T-piece with Jackson-Rees modification) should be used in children weighing less than 25 kg as it offers least resistance to expiration [5].…”

mentioning

confidence: 99%

The effect of a heat and moisture exchanger on gas flow in a Mapleson F breathing system during inhalational induction

Fonseca¹,

Wheeler

Pook

2000

Anaesthesia

View full text Add to dashboard Cite

SummaryHeat and moisture exchangers (HMEs) humidify, warm and filter inspired gas, protecting patients and apparatus during anaesthesia. Their incorporation into paediatric anaesthetic breathing systems is recommended. We experienced delays in inhalational induction whilst using a Mapleson F breathing system with an HME. We have demonstrated that the HME significantly alters gas flow within the breathing system. Approximately half of the fresh gas flow is delivered to the patient, the remainder being wasted into the expiratory limb of the breathing system. We suggest that the HME should be removed from the Mapleson F breathing system until inhalational induction is complete, or that the reservoir bag is completely occluded until an effective seal is obtained with the mask.

show abstract

The Elimination of Rebreathing in Various Semi-Closed Anaesthetic Systems

Cited by 224 publications

References 0 publications

The importance of the expiratory pause

The importance of the expiratory pause

Preoxygenation with the Mapleson D system requires higher oxygen flows than Mapleson A or circle systems

The effect of a heat and moisture exchanger on gas flow in a Mapleson F breathing system during inhalational induction

Contact Info

Product

Resources

About