Rebreathing in a T-Piece: Volunteer and Theoretical Studies of the Jackson-Rees Modification of Ayre's T-Piece During Spontaneous Respiration

Willis, B.A.; PENDER, JOHN W.; Mapleson, W.W.

doi:10.1093/bja/47.12.1239

Cited by 51 publications

(16 citation statements)

References 4 publications

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“…In the Mapleson D system the VD/VT ratio has been considered to have less influence on the degree of rebreathing. The small effects noted in this study support this view and are in line with the results presented by Willis et al (17).…”

Section: Discussionsupporting

confidence: 94%

Fresh gas flow in coaxial Mapleson A and D circuits during spontaneous breathing

Jönsson

Zetterström

1986

Acta Anaesthesiol Scand

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In a lung model simulating spontaneously breathing halothane anaesthesia, the rebreathing characteristics of the coaxial Mapleson A (Lack circuit) and D (Bain circuit) systems were tested. Using decreasing fresh gas flows (VF), the end-tidal carbon dioxide fraction (FACO2) was monitored and the point of rebreathing (R.P.) detected. The effects of changes in minute volume (VE), dead-space to tidal volume ratio (VD/VT) and carbon dioxide elimination (VCO2) were studied. The effect of increased tidal volumes (VT) on FACO2 was investigated for some different fresh gas flows (VF). The VF/VE ratio for R.P. in the Bain circuit was approximately 2 and in the Lack circuit 0.88. In both circuits an increase in VE and a decrease in the VD/VT ratio resulted in higher demands on VF if rebreathing was to be avoided. The latter effect was much more pronounced in the Lack circuit. In neither system did any changes in VCO2 affect the rebreathing characteristics. The conclusion was drawn that the Lack system is a much better choice concerning the fresh gas flows for anaesthesia with spontaneous breathing than the Bain system. It was also concluded that the fresh gas flows recommended by Humphrey for the Lack system (i.e. 51 ml X min-1 X kg b.w.-1) and by the manufacturers for the Bain system (i.e. 100 ml X min-1 X kg b.w.-1) are inadequate and should be increased if a considerable degree of rebreathing is to be avoided.

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Section: Discussionsupporting

confidence: 94%

Fresh gas flow in coaxial Mapleson A and D circuits during spontaneous breathing

Jönsson

Zetterström

1986

Acta Anaesthesiol Scand

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“…The high fresh gas flow used in our method not only ensures that expired gas does not escape past leaks at the rim of the mask (Evans et al, 1977) but also ensures that rebreathing of expired gas does not occur. At gas flows of less than twice the minute volume, rebreathing is likely to occur (Willis et al, 1975). Assuming, in the neonate, a minute volume of 300 ml/kg per min the fresh gas flow should therefore exceed 600 ml/kg per min.…”

Section: Discussionmentioning

confidence: 99%

Simple and versatile method for measuring oxygen consumption in infants.

Evans¹,

Gray²,

Holland³

et al. 1978

Archives of Disease in Childhood

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SUMMARY A simple, rapid, and accurate method for measuring oxygen consumption in infants is described. Expired gas is entrained in a stream of air drawn through a gently applied face mask. Oxygen consumption is derived from (1) gas flow rate, measured with a flowmeter, and (2) the fall in oxygen concentration of the gas mixture, measured with a paramagnetic analyser. A measurement can be made at the bedside within 2 minutes without disturbing the infant. In 17 mature 2-day-old neonates mean oxygen consumption was 6 52 ml/kg per min, SD 0 90, similar to that previously reported using less simple methods.

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“…In Method 2, we produced a Mapleson F system by modifying the Mapleson E in Method 1 5,6 . Using the reservoir bag from the circle system, we cut off the tip of the bag, and attached it to the 'machine' end of the expiratory tube, distal to the microbial filter (Figures 2A and 2B).…”

Section: Methodsmentioning

confidence: 99%

Potential Rapid Solutions to Maintain Ventilation in the Event of Anaesthesia Machine Failure with no Access to the Patient's Airway

Liu

Tan

Loh

et al. 2016

Anaesth Intensive Care

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Anaesthesia machine failure requires rapid solutions to maintain ventilation and anaesthesia. During procedures with poor access to the patient's airway, it may not be possible to use a self-inflating mechanical ventilation device (SIMVD) for emergency ventilation, and alternative solutions are needed. We evaluated five methods for rescue ventilation using a patient simulator. In Method 1, we used the inspiratory and expiratory tubes and the alternative common gas outlet (ACGO) on the anaesthesia machine to produce a Mapleson E system. In Method 2, we used the tubes, ACGO and an open-ended reservoir bag to produce a Mapleson F system, controlling the bag to achieve ventilation. In Method 3, we attached a SIMVD to the inspiratory tube, and controlled occlusion of the expiratory tube. In Method 4, we used the tubes and ACGO in a Mapleson F configuration, replacing the open-ended bag with a SIMVD to facilitate manual ventilation. In Method 5, we attached a SIMVD to the expiratory tube and left the inspiratory tube attached to its mounting. We were able to achieve ventilation, maintain inhalational anaesthesia, and prevent expired gas rebreathing in Methods 1 and 2. In Method 3 ventilation was achieved with minimal rebreathing of expiratory gas, but with no inhalational agent. Methods 4 and 5 led to rebreathing. Our findings indicate that Methods 1 or 2 are the preferred rapid solutions to maintain ventilation and inhalational anaesthesia in the event of anaesthesia machine failure where there is poor airway access.

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Rebreathing in a T-Piece: Volunteer and Theoretical Studies of the Jackson-Rees Modification of Ayre's T-Piece During Spontaneous Respiration

Cited by 51 publications

References 4 publications

Fresh gas flow in coaxial Mapleson A and D circuits during spontaneous breathing

Fresh gas flow in coaxial Mapleson A and D circuits during spontaneous breathing

Simple and versatile method for measuring oxygen consumption in infants.

Potential Rapid Solutions to Maintain Ventilation in the Event of Anaesthesia Machine Failure with no Access to the Patient's Airway

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