A comparison of anaesthetic breathing systems during spontaneous ventilation

Chan, A.; Bruce, W. E.; Soni, Neil

doi:10.1111/j.1365-2044.1989.tb11221.x

Cited by 23 publications

(3 citation statements)

References 24 publications

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“…The fractional utilization curve shown in figure 2 is similar to that obtained by Rose and Froese using a Bain system [12], and that obtained by Snowdon and colleagues using one of two circle systems without an absorber with a tidal volume of 750 ml [10]. This suggests that, although there are well-documented advantages of the EAR during spontaneous ventilation [13,14], there may be little difference in clinical efficiency between the above systems during controlled ventilation. This agrees with the work of Criswell and colleagues, who found only a small difference in PE' COI values in patients during ventilation with an EAR system and the Bain (0.35 kPa), and concluded that they were of similar clinical efficiency [15].…”

Section: Discussionsupporting

confidence: 79%

Efficiency of an Enclosed Afferent Reservoir Breathing System During Controlled Ventilation

Droppert

Meakin

Beatty

et al. 1991

British Journal of Anaesthesia

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We describe an enclosed afferent reservoir (EAR) breathing system developed by Ohmeda and designed to operate efficiently in spontaneous and controlled ventilation. The efficiency of the system was evaluated by calculating the fractional utilization of fresh gas in 10 ASA I-III patients during anaesthesia with controlled ventilation. Maximum efficiency occurred when the minute ventilation to fresh gas flow ratio was greater than 1.5. Under these conditions, fractional utilization was relatively constant with a value of 0.73 (95% confidence interval 0.69-0.78). The minimum fresh gas flow for use during controlled ventilation was determined in another eight ASA I-III patients when the minute volume to fresh gas ratio was greater than 1.5. In view of an increased arterial to end-tidal carbon dioxide partial pressure difference in patients in the first part of the study (1.03 kPa), normocapnia was defined as an end-tidal carbon dioxide partial pressure of 4.3 kPa. Normocapnia was achieved with a mean fresh gas flow of 66 ml kg(-1) min(-1), while 70 ml kg(-1) min(-1) produced mild hypocapnia.

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Section: Discussionsupporting

confidence: 79%

Efficiency of an Enclosed Afferent Reservoir Breathing System During Controlled Ventilation

Droppert

Meakin

Beatty

et al. 1991

British Journal of Anaesthesia

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“…Bain system demonstrated rebreathing even at considerably higher fresh gas flows. 14 In this study an effective EtCO2 level of 28.230.99 mm of Hg. Could be maintain using the Circle absorber system with a fixed fresh gas flow of 4.5 litres and the average FiCO2 level was in the order of 0.390.07%.…”

Section: Discussionmentioning

confidence: 70%

A Clinical Comparative Study to Ascertain Efficacy of Circle Absorption System and Bain Breathing System in Maintaining Effective Hypocapnia During Intracranial Surgery

Choudhury¹

2015

jemds

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AIM OF THE STUDY:To ascertain efficacy of the Circle absorption system and the Bain breathing system in maintaining effective hypocapnia to create a favorable environment for smooth conduct of intracranial surgery, with the help of Capnographic monitoring. MATERIALS AND METHODS: In the study fifty adult patients of ASA-I or II physical status requiring intracranial surgeries under General Anesthesia were selected irrespective of sex and randomly allocated in two groups. In one Group the Circle absorption system and in another Group the Bain breathing system was used for delivery of the anesthetics and performance of IPPV. To avoid variation in observations same premedications, anaesthetic drugs and anaesthetic technique excepting the breathing system varying as per group were used in all the patients of both the groups. Circle absorption system was used with a fresh gas flow of 4.5 Liters and Bain breathing system was used with a fresh gas flow of 6 Liters for maintenance of anaesthesia and performance of IPPV. Pulse rate, SpO2, SBP, DBP and MAP were recorded before induction of Anaesthesia, during induction, after intubation, at the time of incision and every 10mins thereafter till the time of reversal. EtCO2 and FiCO2 were recorded immediately after intubation, at the time of incision and every 10mins thereafter till the time of reversal. Desired level of EtCO2 was maintained by moderate hyperventilation as and when required. Brain relaxation was graded in consultation with the surgeon and by simple visual assessment. RESULTS AND OBSERVATIONS:The study involved analysis of capnometric information acquired following use of both the breathing systems. The ability of both the breathing systems to effectively eliminate Carbon dioxide and their rebreathing characteristics were analyzed from the data obtained. CONCLUSION: It can be concluded that apart from the variation of fresh gas flow required in each system and the rebreathing characteristics of the Bain breathing system both Circle absorption system and the Bain breathing system are equally effective in terms of Carbon dioxide elimination and both can effectively provide a conducive environment for intracranial procedures.

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“…The lung model used [7] produced a sinusoidal ventilatory flow pattern, with a tidal volume of 400 ml, tracheal volume equivalent to the deadspace (130 ml) and minute ventilation of 6 litre min" 1 . The peak inspiratory flow rate (PIFR) was measured with a Fleisch pneumotachograph and found to be 20 litre min" 1 .…”

Section: Methodsmentioning

confidence: 99%

Nitrous Oxide Administration Using Commonly Available Oxygen Therapy Devices

Joshi

Ooi

Soni

1992

British Journal of Anaesthesia

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Administration of nitrous oxide is useful for providing sedation and analgesia. The therapeutic range for nitrous oxide is 20-30%. Several oxygen treatment devices have been used for administering nitrous oxide, but little is known about the concentrations of nitrous oxide and oxygen delivered to the trachea. We have studied this, using an analogue lung model, with several oxygen therapy devices. With a 1:1 nitrous oxide-oxygen mixture in the primary flow for all systems, end-expired nitrous oxide concentrations varied between 6.5% and 34.3%. Therapeutic concentrations were produced using the Hudson (nominal oxygen concentration 60%) fixed-performance mask, the variable performance Hudson mask at 4 litre min-1, the MC masks at 4 and 6 litre min-1 and the nasal prongs at 6 and 8 litre min-1. Simultaneous end-expired oxygen concentrations for all devices tested were within a safe range.

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A comparison of anaesthetic breathing systems during spontaneous ventilation

Cited by 23 publications

References 24 publications

Efficiency of an Enclosed Afferent Reservoir Breathing System During Controlled Ventilation

Efficiency of an Enclosed Afferent Reservoir Breathing System During Controlled Ventilation

A Clinical Comparative Study to Ascertain Efficacy of Circle Absorption System and Bain Breathing System in Maintaining Effective Hypocapnia During Intracranial Surgery

Nitrous Oxide Administration Using Commonly Available Oxygen Therapy Devices

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