The Temperature and Humidity in a Low-Flow Anesthesia Workstation With and Without a Heat and Moisture Exchanger

Castro, Jair de; Bolfi, Fernanda; Carvalho, Lídia Raquel de; Bráz, José Reinaldo Cerqueira

doi:10.1213/ane.0b013e31822402df

Cited by 22 publications

(28 citation statements)

References 15 publications

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“…Another approach was presented by Ricard et al [19], with a long-term study on HME performance (around 7 d) showing the ability to detect performance decrease during HME lifetime, even if the system did not provide fast responses. Castro et al [20] designed an interesting in vivo monitoring system, by means of an electronic digital thermo-hygrometer with an accuracy of 2% for RH and 0.5 °C for T, and response times of 1.4 s for 90% RH response and 150 ms for 90% T response. The minimal values averaged over four respiratory cycles of T and absolute humidity (AH) on the patient's side were used to assess the effective humidification of air introduced by HME inside an anesthesia workstation.…”

Section: Introductionmentioning

confidence: 99%

“…The efficiency is described as the ability of the HME to transfer, to the patient, a part of the heat and humidity of the exhaled air to the inhaled air, limiting the amount of humidity and heat loss [15,20,26]. The efficacy is defined as the ability of the HME to properly condition the air to the patient, and it is represented by the T and AH of the air inhaled by the patient, conditioned by the HME [15,20,27]. Finally, heat and moisture losses are described as an indicator of the ability of the HME to avoid the dispersion of heat and moisture from the HME [20].…”

Section: Introductionmentioning

confidence: 99%

“…The efficacy is defined as the ability of the HME to properly condition the air to the patient, and it is represented by the T and AH of the air inhaled by the patient, conditioned by the HME [15,20,27]. Finally, heat and moisture losses are described as an indicator of the ability of the HME to avoid the dispersion of heat and moisture from the HME [20].…”

Section: Introductionmentioning

confidence: 99%

“…The majority of previous analyses studied the conditioning properties in a laboratory setting [11,12] or the effects of HMEs on health conditions [19]. Only few studies monitored HME in an ICU real-use setting [18,20] during mechanical ventilation. The unique and main novelty of our proposal relies on portability, low weight, a user-friendly interface and low power, which ensure complete integration with the clinical setup for continuous evaluation of HME performance in a real-use setting.…”

Section: Introductionmentioning

confidence: 99%

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A compact low-power wireless system for in vivo evaluation of heat and moisture exchanger performance

Bellitti

Bodini

Borghetti

et al. 2018

Meas. Sci. Technol.

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Reliable tools for monitoring heat and moisture exchanger (HME) performance are in high demand by physicians, in order to assess the proper air conditioning delivered to intensive care unit (ICU) patients undergoing mechanical ventilation. To date, there is no system that comprehends all the requirements for clinical applications, in terms of performance and design. In this paper, a compact measurement system is proposed for monitoring HME performance in vivo, comparing the results with in vitro testing outcomes. The portable system presented is connected to the ventilation circuit close to the HME and assures wide compatibility with the new generation of smart devices because of its embedded Bluetooth low-energy module. Low power consumption ensures long-term monitoring capability of more than 24 h. Laboratory tests performed both in static and dynamic conditions showed rise-and fall-times for humidity measurements between 1 s and 1.8 s, compatible with many common variations in working operative conditions during mechanical ventilation. Clinical tests performed in the ICU demonstrated the possibility to effectively and continuously monitor in vivo HME performance. Furthermore, the comparison of the in vivo performances with the in vitro standard procedure and the agreement of the parameter ranges monitored allowed us to confirm the reliability of the system, highlighting the usefulness of this approach for proper real time HME monitoring.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A compact low-power wireless system for in vivo evaluation of heat and moisture exchanger performance

Bellitti

Bodini

Borghetti

et al. 2018

Meas. Sci. Technol.

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show abstract

“…[9] The Primus anesthesia workstation also had a significant effect on the temperature, relative humidity, and absolute humidity of the respiratory gas with low FGF. [10] …”

Section: Introductionmentioning

confidence: 99%

Comparison of the temperature and humidity in the anesthetic breathing circuit among different anesthetic workstations

Choi

Min²,

Park

et al. 2017

Medicine

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Background:For patients undergoing general anesthesia, adequate warming and humidification of the inspired gases is very important. The aim of this study was to evaluate the differences in the heat and moisture content of the inspired gases with low-flow anesthesia using 4 different anesthesia machines.Methods:The patients were divided into 11 groups according to the anesthesia machine used (Ohmeda, Excel; Avance; Dräger, Cato; and Primus) and the fresh gas flow (FGF) rate (0.5, 1, and 4 L/min). The temperature and absolute humidity of the inspired gas in the inspiratory limbs were measured at 5, 10, 15, 30, 45, 60, 75, 90, 105, and 120 minutes in 9 patients scheduled for total thyroidectomy or cervical spine operation in each group.Results:The anesthesia machines of Excel, Avance, Cato, and Primus did not show statistically significant changes in the inspired gas temperatures over time within each group with various FGFs. They, however, showed statistically significant changes in the absolute humidity of the inspired gas over time within each group with low FGF anesthesia (P < .05). The anesthesia machines of Cato and Primus showed statistically significant changes in the absolute humidity of the inspired gas over time within each group with an FGF of 4 L/min (P < .05). However, even with low-flow anesthesia, the temperatures and absolute humidities of the inspired gas for all anesthesia machines were lower than the recommended values.Conclusion:There were statistical differences in the provision of humidity among different anesthesia workstations. The Cato and Primus workstations were superior to Excel and Avance. However, even these were unsatisfactory in humans. Therefore, additional devices that provide inspired gases with adequate heat and humidity are needed for those undergoing general anesthetic procedures.

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The Circle System

Truchetti¹,

Farry

2018

Veterinary Anesthetic and Monitoring Equipment

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The Temperature and Humidity in a Low-Flow Anesthesia Workstation With and Without a Heat and Moisture Exchanger

Abstract: The Primus anesthesia workstation partially humidifies the inspired gas when a low fresh gas flow is used. Insertion of an HME increases the humidity in inhaled gas, bringing it close to physiological values.

Cited by 22 publications

References 15 publications

A compact low-power wireless system for in vivo evaluation of heat and moisture exchanger performance

A compact low-power wireless system for in vivo evaluation of heat and moisture exchanger performance

Comparison of the temperature and humidity in the anesthetic breathing circuit among different anesthetic workstations

The Circle System

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