The Cardiopneumatic Movements

Haycraft, John Berry; Edie, Robert

doi:10.1113/jphysiol.1891.sp000394

Cited by 15 publications

(5 citation statements)

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“…In the early 1980s, Slutsky proposed that cardiogenic oscillations could be a major contributor to apnoeic oxygenation and gas exchange . Cardiogenic oscillations refer to changes in airway gas flow and pressure that are synchronous with the cardiac cycle , and are believed to arise from the movement of blood in pulmonary vessels, causing compression and expansion of the small airways . As under apnoeic conditions the principal intrinsic gas flow within the airway relates to cardiogenic oscillations, we hypothesised that an interaction between supraglottic turbulence generated by high‐flow nasal oxygenation and cardiogenic oscillations might be contributing to the underlying mechanism of THRIVE.…”

Section: Introductionmentioning

confidence: 98%

A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)

et al. 2019

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Summary Clinical observations suggest that compared with standard apnoeic oxygenation, transnasal humidified rapid‐insufflation ventilatory exchange using high‐flow nasal oxygenation reduces the rate of carbon dioxide accumulation in patients who are anaesthetised and apnoeic. This suggests that active gas exchange takes place, but the mechanisms by which it may occur have not been described. We used three laboratory airway models to investigate mechanisms of carbon dioxide clearance in apnoeic patients. We determined flow patterns using particle image velocimetry in a two‐dimensional model using particle‐seeded fluorescent solution; visualised gas clearance in a three‐dimensional printed trachea model in air; and measured intra‐tracheal turbulence levels and carbon dioxide clearance rates using a three‐dimensional printed model in air mounted on a lung simulator. Cardiogenic oscillations were simulated in all experiments. The visualisation experiments indicated that gaseous mixing was occurring in the trachea. With no cardiogenic oscillations applied, mean (SD) carbon dioxide clearance increased from 0.29 (0.04) ml.min−1 to 1.34 (0.14) ml.min−1 as the transnasal humidified rapid‐insufflation ventilatory exchange flow rate was increased from 20 l.min−1 to 70 l.min−1 (p = 0.0001). With a cardiogenic oscillation of 20 ml.beat−1 applied, carbon dioxide clearance increased from 11.9 (0.50) ml.min−1 to 17.4 (1.2) ml.min−1 as the transnasal humidified rapid‐insufflation ventilatory exchange flow rate was increased from 20 l.min−1 to 70 l.min−1 (p = 0.0014). These findings suggest that enhanced carbon dioxide clearance observed under apnoeic conditions with transnasal humidified rapid‐insufflation ventilatory exchange, as compared with classical apnoeic oxygenation, may be explained by an interaction between entrained and highly turbulent supraglottic flow vortices created by high‐flow nasal oxygen and cardiogenic oscillations.

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Section: Introductionmentioning

confidence: 98%

A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)

et al. 2019

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“…During the brief T low , released gas is exchanged with fresh gas to regenerate the gradient for CO 2 diffusion. In addition, cardiogenic mixing results in CO 2 movement toward central airways during the T high or breathhold period (46, [53][54][55], improving the efficacy of the release for ventilation. The addition of spontaneous breaths during the T high period at P high (higher lung volume) further enhances recruitment and ventilation efficiency (Fig.…”

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confidence: 98%

Other approaches to open-lung ventilation: Airway pressure release ventilation

Habashi

2005

Critical Care Medicine

275

297

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APRV may offer potential clinical advantages for ventilator management of acute lung injury/acute respiratory distress syndrome and may be considered as an alternative "open lung approach" to mechanical ventilation. Whether APRV reduces mortality or increases ventilator-free days compared with a conventional volume-cycled "lung protective" strategy will require future randomized, controlled trials.

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“…Conversely, with a brief inspiratory time, expiration begins when PACO 2 is at its nadir. Physiologic data demonstrate optimizing diffusive and convective gas exchange [bulk flow of exhaled gas into the environment] increases ventilation efficiency, thus lowering MVe requirements for equivalent PaCO 2 clearance ( Haycroft and Edie, 1891 ; Knelson et al, 1970 ; Engel et al, 1973 ; Fukuchi et al, 1976 ; Fuleihan et al, 1976 ; Fredberg, 1980 ; Valentine et al, 1991 ; Falkenhain et al, 1992 ; Smith and Smith, 1995 ; Mercat et al, 2001 ; Tsuda et al, 2011 ; Aboab et al, 2012 ). The concept that alveolar recruitment and derecruitment is time-dependent is often overlooked by clinicians.…”

Section: Myth #5—it Is Difficult To Control Paco 2 ...mentioning

confidence: 99%

Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal

et al. 2022

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In the pursuit of science, competitive ideas and debate are necessary means to attain knowledge and expose our ignorance. To quote Murray Gell-Mann (1969 Nobel Prize laureate in Physics): “Scientific orthodoxy kills truth”. In mechanical ventilation, the goal is to provide the best approach to support patients with respiratory failure until the underlying disease resolves, while minimizing iatrogenic damage. This compromise characterizes the philosophy behind the concept of “lung protective” ventilation. Unfortunately, inadequacies of the current conceptual model–that focuses exclusively on a nominal value of low tidal volume and promotes shrinking of the “baby lung” - is reflected in the high mortality rate of patients with moderate and severe acute respiratory distress syndrome. These data call for exploration and investigation of competitive models evaluated thoroughly through a scientific process. Airway Pressure Release Ventilation (APRV) is one of the most studied yet controversial modes of mechanical ventilation that shows promise in experimental and clinical data. Over the last 3 decades APRV has evolved from a rescue strategy to a preemptive lung injury prevention approach with potential to stabilize the lung and restore alveolar homogeneity. However, several obstacles have so far impeded the evaluation of APRV’s clinical efficacy in large, randomized trials. For instance, there is no universally accepted standardized method of setting APRV and thus, it is not established whether its effects on clinical outcomes are due to the ventilator mode per se or the method applied. In addition, one distinctive issue that hinders proper scientific evaluation of APRV is the ubiquitous presence of myths and misconceptions repeatedly presented in the literature. In this review we discuss some of these misleading notions and present data to advance scientific discourse around the uses and misuses of APRV in the current literature.

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The Cardiopneumatic Movements

Cited by 15 publications

References 0 publications

A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)

A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE)

Other approaches to open-lung ventilation: Airway pressure release ventilation

Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal

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