Direct tracheal airway pressure measurements are essential for safe and accurate dynamic monitoring of respiratory mechanics. A laboratory study

Kárason, Sigurbergur; Søndergaard, Søren; Lundin, S.; Wiklund, J.; Stenqvist, O.

doi:10.1034/j.1399-6576.2001.450207.x

Cited by 45 publications

(61 citation statements)

References 28 publications

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“…However, a 6-Fr catheter recommended for a 2.5 ETT in the presence of thick secretions could result in large subatmospheric airway pressures if suction continued once secretions were cleared, and V T is likely to be significantly reduced during the procedure. Furthermore, such secretions may adhere to the ETT inner surface and increase resistance (21,22), which may lead to airway pressures lower than have been recorded in this study.…”

Section: Discussionmentioning

confidence: 52%

“…In the clinical setting, airway pressure and V T are likely to be influenced by the volume and consistency of mucus. Secretions adhering to the ETT can cause considerable narrowing of the ETT lumen (21,22), which could result in greater loss of pressure and V T during suction, whereas secretions entering the catheter will tend to inhibit a fall in pressure (26). However, suction in the absence of secretions can occur in clinical practice (26) and may occur toward the end of the procedure when secretions have been cleared, especially with multiple passes of the catheter.…”

Section: Discussionmentioning

confidence: 96%

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The Effects of Closed Endotracheal Suction on Ventilation During Conventional and High-Frequency Oscillatory Ventilation

et al. 2009

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ABSTRACT:In newborn infants, closed endotracheal tube (ETT) suction may reduce associated adverse effects, but it is not clear whether ventilation is maintained during the procedure. We aimed to determine the effect of ETT size, catheter size, and suction pressure on ventilation parameters measured distal to the ETT. Suction was performed on a test lung, ventilated with conventional (CMV) and high-frequency oscillatory ventilation (HFOV) using ETT sizes 2.5-4.0 mm, catheter sizes 5-8 French gauge (Fr), and suction pressures 80 -200 mm Hg. Tracheal and circuit peak inspiratory pressure, positive end-expiratory pressure, and tracheal tidal volume (V T ) were recorded for each suction episode. During both CMV and HFOV, tracheal pressures and V T were considerably reduced by suctioning; this reduction was dependent on the combination of ETT, catheter, and suction pressure. Loss of V T , inflation pressure (CMV), and pressure amplitude (HFOV) occurred primarily with insertion of the catheter, and loss of end-expiratory pressure (CMV) and mean tracheal pressure (HFOV) occurred with the application of suction. Circuit pressures were reduced to lesser degree. We conclude that airway pressures and V T are not maintained during closed endotracheal suction with either CMV or HFOV, and choice of equipment and settings will affect the degree of interruption to ventilation. (Pediatr Res 66: 400-404, 2009) E ndotracheal tube (ETT) suction is performed periodically on infants receiving mechanical ventilation to clear secretions from the ETT and airway. Although necessary, it is associated with adverse effects including atelectasis, hypoxemia, and cardiovascular instability, partly attributable to loss of airway pressure and interruption of ventilation (1-5). Closed suction, performed without disconnection from respiratory support, has been shown to reduce adverse effects (6 -8), but whether ventilation is maintained during closed suction has not been demonstrated in a neonatal population.With adult-sized ETTs, airway pressure has been shown to decrease during closed suction and concerns have been raised about the potential for very large negative airway pressures during the procedure (4,9,10). However only one study has quantified pressure and tidal volume (V T ) changes during closed suction with neonatal equipment (11). Using an in vitro model, a considerable reduction in airway pressures and V T was demonstrated, particularly when a large catheter relative to the ETT was used. However, the authors did not report results using 5 or 7 French gauge (Fr) suction catheters, nor did they measure the effect of varying the suction pressure.Airway pressures during closed suction are influenced by ventilation mode in adult models (4,10), but this effect has not been studied using neonatal ventilators. Of particular interest is the performance of closed suction catheters during highfrequency oscillatory ventilation (HFOV), because closed suction is generally recommended for patients receiving this ventilation mode (12,13).This study ai...

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Section: Discussionmentioning

confidence: 52%

Section: Discussionmentioning

confidence: 96%

The Effects of Closed Endotracheal Suction on Ventilation During Conventional and High-Frequency Oscillatory Ventilation

et al. 2009

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“…Tracheal pressure in the animal studies (II, III) was measured with a fluid filled pressure line inserted into the tracheal tube and positioned 2 cm below the tip of the tube. In patients, the pressure line was inserted in the same way but filled with air (IV) [90,91]. All transducers were connected with the AS/3 (I, II, III) or S5 (IV) modular monitor (Datex-Ohmeda/GE, Finland).…”

Section: Lung Mechanics (I II Iii Iv)mentioning

confidence: 99%

Regional lung derecruitment after endotracheal suction during volume- or pressure-controlled ventilation: a study using electric impedance tomography

et al. 2006

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“…However, it should be possible to predict the effect of different tidal volumes, since the EEV is only correlated to PEEP, as long as the flow rates do not change drastically. This impact of flow rates is distinct due to the use of easily available proximal data [35,36], and the airway resistance changes when flow rates change drastically. This limitation also implies that when the ventilator setting is changed drastically, the model needs to be refit and re-identified using 2 or more PV loops at these new ventilation setting.…”

Section: Model and Study Limitationsmentioning

confidence: 99%

A minimal model of lung mechanics and model-based markers for optimizing ventilator treatment in ARDS patients

Sundaresan

Yuta

Hann

et al. 2009

Computer Methods and Programs in Biomedicine

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A majority of patients admitted to the Intensive Care Unit (ICU) require some form of respiratory support. In the case of Acute Respiratory Distress Syndrome (ARDS), the patient often requires full intervention from a mechanical ventilator. ARDS is also associated with mortality rate as high as 70%. Despite many recent studies on ventilator treatment of the disease, there are no well established methods to determine the optimal Positive End Expiratory Pressure (PEEP) or other critical ventilator settings for individual patients. A model of fundamental lung mechanics is developed based on capturing the recruitment status of lung units. The main objective of this research is the simplest possible model that is clinically effective in determining PEEP. The model was identified for a variety of different ventilator settings using clinical data. The fitting error was between 0.1% to 4% over the inflation limb and between 0.3% to 13% over the deflation limb at different PEEP settings. The model produces good correlation with clinical data, and is clinically applicable due to the minimal number of patient specific parameters to identify. The ability to use this identified patient specific model to optimize ventilator management is demonstrated by its ability to predict the patient specific response of PEEP changes before clinically applying them. Predictions of recruited lung volume change with change in PEEP have a median absolute error of 1.87% (IQR:0.93-4.80%; 90% CI:0.16-11.98%) for inflation and a median of 5.76% (IQR:2.71-10.50%; 90% CI:0.43-17.04%) for deflation, across all data sets and PEEP values (N = 34 predictions). This minimal model thus provides a clinically useful and simple platform for continuous patient specific monitoring of lung unit recruitment for a patient.

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Direct tracheal airway pressure measurements are essential for safe and accurate dynamic monitoring of respiratory mechanics. A laboratory study

Abstract: ETT connections and secretions cause a variance in resistance. Tracheal pressure can be measured with high precision with an air- or liquid-filled catheter. An end hole catheter placed within 2 cm above or below the ETT tip will give sufficiently precise measurements for clinical purposes.

Cited by 45 publications

References 28 publications

The Effects of Closed Endotracheal Suction on Ventilation During Conventional and High-Frequency Oscillatory Ventilation

The Effects of Closed Endotracheal Suction on Ventilation During Conventional and High-Frequency Oscillatory Ventilation

Regional lung derecruitment after endotracheal suction during volume- or pressure-controlled ventilation: a study using electric impedance tomography

A minimal model of lung mechanics and model-based markers for optimizing ventilator treatment in ARDS patients

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