Biologically variable ventilation improves oxygenation and respiratory mechanics in a porcine model of one-lung ventilation

Background Hypoxemia is common during one-lung ventilation (OLV). Atelectasis contributes to the problem. Biologically variable ventilation (BVV), using microprocessors to reinstitute physiologic variability to respiratory rate and tidal volume, has been shown to be advantageous over conventional monotonous control mode ventilation (CMV) in improving oxygenation during the period of lung reinflation after OLV in an experimental model. Here, using a porcine model, the authors compared BVV with CMV during OLV to assess gas exchange and respiratory mechanics. Methods Eight pigs (25-30 kg) were studied in each of two groups. After induction of anesthesia-tidal volume 12 ml/kg with CMV and surgical intervention-tidal volume was reduced to 9 ml/kg. OLV was initiated with an endobronchial blocker, and the animals were randomly allocated to either continue CMV or switch to BVV for 90 min. After OLV, a recruitment maneuver was undertaken, and both lungs were ventilated for a further 60 min. At predetermined intervals, hemodynamics, respiratory gases (arterial, venous, and end-tidal samples) and mechanics (airway pressures, static and dynamic compliances) were measured. Derived indices (pulmonary vascular resistance, shunt fraction, and dead space ventilation) were calculated. Results By 15 min of OLV, arterial oxygen tension was greater in the BVV group (group x time interaction, P = 0.003), and shunt fraction was lower with BVV from 30 to 90 min (group effect, P = 0.0004). From 60 to 90 min, arterial carbon dioxide tension was lower with BVV (group x time interaction, P = 0.0001) and dead space ventilation was less from 60 to 90 min (group x time interaction, P = 0.0001). Static compliance was greater by 60 min of BVV and remained greater during return to ventilation of both lungs (group effect, P = 0.0001). Conclusions In this model of OLV, BVV resulted in superior gas exchange and respiratory mechanics when compared with CMV. Improved static compliance persisted with restoration of two-lung ventilation.

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Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation

Anesthesiology ◽

10.1097/aln.0000000000002011 ◽

2018 ◽

Vol 128 (3) ◽

pp. 531-538 ◽

Cited By ~ 18

Author(s):

Savino Spadaro ◽

Salvatore Grasso ◽

Dan Stieper Karbing ◽

Alberto Fogagnolo ◽

Marco Contoli ◽

...

Keyword(s):

Respiratory Mechanics ◽

Lung Ventilation ◽

Random Order ◽

Driving Pressure ◽

Shunt Fraction ◽

Positive End Expiratory Pressure ◽

One Lung Ventilation ◽

Predicted Body Weight ◽

Arterial Blood Gas ◽

Arterial Blood

Abstract Background Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation. Methods Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements. Results During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The Pao2/Fio2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change. Conclusions During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

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Effects of PEEP on oxygenation and respiratory mechanics during one-lung ventilation

British Journal of Anaesthesia ◽

10.1093/bja/aei178 ◽

2005 ◽

Vol 95 (2) ◽

pp. 267-273 ◽

Cited By ~ 45

Author(s):

P. Michelet ◽

A. Roch ◽

D. Brousse ◽

X.-B. D'Journo ◽

F. Bregeon ◽

...

Keyword(s):

Respiratory Mechanics ◽

Lung Ventilation ◽

One Lung Ventilation

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Positive end-expiratory pressure applied to the dependent lung during one-lung ventilation improves oxygenation and respiratory mechanics in patients with high FEV1

European Journal of Anaesthesiology ◽

10.1097/00003643-200412000-00003 ◽

2004 ◽

Vol 21 (12) ◽

pp. 938-943 ◽

Cited By ~ 26

Author(s):

F. Valenza ◽

G. Ronzoni ◽

L. Perrone ◽

M. Valsecchi ◽

S. Sibilla ◽

...

Keyword(s):

Respiratory Mechanics ◽

Lung Ventilation ◽

Dependent Lung ◽

Positive End Expiratory Pressure ◽

One Lung Ventilation

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Lung computed tomography density distribution in a porcine model of one-lung ventilation

British Journal of Anaesthesia ◽

10.1093/bja/aep006 ◽

2009 ◽

Vol 102 (4) ◽

pp. 551-560 ◽

Cited By ~ 19

Author(s):

A. Kozian ◽

T. Schilling ◽

H. Schütze ◽

F. Heres ◽

T. Hachenberg ◽

...

Keyword(s):

Computed Tomography ◽

Density Distribution ◽

Porcine Model ◽

Lung Ventilation ◽

One Lung Ventilation

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Changes in respiratory mechanics of artificial pneumothorax two-lung ventilation in video-assisted thoracoscopic esophagectomy in prone position

Scientific Reports ◽

10.1038/s41598-021-86554-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yoshinori Tanigawa ◽

Kimihide Nakamura ◽

Tomoko Yamashita ◽

Akira Nakagawachi ◽

Yoshiro Sakaguchi

Keyword(s):

Esophageal Cancer ◽

Prone Position ◽

Respiratory Mechanics ◽

Lung Ventilation ◽

Thoracoscopic Esophagectomy ◽

Secondary Outcome ◽

One Lung Ventilation ◽

Cancer Data ◽

Video Assisted ◽

Artificial Pneumothorax

AbstractWe aimed to clarify the changes in respiratory mechanics and factors associated with them in artificial pneumothorax two-lung ventilation in video-assisted thoracoscopic esophagectomy in the prone position (PP-VATS-E) for esophageal cancer. Data of patients with esophageal cancer, who underwent PP-VATs-E were retrospectively analyzed. Our primary outcome was the change in the respiratory mechanics after intubation (T1), in the prone position (T2), after initiation of the artificial pneumothorax two-lung ventilation (T3), at 1 and 2 h (T4 and T5), in the supine position (T6), and after laparoscopy (T7). The secondary outcome was identifying factors affecting the change in dynamic lung compliance (Cdyn). Sixty-seven patients were included. Cdyn values were significantly lower at T3, T4, and T5 than at T1 (p < 0.001). End-expiratory flow was significantly higher at T4 and T5 than at T1 (p < 0.05). Body mass index and preoperative FEV1.0% were found to significantly influence Cdyn reduction during artificial pneumothorax and two-lung ventilation (OR [95% CI]: 1.29 [1.03–2.24] and 0.20 (0.05–0.44); p = 0.010 and p = 0.034, respectively]. Changes in driving pressure were nonsignificant, and hypoxemia requiring treatment was not noted. This study suggests that in PP-VATs-E, artificial pneumothorax two-lung ventilation is safer for the management of anesthesia than conventional one-lung ventilation (UMIN Registry: 000042174).

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