A comparison of pressure‐ and volume‐controlled ventilation at different inspiratory to expiratory ratios*

Ludwigs, Ulf; Klingstedt, C.; Baehrendtz, S.; Hedenstierna, Göran

doi:10.1111/j.1399-6576.1997.tb04615.x

Cited by 23 publications

(13 citation statements)

References 33 publications

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“…These results indirectly reflect a reduction in the amount of atelectasis and an improvement in V/Q mismatching in the dependent lung 26,27 . Interestingly, most previous studies of inverse ratio ventilation used a more prolonged I:E ratio than 1:1 and PCV with decelerating inspiratory flow in the supine position 10,11,28 , but our results showed that VCV with only a minimal prolonged I:E ratio could result in improved CO 2 elimination and lower ventilatory requirements during OLV.…”

Section: Discussioncontrasting

confidence: 71%

Effects of a 1:1 Inspiratory to Expiratory Ratio on Respiratory Mechanics and Oxygenation during One-Lung Ventilation in the Lateral Decubitus Position

Kim

Choi

Lee

et al. 2012

Anaesth Intensive Care

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Prolonged inspiratory to expiratory (I:E) ratio ventilation may have both positive and negative effects on respiratory mechanics and oxygenation during one-lung ventilation (OLV), but definitive information is currently lacking. We therefore compared the effects of volume-controlled ventilation with I:E ratios of 1:1 and 1:2 on respiratory mechanics and oxygenation during OLV. Fifty-six patients undergoing thoracoscopic lobectomy were randomly assigned volume-controlled ventilation with an I:E ratio of 1:1 (group 1:1, n=28) or 1:2 (group 1:2, n=28) during OLV. Arterial and central venous blood gas analyses and respiratory variables were recorded 15 minutes into two-lung ventilation, at 30 and 60 minutes during OLV, and 15 minutes after two-lung ventilation was re-initiated. Peak and plateau airway pressures in cmH 2 O [standard deviation] during OLV were significantly lower in group 1:1 than in group 1:2 (P <0.01) (19 [3] and 23 [4]; 16 [3] and 19 [5], respectively). The arterial to end-tidal carbon dioxide tension difference was significantly lower in group 1:1 than in group 1:2 (P <0.01), (0.5 [0.3] and 1.1 [0.5]). There were no significant differences in P a O 2 during OLV between the two groups (OLV 30 , P=0.856; OLV 60 , P=0.473). In summary, volume-controlled ventilation with an I:E ratio of 1:1 reduced peak and plateau airway pressures improved dynamic compliance and efficiency of alveolar ventilation, but it did not improve arterial oxygenation in a substantial manner. Furthermore, the associated increase in mean airway pressure might have reduced cardiac output, resulting in a lower central venous oxygen saturation.

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Section: Discussioncontrasting

confidence: 71%

Effects of a 1:1 Inspiratory to Expiratory Ratio on Respiratory Mechanics and Oxygenation during One-Lung Ventilation in the Lateral Decubitus Position

Kim

Choi

Lee

et al. 2012

Anaesth Intensive Care

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“…These results correspond to the finding that by increasing P mean , gas exchange improved, regardless of the inspiratory flow-wave form (18,19). However, other studies have revealed that with adequate PEEP, the increase of P mean does not further improve Pao 2 but may decrease DO 2 because of a decrease of CO (21,22). However, other studies have revealed that with adequate PEEP, the increase of P mean does not further improve Pao 2 but may decrease DO 2 because of a decrease of CO (21,22).…”

Section: Discussionsupporting

confidence: 87%

“…In the present study, P mean increased with V dec when compared with V con . Thus, as suggested by other investigators (21,22), it appears that the increase of oxygenation using PEEP cannot be further improved by PCV with V dec . As a result of the increase of total PEEP from 5 cm H 2 O (ALI) to 8 cm H 2 O (2, 4, and 6 hours) Q S /Q T decreased in both groups.…”

Section: Discussionmentioning

confidence: 69%

Erratum

&NA;

2004

Anesthesia & Analgesia

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In acute lung injury (ALI), controlled mechanical ventilation with decelerating inspiratory flow (V dec ) has been suggested to improve oxygenation when compared with constant flow (V con ) by improving the distribution of ventilation and perfusion (V A /Q ). We performed the present study to test this hypothesis in an animal model of ALI. Furthermore, the effects of combined decelerating and constant flow (V deco ) were evaluated. Thus, 18 pigs with experimental ALI were randomized to receive mechanical ventilation with either V con , V dec or a fixed combination of both flow wave forms (V deco ) at the same tidal volume and positive end-expiratory pressure level for 6 h. Hemodynamics, gas exchange, and V A /Q distribution were determined. The results revealed an improvement of oxygenation resulting from a decrease of pulmonary shunt within each group (P Ͻ 0.05). However, blood flow to lung areas with a normal V A /Q distribution increased only during ventilation with V con (P Ͻ 0.05). Accordingly, Pao 2 was higher with V con than with V dec and V deco (P Ͻ 0.05). We conclude that contrary to the hypothesis, V con provides a more favorable V A /Q distribution, and hence better oxygenation, when compared with V dec and V deco in this model of ALI.(Anesth Analg 2004;98:211-9) I n acute lung injury (ALI), the efficiency of mechanical ventilation to provide adequate pulmonary gas exchange depends mainly on the homogeneity of alveolar ventilation distribution in lung areas with different alveolar opening pressures, thereby determining the ratio of ventilation and perfusion (V A /Q ). According to a mathematical lung model, decelerating inspiratory flow (V dec ) has been suggested to provide a more uniform distribution of inspired gas when compared with constant inspiratory flow (V con ) (1). These assumptions were confirmed by Abraham and Yoshihara (2) in a clinical study comparing volume-controlled mechanical ventilation (VCV) with V con and pressure-controlled mechanical ventilation (PCV) with V dec at equal tidal volumes (Vt) in patients with ALI. The authors demonstrated that changing from V con to V dec may be associated with increased oxygenation. In contrast, other clinical trials revealed a more homogeneous gas distribution but failed to prove an increase of oxygenation from V dec in ALI (3-8). However, previous studies evaluated hemodynamics and conventional gas exchange but did not determine changes of V A /Q distribution. Furthermore, most of them revealed short-term effects of 30 -60 min of experimental intervention (3,5-8). Thus, the potential benefits of PCV with V dec in ALI are still under debate (9). In particular, prolonged effects of different flow patterns on V A /Q distribution in ALI remain unclear.This study was performed to compare V A /Q distribution in experimental ALI in relation to V con during VCV, V dec during PCV and a fixed combination of both flow patterns (V deco ) provided by volume-assured pressure support (VAPS), a dual mode where pressure-controlled inspiration with V dec may be ...

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“…PC-IRV has been found to improve PaCO 2 more than PCV 1:2[1617] or volume-cycled ventilation with PEEP do. [1617] A crossover study[10] evaluated eight patients with ARDS in whom six hours of volume-controlled IRV was compared with six hours of conventional ventilation showed modest improvement in CO 2 while on IRV. In our study, the PaCO 2 was comparable between groups and no significant adjustment in respiratory rate was needed to keep comparable ETCO 2 and PaCO 2 .…”

Section: Discussionmentioning

confidence: 99%

Equal ratio ventilation (1:1) improves arterial oxygenation during laparoscopic bariatric surgery: A crossover study

Mousa

2013

Saudi J Anaesth

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Background:Hypoxaemia and high peak airway pressure (Ppeak) are common anesthetic problems during laparoscopic bariatric surgery. Several publications have reported the successful improvement in arterial oxygenation using positive end expiratory pressure and alveolar recruitment maneuver, however, high peak airway pressure during laparoscopic bariatric surgery may limit the use of both techniques. This study was designed to determine whether equal I:E (inspiratory-to-expiratory) ratio ventilation (1:1) improves arterial oxygenation with parallel decrease in the Ppeak values.Methods:Thirty patients with a body mass index ≥40 kg/m2 scheduled for laparoscopic bariatric surgery were randomized, after creation of pneumoperitoneum, to receive I:E ratio either 1:1 (group 1, 15 patients) or 1:2 (group 2, 15 patients). After a stabilization period of 30 min, patients were crossed over to the other studied I:E ratio. Ppeak, mean airway pressure (Pmean), dynamic compliance (Cdyn), arterial blood gases and hemodynamic data were collected at the end of each stabilization period.Results:Ventilation with I: E ratio of 1:1 significantly increased partial pressure of O2 in the arterial blood (PaO2), Pmean and Cdyn with concomitant significant decrease in Ppeak compared to ventilation with I: E ratio of 1:2. There were no statistical differences between the two groups regarding the mean arterial pressure, heart rate, respiratory rate, end tidal CO2 or partial pressure of CO2 in the arterial blood.Conclusion:Equal ratio ventilation (1:1) is an effective technique in increase PaO2 during laparoscopic bariatric surgery. It increases Pmean and Cdyn while decreasing Ppeak without adverse respiratory or hemodynamic effects.

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A comparison of pressure‐ and volume‐controlled ventilation at different inspiratory to expiratory ratios*

Abstract: Inverse ratio ventilation did not result in improved FRC in comparison to conventional volume-controlled PEEP ventilation. PCIRV allows for a reduction in minute ventilation but the increase in mean airway pressure compromises circulation.

Cited by 23 publications

References 33 publications

Effects of a 1:1 Inspiratory to Expiratory Ratio on Respiratory Mechanics and Oxygenation during One-Lung Ventilation in the Lateral Decubitus Position

Effects of a 1:1 Inspiratory to Expiratory Ratio on Respiratory Mechanics and Oxygenation during One-Lung Ventilation in the Lateral Decubitus Position

Erratum

Equal ratio ventilation (1:1) improves arterial oxygenation during laparoscopic bariatric surgery: A crossover study

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