Pressure Controlled Inverse Ratio Ventilation in Severe Adult Respiratory Failure

Tharratt, R. Steven; Allen, Roblee P.; Albertson, Timothy E

doi:10.1378/chest.94.4.755

Cited by 225 publications

(62 citation statements)

References 21 publications

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“…The recruitment process caused by the long-lasting inspiratory pressure seems to open the alveoli "one by one". This has also been observed by others [38,47,54,55], and may be the reason why positive effects of IRV could not be assured by studies with shorter observation periods [48,[49][50][51]. Thus, pulmonary gas exchange should be monitored for a sufficient period of time (i.e.…”

Section: Variation Of the Inspiration:expiration (I:e) Ratiomentioning

confidence: 75%

“…In 31 ARDS patients [47], pulmonary gas exchange improved during PC-IRV, however, the volume-controlled ventilation (not in IRV mode) was only compared retrospectively. More recent studies on PC-IRV in ARDS patients [48][49][50][51] revealed inconsistent results in comparison with conventional ventilation.…”

Section: Variation Of the Inspiration:expiration (I:e) Ratiomentioning

confidence: 99%

“…several hours) waiting for the expected positive effects of IRV. Unfortunately, the few long-term studies mentioned above are either retrospective and noncontrolled [38,47], or have considered only a small number of patients [54,55]. The main reason for this might be the difficulties of performing such long-term studies under stable conditions in intensive care medicine.…”

Section: Variation Of the Inspiration:expiration (I:e) Ratiomentioning

confidence: 99%

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New strategies in mechanical ventilation for acute lung injury

Burchardi¹

1996

Eur Respir J

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In the fluid-filled lungs of early adult respiratory distress syndrome (ARDS) the dependent parts are compressed and atelectatic; whereas, the nondependent areas remain aerated and functional. Ventilating these considerably restricted lungs carries the risk of overinflation and ventilatory-induced lung injury (baro-volutrauma).The consequences for adjusting mechanical ventilation are: 1) reducing tidal volumes in order to avoid alveolar hyperinflation and excessive alveolar pressures; 2) considering permissive hypercapnia if adequate CO 2 elimination cannot be maintained; 3) keeping open the unstable alveoli by positive end-expiratory pressure (PEEP) (external or intrinsic). However, the large variations in regional lung compliance make it improbable that an optimal external PEEP level beneficial for the whole lung will be found; 4) using intrinsic PEEP in the inverse ratio ventilation (IRV) mode which varies with differences in regional ventilatory kinetics. No clinical study has yet convincingly demonstrated the benefit of IRV compared to conventional ventilation, controlled clinical long-term trials are not yet available; and 5) using superimposed spontaneous breathing which may be considerably more effective in opening up collapsed alveoli, combined with intentional intrinsic PEEP this is achieved in airway pressure release ventilation (APRV).Other new principles of mechanical ventilation, such as "proportional assist ventilation" or "tracheal gas insufflation" must still be considered as experimental. Eur Respir J., 1996Respir J., , 9, 1063 SERIES 'CLINICAL PHYSIOLOGY IN RESPIRATORY INTENSIVE CARE' Edited by A. Rossi and C. RoussosMechanical ventilation and ventilatory support techniques have undergone an impressive evolution within the last 10 yrs. This was due to considerable technical development rather than a radical change in our pathophysiological knowledge. Today, a variety of new techniques are available which facilitate new ventilatory strategies. In this review, only strategies for nonobstructive acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) will be presented and discussed. Strategies for chronic obstructive airways diseases (COPD) differ considerably; they will not be mentioned in this connection. Pathophysiological basisIn ALI and ARDS, (the American-European Consensus Conference on ARDS [1] changed the former expression "adult respiratory distress syndrome" into "acute respiratory distress syndrome", since ARDS is not limited to adults), the hallmark is a critical increase of pulmonary membrane permeability. This can happen by two different pathways: directly by lesion of lung cells; and indirectly as the result of an acute systemic inflammatory reaction (cellular and humoral effects). This results in a bilateral pulmonary interstitial and intra-alveolar (noncardiogenic) oedema.As a consequence, alveoli are compressed or flooded, and the surface for pulmonary gas exchange is considerably reduced by multiple atelectases. In this way, venous admixture and intr...

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Section: Variation Of the Inspiration:expiration (I:e) Ratiomentioning

confidence: 75%

Section: Variation Of the Inspiration:expiration (I:e) Ratiomentioning

confidence: 99%

Section: Variation Of the Inspiration:expiration (I:e) Ratiomentioning

confidence: 99%

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New strategies in mechanical ventilation for acute lung injury

Burchardi¹

1996

Eur Respir J

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“…In the mid-1980s there were reports of improved oxygenation with pressure controlled inverse-ratio ventilation (PCIRV), [61][62][63][64][65] and for some time in the decade thereafter there was enthusiasm for this method. With PCIRV, an inspiratory time greater than the expiratory time is used to increase mean airway pressure and thus improve arterial oxygenation.…”

Section: Prolonged Inspiratory Time and Inverse Inspiratory-expiratormentioning

confidence: 99%

Approaches to Conventional Mechanical Ventilation of the Patient With Acute Respiratory Distress Syndrome

Hess

2011

Respir Care

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To minimize ventilator-induced lung injury, attention should be directed toward avoidance of alveolar over-distention and cyclical opening and closure of alveoli. The most impressive study of mechanical ventilation to date is the Acute Respiratory Distress Syndrome (ARDS) Network study of higher versus lower tidal volume (V T ), which reported a reduction in mortality from 39.8% to 31.0% with 6 mL/kg ideal body weight rather than 12 mL/kg ideal body weight (number-neededto-treat of 12 patients). To achieve optimal lung protection, the lowest plateau pressure and V T possible should be selected. What is most important is limitation of V T and alveolar distending pressure, regardless of the mode set on the ventilator. Accumulating observational evidence suggests that V T should be limited in all mechanically ventilated patients-even those who do not have ALI/ARDS. Evidence does not support the use of pressure controlled inverse-ratio ventilation. Although zero PEEP is probably injurious, an area of considerable controversy is the optimal setting of PEEP. Available evidence does not support the use of higher PEEP, compared to lower PEEP, in unselected patients with acute lung injury (ALI)/ARDS. However, results of a metaanalysis using individual patients from 3 randomized controlled trials suggest that higher PEEP should be used for ARDS, whereas lower PEEP may be more appropriate in patients with ALI. PEEP should be set to maximize alveolar recruitment while avoiding over-distention. Many approaches for setting PEEP have been described, but evidence is lacking that any one approach is superior to any other. In most, if not all, cases of ALI/ARDS, conventional ventilation strategies can be used effectively to provide lung-protective ventilation strategies.

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“…As expected, APRV allowed inverse-ratio ventilation without use of NMBA, and a consequential reduction in sedation requirements. However, PCV-inverse-ratio ventilation, a relatively popular mode of mechanical ventilation for severe ARDS in the late 1980s, 33 is seldom used in contemporary practice, 34 and the results of that study cannot be generalized to contemporary management of ALI/ARDS.…”

Section: Sedation Duration Of Mechanical Ventilation and Other Outcmentioning

confidence: 99%

Patient-Ventilator Interaction During Acute Lung Injury, and the Role of Spontaneous Breathing: Part 2: Airway Pressure Release Ventilation

Kallet

2011

Respir Care

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Airway pressure release ventilation (APRV) and bi-level positive airway pressure (BIPAP) are proposed to reduce patient work of breathing (WOB) sufficiently and to obviate issues related to patient-ventilator synchrony, so that spontaneous breathing can be maintained throughout the course of acute lung injury (ALI). Thus, APRV/BIPAP should reduce requirements for sedation and muscle paralysis, and thereby reduce the duration of mechanical ventilation. Only 17 human, animal, or lung-model studies have examined these claims, either directly or indirectly. Most did not target patients with ALI. Studies on sedation use have serious methodological limitations. Other studies found that APRV/BIPAP either increased WOB and asynchrony, or had no effect on energy expenditure. To supplement the discussion of patient WOB during APRV/BIPAP in ALI, 4 clinical examples showed marked elevation and wide variation in patient WOB. One plausible explanation is that spontaneous breathing is superimposed upon the mechanical ventilation pattern. Thus a variety of "breathing environments" exist during APRV/BIPAP that affect patient WOB and respiratory drive differently and perhaps unpredictably. This characteristic of APRV/BIPAP makes WOB comparisons with traditional modes problematic. Furthermore, the theoretical benefits of APRV, in terms of controlling patient WOB, appear particularly limited when lung-protective 190RESPIRATORY CARE

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Pressure Controlled Inverse Ratio Ventilation in Severe Adult Respiratory Failure

Cited by 225 publications

References 21 publications

New strategies in mechanical ventilation for acute lung injury

New strategies in mechanical ventilation for acute lung injury

Approaches to Conventional Mechanical Ventilation of the Patient With Acute Respiratory Distress Syndrome

Patient-Ventilator Interaction During Acute Lung Injury, and the Role of Spontaneous Breathing: Part 2: Airway Pressure Release Ventilation

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