Decelerating inspiratory flow waveform improves lung mechanics and gas exchange in patients on intermittent positive-pressure ventilation

Al-Saady, N.; Bennett, E. D.

doi:10.1007/bf00254777

Cited by 157 publications

(87 citation statements)

References 28 publications

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“…Also, no differences were found in gas exchange and WOB between the two wave forms. The present results differ with those of AL SAADY and BENNETT [33], in which the decelerating wave flow pattern produced a significant increase in arterial oxygenation. The decelerating wave flow pattern may be more effective in patients with heterogeneous respiratory mechanics and prolonged alveolar time constants (i.e.…”

Section: Assist Control Ventilation and Assist Pressure Control Venticontrasting

confidence: 99%

“…In a previous study, similar results were obtained by the present authors, by increasing the PIF during PSV, where the highest PIF did not further reduce the WOB and was associated with patient discomfort [36]. Both these studies suggest that there is a threshold of flow demand below which a lower flow rate increases the WOB and above which a further increase of flow rate is not beneficial and may be uncomfortable [33,35]. In the present study, only minor variations of PIFs were applied, according to clinical indications, and the authors did not find such a flow threshold, which would probably occur at a higher flow rate.…”

Section: Assist Control Ventilation: Effect Of Different Peak Inspirasupporting

confidence: 90%

“…constant flow). In the latest generation of mechanical ventilators, however, the decelerating wave flow pattern is often available even in the volume-limited modes [33]. With the square wave flow pattern, the flow rate remains relatively constant after reaching the PIF, while with the decelerating wave flow pattern, the flow rapidly reaches the PIF value and then decreases linearly afterwards to 50% by the end of inspiration [20].…”

Section: Assist Control Ventilation and Assist Pressure Control Ventimentioning

confidence: 99%

See 2 more Smart Citations

Different modes of assisted ventilation in patients with acute respiratory failure

Chiumello¹,

Pelosi²,

Calvi³

et al. 2002

European Respiratory Journal

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The aim of the present study was to verify that the patient/ventilator interaction is similar, regardless of the mode of assisted mechanical ventilation (i.e. pressure-or volume-limited) used, if tidal volume (VT) and peak inspiratory flow (PIF) are matched. Therefore, the authors compared the effects of three different modes of assisted ventilation on the work of breathing (WOB) and gas exchange in patients with acute respiratory failure.For Protocol 1, in seven patients, the authors compared pressure support, assist pressure control and assist control (with square and decelerating wave inspiratory flow pattern) set to deliver the same VT and PIF. For Protocol 2, in another 10 patients, the authors compared pressure support and assist control with high (0.8 L?s -1 ) and low (0.6 L?s -1 ) PIFs set to deliver the same VT.In Protocol 1, there was no difference in WOB and gas exchange between the three modes of assisted ventilation tested. In Protocol 2, the decrease of PIFs during assist control significantly increased WOB.In conclusion, different modes of assisted ventilation similarly reduce work of breathing and provide adequate gas exchange at fixed tidal volume and peak inspiratory flow only. During assist control, tidal volume and peak inspiratory flow (set by the physician) are the main determinants of the patient/ventilator interaction. A primary goal of mechanical ventilation is to improve gas exchange and reduce the work of breathing (WOB) of patients with acute respiratory failure, without causing iatrogenic lung injury [1]. Assisted ventilation allows the patient to contribute to minute ventilation (V9E) and offers several advantages over controlled ventilation. It can reduce the need for sedation and paralysis, decrease the risk of barotrauma [2], improve intrapulmonary gas distribution [3], and prevent muscle atrophy [4,5]. During assisted ventilation, the WOB is dependent on both the ventilator settings and the patient9s ventilatory demand and mechanics.Pressure support ventilation (PSV) is a pressurelimited, flow-cycled mode of assisted ventilation, in which each breath is supported by a constant level of pressure at the airway (Paw), so that the tidal volume (VT) and inspiratory flow are more adaptable to the patient9s own ventilatory demand [6]. This manner of supporting the patient9s own ventilatory effort may be responsible for an improved comfort and synchrony with the ventilator, and has been shown to reduce the WOB and prevent diaphragmatic fatigue in patients with respiratory failure [7]. The main disadvantage of PSV is that it only works best in patients with stable respiratory conditions (i.e. an adequate sufficient ventilatory drive and somewhat preserved respiratory mechanics [8,9]).Assist control ventilation (ACV) is a volume-limited mode of assisted ventilation, in which the VT and the peak inspiratory flow (PIF) are set by the clinician and are not altered by the patient9s ventilatory demand. If the required VT and inspiratory flow are higher than what the ventilator suppli...

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Section: Assist Control Ventilation and Assist Pressure Control Venticontrasting

confidence: 99%

Section: Assist Control Ventilation: Effect Of Different Peak Inspirasupporting

confidence: 90%

Section: Assist Control Ventilation and Assist Pressure Control Ventimentioning

confidence: 99%

See 1 more Smart Citation

Different modes of assisted ventilation in patients with acute respiratory failure

Chiumello¹,

Pelosi²,

Calvi³

et al. 2002

European Respiratory Journal

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“…It delivers the preset VT with the lowest possible pressure. Unfortunately in our center we did not have such new mode in our anesthesia machine, so we adjusted the pressure manually to obtain the same volume as PCV-VG did.PCV generates a square pressure waveform with a decelerating inspiratory flow pattern which leads to a more even distribution of VT, recruitment of insufficiently ventilated lung units and oxygenation improvement 14,17,18). Additionally, the rapid alveolar inflation caused by the high initial flow rate in PCV can avoid regional overdistension and lead to better ventilation perfusion matching (19).…”

mentioning

confidence: 99%

Pressure-controlled versus volume-controlled ventilation during one-lung ventilation for video-assisted thoracoscopic lobectomy

Zhu¹,

Fang²,

Ling³

et al. 2017

J. Thorac. Dis.

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Background: It is controversial as to which ventilation mode is better during one-lung ventilation (OLV). This study was designed to figure out whether there was any difference between volume controlled ventilation (VCV) and pressure controlled ventilation (PCV) on oxygenation and postoperative complications under the condition of protective ventilation (PV).Methods: Sixty-five patients undergoing video-assisted thoracoscopic lobectomy were randomized into two groups. Patients in group V received VCV mode during OLV while patients in group P received PCV.The tidal volume (VT) in both groups was 6 mL per predicted body weight (PBW). Positive end-expiratory pressure (PEEP) was set at the level of 5 cmH 2 O in both groups. Arterial gas analysis were performed preoperatively with room air (T 0 ), at 15 mins (T 1 ) and 1 h (T 2 ) after OLV, at the end of OLV (T 3 ), 30 min after PACU admission (T 4 ), 24 h after surgery (post-operative day 1, POD 1 ) and 48 h after surgery (postoperative day 2, POD 2 ). Peak inspiratory airway pressure (Ppeak) and plateau airway pressure (Pplat) were recorded at T 1 , T 2 and T 3 . The perioperative complications were also recorded.Result: Sixty-four patients completed this study. Ppeak in group V was significantly higher than that in group P (T 1 22.3±2.9 vs. 18.7±2.1 cmH 2 O; T 2 22.2±2.8 vs. 18.7±2.6 cmH 2 O). There were no differences with Pplat and intraoperative oxygenation index (T 1 203.3±109.7 vs. 198.1±93.4; T 2 216.8±79.1 vs. 232.1±101.4).The postoperative oxygenation index (T 4 525.0±160.9 vs. 520.7±127.1, post-operative day 1 (POD 1 ) 452.1±161.3 vs. 446.1±109.1; post-operative day 2 (POD 2 ) 403.8±93.4 vs. 396.7±92.8) and postoperative complications were also comparable between these two groups.Conclusions: When they were utilized during OLV, PCV and VCV had the same performance on the intraoperative oxygenation and postoperative complications under the condition of PV. J Thorac Dis 2017;9(5):1303-1309 jtd.amegroups.com ventilation (PCV) with low VT (6 mL/kg) was associated with lower incidence of postoperative lung dysfunction than volume controlled ventilation (VCV) with large VT (10 mL/kg). In 2007, Schultz et al. (5) published recommendations on intraoperative VT and suggested utilizing lower VT (≤6 mL/kg) in patients with abnormal lungs and/or risk factors for ALI.With further studying of small VT ventilation, some new findings came out. Blum et al. (6) showed that the incidence of postoperative ARDS was 0.2% in a general surgical population and the intraoperative risk factor included driver pressure instead of low tide volume. In thoracic surgery, the expected incidence of postoperative ALI was as high as 4.2% (7) and the independent risk factors included intraoperative ventilatory pressure index instead of VT. designed a study to prove their hypothesis that higher VT would be associated with higher risk of respiratory failure secondary to ALI, but the result showed that mean first hour peak airway pressure but not VT was associated with ALI. The clinical resea...

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“…Basınç kontrollü ventilasyon (BKV) ise yoğun bakım ünitelerindeki hipoksik hastalarda özellikle acute Akut Sıkıntılı Solunum sendromu'nda (ARDS) gaz değişimini düzelttiği öne sürülen alternatif bir ventilasyon modudur (5). Basınç kontrollü ventilasyonda alveoller ve proksimal hava yolları arasındaki basınç farkının en fazla olduğu dönem inspiryumun başlangıcındadır.…”

Section: Introductionunclassified

Laparoskopik Kolesistektomi Operasyonlarında Basınç Kontrollü ve Volüm Kontrollü Ventilasyon Modlarının Karşılaştırılması

Şen¹,

İnal²,

Toptaş³

et al. 2014

Haseki

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ÖzetAmaç: Ocak 2011-Ocak 2013 tarihleri arasında gerçekleştirilen laparoskopik kolesistektomi operasyonları sırasında uygulanan Basınç Kontrollü ve Volüm Kontrollü Ventilasyon modlarının hemodinami, solunum mekanikleri ve oksijenizasyona olan etkilerinin anestezi kayıt formlarındaki verileri kullanarak retrospektif analizi amaçlanmıştır. Yöntemler: Retrospektif olarak hasta dosyaları, preoperatif, intraoperatif ve postoperatif anestezi kayıt formları taranarak yapılan çalışmada, Basınç Kontrole Ventilasyon (BKV) modu ile tidal volümü 8-9 mLkg-1 tidal volüm oluşturacak basınç desteği, 12 soluk/dak ve 5 cm H 2 O ile ventile edilmiş olgular Grup 1 (n=41), Volüm Kontrole Ventilasyon (VKV) ile 8-9 mLkg-1 tidal volüm, 12 soluk/dak ve 5 cm H 2 O ile ventile edilmiş olgular Grup 2 (n=41) olarak kaydedildi. Hemodinamik ve solunum mekanikleri, preoperatif dönem, entübasyondan sonrası supin pozisyonunda, CO 2 insuflasyonundan 15-20 dk sonra, desuflasyondan sonra kaydedilmiş parametreler kullanıldı. Aynı dönemlerde ve postoperatif değerlendirilmiş arter kan gazı (AKG) analizleri de kaydedildi. Bulgular: Grup 2'nin insuflasyon dönemi sistolik arter basınç (SAB) değerleri, grup 1'e göre yüksek bulundu. EtCO 2 değerleri açısından gruplar arasında fark yoktu. Grup 2'nin tüm dönemlerdeki P peak değerleri, insuflasyon dönemi P plato değerleri, grup 1'e göre yüksekti. Grup 2'nin tüm dönemlerdeki kompliyans değerleri, grup 1'e göre düşük, desuflasyon dönemi Vd/Vt değerleri ise yüksek bulundu. Grup 2'nin postoperatif derlenme dönemi PaO 2 değerleri, grup 1'e göre düşük, supin dönem Vd/Vt değerleri ise yüksek bulundu. Abs tractAim:The study aimed to carry out a retrospective analysis of the effects of pressure-controlled and volume-controlled ventilation during laparoscopic cholecystectomy procedures performed between January 2011 and January 2013 on hemodynamics, respiratory mechanics and oxygenation. Methods: Data were mainly obtained from preoperative and intraoperative anaesthetic record files. Eighty-two patients, who had undergone laparoscopic cholecystectomy, were retrospectively studied. Group 1 (n=41) received pressure support for obtaining 8-9 mLkg-1 tidal volume with pressurecontrolled ventilation, group 2 (n=41) received volume-controlled ventilation with a tidal volume of 8-9 mLkg-1, a respiratory rate of 12 breaths/min and a positive end-expiratory pressure (PEEP) of 5 cm H 2 O. Hemodynamic and respiratory parameters, which were measured preoperatively, after intubation in the supine position, 15 minutes after CO 2 insufflation, and after desufflation, were recorded. Arterial blood gas analyses were recorded which were measured at the same time with hemodynamics and respiratory parameters and during the postanesthetic care period. Results:Systolic arterial pressure at the time of insufflation was higher in Group 2 than in group 1. There was no difference in EtCO 2 levels between the groups. All times Ppeak and insufflation time P plato levels were higher in group 2. Compliance at all periods was lower in group 2. Desuf...

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Decelerating inspiratory flow waveform improves lung mechanics and gas exchange in patients on intermittent positive-pressure ventilation

Cited by 157 publications

References 28 publications

Different modes of assisted ventilation in patients with acute respiratory failure

Different modes of assisted ventilation in patients with acute respiratory failure

Pressure-controlled versus volume-controlled ventilation during one-lung ventilation for video-assisted thoracoscopic lobectomy

Laparoskopik Kolesistektomi Operasyonlarında Basınç Kontrollü ve Volüm Kontrollü Ventilasyon Modlarının Karşılaştırılması

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