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Singh PM, Borle A, Trikha A. Newer nonconventional modes of mechanical ventilation. J Emerg Trauma Shock 2014; 7:222-7. [PMID: 25114434 PMCID: PMC4126124 DOI: 10.4103/0974-2700.136869] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/29/2013] [Indexed: 11/23/2022] Open
Abstract
The conventional modes of ventilation suffer many limitations. Although they are popularly used and are well-understood, often they fail to match the patient-based requirements. Over the years, many small modifications in ventilators have been incorporated to improve patient outcome. The ventilators of newer generation respond to patient's demands by additional feedback systems. In this review, we discuss the popular newer modes of ventilation that have been accepted in to clinical practice. Various intensive care units over the world have found these modes to improve patient ventilator synchrony, decrease ventilator days and improve patient safety. The various modes discusses in this review are: Dual control modes (volume assured pressure support, volume support), Adaptive support ventilation, proportional assist ventilation, mandatory minute ventilation, Bi-level airway pressure release ventilation, (BiPAP), neurally adjusted ventilatory assist and NeoGanesh. Their working principles with their advantages and clinical limitations are discussed in brief.
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Affiliation(s)
- Preet Mohinder Singh
- Department of Anaesthesia, All India Institute of Medical Sciences, Delhi, India
| | - Anuradha Borle
- Department of Anaesthesia, All India Institute of Medical Sciences, Delhi, India
| | - Anjan Trikha
- Department of Anaesthesia, All India Institute of Medical Sciences, Delhi, India
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Suarez-Sipmann F. New modes of assisted mechanical ventilation. Med Intensiva 2014; 38:249-60. [PMID: 24507472 DOI: 10.1016/j.medin.2013.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 10/22/2013] [Accepted: 10/27/2013] [Indexed: 10/25/2022]
Abstract
Recent major advances in mechanical ventilation have resulted in new exciting modes of assisted ventilation. Compared to traditional ventilation modes such as assisted-controlled ventilation or pressure support ventilation, these new modes offer a number of physiological advantages derived from the improved patient control over the ventilator. By implementing advanced closed-loop control systems and using information on lung mechanics, respiratory muscle function and respiratory drive, these modes are specifically designed to improve patient-ventilator synchrony and reduce the work of breathing. Depending on their specific operational characteristics, these modes can assist spontaneous breathing efforts synchronically in time and magnitude, adapt to changing patient demands, implement automated weaning protocols, and introduce a more physiological variability in the breathing pattern. Clinicians have now the possibility to individualize and optimize ventilatory assistance during the complex transition from fully controlled to spontaneous assisted ventilation. The growing evidence of the physiological and clinical benefits of these new modes is favoring their progressive introduction into clinical practice. Future clinical trials should improve our understanding of these modes and help determine whether the claimed benefits result in better outcomes.
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Affiliation(s)
- F Suarez-Sipmann
- Servicio de Medicina Intensiva, Hospital Universitario de Uppsala, Laboratorio Hedenstierna, Departamento de Ciencias Quirúrgicas, Universidad de Uppsala, Uppsala, Suecia.
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Tobin MJ, Laghi F, Jubran A. Ventilatory failure, ventilator support, and ventilator weaning. Compr Physiol 2013; 2:2871-921. [PMID: 23720268 DOI: 10.1002/cphy.c110030] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The development of acute ventilatory failure represents an inability of the respiratory control system to maintain a level of respiratory motor output to cope with the metabolic demands of the body. The level of respiratory motor output is also the main determinant of the degree of respiratory distress experienced by such patients. As ventilatory failure progresses and patient distress increases, mechanical ventilation is instituted to help the respiratory muscles cope with the heightened workload. While a patient is connected to a ventilator, a physician's ability to align the rhythm of the machine with the rhythm of the patient's respiratory centers becomes the primary determinant of the level of rest accorded to the respiratory muscles. Problems of alignment are manifested as failure to trigger, double triggering, an inflationary gas-flow that fails to match inspiratory demands, and an inflation phase that persists after a patient's respiratory centers have switched to expiration. With recovery from disorders that precipitated the initial bout of acute ventilatory failure, attempts are made to discontinue the ventilator (weaning). About 20% of weaning attempts fail, ultimately, because the respiratory controller is unable to sustain ventilation and this failure is signaled by development of rapid shallow breathing. Substantial advances in the medical management of acute ventilatory failure that requires ventilator assistance are most likely to result from research yielding novel insights into the operation of the respiratory control system.
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Affiliation(s)
- Martin J Tobin
- Division of Pulmonary and Critical Care Medicine, Edward Hines Jr. Veterans Affairs Hospital and Loyola University of Chicago Stritch School of Medicine, Hines, Illinois, USA.
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Delgado M, Zavala E, Tomás R, Fernandez R. Clinical factors associated with success of proportional assist ventilation in the acute phase of critical illness: pilot study. Med Intensiva 2013; 38:65-72. [PMID: 24035698 DOI: 10.1016/j.medin.2013.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Revised: 05/03/2013] [Accepted: 07/09/2013] [Indexed: 10/26/2022]
Abstract
REASON Proportional assist ventilation plus (PAV+) applies pressure depending on the patient's inspiratory effort, automatically adjusting flow and volume assist to changes in respiratory mechanics. We aimed to assess the clinical factors associated with the success of PAV+ as first-line support in the acute phase of critical illness. METHODS A prospective cohort study was carried out. Mechanically ventilated patients>24h were switched from assist-control ventilation to PAV+ as soon as they regained spontaneous breathing activity. PAV+ was set to deliver the highest assistance. We compared patients in whom PAV+ succeeded versus those in whom it failed. RESULTS PAV+ succeeded in 12 (63%) patients, but failed in 7 (37%) due to tachypnea (n=4), hypercapnia (n=2), and metabolic acidosis (n=1), but without statistical significance. Both groups had similar clinical parameters. On the day of inclusion, total work of breathing per breath was lower in the successful PAV+ group (WOBTOT: 0.95 [0.8-1.35] vs. 1.6 [1.4-1.8] J/L; P<.007). The area under the ROC curve was 0.89 ± 0.08 for WOBTOT. The best cut-off for predicting PAV+ success was WOBTOT<1.4 J/L (sensitivity: 1 [0.7-1], specificity: 0.6 [0.4-0.6], PPV: 0.7 [0.5-0.7], and NPV: 1 [0.6-1]). CONCLUSION PAV+ proved feasible as first-line ventilatory support in 63% of the patients, mostly in individuals without extreme derangements in WOBTOT. Tachypnea and hypercapnia were the clinical factors associated with failure, though statistical significance was not reached.
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Affiliation(s)
- M Delgado
- Servicio de Medicina Intensiva, Universitätsklinik für Intensivmedizin, Inselspital, Universitätsspital Bern, Berna, Suiza.
| | - E Zavala
- Sección UCI Quirúrgica, Hospital Clínic, Barcelona, España
| | - R Tomás
- Servicio de Medicina Intensiva, Hospital General de Cataluña, Sant Cugat del Vallès, Barcelona, España
| | - R Fernandez
- Servicio de Medicina Intensiva, Hospital Sant Joan de Déu, Fundació Althaia, Manresa, Barcelona, España; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, España; Universitat Internacional de Catalunya, Barcelona, España
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Abstract
PURPOSE OF REVIEW New developments in mechanical ventilation have focused on increasing the patient's control of the ventilator by implementing information on lung mechanics and respiratory drive. Effort-adapted modes of assisted breathing are presented and their potential advantages are discussed. RECENT FINDINGS Adaptive support ventilation, proportional assist ventilation with load adjustable gain factors and neurally adjusted ventilatory assist are ventilatory modes that follow the concept of adapting the assist to a defined target, instantaneous changes in respiratory drive or lung mechanics. Improved patient ventilator interaction, sufficient unloading of the respiratory muscles and increased comfort have been recently associated with these ventilator modalities. There are, however, scarce data with regard to outcome improvement, such as length of mechanical ventilation, ICU stay or mortality (commonly accepted targets to demonstrate clinical superiority). SUMMARY Within recent years, a major step forward in the evolution of assisted (effort-adapted) modes of mechanical ventilation was accomplished. There is growing evidence that supports the physiological concept of closed-loop effort-adapted assisted modes of mechanical ventilation. However, at present, the translation into a clear outcome benefit remains to be proven. In order to fill the knowledge gap that impedes the broader application, larger randomized controlled trials are urgently needed. However, with clearly proven drawbacks of conventional assisted modes such as pressure support ventilation, it is probably about time to leave these modes introduced decades ago behind.
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Costa R, Spinazzola G, Cipriani F, Ferrone G, Festa O, Arcangeli A, Antonelli M, Proietti R, Conti G. A physiologic comparison of proportional assist ventilation with load-adjustable gain factors (PAV+) versus pressure support ventilation (PSV). Intensive Care Med 2011; 37:1494-500. [DOI: 10.1007/s00134-011-2297-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 06/08/2011] [Indexed: 10/18/2022]
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Trabajo y patrón respiratorio con diferentes niveles de ventilación asistida proporcional. Med Intensiva 2009; 33:269-75. [DOI: 10.1016/s0210-5691(09)72194-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 12/22/2008] [Indexed: 11/22/2022]
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Sinderby C, Beck J. Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist—Better Approaches to Patient Ventilator Synchrony? Clin Chest Med 2008; 29:329-42, vii. [DOI: 10.1016/j.ccm.2008.01.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Mirkovic T, Paver-Erzen V, Klokocovnik T, Gursahaney A, Hernandez P, Gottfried SB. Tracheal pressure regulated volume assist ventilation in acute respiratory failure. Can J Anaesth 2007; 54:420-9. [PMID: 17541070 DOI: 10.1007/bf03022027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Proportional assist ventilation (PAV) uses volume assist (VAV) and flow assist ventilation (FAV) to reduce elastic and resistive effort, respectively. Proportional assist ventilation may be difficult to apply clinically, particularly due to FAV related considerations. It was hypothesized that regulating tracheal (Ptr) rather than airway opening pressure (Pao), to overcome endotracheal tube related resistive effort, during VAV would provide an effective alternative method of ventilation. We therefore compared the effects of Pao and Ptr regulated VAV on breathing pattern and inspiratory effort. METHODS In seven intubated patients, flow, volume, Pao, Ptr, esophageal and transdiaphragmatic pressure were measured during VAV (0-80% respiratory system elastance) using Pao vs Ptr to regulate ventilator applied pressure. Breathing pattern and the pressure-time integral of the inspiratory muscles (integralP(mus) . dt) and diaphragm (integralP(di) . dt) were determined. RESULTS Compared to spontaneous breathing, the respiratory rate to tidal volume ratio, or rapid shallow breathing index (RSBI), improved progressively with increasing VAV (130 +/- 64 vs 70 +/- 35, VAV 0 vs 80%; P < 0.05) while inspiratory effort fell (integralP(mus) . dt = 39.6 +/- 7.5 vs 28.5 +/- 7.2 cm H(2)O.sec.L(-1), integralP(di) . dt, = 35.4 +/- 7.8 vs 24.2 +/- 5.9 cm H(2)O.sec.L(-1), VAV 0 vs 80%; P < 0.05) due to a decrease in elastic related effort. At any given level of support, there was further reduction in RSBI, integralP(mus) . dt, and integralP(di) . dt (which averaged 23.6 +/- 2.7, 33.7 +/- 4.4, and 38.5 +/- 5.1%, respectively; P < 0.05) for Ptr compared to Pao regulated VAV due to a decrease in resistive effort. CONCLUSIONS Tracheal pressure regulated VAV can be a simple and effective method of partial ventilatory support in acute respiratory failure. Further work will be needed to determine its efficacy and potential benefit relative to PAV and other modes of ventilation in routine clinical practice.
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Affiliation(s)
- Tomislav Mirkovic
- McGill University Health Centre, Royal Victoria Hospital, 687 Pine Avenue West, Room M4.10, Montreal, Quebec H3A 1A1, Canada.
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Jolliet P, Tassaux D. Clinical review: patient-ventilator interaction in chronic obstructive pulmonary disease. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2007; 10:236. [PMID: 17096868 PMCID: PMC1794446 DOI: 10.1186/cc5073] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mechanically ventilated patients with chronic obstructive pulmonary disease often prove challenging to the clinician due to the complex pathophysiology of the disease and the high risk of patient-ventilator asynchrony. These problems are encountered in both intubated patients and those ventilated with noninvasive ventilation. Much knowledge has been gained over the years in our understanding of the mechanisms underlying the difficult interaction between these patients and the machines used to provide them with the ventilatory support they often require for prolonged periods. This paper attempts to summarize the various key issues of patient-ventilator interaction during pressure support ventilation, the most often used partial ventilatory support mode, and to draw clinicians' attention to the need for sufficient knowledge when setting the ventilator at the bedside, given the often conflicting goals that must be met.
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Affiliation(s)
- Philippe Jolliet
- Intensive Care, University Hospital, 1211 Geneva 14, Switzerland.
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Kondili E, Xirouchaki N, Georgopoulos D. Modulation and treatment of patient–ventilator dyssynchrony. Curr Opin Crit Care 2007; 13:84-9. [PMID: 17198054 DOI: 10.1097/mcc.0b013e328011278d] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW The coupling between ventilator delivered inspiratory flow and patient's demands both in terms of timing and drive is a challenging task that has become largely feasible in recent years. This review addresses the new advances to modulate and treat patient-ventilator dyssynchrony. RECENT FINDINGS Patient-ventilator dyssynchrony is a common phenomenon with conventional modes of mechanical ventilation which influence the duration of mechanical ventilation. Inspection of pressure, volume and flow waveforms represents a valuable tool for the physician to recognize and take the appropriate action to improve patient-ventilator synchrony. New developments have been introduced aiming to improve patient ventilator synchrony by modulating the triggering function and the variables that control the flow delivery and the cycling off. SUMMARY Patient-ventilator dyssynchrony may affect patients' outcome. New modes of assisted mechanical ventilation have been introduced and represent a major step forward in modulating patient-ventilator dyssynchrony.
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Affiliation(s)
- Eumorfia Kondili
- Intensive Care Medicine Department, University Hospital of Heraklion, University of Crete, Medical School, Heraklion, Crete, Greece.
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Georgopoulos D, Prinianakis G, Kondili E. Bedside waveforms interpretation as a tool to identify patient-ventilator asynchronies. Intensive Care Med 2005; 32:34-47. [PMID: 16283171 DOI: 10.1007/s00134-005-2828-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Accepted: 09/08/2005] [Indexed: 11/30/2022]
Abstract
OBJECTIVE During assisted modes of ventilatory support the ventilatory output is the final expression of the interaction between the ventilator and the patient's controller of breathing. This interaction may lead to patient-ventilator asynchrony, preventing the ventilator from achieving its goals, and may cause patient harm. Flow, volume, and airway pressure signals are significantly affected by patient-ventilator interaction and may serve as a tool to guide the physician to take the appropriate action to improve the synchrony between patient and ventilator. This review discusses the basic waveforms during assisted mechanical ventilation and how their interpretation may influence the management of ventilated patients. The discussion is limited on waveform eye interpretation of the signals without using any intervention which may interrupt the process of mechanical ventilation. DISCUSSION Flow, volume, and airway pressure may be used to (a) identify the mode of ventilator assistance, triggering delay, ineffective efforts, and autotriggering, (b) estimate qualitatively patient's respiratory efforts, and (c) recognize delayed and premature opening of exhalation valve. These signals may also serve as a tool for gross estimation of respiratory system mechanics and monitor the effects of disease progression and various therapeutic interventions. CONCLUSIONS Flow, volume, and airway pressure waveforms are valuable real-time tools in identifying various aspects of patient-ventilator interaction.
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Affiliation(s)
- Dimitris Georgopoulos
- Intensive Care Medicine Department, University Hospital of Heraklion, University of Crete, Heraklion, Crete, Greece.
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Abstract
PURPOSE OF REVIEW To review the changes in mechanical ventilation technology over the past year and identify areas that provide a benefit. RECENT FINDINGS The literature demonstrates a continued effort to improve patient ventilator synchrony though the development of new triggering and cycling methods. These techniques include using new signals and using closed loop techniques to respond to changes in patient breathing pattern. New modes of ventilation continue to be introduced, often without proof of efficacy. Fortunately, clinicians have developed alterations to new modes that improve utility and they continue to study these techniques clinically to determine appropriate use. Monitoring the patient remains an important area of investigation, with a flurry of activity surrounding pressure volume curves of the respiratory system. Finally, new ventilators have been introduced that combine high-end performance with small size and weight, while providing an on-board source of air. SUMMARY Mechanical ventilation is ubiquitous to intensive care. Advances in ventilator technology are rapid, and clinicians must keep abreast of changes in ventilator performance and application.
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Affiliation(s)
- Richard Branson
- Department of Surgery, Division of Trauma & Critical Care, University of Cincinnati, Cincinnati, Ohio, USA.
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Affiliation(s)
- E Kondili
- Department of Intensive Care, University Hospital, University of Crete, School of Medicine, Heraklion, Greece
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Affiliation(s)
- Martin J Tobin
- Division of Pulmonary and Critical Care Medicine, Loyola University of Chicago Stritch School of Medicine and Hines Veterans Affairs Hospital, Hines, Illinois 60141, USA.
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Navalesi P, Costa R. New modes of mechanical ventilation: proportional assist ventilation, neurally adjusted ventilatory assist, and fractal ventilation. Curr Opin Crit Care 2003; 9:51-8. [PMID: 12548030 DOI: 10.1097/00075198-200302000-00010] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Increased knowledge of the mechanisms that determine respiratory failure has led to the development of new technologies aimed at improving ventilatory treatment. Proportional assist ventilation and neurally adjusted ventilatory assist have been designed with the goal of improving patient-ventilator interaction by matching the ventilator support with the neural output of the respiratory centers. With proportional assist ventilation, the support is continuously readjusted in proportion to the predicted inspiratory effort. Neurally adjusted ventilatory assist is an experimental mode in which the assistance is delivered in proportion to the electrical activity of the diaphragm, assessed by means of an esophageal electrode. Biologically variable (or fractal) ventilation is a new, volume-targeted, controlled ventilation mode aimed at improving oxygenation; it incorporates the breath-to-breath variability that characterizes a natural breathing pattern.
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Affiliation(s)
- Paolo Navalesi
- Pneumologia e Terapia Intensiva Respiratoria, Fondazione S. Maugeri, Pavia, Italy.
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Respiratory Muscle Unloading during Mechanical Ventilation. Intensive Care Med 2003. [DOI: 10.1007/978-1-4757-5548-0_27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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