Principles Of Mechanical Ventilation Research Articles

Basics of mechanical ventilation for non-anaesthetists. Part 1: Theoretical aspects.

The expanding number of chronic respiratory diseases and the new Covid-19 outbreak create an increasing demand for mechanical ventilation (MV). As MV is no longer limited to intensive care units (ICU) and operating rooms (OR), more clinicians should acquaint themselves with the principles of mechanical ventilation. To fully acknowledge contemporary concepts of MV, it is crucial to understand the elemental physiology and respiratory machine nuances. This paper addresses the latter issues and provides insight into ventilation modes and essential monitoring of MV.

BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults

### Principles of mechanical ventilation #### Modes of mechanical ventilation Recommendation 1. Pressure-targeted ventilators are the devices of choice for acute NIV (Grade B). Good practice points #### Choice of...

How to nurse the intensive care unit ventilator patient

Mechanical ventilators are an integral part of any intensive care unit. There are a variety of patients that may benefit from mechanical ventilation such as patients that are hypoxaemic (Pa02 <60mmHg) in spite of oxygen therapy, hypercapnic (PaC02>60mmHg) or at risk of impending respiratory failure. Mechanical ventilation is expensive and requires a dedicated nurse to care for the patient. This nurse must have an understanding of respiratory physiology, principles of mechanical ventilation, terminology, setting up the ventilator, troubleshooting problems, providing nursing care to meet the individual patient requirements and recognising signs of complications. Such cases require thorough clinical records and communication between staff members. They are labour intensive cases but can be extremely rewarding to nurse.

Critical Care Handbook of the Massachusetts General Hospital, Fifth Edition.

University of Toledo, Toledo, Ohio. kimberly.jenkins2@utoledo.eduCritical Care Handbook of the Massachusetts General Hospital, Fifth Edition. Edited by Luca M. Bigatello, M.D., Hasan Alam, M.D., Rae M. Allain, M.D., Edward A. Bittner, M.D., Ph.D., Dean Hess, Ph.D., R.R.T., Richard M. Pino, M.D., Ph.D., Ulrich Schmidt, M.D., Ph.D. Philadelphia, Lippincott, Williams & Wilkins, 2010. Pages: 752. ISBN-10: 0781795664. ISBN-13: 978-0-7817-9566-1. Price: $57.95.Covering the essentials of critical care, the Critical Care Handbook of the Massachusetts General Hospital, Fifth Edition , serves as a multidisciplinary expert review of the general principles and specific considerations in taking care of the critically ill patient.This fifth edition is organized into two major sections. The first, with 16 chapters, explores general principles of critical care, including hemodyamic and respiratory monitoring, nutritional support, fluids and electrolytes, airway management, and principles of mechanical ventilation. The second section, with 28 chapters, covers more evidence-based specific management of systemic diseases, including renal failure, chronic obstructive pulmonary disease, and coronary artery disease.The opening chapters provide an outline strategy for grasping the fundamentals of critical care. The outline format provides a simple review of the most commonly found problems in the intensive care unit. The chapter on hemodynamic monitoring is an especially useful and relevant review of the interpretation of data based on the application of basic circulatory physiology. The clear and concise chapters provide enough valuable insight to be practically useful at the bedside without providing more bulk than is needed in a manual format. The emphasis on practicality is again in evidence in the chapter on the use of ultrasound in the intensive care unit, in which a clear overview of the uses and limitations of point-of-care ultrasound and echocardiography in such units is provided. A brief review of ultrasound physics is given in addition to several figures comparing normal and pathologic anatomy.The transverse view of the right internal jugular vein and carotid artery juxtaposed with a longitudinal view is precisely the type of bedside practical and tangible expertise needed before performing ultrasound-guided central line placement. The first section of this manual is filled with chapters providing clear figures, black-and-white illustrations, and tables of high quality. The practical outline form provides easy navigation of the material and would make this a favorite of the novice as well as the seasoned intensivist.The second section of the book looks specifically at 28 areas of specific systemic management. This serves as a quick review of the pathophysiology involved and then directly addresses diagnostic and therapeutic goals. In the pulmonary embolism and deep vein thrombosis chapter, the management was particularly useful as the complications and contraindications of therapy were clearly outlined. The manual frequently provides the evidence that exists behind the recommendations given in these latter chapters. Where original work is not cited, pertinent reviews are indicated. Concluding is a useful appendix listing supplemental drugs commonly used, including their indications, dosage, effect, onset and duration, clearance, and any additional recommendations. Chapters are succinct, with clear discussion and summary points concluding each presentation.This is an excellent overview manual of critical care. I strongly recommend this book as a valuable addition to the library of anyone who practices intensive care medicine and would appreciate a critical care manual that provides thorough, direct, and up-to-date management recommendations.University of Toledo, Toledo, Ohio. kimberly.jenkins2@utoledo.edu

How Much PEEP in Acute Lung Injury

ACUTE LUNG INJURY (ALI) IS A COMMON, LETHAL, AND complex syndrome. Estimates of attributable mortality from ALI or its more severe form, acute respiratory distress syndrome (ARDS), in the United States place it above asthma and human immunodeficiency virus infection as a cause of death. The current mortality of 35% associated with ALI is roughly 3-fold higher than that associated with ST-segment elevation myocardial infarction. Most of the salient features of ARDS, including the therapeutic use of positive end-expiratory pressure (PEEP), were described by Ashbaugh et al in their classic description of the syndrome: “ventilation without positive end-expiratory pressure resulted in immediate hypoxaemia. . . . Collapsed alveoli require greater pressures for reopening, thus explaining the notable loss of compliance. Positive end-expiratory pressure would theoretically prevent complete collapse and improve oxygenation by maintaining alveolar ventilation.” Ashbaugh et al thought that mechanical ventilation merely prevented hypoxemic death, thereby providing clinicians with time to treat the underlying cause of ARDS. However, recent research has focused on the degree to which mechanical ventilation is injurious, depending on how it is applied, by causing inflammation and multiple organ failure. There is little disagreement about the principles of mechanical ventilation in patients with ALI: a PEEP sufficient to recruit collapsed lung areas should be used while delivering small tidal volumes to protect the uninjured lung from overdistention. These basic concepts do not provide any of the details required to manage the care of patients at the bedside. Although the use of PEEP is a simple physiological intervention, it has potentially deleterious effects on right and left ventricular function, pulmonary vascular resistance, and thoracic compliance, leading to unpredictable effects on gas exchange and hemodynamics in individual patients. Airway pressures necessary to recruit collapsed lung areas can improve oxygenation but also can overdistend normal areas of pulmonary parenchyma, worsen inflammation, and reduce cardiac output. Therefore, identifying the optimal PEEP to use in ALI has been the focus of a substantial amount of clinical investigation. Many strategies exist: clinicians can increase PEEP to achieve the maximal improvement in oxygenation, sacrificing overdistention of normal alveoli; balance oxygenation benefits against cardiac output or blood pressure; use pressure-volume curves or dynamic stress indices to identify a trade-off point of lung recruitment; or use sophisticated imaging techniques to assess how much lung has been opened. However, in clinical practice, patients with ALI do not appear to benefit from any of these strategies. Large cohorts of patients receiving mechanical ventilation show that patients with ALI, ARDS, acute respiratory failure that is neither ALI nor ARDS, and patients with chronic obstructive pulmonary disease all receive, on average, about 8 cm H2O of PEEP. Current practice may reflect the lack of evidence demonstrating a patient-centered outcome benefit of any specific approach to titrating PEEP. Four recent clinical trials address the question of “How much PEEP in acute lung injury?”: ALVEOLI, LOVS, EXPRESS, and EPVENT. All of these investigations were designed to measure the benefits of a protocolized higher PEEP strategy in a broad range of patients with ALI receiving tidal volumes thought to be protective. The protocols tested were related only in that they delivered approximately 14.5 to 18 cm H2O of PEEP on day 1 to patients in the intervention groups. The usual set of explanations were invoked to interpret the results of high-quality, wellconceived, but statistically negative trials; ie, the wrong patients were enrolled; too few patients were enrolled because of overly optimistic projections of the effect of PEEP on mortality; and unlucky randomization led to sicker patients in the intervention groups and to investigators not using the right approach to setting PEEP. In this issue of JAMA, a meta-analysis of individualpatient data by Briel and colleagues addresses 3 of these 4 important limitations. Using primary data from the actual trials, the authors demonstrated that, after adjusting for individual patient covariates, higher PEEP was associated with

Principles of mechanical ventilation – a critical review

This article is the first of a two-part review focusing on mechanical ventilation, with particular emphasis on non-invasive ventilation when managing patients suffering from respiratory failure. This article explores the principles underpinning artificial ventilation, explains the difference between positive and negative pressure ventilation, and differentiates between invasive and non-invasive modes of ventilation. Finally it examines the various operational features, flexibility in use and limitations that artificial ventilation therapy presents. Optimum ventilatory practice requires knowledge to ensure the choosing of the 'right' ventilator. It ensures informed practice and maintains optimum patient safety.

New strategies in mechanical ventilation for acute lung injury.

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 CO2 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.

Physiological principles of mechanical ventilation of the newborn.

Physiological principles of mechanical ventilation of the newborn.

Cardiopulmonary Critical Care.

Section I: Pathophysiology. Pathogenesis of Acute Lung Injury. Pulmonary Gas Exchange. Pathophysiology of the Pulmonary Vascular Bed. Mechanical Cardiopulmonary Interactions in Critical Care. Peripheral Control of Venous Return in Critical Illness Role of the Splanchnic Vascular Compartment. The Muscles of Respiration. Cardiac Function. Oxygen Transport and Utilization. The Microcirculation and Tissue Oxygenation. Pulmonary Mechanics in Critical Care. Section II: Principles of Treatment. Principles of Mechanical Ventilation and Weaning. Ventilatory Control in the Critical Care Setting. Critical Care Radiology. Cardiopulmonary Resuscitation. Pharmacologic and Ventilatory Support of the Circulation in Critically Ill Patients. Section III: Specific Disorders. Acute Myocardial Infarction. Cardiac Rhythm Disorders in the Critical Care Setting: Pathophysiology, Diagnosis, And Management. Acute Respiratory Distress Syndrome. Heart-Lung Interactions in Sepsis. Community-Acquired Pneumonia. Hospital-Acquired Pneumonia and Pneumonia in the Immunosuppressed Host. Deep Venous Thrombosis and Pulmonary Embolism. Status Asthmaticus. Chronic Obstructive Pulmonary Disease. Smoke Inhalation Injury. Hyperbaric Medicine. Cardiorespiratory Failure Caused By High Altitude.

Introduction to Life Support.

This paperback book stems from a teaching manual designed to introduce second-year medical students to the principles of emergency medical care. The 14 chapters were written by 16 authors, most of whom are from the department of anesthesiology at the University of Florida College of Medicine. The cornerstone of the book is in the early chapters on emergency airway control and ventilation and cardiopulmonary resuscitation. The material is clearly presented and its brevity is an asset in making the various points easy to understand. There is some repetition in other chapters. The chapter on principles of mechanical ventilation provides an excellent summary of the various ventilators available and the basic principle of respiratory care. Another useful section discussed in the chapter on acid-base regulation, relates to in vivo changes in pH and [HCO₃] under variations of arterial carbon dioxide pressure. At this time, there has been renewed interest in