Search Our Scientific Publications & Authors

Eur Respir Rev 2022 Mar 9;31(163). Epub 2022 Feb 9.

Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia.

Recently, "Technical standards for respiratory oscillometry" was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. Read More

Clin Perinatol 2021 12 2;48(4):869-880. Epub 2021 Oct 2.

NICU, 4(th) floor Golden Jubilee Wing, King's College Hospital NHS Foundation Trust, Denmark Hill, London, SE5 9RS, UK; Asthma UK Centre for Allergic Mechanisms in Asthma, London, SE9 0RT, UK; NIHR Biomedical Research Centre Based at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, SE9 0RT, UK. Electronic address:

Mechanical ventilation can be life-saving for the premature infant, but is often injurious to immature and underdeveloped lungs. Lung injury is caused by atelectrauma, oxygen toxicity, and volutrauma. Lung protection must include appropriate lung recruitment starting in the delivery suite and throughout mechanical ventilation. Read More

Int J Emerg Med 2021 Sep 22;14(1):58. Epub 2021 Sep 22.

Department of Critical Care, St. John's Medical College, Bangalore, 560034, India.

Background: Patients with acute respiratory failure, impaired consciousness, and impaired airway reflexes will require invasive mechanical ventilation. Monitoring of such patients is important. The use of ventilator scalars and loops help in monitoring, diagnosing the abnormality, and treating the patients effectively. Read More

Pediatr Pulmonol 2021 07 18;56(7):2102-2107. Epub 2021 Apr 18.

Department of Pediatrics, National Hospital Organization Maizuru Medical Center, Maizuru, Kyoto, Japan.

Background: Ventilated neonates with hypoxemic respiratory failure (HRF) may show a ventilation-perfusion (V/Q) mismatch.

Objective: To evaluate the difference between the Bohr (V ) and Enghoff (V ) dead spaces in infants by using volumetric capnography based on ventilator graphics and capnograms.

Methods: This study enrolled 46 ventilated infants (mean birth weight, 2239 ± 640 g; mean gestational age, 35. Read More

J Intensive Care Med 2021 Jun 11;36(6):696-703. Epub 2021 Mar 11.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, 21782University of Iowa Hospitals and Clinics, Iowa City, IA, USA.

Objective: Many patients with coronavirus disease 2019 (COVID-19) need mechanical ventilation secondary to acute respiratory distress syndrome. Information on the respiratory system mechanical characteristics of this disease is limited. The aim of this study is to describe the respiratory system mechanical properties of ventilated COVID-19 patients. Read More

Curr Pediatr Rep 2021 5;9(1):11-19. Epub 2021 Jan 5.

Department of Pediatrics, Division of Pediatric Critical Care Medicine, Medical University of South Carolina, 125 Doughty Street, MSC 917, Charleston, SC 29425 USA.

Purpose Of Review: Knowledge of ventilator waveforms is important for clinicians working with children requiring mechanical ventilation. This review covers the basics of how to interpret and use data from ventilator waveforms in the pediatric intensive care unit.

Recent Findings: Patient-ventilator asynchrony (PVA) is a common finding in pediatric patients and observed in approximately one-third of ventilator breaths. Read More

Acute Crit Care 2020 Aug 31;35(3):131-141. Epub 2020 Aug 31.

Lane Fox Respiratory Service, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, London, UK.

Over recent decades, the use of home mechanical ventilation (HMV) has steadily increased worldwide, with varying prevalence in different countries. The key indication for HMV is chronic respiratory failure with alveolar hypoventilation (e.g. Read More

Eur J Pediatr 2021 Jan 3;180(1):241-246. Epub 2020 Aug 3.

Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502, Japan.

Hypercapnia occurs in ventilated infants even if tidal volume (V) and minute ventilation (V) are maintained. We hypothesised that increased physiological dead space (V) caused decreased minute alveolar ventilation (V; alveolar ventilation (V) × respiratory rate) in well-ventilated infants with hypercapnia. We investigated the relationship between dead space and partial pressure of carbon dioxide (PaCO) and assessed V. Read More

Respir Care 2020 Jun;65(6):739-759

Department of Kinesiology, Respiratory Care Program, University of North Carolina at Charlotte, Charlotte, North Carolina.

Ventilator graphic monitoring is common in ICUs. The graphic information provides clinicians with immediate clues regarding patient-ventilator interaction and ventilator function. These display tools are aimed at reducing complications associated with mechanical ventilation, such as patient-ventilator asynchrony. Read More

Heart Lung 2020 Sep - Oct;49(5):630-636. Epub 2020 Apr 30.

College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia; Intensive Care Department, Ministry of the National Guard, Health Affairs, Riyadh, Saudi Arabia.

Background: Patient-ventilator asynchrony (PVA) is a prevalent and often underrecognized problem in mechanically ventilated patients. Ventilator waveform analysis is a noninvasive and reliable means of detecting PVAs, but the use of this tool has not been broadly studied.

Methods: Our observational analysis leveraged a validated evaluation tool to assess the ability of critical care practitioners (CCPs) to detect different PVA types as presented in three videos. Read More

Neonatology 2020 11;117(2):189-192. Epub 2019 Dec 11.

Department of Pediatrics, National Hospital Organization Maizuru Medical Center, Kyoto, Japan.

Background: Few studies have reported the measurement of anatomical dead space (Vd,an) and alveolar tidal volume (VA) in ventilated neonates with respiratory distress.

Objective: The aim of this study was to determine the differences in Vd,an and VA in ventilated infants between the early and recovery phases of respiratory distress using volumetric -capnography (Vcap) based on ventilator graphics and capnograms.

Methods: This study enrolled twenty-five ventilated infants (mean birth weight, 2,220 ± 635 g; mean gestational age, 34. Read More

Acta Biomed 2018 12 7;89(7-S):6-18. Epub 2018 Dec 7.

Fondazione Poliambulanza Hospital, Brescia (Italy).

Background: Mechanical ventilation is often employed as partial ventilatory support where both the patient and the ventilator work together. The ventilator settings should be adjusted to maintain a harmonious patient-ventilator interaction. However, this balance is often altered by many factors able to generate a patient ventilator asynchrony (PVA). Read More

J Intensive Care Med 2018 Sep 5;33(9):491-501. Epub 2017 Nov 5.

2 Department of Critical Care, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.

The management of the critically ill patients with asthma can be rather challenging. Potentially devastating complications relating to this presentation include hypoxemia, worsening bronchospasm, pulmonary aspiration, tension pneumothorax, dynamic hyperinflation, hypotension, dysrhythmias, and seizures. In contrast to various other pathologies requiring mechanical ventilation, acute asthma is generally associated with better outcomes. Read More

J Crit Care 2018 Feb 6;43:169-182. Epub 2017 Sep 6.

Department of Pulmonary and Critical Care Medicine, Tokyo Bay Urayasu Ichikawa Medical Center, 3-4-32 Todaijima, Urayasu City, Chiba 2790001, Japan.

Pressure controlled ventilation is a common mode of ventilation used to manage both adult and pediatric populations. However, there is very little evidence that distinguishes the efficacy of pressure controlled ventilation over that of volume controlled ventilation in the adult population. This gap in the literature may be due to the absence of a consistent and systematic algorithm for managing pressure controlled ventilation. Read More

J Crit Care 2017 10 18;41:112-118. Epub 2017 Apr 18.

Department of Emergency and Critical Care Medicine, St. Marianna University Hospital, Kanagawa, Japan.

Purpose: This study investigated the effects of physician education and the availability of P and P data on physicians' decisions regarding ventilator management during specific simulated clinical conditions.

Materials And Methods: The study was a prospective, before-after study using a case scenario-based questionnaire and a case simulator device comprising an Avea ventilator and an artificial lung and esophagus, which was connected to a Series 1101 Electronic Breathing Simulator. The 99 physicians participating in the study were provided with five simulated cases with on-time ventilator graphics without P and P and completed a questionnaire on decisions they would make regarding ventilator management of the cases. Read More

Respir Care 2017 Feb 25;62(2):144-149. Epub 2016 Oct 25.

Department of Respiratory Care, University of Texas Health Sciences Center at San Antonio, San Antonio, Texas.

Background: Waveform analysis by visual inspection can be a reliable, noninvasive, and useful tool for detecting patient-ventilator asynchrony. However, it is a skill that requires a properly trained professional.

Methods: This observational study was conducted in 17 urban ICUs. Read More

Clin Chest Med 2016 Dec 14;37(4):669-681. Epub 2016 Oct 14.

Respiratory Care Services, Duke University Hospital, Box 3911 Duke North, Erwin Road, Durham, NC 27710, USA.

Ventilatory muscle fatigue is a reversible loss of the ability to generate force or velocity of contraction in response to increased elastic and resistive loads. Mechanical ventilation should provide support without imposing additional loads from the ventilator (dys-synchrony). Interactive breaths optimize this relationship but require that patient effort and the ventilator response be synchronous during breath initiation, flow delivery, and termination. Read More

Clin Chest Med 2016 Dec;37(4):615-632

Universidad Catolica de Chile, 328 Avenida Libertador Bernardo O' Higgins, Santiago de Chile, Chile.

The main goals of assessing respiratory system mechanical function are to evaluate the lung function through a variety of methods and to detect early signs of abnormalities that could affect the patient's outcomes. In ventilated patients, it has become increasingly important to recognize whether respiratory function has improved or deteriorated, whether the ventilator settings match the patient's demand, and whether the selection of ventilator parameters follows a lung-protective strategy. Ventilator graphics, esophageal pressure, intra-abdominal pressure, and electric impedance tomography are some of the best-known monitoring tools to obtain measurements and adequately evaluate the respiratory system mechanical function. Read More

Minerva Pediatr 2016 Dec 8;68(6):456-469. Epub 2016 Jul 8.

Section of Critical Care, Department of Pediatrics, University of Alabama, Birmingham, AL, USA -

Providing optimal mechanical ventilation to critically-ill children remains a challenge. Patient-ventilator dyssynchrony results frequently with numerous deleterious consequences on patient outcome including increased requirement for sedation, prolonged duration of ventilation, and greater imposed work of breathing. Most currently used ventilators have real-time, continuously-displayed graphics of pressure, volume, and flow versus time (scalars) as well as pressure, and flow versus volume (loops). Read More

Semin Fetal Neonatal Med 2015 Jun 7;20(3):181-91. Epub 2015 Feb 7.

Department of Pediatrics, Division of Neonatal-Perinatal Medicine, C.S. Mott Children's Hospital, University of Michigan Health System, Ann Arbor, MI, USA.

Real-time pulmonary graphics now enable clinicians to view lung mechanics and patient-ventilator interactions on a breath-to-breath basis. Displays of pressure, volume, and flow waveforms, pressure-volume and flow-volume loops, and trend screens enable clinicians to customize ventilator settings based on the underlying pathophysiology and responses of the individual patient. This article reviews the basic concepts of pulmonary graphics and demonstrates how they contribute to our understanding of respiratory physiology and the management of neonatal respiratory failure. Read More

J Pediatr 2014 Nov 12;165(5):1064. Epub 2014 Aug 12.

Department of Pediatrics, Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island.

Niger Med J 2014 Jul;55(4):359-61

Department of Neuroanesthesia and Neurocritical Care, All India Institute of Medical Sciences, New Delhi, India.

The importance of ventilator graphics cannot be over emphasized that provide the useful information about airway, ventilation, compliance and lung mechanics. Some bizarre forms of graphics are usually overlooked in view of artifacts, but sometimes these tracings may in fact predict some relevant information. Read More

J Clin Monit Comput 2014 Dec 19;28(6):613-23. Epub 2014 Feb 19.

Division for Experimental Anesthesiology, Department of Anesthesiology, University Medical Center Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany,

In mechanical ventilation, a careful setting of the ventilation parameters in accordance with the current individual state of the lung is crucial to minimize ventilator induced lung injury. Positive end-expiratory pressure (PEEP) has to be set to prevent collapse of the alveoli, however at the same time overdistension should be avoided. Classic approaches of analyzing static respiratory system mechanics fail in particular if lung injury already prevails. Read More

Top Companion Anim Med 2013 Aug;28(3):112-23

Small Animal Emergency and Critical Care Service, Department of Veterinary Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA. Electronic address:

Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). Read More

Annu Int Conf IEEE Eng Med Biol Soc 2013 ;2013:465-8

The application of mechanical ventilation is a life-saving routine therapy that allows the patient to overcome the physiological impact of surgeries, trauma or critical illness by ensuring vital oxygenation and carbon dioxide removal. Above a certain level of minute ventilation (usually set to ensure acceptable carbon dioxide removal and oxygenation) oxygenation is only marginally affected by a further increase in minute ventilation. Thus, oxygenation is predominantly influenced by inspiratory oxygen fraction (FiO2) Usually, finding the appropriate setting is a trial-and-error procedure, as the clinician is unaware of the exact value that needs to be set in order to reach the desired arterial oxygen partial pressures (PaO2) in the patient. Read More

Am J Respir Crit Care Med 2013 Nov;188(9):1058-68

1 Department of Medicine, Duke University, Durham, North Carolina.

Assisted/supported modes of mechanical ventilation offer significant advantages over controlled modes in terms of ventilator muscle function/recovery and patient comfort (and sedation needs). However, assisted/supported breaths must interact with patient demands during all three phases of breath delivery: trigger, target, and cycle. Synchronous interactions match ventilator support with patient demands; dyssynchronous interactions do not. Read More

Chin Med J (Engl) 2013 ;126(17):3396

Department of Respiratory Therapy, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China.

J Vet Emerg Crit Care (San Antonio) 2011 Oct;21(5):496-514

Critical Care Department at Florida Veterinary Specialists, Busch Lake Blvd, Tampa, FL 33614, USA.

Objective: To review the topic of ventilator waveforms analysis with emphasis on interpretation of ventilator waveforms and their use in the management and monitoring of mechanically ventilated small animal patients.

Data Sources: Human clinical studies, scientific reviews, and textbooks, as well as veterinary textbooks and clinical examples of ventilator waveforms in mechanically ventilated dogs.

Summary: Ventilator waveforms are graphic representations of data collected from the ventilator and reflect patient-ventilator interactions. Read More

Respir Care 2011 Feb;56(2):214-28

Department of Respiratory Care, University of Washington, Seattle, WA, USA.

Patient-ventilator interaction has been the focus of increasing attention from both manufacturers and researchers during the last 25 years. There is now compelling evidence that passive (controlled) mechanical ventilation leads to respiratory muscle dysfunction and atrophy, prolonging the need for ventilatory support and predisposing to a number of adverse patient outcomes. Although there is consensus that the respiratory muscles should retain some activity during acute respiratory failure, patient-ventilator asynchrony is now recognized as a cause of ineffective ventilation, impaired gas exchange, lung overdistention, increased work of breathing, and patient discomfort. Read More

Respir Care 2011 Apr 21;56(4):520-2. Epub 2011 Jan 21.

Department of Respiratory Care, St Francis Medical Center, Cape Girardeau, Missouri, USA.

Partial or total obstruction of an endotracheal tube (ETT) by mucus can cause severe respiratory distress, hypoxemia, or death. Signs of an obstructed ETT include increased ventilation pressure, changes in the ventilator graphics, S(pO(2)) decrease, and cardiovascular changes. We present 3 patients whose ETTs were partially obstructed by mucus. Read More