Purpose: To investigate retinal venous pressure (RVP) as a function of airway pressure (AirP) during the Valsalva maneuver (VM) in human subjects.
Methods: Forty-three healthy volunteers (age, 22.0 (2.3) years) (median and interquartile range) were investigated using the following instruments: dynamic contour tonometer, contact lens dynamometer (CLD), and aneroid manometer. The following measurements were performed in their left eyes: tonometry and dynamometry during VM at different levels of airway pressure (AirP = 0, 10, 20, 30, and 40 mmHg).
Results: The median RVP during spontaneous breathing (AirP = 0) was 19.7 (6.4) (median in mmHg (interquartile range)) and the intraocular pressure (IOP) in mydriasis was 16.3 (3.1) mmHg. Spontaneous pulsation occurred in 58.1% of the subjects. RVP increased nonlinearly. The coefficient of variation of four individual measurements of RVP at each pressure level averaged 8.1 (7.6) %. At different AirP levels of 10, 20, 30, and 40 mmHg, the following RVPs were measured: 29.6 (12.6); 34.2 (12.8); 38.0 (10.5); and 40.3 (11.0), respectively. The rise of RVP (Δ RVP) during VM was significantly higher than that of Δ IOP (p < 0.0001, Wilcoxon test). Δ RVP between 0 and 40 mmHg AirP was 20.6 mmHg and Δ IOP 1.5 mmHg. The steepest slope of the RVP/AirP curve was observed at the first step from 0 to 10 mmHg of AirP (∆ RVP = 9.9 mmHg).
Conclusion: A nonlinear relationship between RVP and AirP was found during VM. Small rises in AirP increase the RVP and affect retinal circulation.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/s00417-020-04796-4 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
CPAP Therapy for OSA and Its Impact on Various Cardiovascular Disorders.
Cardiol Rev
January 2025
Ghulam Muhammad Mahar Medical College, Sukkur, Pakistan.
Obstructive sleep apnea (OSA), a highly prevalent and serious disorder with significant complications, causes considerable daytime and nighttime symptoms as well as long-term consequences and is yet an underdiagnosed and inadequately treated condition. Patients with OSA undergo frequent awakenings during the sleep cycle and find it impossible to get restorative sleep. Individuals are extremely fatigued, sleepy, and irritable throughout the day.
View Article and Find Full Text PDFMulticentre study conducted across centres in the USA, Europe and Australia to assess the safety and effectiveness of a bilateral hypoglossal nerve stimulation system for the treatment of obstructive sleep apnoea in adults: a protocol for a pivotal, multicentre, open-label, single-arm study.
BMJ Open
December 2024
Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
Introduction: Obstructive sleep apnoea (OSA) is characterised by blood oxygen desaturations and sleep disruptions manifesting undesirable consequences. Existing treatments including oral appliances, positive airway pressure (PAP) therapy and surgically altering the anatomy of the pharynx have drawbacks including poor long-term adherence or often involving irreversible, invasive procedures. Bilateral hypoglossal nerve stimulation (HNS) is a new treatment for managing OSA, and this study is intended to determine whether an HNS system is a safe and effective treatment option for adults with OSA.
View Article and Find Full Text PDFComparison of I-gel and Baska mask in elective surgery: a meta-analysis.
BMJ Open
December 2024
Department of Intensive Care, Cangzhou Central Hospital, Cangzhou, China
Objective: The supraglottic airway device is a viable alternative to tracheal intubation for elective surgery. To conduct a comparative analysis of the advantages and disadvantages associated with use of the Baska mask and I-gel across various dimensions.
Design: A comprehensive search was conducted across PubMed, Embase, Cochrane Library, Web of Science, and other relevant databases to identify randomised controlled trials (RCTs) involving patients who used the Baska mask and I-gel.
Active cycle of breathing technique versus oscillating positive expiratory pressure therapy: Effect on lung function in children with primary ciliary dyskinesia; A feasibility study.
Chron Respir Dis
January 2025
Department of Physiotherapy & Rehabilitation, Faculty of Health Professions, Al-Quds University, East Jerusalem, Palestine.
Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder requiring airway clearance techniques for mucus removal. We aimed to evaluate the feasibility and the effect of the active cycle of breathing technique (ACBT) versus oscillating positive expiratory pressure therapy (OPEP) in improving lung function and functional exercise capacity among children with PCD in Palestine. 32 PCD children (6-18 years) were included in a 12-week home-based feasibility study.
View Article and Find Full Text PDFTowards constructing a generalized structural 3D breathing human lung model based on experimental volumes, pressures, and strains.
PLoS Comput Biol
January 2025
Department of Mechanical Engineering, University of California Riverside, Riverside, California, United States of America.
Respiratory diseases represent a significant healthcare burden, as evidenced by the devastating impact of COVID-19. Biophysical models offer the possibility to anticipate system behavior and provide insights into physiological functions, advancements which are comparatively and notably nascent when it comes to pulmonary mechanics research. In this context, an Inverse Finite Element Analysis (IFEA) pipeline is developed to construct the first continuously ventilated three-dimensional structurally representative pulmonary model informed by both organ- and tissue-level breathing experiments from a cadaveric human lung.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!