scholarly journals Application of continuous positive airway pressure for thoracic respiratory motion management: an assessment in a magnetic resonance imaging-guided radiotherapy environment.

2022 ◽  
pp. 100889
Author(s):  
Evan Liang ◽  
Jennifer L. Dolan ◽  
Eric D. Morris ◽  
Jonathan Vono ◽  
Luisa F. Bazan ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Continuous Positive Airway Pressure ◽  
Magnetic Resonance ◽  
Airway Pressure ◽  
Respiratory Motion ◽  
Positive Airway Pressure ◽  
Resonance Imaging ◽  
Motion Management

Effect of Propofol Anesthesia and Continuous Positive Airway Pressure on Upper Airway Size and Configuration in Infants

2006 ◽  
Vol 105 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Mark W. Crawford ◽  
Denise Rohan ◽  
Christopher K. Macgowan ◽  
Shi-Joon Yoo ◽  
Bruce A. Macpherson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Continuous Positive Airway Pressure ◽  
Magnetic Resonance ◽  
Infusion Rate ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Upper Airway ◽  
Transverse Dimension ◽  
Resonance Imaging ◽  
Airway Caliber

Background Infants are prone to obstruction of the upper airway during general anesthesia. Continuous positive airway pressure (CPAP) is often used to prevent or treat anesthesia-induced airway obstruction. The authors studied the interaction of propofol anesthesia and CPAP on airway caliber in infants using magnetic resonance imaging. Methods Nine infants undergoing elective magnetic resonance imaging of the brain were studied. Head position was standardized. Spin echo magnetic resonance images of the airway were acquired at the level of the soft palate, base of the tongue, and tip of the epiglottis. Four sets of images were acquired in sequence: (1) during light propofol anesthesia at an infusion rate of 80 microg . kg(-1) . min(-1), (2) after increasing the depth of propofol anesthesia by administering a bolus dose (2.0 mg/kg) and increasing the infusion rate to 240 microg . kg(-1) . min(-1), (3) during continued infusion of 240 microg . kg(-1). min propofol and application of 10 cm H2O CPAP, and (4) after removal of CPAP and continued infusion of 240 microg . kg(-1). min propofol. Results Increasing depth of propofol anesthesia decreased airway caliber at each anatomical level, predominantly due to anteroposterior narrowing. Application of CPAP completely reversed the propofol-induced decrease in airway caliber, primarily by increasing the transverse dimension. Conclusions Airway narrowing with increasing depth of propofol anesthesia results predominantly from a reduction in anteroposterior dimension, whereas CPAP acts primarily to increase the transverse dimension. Although airway caliber during deep propofol anesthesia and application of CPAP was similar to that during light propofol anesthesia, there were significant configurational differences.

scholarly journals An Adverse Effect of Positive Airway Pressure on the Upper Airway Documented With Magnetic Resonance Imaging

2013 ◽  
Vol 139 (6) ◽  
pp. 636 ◽  
Author(s):  
Robert J. Fleck ◽  
Mohamed Mahmoud ◽  
Keith McConnell ◽  
Sally R. Shott ◽  
Ephraim Gutmark ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Adverse Effect ◽  
Magnetic Resonance ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Upper Airway ◽  
Resonance Imaging

Effects of Recruitment Maneuver on Atelectasis in Anesthetized Children

2003 ◽  
Vol 98 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Gerardo Tusman ◽  
Stephan H. Böhm ◽  
Alejandro Tempra ◽  
Fernando Melkun ◽  
Eduardo García ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Recruitment Maneuver ◽  
Left Lung ◽  
Alveolar Recruitment ◽  
Recruitment Strategy ◽  
Resonance Imaging ◽  
The Right

Background General anesthesia is known to promote atelectasis formation. High inspiratory pressures are required to reexpand healthy but collapsed alveoli. However, in the absence of positive end-expiratory pressure (PEEP), reexpanded alveoli collapse again. Using magnetic resonance imaging, the impact of an alveolar recruitment strategy on the amount and distribution of atelectasis was tested. Methods The authors prospectively randomized 24 children who met American Society of Anesthesiologists physical status I or II criteria, were aged 6 months-6 yr, and were undergoing cranial magnetic resonance imaging into three groups. After anesthesia induction, in the alveolar recruitment strategy (ARS) group, an alveolar recruitment maneuver was performed by manually ventilating the lungs with a peak airway pressure of 40 cm H2O and a PEEP of 15 cm H2O for 10 breaths. PEEP was then reduced to and kept at 5 cm H2O. The continuous positive airway pressure (CPAP) group received 5 cm H2O of continuous positive airway pressure without recruitment. The zero end-expiratory pressure (ZEEP) group received neither PEEP nor the recruitment maneuver. All patients breathed spontaneously during the procedure. After cranial magnetic resonance imaging, thoracic magnetic resonance imaging was performed. Results The atelectatic volume (median, first and third standard quartiles) detected in the ZEEP group was 1.25 (0.75-4.56) cm3 in the right lung and 4.25 (3.2-13.9) cm3 in the left lung. The CPAP group had 9.5 (3.1-23.7) cm3 of collapsed lung tissue in the right lung and 8.8 (5.3-28.5) cm3 in the left lung. Only one patient in the ARS group presented an atelectasis of less than 2 cm3. An uneven distribution of the atelectasis was observed within each lung and between the right and left lungs, with a clear predominance of the left basal paradiaphragmatic regions. Conclusion Frequency of atelectasis was much less following the alveolar recruitment strategy, compared with children who did not have the maneuver performed. The mere application of 5 cm H2O of CPAP without a prior recruitment did not show the same treatment effect and showed no difference compared to the control group without PEEP.

Structural Changes Following Velopharyngeal Resistance Training (Continuous Positive Airway Pressure Therapy)

2018 ◽  
Vol 55 (9) ◽  
pp. 1321-1328
Author(s):  
Youkyung Bae ◽  
Gwenlyn Pfeil
Keyword(s):  
Magnetic Resonance Imaging ◽  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Structural Changes ◽  
Positive Airway Pressure ◽  
Cpap Therapy ◽  
Resonance Imaging ◽  
Pressure Therapy ◽  
Levator Veli Palatini ◽  
Magnetic Resonance Imaging Mri

Objective: To evaluate the feasibility/effectiveness of using magnetic resonance imaging (MRI) to document velopharyngeal (VP) structural changes induced by continuous positive airway pressure (CPAP) therapy. Outcome Measures: Changes in velar length and thickness, levator veli palatini (LVP) length and thickness, velar volume, and intravelar muscular proportion along the course of CPAP therapy participation (Pre-CPAP, Post-CPAP, and withdrawal). Results: Velar and LVP lengths remained nearly the same, with the median changes (Δ) less than 0.6%, across repeated conditions. Although varying in magnitudes of change, median velar volume (Δ4%), velar thickness (Δ20%), LVP thickness (Δ17%), and intravelar muscular proportion (Δ10%) illustrated a consistent pattern of increases following the 8-week CPAP therapy. These VP structural measurements slightly decreased but remained above the pretraining condition after 8-week detraining. Conclusions: This report successfully demonstrated that MRI is a viable tool to document CPAP therapy–induced VP structural changes while providing preliminary empirical data.

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