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• Apnea and HFJV at 300–400 Hz induce minimal surrogate marker movement. • Apnea and HFJV at 300–400 Hz induce hypercapnia. • Tidal volume of 80 ml observed with HFJV at 200 Hz results in effective CO 2 removal. • HFJV at 200 Hz is the best compromise between lung immobilization and gas exchange. • Abdominal motion is highly correlated to diaphragm motion. Respiratory-induced motion introduces uncertainties in the delivery of dose in radiotherapy treatments. Various methods are used clinically, e.g. breath-holding, while there is limited experience with other methods such as apneic oxygenation and high frequency jet ventilation (HFJV). This study aims to compare the latter approaches for lung immobilization and their clinical impact on gas exchange in an animal model. Two radiopaque tumor surrogate markers (TSM) were placed in the central (cTSM) and peripheral (dTSM) regions of the lungs in 9 anesthetized and muscle relaxed pigs undergoing 3 ventilatory interventions (1) HFJV at rates of 200 (JV200), 300 (JV300) and 400 (JV400) min−1; (2) apnea at continuous positive airway pressure (CPAP) levels of 0, 8 and 16 cmH 2 O; (3) conventional mechanical ventilation (CMV) as reference mode. cTSM and dTSM were visualized using fluoroscopy and their coordinates were computed. The ventilatory pattern was registered, and oxygen and carbon dioxide (pCO 2) partial pressures were measured. The highest range of TSM motion, and ventilation was found during CMV, the lowest during apnea. During HFJV the amount of motion varied inversely with increasing frequency. The reduction of TSM motion at JV300, JV400 and all CPAP levels came at the cost of increased pCO 2 , however the relatively low frequency of 200 min−1 for HFJV was the only ventilatory setting that enabled adequate CO 2 removal. In this model , HFJV at 200 min−1 was the best compromise between immobilization and gas exchange for sessions of 10-min duration. [ABSTRACT FROM AUTHOR]

Lung transplantation is a complex but effective treatment of end-stage pulmonary disease. Among the post-operative complications, phrenic nerve injury, and consequent diaphragmatic dysfunction are known to occur but are hitherto poorly described. We aimed to investigate the effect of lung transplantation on diaphragmatic function with a multimodal approach. A total of 30 patients were studied at 4 time points: pre-operatively, at discharge after surgery, and after approximately 6 and subsequently 12 months post surgery. The diaphragmatic function was studied in terms of geometry (assessed by the radius of the diaphragmatic curvature delineated on chest X-ray), weakness (considering changes in forced vital capacity when the patient shifted from upright to supine position), force (maximal pressure during sniff), mobility (excursion of the dome of the diaphragm delineated by ultrasound), contractility (thickening fraction assessed by ultrasound), electrical activity (latency and area of compound muscle action potential during electrical stimulation of phrenic nerve), and kinematics (relative contribution of the abdominal compartment to tidal volume). Despite good clinical recovery (indicated by spirometry and 6 minutes walking test), a reduction of the diaphragmatic function was detected at discharge; it persisted 6 months later to recover fully 1 year after transplantation. Diaphragmatic dysfunction was demonstrated in terms of force, weakness, electrical activity, and kinematics. Our data suggest that the dysfunction was caused by phrenic nerve neurapraxia or moderate axonotmesis, potentially as a consequence of the surgical procedure (i.e., the use of ice and pericardium manipulation). The occurrence of diaphragmatic dysfunction in patients with a good clinical recovery indicates that the evaluation of diaphragmatic function should be included in the post-operative assessment after lung transplantation. [ABSTRACT FROM AUTHOR]

Newborns affected by congenital diaphragmatic hernia (CDH) need cardio-respiratory stabilization before undergoing surgical repair. Open lung strategy is a well-established approach to optimize lung volume in preterm infants with Respiratory Distress Syndrome (RDS), using both High Frequency Oscillatory Ventilation (HFOV) and Conventional Mechanical Ventilation (CMV). We report a case of left CDH with severe lung hypoplasia, managed applying open lung strategy in HFOV (pre-surgery period) and in Assist-Control with Volume Guarantee (post-surgery period), guided by SpO 2 changes, TcPO 2 and TcPCO 2 monitoring. Opto-electronic plethysmography was used to measure end-expiratory chest wall volume changes (ΔEEcw) related to lung volume variations occurring during pressure changes. OEP confirmed the efficacy of using SpO 2 and transcutaneous gas monitoring during this recruitment maneuver. [ABSTRACT FROM AUTHOR]

It is not completely described how aging affect ventilatory kinematics and what are the mechanisms adopted by the elderly population to overcome these structural modifications. Given this, the aim was to evaluate the acute effects of different inspiratory efforts on ventilatory pattern and chest wall compartmental distribution in elderly women. Variables assessed included: tidal volume (Vt), total chest wall volume (Vcw), pulmonary rib cage (Vrcp%), abdominal rib cage (Vrca%) and abdominal compartment (Vab%) relative contributions to tidal volume. These variables were assessed during quiet breathing, maximal inspiratory pressure maneuver (MIP), and moderate inspiratory resistance (MIR; i.e., 40% of MIP). 22 young women (age: 23.9 ± 2.5 years) and 22 elderly women (age: 68.2 ± 5.0 years) participated to this study. It was possible to show that during quiet breathing, Vab% was predominant in elderly ( p < 0.001), in young, however, Vab% was similar to Vrcp% ( p = 0.095). During MIR, Vrcp% was predominant in young ( p < 0.001) and comparable to Vab% in elderly ( p = 0.249). When MIP was imposed, both groups presented a predominance of Vrcp%. In conclusion, there are differences in abdominal kinematics between young and elderly women during different inspiratory efforts. In elderly, during moderate inspiratory resistance, the pattern is beneficial, deep, and slow. Although, during maximal inspiratory resistance, the ventilatory pattern seems to predict imminent muscle fatigue. [ABSTRACT FROM AUTHOR]

Highlights: [•] In SMA motor neurons degenerate and determine muscle wasting and weakness. [•] In SMA II and IIIA, intercostal muscles are weakened and the diaphragm is spared. [•] In SMA II and IIIA, diaphragm leads inspiration with possible thoracic inwarding. [•] In SMA IIIB all inspiratory muscles are preserved. [•] SMA III sub-classification is valid both for motor and respiratory function. [ABSTRACT FROM AUTHOR]

Highlights: [•] We evaluated obese women during quiet breathing. [•] The chest wall volumes and breathing patterns were assessed. [•] Obese women were characterized by lung restriction and higher minute ventilation at rest. [•] Volume variations of the pulmonary rib cage are lower and volume variations of the abdomen are higher in obese women. [•] The kind of obesity, either central or peripheral, does not further influence lung function and thoraco-abdominal pattern. [ABSTRACT FROM AUTHOR]

Abstract: To investigate the effects of posture and gender on thoraco-abdominal motion and breathing pattern, 34 healthy men and women were studied by Opto-Electronic Plethysmography during quiet breathing in five different postures from seated (with and without back support) to supine position. Chest wall kinematics and breathing pattern were significantly influenced by position and gender. The progressively increased inclination of the trunk determined a progressive reduction of rib cage displacement, tidal volume, and minute ventilation and a progressive increase of abdominal contribution to tidal volume. Female subjects were characterized by smaller dimensions of the rib cage compartment and during quiet breathing by lower tidal volume, minute ventilation and abdominal contribution to tidal volume than males. The effect of posture on abdominal kinematics was significant only in women. The presence of a back support in seated position determined differences in breathing pattern. In conclusion, posture and gender have a strong influence on breathing and on chest wall kinematics. [Copyright &y& Elsevier]

Abstract: Breath-by-breath (BbB) oxygen uptake rate was measured at the mouth (MO) and at the alveolar level, at the onset of square wave cycling exercise of moderate intensity in six healthy male subjects. Alveolar BbB values were calculated correcting MO values by (i) estimating (GR); and (ii) measuring (opto-electronic plethysmography, OEP) BbB lung O2 store changes. kinetics was then described by a bi-exponential model. GR yielded larger values of the time constants (τ 2) of the primary phase of kinetics. The mean response times (MRTs) calculated by analysing GR BbB values were larger than (i) those obtained by using MO and OEP at 90W; and (ii) that by using MO at 120W. OEP corrected yielded the highest normalised amplitude of the cardiodynamic phase of the on-response. Correction of BbB for actual BbB changes of lung O2 stores by OEP thus seems more appropriate for the study of the early cardiodynamic phase of kinetics than GR. [Copyright &y& Elsevier]