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Abstract Duchenne muscular dystrophy (DMD) is a fatal genetic neuromuscular disease. Lack of dystrophin in skeletal muscles leads to intrinsic weakness, injury, subsequent degeneration and fibrosis, decreasing contractile function. Dystropathology eventually presents in all inspiratory and expiratory muscles of breathing, severely curtailing their critical function. In people with DMD, premature death is caused by respiratory or cardiac failure. There is an urgent need to develop therapies that improve quality of life and extend life expectancy in DMD. Surprisingly, there is a dearth of information on respiratory control in animal models of DMD, and respiratory outcome measures are often limited or absent in clinical trials. Characterization of respiratory performance in murine and canine models has revealed extensive remodelling of the diaphragm, the major muscle of inspiration. However, significant compensation by extradiaphragmatic muscles of breathing is evident in early disease, contributing to preservation of peak respiratory system performance. Loss of compensation afforded by accessory muscles in advanced disease is ultimately associated with compromised respiratory performance. A new and potentially more translatable murine model of DMD, the D2.mdx mouse, has recently been developed. Respiratory performance in D2.mdx mice is yet to be characterized fully. However, based on histopathological features, D2.mdx mice might serve as useful preclinical models, facilitating the testing of new therapeutics that rescue respiratory function. This review summarizes the pathophysiological mechanisms associated with DMD both in humans and in animal models, with a focus on breathing. We consider the translational value of each model to human DMD and highlight the urgent need for comprehensive characterization of breathing in representative preclinical models to better inform human trials.

Abstract Background The endotracheal cuff pressure depends on the airway pressure during positive-pressure ventilation. A high endotracheal cuff pressure may be related to intraoperative coughing, which can be detrimental during neurosurgery. We investigated the incidence of intraoperative coughing and its association with peak inspiratory pressure (PIP) during neurosurgery under general anesthesia without neuromuscular blockade. Methods This retrospective study divided 1656 neurosurgical patients who underwent total intravenous anesthesia without additional neuromuscular blockade after tracheal intubation into high (PIP > 21.6 cmH2O, n = 318) and low (PIP ≤ 21.6 cmH2O, n = 1338) PIP groups. After propensity score matching, 206 patients were selected in each group. Demographic, preoperative, surgical, and anesthetic data were collected retrospectively from electronic medical records and continuous ventilator, infusion pump, and bispectral index data from a data registry. Results Intraoperative coughing occurred in 30 (1.8%) patients, including 9 (0.5%) during the main surgical procedure. Intraoperative coughing was more frequent in the high PIP group than in the low PIP group before (14/318 [4.4%] vs. 16/1338 [1.2%], P

Background: Chest physiotherapy (CPT) and positioning of neonates has been used in many developed countries around the world to improve airway clearance and avoid lung complications, but the combined effect of both techniques is less documented. The objective of the study was to compare the effectiveness of chest physiotherapy in prone position versus conventional chest physiotherapy in ventilated neonates on respiratory outcomes. Methods: The study design was randomized controlled pilot study. Participants: 12 ventilated neonates fitting in Inclusion Criteria. They were randomly divided into two groups (n=6 in each group) using simple random sampling i.e. Experimental group (4female and 2male) (Chest Physiotherapy and Prone Positioning) and the Control group (3 females and 3males) (Conventional Chest Physiotherapy). Primary outcome measures were SpO2 saturation, Partial Pressure of Arterial Oxygen (PaO2) & Peak Inspiratory Pressure (P.I.P.). Outcomes were recorded Pre & Post of every 120 minutes session of Intervention twice daily with a gap of 6 hours for consecutive three days for the experimental group while for the control group, parameters were measured at the same time of the day. Result: Total 10 participants completed the study protocol. On comparison of three parameters in two groups using the unpaired t-test, we found that there was a significant difference (p< 0.05) in SpO2 and PaO2 in both groups but no difference ( p >0.05) in P.I.P. levels. Conclusion: Chest physiotherapy in the prone position for ventilated neonate concluded with a higher oxygen saturation (SpO2) and partial pressure of oxygen in the arterial blood (PaO2) when compared to conventional chest physiotherapy.

BackgroundRespiratory dynamics may be monitored and evaluated indirectly by measuring the peak inspiratory pressure and plateau pressure. In this study, the respiratory dynamics of patients undergoing spinal surgery using a Jackson surgical table were observed with a device after converting their position from supine to prone. The effects of the dynamic compliance and airway resistance were observed from the changes in peak inspiratory pressure and plateau.MethodsTwenty five patients were selected as subjects scheduled to undergo lumbar spine surgery. After intubation, the patients were ventilated mechanically with a tidal volume of 10 ml/kg and a respiration rate of 10/min. Anesthesia was maintained with sevoflurane 1.5%, nitrous oxide 2 L/min and oxygen 2 L/min. The peak inspiratory pressure, plateau pressure, resistance, compliance, arterial oxygen tension, carbon dioxide tension, heart rate and arterial blood pressure were measured at 10 minutes after the induction of anesthesia. These parameters were measured again 10 minutes after placing the patient in the prone position.ResultsThe prone position did not significantly affect the arterial oxygen tension, carbon dioxide tension, blood pressure and heart rate, but significantly increased the peak inspiratory pressure and resistance and decreased the dynamic compliance.ConclusionsThe peak inspiratory pressure was increased using a Jackson surgical table to minimize the abdominal pressure when converting from the supine to prone position. This might be due to a decrease in lung and chest compliance as well as an increase in airway resistance.