Effect of the measurement of the work of breathing on the respiratory outcome of preterms

Regional distribution of diaphragmatic blood flow (Q; 15-microns-diam radionuclide-labeled microspheres) was studied in normal (n = 7) and laryngeal hemiplegic (LH; n = 7) ponies to determine whether the added stress of inspiratory resistive breathing during maximal exercise may cause 1) redistribution of diaphragmatic Q and 2) crural diaphragmatic Q to exceed that in maximally exercising normal ponies. LH-induced augmentation of already high exertional work of breathing resulted in diminished locomotor exercise capacity so that maximal exercise in LH ponies occurred at 25 km/h compared with 32 km/h for normal ponies. The costal and crural regions received similar Q in both groups at rest. However, exercise-induced increments in perfusion were significantly greater in the costal region of the diaphragm. At 25 km/h, costal diaphragmatic perfusion was 154 and 143% of the crural diaphragmatic Q in normal and LH ponies. At 32 km/h, Q in costal diaphragm of normal ponies was 136% of that in the crural region. Costal and crural diaphragmatic Q in LH ponies exercised at 25 km/h exceeded that for normal ponies but was similar to the latter during exercise at 32 km/h. Perfusion pressure for the three conditions was also similar. It is concluded that diaphragmatic perfusion heterogeneity in exercising ponies was preserved during the added stress of inspiratory resistive breathing. It was also demonstrated that vascular resistance in the crural and costal regions of the diaphragm in maximally exercised LH ponies remained similar to that in maximally exercising normal ponies.

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Respiratory muscle function in the newborn: a narrative review

Pediatric Research ◽

10.1038/s41390-021-01529-z ◽

2021 ◽

Author(s):

Theodore Dassios ◽

Aggeliki Vervenioti ◽

Gabriel Dimitriou

Keyword(s):

Congenital Anomalies ◽

Muscle Function ◽

Respiratory Muscle ◽

Work Of Breathing ◽

Respiratory Muscles ◽

Current Evidence ◽

Muscle Fibres ◽

List Type ◽

Respiratory Muscle Function ◽

Neurally Adjusted Ventilator Assist

Abstract Our aim was to summarise the current evidence and methods used to assess respiratory muscle function in the newborn, focusing on current and future potential clinical applications. The respiratory muscles undertake the work of breathing and consist mainly of the diaphragm, which in the newborn is prone to dysfunction due to lower muscle mass, flattened shape and decreased content of fatigue-resistant muscle fibres. Premature infants are prone to diaphragmatic dysfunction due to limited reserves and limited capacity to generate force and avoid fatigue. Methods to assess the respiratory muscles in the newborn include electromyography, maximal respiratory pressures, assessment for thoraco-abdominal asynchrony and composite indices, such as the pressure–time product and the tension time index. Recently, there has been significant interest and a growing body of research in assessing respiratory muscle function using bedside ultrasonography. Neurally adjusted ventilator assist is a novel ventilation mode, where the level of the respiratory support is determined by the diaphragmatic electrical activity. Prolonged mechanical ventilation, hypercapnia and hypoxia, congenital anomalies and systemic or respiratory infection can negatively impact respiratory muscle function in the newborn, while caffeine and synchronised or volume-targeted ventilation have a positive effect on respiratory muscle function compared to conventional, non-triggered or pressure-limited ventilation, respectively. Impact Respiratory muscle function is impaired in prematurely born neonates and infants with congenital anomalies, such as congenital diaphragmatic hernia. Respiratory muscle function is negatively affected by prolonged ventilation and infection and positively affected by caffeine and synchronised compared to non-synchronised ventilation modes. Point-of-care diaphragmatic ultrasound and neurally adjusted ventilator assist are recent diagnostic and therapeutic technological developments with significant clinical applicability.

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Plasma Creatinine Level Does Not Predict Respiratory Function in Amyotrophic Lateral Sclerosis

Journal of Neuromuscular Diseases ◽

10.3233/jnd-200583 ◽

2021 ◽

pp. 1-5

Author(s):

João Morgadinho ◽

Ana Catarina Pronto-Laborinho ◽

Vasco A. Conceição ◽

Marta Gromicho ◽

Susana Pinto ◽

...

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Creatinine Level ◽

Cox Regression ◽

Functional Decline ◽

Plasma Creatinine ◽

Plasma Creatinine Level ◽

Decline Rate ◽

Respiratory Outcome ◽

Als Patients ◽

Lateral Sclerosis

In amyotrophic lateral sclerosis (ALS) lower plasma creatinine level has been associated with shorter survival and faster functional decline. It has not been clear if creatinine is associated with respiratory outcome. We analyzed retrospectively a population of unselected ALS patients. Multiple-regression and Cox-regression analyses were performed. We included 233 patients, mean age 62.8, mean disease duration of 18.6 months. At baseline, creatinine was significantly associated with ALSFRS-R, but not with its decline rate. No predictive value was disclosed for FVC, or their decline rate, or with survival. We did not confirm that creatinine is a marker of respiratory outcome.

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Thoracic weighting of restrained subjects during exhaustion recovery causes loss of lung reserve volume in a model of police arrest

Scientific Reports ◽

10.1038/s41598-021-94157-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mark Campbell ◽

Roslyn Dakin ◽

Symon Stowe ◽

Kira Burton ◽

Brianna Raven ◽

...

Keyword(s):

Electrical Impedance ◽

Human Subjects ◽

Work Of Breathing ◽

High Sensitivity ◽

Abdominal Muscle ◽

Combined Effects ◽

Impedance Tomography ◽

Head Restraint ◽

Inspiratory Muscles ◽

Life Threatening

AbstractRestraint asphyxia has been proposed as a mechanism for some arrest-related deaths that occur during or shortly after a suspect is taken into custody. Our analysis of the literature found that prone positioning, weight applied to the back, recovery after simulated pursuit, and restraint position have led to restrictive, but non life-threatening respiratory changes when tested in subsets. However, the combined effects of all four parameters have not been tested together in a single study. We hypothesized that a complete protocol with high-sensitivity instrumentation could improve our understanding of breathing physiology during weighted restraint. We designed an electrical impedance tomography (EIT)-based protocol for this purpose and measured the 3D distribution of ventilation within the thorax. Here, we present the results from a study on 17 human subjects that revealed FRC declines during weighted restrained recovery from exercise for subjects in the restraint postures, but not the control posture. These prolonged FRC declines were consistent with abdominal muscle recruitment to assist the inspiratory muscles, suggesting that subjects in restraint postures have increased work of breathing compared to controls. Upon removal of the weighted load, lung reserve volumes gradually increased for the hands-behind-the-head restraint posture but continued to decrease for subjects in the hands-behind-the-back restraint posture. We discuss the possible role this increased work of breathing may play in restraint asphyxia.

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Short-term effects of synchronized vs. non-synchronized NIPPV in preterm infants: study protocol for an unmasked randomized crossover trial

Trials ◽

10.1186/s13063-021-05351-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Francesco Cresi ◽

Federica Chiale ◽

Elena Maggiora ◽

Silvia Maria Borgione ◽

Mattia Ferroglio ◽

...

Keyword(s):

Preterm Infants ◽

Work Of Breathing ◽

Respiratory Rhythm ◽

Assisted Ventilation ◽

Positive Pressure ◽

Invasive Ventilation ◽

Short Term ◽

Non Invasive ◽

Non Invasive Ventilation ◽

Short Term Effects

Abstract Background Non-invasive ventilation (NIV) has been recommended as the best respiratory support for preterm infants with respiratory distress syndrome (RDS). However, the best NIV technique to be used as first intention in RDS management has not yet been established. Nasal intermittent positive pressure ventilation (NIPPV) may be synchronized (SNIPPV) or non-synchronized to the infant’s breathing efforts. The aim of the study is to evaluate the short-term effects of SNIPPV vs. NIPPV on the cardiorespiratory events, trying to identify the best ventilation modality for preterm infants at their first approach to NIV ventilation support. Methods An unmasked randomized crossover study with three treatment phases was designed. All newborn infants < 32 weeks of gestational age with RDS needing NIV ventilation as first intention or after extubation will be consecutively enrolled in the study and randomized to the NIPPV or SNIPPV arm. After stabilization, enrolled patients will be alternatively ventilated with two different techniques for two time frames of 4 h each. NIPPV and SNIPPV will be administered with the same ventilator and the same interface, maintaining continuous assisted ventilation without patient discomfort. During the whole duration of the study, the patient’s cardiorespiratory data and data from the ventilator will be simultaneously recorded using a polygraph connected to a computer. The primary outcome is the frequency of episodes of oxygen desaturation. Secondary outcomes are the number of the cardiorespiratory events, FiO2 necessity, newborn pain score evaluation, synchronization index, and thoracoabdominal asynchrony. The calculated sample size was of 30 patients. Discussion It is known that NIPPV produces a percentage of ineffective acts due to asynchronies between the ventilator and the infant’s breaths. On the other hand, an ineffective synchronization could increase work of breathing. Our hypothesis is that an efficient synchronization could reduce the respiratory work and increase the volume per minute exchanged without interfering with the natural respiratory rhythm of the patient with RDS. The results of this study will allow us to evaluate the effectiveness of the synchronization, demonstrating whether SNIPPV is the most effective non-invasive ventilation mode in preterm infants with RDS at their first approach to NIV ventilation. Trial registration ClinicalTrials.gov NCT03289936. Registered on September 21, 2017.

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