Expiratory Effort Research Articles

Regarding the high-flow nasal cannula response in the expiratory effort in pediatrics

Regarding the high-flow nasal cannula response in the expiratory effort in pediatrics

Effects of neuromuscular blockers on transpulmonary pressures in moderate to severe acute respiratory distress syndrome.

To investigate whether neuromuscular blocking agents (NMBA) exert beneficial effects in acute respiratory distress syndrome (ARDS) by reason of their action on respiratory mechanics, particularly transpulmonary pressures (P L). A prospective randomised controlled study in patients with moderate to severe ARDS within 48h of the onset of ARDS. All patients were monitored by means of an oesophageal catheter and followed up for 48h. Moderate ARDS patients were randomised into two groups according to whether they were given a 48-h continuous infusion of cisatracurium besylate or not (control group). Severe ARDS patients did not undergo randomisation and all received cisatracurium besylate per protocol. The changes during the 48-h study period in oxygenation and in respiratory mechanics, including inspiratory and expiratory P L and driving pressure, were assessed and compared. Delta P L (∆P L) was defined as inspiratory P L minus expiratory P L. Thirty patients were included, 24 with moderate ARDS and 6 with severe ARDS. NMBA infusion was associated with an improvement in oxygenation in both moderate and severe ARDS, accompanied by a decrease in both plateau pressure and total positive end-expiratory pressure. The mean inspiratory and expiratory P L were higher in the moderate ARDS group receiving NMBA than in the control group. In contrast, there was no change in either driving pressure or ∆P L related to NMBA administration. NMBA could exert beneficial effects in patients with moderate ARDS, at least in part, by limiting expiratory efforts.

The Concave Shape of the Forced Expiratory Flow-Volume Curve in 3 Seconds Is a Practical Surrogate of FEV1/FVC for the Diagnosis of Airway Limitation in Inadequate Spirometry.

Spirometry is important for the differential diagnosis of dyspnea. However, some patients cannot exhale for ≥6 s to achieve the American Thoracic Society/European Respiratory Society criteria. The aim of this study was to demonstrate the reliability of a new parameter that quantifies the degree of concavity in the first 3 s to define airway limitation as a surrogate for the FEV1/FVC. Four hundred spirometry test results were selected through complete random sampling. The new parameter, termed the AUC3/AT3, was calculated as the area under the descending limb of the expiratory flow-volume curve before the end of the first 3 s (AUC3) divided by the area of the triangle before the end of the first 3 s (AT3). The AUC3/AT3 was compared with the FEV1/FVC using Pearson's correlation analysis. The level of agreement between the AUC3/AT3 and the FEV1/FVC in the detection of airway obstruction was analyzed using the kappa statistic. We also compared the diagnostic accuracy of the new index with that of the FEV1/forced expiratory volume in the first 3 s (FEV3). There was a strong correlation (r = 0.88, P < .001) between the AUC3/AT3 and the FEV1/FVC. There was also strong agreement between the AUC3/AT3 and the FEV1/FVC in the detection of obstruction with kappa indices of 0.72 (Global Initiative for Chronic Obstructive Lung Disease [GOLD] criterion) and 0.67 (lower limit of normal criterion), and these values were greater than those obtained for the FEV1/FEV3. The AUC3/AT3 also exhibited acceptable sensitivity, specificity, positive predictive value, and negative predictive value. The diagnostic accuracies of the AUC3/AT3 were 86.3% (GOLD criterion) and 83.8% (lower limit of normal criterion), which were greater than the 76.0 and 74.0% obtained for the FEV1/FEV3, respectively. The AUC3/AT3 can be utilized as a surrogate parameter for the FEV1/FVC when patients cannot complete a 6-s expiratory effort. Additionally, the performance of this index is better than that of the FEV1/FEV3 in the identification of airway limitations.

Angle β of greater than 80° at the start of spirometry may identify high-quality flow volume curves.

The American Thoracic Society (ATS) and European Respiratory Society (ERS) emphasize a satisfactory start in maximal expiratory flow-volume (MEFV) curves and highlight subjective parameters: performance without hesitation and expiration with maximum force. We described a new parameter, angle β for characterization of the start to the MEFV curve. Subjects completed the MEFV curve at least three times and at least two curves met ATS/ERS quality. Subjects were divided into normal, restrictive and obstructive groups according to pulmonary function test results. The tangent line was drawn at the start of the MEFV curve's ascending limb to the x-axis and the angle β between the tangent line and x-axis was obtained. The relationships between tangent of β, pulmonary function parameters (PFPs) and anthropometric data were assessed. The MEFV curves with insufficient explosion at the start were considered as poor-quality MEFV curves. In 998 subjects with high-quality spirometry, although PFP varied in relation to the three aspects: the angle β and its tangent were similar (P > 0.05), the tangent of β did not correlate with PFP or anthropometric measurements (P > 0.05) and the lower limit of normal (LLN) of the angle β was 80° in the group with high-quality spirometry (P < 0.05). Angle β derived from poor-quality MEFV curves was smaller than that from good quality one (P < 0.05). Angle β may function as a parameter to assess the expiratory efforts, which can be used to assess the quality of the MEFV curve start.

Clinical manifestations of acute asthma in children at the Department of Child Health Cipto Mangunkusumo Hospital

Background Acute asthma is an asthma attack or worsening ofasthma manifestation and pulmonary function. Severe asthma at-tack might be prevented by early recognition of the attack and ap-propriate therapy. Clinical manifestations of asthma in children varywidely, so does the assessment of the attack that is often not accu-rately defined by doctors. This leads to delayed and inadequatetreatment of the attack.Objective This study aimed to know the clinical manifestationsof acute asthma in children at the Department of Child Health, Medi-cal School University of Indonesia/Cipto Mangunkusumo Hospi-tal.Methods This was a descriptive, cross sectional study, conductedat the emergency room (ER), the Pediatric Pulmonology Outpa-tient Clinic, and the Pediatric Outpatient Clinic. Subjects were asth-matics who were having attack and aged 2-18 year-old. Data ofage, sex, pulse rate, respiratory rate, duration of attack, expiratory,and inspiratory effort signs were obtained by history and physicalexamination followed by the assessment of attack severity.Results Subjects consisted of 92 children, mostly obtained fromthe ER (40%), with male to female ratio of 1.5:1 and average ageof 5.8 years old. Most of the subjects had mild attack (83%) andduration of attack of less than 24 hours (56%). Most subjects (70%)only had signs of increased expiratory effort, in which all of themhad mild attack. The rest of the subjects showed the combinationof inspiratory and expiratory efforts; 12 patients with mild attack,15 with moderate attack, and 1 with severe attack.Conclusion Patients who only showed expiratory effort usuallyhad mild attack. Patients showing expiratory and inspiratory ef-forts usually had mild or moderate attack. Treatment should betailored to the degree of attack

Respiratory motor training and neuromuscular plasticity in patients with chronic obstructive pulmonary disease: A pilot study

The objective of this study was to examine the feasibility of a full-scale investigation of the neurophysiological mechanisms of COPD-induced respiratory neuromuscular control deficits. Characterization of respiratory single- and multi-muscle activation patterns using surface electromyography (sEMG) were assessed along with functional measures at baseline and following 21±2 (mean±SD) sessions of respiratory motor training (RMT) performed during a one-month period in four patients with GOLD stage II or III COPD.Pre-training, the individuals with COPD showed significantly increased (p<0.05) overall respiratory muscle activity and disorganized multi-muscle activation patterns in association with lowered spirometrical measures and decreased fast- and slow-twitch fiber activity as compared to healthy controls (N=4). Following RMT, functional and respiratory sEMG activation outcomes during quite breathing and forced expiratory efforts were improved suggesting that functional improvements, induced by task-specific RMT, are evidence respiratory neuromuscular networks re-organization.

Maximal expiratory pressure and Valsalva manoeuvre do not produce similar cardiovascular responses in healthy men.

What is the central question of this study? This is the first study to evaluate and describe the cardiovascular responses during maximal expiratory pressure compared with the Valsalva manoeuvre, and whether those responses are similar. What is the main finding and its importance? This study showed that the duration of the manoeuvres appears to be responsible for the different physiological mechanisms involved in the cardiovascular responses to each manoeuvre and that the intensity of expiratory effort was related to the response in maximal expiratory pressure. These results are important to identify the risks to which subjects are exposed when performing these manoeuvres. The main purpose of this study was to compare the cardiovascular responses between the Valsalva manoeuvre (VM) and maximal expiratory pressure (MEP) and to evaluate the effect of age on these responses. Twenty-eight healthy men were evaluated and divided into two groups, younger (n=15, 25±5years) and middle aged (n=13, 50±5years), and they performed the VM and MEP measurement. The VM consisted of an expiratory effort (40mmHg) against a manometer for 15s, and the MEP was performed according to American Thoracic Society guidelines. The cardiovascular responses were analysed at rest, isotime (3s), peak, nadir and recovery, and the cardiovascular variations (Δ) were calculated as peak or isotime minus resting values. For the statistical analysis, we used two-way ANOVA (P<0.05). We observed that MEP and the VM generate similar changes in cardiac output (P>0.05), but MEP presents higher values for mean arterial pressure (MAPPeak , MAPIsotime , ΔMAP and ΔMAPIsotime ) than those observed in the VM (P<0.05). The execution time of the manoeuvres (VM ∼15s and MEP ∼5s) appears to be largely responsible for the activation of different physiological mechanisms involved in the cardiovascular control for each manoeuvre, and the intensity of expiratory effort is related to the higher response of MAP and peripheral vascular resistance (PVRIsotime and ΔPVRIsotime ) during MEP (P<0.05). Moreover, it appears that age affects only the heart rate and PVR responses (P<0.05), which were higher in the young and middle-aged group, respectively. Based on these findings, we can conclude that MEP and the VM do not generate similar cardiovascular responses, except for cardiac output.

A study of peak expiratory flow rate in normal healthy children of Punjab

Background: Peak expiratory flow rate (PEFR) recording is an essential measure in the management and evaluation of asthmatic children. Objective: The present study was undertaken to establish normal reference values for PEFR in normal healthy children of Punjab and to study the influence of height, age, weight and gender on PEFR. Method: -The study was carried out at various schools in the Patiala, Punjab. A total number of 250 children aged between 5-17 yrs were taken. The study included information about the socio demographic characteristics and General Physical Examination was done along with Systemic Examination. PEFR was measured with Mini-Wright Peak Flow Meter. Result: PEFR had highly significant positive co-relation with age , height and weight both in male and female children . PEFR increased with increasing age with highest at the age range of 14-17 yrs (p 0.05), significant(p<0.05) in the age group 10-13 yrs and highly significant (p<0.01) in the age group of 14-17 yrs. These changes may be attributed in males to the better height , weight, and possibly because of more expiratory effort.

Impact of Clinical and Quality of Life Outcomes of Long-Stay ICU Survivors Recovering From Rehabilitation on Caregivers' Burden.

The objective of this work was to evaluate the time course of clinical and health-related quality of life outcomes of long-stay ICU survivors' and caregivers' burden. The study included 23 subjects of mixed diagnosis (66 ± 11 y, body mass index 26.5 ± 5.6 kg/m(2)) with a recent episode of acute respiratory failure needing in-hospital rehabilitation. Subjects and caregivers were evaluated at hospital discharge (T0, n = 23) and 6 months later (T6, n = 16). At T0 and T6, subjects' clinical status (Dependence Nursing Scale), FVC (percent-of-predicted FVC and percent-of-predicted FEV), maximum inspiratory/expiratory pressures, effort tolerance (sit-to-stand, Takahashi test, 6-min walking distance), and disability (Barthel index) were evaluated. EuroQol-5D (EQ-5D), McGill Quality of Life, General Perceived Self-Efficacy Scale, and Hospital Anxiety and Depression Scale (HADS-A/HADS-D) were assessed. Caregivers' burden was measured by the Family Strain Questionnaire short form and Caregiver Needs Assessment. Correlation between subjects' clinical status and caregiver assessments was performed at T0. At T0, subjects showed compromised EQ-5Dindex (0.42 ± 0.28); 69% of caregivers had high Family Strain Questionnaire and moderate Caregiver Needs Assessment scores (30 ± 13). EQ-5Dindex was significantly related to Dependence Nursing Scale score (P < .001), percent-of-predicted FVC (P < .02), effort tolerance (all P < .01), disability (P < .001), and caregiver Family Strain Questionnaire score (P < .02). At T6, subjects significantly improved percent-of-predicted FVC (P < .05), maximum expiratory pressure (P < .01), effort tolerance (all P < .05), disability (P < .02), and EQ-5Dindex (P < .05), whereas caregivers' burden scores were unchanged. However, the percentage of caregivers with strain increased. In prolonged-ICU-stay survivors, EQ-5Dindex at hospital discharge is related to clinical status and caregivers' strain. Subjects' clinical status and EQ-5Dindex improves over time, but caregivers' burden remains high, suggesting the need to monitor/support caregivers.

The Valsalva manoeuvre: physiology and clinical examples.

The Valsalva manoeuvre (VM), a forced expiratory effort against a closed airway, has a wide range of applications in several medical disciplines, including diagnosing heart problems or autonomic nervous system deficiencies. The changes of the intrathoracic and intra-abdominal pressure associated with the manoeuvre result in a complex cardiovascular response with a concomitant action of several regulatory mechanisms. As the main aim of the reflex mechanisms is to control the arterial blood pressure (BP), their action is based primarily on signals from baroreceptors, although they also reflect the activity of pulmonary stretch receptors and, to a lower degree, chemoreceptors, with different mechanisms acting either in synergism or in antagonism depending on the phase of the manoeuvre. A variety of abnormal responses to the VM can be seen in patients with different conditions. Based on the arterial BP and heart rate changes during and after the manoeuvre several dysfunctions can be hence diagnosed or confirmed. The nature of the cardiovascular response to the manoeuvre depends, however, not only on the shape of the cardiovascular system and the autonomic function of the given patient, but also on a number of technical factors related to the execution of the manoeuvre including the duration and level of strain, the body position or breathing pattern. This review of the literature provides acomprehensive analysis of the physiology and pathophysiology of the VM and an overview of its applications. A number of clinical examples of normal and abnormal haemodynamic response to the manoeuvre have been also provided.

Cardiac Autonomic Adjustments During Baroreflex Test in Obese and Non-Obese Preadolescents.

BackgroundRecent studies have shown changes in cardiac autonomic control of obese preadolescents.ObjectiveTo assess the heart rate responses and cardiac autonomic modulation of obese preadolescents during constant expiratory effort.MethodsThis study assessed 10 obese and 10 non-obese preadolescents aged 9 to 12 years. The body mass index of the obese group was between the 95th and 97th percentiles of the CDC National Center for Health Statistics growth charts, while that of the non-obese group, between the 5th and 85th percentiles. Initially, they underwent anthropometric and clinical assessment, and their maximum expiratory pressures were obtained. Then, the preadolescents underwent a constant expiratory effort of 70% of their maximum expiratory pressure for 20 seconds, with heart rate measurement 5 minutes before, during and 5 minutes after it. Heart rate variability (HRV) and heart rate values were analyzed by use of a software.ResultsThe HRV did not differ when compared before and after the constant expiratory effort intra- and intergroup. The heart rate values differed (p < 0.05) during the effort, being the total variation in non-obese preadolescents of 18.5 ± 1.5 bpm, and in obese, of 12.2 ± 1.3 bpm.ConclusionThe cardiac autonomic modulation did not differ between the groups when comparing before and after the constant expiratory effort. However, the obese group showed lower cardiovascular response to baroreceptor stimuli during the effort, suggesting lower autonomic baroreflex sensitivity.

Respiratory muscle fatigue and functional capacity in heart failure: a randomized study

Aim: To compare the effect of inspiratory muscle and expiratory muscle fatigue on the functional capacity in outpatients with systolic heart failure. Method: a randomized, crossover study, controlled, double-blind, focusing on outpatients, from June 2014 to December 2015. Individuals will be allocated to a group that will perform 80% inspiratory and expiratory muscle effort (IME and EME) in terms of maximum airway pressure to induce fatigue, or 0% for the placebo (three sets of 10 repetitions). The order in terms of effort and load will be randomized. Before and after the respiratory muscle effort, capillary lactate testing and a six-minute walk test will be performed. Expected results: Specific training for respiratory muscles can improve the functional capacity and the prognosis of these patients with systolic heart failure .

Kinetics of Respiratory Syncytial Virus (RSV) Memphis Strain 37 (M37) Infection in the Respiratory Tract of Newborn Lambs as an RSV Infection Model for Human Infants.

RationaleRespiratory syncytial virus (RSV) infection in preterm and newborn infants can result in severe bronchiolitis and hospitalization. The lamb lung has several key features conducive to modeling RSV infection in human infants, including susceptibility to human strains of RSV such as the A2, Long, and Memphis Strain 37 (M37). In this study, the kinetics of M37 infection was investigated in newborn lambs in order to better define clinical, viral, physiological, and immunological parameters as well as the pathology and lesions.MethodsNewborn lambs were nebulized with M37 hRSV (6 mL of 1.27 x 107 FFU/mL), monitored daily for clinical responses, and respiratory tissues were collected from groups of lambs at days 1, 3, 4, 6, and 8 post-inoculation for the assessment of viral replication parameters, lesions and also cellular, immunologic and inflammatory responses.ResultsLambs had increased expiratory effort (forced expiration) at days 4, 6, and 8 post-inoculation. Nasal wash lacked RSV titers at day 1, but titers were present at low levels at days 3 (peak), 4, and 8. Viral titers in bronchoalveolar lavage fluid (BALF) reached a plateau at day 3 (4.6 Log10 FFU/mL), which was maintained until day 6 (4.83 Log10 FFU/mL), and were markedly reduced or absent at day 8. Viral RNA levels (detected by RT-qPCR) in BALF were indistinguishable at days 3 (6.22 ± 0.08 Log10 M37 RNA copies/mL; mean ± se) and 4 (6.20 ± 0.16 Log10 M37 RNA copies/mL; mean ± se) and increased slightly on day 6 (7.15 ± 0.2 Log10 M37 RNA copies/mL; mean ± se). Viral antigen in lung tissue as detected by immunohistochemistry was not seen at day 1, was present at days 3 and 4 before reaching a peak by day 6, and was markedly reduced by day 8. Viral antigen was mainly present in airways (bronchi, bronchioles) at day 3 and was increasingly present in alveolar cells at days 4 and 6, with reduction at day 8. Histopathologic lesions such as bronchitis/bronchiolitis, epithelial necrosis and hyperplasia, peribronchial lymphocyte infiltration, and syncytial cells, were consistent with those described previously for lambs and infants.ConclusionThis work demonstrates that M37 hRSV replication in the lower airways of newborn lambs is robust with peak replication on day 3 and sustained until day 6. These findings, along with the similarities of lamb lung to those of infants in terms of alveolar development, airway branching and epithelium, susceptibility to human RSV strains, lesion characteristics (bronchiolitis), lung size, clinical parameters, and immunity, further establish the neonatal lamb as a model with key features that mimic RSV infection in infants.

Evaluation of nasal airway patency by analysis of breathing sounds

Conclusions: A simple non-invasive method, based on acoustic analysis of breathing signals, revealed a potential for objective evaluation of differences between the patency of nasal passageways. Objectives: To examine whether acoustic signals of nasal breathing contain information that can differentiate between obstructed and patent nasal passageways. Method: A technical study aimed to examine measurements of nasal airflow acoustic signals, taken, non-invasively, simultaneously from both external sides of the nostrils. The signals were acquired for several breathing cycles, with different respiratory efforts, before and after application of a nasal decongestant to the (narrower) side that yielded lower amplitudes. Data processing of the expiratory phase yielded the power spectrum density (PSD), which was used to compute the ratio of PSD areas between the signals from both sides of the nose. The study group was composed of 20 healthy volunteers. Results: PSD changes were noted in accordance with the rise in expiratory efforts. The ratio of PSD areas between the two sides of the nasal cavity, calculated for maximal expiratory efforts, correlated well with the side that was treated with nasal decongestant in 18 out of the 20. Changes in the opposite direction were noted in two examinees.

Effect of an anti-reflux medical device in the control of deflation cough: A placebo-controlled comparative study with an antacid drug in chronic coughers

BackgroundDeflation cough (DC), i.e. the cough-like expiratory expulsive efforts evoked by maximal lung emptying, is partially inhibited by prior intake of an antacid. We wished to compare the effects of an anti-reflux medical device (Gastrotuss®) and of a widely used antacid drug (Maalox®) on the number of expiratory thrusts evoked by maximal lung emptying in chronic cough patients. MethodsTwenty consecutive chronic cough outpatients also presenting DC attended the clinic on three separate occasions and were requested to inhale to near total lung capacity and then exhale maximally for at least 6 s. Trained investigators detected aurally the number of cough efforts evoked by maximal lung emptying prior to and 1, 5, 10, 30 e 60 min after administration of either Maalox®, or Gastrotuss® or placebo. The liking of the administered agents was also rated. ResultsIn control conditions, maximal lung emptying was consistently accompanied by the appearance of DC. The number of efforts was unchanged after placebo whereas it was markedly (P < 0.001) reduced 1–10 min following Maalox® and Gastrotuss® administration. The value of liking for Gastrotuss® was greater (P < 0.01) than those of Maalox® and placebo. ConclusionsPre-treatment with anti-reflux agents with a substantially different composition are equally effective in inhibiting DC. The liking of the two compounds used in the present experiments differed considerably and may be important to improve adherence to treatment in patients undergoing long-term therapy for reflux-related symptoms.

The timing of the forced vital capacity.

Based on analysis of more than 2,500 forced vital capacity (FVC) maneuvers, we examined 2 aspects of the standards for spirometry recommended by the 1977 Snowbird Workshop concerning the timing of the FVC maneuver. We compared the forced expiratory volume in one sec (FEV1) when timing was initiated by the back extrapolation method with FEV1 when timing was initiated by flow or volume threshold to determine whether the latter offered a reliable equivalent. Although the mean differences appear to be relatively small, because of variability in initiating expiratory effort, neither alternative is likely to offer a uniformly accurate numeric equivalent to backward extrapolation. We also measured the volume expired before the initiation of the timing as a per cent of FVC to determine whether 10 per cent was a reasonable limit to apply for acceptability of a test. Although 2 SD from the mean of 4.35 per cent were well within this limit, it appears that the technician's judgment of acceptability is sufficient in most cases.

Central administration of nicotine suppresses tracheobronchial cough in anesthetized cats.

We tested the hypothesis that nicotine, which acts peripherally to promote coughing, might inhibit reflex cough at a central site. Nicotine was administered via the vertebral artery [intra-arterial (ia)] to the brain stem circulation and by microinjections into a restricted area of the caudal ventral respiratory column in 33 pentobarbital anesthetized, spontaneously breathing cats. The number of coughs induced by mechanical stimulation of the tracheobronchial airways; amplitudes of the diaphragm, abdominal muscle, and laryngeal muscles EMGs; and several temporal characteristics of cough were analyzed after administration of nicotine and compared with those during control and recovery period. (-)Nicotine (ia) reduced cough number, cough expiratory efforts, blood pressure, and heart rate in a dose-dependent manner. (-)Nicotine did not alter temporal characteristics of the cough motor pattern. Pretreatment with mecamylamine prevented the effect of (-)nicotine on blood pressure and heart rate, but did not block the antitussive action of this drug. (+)Nicotine was less potent than (-)nicotine for inhibition of cough. Microinjections of (-)nicotine into the caudal ventral respiratory column produced similar inhibitory effects on cough as administration of this isomer by the ia route. Mecamylamine microinjected in the region just before nicotine did not significantly reduce the cough suppressant effect of nicotine. Nicotinic acetylcholine receptors significantly modulate functions of brain stem and in particular caudal ventral respiratory column neurons involved in expression of the tracheobronchial cough reflex by a mecamylamine-insensitive mechanism.

Human respiratory syncytial virus memphis 37 causes acute respiratory disease in perinatal lamb lung.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization due to respiratory illness among infants and young children of industrialized countries. There is a lack of understanding of the severe disease mechanisms as well as limited treatment options, none of which are fully satisfactory. This is partly due to lack of a relevant animal model of perinatal RSV infection that mimics moderate to severe disease in infants. We and others have shown mild disease in perinatal lambs with either a bovine or a human A2 strain of RSV. The Memphis 37 clinical strain of human RSV has been used to produce mild to moderate upper respiratory disease in healthy adult volunteers. We hypothesized that the Memphis 37 strain of RSV would infect perinatal lambs and produce clinical disease similar to that in human infants. Perinatal (3- to 5-day-old) lambs were inoculated intranasally with 2 mL/nostril of 1×105 focus-forming units (FFU)/mL (n=2) or 2.1×108 FFU/mL (n=3) of RSV Memphis 37. Clinical signs, gross and histological lesions, and immune and inflammatory responses were assessed. Memphis 37 caused moderate to severe gross and histologic lesions along with increased mRNA expression of macrophage inflammatory protein. Clinically, four of the five infected lambs had a mild to severe increase in expiratory effort. Intranasally administered RSV strain Memphis 37 infects neonatal lambs with gross, histologic, and immune responses similar to those observed in human infants.

Use of air stacking and abdominal compression for cough assistance in people with complete tetraplegia

Cross-sectional. To assess cough using air stacking (AS) to assist inspiratory volume with abdominal compression (AC) during expiration in patients with American Spinal Injury Association Impairment Scale (AIS) A. Large tertiary hospital in Chile. Peak cough flow (PCF) was measured during four different interventions: spontaneous maximal expiratory effort (MEE); MEE while receiving AC (MEE-AC); MEE after AS with a manual resuscitation bag (AS-MEE); and MEE with AS and AC (AS-MEE-AC). Fifteen in-patients with complete tetraplegia (C4-C6) were included. Median age was 33 years (16-56). PCF during the different interventions was PCF for MEE was 183±90 l min(-1); PCF for MEE-AC was 273±119 l min(-1); PCF for AS-MEE was 278±106 l min(-1) and PCF for AS-MEE-AC was 368±129 l min(-1). We observed significant differences in PCF while applying MEE-AC and AS-MEE compared with MEE (P=0.0001). However, the difference in PCF value was greater using the AS-MEE-AC technique (P=0.00001). Patients with spinal cord injury (SCI) presented an ineffective cough that constitutes a risk factor for developing respiratory complications. The application of combined techniques (AS-MEE-AC) can reach near normal PCF values. This is a low-cost, simple and easily applied intervention that could be introduced to all patients with tetraplegia.

Proposal intensity adequacy of expiratory effort and heart rate behavior during the valsalva maneuver in preadolescents.

Background When performing the Valsalva maneuver (VM), adults and preadolescents produce the same expiratory resistance values. Objective To analyze heart rate (HR) in preadolescents performing VM, and propose a new method for selecting expiratory resistance. Method The maximal expiratory pressure (MEP) was measured in 45 sedentary children aged 9-12 years who subsequently performed VM for 20 s using an expiratory pressure of 60%, 70%, or 80% of MEP. HR was measured before, during, and after VM. These procedures were repeated 30 days later, and the data collected in the sessions (E1, E2) were analyzed and compared in periods before, during (0-10 and 10-20 s), and after VM using nonparametric tests. Results All 45 participants adequately performed VM in E1 and E2 at 60% of MEP. However, only 38 (84.4%) and 25 (55.5%) of the participants performed the maneuver at 70% and 80% of MEP, respectively. The HR delta measured during 0-10 s and 10-20 s significantly increased as the expiratory effort increased, indicating an effective cardiac autonomic response during VM. However, our findings suggest the VM should not be performed at these intensities. Conclusion HR increased with all effort intensities tested during VM. However, 60% of MEP was the only level of expiratory resistance that all participants could use to perform VM. Therefore, 60% of MEP may be the optimal expiratory resistance that should be used in clinical practice.