Rib Cage Compression Research Articles

Chest physiotherapy techniques administered by certified specialists to hospitalized patients with COVID-19 in Brazil: A look towards future practice

BackgroundChest physiotherapy for hospitalized patients with COVID-19 has been poorly reported. Although recommendations were published to guide physiotherapists, practice might have differed depending on education and training. ObjectiveTo analyze the differences in chest physiotherapy applied for hospitalized patients with COVID-19 between certified specialists and non-certified specialists. MethodsAn online questionnaire survey was developed for physiotherapists involved in the management of hospitalized patients with COVID-19. The questionnaire inquired about professional information and characteristics of physiotherapy practice. ResultsThere were 485 respondents, yielding a completion rate of 76%. Of these, 61 were certified specialists and 424 non-certified specialists. The certified specialists were older, had more years of professional experience, were more qualified, and had better job conditions. For mechanically ventilated patients, the certified specialists used the ventilator hyperinflation maneuver more frequently (50.4% vs 35.1%, p = 0.005), and the hard/brief expiratory rib cage compression (ERCC) (26.9% vs 48.3%, p = 0.016), soft/long ERCC (25.2% vs 39.1%, p = 0.047), and manual chest compression-decompression (MCCD) maneuver (22.4% vs 35.6%, p = 0.001) less often. For spontaneously breathing patients, the certified specialists used the active cycle of breathing technique (30.8% vs 67.1%, p<0.001), autogenic drainage (7.7% vs 20.7%, p = 0.017), and MCCD maneuver (23.1% vs 41.4%, p = 0.018) less frequently. ConclusionsCertified specialists with higher levels of expertise seem to prefer the use of chest physiotherapy techniques that are applied with the mechanical ventilator over manual techniques. Furthermore, they use techniques that could potentially increase the work of breathing less frequently, mitigating the risk of exacerbating respiratory conditions in patients with COVID-19.

Physiotherapy practice for hospitalized patients with COVID-19.

ABSTRACTObjective:To identify the indications for physiotherapy and to evaluate physiotherapy practices in patients with COVID-19 admitted to the ICU (on mechanical ventilation) or to the ward (spontaneously breathing). Methods:An online, 50-item survey was completed by physiotherapists who had been treating hospitalized patients with COVID-19 in Brazil. Results:Of the 644 physiotherapists who initiated the survey, 488 (76%) completed it. The main reasons for indications for physiotherapy in both settings reported as “very frequently” and “frequently” both in the ICU and the ward by most respondents were oxygenation improvement (> 95%) and prevention of general complications (> 83%). Physical deconditioning was considered an infrequent indication. When compared with mobilization strategies, the use of respiratory interventions showed great variability in both work settings, and techniques considered effective were underutilized. The most frequently used respiratory techniques in the ICU were positioning (86%), alveolar recruitment (73%), and hard/brief expiratory rib cage compression (46%), whereas those in the ward were active prone positioning (90%), breathing exercises (88%), and directed/assisted cough (75%). The mobilization interventions reported by more than 75% of the respondents were sitting on the edge of the bed, active and resistive range of motion exercises, standing, ambulation, and stepping in place. Conclusions:The least common reason for indications for physiotherapy was avoidance of deconditioning, whereas oxygenation improvement was the most frequent one. Great variability in respiratory interventions was observed when compared with mobilization therapies, and there is a clear need to standardize respiratory physiotherapy treatment for hospitalized patients with COVID-19.

Effect of positioning and expiratory rib-cage compression on atelectasis in a patient who required prolonged mechanical ventilation: a case report

BackgroundPulmonary complications can be caused by intraoperative mechanical ventilation. In particular, prolonged mechanical ventilation is associated with a high mortality rate, a risk of pulmonary complications, prolonged hospitalization, and an unfavorable discharge destination. Pre- and postoperative rehabilitation are important for the resolution of pulmonary complications in acute cases. However, there has been a lack of studies on interventions for pulmonary rehabilitation of patients with chronic pulmonary complications caused by prolonged mechanical ventilation. Accordingly, we describe the effect of pulmonary rehabilitation in such a patient.Case presentationWe examined a 63-year-old Japanese woman with hypoxic–ischemic encephalopathy after subarachnoid hemorrhage who required prolonged mechanical ventilation. Radiographic and computed tomographic images revealed atelectasis of the right upper lobe. In addition, this atelectasis reduced the tidal volume, minute volume, and oxygen saturation and caused an absence of breath sounds in the right upper lobe during auscultation. We aimed to ameliorate the patient’s atelectasis and improve her ventilation parameters by using positioning and expiratory rib-cage compression after endotracheal suctioning. Specifically, the patient was seated in Fowler’s position, and mild pressure was applied to the upper thorax during expiration, improving her inspiratory volume. Immediately, breath sounds were audible in the right upper lobe. Furthermore, resolution of the patient’s atelectasis was confirmed with chest radiography performed on the same day. In addition, her ventilation parameters (tidal volume, minute volume, and oxygen saturation) improved.ConclusionsOur results indicate that physical therapists should consider application of specific positioning and expiratory rib-cage compression in patients who exhibit atelectasis because of prolonged mechanical ventilation.

A deep look into the rib cage compression technique in mechanically ventilated patients: a narrative review

Defective management of secretions is one of the most frequent complications in invasive mechanically ventilated patients. Clearance of secretions through chest physiotherapy is a critical aspect of the treatment of these patients. Manual rib cage compression is one of the most practiced chest physiotherapy techniques in ventilated patients; however, its impact on clinical outcomes remains controversial due to methodological issues and poor understanding of its action. In this review, we present a detailed analysis of the physical principles involved in rib cage compression technique performance, as well as the physiological effects observed in experimental and clinical studies, which show that the use of brief and vigorous rib cage compression, based on increased expiratory flows (expiratory-inspiratory airflow difference of > 33L/minute), can improve mucus movement toward the glottis. On the other hand, the use of soft and gradual rib cage compression throughout the whole expiratory phase does not impact the expiratory flows, resulting in ineffective or undesired effects in some cases. More physiological studies are needed to understand the principles of the rib cage compression technique in ventilated humans. However, according to the evidence, rib cage compression has more potential benefits than risks, so its implementation should be promoted.

A deep look into the rib cage compression technique in mechanically ventilated patients: a narrative review.

Defective management of secretions is one of the most frequent complications in invasive mechanically ventilated patients. Clearance of secretions through chest physiotherapy is a critical aspect of the treatment of these patients. Manual rib cage compression is one of the most practiced chest physiotherapy techniques in ventilated patients; however, its impact on clinical outcomes remains controversial due to methodological issues and poor understanding of its action. In this review, we present a detailed analysis of the physical principles involved in rib cage compression technique performance, as well as the physiological effects observed in experimental and clinical studies, which show that the use of brief and vigorous rib cage compression, based on increased expiratory flows (expiratory-inspiratory airflow difference of > 33L/minute), can improve mucus movement toward the glottis. On the other hand, the use of soft and gradual rib cage compression throughout the whole expiratory phase does not impact the expiratory flows, resulting in ineffective or undesired effects in some cases. More physiological studies are needed to understand the principles of the rib cage compression technique in ventilated humans. However, according to the evidence, rib cage compression has more potential benefits than risks, so its implementation should be promoted.

A deep look into the rib cage compression technique in mechanically ventilated patients: a narrative review

A deep look into the rib cage compression technique in mechanically ventilated patients: a narrative review

Effects of manual hyperinflation with rib cage compression and endotracheal suctioning on arterial blood gas parameters in mechanically ventilated patients at a university hospital, Egypt

BackgroundManual hyperinflation and expiratory rib cage compression are methods of chest physiotherapy. They are commonly applied but their value and their early utilization managing mechanically ventilated remain questionable. The purpose of the study was to investigate the effects of manual hyperinflation with rib cage compression and endotracheal suctioning on arterial blood gas parameters in mechanically ventilated patients.ResultsSeventy mechanically ventilated patients at a teaching hospital in Egypt were assigned to the clinical trial study. The age of more than half of the studied samples ranged between 60 and 69 years with a mean age of 53.64 ± 16.44 years. Initially, the ABG parameters were assessed. Then, the patients were exposed to manual hyperinflation for 5 min and 20 min external expiratory chest compression followed by endotracheal suctioning. Later, ABG parameters were assessed again and compared to the initial one. The findings revealed significant differences in ABG parameters before and after completion of MHI and ERCC and ETT suctioning in relation to PaO2 (t = 3.892) and SaO2 (t= 5.904). Also, it showed significant improvement in PaO2 and SaO2 after the completion of interventions, while no significant differences were found in other ABG parameters. This study was registered retrospectively with an ISRCTN number 39983 on 5/6/2021.ConclusionApplying manual hyperinflation with rib cage compression and endotracheal suctioning improved mainly the arterial oxygenation parameters in mechanically ventilated patients despite no significant changes observed in other ABG parameters.

Effects of Mechanical Insufflation-Exsufflation on Sputum Volume in Mechanically Ventilated Critically Ill Subjects.

Mechanical insufflation-exsufflation (MI-E) is a noninvasive technique performed to simulate cough and remove sputum from proximal airways. To date, the effects of MI-E on critically ill patients on invasive mechanical ventilation are not fully elucidated. In this randomized crossover trial, we evaluated the efficacy and safety of MI-E combined to expiratory rib cage compressions (ERCC). Twenty-six consecutive subjects who were sedated, intubated, and on mechanical ventilation > 48 h were randomized to perform 2 sessions of ERCC with or without additional MI-E before tracheal suctioning in a 24-h period. The primary outcome was sputum volume following each procedure. Secondary end points included effects on respiratory mechanics, hemodynamics, and safety. In comparison to ERCC alone, median (interquartile range) sputum volume cleared was significantly higher during ERCC+MI-E (0.42 [0-1.39] mL vs 2.29 [1-4.67] mL, P < .001). The mean ± SD respiratory compliance improved in both groups immediately after the treatment, with the greater improvement in the ERCC+MI-E group (54.7 ± 24.1 mL/cm H2O vs 73.7 ± 35.8mL/cm H2O, P < .001). Differences between the groups were not significant (P = .057). Heart rate increased significantly in both groups immediately after each intervention (P < .05). Additionally, a significant increase in oxygenation was observed from baseline to 1 h post-intervention in the ERCC+MI-E group (P < .05). Finally, several transitory hemodynamic variations occurred during both interventions, but these were nonsignificant and were considered clinically irrelevant. In mechanically ventilated subjects, MI-E combined with ERCC increased the sputum volume cleared without causing clinically important hemodynamic changes or adverse events. (ClinicalTrials.gov registration: NCT03316079.).

Airway Clearance Techniques for Mechanically Ventilated Patients: Insights for Optimization.

Secretion management in mechanically ventilated patients is a paramount task for clinicians. A better understanding of the mechanisms of flow bias and airway dynamic compression during airway clearance therapy may enable a more effective approach for this population. Ventilator hyperinflation, expiratory rib cage compression, a PEEP-ZEEP maneuver, and mechanical insufflation-exsufflation are examples of techniques that can be optimized according to such mechanisms. In addition, novel technologies, such as electric impedance tomography, may help improve airway clearance therapy by monitoring the consequences of regional secretion displacement on lung aeration and regional lung mechanics.

Effects of Manual Rib Cage Compressions on Mucus Clearance in Mechanically Ventilated Pigs.

Manual rib cage compression is a chest physiotherapy technique routinely used in clinical practice. However, scientific evidence remains scarce on the effects of manual rib cage compression on airway clearance and oxygenation in mechanically ventilated patients. Anesthetized pigs were intubated via the trachea and mechanically ventilated. To create atelectasis, artificial mucus was infused into the airway. Each pig was randomly assigned to 1 of 2 groups: closed suctioning alone (control group, 7 pigs), or manual rib cage compression combined with closed suctioning (manual rib cage compression group, 8 pigs). Hard and brief rib cage compression synchronized with early expiratory phase was tested. Mucus clearance and oxygenation were assessed after the intervention. Sequential changes of hemodynamics were assessed after the intervention. During hard manual rib cage compression, the mean ± SD peak expiratory flow increased to 44 ± 7 L/min compared with 31 ± 7 L/min without treatment (P < .001). Manual rib cage compression combined with endotracheal suctioning increased mucus clearance compared with closed suctioning alone (mucus amounts, 5.5 [3.4-9.4] g vs 0.7 [0.5-2.0] g; P = .004); however, it did not improve gas exchange and radiologic findings. There were no significant differences in hemodynamic variables between the 2 groups. Our findings indicated that hard and brief manual rib cage compression combined with closed suctioning was safe and led to improvement of mucus clearance; however, no effectiveness was confirmed with regard to oxygenation and ventilation.

Changes in ventilation mechanics during expiratory rib cage compression in healthy males.

[Purpose] The purpose of this study was to clarify the differences in ventilation mechanics between quiet breathing and expiratory rib cage compression, and between expiratory rib cage compression on the upper rib cage and on the lower rib cage. [Subjects and Methods] Subjects comprised 6 healthy males. Expiratory rib cage compression was performed manually by compressing the upper and lower rib cages. Changes in the lung volume, flow rate, and esophageal and gastric pressure were examined. [Results] The end expiratory lung volume was significantly lower during expiratory rib cage compression than at rest, but the end inspiratory lung volume was not significantly different. When compared with the esophageal and gastric pressures on the upper and lower rib cages at rest, the gastric pressures were significantly higher at end expiration. Lung resistance was significantly higher during expiratory rib cage compression than at rest. [Conclusion] Although expiratory rib cage compression promoted expiration and increased tidal volume, the lung volume did not increase beyond end inspiratory levels at rest. Lung resistance may increase during expiratory rib cage compression due to a decrease in lung volume. The mechanism by which expiration is promoted differed between the upper and lower rib cages.

Expiratory rib cage compression in mechanically ventilated adults: systematic review with meta-analysis

ObjectiveTo review the literature on the effects of expiratory rib cage compression on ventilatory mechanics, airway clearance, and oxygen and hemodynamic indices in mechanically ventilated adults.MethodsSystematic review with meta-analysis of randomized clinical trials in the databases MEDLINE (via PubMed), EMBASE, Cochrane CENTRAL, PEDro, and LILACS. Studies on adult patients hospitalized in intensive care units and under mechanical ventilation that analyzed the effects of expiratory rib cage compression with respect to a control group (without expiratory rib cage compression) and evaluated the outcomes static and dynamic compliance, sputum volume, systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, peripheral oxygen saturation, and ratio of arterial oxygen partial pressure to fraction of inspired oxygen were included. Experimental studies with animals and those with incomplete data were excluded.ResultsThe search strategy produced 5,816 studies, of which only three randomized crossover trials were included, totaling 93 patients. With respect to the outcome of heart rate, values were reduced in the expiratory rib cage compression group compared with the control group [-2.81 bpm (95% confidence interval [95%CI]: -4.73 to 0.89; I2: 0%)]. Regarding dynamic compliance, there was no significant difference between groups [-0.58mL/cmH2O (95%CI: -2.98 to 1.82; I2: 1%)]. Regarding the variables systolic blood pressure and diastolic blood pressure, significant differences were found after descriptive evaluation. However, there was no difference between groups regarding the variables secretion volume, static compliance, ratio of arterial oxygen partial pressure to fraction of inspired oxygen, and peripheral oxygen saturation.ConclusionThere is a lack of evidence to support the use of expiratory rib cage compression in routine care, given that the literature on this topic offers low methodological quality and is inconclusive.

Aprendendo a lidar com situações de emergência: treinamento de primeiros socorros para pais

As situações de urgência e emergências podem ocorrer em qualquer local fora do ambiente hospitalar e é necessário que os primeiros socorros sejam precocemente instituídos. Para isso, o treinamento das pessoas que realizarão tal atendimento e a disponibilidade e funcionalidade destes atendimentos nas escolas e em locais públicos são primordiais. Os pais da DEdIC solicitaram este treinamento para esclarecer dúvidas e aprender como agir na situação de urgência e emergência.Este trabalho visa capacitar os pais e responsáveis da DEdIC em primeiros socorros. Foram realizados cursos com treinamento em primeiros socorros com abordagem teórica e demonstração prática com duração aproximada de 3 horas abordando os seguintes conteúdos: Reconhecimento da Situação de Emergência (PCR), avaliar nível de consciência, solicitar ajuda acionando o serviço médico de emergência, avaliar posicionamento da vítima e do socorrista, avaliar pulso carotídeo, compressões torácicas e utilização de desfibriladores externos automáticos (DEA); Outras situações de primeiros socorros envolvendo quedas, ferimentos e hemorragias, fraturas, vítima engasgada, convulsão, desmaios, febre, avulsão dentária, sangramento nasal, corpo estranho nos olhos e orelhas e reações anafiláticas e picadas de insetos e outros animais no ambiente escolar. O recurso utilizado para a realização deste momento foi o multimídia além dos recursos materiais: manequins simuladores de emergência adulto, criança e bebê (LAERDAL) ® e Desfibrilador Externo Automático (DEA) Zoll®. Participaram 43 pais e responsáveis da DEdIC. Aprender como realizar os primeiros socorros com teoria e demonstração prática proporciona maior segurança e tranquilidade no momento de emergência e ações eficazes.

Expiratory rib cage compression, endotracheal suctioning, and vital signs.

Sir, We read with interest Bousarri et al.’s article which has been recently published in your journal under the title “The effect of expiratory rib cage compression before endotracheal suctioning on the vital signs in patients under mechanical ventilation.”[1] While the article is potentially of interest to readers, there are several aspects that need attention. First of all, it concerns us that all patients with PEEP were excluded from this study. The usual practice internationally is that all patients who require positive pressure ventilation have a small amount of PEEP; therefore, this raises significant issues in regard to external validity of the study as many centers would have no patients with similar treatment characteristics as those who were included in .....

Assessing respiratory contributions to f0 declination in German across varying speech tasks and respiratory demands

Many past studies have investigated the factors that affect f0 declination and its physiological underpinnings. This study assessed the relation between respiration and f0 declination by means of simultaneous acoustic and respiratory recordings of read and spontaneous speech from speakers of German. We analysed the effect of the number of syllables and voiceless obstruents within each Intonational Phrase unit. Both factors could influence the slope of f0 declination and/or rib cage movement. If respiration and f0 declination are related physiologically, their relationship might also be modulated by either or both factors. Our results show consistently, for read and spontaneous speech, that the slope of the rib cage movement is not related to f0 declination. F0 slopes are shallower in spontaneous than in read speech. F0 declination was affected by utterance length, but rib cage slope was not. Finally, although a higher number of voiceless obstruents yielded a greater rib cage compression, it did not affect f0 declination. These results suggest that although f0 declination occurs in many languages, it might not have a purely physiological origin in breathing. Other factors such as speech planning and communicative constraints might interact with physiological constraints to shape f0 declination.

Comparison of changes in tidal volume associated with expiratory rib cage compression and expiratory abdominal compression in patients on prolonged mechanical ventilation.

[Purpose] This study was designed to compare and clarify the relationship between expiratory rib cage compression and expiratory abdominal compression in patients on prolonged mechanical ventilation, with a focus on tidal volume. [Subjects and Methods] The subjects were 18 patients on prolonged mechanical ventilation, who had undergone tracheostomy. Each patient received expiratory rib cage compression and expiratory abdominal compression; the order of implementation was randomized. Subjects were positioned in a 30° lateral recumbent position, and a 2-kgf compression was applied. For expiratory rib cage compression, the rib cage was compressed unilaterally; for expiratory abdominal compression, the area directly above the navel was compressed. Tidal volume values were the actual measured values divided by body weight. [Results] Tidal volume values were as follows: at rest, 7.2 ± 1.7 mL/kg; during expiratory rib cage compression, 8.3 ± 2.1 mL/kg; during expiratory abdominal compression, 9.1 ± 2.2 mL/kg. There was a significant difference between the tidal volume during expiratory abdominal compression and that at rest. The tidal volume in expiratory rib cage compression was strongly correlated with that in expiratory abdominal compression. [Conclusion] These results indicate that expiratory abdominal compression may be an effective alternative to the manual breathing assist procedure.

Expiratory Rib Cage Compression in Mechanically Ventilated Subjects: A Randomized Crossover Trial

Expiratory rib cage compression (ERCC) has been empirically used by physiotherapists with the rationale of improving expiratory flows and therefore the airway clearance in mechanically ventilated patients. This study evaluates the acute mechanical effects and sputum clearance of an ERCC protocol in ventilated patients with pulmonary infection. In a randomized crossover study, sputum production and respiratory mechanics were evaluated in 20 mechanically ventilated subjects submitted to 2 interventions. ERCC intervention consisted of a series of manual bilateral ERCCs, followed by a hyperinflation maneuver. Control intervention (CTRL) followed the same sequence, but instead of the compressive maneuver, the subjects were kept on normal ventilation. Static (Cst) and effective (C(eff)) compliance and total (R(tot)) and initial (R(init)) resistance of the respiratory system were measured pre-ERCC (baseline), post-ERCC or CTRL (POST1), and post-hyperinflation (POST2). Peak expiratory flow (PEF) and the flow at 30% of the expiratory tidal volume (flow 30% VT) were measured during the maneuver. ERCC cleared 34.4% more secretions than CTRL (1 [0.5-1.95] vs 2 [1-3.25], P < .01). Respiratory mechanics showed no differences between control and experimental intervention in POST1 for Cst, Ceff, R(tot), and R(init). In POST2, ERCC promoted an increase in Cst (38.7 ± 10.3 vs 42.2 ± 12 mL/cm H2O, P = .03) and in C(eff) (32.6 ± 9.1 vs 34.8 ± 9.4 mL/cm H2O, P = .04). During ERCC, PEF increased by 16.2 L/min (P < .001), and flow 30% VT increased by 25.3 L/min (P < .001) compared with CTRL. Six subjects (30%) presented expiratory flow limitation (EFL) during ERCC. The effect size was small for secretion volume (0.2), Cst (0.15), and C(eff) (0.12) and negligible for R(tot) (0.04) and R(init) (0.04). Although ERCC increases expiratory flow, it has no clinically relevant effects from improving the sputum production and respiratory mechanics in hypersecretive mechanically ventilated patients. The maneuver can cause EFL in some patients. (ClinicalTrials.gov registration NCT01525121).

Early Respiratory Therapy Reduces Postoperative Atelectasis in Children Undergoing Lung Resection

Early physiotherapy reduces pulmonary complications after lung resection in adult patients. However, the effectiveness and the techniques used in postoperative physiotherapy in children undergoing lung resection have not been well described. Therefore, the standardization of a physiotherapeutic attendance after lung resection in children is necessary. This was a retrospective and prospective, interventional, descriptive, and quantitative study. We evaluated 123 pediatric subjects undergoing lung resection. Fifty-two children were prospectively submitted to a standardized physiotherapy protocol that included a mask with a positive expiratory pressure of 10 cm H2O, expiratory rib cage compression, coughing, lifting the upper limbs, and ambulation, starting within the first 4 hours after surgery and continuing 3 times each day. A historical control group of 71 subjects received physiotherapeutic techniques without specific standardization and with variability in the start date and number of days attended. We recorded the presence of postoperative complications, prolonged air leak, postoperative bronchoscopy, the time of chest tube removal, and hospital stay following surgery. The group that received a standardized protocol of physiotherapy had fewer instances of atelectasis than the control group (15.4% vs 7.6%, P = .01). Subjects in the control group were more likely than those in the intervention group to require fiberoptic bronchoscopy for bronchial toilet (n = 14 [19.7%] vs n = 5 [9.6%], P ≤ .001). There was no difference in the time of drainage or hospital stay between the groups. Implementation of a standardized physiotherapeutic protocol after lung resection in children decreases atelectasis but does not reduce the time of chest tube removal or the duration of hospital stay.

Effects of Manual Rib Cage Compressions on Expiratory Flow and Mucus Clearance During Mechanical Ventilation*

We investigated the effects of two different types of manual rib cage compression on expiratory flow and mucus clearance during prolonged mechanical ventilation in pigs. Prospective randomized animal study. Animal research facility, University of Barcelona, Spain. Nine healthy pigs. Pigs were tracheally intubated, sedated, paralyzed, and mechanically ventilated. The animals were prone on a surgical bed in the anti-Trendelenburg position. The experiments were carried out at approximately 60 and 80 hrs from the beginning of mechanical ventilation. Two types of manual rib cage compressions were tested: Hard and brief rib cage compressions synchronized with early expiratory phase (hard manual rib cage compression) and soft and gradual rib cage compressions applied during the late expiratory phase (soft manual rib cage compression). The interventions were randomly applied for 15min with a 15-min interval between treatments. Respiratory flow and mucus movement were assessed during the interventions. Respiratory mechanics and hemodynamics were assessed prior to and after the interventions. Peak expiratory flow increased to 60.1±7.1L/min in comparison to 51.2±4.6L/min without treatment (p < 0.0015) and 48.7±4.3L/min with soft manual rib cage compression (p = 0.0002). Similarly, mean expiratory flow increased to 28.4±5.2L/min during hard manual rib cage compression vs. 15.9±2.2 and 16.6±2.8L/min without treatment and soft manual rib cage compression, respectively (p = 0.0006). During hard manual rib cage compression, mucus moved toward the glottis (1.01 ± 2.37mm/min); conversely, mucus moved toward the lungs during no treatment and soft manual rib cage compression, -0.28 ± 0.61 and -0.15±0.95mm/min, respectively (p = 0.0283). Soft manual rib cage compression slightly worsened static lung elastance and cardiac output (p = 0.0391). Hard manual rib cage compression improved mucus clearance in animals positioned in the anti-Trendelenburg position. The technique appeared to be safe. Conversely, soft manual rib cage compression was not effective and potentially unsafe. These findings corroborate the predominant role of peak expiratory flow on mucus clearance.

Esophageal pressure as an estimate of average pleural pressure with lung or chest distortion in rats

Pressure–volume curves of the lungs and chest wall require knowledge of an effective ‘average’ pleural pressure (Pplav), and are usually estimated using esophageal pressure as Ples–V and Pwes–V curves. Such estimates could be misleading when Ppl becomes spatially non-uniform with lung lavage or shape distortion of the chest. We therefore measured Ples–V and Pwes–V curves in conditions causing spatial non-uniformity of Ppl in rats. Ples–V curves of normal lungs were unchanged by chest removal. Lung lavage depressed PLes–V but not Pwes–V curves to lower volumes, and chest removal after lavage increased volumes at PL≥15cmH2O by relieving distortion of the mechanically heterogeneous lungs. Chest wall distortion by ribcage compression or abdominal distension depressed Pwes–V curves and Ples–V curves of normal lungs only at Pl≥3cmH2O. In conclusion, Pes reflects Pplav with normal and mechanically heterogeneous lungs. With chest wall distortion and dependent deformation of the normal lung, changes of Ples–V curves are qualitatively consistent with greater work of inflation.