Cough-assist Devices Research Articles

Effect of Cough Assist Device on Hemodynamic Status and Oxygen Saturation for Ventilated Children

Effect of Cough Assist Device on Hemodynamic Status and Oxygen Saturation for Ventilated Children

Computational Modelling of Cough Function and Airway Penetrant Behavior in Patients with Disorders of Laryngeal Function.

Objective/HypothesisPatients with laryngeal disorders often exhibit changes to cough function contributing to aspiration episodes. Two primary cough variables (peak cough flow: PCF and compression phase duration: CPD) were examined within a biomechanical model to determine their impact on characteristics that impact airway compromise.Study DesignComputational studyMethodsA Computational Fluid Dynamics (CFD) technique was used to simulate fluid flow within an upper airway model reconstructed from patient CT images. The model utilized a finite‐volume numerical scheme to simulate cough‐induced airflow, allowing for turbulent particle interaction, collision, and break‐up. Liquid penetrants at 8 anatomical release locations were tracked during the simulated cough. Cough flow velocity was computed for a base case and four simulated cases. Airway clearance was evaluated through assessment of the fate of particles in the airway following simulated cough.ResultsPeak‐expiratory phase resulted in very high airway velocities for all simulated cases modelled. The highest velocity predicted was 49.96 m/s, 88 m/s, and 117 m/s for Cases 1 and 3, Base case, and Cases 2 and 4 respectively. In the base case, 25% of the penetrants cleared the laryngeal airway. The highest percentage (50%) of penetrants clearing the laryngeal airway are observed in Case 2 (with −40% CPD, +40% PCF), while only 12.5% cleared in Case 3 (with +40% CPD, −40% PCF). The proportion that cleared in Cases 1 and 4 was 37.5%.ConclusionAirway modelling may be beneficial to the study of aspiration in patients with impaired cough function including those with upper airway and neurological diseases. It can be used to enhance understanding of cough flow dynamics within the airway and to inform strategies for treatment with “cough‐assist devices” or devices to improve cough strength.Level of EvidenceN/A.

Home Mechanical Ventilation: An Overview.

Prevalence studies have shown heterogeneous use of home mechanical ventilation in different conditions, with a marked increase in uptake especially in users of noninvasive ventilation. Although randomized controlled trials have examined noninvasive ventilation in acute exacerbations of chronic obstructive pulmonary disease, for weaning from invasive ventilation and for postextubation respiratory failure, the evidence base for long-term noninvasive ventilation and comparisons with invasive ventilation are less well developed. The combination of noninvasive ventilation and cough-assist devices has reduced the indications for tracheotomy ventilation in some situations (e.g., Duchenne muscular dystrophy, spinal muscular atrophy, myopathies, and amyotrophic lateral sclerosis) and has also prolonged survival. Several excellent overviews have been written on the history of home mechanical ventilation and its evolution from negative pressure to positive pressure techniques, including a systematic review of outcomes. This review, instead, will cover recent trials, trends in the field, outcomes, and safety. Because the greatest growth has been in home noninvasive ventilation, this will be the main focus of this article.

Successful weaning from mechanical ventilation in the quadriplegia patient with C2 spinal cord injury undergoing C2-4 spine laminoplasty -A case report-

In patients with cervical spine injuries, respiratory function requires careful attention. Voluntary respiratory control is usually possible with lesions below C4 level although paralysis of the abdominal musculature results in a decreased ability to cough and to clear secretions, which may later lead to respiratory insufficiency. Therefore, injuries above C5 usually necessitate long term mechanical ventilation. Even though weaning criteria are not definitive for the quadriplegic patient, M-mode ultrasonography of the diaphragm may be useful in identifying patients at high risk of difficulty weaning. Diaphragmatic dysfunction (vertical excursion < 10 mm or paradoxical movements) results in frequent early and delayed weaning failures. We present our clinical experience with successful weaning by using M-mode ultrasonography and a cough-assist device for secretion clearance after extubation in a quadriplegic patient undergoing C2-4 spine laminoplasty.

Comparison of Alpha 200 and CoughAssist as Intermittent Positive Pressure Breathing Devices: A Bench Study

Intermittent positive pressure breathing (IPPB) is used in non-intubated patients to increase lung volume and to enhance coughing. Alpha 200 (Salvia Lifetec, Kronberg, Germany) is a specific IPPB device. CoughAssist (Respironics France, Carquefou, France) is a mechanical insufflator-exsufflator used to remove secretions in patients with inefficient cough. Both can also be used for intubated or tracheotomized patients. We assessed the impact of various artificial airways on the ability of the Alpha 200 and CoughAssist to generate insufflated volume. We measured the insufflated volume and pressure at the airway opening in a lung model under 2 conditions of compliance (30 or 60 mL/cm H(2)O) at single resistance of 5 cm H(2)O/L/s. The devices were used at 2 set pressures: 30 and 40 cm H(2)O. The Alpha 200 was set at 2 inflation flows: 0.5 and 1 L/s, whereas CoughAssist was set at its highest value of 10 L/s. Measurements were done without (control) and with different size endotracheal tubes and tracheostomy cannulae. The relationships between insufflated volume and measured pressure were analyzed using linear regressions. The slopes and intercepts of the control relationship between insufflated volume and pressure were significantly greater with Alpha 200 at each set flow than with CoughAssist. As artificial airways were used, the insufflated volume did not differ from the control with CoughAssist, while with Alpha 200 it increased at each flow setting and for all mechanical conditions. The largest differences in insufflated volume between the 2 devices were observed for the largest endotracheal tubes and tracheostomy cannulas and for the lowest inflation flow setting in Alpha 200. These results can be explained in terms of how the devices function, as CoughAssist adapts by increasing flow, while Alpha 200 adapts by increasing inspiratory time. This bench study has shown that in the presence of artificial airways the value of the insufflated volume generated by the CoughAssist device was significantly lower than that generated by the Alpha 200 device.

Pulmonary complications of chronic neuromuscular diseases and their management.

Chronic neuromuscular diseases may affect all major respiratory muscles groups including inspiratory, expiratory, and bulbar, and respiratory complications are the major cause of morbidity and mortality. Untreated, many of these diseases lead inexorably to hypercapnic respiratory failure, precipitated in some cases by chronic aspiration and secretion retention or pneumonia, related to impairment of cough and swallowing mechanisms. Many measures are helpful including inhibition of salivation, cough-assist techniques, devices to enhance communication, and physical therapy. In addition, ventilatory assistance is an important part of disease management for patients with advanced neuromuscular disease. Because of its comfort, convenience, and portability advantages, noninvasive positive pressure ventilation (NPPV) has become the modality of first choice for most patients. Patients to receive NPPV should be selected using consensus guidelines, and initiation should be gradual to maximize the chances for success. Attention should be paid to individual preferences for interfaces and early identification of cough impairment that necessitates the use of cough-assist devices. For patients considered unsuitable for noninvasive ventilation, invasive mechanical ventilation should be considered, but only after a frank but compassionate discussion between the patient, family, physician, and other caregivers.