Optimum Insufflation Capacity in NMD

Patients with underlying neuromuscular disorder (NMD) often suffer from weakness in the inspiratory and expiratory muscles. Consequently they do not have the strength to generate the minimum flow of 160 to 300 liters/minute for an efficient cough function. The restricted cough function allows secretion to accumulate, which in turn causes narrowing of the airway lumen and makes ventilation of the neuromuscular patient even more difficult. The patient's susceptibility to infection increases again and the vicious circle repeats itself. Severe secretion retention may even lead to ventilator failure. Effective secretion and cough management instead reduces the risk for stay in hospital. Therefore, secretion and cough management is a mandatory part of the therapeutic concept for treating patients with neuromuscular disease.

The therapeutic efficacy of the Lung Insufflation Assist Maneuver(LIA) integrated in the ventilator VENTIlogic LS-plus manufactured by Weinmann GmbH+Co KG was studied in a pilot study carried out by the Dep. for Pediatric Pulmonology and Sleep Medicine at the University Hospital of Essen/Germany in cooperation with Research & Development at Weinmann GmbH &Co KG, Germany . The objective of the pilot study was to examine the therapeutic efficacy of LIAM as a cough support function in patients with neuromuscular disease and indications for mechanical ventilation.

We hypothesized that i) a certain insufflation maneuver pressure may be optimal to achieve the highest individual peak cough flow and ii) that this pressure is below the pressure needed to achieve the maximum insufflation capacity. We define the lowest insufflation capacity at which the best individual PCF can be achieved as optimum insufflation capacity (OIC). The study was performed using two different techniques in order to demonstrate that findings are not dependent on maneuver details but are rather based on effects of maneuver pressure. The protocol was limited to techniques which do not require breath stacking: i) insufflation with an Intermittend Positive Pressure (IPPB) device and ii) with the VENTIlogic LS using LIAM.