Airway and body surface sensors for triggering in neonatal ventilation

Abstract

Failure of neonatal patient triggered ventilation may reflect a delay in delivery of flow relative to the inspiratory effort of the infant. Transmission of diaphragmatic contraction to the sensor site (patient delay) and further transmission to and within the sensing device (device delay) both contribute to the delay in triggering. Patient and device delays were studied for different sensing systems in 36 infants, 24 of whom were intubated. Device delay was long (> 40 ms) with a conventional apnoea monitor compared with sensors placed at the airway opening (2 ms), the inspiratory (12 ms) and expiratory (3 ms) pressure transducers of the ventilator, the Graseby capsule (8 ms), strain gauges (3 ms) and oesophageal pressure (6 ms). In near normal infants, the sum of patient and device delays for the latter sensors was less than 20 ms and a minor component of the total delay. However, in severe lung disease the total delay may be more than 100 ms even for airway sensors.

Synchronized neonatal non-invasive ventilation-a pilot study: The graseby capsule with bi-level NCPAP

“…Hird and Greenough found a decreased sensitivity of the GC compared to the airway pressure trigger, and a longer trigger delay. However, John et al found the GC to have a faster response time in the presence of severe lung disease and suggested that the GC may be quite useful for NIV.…”

Practices of use of nasal intermittent positive pressure ventilation (NIPPV) in neonatology in northeastern Brazil

“…Apesar desta afirmativa, apenas uma das unidades descreveu a cápsula abdominal como meio de detectar o esforço inspiratório do recém-nascido; as demais referiram-se à sensibilidade promovida pelo aparelho de VPM convencional como meio de sincronização. Este mecanismo adotado para sincronização tem sido considerado inadequado para recém-nascidos, sobretudo quando em VPPIN, considerando-se a dificuldade de detecção do esforço respiratório em virtude dos grandes vazamentos através das interfaces [16][17][18] . Acredita-se, desta forma, que a maior parte das instituições do Nordeste brasileiro possua dificuldades quanto ao fornecimento de VP-PIN verdadeiramente sincronizada com o esforço inspiratório dos recém-nascidos, o que impede a aplicação de maneira segura dos resultados de estudos sobre a eficácia do uso de VPPIN, uma vez que, em sua maioria, foram realizados no modo sincronizado 8,19,20 .…”

Aerosol delivery to ventilated newborn infants: historical challenges and new directions

“…Moreover, flow and pressure-based sensors can be damaged by aerosols, and their placement within the aerosol flow and in close proximity to the patient is not advisable. However, there are other technologies that can be used for breath-synchronized nebulization such as Graseby pneumatic capsule (Graseby Dynamics Ltd., Watford, UK) [40] or neurally adjusted ventilator assist technology (Maquet Inc., Bridgewater, NJ, USA) [65]. Neither of these methods requires sensors placed within the ventilator tubes and thus do not cause additional risks for aerosol impaction.…”