Premium
Experimental and Clinical Evaluation of High‐Frequency Positive‐Pressure Ventilation (HFPPV) and the Pneumatic Valve Principle in Bronchoscopy under General Anaesthesia
Author(s) -
Eriksson Ivan,
Sjöstrand Ulf
Publication year - 1977
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1977.tb01264.x
Subject(s) - medicine , insufflation , oxygenation , anesthesia , ventilation (architecture) , bronchoscopy , general anaesthesia , surgery , mechanical engineering , engineering
A technique for automatic ventilation in bronchoscopy under general anaesthesia was evaluated in two types of lung model and in 23 patients (29–70 y) submitted for routine bronchoscopy. The technique uses high‐frequency positive‐pressure ventilation (HFPPV) and functions with a pneumatic valve derived from the bronchoscope's side‐arm. This technique has been given the name bronchoscopic HFPPV. Based on earlier studies, an insufflation frequency (f) of 60 per min and a relative insufflation time (1%) of 22 % was used. In the lung models, the relationship between the total gas input (V tot ) delivered to the side‐arm of the bronchoscope and the pressure/gas flow pattern created at the different openings of the bronchoscope was studied. The force created by the pneumatic valve function is regulated by adjustment of V tot and implies a great ventilatory reserve capacity. No air entrainment occurs through the proximal opening of the bronchoscope, which implies full control of the anaesthetic gas mixture delivered to the patient. Many of the patients were considered to be high anaesthetic risks and in the patient study it is shown that the alveolar ventilation can be fully controlled by adjustment of V TOT and arterial oxygenation by adjustment of the oxygen concentration of the oxygen/nitrous oxide mixture delivered to the side‐arm of the bronchoscope. Experimental and clinical evaluation shows that adequate oxygenation and ventilation can be achieved: —(a) over long periods of time, (b) in anaesthetic high risk patients, (c) with the bronchoscope in the main bronchus of the diseased lung, and (d) during instrumentation through the bronchoscope.A simple ventilation‐nomogram for clinical use is proposed. Adequately used, this nomogram guarantees safe ventilation during bronchoscopic HFPPV. An F IO2 of 0.3–0.4 gives adequate arterial oxygenation.