Is external high frequency oscillation in the treatment of organophosphate poisoning in cats a useful and easily applied method for prehospital ventilatory support?

Background: Rapid institution of ventilatory support is mandatory in apneic victims of nerve agents (NA) if fatal outcome is to be avoided. The Hayek oscillator™ (HO)-a high frequency external ventilator can provide non-invasive ventilatory support based on a cuirass tightly fit around the patient chest. Our aim was to investigate the feasibility of provision of resuscitative ventilatory support using the HO to cats poisoned by Dichlorovos (DDVP) an OP and NA-like compound. Material/Methods: DDVP, 150 mg/kg was administered per os to 10 cats. With the appearance of the first signs of intoxication, the animals were treated with atropine 0.1 mg/Kg. Then, animals were randomly divided into two equal groups: 1) control (no further treatment) or 2) experimental: ventilation using the HO with the following setup: 240 cycles/min, inspiratory and expiratory pressure of -22 and -2 cm H₂O respectively and I/E ratio of 1/1. Results: The control cats died within 4-9 min from the initial appearance of signs of systemic poisoning. The experimental 5 cats survived and regained spontaneous breathing ventilation 3 hr thereafter. The use of the HO enabled also clearance of bronchial secretion saving the need for active suctioning of the airways. Conclusions: The provision of external high frequency oscillation using the HO may serve as a useful and easily applied mode of ventilation in case of urgent need to resuscitate mass casualties suffering from NA poisoning in the prehospital setting. Its advantages include: lack of need for laryngoscopy and intubation and enhanced clearance of secretions.