The impact of a patient trolley's intra-hospital speed and position on the quality of ventilation performed by a self-inflating bag.

Purpose: The aim of the study is to make a quantitative and qualitative assessment of selected parameters connected with a patient's ventilation using a self-inflating bag during simulated 'head-first' or ‘legs-first' directions of patient transport. Methods: Seventeen people participated in the conducted study. Their task included conducting alternative ventilation during the transport of the patient (Airway Management Simulator BT Inc.) by using the head or the legs technique: in the transport trolley's movement direction. At all times during the transport, video recording was carried out non–stop, and the spectrum of generated vibrations was recorded using the SVAN 958 vibration spectrum analyser, with a three-direction SVANTEK SV 39A disc for measuring whole body vibrations. Additionally, a survey was carried out. The task of the research participants was to indicate the degree of performer comfort related to the ventilation and the transport process. The assessment of the results was then subjected to statistical analysis. Results: The duration of the patient transport by using the legs-first technique was shorter (57.5 s on average) in comparison with the head-first one (62.5 s on average). The subjective assessment of performer comfort on the transport and ventilation process with the legs-first technique was perceived as higher compared to the head-first one. During the patient transport, the highest a RMS acceleration values in the vertical direction were obtained for frequencies 8-25 [Hz], corresponding to the resonance frequencies of the head (17-25 Hz), trachea and bronchi (12-16 Hz), lungs (4-11 Hz) and the spine (8-12 Hz). According to other authors, vibrations with a frequency of 8-10 Hz lead to a decrease in blood pressure, bradycardia and bradypnoe; vibrations at a frequency of 11-12 Hz cause increased heart rate, peripheral vasoconstriction, fatigue, abnormal temperature, nausea, abdominal and chest pain, while vibrations above 12 Hz cause dangerous arrhythmia, muscle tremors, pain and bleeding. Conclusions: The recommended position of intra-hospital patient transport is the legs-first technique. At the stage of preparation for transport, it is necessary to keep in mind the ergonomic aspects of carrying out possible rescue procedures, e.g. artificial ventilation, the effectiveness of which depends on the height of the patient’s trolley, the elbow-shoulder angle of the paramedic, and their back inclination in the thoracolumbar section. The training of medical staff should include conducting high fidelity simulation of activities connected with e.g. transport, enabling future paramedics to acquaint themselves with the working conditions in terms of the effectiveness of actions and ensuring adequate work ergonomics.