Evaluation of isoflurane inhalation -anesthesia machines available in Switzerland for on farm piglet -castrations

Abstract

The present study analyzed piglet castration under isoflurane anesthesia in ten farms. The data of 202 male piglets in the age between three to eleven days and with a body weight of 1 - 4,7 kg were collected. The aim of this study was to compare the PorcAnest®, Pignap® and Pigsleeper® anesthesia machines used in Switzerland. Isoflurane, carbon dioxide (CO2) and oxygen (O2) values were measured in relation to their significance for anesthesia quality. Therefore, preoperative stress level and movements were assessed during skin incision and the dissection of the spermatic cords. Isoflurane, CO2 and O2 values were recorded in the inhaled and exhaled gases next to the nostrils at 30, 60, 75 and 90 seconds after the start of anesthesia. Movements to the skin incisions and dissection of the spermatic cord were observed in 32 % and 37 % respectively. Movements increased with the decrease of measured inspiratory and expiratory isoflurane values (FIIso and ETIso). Significantly lower inspiratory O2 values (FIO2: 12 - 21 volume % vs 21 - 95 volume %) and stronger movements were measured in anesthesia machines using room air compared to machines operated with medical oxygen. Results indicate a potential for improvement in anesthesia deph piglet castration under isoflurane inhalaton anesthesia and THE measured isoflurane, CO2 and O2 values differ significantly between PorcAnest®, Pignap® and Pigsleeper® anesthesia machines. These fluctuations could be recognized and reduced by annual professional maintenance and / or the addition of an anesthetic gas analyzer. In addition, a change to medical oxygen is indicated for all anesthetic machines. Anesthesia machines have to be optimized in consultation with the manufacturers as soon as possible and the farmers have to be trained and sensitized to ensure pain-free castration.