In order to test the possibility that the muscular twitching seen after succinylcholine might produce changes in intragastric pressure, the intragastric pressure of 43 adult patients anesthetised for elective surgery were measured before giving succinylcholine, during the period of twitching and after twitching had subsided.
Intragastric pressure was measured by means of passing a plastic stomach tube (No. 12 EG for adult) into stomach and connecting the other end to a water manometer.
Among the 43 cases, 9 patients showed a clear increase in intragastric pressure (7~9 cm/H₂O), 21 patients showed slight increase (1~4 cm/H₂O), remaining 13 patients showed no change or a sligth decrease (1~2 cm/H₂O).
Twenty three patients in this series manifested pronounced twitching and the remaining 19 patients showed only moderate twitching. However, of the 23 patients with marked twitching, only 15 patients showed an increase in intragastric pressure (1~9cm/ H 0). It would therefore appear that marked twitching do not always produce a rise in intragastric pressure.
Following the administration of succinylcholine, 9 patients out of 43 exhibited an increased intragastric pressure at the time of pronounced twitching. Thus, succinylcholine may be a factor in the production of regurgitation during induction of anesthesia. The increase in intragastric pressure is attributed to the contractions of the muscle in the abdominal wall.
It is felt that succinylcholine is not a suitable muscle relaxant even the head-up induction is being used to safeguard the patient against regurgitation, because of a sufficiently high intragastric pressure overcoming the 20 cm/H₂O of competence of the cardia.
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