Paediatricsmiddle twist
An 18-month-old boy is brought to a rural emergency department after being found in a farm shed beside a spilt container, with his clothing wet. He is drowsy but rousable. His pupils are 1 mm, his shirt and axillae are soaked with sweat, saliva is pooling in his mouth, and there are widespread wheezes with coarse crackles. His heart rate is 55 per minute and he has been incontinent of urine and faeces. Which one of the following agents best accounts for these findings?