Early findings:
(1) tachypnea
(2) hypertension and tachycardia
(3) lightheadedness, headache, dizziness, giddiness and confusion
(4) nausea and vomiting
(5) suffocation
Later findings:
(1) respiratory depression without cyanosis
(2) bright red venous blood
(3) profound metabolic acidosis with lactic acidosis and increased serum anion gap
(4) breath smelling of bitter almonds
(5) CNS depression, with stupor, coma, opisthotonus, and convulsions
(6) cardiovascular depression with bradycardia, hypotension, and arrhythmias
(7) fixed dilated pupils
(8) skin cold and clammy with diaphoresis (copious sweating)
Combinations of findings that are highly suggestive:
(1) respiratory depression without cyanosis
(2) rapid onset of coma and metabolic acidosis
