Pain from propofol injection is a common problem, the cause of which is unknown. The chemical properties of propofol, the preparation method, the mechanism of causing pain and the clinical strategy of preventing pain after propofol injection were reviewed in order to understand this topic.
Propofol (diisopropyl phenol) is a popular inducer of intravenous anesthesia, especially for brief cases, day surgery, or when using a laryngeal mask airway. Propofol can also be used in total intravenous anesthesia (TIVA) techniques to maintain anesthesia and sedation. It is also used to prevent vomiting [1], intubate the trachea without neuromuscular blockers [2], and treat itching [3,4]. Pain during propofol injections is a common problem and can be very painful for patients. The incidence of pain during anesthesia induction in adults ranges from 28% to 90% and can be severe [5,6]. In children, the incidence of pain is between 28% and 85% [7,8]. The younger the child, the higher the incidence and severity of pain from propofol injections [9]. This may be due to smaller veins in children. There was no gender difference in the incidence of pain from propofol injection. The incidence of pain during propofol injection is high compared to other intravenous anesthetics. The incidence of pain induced by thiopentone is about 7%[5], while the incidence of pain induced by methylhexanone is between 12% and 64%[10,11]. The pain rate of diazepam injection in the organic solvent propylene glycol (Diazepam) was 37%, but when diazepam was reformulated in soybean oil (diazepam), the pain rate became 0%[10]. 1% midazolam rarely experienced injection pain. The incidence of pain after etomidate administration was between 24% and 68%.
