Efficacy of different fluids preload on propofol injection pain: A randomized, controlled, double-blinded study

Abstract

Injection pain of propofol remains a common clinical problem. Previous studies demonstrated that propofol injection pain was alleviated by applying nitroglycerin ointment to the skin of injection site, which inspires us to test whether venous vasodilation induced by fluid preload could alleviate the pain. Different types or volumes of fluid preload were compared. 200 ASA I-II adult patients were randomly assigned to five groups of 40 each. A 20 G cannula was established on the dorsum or wrist of the hand. When fluid preload given with Plasma-Lyte A 100 mL (P100 group), 250 mL (P250 group), 500 mL (P500 group), 0.9% saline 500 mL (N500 group) or Gelofusine 500 mL (G500 group) was completed within 30 min, respectively, Propofol (0.5 mg/kg, 1%) was injected at a rate of 0.5 mL/s. A blind investigator assessed the pain using a four-point scale. Incidence of pain in P100, P250, and P500 groups was 87.5%, 57.5% and 35%, respectively (P<0.05). The median pain intensity score was significantly lower in P500 group than that in P250 and P100 groups (P<0.05 and P<0.01, respectively). Comparison of the effect of different types of solution preload indicated that the highest incidence of pain was in N500 group (62.5%) (N500 vs. P500, P=0.014; N500 vs. G500, P=0.007). The median pain intensity score in N500 group was higher than that in P500 group (P<0.05) and G500 group (P<0.05). There was no significant difference between P500 and G500 groups. It is suggested that Plasma-Lyte A or Gelofusine preload with 500 mL before propofol injection is effective in alleviating propofol-induced pain.

0.9% NaCl (Normal Saline) – Perhaps not so normal after all?

“…Normal saline increased pain, whereas Plasma-Lyte A mitigated the pain of propofol infusion in a dose dependent manner. [31] This finding is consonant with other data demonstrating vascular dysfunction and inflammation after normal saline infusion, as compared with buffered crystalloid.…”

Basal Forebrain Cholinergic Activity Modulates Isoflurane and Propofol Anesthesia

“…We also discovered that continuous isoflurane gradually inhibits the activity of cholinergic neurons in the induction period, and LORR occurred when the activity reduced to a certain level. However, for propofol anesthesia, we noticed that the injection of propofol causes a brief and slight activation of BF cholinergic neurons; this is likely on account of the direct stimulation of injection pain or signal transmission from other pain sensation-related brain regions (Yuan et al, 2016;Luo T. et al, 2018). In spite of this, the event of BF cholinergic neurons is rapidly and continuously inhibited during propofol anesthesia.…”

Parabrachial Neurons Promote Behavior and Electroencephalographic Arousal From General Anesthesia

“…It takes approximately 20 s for propofol injection to induce LORR; therefore, we set 20 s before LORR (-20–0 s) as the period from the moment propofol was given to loss of reaction. The Ca 2+ signal acutely increased after propofol injection ( p = 0.0016, paired t -test) that may be due to the acute pain sensation caused by propofol injection (Yuan et al, 2016). A significant decrease of the Ca 2+ signal was noted in anesthesia period 1 and 2; however, no significant decrease of Ca 2+ signal was observed during the early period of anesthesia (0–20 s) ( p = 0.5705, paired t -test), suggesting that the PBN neurons are suppressed in the anesthesia phase but may not be an initial decisive factor for propofol-induced unconsciousness.…”

“…Using a calcium fiber photometry system, we recorded the activity changes of PBN neurons during the induction and emergence of anesthesia. Interestingly, the propofol injection through the caudal vein immediately elicited an abrupt increase, other than decrease in Ca 2+ signaling in PBN neurons, which was possibly caused by the injection pain commonly seen in propofol application (Yuan et al, 2016), as PBN neurons are crucial for itch and pain signaling (Missig et al, 2014; Mu et al, 2017). Moreover, there was no increase in isoflurane induction.…”