AbstractsBiology & Animal Science

Background: Bone marrow aspiration and/or biopsy (BMAB) is a procedure used to diagnose and follow up various haematological diseases. It is usually performed at either the sternum or the iliac crest. The procedure often causes pain despite local infiltration anaesthesia. The objective of this study was to evaluate different means of pain relief during BMAB in adult patients. Special attention was paid to pre-procedural anxiety and its effect on pain. The commonly used local anaesthetic lidocaine was compared with articaine, an anaesthetic known for its ability to penetrate bone tissue. The effect of warming and buffering the lidocaine solution, measures expected to improve the anaesthetic action, was examined. Also investigated were sublingual fentanyl and inhaled 50% nitrous oxide (N2O) in oxygen (O2) as means of analgesia and sedation during BMAB. Patients: The patient population comprised 646 adult outpatients from the Department of Haematology, Helsinki University Central Hospital, Finland. Patients were randomized to treatment groups in trials comparing one intervention with another or with placebo. The studies were all patient-blinded. One study was observational and investigated the association between pain and pre-procedural anxiety. Patient recruitment was performed between 2007 and 2014. Main results: Pre-procedural anxiety intensified pain during BMAB in all trials. Median NRS (Numeral Rating Scale, 0 = no pain, 10 = worst pain imaginable) during infiltration was 3.0 (range 0 10, interquartile range (IQR) 3.0), puncture 2.0 (range 0 10, IQR 3.0), aspiration 4.0 (range 0 10, IQR 4.0), biopsy 4.0 (range 0 10, IQR 4.0) and immediately after BMAB 0 (range 0 9.0, IQR 1.0). Scores of 8 10 comprised 8.1%, 4.7%, 13.9%, and 12.4% of the scores for infiltration, puncture, aspiration and biopsy, respectively. Possible supplemental analgesia or sedation given on patient request in addition to local anaesthesia and study intervention did not lower pain scores during BMAB. Articaine was not found to be superior to lidocaine as a local anaesthetic. Warming and buffering the lidocaine solution diminished pain during infiltration, but did not lower the pain scores during other phases of BMAB. Sublingual fentanyl (200 µg or 100 µg) did not provide significant pain relief relative to placebo when administered 6 64 minutes before BMAB. Dizziness was a frequent side-effect. Inhalation of 50% N2O in O2 was no more effective than inhalation of 50% O2. No significant differences in adverse effects emerged between patients receiving N2O/O2 and those receiving 50% O2. Interestingly, 86% of N2O patients and 83% of placebo patients would choose the same analgesia method during their next BMAB. Conclusions: Many patients undergoing BMAB suffer intense pain during the procedure. Pre-procedural anxiety was strongly associated with pain during the various phases of BMAB. The pain from local anaesthetic infiltration with articaine and lidocaine was similar. Buffering and warming the local anaesthetic solution…