Premedications-the pain perceived by the patientdurina bone marrow biopsy pero ed underlocal anesthesia is lo vto moderate being approx on a 0 to 10 scale in one stu dy [20]and 1.7 on a0 to5 scale in another [21].While premedications,including anxiolytics or opiates. are notusually necessary [221.certain individuals with underlving dense bone structure.pain issues.or those with heightened anxiety may benefit from the use of such agents.It cannot be overstated that the quality of the specimen obtained may be stly superior in cooperativ e and com patient. In children with procedure phobias,the use of lorazepam under carefully dnican be very beneficial.producing bothreax antegrade zepan n or trama may na nilar adults with anxiety [23-26].This can be particularly helpful if the child or anxious adultis likely to require multiple bone marrow evaluations over a period of time,as in the treatment of acute leukemia.A safe conscious sedation policy should be in place prior to using drugs such as benzodiazepines or opioids in patients of any age The use of inhaled nitrous oxide and oxvaen.an established combination used for pain management and sedation in certain gynecologicprocedures well-tole erated and effective for u se during bone marrow aspiration and biopsy:use of this agent may diminish the risk of prolonged sedation associated with benzodiazepine or opioid dosing [27-29]. However,given the limited nature of these studies,further research may be required before the use of nitrous oxide/oxygen is accepted into standard practice Any premedications should be administered in a timely fashion,prior to Use of an assistant-Bone marrow aspirates and biopsies often clot within minutes of being ained.During this time, h n perf the procedure may still be busy performing an aspiration or biopsy at the same or another site,reassuring the patient,or initiating local hemostasis.Ideally, bone marrow aspiration and biopsy be carried out with the help of a trained pare the slides and specimens or who assist tant who can either nepp completion of the procedure. in achieving adequate hemos Needle selection-Disposable aspiration and biopsy needles are preferred in order to guarantee sterility and sharpness,as well as to reduce procedure- and"failure"rat [301 Allc vailable needles are lfor piraion and biopy ofcrestForste the needle should have a guard which screws securely to a selected portion of the needle in order to limit its penetration(see'Stemal aspiration'below). Premedications — The pain perceived by the patient during bone marrow aspiration and biopsy performed under local anesthesia is low to moderate, being approximately 3 on a 0 to 10 scale in one study [20] and 1.7 on a 0 to 5 scale in another [21]. While premedications, including anxiolytics or opiates, are not usually necessary [22], certain individuals with underlying dense bone structure, pain issues, or those with heightened anxiety may benefit from the use of such agents. It cannot be overstated that the quality of the specimen obtained may be vastly superior in a cooperative and comfortable patient. In children with procedure phobias, the use of lorazepam under carefully controlled conditions can be very beneficial, producing both relaxation and antegrade amnesia; lorazepam or tramadol may have a similar effect in adults with anxiety [23-26]. This can be particularly helpful if the child or anxious adult is likely to require multiple bone marrow evaluations over a period of time, as in the treatment of acute leukemia. A safe conscious sedation policy should be in place prior to using drugs such as benzodiazepines or opioids in patients of any age. The use of inhaled nitrous oxide and oxygen, an established combination used for pain management and sedation in certain gynecologic procedures and in sigmoidoscopy, is both well-tolerated and effective for use during bone marrow aspiration and biopsy; use of this agent may diminish the risk of prolonged sedation associated with benzodiazepine or opioid dosing [27-29]. However, given the limited nature of these studies, further research may be required before the use of nitrous oxide/oxygen is accepted into standard practice. Any premedications should be administered in a timely fashion, prior to performing the procedure, in order to allow for the desired effects [25,26]. (See "Procedural sedation in children outside of the operating room".) Use of an assistant — Bone marrow aspirates and biopsies often clot within minutes of being obtained. During this time, the person performing the procedure may still be busy performing an aspiration or biopsy at the same or another site, reassuring the patient, or initiating local hemostasis. Ideally, bone marrow aspiration and biopsy be carried out with the help of a trained assistant who can either help prepare the slides and specimens or who assist in achieving adequate hemostasis following completion of the procedure. Needle selection — Disposable aspiration and biopsy needles are preferred in order to guarantee sterility and sharpness, as well as to reduce procedure￾related pain and "failure" rates [30]. All commercially available needles are acceptable for aspiration and biopsy of the iliac crest. For sternal aspiration, the needle should have a guard which screws securely to a selected portion of the needle in order to limit its penetration (see 'Sternal aspiration' below)