Patient aged 13 years and 11 months with a personal history of thyroglossal cyst operated on at the age of 2 years, obesity under study, who manifested since 2 months before admission: asthenia, headache, anorexia, frequent epistaxis and tachycardia after physical exercise. Examination revealed cutaneous and mucosal pallor, laterocervical and submandibular lymphadenopathy, splenomegaly measuring 6 cm and hepatomegaly measuring 2 cm. Various complementary examinations were requested, including the following: Ht: 28.3%; Hb: 7.2 g/dl; leukocytes: 235,600 mm3 (L 83.8%, M 1.1%, N 2%, E 0.1%, B 7.9%); platelets: 24,000 mm3; ESR: 70 mm/h; LDH: 1,686 U/l; uric acid: 8.3 mg/dl; ferritin: 151 ng/dl. In view of the patient's clinical and analytical evolution, a haematological neoplastic process was suspected and a bone marrow aspirate was performed in which 97% of blasts were observed, with marrow infiltration of blast elements. After completing the cytogenetic, molecular, serological, microbiological and immunological studies, a diagnosis of acute lymphoblastic leukaemia (ALL), FAB type L2 was made. Chemotherapy was started according to the SHOP 99 protocol for very high-risk patients, obtaining complete remission at the end of the induction phase. Four months after the consolidation phase, the patient relapses, and the fourth phase of treatment, maintenance therapy, is required to keep the child in remission.
The treatment of ALL is carried out according to established protocols (4), with the child often having to undergo multiple lumbar punctures for chemotherapy administration and spinal cord aspiration for disease control throughout the disease treatment process (5).
After obtaining parental consent and explanation of the treatment to the child, sites for lumbar puncture and bone marrow aspiration were chosen. The patient was premedicated with midazolam (Dormicum®) 5 mg v.o. and OTFC transmucosal oral fentanyl citrate (Actiq®) 400 mcg v.o., and an EMLA® cream dressing was placed on the puncture sites. Oxygen was administered through nasal goggles at 4 l/m, and the electrocardiogram, capnography, pulse oximetry and blood pressure were monitored from the beginning of the procedure until discharge from the post-anaesthesia recovery unit, according to the recommendations of the Spanish Society of Anaesthesiology and Resuscitation.

After 30 minutes, the skin of the puncture site was infiltrated with 2-5 ml of 1% lidocaine and then treatment was started. On all occasions (4 lumbar punctures and 1 bone aspiration puncture), these could be performed without complications and were well tolerated by the patient. The pain rating according to the Visual Analogue Scale was 2.8 mm (0-10) and according to the verbal categorical scale 1 (0-4). The overall assessment of the efficacy of analgesic treatment was 'good' in all situations, except on the day of lumbar and spinal puncture, which was rated as 'fair'. The parameters monitored during the procedure were within normal limits. There was no nausea, vomiting or pruritus, and the patient was discharged to the ward 60 minutes after the procedure.