Use of the cumulative sum method (CUSUM) to assess the learning curves of ultrasound-guided continuous femoral nerve block

BACKGROUND

Although ultrasound is a basic competence for anaesthesia residents (AR) there is few data available on the learning process. This prospective observational study aims to assess the learning process of ultrasound-guided continuous femoral nerve block and to determine the number of procedures that a resident would need to perform in order to reach proficiency using the cumulative sum (CUSUM) method.

METHODS

We recruited 19 AR without previous experience. Learning curves were constructed using the CUSUM method for ultrasound-guided continuous femoral nerve block considering 2 success criteria: a decrease of pain score>2 in a [0-10] scale after 15minutes, and time required to perform it.

RESULTS

We analyse data from 17 AR for a total of 237 ultrasound-guided continuous femoral nerve blocks. 8/17 AR became proficient for pain relief, however all the AR who did more than 12 blocks (8/8) became proficient. As for time of performance 5/17 of AR achieved the objective of 12minutes, however all the AR who did more than 20 blocks (4/4) achieved it.

CONCLUSIONS

The number of procedures needed to achieve proficiency seems to be 12, however it takes more procedures to reduce performance time. The CUSUM methodology could be useful in training programs to allow early interventions in case of repeated failures, and develop competence-based curriculum.

Clinical protocol for the management of malignant hyperthermia

Malignant hyperthermia is a hypermetabolic syndrome that appears in susceptible patients after exposure to certain anaesthetic drugs (succinylcholine, inhalation anaesthetics). Its incidence in Spain is 1 in 40,000 adults, with a 10% mortality rate. It is induced by an abnormal regulation of the ryanodine receptors, producing a massive release of calcium from the sarcoplasmic reticulum in the striate muscle. Clinical manifestations include: CO₂ increase, tachycardia, haemodynamic instability, metabolic and respiratory acidosis, profuse sweating, hyperpyrexia, CPK increase, myoglobinuria, kidney failure, disseminated intravascular coagulation (DIC), and ending in cardiac arrest. Dantrolene sodium is a ryanodine receptor antagonist, and inhibits the release of intracellular calcium. Definitive diagnosis is achieved by the exposure of muscle fibres to caffeine and halothane. Protocols can help guarantee a reliable and secure management when this severe event occurs.

Ventilation with facial mask in the prone position for radiotherapy procedures in children

OBJECTIVES

Ventilation of patients undergoing procedures in the prone position represents a challenge for the anesthesiologist, especially when trying to avoid tracheal intubation. This study aimed to test the effectiveness and safety of a prototype designed for pediatric facial mask ventilation in the prone position.

MATERIAL AND METHODS

A prospective descriptive study was conducted on 105 sedations performed in 3 children scheduled for radiotherapy treatment of posterior fossa desmoplastic medulloblastoma (6 and 4 y.o. males), and neuroblastoma in temporal area (4 y.o. male). Induction and maintenance of sedation were conducted with sevoflurane in oxygen, maintaining spontaneous ventilation. After achieving loss of consciousness and immobility, the patients were placed in the prone position. Their heads were fixed with the forehead and face supported by a prototype made with a cast of expanded polystyrene (EPS), which held the facial mask (connected to a Mapleson D circuit), and the back of the head immobilized with a layer of thermoplastic material. Time variables and complications were recorded.

RESULTS

All sedations were performed according to the planned protocol. All patients maintained oxygen saturation levels above 95%, and no complications were reported. Daily hospital length of stay including the procedure and post anesthetic recovery was 54.4±7.9 min (mean±SD).

CONCLUSIONS

The prototype and the sedation technique with face mask in the prone position employed were effective and safe, allowing the completion of the radiotherapy sessions and securing the airway in a minimally invasive way, maintaining adequate ventilation, light sedation and enabling early hospital discharge.