Ultrasound evaluation of diaphragm function and its application in critical patients, mechanical ventilation and brachial plexus block. / Valoración ecográfica de la función diafragmática y sus aplicaciones en el paciente crítico, en ventilación mecánica y en la anestesia del plexo braquial.

Before diaphragm ultrasonography, assessment of diaphragm function was very difficult due to the complex nature of its exploration. The use of this new technique has shed light on diagnostic problems and treatment with an improvement in final outcomes for critically ill patients, in whom the incidence of diaphragm weakness or dysfunction has been underestimated. Better knowledge of diaphragm function enables us earlier diagnosis by quantification of diaphragm contractile activity or evaluation of functional status after delivery of plexus block anaesthesia, facilitating therapeutic decisions. It is also being used as a guide in the process of weaning from mechanical ventilation or as the safest approach for braquial plexus block. In this review we present how to perform a systematic exploration of diaphragm function and its clinical implications.

A Review of the Ultrasound Assessment of Diaphragmatic Function in Clinical Practice.

Ultrasonography is the only non-invasive, non-ionizing imaging technique widely available to directly assess diaphragmatic function. Two different sonographic approaches permit the assessment of muscle thickening in the zone of apposition and excursion of the dome of the diaphragm. Thanks to the new hand-held ultrasound instruments, the morphology and function of the diaphragm can be assessed in different settings, such as outpatient clinic, pulmonary function test laboratory, hospital department and intensive care unit, and under different conditions. Despite the existence of different acoustic views and several codified approaches, a comprehensive sonographic examination has never been standardized for clinical use. In this review, we summarize the clinical indications, methods and perspectives of the technique in adults.

[Ultrasonographic assessment of hemidiaphragm paralysis secondary to interscalene block]. / Evaluación ultrasonográfica de la parálisis hemidiafragmática secundaria a bloqueo interescalénico.

BACKGROUND: In shoulder surgery, interscalene brachial plexus block has an incidence of 100% hemidiaphragm palsy due to phrenic nerve block. Controling the hemidiaphragm becomes a security ventilation parameter. OBJECTIVE: identify and evaluate with ultrasound hemidiaphragm paralysis after interscalene block. METHODS: This prospective study included 50 patients scheduled for shoulder surgery with interscalene block using neurostimulation. Diaphragmatic movement was evaluated by ultrasound prior to placement of block and the end of the surgical procedure to make the comparison between the two measurements. RESULTS: Comparing the duration of the respiratory cycle at the start and the end of the surgical procedure, both normal and forced ventilation, there is a statistically significant difference of p < 0.001, as with the depth of the hemidiaphragm was found p < 0.001. 90% of patients had no adverse events, 8% had Horner's syndrome and 2% periauricular hypoesthesia. Hemidiaphragm paralysis was found in all cases, with a volume of 30 mL local anesthetic. CONCLUSIONS: Ultrasound is a reliable tool that allows real time viewing of the respiratory cycle and measurements of the diaphragm dome it serves to identify diaphragmatic hemiparesis.