Diaphragmatic thickness ratio (inspiratory/expiratory) as a diagnostic method of diaphragmatic palsy associated with interescalene block

INTRODUCTION

Diaphragmatic paralysis is a side-effect associated with interscalene block. Thickness index of the diaphragm muscle (inspiratory thickness/expiratory thickness) obtained by ultrasound has recently been introduced in clinical practice for diagnosis of diaphragm muscle atrophy. Our objective was to evaluate this index for the diagnosis of acute phrenic paresis associated with interscalene block.

PATIENTS AND METHODS

We designed an observational study in 22 patients scheduled for shoulder arthroscopy. Spirometry was performed (criteria of phrenic paresis was a decrease in FVC and FEV1 ≥20%). Ultrasound apposition zone was assessed in anterior axillary line and diaphragmatic displacement was evaluated on inspiration and expiration (number of intercostal spaces; phrenic paresis considered a reduction ≥25%) and thickness of the diaphragm muscle (a phrenic paresis was considered an index <1.2). These determinations were performed before and at 20min after interscalene block at C5-C6 with 20ml of 0.5% ropivacaine.

RESULTS

Twenty-one patients (95%) presented phrenic nerve block according to one or more of the methods used. One patient did not show any symptoms or signs suggestive of phrenic paralysis and was excluded. All the patients presented phrenic paresis based on the diaphragmatic thickness index, with the pre-block index being 1.8±0.5 and post-block of 1.05±0.06 (P<0.001). Ninety percent of the patients (19) presented phrenic paresis according to spirometry and all the patients had a reduction in diaphragmatic movement after the block (from 1.9±0.5 intercostal spaces to 0.5±0.3; P<0.001).

CONCLUSION

The index of inspiratory / expiratory diaphragmatic thickness at cut-off <1.2 seems to be useful in the diagnosis of phrenic paresis associated with interscalene block. This index does not require a baseline pre-assessment.

[SECOT consensus on thromboembolisms in knee and hip replacement surgery]

The purpose of this paper is to develop a professional consensus that proposes, in the light of the current scientific evidence and the clinical experience of an expert panel, some clinical recommendations directed at the Orthopaedic and Trauma Surgery (OTS) specialist and with the aim of reducing the variability in the prophylactic management of venous thromboembolic disease in knee and hip arthroplasty in clinical practice. The Delphi method was used, which consisted of two rounds of an e-mail questionnaire. Of the 55 items considered, a consensus was reached in 37 (67.2%) of them. In 31 cases there was consensus with the formulation of the item, and in 6 cases there was no agreed consensus. It was observed that there was a consensus in multiple clinical recommendations that could help OTS specialists in the making of decisions in their clinical practice.