Nonexcitable muscle membrane predicts intensive care unit-acquired paresis in mechanically ventilated, sedated patients*

Abstract

: Abnormal dmCMAP occurred within the first week after admission to the ICU and pointed towards a myopathic process as the primary cause of ICU-acquired paresis. Validation of dmCMAP with onset of critical illness allows an early prediction of ICU-acquired paresis and adds important information to clinical estimation of the patients' motor function.

Validation of the peroneal nerve test to diagnose critical illness polyneuropathy and myopathy in the intensive care unit: the multicentre Italian CRIMYNE-2 diagnostic accuracy study

“…It is therefore not surprising that this patient group also had a high incidence of ICUacquired neuromuscular disorders that are currently viewed not as isolated events, but rather as an integral part of the process leading to MOF 1 . In two recent studies, severe muscle weakness was documented in 74% of patients 38 and electrophysiological abnormalities in 87% 11 . In an unselected population of critically ill children, the occurrence of generalised muscle weakness was substantially lower (1.7%) 39 , reflecting the need for future studies to include much larger samples of unselected ICU patients to evaluate the true incidence of ICU-acquired neuromuscular disorders.…”

“…In the CRIMYNE study 10 , we used the same index test and reference diagnostic standard of the CRIMYNE-2 study, but comparison was unblinded and was limited to patients with abnormal findings at the index test, which may have inflated the test sensitivity. In a prospective observational study in surgical ICU patients 11 , the sensitivity and specificity of dmCMAP in predicting the development of ICU-acquired weakness were 83.3% and 88.8%, respectively. In a more recent study 33 , sensitivity and specificity of combined peroneal nerve CMAP and sural nerve SNAP evaluations were 100% and 81%, respectively.…”

“…PENT is not dependent upon patients' collaboration and could be performed at an early stage to detect initial functional derangement and to use the results to start investigational treatments with the aim of interrupting pathological mechanisms at their onset 43 . Several studies have demonstrated that electrophysiological alterations are followed by muscle weakness, but they included a small number of selected ICU patients [7][8][9][10][11] . PENT is a quick test and could be used in large ICU populations.…”

“…Moreover, NCS may also be useful to predict hospital mortality 9 , and short 13 and long-term morbidity 8,14,15 . CMAP after direct muscle stimulation (dmCMAP) may precede the development of ICU-acquired weakness by several days 11 . Therefore there is a need for a rapid, simple, accurate and valid electrophysiological test to identify CIP and CIM early in ICU.…”

“…In comatose patients or in those with persisting sedation or septic encephalopathy who develop severe muscle weakness or paralysis after ICU admission, electrophysiological investigations can be performed to avoid unreasonably pessimistic prognosis by identification of CIP or CIM as the cause 7 . Electrophysiological alterations are not only essential to establish the diagnosis of CIP and CIM, but they also have an earlier onset than clinical signs or they can be documented at an earlier stage [7][8][9][10][11] , thus offering the advantage of a timely diagnosis and the opportunity to conduct potentially valuable interventions before structural muscle-nerve alterations become established 4 . CMAP reduction is an early event which precedes clinical signs: its onset can be abrupt within 24 hours of normal findings 10 , and it can be observed as early as 48 hours before clinical signs in patients with sepsis 12 .…”