Phrenic nerve conduction studies in acute organophosphate poisoning

✍ Scribed by Gagandeep Singh; U.P.S. Sidhu; R. Mahajan; G. Avasthi; J. Whig

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 128 KB
• Volume: 23
• Category: Article
• ISSN: 0148-639X
• DOI: 10.1002/(sici)1097-4598(200004)23:4<627::aid-mus23>3.0.co;2-s

✦ Synopsis

Phrenic nerve conduction studies were performed within 48 h of admission and subsequently in 29 patients (14 of whom required mechanical ventilation) with acute organophosphate (OP) poisoning. The mean (±SD) amplitude of the diaphragmatic compound muscle action potential (CMAP) in patients requiring mechanical ventilation (119.09 ± 173.85 µV) was significantly lower than in those not requiring mechanical ventilation (461.63 ± 138.69 µV) (P < 0.0001). Diaphragmatic CMAP amplitudes in ventilated patients increased with time during the course of hospitalization and were normal in 5 (36%) patients and only mildly reduced in another 6 (43%) patients prior to discontinuation of mechanical ventilation, which was undertaken 4-18 days (mean 7 ± 3 days) after poisoning. Eleven patients (79%) were successfully weaned from mechanical ventilation at the first attempt. In the 3 (21%) remaining patients, mechanical ventilation had to be reestablished because of weaning failure. The mean (±SD) diaphragmatic CMAP amplitude, prior to discontinuation of ventilatory assistance, was 242.6 ± 94.1 µV in these 3 patients. After ventilatory discontinuation, it fell to 95.5 ± 105.8 µV. Thus, reduced diaphragmatic CMAP amplitudes correlate with the need for mechanical ventilation in acute OP poisoning.