{'fraction_non_alphanumeric': 0.023868722028841372, 'fraction_numerical': 0.012928891098955743, 'mean_word_length': 5.307210031347962, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
This Month in: Anesthesiology.

Will it soon be possible to avoid the invasiveness of the in vitro contracture test (IVCT) to establish diagnosis of malignant hyperthermia (MH) susceptibility? To analyze the applicability of the European Malignant Hyperthermia Group guidelines for genetic testing of MH, Girard et al. recruited 208 patients from 62 different families to undergo diagnostic procedures. Initially, 67 individuals from families with known MH mutations underwent molecular genetic testing (amplification of genomic DNA by polymerase chain reaction and restriction enzyme digestion). Thirty-two of those people (48%) were identified as carrying the familial mutation. In the other 35 individuals, a familial mutation could not be identified. Twenty of those 35 who tested negative were then scheduled for open muscle biopsy with regional anesthesia. The IVCT consisted of two halothane and two caffeine tests performed on separate muscle bundles. Of those undergoing IVCT, 19 were diagnosed as MH-negative and one as MH-equivocal. Fifteen others with negative molecular genetic testing results have not yet undergone open muscle biopsy and IVCT, mostly because of age-related issues, although six of these will be scheduled as testing becomes available. Another 141 individuals underwent IVCT without previous molecular genetic testing. In that group, 23 MH-susceptible, 88 MHnegative, and 30 MH-equivocal individuals were identified. The results of this study demonstrated that MH susceptibility could be reliably confirmed in about 50% of patients with noninvasive genetic testing alone. However, negative results of genetic testing cannot unequivocally rule out MH susceptibility, so IVCT testing must remain a part of the diagnostic routine. Because of this, the authors prefer to discuss and obtain consent for the possibility of open muscle biopsy before genetic testing is initiated. In this way, clinicians may be able to avoid refusals of IVCT in MH-negative patients with genetic testing.