Clinical Features of Suspected Malignant Hyperthermia in China from 2015 to 2020: A Retrospective Study from China Malignant Hyperthermia Emergency Assistance Group

Figures & data

Table 1 Characteristics of Suspected MH Patients in China (n = 36)

Patient Characteristics	Number	Proportion
Age (years)
<3	4	11.1%
3–17	9	25.0%
18–65	21	58.3%
>65	2	5.6%
Sex
Male	32	88.9%
Female	4	11.1%
Hospital grade
Tertiary class-A hospital	30	83.3%
Tertiary class-B hospital	2	5.5%
Second class-A hospital	2	5.5%
Others	2	5.5%

Figure 1 Occurrence year of 58 suspected MH cases.

Table 2 Onset Stage and Anesthetics of 36 Suspected MH Cases

Onset Stage	Inhalation Anesthetic	Intravenous Anesthetic
Induction (n=1)	Sevoflurane (n=1)	Propofol (n=1)
Intraoperative (n=34)	Sevoflurane (n=32)	Propofol (n=32)
	Isoflurane (n=1)	Etomidate (n=1)
	Desflurane (n=1)	Ketamine (n=1)
Postoperative (n=1)	Sevoflurane (n=1)	Propofol (n=1)

Figure 2 Surgery types of 36 suspected MH cases.

Table 3 Clinical Signs of Suspected MH Cases (n = 36)

Early Clinical Signs	Frequency (Proportion)
EtCO2>55 mmHg	36 (100.0%)
Abnormal hyperthermia (>40°C)	30 (83.0%)
Muscular rigidity	18 (50.0%)
Tachycardia or arrhythmia	19 (52.8%)
Advanced clinical signs
Severe acidosis (PH<7.2)	24 (66.7%)
Hyperkalemia (K+> 6 mmol/L)	31 (86.1%)
Rhabdomyolysis (CK>2000 U/L)	23 (63.9%)
Acute renal failure	11 (30.6%)
DIC	11(30.6%)
Circulatory failure	23 (63.9%)
Acute heart failure	1 (2.8%)
Hypocytosis	1 (2.8%)

Abbreviations: EtCO2, end tidal CO2; CK, creatine kinase DIC, disseminated intravascular coagulation.

Table 4 Analyses of RYR1 and CACNA1S Variants Reported in 4 Patients

Patient	Gene	Nucleotide Change	Amino Acid Change	ClinVar^§ Public Archive
Case 1	RYR1	c.7361G>A	p.Arg2454His	Pathogenic
Case 2	RYR1	c.5317C>T	p.Pro1773Ser	Benign
		c.12587T>C	p.Ile4196Thr	ND
	CACNA1S	c.5399T>C	p.Leu1800Ser	Benign
Case 3	RYR1	c.14512C>G	p.Leu4838Val	Pathogenic
Case 4	RYR1	c.5194G>A	p.Glu1732Lys	ND

Note: ^§ClinVar=ClinVar is a public archive of interpretations of clinically relevant variants (https://www.ncbi.nlm.nih.gov/clinvar/).

Abbreviation: ND, not determined.

Figure 3 The association between administration time of dantrolene and outcomes. The increased time interval between the first signs of MH and dantrolene administration is associated with increased mortality (p = 0.071).