Totally 110 articles and 92 cases were used from the most commonly used databases in China. Exclusion criteria were dubious MH episodes only caused by Ketamine administration or MH episodes irrelevant to anesthesia. This study may be limited by incomplete patient data and underreporting, but analysis bias seems to be minimal because there were no significant differences between comparisons of survived and death cases.
For the incident departments, they were concentrated in departments of orthopedics, stomatology, and hepatobiliary surgery. Around half of the incident years focused on 2001-2010. The male to female of MH cases was 3.5:1. More than half of MH cases focused on the 7-18 and 19-40 demographic. In all these MH cases reported, the total mortality was 42 (45.7%), less than the mortality rate 64%-70% reported before administration of dantrolene [9, 10]. Even in the absence of dantrolene, the mortality was down to 36.0% from 2011 to 2020. In terms of anesthetics, more than half of all these cases were administered volatile anesthetic without succinylcholine, mainly including isoflurane, sevoflurane, and enflurane. Besides, the most frequent initial signs of these cases were hypercarbia, sinus tachycardia, hyperthermia, and masseter spasm.
Although there were no significant differences between comparisons of survived and death cases, some clues were still found from the analysis. From the comparisons, the death cases had higher maximum end-tidal PCO2, maximum arterial PCO2, temperature first measured when the patient was first discovered abnormal, maximum temperature and potassium, and had more serious metabolic acidosis and more possibility of coagulation disorders. On the treatment side, cases that used furosemide, mannitol, blood purification treatment had a significant advantage on the outcome, which showed renoprotective therapies play important roles in outcomes in these MH cases.
The 13 cases with more enzyme data were all at MH rank 6. But there were wide differences in concentration of CPK, myoglobin, and CPK-MB between these `almost certain` cases. Therefore, the low size of these enzyme value might be that they can’t be used to rule out MH episode or determine the severity of MH, which confirm the study made by Carpenter et al.[122] that different RYR1 variants vary in the severity of CPK concentration. Besides, most of the cases’ pick time was on the second day, while occasional cases were on the third, fifth, or sixth day.
Almost half of these MH cases had congenital diseases. Around one in eight of the cases had abnormal enzyme results and mildly elevated body temperature. Therefore, anesthesiologists should take precautions when there are congenital diseases, these abnormal enzyme results or abnormally elevated body temperature for unexplained reason in pre-anesthesia patients and need to avoid administering volatile anesthetics and depolarizing neuromuscular blocking drugs muscle relaxants and strengthen monitoring in the susceptible individuals.
MH is inherited as an autosomal dominant disorder. Seven members of the immediate family of one patient all took the genetic testing, and except for the patient’s father the other six members all tested positive and have MH susceptibility. Therefore, once MH episode happens, all family members later need to be advised to take genetic testing, and if the test is positive they are further advised to make warning cards, bracelets, or necklaces with MH susceptible on them and carry them at all times to alert anesthesiologist, nurse anesthetists, and relevant staffs in case they need anesthesia in the future.
MH is a rare but life-threatening disorder. When body temperature is over 41 °C, disseminated intravascular coagulation (DIC) is the most common cause of death [1]. The possibility of any complication almost triples per two degrees Celsius rise in maximum body temperature [123]. The lack of dantrolene is the main limitation of MH treatment. Therefore, early warning and diagnosis and prompt effective therapies are crucial for MH patients to survive, especially in the countries that dantrolene is not readily available. There is a pressing need to establish an MH website and a telephone hotline available around the clock in China and countries that have not had these yet, and anesthesiologists, nurse anesthetists, and relevant staff are also urged to register MH episodes by real-name or anonymity. All information can be collected through the internet and directly uploaded to the national database in real-time. With the consent of those MH susceptible people, the identity information is uploaded. And the information can only be disclosed in internal systems among hospitals and related units. Once these people need to undergo anesthesia, anesthesiologists, nurse anesthetists, and relevant staff can receive alerts immediately. Besides, the need to carry out extensive publicity and education concerning MH incidence, clinical presentation, pathophysiology, diagnosis, and treatment is also urgent, not only on professionals and also ordinary people. Let as many people as possible realize the importance and seriousness. MH susceptible persons would volunteer to upload their identity information by themselves.
In conclusion, in countries that dantrolene is not readily available, early warning, diagnosis, and prompt effective therapies are crucial for MH patients to survive.