Malignant hyperthermia 2020: Guideline from the Association of Anaesthetists.

Malignant hyperthermia is defined in the International Classification of Diseases as a progressive life-threatening hyperthermic reaction occurring during general anaesthesia. Malignant hyperthermia has an underlying genetic basis, and genetically susceptible individuals are at risk of developing malignant hyperthermia if they are exposed to any of the potent inhalational anaesthetics or suxamethonium. It can also be described as a malignant hypermetabolic syndrome. There are no specific clinical features of malignant hyperthermia and the condition may prove fatal unless it is recognised in its early stages and treatment is promptly and aggressively implemented. The Association of Anaesthetists has previously produced crisis management guidelines intended to be displayed in all anaesthetic rooms as an aide memoire should a malignant hyperthermia reaction occur. The last iteration was produced in 2011 and since then there have been some developments requiring an update. In these guidelines we will provide background information that has been used in updating the crisis management recommendations but will also provide more detailed guidance on the clinical diagnosis of malignant hyperthermia. The scope of these guidelines is extended to include practical guidance for anaesthetists dealing with a case of suspected malignant hyperthermia once the acute reaction has been reversed. This includes information on care and monitoring during and after the event; appropriate equipment and resuscitative measures within the operating theatre and ICU; the importance of communication and teamwork; guidance on counselling of the patient and their family; and how to make a referral of the patient for confirmation of the diagnosis. We also review which patients presenting for surgery may be at increased risk of developing malignant hyperthermia under anaesthesia and what precautions should be taken during the peri-operative management of the patients.

Achondroplasia: anaesthetic challenges for caesarean section.

Pregnancy in women with achondroplasia presents major challenges for anaesthetists and obstetricians. We report the case of a woman with achondroplasia who underwent general anaesthesia for an elective caesarean section. She was 99cm in height and her condition was further complicated by severe kyphoscoliosis and previous back surgery. She was reviewed in the first trimester at the anaesthetic high-risk clinic. A multidisciplinary team was convened to plan her peripartum care. Because of increasing dyspnoea caesarean section was performed at 32weeks of gestation. She received a general anaesthetic using a modified rapid-sequence technique with remifentanil and rocuronium. The intraoperative period was complicated by desaturation and high airway pressures. The woman's postoperative care was complicated by respiratory compromise requiring high dependency care.

The introduction of a surgical safety checklist in a tertiary referral obstetric centre.

BACKGROUND Surgery-related adverse events remain a significant and often under-reported problem. In a recent study, the introduction of a perioperative checklist by the WHO reduced deaths and complications by 46% and 36% respectively. The authors wished to evaluate the introduction of a surgical safety checklist in a busy obstetric tertiary referral centre by assessing staff attitudes, checklist compliance and effects upon patients. METHODS A questionnaire-based assessment was performed on staff working in obstetric theatres before and after the introduction of the surgical safety checklist. Checklist compliance was assessed at 3 months and 1 year. Patients were asked questions relating to the performance of the surgical safety checklist in order to evaluate any anxiety caused. RESULTS Non-medical staff were significantly more likely than medical staff to feel familiar with other team members both before (p<0.001) and after (p=0.03) the introduction of the checklist. 69.6% of all staff felt that interprofessional communication had improved following the introduction of the checklist. Compliance with pre- and postoperative checks was 61.2% and 67.6%, respectively, improving to 79.7% and 84.7% after 1 year. Although the majority of patients were aware of the checks being performed, this did not provoke anxiety. CONCLUSION Following consultation with staff and patients, the authors managed to institute and sustain the performance of a surgical safety checklist for elective cases in obstetric theatres. While significant progress has been made, the authors recognise that further work is required in order to further evaluate and optimise this process.

Patient controlled administration of intravenous alfentanil during elective caesarean section under subarachnoid anaesthesia.

In this observational study, an alfentanil-containing patient controlled analgesia device was evaluated for the relief of visceral pain during elective caesarean section under subarachnoid anaesthesia. Forty healthy women at term received 2.5 mL of intrathecal hyperbaric 0.5% bupivacaine in the sitting position. Surgery began when loss of cold appreciation to the fourth thoracic dermatome was demonstrated. The patient controlled analgesia device was configured to deliver 3 microg.kg(-1) of alfentanil when first actuated. Each subsequent demand delivered 1.5 microg.kg(-1) with a 2-min lock-out interval. Sixty-five percent of women used alfentanil during surgery. The median (IQR) consumption of alfentanil was 360 (278-720) microg. Patient controlled analgesia is a useful method of supplementing subarachnoid anaesthesia for caesarean section. The technique is simple to use and in this group there were no troublesome side effects.

Combined spinal-extradural anaesthesia for preterm and term caesarean section: is there a difference in local anaesthetic requirements?

In a non-blinded observational study, we have tested the null hypothesis that there is no difference in local anaesthetic requirements for subarachnoid anaesthesia between women presenting for Caesarean section at term or preterm (38-42 and 28-35 weeks' gestation, respectively). Using a combined spinal-extradural technique, 2.25 ml of 0.5% hyperbaric bupivacaine was given, in the sitting position, to 50 women presenting for Caesarean section. In 21 of 25 preterm women, adequate sensory block for surgery did not develop (P < 0.001) and they required supplementary extradural local anaesthetic (median 8 ml of 2% lignocaine with 1:200,000 adrenaline (interquartile range 4-12 ml)); preterm women not requiring extradural supplementation were at the upper end of the gestational range. There was a strong linear correlation between increasing gestation and block height in the preterm group (Spearman rank correlation coefficient = 0.74; 95% confidence intervals 0.49, 0.88). All women in the term group developed adequate anaesthesia with the subarachnoid dose alone. Onset of anaesthesia was slower in the preterm group (median 15 vs 5 min) with a lower incidence of hypotension (P = 0.0005).

Metastatic pain in the parturient: treatment with patient-controlled epidural sufentanil.

A 30-year-old primigravid woman presented at 28 weeks gestation with severe pain related to metastatic gastric carcinoma. Pain control was achieved with epidural sufentanil, administered via a patient-controlled analgesia pump, for 5 days, prior to caesarean delivery. Considerations in deciding the optimal therapeutic regime are discussed.

Effect of the preoperative administration of water on gastric volume and pH.

Since the preoperative administration of water might promote gastric emptying and dilute the remaining gastric contents, 50 patients were investigated before elective surgery. One group was given water 100 ml 2 h before operation; the other group was fasted as usual. Volume and pH of gastric contents were measured immediately after the induction of anaesthesia. Although the mean gastric residue was less in those patients who were given water, the differences were not statistically significant. There was no difference in gastric pH between the two groups.