High rates of the SDHB p.Arg46Gln pathogenic variant predisposes New Zealand Maori to phaeochromocytoma/paraganglioma.

BACKGROUND: Phaeochromocytomas (PCC) and paragangliomas (PGL; together PPGL) are rare tumours of the adrenal medulla or extra-adrenal paraganglia. They may secrete catecholamines with significant cardiovascular effects. Management of PPGL is predominantly surgical, despite the anaesthetic risks related to potential haemodynamic instability. Meticulous pre-treatment and intra-operative management are required to improve cardiovascular outcomes. AIMS: There are limited local data regarding the incidence of PPGL and the clinical characteristics of individuals diagnosed with these tumours in New Zealand. We undertook a retrospective study investigating the local practice and patient characteristics with an additional focus on intra-operative haemodynamic stability and post-operative outcomes. METHODS: Electronic patient records were searched for individuals with a diagnosis of PPGL. Clinical records and electronic databases were interrogated for pre-operative, intra-operative and post-operative data points. Particular attention was paid to rates and types of germline mutations, intra-operative haemodynamic stability and post-operative renal and cardiovascular outcomes. RESULTS: We identified 49 individuals with PPGL, of whom 34 were from the local area. This gave a local incidence of PPGL of around five cases per million people per year. Maori were significantly over-represented in our cohort, with this being in part due to high rates of the SDHB R46Q mutation. Over 95% of our cohort met pre-specified pre-operative blood pressure parameters. Intra-operative monitoring revealed a tendency to hypotension, but this did not translate into adverse post-operative outcomes, which were infrequent. CONCLUSIONS: Maori were over-represented due to high rates of germline SDHB R46Q mutations. There were few post-operative adverse outcomes in this contemporary cohort.

Anaphylaxis is more common with rocuronium and succinylcholine than with atracurium.

BACKGROUND: Intraoperative anaphylaxis is a rare but serious occurrence, often triggered by neuromuscular-blocking drugs (NMBDs). Previous reports suggest that the rates of anaphylaxis may be greater for rocuronium than for other NMBDs, but imprecise surrogate metrics for new patient exposures to NMBDs complicate interpretation. METHODS: This was a retrospective, observational cohort study of intraoperative anaphylaxis to NMBDs at two hospitals between 2006 and 2012. Expert anesthetic and immunologist collaborators investigated all referred cases of intraoperative anaphylaxis where NMBDs were administered and identified those where a NMBD was considered responsible. New patient exposures for each NMBD were extracted from electronic anesthetic records compiled during the same period. Anaphylaxis rates were calculated for each NMBD using diagnosed anaphylaxis cases as the numerator and the number of new patient exposures as the denominator. RESULTS: Twenty-one patients were diagnosed with anaphylaxis to an NMBD. The incidence of anaphylaxis was 1 in 22,451 new patient exposures for atracurium, 1 in 2,080 for succinylcholine, and 1 in 2,499 for rocuronium (P < 0.001). CONCLUSIONS: In Auckland, the rate of anaphylaxis to succinylcholine and rocuronium is approximately 10-fold higher than to atracurium. Previous estimates of NMBD anaphylaxis rates are potentially confounded by inaccurate proxies of new patient exposures. This is the first study to report anaphylaxis rates using a hard denominator of new patient exposures obtained directly from anesthetic records.

Lead poisoning from Ayurvedic medicines.

A case of lead poisoning with established exposure to Ayurvedic medicines is presented. This patient migrated from India to New Zealand 8 years previously. He regularly visits India where he purchases "herbal remedies" for his wellbeing.

Pulmonary barotrauma and cerebral arterial gas embolism during hyperbaric oxygen therapy.

Hyperbaric oxygen therapy (HBOT) is used to treat a variety of disorders. It is a safe treatment modality, but rare catastrophic complications may occur. In this case report, we describe the occurrence of irreversible spastic quadriparesis in a patient who suffered a cerebral arterial gas embolism (CAGE) during decompression from HBOT. The patient had a history of respiratory disease and was subsequently found to have bullous changes in the left lung, which almost certainly predisposed to this rare event. We discuss appropriate pretreatment screening to prevent such events and highlight the paradox that HBOT, the cause of the CAGE, is also the treatment of choice.

The incidence of hypoxemia during surgery: evidence from two institutions.

PURPOSE: The incidence of hypoxemia in patients undergoing surgery is largely unknown and may have a clinical impact. The objective of this study was to determine the incidence of intraoperative hypoxemia in a large surgical population. METHODS: We performed a retrospective study of electronically recorded pulse oximetry data obtained from two large academic medical centres. All adults (age ≥ 16 yr) undergoing non-cardiac surgery during a three-year period at the two hospitals were included in the analysis. Our main outcome measure was the percentage of patients with episodes of hypoxemia (SpO(2) < 90) or severe hypoxemia (SpO(2) ≤ 85) for two minutes or longer during the intraoperative period (induction of anesthesia, surgery, and emergence). RESULTS: We evaluated 95,407 electronic anesthesia records at the two hospitals. During the intraoperative period, 6.8% of patients had a hypoxemic event, and 3.5% of patients had a severely hypoxemic event of two consecutive minutes or longer. Seventy percent of the hypoxemic episodes occurred during either induction or emergence- time periods that represent 21% of the total intraoperative time. From induction to emergence, one episode of hypoxemia occurred every 28.9 hr, and one episode of severe hypoxemia occurred every 55.7 hr of intraoperative time. CONCLUSION: Despite advances in monitoring technology, hypoxemia continues to occur commonly in the operating room and may be a serious safety concern because of its potential impact on end organ function and long-term outcomes. Further studies are needed to improve our understanding of the clinical impact of intraoperative hypoxemia and the strategies that will be most useful in minimizing its occurrence.

Lax sphygmomanometer standard causes overdetection and underdetection of hypertension: a computer simulation study.

OBJECTIVE: To quantify overdetection and underdetection of hypertension caused by systematic sphygmomanometer errors permitted by the current European standard (EN 1060 'noninvasive sphygmomanometers'). METHODS: We carried out Monte Carlo simulation of measurement of blood pressure (BP) of the adult Australian population using sphygmomanometers showing systematic errors compliant with the EN 1060 standard. We repeated the simulations limiting systematic sphygmomanometer errors to +/-1 mmHg. Simulated BP measurements included systematic sphygmomanometer error, random intraindividual BP variability and random measurement error. RESULTS: After three visits, underdetection of hypertension is common owing to variability of BP measurements and systematic errors of sphygmomanometers. After three visits, the wide tolerances of EN 1060 are responsible for approximately 4.9 and 11% of underdetection of systolic and diastolic hypertension, respectively. Underdetection is worse in some groups, for example, permitted sphygmomanometer error causes 20% of all undetected systolic hypertension in 18-24 year-old women. The current standard also results in overdetection of hypertension. Permitted sphygmomanometer error causes 5.8 and 14% of the overdetection of systolic and diastolic hypertension, respectively, after three visits. Overdetection is worse in some groups, for example, after three visits, permitted sphygmomanometer error causes 19% of falsely detected diastolic hypertension in 18-24 year-old men. For all adults, reduction of permitted sphygmomanometer error to +/-1 mmHg achieves approximately the same improvement in hypertension detection as at least one additional visit to the clinician. CONCLUSION: Systematic sphygmomanometer errors permitted by the current standard are a preventable cause of clinically significant overdetection and underdetection of hypertension. The standard should be revised to make the effects of equipment related systematic errors negligible compared with the effects of physiological variability.