The development of a nurse-led preoperative anaesthesia screening tool by Delphi consensus

BACKGROUND

Low- and middle-income countries have a critical shortage of specialist anaesthetists. Most patients arriving for surgery are of low perioperative risk. Without immediate access to preoperative specialist care, an appropriate interim strategy may be to ensure that only high-risk patients are seen preoperatively by a specialist. Matching human resources to the burden of disease with a nurse-administered pre-operative screening tool to identify high-risk patients who might benefit from specialist review prior to the day of surgery may be an effective strategy.

OBJECTIVE

To develop a nurse-administered preoperative anaesthesia screening tool to identify patients who would most likely benefit from a specialist review before the day of surgery, and those patients who could safely be seen by the anaesthetist on the day of surgery. This would ensure adequate time for optimisation of high-risk patients preoperatively and limit avoidable day-of-surgery cancellations.

METHODS

A systematic review was conducted to identify preoperative screening questions for use in a three-round Delphi consensus process. A panel of 16 experienced full-time clinical anaesthetists representing all university-affiliated anaesthesia departments in South Africa participated to define a nurses' screening tool for preoperative assessment.

RESULTS

Ninety-eight studies were identified, which generated 79 questions. An additional 14 items identified by the facilitators were added to create a list of 93 questions for the first round. The final screening tool consisted of 81 questions, of which 37 were deemed critical to identify patients who should be seen by a specialist prior to the day of surgery.

CONCLUSION

A structured nurse-administered preoperative screening tool is proposed to identify high-risk patients who are likely to benefit from a timely preoperative specialist anaesthetist review to avoid cancellation on the day of surgery.

South African cardiovascular risk stratification guideline for non-cardiac surgery

Executive summary The South African (SA) guidelines for cardiac patients for non-cardiac surgery were developed to address the need for cardiac risk assessment and risk stratification for elective non-cardiac surgical patients in SA, and more broadly in Africa.The guidelines were developed by updating the Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Non-cardiac Surgery, with a search of literature from African countries and recent publications. The updated proposed guidelines were then evaluated in a Delphi consensus process by SA anaesthesia and vascular surgical experts. The recommendations in these guidelines are:1. We suggest that elective non-cardiac surgical patients who are 45 years and older with either a history of coronary artery disease, congestive cardiac failure, stroke or transient ischaemic attack, or vascular surgical patients 18 years or older with peripheral vascular disease require further preoperative risk stratification as their predicted 30-day major adverse cardiac event (MACE) risk exceeds 5% (conditional recommendation: moderate-quality evidence).2. We do not recommend routine non-invasive testing for cardiovascular risk stratification prior to elective non-cardiac surgery in adults (strong recommendation: low-to-moderate-quality evidence).3. We recommend that elective non-cardiac surgical patients who are 45 years and older with a history of coronary artery disease, or stroke or transient ischaemic attack, or congestive cardiac failure or vascular surgical patients 18 years or older with peripheral vascular disease should have preoperative natriuretic peptide (NP) screening (strong recommendation: high-quality evidence).4. We recommend daily postoperative troponin measurements for 48 - 72 hours for non-cardiac surgical patients who are 45 years and older with a history of coronary artery disease, or stroke or transient ischaemic attack, or congestive cardiac failure or vascular surgical patients 18 years or older with peripheral vascular disease, i.e. (i) a baseline risk >5% for MACE 30 days after elective surgery (if no preoperative NP screening), or (ii) an elevated B-type natriuretic peptide (BNP)/N-terminal-prohormone B-type natriuretic peptide (NT-proBNP) measurement before elective surgery (defined as BNP >99 pg/mL or a NT-proBNP >300 pg/mL) (conditional recommendation: moderate-quality evidence).Additional recommendations are given for the management of myocardial injury after non-cardiac surgery (MINS) and medications for comorbidities.

Molecular and functional roles of duodenal cytochrome B (Dcytb) in iron metabolism

Dcytb has been identified as the mammalian transplasma ferric reductase that catalyzes the reduction of ferric to ferrous iron in the process of iron absorption. Its mRNA and protein levels are up-regulated by several independent stimulators of iron absorption. Furthermore, its cDNA encodes putative binding sites for heme and ascorbic acid. Using Northern and Western blots, RT-PCR and confocal microscopy, we studied the expression and localisation of Dcytb in cell lines and tissues of CD1 mice. Dcytb expression and function were modulated by iron. Dcytb and DMT1, both predominantly localised in the apical region of the duodenum were up-regulated in iron deficiency. Dcytb, the iron regulated ferric reductase may also utilize cytoplasmic ascorbate as electron donor for transmembrane reduction of iron. Dcytb expression was found in other tissues apart from the duodenum and its regulation and functions at these other sites are of interest in iron metabolism.