The case for radical pathway re-design before surgery is in part driven by healthcare system pressures which are in turn the result of continuously rising demand in the face of tightly constrained resources. Such circumstances tend to drive revolutionary, rather than incremental, change. The current approach to preoperative assessment, that typically occurs in the weeks leading up to surgery, but is all too often only a few days before surgery, results in a lost opportunity for perioperative physicians to improve patient care. Re-engineering this process based on a patient-focused, pathway-driven vision of perioperative medicine offers a means of exploiting this opportunity. This review explores drivers for change, the opportunity offered by pathway re-design, and suggests a variety of strategies to add value in the preoperative pathway, each of which is facilitated by early engagement between perioperative physician and patient: collaborative decision-making, collaborative behavioural change, targeted comorbidity management as well as expectation management and psychological preparation for surgery including surgery schools.

In practice, clinicians generally consider anemia (circulating hemoglobin concentration < 120 g.l-1 in non-pregnant females and < 130 g.l-1 in males) as due to impaired hemoglobin synthesis or increased erythrocyte loss or destruction. Rarely is a rise in plasma volume relative to circulating total hemoglobin mass considered as a cause. But does this matter? We explored this issue in patients, using the optimized carbon-monoxide rebreathing method to measure hemoglobin concentration and thereby calculate plasma volume in healthy volunteers, surgical patients, and those with inflammatory bowel disease, chronic liver disease or heart failure. We studied 109 participants. Hemoglobin mass correlated well with its concentration in the healthy, surgical and inflammatory bowel disease groups (r= 0.687-0.871, p< 0.001). However, they were poorly related in liver disease (r= 0.410, p= 0.11) and heart failure patients (r= 0.312, p= 0.16). Here, hemoglobin mass explained little of the variance in its concentration (adjusted R2= 0.109 and 0.052; p= 0.11 and 0.16), whilst plasma volume did (R2 change 0.724 and 0.805 in heart and liver disease respectively, p<0.0001). Exemplar patients with identical (normal or raised) total hemoglobin masses were diagnosed as profoundly anemic (or not) depending on differences in plasma volume that had not been measured or even considered as a cause. The traditional inference that anemia generally reflects hemoglobin deficiency may be misleading, potentially resulting in inappropriate tests and therapeutic interventions to address ‘hemoglobin deficiency not plasma volume excess. Measurement of total hemoglobin mass and plasma volume is now simple, cheap and safe, and its more routine use advocated.

Cardiopulmonary exercise testing (CPET) is an exercise stress test with concomitant expired gas analysis that provides an objective, non-invasive measure of functional capacity under stress. CPET-derived variables predict postoperative morbidity and mortality after major abdominal and thoracic surgery. Two previous surveys have reported increasing utilisation of CPET preoperatively in England. We aimed to evaluate current CPET practice in the UK, to identify who performs CPET, how it is performed, how the data generated are used and the funding models. All anaesthetic departments in trusts with adult elective surgery in the UK were contacted by telephone to obtain contacts for their pre-assessment and CPET service leads. An online survey was sent to all leads between November 2016 and March 2017. The response rate to the online survey was 73.1% (144/197) with 68.1% (98/144) reporting an established clinical service and 3.5% (5/144) setting up a service. Approximately 30,000 tests are performed a year with 93.0% (80/86) using cycle ergometry. Colorectal surgical patients are the most frequently tested (89.5%, 77/86). The majority of tests are performed and interpreted by anaesthetists. There is variability in the methods of interpretation and reporting of CPET and limited external validation of results. This survey has identified the continued expansion of perioperative CPET services in the UK which have doubled since 2011. The vast majority of CPET tests are performed and reported by anaesthetists. It has highlighted variation in practice and a lack of standardised reporting implying a need for practice guidelines and standardised training to ensure high-quality data to inform perioperative decision making.

Background. Cardiopulmonary exercise testing (CPET) measures peak exertional oxygen consumption ($V˙O2peak$) and that at the anaerobic threshold ($V˙O2$ at AT, i.e. the point at which anaerobic metabolism contributes substantially to overall metabolism). Lower values are associated with excess postoperative morbidity and mortality. A reduced haemoglobin concentration ([Hb]) results from a reduction in total haemoglobin mass (tHb-mass) or an increase in plasma volume. Thus, tHb-mass might be a more useful measure of oxygen-carrying capacity and might correlate better with CPET-derived fitness measures in preoperative patients than does circulating [Hb]. Methods. Before major elective surgery, CPET was performed, and both tHb-mass (optimized carbon monoxide rebreathing method) and circulating [Hb] were determined. Results. In 42 patients (83% male), [Hb] was unrelated to $V˙O2$ at AT and $V˙O2peak$ (r=0.02, P=0.89 and r=0.04, P=0.80, respectively) and explained none of the variance in either measure. In contrast, tHb-mass was related to both (r=0.661, P<0.0001 and r=0.483, P=0.001 for $V˙O2$ at AT and $V˙O2peak$, respectively). The tHb-mass explained 44% of variance in $V˙O2$ at AT (P<0.0001) and 23% in $V˙O2peak$ (P=0.001). Conclusions. In contrast to [Hb], tHb-mass is an important determinant of physical fitness before major elective surgery. Further studies should determine whether low tHb-mass is predictive of poor outcome and whether targeted increases in tHb-mass might thus improve outcome.

Haemoglobin is the blood’s oxygen carrying pigment and is encapsulated in red blood corpuscles. The concentration of haemoglobin in blood is dependent on both its total mass in the circulation (tHb-mass) and the total plasma volume in which it is suspended. Aerobic capacity is defined as the maximum amount of oxygen that can be consumed by the body per unit time and is one measure of physical fitness. Observations in athletes who have undergone blood doping or manipulation have revealed a closer relationship between physical fitness (aerobic capacity) and total haemoglobin mass (tHb-mass) than with haemoglobin concentration ([Hb]). Anaemia is defined by the World Health Organisation (WHO) as a haemoglobin concentration of <130 g/L for men and <120 g/L for women. Perioperative anaemia is a common problem and is associated with increased mortality and morbidity following surgery. Aerobic capacity is also associated with outcome following major surgery, with less fit patients having a higher incidence of mortality and morbidity after surgery. Taken together, these observations suggest that targeted preoperative elevation of tHb-mass may raise aerobic capacity both directly and indirectly (by augmenting preoperative exercise initiatives- ‘prehabilitation’) and thus improve postoperative outcome. This notion in turn raises a number of questions. Which measure ([Hb] or tHb-mass) has the most value for the description of oxygen carrying capacity? Which measure has the most utility for targeting therapies to manipulate haemoglobin levels? Do the newer agents being used for blood manipulation (to increase tHb-mass) in elite sport have utility in the clinical environment? This review explores the literature relating to blood manipulation in elite sport as well as the relationship between perioperative anaemia, physical fitness and outcome following surgery, and suggests some avenues for exploring this area further.

Introduction. Overdose with the calcium channel blocker amlodipine can cause profound hypotension that may be exacerbated by the concurrent ingestion of an angiotensin II receptor antagonist. Best management of such overdoses is uncertain although the use of hyperinsulinaemia-euglycaemia (HIE) has been recommended.Case report. We report a case of mixed amlodipine and losartan overdose in a 50-year-old lady. Severe hypotension was resistant to conventional vasopressors and high-dose insulin/euglycaemia, but did respond to a metaraminol infusion.Conclusion. A trial of metaraminol early in severe cases of calcium channel blocker and angiotensin II receptor antagonist toxicity may be of benefit, especially when conventional ionotropic treatment measures are failing.