Associations between preoperative anaemia and hospital costs following major abdominal surgery: cohort study.

BACKGROUND: Determining the cost-effectiveness and sustainability of patient blood management programmes relies on quantifying the economic burden of preoperative anaemia. This retrospective cohort study aimed to evaluate the hospital costs attributable to preoperative anaemia in patients undergoing major abdominal surgery. METHODS: Patients who underwent major abdominal surgery between 2010 and 2018 were included. The association between preoperative patient haemoglobin (Hb) concentration and hospital costs was evaluated by curve estimation based on the least-square method. The in-hospital cost of index admission was calculated using an activity-based costing methodology. Multivariable regression analysis and propensity score matching were used to estimate the effects of Hb concentration on variables related directly to hospital costs. RESULTS: A total of 1286 patients were included. The median overall cost was US $18 476 (i.q.r.13 784-27 880), and 568 patients (44.2 per cent) had a Hb level below 13.0 g/dl. Patients with a preoperative Hb level below 9.0 g/dl had total hospital costs that were 50.6 (95 per cent c.i. 14.1 to 98.9) per cent higher than those for patients with a preoperative Hb level of 9.0-13.0 g/dl (P < 0.001), 72.5 (30.6 to 128.0) per cent higher than costs for patients with a Hb concentration of 13.1-15.0 g/dl (P < 0.001), and 62.4 (21.8 to 116.7) per cent higher than those for patients with a Hb level greater than 15.0 g/dl (P < 0.001). Multivariable general linear modelling showed that packed red blood cell (PRBC) transfusions were a principal cost driver in patients with a Hb concentration below 9.0 g/dl. CONCLUSION: Patients with the lowest Hb concentration incurred the highest hospital costs, which were strongly associated with increased PRBC transfusions. Costs and possible complications may be decreased by treating preoperative anaemia, particularly more severe anaemia.

Feasibility and acceptability of remotely monitored pedometer-guided physical activity.

Nearly 70% of the Australian adult population are either sedentary, or have low levels of physical activity. There has been interest in addressing this problem by the 'mHealth', or mobile Health, arena, which is concerned with the confluence of mobile technology and health promotion. The newer generation of activity pedometers has the ability to automatically upload information, to enable aggregation and meta-data analysis of individual patient data. We conducted a ten-week pilot trial of the Fitbit Zip® pedometer using a validated tool in ten volunteers, finding it highly acceptable to both participants and investigators. Data synching was ranked as 'very easy' or 'easy' by all participants, and investigators could successfully monitor activity levels remotely. Median (interquartile range) daily step counts of participants over the ten-week trial ranged from 5471 (4591-7026) to 18779 (15031-21505) steps. Sedentary time over the study period ranged from 1.4% to 33.3% of study days. Percentage of days reaching the target activity level of >10,000 steps/day varied markedly between participants from 4.5% to 95.7%. This study demonstrates the feasibility and acceptability of a remotely monitored pedometer-guided physical activity intervention. This technology may be useful to encourage increased exercise as a form of 'prehabilitation' of adequately screened at-risk surgical or obstetric patients.

Changing patterns in volatile anaesthetic agent consumption over seven years in Victorian public hospitals.

Evidence-based choices of volatile agents can increase health cost efficiencies. In this pharmaco-economic study, we evaluated the trends and costs of volatile agent use in Australian public hospitals. The total number of volatile agent (isoflurane, sevoflurane and desflurane) bottles ordered and inflation-adjusted costs were collected from 65 Victorian public hospitals from 2005 to 2011. Environmental costs were measured through the 100-year global warming potential index as carbon dioxide equivalents. During this time period, the aggregate inflation-adjusted expenditure was $39,209,878. Time series analysis showed that bottles of isoflurane ordered decreased by 419/year (99% confidence interval (CI): -603 to -235); costs decreased by $56,017/year (99% CI: -$93,243 to -$18,791). Bottles of sevoflurane increased by 1,330/year (99% CI: 1141 to 1,519); costs decreased by $423,3573/year (99% CI: -$720,030 to -112,783). Bottles of desflurane increased by 726/year (99% CI: 288 to 1,164); costs increased by $171,578/year (99% CI: $136,951 to $206,205). The amount of calculated greenhouse gas emissions released into the atmosphere over this period was 37,000 tonnes of carbon dioxide equivalents, with isoflurane contributing 6%, sevoflurane 17%, and desflurane 77% of this total. In conclusion, isoflurane is no longer being used in the majority of Victorian public hospitals, with sevoflurane and desflurane remaining as the primary volatile agents, utilised respectively at a ratio of 2.2 to 1, and costs at 0.8 to 1.

The microbiological and sustainability effects of washing anaesthesia breathing circuits less frequently.

In the presence of single-use airway filters, we quantified anaesthetic circuit aerobic microbial contamination rates when changed every 24 h, 48 h and 7 days. Microbiological samples were taken from the interior of 305 anaesthetic breathing circuits over a 15-month period (3197 operations). There was no significant difference in the proportion of contaminated circuits when changed every 24 h (57/105 (54%, 95% CI 45-64%)) compared with 48 h (43/100 (43%, 95% CI 33-53%, p = 0.12)) and up to 7 days (46/100 (46%, 95% CI 36-56%, p = 0.26)). Median bacterial counts were not increased at 48 h or 7 days provided circuits were routinely emptied of condensate. Annual savings for one hospital (six operating theatres) were $AU 5219 (£3079, €3654, $US 4846) and a 57% decrease in anaesthesia circuit steriliser loads associated with a yearly saving of 2760 kWh of electricity and 48 000 l of water. Our findings suggest that extended circuit use from 24 h up to 7 days does not significantly increase bacterial contamination, and is associated with labour, energy, water and financial savings.

Perioperative mortality risk score using pre- and postoperative risk factors in older patients.

We developed a risk score for 30-day postoperative mortality: the Perioperative Mortality risk score. We used a derivation cohort from a previous study of surgical patients aged 70 years or more at three large metropolitan teaching hospitals, using the significant risk factors for 30-day mortality from multivariate analysis. We summed the risk score for each of six factors creating an overall Perioperative Mortality score. We included 1012 patients and the 30-day mortality was 6%. The three preoperative factors and risk scores were ("three A's"): 1) age, years: 70 to 79 = 1, 80 to 89 = 3, 90+ = 6; 2) ASA physical status: ASA I or II = 0, ASA III = 3, ASA IV = 6, ASA V = 15; and 3) preoperative albumin < 30 g/l = 2.5. The three postoperative factors and risk scores were ("three I's") 1) unplanned intensive care unit admission = 4.0; 2) systemic inflammation = 3; and 3) acute renal impairment = 2.5. Scores and mortality were: < 5 = 1%, 5 to 9.5 = 7% and > or = 10 = 26%. We also used a preliminary validation cohort of 256 patients from a regional hospital. The area under the receiver operating characteristic curve (C-statistic) for the derivation cohort was 0.80 (95% CI 0.74 to 0.86) similar to the validation C-statistic: 0.79 (95% CI 0.70 to 0.88), P = 0.88. The Hosmer-Lemeshow test (P = 0.35) indicated good calibration in the validation cohort. The Perioperative Mortality score is straightforward and may assist progressive risk assessment and management during the perioperative period. Risk associated with surgical complexity and urgency could be added to this baseline patient factor Perioperative Mortality score.

End-tidal oxygen measurement compared with patient factor assessment for determining preoxygenation time.

Time to adequate preoxygenation was assessed in 200 elective surgical patients, using measurement of end-tidal oxygen concentration. A variety of patient factors were assessed as to their ability to predict the time required to preoxygenate a patient. Of the 200 patients, 23 (11.5%) were unable to be adequately preoxygenated; most of these cases were due to a poor mask fit. The average time for preoxygenation was 154 seconds (range 43-364 seconds). Of those patients who could be preoxygenated, 46 (23%) required more than three minutes. Although a regression equation could be constructed to calculate time required for preoxygenation, the wide standard errors of the coefficients preclude a clinically useful predictive equation. We thus found that we could not accurately predict time required for preoxygenation and that a routine three minutes preoxygenation may not be sufficient for many patients. However, the measurement of end-tidal oxygen concentration is a very useful method of determining the end-point for preoxygenation.