Discussion
As health care costs continue to rise in Canada12, more emphasis has been directed towards efficient usage of resources. The first step is to evaluate the current landscape. As physicians, there is an opportunity to address the health care system based on medical necessity, and to look for efficiencies. This study evaluated a large, comprehensive cohort from a single-payer healthcare system, and identified current and historical anesthesia consult utilization.
Individual centres have demonstrated that preoperative anesthesia consultations reduce patient anxiety13, reduce cancellations on the day of surgery14-16, and reduce hospital costs17. It is unclear though whether these same benefits are borne out when applied to a population.
The Canadian Institute for Health Information reports that 15.1% of health care expenditures are paid for physician services18. In addition to the physician costs, there are costs for facility/infrastructure, additional personal (including nurses, receptionists, custodial staff), laboratory testing, and medical imaging. Furthermore, it has been reported that preoperative anesthesia consultations result in higher rates of ordering possibly unnecessary specialized testing, including echocardiography8. It is important to note that echocardiography provides minimal additional prognostic information above clinical risk factors19and additional bloodwork, for example Brain Natriuretic Peptide (BNP)20.
A major concern from a surgical and health systems/resource management standpoint is the possibility of cancellation on the day of surgery. As well, the authors recognize that system and cultural differences exist at different hospitals, and by different physicians, in terms of utilization of these preoperative consultations. This is supported by the present study, which described geographic variability in the usage of preoperative anesthesiology consultations. However, the worry of surgery cancellation may feed, at least in part, increased usage of preoperative anesthesia consultations. It may be possible that through the use of structured medical directives and identification of patients in need of consultation by the hospital’s presurgical screening clinic, some fears can be mitigated. The authors acknowledge that this is a much-needed area of research.
An interesting subgroup identified consisted of patients undergoing preoperative anesthesia consults prior to cataract surgery. Thilen et al.9 found a substantial increase from 1995 to 2006 in preoperative consultation prior to cataract surgery. The current study found that after knee and hip replacement, the third most common operation leading to utilization of preoperative anesthesia consultation was cataract surgery. This may be due in part to older and more medically complex patients being offered cataract surgery than in the past. Also, it may be that additional procedures are being completed at the same time to address glaucoma or other concomitant issues. However, it is also possible that policies and routine approaches in some centres might find efficiencies by re-evaluating the need for such consultations.
It is interesting that the percentage of ASA I and II patients who receive preoperative anesthesia consultations has decreased markedly over time (Figure 4). This may already reflect the strains and limitations being placed on the healthcare system. There is a slight tendency for early and late career surgeons to order more ASA I/II preoperative consults compared to mid-career physicians (Figure 5). At this time, it is not clear why this pattern was observed, however, the findings are consistent with previous research showing a tendency for younger physicians to order more preoperative investigations21. As our system responds to the pressures of increasing numbers and comorbidities of patients, likely many hospitals are already finding efficiencies. Also, the movement towards limiting unnecessary preoperative testing (Choosing Wisely Canada) is likely taking hold. The results of this study provide data to further the discussion surrounding preoperative anesthesia consultations.
There are limitations that are intrinsic to administrative data. There are many good reasons why some ASA I and II patients should undergo preoperative anesthesia consultation that may not appear in the datasets used. For example, patient factors such as features predicting very difficult airway management, language barrier, extreme anxiety surrounding anesthesia or a personal or family history of problematic anesthesia would be good indications for anesthesia consultation. These factors might not be captured by the ASA classification in terms of ASA III or above. Similarly, longer or more complex surgeries requiring management including prone positioning, one-lung ventilation, or the anticipation of significant blood loss or fluid shifts or potential for significant postoperative pain would be reasons for anesthesia consultation in a healthy patient. Having said this, these sorts of surgeries were not in the top five most common procedures captured by this study.
Data quality also relies on initial accurate coding by the physician and hospital coders. A comparison of administrative data with hospital chart data concluded that major events (surgical procedures, mortality, patient demographics, primary diagnoses) are accurately coded22.
An interesting group of patients are those 19.3% who underwent an anesthesia consultation and then did not proceed to surgery within 3 months. There are a few possible explanations for this. First, it may be that after discussion with the anesthesiologist the patient decided not to go ahead with the surgical procedure. This can occur after an individualized explanation of medical risks or postoperative predicted morbidity or mortality based on patient and surgical factors. For example, a medically complex patient may choose not to undergo a hip replacement to avoid a potential postoperative complication. This is a great use of the system and allowed patient autonomy and informed shared decision making. Secondly, it may be that the surgery was postponed outside the 3 month window due to medical or scheduling reasons. This patient would then likely undergo surgery at a later time (after potentially undergoing further pre-operative assessment). This is a reality of our medical system, and offers opportunities to ensure we repeat as little as medically necessary to get the patient ready for the delayed surgery. Finally, after undergoing anesthesia consultation, the patient may not undergo surgery because it is no longer required, or the patient changes his or her mind – unrelated to the anesthesiologist assessment. Further understanding this group of patients could potentially provide some areas for increasing efficiency.
The results demonstrated a doubling of anesthesia consults per year over the course of the study. For a meaningful understanding of this number, the denominator (number of surgeries per year) is needed. The authors acknowledge that this information is not straightforward to obtain in a reliable manner. To the best of our knowledge, the data from Statistics Canada would be the most applicable. Evaluation of Statistics Canada waiting times for non-emergency surgery23 revealed that in Ontario, yearly surgical volumes increased modestly from 544,002 in 2005 to 704,890 in 2013, an increase of 29.6%. The data from the present study indicates a much larger increase for anesthesia consults of 92.9% (from 112,983 to 217,959) over this timeframe (2005-2013). This may be due to many factors, including increased numbers of patient medical comorbidities, increased surgical procedure complexity, surgeon/anesthesiologist/hospital preference, and patient desire for discussion surrounding the anesthetic itself.