Preoperative patient assessment: Identifying patients at high risk

Accepted Manuscript Preoperative Patient Assessment: how to detect the patient at real high risk O. Boehm, G. Baumgarten, A. Hoeft, M.D., Professor

PII:

S1521-6896(16)30006-4

DOI:

10.1016/j.bpa.2016.04.005

Reference:

YBEAN 894

To appear in:

Best Practice & Research Clinical Anaesthesiology

Received Date: 16 March 2016 Revised Date:

19 April 2016

Accepted Date: 27 April 2016

Please cite this article as: Boehm O, Baumgarten G, Hoeft A, Preoperative Patient Assessment: how to detect the patient at real high risk, Best Practice & Research Clinical Anaesthesiology (2016), doi: 10.1016/j.bpa.2016.04.005. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Preoperative Patient Assessment: how to detect the patient at real high risk

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Boehm O1, Baumgarten G1, Hoeft A1

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1 Department of Anesthesiology and Intensive Care, University Clinic Bonn, Germany

Corresponding author:

Head of the department

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Professor Andreas Hoeft, M.D.

Department of Anesthesiology and Intensive Care,

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University Clinic Bonn, Germany Sigmund-Freud-Straße 25

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53105 Bonn

E-Mail: [email protected] Fon: +49 (0)228 287 14110 Fax: +49 (0)228 287 14115

This work has not been funded by any organization.

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Abstract Postoperative mortality remains alarmingly high with a mortality rate ranging between 0.44%. A small sub-group of multimorbid and/or elderly patients undergoing different surgical

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procedures, naturally confers the highest risk for complications and perioperative death. Therefore, preoperative assessment should identify these high risk patients and stratify them to individualized monitoring and treatment throughout all phases of perioperative care. A

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“tailored” perioperative approach might help to further reduce perioperative morbidity and mortality.

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This article aims to elucidate individual morbidity-specific risks. It further suggests

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approaches to detect patients at risk for perioperative complications.

Keywords: preoperative risk assessment, perioperative risk, postoperative mortality, risk

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score, biomarkers

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Highlights •

A small subgroup of high risk patients account for a very high percentage of perioperative mortality. Early and well-structured preoperative risk assessment is recommended for the

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identification of high risk patients using various risk scores and various new biomarkers.

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Individualizing preoperative risk assessment as well as intra- and postoperative reassessment allows for better planning during all stages of the perioperative pathway and

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hence should decrease morbidity and mortality also in the high risk population.

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Introduction Due to many improvements achieved in perioperative care overall mortality has significantly decreased over the last decades. However, there still remains an unsatisfyingly high

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proportion of patients, which suffer from permanent damage or die after an operation with evidence suggesting an overall postoperative mortality of 0.4-4% [28, 49].The highest mortality is observed only in a smaller proportion of patients, which either are suffering from

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preexisting- morbidity or are subjected to major surgery or both.

Hence, effective preoperative assessment is important to identify these patients at risk for

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perioperative complications. This should lead to an individualized perioperative approach from both the surgical and the anesthesiological perspective with the surgeon balancing efficacy and invasiveness of the planned surgical procedure and with the anesthesiologist planning for an adequate preoperative optimization, intraoperative monitoring and anesthesia technique as well as adequate postoperative surveillance and care.

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Advanced surgical techniques such as minimal invasive surgery have been implemented into clinical practice to improve postoperative outcomes. However, these are not the focus of this article and have been intensively reviewed elsewhere [44, 84, 104]. For the anesthesiologist

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several recommendations have been made to predict organ-specific postoperative morbidity, e.g. adverse cardiac events or even death. However, there still remains uncertainty about easy-

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to-use and inexpensive assessment tools allowing for a prediction of overall outcome. Furthermore, in many preoperative scenarios preoperative assessment is performed relatively late, often only a day prior to surgery opposing careful and effective preoperative planning.

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Who is the patient at real high risk? Due to many improvements made over the last decades modern anesthesia itself seems to be relatively safe with 0.68-0.82 anesthesia-related deaths in 100,000 cases [59, 60, 90]. Not

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surprisingly, all studies have shown that an increasing number of co-morbidities and age significantly influence the incidence of postoperative death [59, 60]. Basically, only for a small subgroup of patients surgery poses a significant risk with a high mortality rate [78].

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These mostly elderly patients represent only 12% of the overall population of surgical patients, who additionally suffer from diverse co-morbidities, which are briefly described in

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the following section of this article.

Age

In developed countries the demographic change steadily raises the number of elderly patients subjected to surgical procedures [2]. Hence, it can be expected that the increasing number of

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elderly patients will also enlarge the proportion of high risk patients. In the United States roughly about a third of all adults aged 60–69 years suffer from at least one chronic disease and a large proportion from two or more. In many elderly patients this was associated with

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functional limitations [80]. Although age itself has been shown in several studies to be an independent risk factor for perioperative mortality [26, 29, 64, 79], preoperative

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considerations should take the difference between biological and chronologic age into consideration, e.g. by assessing individual frailty [48].

Cardiovasular disease and perioperative risk The various efforts and advancements in the treatment of patients with cardiac diseases has led to a decrease of age specific cardiovascular deaths. However, worldwide the absolute number of cardiac deaths still increases as a result of the growing population [2]. Only in Western Europe the overall incidence of cardiovascular death is decreasing due to a slower 5

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population growth [86]. A significant proportion of patients with cardiac risk suffer from major adverse cardiac events after surgery (MACE) [20]. If perioperative myocardial infarction (MI) is diagnosed, intra-hospital mortality rises up to 25% [64], and with

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postoperative cardiac arrest mortality increases even up to 65% [101]. However, the incidence of postoperative overt MI diagnosis is relatively low with 0.4-0.5%, so that it contributes only 10% of overall mortality [29].

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On the other hand, apart from these well-known detrimental outcomes of overt postoperative MI there seems to exist another, so far unrecognized entity contributing additionally to a

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significant number of deaths after non-cardiac surgery: The VISION trial has shown that not only MI with clinical symptoms, but to a greater extent silent ”Myocardial Injury after Noncardiac Surgery”, which has been termed “MINS”, poses also a high risk to patients [102]. Here, a (mainly clinically silent) troponin elevation of >0.02 ng/ml was associated with a risk for 30-d mortality of 4-17%. Although it is now clear that patients with MINS are at great risk

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for harm in the postoperative period it remains unclear which differences between MINS and acute coronary syndrome without surgery exist. Furthermore, only little evidence exists whether and how to treat patients with slightly elevated troponin after surgery. To date only

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few studies, e.g. the MANAGE trial (Clinicaltrials.gov NCT01661101) or the INTREPID trial (Clinicaltrials.gov NCT02291419) try to address this important challenge for perioperative

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care.

Also, chronic heart failure (CHF) poses a major risk for perioperative mortality after noncardiac surgery, mainly if the ejection fraction is below 30% [38] and if other co-morbidities exist [37]. In about 25% of patients pre-existing CHF acutely exacerbates in the postoperative period [38], and perioperative mortality is therefore even 2-4 fold higher if compared to patients with isolated coronary heart disease [100]. As CHF is often underdiagnosed clinical signs should be carefully evaluated to detect patients at risk [40, 88]. A valid approach might be to determine biomarkers like brain natriuretic peptide (BNP) or NT-proBNP in patients 6

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with a history of CHF or a higher NYHA class as these markers have been shown to deliver independent prognostic information for perioperative and late cardiac events in high-risk

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patients [87].

Pulmonary disease and perioperative risk

Similar to cardiovascular disease, the incidence of pulmonary morbidity increases due to an

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ageing population. Although the estimates about the incidence and prevalence vary [95], it is clear that chronic obstructive pulmonary disease (COPD) is a major cause of death worldwide

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and also poses a threat in the perioperative period as it is often the reason for postoperative pulmonary complications (PPC). The latter can derive from either primary pulmonary disease or can occur as a secondary complication, e.g. during sepsis. In a recently published observational trial to evaluate a risk score for PPC (ARISCAT Score) the overall in-hospital mortality was 0.9%, but without PPC only 0.1%[69], i.e. most patients who died had some

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kind of postoperative pulmonary complications. Hence, patients with higher ARISCAT scores might be submitted to further pulmonary testing by an experienced specialist to clarify whether the patient´s pulmonary status can be improved preoperatively.

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Apart from pre-existing pulmonary morbidity also the anesthetic technique might significantly contribute to pulmonary complications in the perioperative period, in particular

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the use (or misuse) of neuromuscular blocking agents without neuromuscular monitoring [33]. Thus, it seems to be advisable to a) identify patients at risk for PPC and b) to pay particular attention in these patients to avoid postoperative residual curarization.

Obesity The incidence of obese patients in need of surgical treatment will further increase in endemic proportions [73]. Apart from the many logistic considerations for these patients many

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associated morbidities have to be taken into consideration as well, e.g. diabetes mellitus, hypertension, obstructive sleep apnea, developing chronic heart failure etc. [22]. Interestingly, a so-called adipositas paradoxon exists for critically ill patients as well as for

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surgical patients with a BMI between 30 and 40 kg/m2 [73]. In obese patients, perioperative mortality has surprisingly been described as being lower compared to all other BMI groups. The discussion about the clinical relevance of this to date unexplained phenomenon is still

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ongoing.

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Preexisting diabetes mellitus

Recent studies estimate that up to 8,5% of the population in Western industrialized countries will suffer from diabetes mellitus in the near future, the majority from type 2 diabetes [45, 92]. Diabetes, respectively the increased potential for perioperative dysglycaemia has been shown to be associated with numerous complications, mainly impaired wound healing,

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increased infection rate [17, 66] and cardiovascular complications [21, 99]. Patients with diabetes mellitus have a higher postoperative mortality of 3.5% compared to nondiabetic controls [53]. However, it has been shown that diabetes is often undiagnosed [1, 55] with up

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to 24% of all patients scheduled for elective surgery. Furthermore, several studies, mainly from ICU patients, suggest that glycemic variability puts patients at an even higher risk for

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complications and death than hyperglycemia alone [41]. A reliable biomarker identifying patients with diabetes mellitus should therefore potentially be useful to identify patients at risk for hyperglycemia and to prevent adverse outcome. Here, a preoperative HBA1c > 6% has been proposed as a predictor for an increased perioperative morbidity and mortality [24, 36, 46]. However, controversy still exists, in which cases HBA1c screening is justified [10]. One feasible approach might be screening for HBA1c in patients scheduled for major vascular and orthopedic surgery as these patients carry a very high risk for diabetes-associated complications [24, 47]. In other populations blood glucose testing or HBA1c screening might 8

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only be reasonable when clinical signs suggest an underlying diabetes mellitus, e.g. obesity, familiar disposition, history of impaired wound healing, higher age etc.

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Preoperative cognitive dysfunction and delirium Postoperative delirium (POD) can be frequently observed after major surgery and contributes to increased morbidity and mortality in the postoperative period [32, 105]. As POD is a result

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of a complex interplay of predisposing and precipitating factors a single risk factor for POD cannot be identified. Still, preoperative cognitive dysfunction [39] and age [3] have been,

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among others, found, to be relevant risk factors for POD as well as depression [82], poor mobility [76] and decreased age-associated functional reserve [48].

Hence, geriatric assessment as well as preoperative cognitive testing, e.g. with the 3D-CAM [67], FAM-CAM [98] or the Nurse Delirium Screening of Checklist (NuDESC) [75], should be an integral part of pre-operative risk assessment, mainly in elderly patients undergoing

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major surgery. However, many of the above mentioned easy-to-use tests still have to be validated for the preoperative period and are quite time-consuming, which makes the implementation into clinical routine problematic. In patients at risk for POD, depth of

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anaesthesia monitoring, for instance by BIS should be considered, as deep anesthesia in combination with burst suppression has been shown to be associated with increased incidence

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of POD [94].

Pre-existing organ dysfunction and anemia In many cases the impact of chronic liver disease is underestimated in the perioperative period, as symptoms of liver dysfunction or impaired liver functional reserve are subtle. However, chronic liver disease has been shown to be a relevant independent risk factor when added to the ASA class [79], i.e. the impact of liver disease is obviously not captured by ASA classification. Patients with chronic liver dysfunction often suffer from perioperative bleeding 9

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and are immune-compromised and hence prone to infection. Severe liver disease, such as a MELD score >14, should refrain the medical care team from elective surgery other than liver transplantation [77].

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Impaired kidney function, i.e. a decreased glomerular filtration rate, has also been linked to adverse postoperative outcomes not only as a risk factor for acute kidney injury (AKI) but interestingly also with an increased risk for major adverse cardiovascular events and

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cerebrovascular events (MACCE) [68].

Many clinical trials have identified anemia as a major risk factor being associated with

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significant perioperative morbidity and mortality [6]. Especially the combination of age, anemia and orthopedic surgery is common and poses the patient at high risk [96]. Anemia is naturally a risk factor for transfusion and in particular the transfusion-induced immunomodulation might negatively influence outcome in terms of bleeding, MACCE and even tumor recurrence rates. However, transfusion itself as cause of adverse outcome remains

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to be proven as only retrospective data have shown an association between transfusion and surgical site infection, disturbed wound healing and tumor-recurrence [97]. It might be that anemia in the elderly and morbid patient only points at an underlying fragility and poor

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outcomes [30].

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nutritional state similar as hypoalbuminemia has been shown to be linked to the same adverse

Timing of preoperative assessment Preoperative testing should aim to decrease surgical risk without interfering profoundly with surgical schedules. Hence, the ideal time for preoperative risk assessment is as early as possible, ideally at the same day when surgery is judged to be indicated and not just the day before surgery, as it is unfortunately still common in clinical reality [13]. Preoperative physical training and exercise has been shown in several randomized clinical trials and settings to significantly improve postoperative outcome [5, 14, 50]. In some cases it 10

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might therefore be beneficial for the patient to identify individuals with a high risk for cardiovascular or pulmonary complications and assign these patients to a “prehabilitation path”, which might improve functional capacity [11, 85].

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Principally, the perioperative use of beta blockers can improve survival in patients with high cardiovascular risk [65]. However, caution is recommended when initializing beta-blocker therapy in the perioperative period as it can increase the incidence of postoperative stroke

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[34]. This observation has led to the revised 2014 ESC/ESA guidelines on cardiovascular assessment and management in patients undergoing non-cardiac surgery [52]: As before,

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continuation of beta-blocker therapy is strongly recommended in patients chronically receiving this medication. Withdrawal of chronic ß-blocker therapy is definitively detrimental for patients undergoing surgery [103]. Conversely, the initiation of beta-blocker therapy might only be considered in patients who have known ischemic heart disease (IHD) or myocardial ischemia [52] and should be goal-directed, i.e heart rate targeted, and should be initiated 2-20

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days prior to surgery. Likewise, initiation of perioperative statin therapy [19], optimizing anticoagulation therapy [23] or anemia therapy with iron [54] prior to surgery is also timeconsuming. Therefore, all approaches require a timely risk assessment by the

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anesthesiologist/cardiologist to allow for optimal preoperative optimization.

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Preoperative Assessment

Patient classification and functional capacity Preoperative evaluation is undergoing a profound change from preoperative routine testing to a more individualized risk evaluation. Such a personalized approach does not only provide the required information about the individual patient, but can also significantly reduce costs [13]. The long-established American Society of Anesthesiologists (ASA) classification is basically an “eye-balling” by the anesthesiologist. Still, in many multivariate analysis the ASA classification has mostly been proven to be a strong independent predictor of various adverse 11

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outcomes. In most multivariate analyses many other comorbidities are deleted as an independent predictor as their impact on outcome is cross-correlated to (already covered by) ASA classification (except liver disease, see above). For instance, cardiac risk can indirectly

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be captured by ASA classification as patients with coronary heart disease (CHD) or ASA class 3 already show a perioperative mortality of about 5% [26]. However, the ASA classification was not designed to specify individual cardiac risk. A more accurate prediction

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of cardiac events is achieved when ASA classification is combined with specific cardiac risk scores [81]. Another limitation of the ASA classification is the lack of inclusion of the risk of

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planned surgery.

Another form of assessing perioperative risk is the estimation of functional capacity, which is also often “eyeballed” by a questionnaire regarding activities of daily life and is categorized in metabolic equivalents (METs). Here, estimation of <5 metabolic equivalents (METs) has been associated with an increased risk for perioperative complications [83]. Functional

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capacity is more reliably assessed via a structured interview, e.g. by using validated questionnaires [70], but if these time-consuming procedures can be implemented into daily

Risk scores

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routine remains to be seen.

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More recent risk scores can identify and quantify cardiac risk in a more accurate fashion. The revised cardiac risk index (rCRI) [57] or its modified form (mrCRI) [25] have been shown to provide a robust predictive value for postoperative major cardiovascular events [4, 27]. When combined with other risk stratification techniques, for example the assessment of functional capacity via the aforementioned METs the predictive value improves even further [9]. A more recent score is based on the data of the National Surgery Improvement Program (NSQIP). The NSQIP surgical risk calculator has been proposed as a valuable scoring approach to predict perioperative cardiac risk if available [52]. Still, these NSQIP databank-based risk calculators 12

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have yet to be validated for their reliability and under differing health care conditions outside the US [88]. A disadvantage of the NSQIP score is that calculation of the score requires an access to the internet, as the underlying model is not public domain.

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The risk for pulmonary complications might be assessed with specific risk scores. The above mentioned “Assess Respiratory Risk In Surgical Patients in Catalonia” (ARISCAT) score [69], which was initially developed in a Catalonian cohort, was later on validated in a large

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international cohort in the “Prospective Evaluation of a RIsk Score for postoperative pulmonary COmPlications in Europe” (PERISCOPE) trial. However, it cannot distinguish

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between primary (e.g. pneumonia) and secondary (i.e. indirect or remote pulmonary injury) postoperative pulmonary complications (PPCs). Other risk indices have been proposed as well, e.g. the respiratory failure risk index or the postoperative pneumonia risk index [42]. Very recently, le Manach et al. introduced and validated the Preoperative Score to Predict Postoperative Mortality (POSPOM), which showed very good discriminative and calibration

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properties using 17 predictors in a regression model[56]. Easy-to-use tools like these might help the physician in preoperative decision making. Biomarkers

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Preoperative biomarkers have gained increasing attention over the last years. In particular “Pro-brain natriuretic peptide” (Pro-BNP) or “N-terminal-proBNP” were shown to have a

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surprisingly high predictive value for postoperative cardiac complications and death. These markers are at least equal and might even be superior to the afore mentioned cardiac risk scores in predicting adverse cardiac events [62]. By implementing these tests into clinical practice the currently often requested cardiology consult might be limited to patients in need of a coronary intervention or if an optimization of conservative cardiologic therapy is deemed necessary [52], but not necessarily for risk assessment alone. As postoperative complications and mortality are most likely also influenced by genetic factors, genetic screening could be thought to become integral part of routine preoperative 13

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testing in the future [91]. However, at present the predictive value of genetic haplotypes is very low compared to clinical risk factors. Thus, the added value of genetic testing is (and

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will be for the near future) questionable.

Practical approach: how to organize preoperative evaluation and improve perioperative care

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Several models to implement a structured and standardized risk assessment have been proposed. The anesthesiologists might serve as a coordinator for multidisciplinary efforts on

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preoperative patient assessment [43, 89].

In the following section of this article the authors will try to present a feasible practical approach to preoperative risk evaluation. The authors are well aware that only low evidence exists for some of the proposed approaches. However, by combining and applying the currently available tools, even if a single measure is not evidence based, the overall risk for

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patients might be better identified and eventually significantly decreased by appropriate intraand postoperative management.

consequences!

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Role of the Anesthesiologist: No diagnostics if it would not eventually lead to therapeutic

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Preoperative risk evaluation should be ideally conducted by experienced anesthesiologists in an ambulatory setting allowing for a timely and systematic examination of the patient. Hence, the first contact between anesthesiologist and patient should ideally take place about when the operation is scheduled, which is often several days or even weeks prior to the surgical intervention. A well-organized interplay between surgical and anesthesiological partners during the preoperative period is thus required. The establishment of an Anesthesia Preoperative Evaluation Clinic (APEC), which should ideally be closely located to the

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surgical outpatient services can greatly improve the preoperative coordination and risk evaluation [89]. Furthermore, risk assessment itself should be performed in an structured and standardized

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manner and should ideally be fixed in form of standard operating procedures (SOPs), which have to be easily accessible for the respective anesthesiologist [51]. This is not only helpful

reduce costs and improve quality of care [12]. The anesthesiologist might then take the following steps:

Check identity and the planned surgery. Evaluate the risk of the scheduled surgical

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for anesthesiologists in training, but also allows for an individualized procedure, which can

procedure using the well-evaluated ACC/AHA or J. Hopkins recommendations or a similar classification [25, 31, 37]. -

Perform an adequate physical examination. This should include the auscultation of heart and lung as well as a standardized search for signs of a possible difficult airway

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(head/neck mobility, mouth opening, dental records, Mallampati´s classification [63]) Early estimation of a possibly difficult airway has been shown to significantly reduce the need for an emergency surgical airway [7]. Also, inspect possible regions for

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venous or arterial puncture.

Search for relevant findings indicating increased anesthesia-associated risk (allergy to

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anesthetics, complications during preceding surgery and/or anesthesia, history of bleeding).

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Document the patients´ BMI. Despite of the above mentioned obesity paradox [73] a BMI > 35 kg/m2 should trigger specific questions assessing metabolic, pulmonary and cardiac risk. Furthermore, a modified clinical path for obese patients should be initiated, which considers logistical questions and plans for adequate postoperative care [58]. Additionally, it might be feasible to determine the HBA1c level in obese patients. If HBA1c > 8,5% without a preexisting diagnosis of diabetes mellitus a 15

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diabetes specialist team should be consulted as early as possible [71]. Also look for glycemic variability in the perioperative period in these patients and ensure that glucose levels remain between 108-180 mg/dl in the perioperative period [72]. Perform preoperative testing for possible cognitive dysfunction in the elderly using

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evaluated tests. Here, the NuDESC [75] or easier-to-use versions like the 3D-CAM [67] might be feasible although they have not been evaluated for the preoperative

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phase. Possibly perform the chosen tests together with a well-evaluated frailty score [48]. This allows for a reliable identification of patients at risk for postoperative

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cognitive dysfunction (POCD) or delirium.

A feasible approach to determine preoperative cardiac risk is depicted in table 1. The process should include the assessment of the surgical risk as described above, the determination of the functional capacity (inability to climb less than 2 flights of stairs indicates ≤ 4 metabolic equivalents [52]) and the number of clinical risk factors

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(evaluated with the mRCRI or online using the NSQIP-MICA calculator). Only in high-risk patients (high risk surgical procedure, ≤ 4 METs and a mRCRI > 2) further diagnostic tools should be considered, e.g. assessment of biomarkers (troponin, BNP

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and NT-proBNP), registration of a preoperative ECG or TTE as well as cardiac stress testing [52].

Preoperative pulse oximetry should be performed routinely to assess possible

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pulmonary risks. Room air arterial oxygen saturation has been demonstrated to be the most relevant factor in predicting postoperative pulmonary complications (PPCs), e.g. it is an integral part of the already well-evaluated and reliable ARISCAT score [69]. Patients with 26-44 points are at medium risk, patients with > 44 points are at high risk for PPCs [15]. Pulmonary function testing by a specialist should be limited to major thoracic and abdominal surgery in the presence of known pulmonary disease or prior to lung surgery [8, 93]. 16

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Identify the anemic patient. A practical approach for the identification and treatment of anemia is demonstrated in Figure 1. Only if the surgical procedure is scheduled in more than two weeks (“elective surgery”) and is predefined as an “indexoperation”

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with a high probability of bleeding, the hemoglogin status should be evaluated. Here, hemoglobin measurement via fingerclip has been demonstrated not to be suffieciently reliable, especially in a setting of blood loss [18, 74]. In case of anemia according to

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the WHO definition [16] an “anemia consult” is triggered allowing for specialized diagnostics and preoperative treatment of anemia if feasible. Document all examinations and findings.

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Always follow the rule: No diagnostics if no therapeutic consequences!

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Role of the Specialist: Can the patient´s health status be improved preoperatively? In most cases structured risk evaluation by the anesthesiologist determines the individual level

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of intra- and postoperative care and mostly the preoperative assessment can be performed by anesthesiologists. However, a morbidity severely affecting the patient´s compensatory physiological mechanisms might call for a more elaborate diagnostic procedure and the

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evaluation by an experienced specialist. Here, the main question to be answered should be whether the patient´s health status can be improved preoperatively. Pharmacological

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preoperative re-compensation of severe cardiac and pulmonary morbidities, treatment of anemia in cases of surgery with bleeding risk or newly diagnosed diabetes mellitus are some examples, where consultation of a specialist might help to reduce perioperative risk. This ensures an optimal perioperative care, but unfortunately an additional diagnostic workup performed by specialists is time-consuming and expensive [89] and thus should be the result of careful risk assessment by the anesthesiologist.

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Systematic and structured preoperative risk assessment with the abovementioned approaches might allow for improvement of perioperative quality of care [12] and might reduce costs by avoiding redundant preoperative testing and consultative services. Hence, preoperative

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evaluation should be ideally conducted by experienced anesthesiologists. This could also be complemented with the implementation of a call center assessment and the use of an extended checklist for pre-screening of elective surgical patients as it has been already successfully

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shown [61].

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Practice Points

A relatively small subgroup of multimorbid and elderly patients is at significant risk for postoperative complications and death. Precise and timely risk assessment by experienced anesthesiologists is pivotal to

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reduce the still high perioperative morbidity and mortality. Perform individualized risk evaluation instead of routine testing in a standardized and

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structured manner. Fix the evaluation process in form of standard operating procedures (SOPs) to allow for better planning and performance.

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Use validated risk scores and novel biomarkers, which identify relevant comorbidities.

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If an identified comorbidity severely affects the patient´s compensatory physiological mechanisms the consultation of an experienced specialist might become necessary. Focus on the question whether the patient´s health status can be improved preoperatively. 18

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Research Agenda Future work should focus on linking pre-, intra- and postoperative risk stratification techniques to improve overall outcome.

Acknowledments

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None

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Financial Support This work was not supported by any institution

Conflict of Interest

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The authors declare that they have no conflict of interest.

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Legends to Figures and Tables

Figure 1 Algorythm to identify and treat preoperative anemia: Only if anemia is diagnosed in cases of

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elective surgery and a high probability of intraoperative bleeding (=Index Operation) an “Anemia Consult” is triggered allowing for specialized diagnostics and preoperative treatment

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Two-step approach to preoperative evaluation of cardiac risk: Only after having assessed surgical risk, functional capacity and the number of clinical risk factors determined with the

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mRCRI (light blue) further procedures might be considered (darker blue) (mod.[35]).

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Table 1

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Figure 1

1