Thermoregulation is commonly disturbed as a result of low ambient temperatures in the operating room as well as the effects of anesthesia. Thermoregulation is important in maintaining hemostasis by reducing coagulopathy and the amount of surgical blood loss, thereby avoiding the risk of blood transfusions and products. Hypothermia is associated with lower metabolic rates, immunologic changes that increase the risk of surgical site infections, delays in recovery, and separation from mechanical ventilation [49–51]. The incidence of hypothermia can be reduced with accurate temperature measurement and assiduous attention to ambient room temperature, patient draping, warming intravenous solutions and blood products, warming ventilator circuits, and the use of warming blankets.

Age is an independent risk factor for poor outcomes and knowledge of age-specific risks creates an opportunity to anticipate and mitigate these risks (https://​www.​facs.​org/​~/​media/​files/​quality%20​programs/​geriatric/​acs%20​nsqip%20​geriatric%20​2016%20​guidelines.​ashx). Postoperative delirium is an example of a frequent, insidious complication which is observed in 30–50 % of patients after major surgery and as high as 75 % in patients over age of 70. It is commonly seen in the older age group and is associated with short and long term increased mortality, morbidity, and LOS. Mitigation strategies include vigilant monitoring, careful analgesia, vision and hearing aids, mobility, quiet and reassuring surroundings, and an active effort to maintain circadian day–night schedules where possible. Adding a clock to patient’s rooms has been shown to reduce delirium and confusion. Jung determined that the incidence of delirium in frail cardiac surgery patients was 3–8-fold higher [52]. Additionally, increased risks in the elderly include falls, infection, and pulmonary complications accounting for 40 % of postoperative complications and 20 % of potentially preventable deaths [53].

Lower than normal body mass index (BMI) consistently confers a surgical risk, while overweight patients may have an increase in wound complications and deep venous thrombosis. These patients, however, are not at increased risks of death and other major complications. In fact, some higher and BMI patient populations appear to exhibit fewer perioperative complications, operative mortality, and better long term survival. This phenomenon is often referred to as the “obesity paradox .” Mullen et al. reviewed 118,707 non-bariatric general surgical patients using the NSQIP database and observed that BMI’s influence on mortality exhibited a reverse J-shaped relationship, with the highest rate of death in underweight and extremely morbidly obese patients while the overweight and moderately obese had the lowest mortality rates [54]. These observations are in contrast to mortality in the “general medical” population in which obesity reduces longevity, hence the “paradox.” The study also demonstrated a direct correlation between BMI and complications particularly surgical site infections (SSI) . The authors also demonstrated that obesity is not a risk factor for postoperative mortality or major complications after major intra-abdominal cancer surgery while underweight patients experienced a fivefold increased risk of postoperative mortality [55]. Ramsey and Martin have suggested that elevated BMI increases operative complexity in pancreatectomy but that the increased risks associated with BMI may be reduced with modifications in techniques and meticulous perioperative care [56]. Underweight and extremely high BMI patients experience greater risk while mild obesity wasn’t found to be a risk factor for 30-day outcomes after vascular surgery and actually appeared to confer an advantage [57]. Studies examining the influence of BMI on spine surgery outcomes have produced mixed results. There appears to be an increased risk in high BMI patients undergoing revision spine surgery but not cervical fusion [58, 59]. Cardiac surgery patients are similarly impacted by weight, where low BMI and extremely high BMI confer an increased risk. Although an increased BMI may adversely alter some recovery processes while simultaneously reducing hemorrhage and transfusions [60]. Stamou demonstrated that overweight cardiac surgery patients have lower operative mortality and a better 5-year survival than patients with a normal BMI supporting the “obesity paradox” phenomenon [61]. Johnson et al. corroborated these findings in 78,762 cardiac surgery patients where overweight and mildly obese patients had better outcomes than the underweight and the morbidly obese did [62].

A history of a stroke, seizure, movement disorders, and other neurological conditions confer additional risks and can adversely affect outcomes in surgical patients. The ability to assess pain accurately is important in providing patient comfort, preventing immobility and atelectasis. Several useful pain scoring systems may be utilized [63–65]. The use of neuraxial and opioid anesthesia has been shown to reduce operative mortality by 30 % in a meta-analysis comparing neuraxial blockade with general anesthesia [47, 48].

A history or evidence of chronic respiratory insufficiency or other respiratory conditions can impact perioperative care and elevate operative risks [66]. It is essential that we develop and agree on common definitions across different disciplines treating the patient [67]. Spirometry and formal pulmonary function testing, arterial blood gases, and chest radiography should be obtained in the evaluation of these high-risk patients particularly in patients undergoing thoracic and abdominal procedures. Smoking cessation 30 days prior to operation is strongly recommended and is often coupled with counseling and nicotine replacement; however, smoking cessation of seven or less days can actually increase pulmonary secretions and pulmonary complications [68, 69]. Pulmonary rehabilitation appears to be beneficial in reducing pulmonary risk although its impact needs more intensive study [70–72].

Postoperative respiratory complications occur in approximately 3–6 % of surgical patients and most risk models commonly include respiratory data such as active smoker status, chronic obstructive pulmonary disease, dyspnea, and active pneumonia. In addition, assessing functional status, ASA class, renal insufficiency, and other cardiopulmonary conditions are important elements of a comprehensive evaluation in patients undergoing major surgery [73–76]. As an example, ARISCAT provides preoperative pulmonary-specific risk assessment which takes into consideration age, oxygen saturation, and other clinical factors as well as the location of the surgical incision, the duration of surgery among other elements [74]. ARISCAT categorizes risk as follows: 0–25 points low risk and is associated with a 1.6 % pulmonary complication rate, 26–44 points intermediate risk, and a 13.3 % pulmonary complication rate, while 45–123 points suggests high risk and is associated with a 42.1 % pulmonary complication rate (http://​www.​uptodate.​com/​contents/​calculator-ariscat-canet-preoperative-pulmonary-risk-index?​source=​search_​result&​search=​risk+calculator&​selectedTitle=​7~150).

Mechanical ventilation can be a contributory factor in the development of postoperative acute lung injury and acute respiratory distress syndrome (ARDS) [76]. It is associated with mechanical ventilation, inspired oxygen fraction, the administration of crystalloid volume intravenously, as well as transfusion of homologous blood components [77]. In contradistinction to pulmonary barotrauma in which pulmonary damage is the result of excessive airway pressures, the mechanism of injury from volutrauma is likely to over distention of alveoli from excessive excessively high tidal volume settings and injury to the alveoli epithelium. Early extubation after surgery, particularly in patients with pre-existing lung disease, may reduce the incidence of both barotrauma and volutrauma and has been correlated with improved outcomes [78, 79]. Intraoperative alveolar recruitment using PEEP, maintenance of tidal volumes of 6–7 ml/kg, and postoperative utilization of non-invasive positive pressure ventilation are protective ventilator strategies known to reduce the incidence of postoperative respiratory complications [80, 81]. Hypercapnia is another lung protective strategy that has been proven meritorious [82, 83].

In thoracic surgery, dependent, bedridden living correlates with 7–8-fold increased risk of mortality, nine fold prolonged ventilation rate, and three fold more likely to require reintubation [84]. The predicted postoperative lung function after lung resection is typically greater than what is witnessed clinically by at least 30 % and is most disparate on the first postoperative day with subsequent progressive improvement [85, 86].

The Thoracoscore, a convenient and useful risk scoring system in thoracic surgery, was the result of an in-depth analysis of 15,183 thoracic surgery patients where in-hospital mortality correlated with ASA classification, age, gender, dyspnea score, performance status, priority of surgery, diagnosis group, procedure class, and comorbid disease. Modifiable risk factors to reduce the risk of complications include weight loss, smoking cessation, and a multidisciplinary approach towards optimizing lung functions including exercise, patient education, as well as the treatment of bronchorrhea and bronchospasm [87, 88].

The preoperative evaluation of the high-risk patient with cardiovascular disease should focus on assessing the risk of perioperative myocardial ischemia and infarction and the identification of significant cerebrovascular disease, congestive heart failure and ventricular dysfunction, rhythm abnormalities, and pulmonary hypertension [89]. Lab testing may include biomarkers such as BNP. Treadmill exercise testing is readily available and well-studied [90]. Additional imaging can include many variations of echocardiography, nuclear testing, computerized axial tomography, coronary artery calcium (CAC) score, magnetic resonance imaging (MRI), and coronary angiography with or without ventriculography and, more recently, fractional flow reserve-FFR, as indicated.

In 1977, Goldman developed the eponymous cardiac risk scoring systems for patients undergoing non-cardiac surgery which was revised by Lee et al. (RCRI) in 1999 making it simpler and more predictive [91]. The risk factors are tallied and are correlated with the risk of major cardiac complications. Zero risk factors has a 0.4 % risk of death, 1.0 % with one risk factor, 2.4 % with two risk factors, three or more risk factors carry a risk of 5.4 % [16].

The Vascular Study Group of New England (VSGNE) studied the vascular surgery population’s risk of adverse cardiac events and has developed the Vascular Study Group Cardiac Risk Index (VSG-CRI) [17]. Additional investigations utilizing the American College of Surgeons’ NSQIP database reinforces the importance of surgery type, ASA classification, functional status, age, as well as renal dysfunction [92]. CAC score improves preoperative assessment and is able to assign patients to various risk categories in order to modify processes and care plans accordingly [93].

The impact of drugs to mitigate cardiovascular risk has been well-studied, albeit controversial, and continues to evolve. For example, the PeriOperative ISchemic Evaluation (POISE) trial evaluated metoprolol in patients at increased risk for perioperative cardiovascular events (death, myocardial infarction, and nonfatal cardiac arrest) [94]. While significantly fewer cardiovascular events were noted in the treatment group, metoprolol was associated with an increased risk of death and stroke potentially related to the observed perioperative hypotension. Clonidine has also demonstrated similar hypotensive effects and nonfatal cardiac arrest and failed to reduce the risk of death or myocardial infarction [95]. Aspirin has been shown to have no beneficial impact on a composite measure which includes death and myocardial infarction and increases the risk of bleeding [96]. Combinations of these strategies have been reported including the use of neuraxial blocks with general anesthesia which wasn’t associated with an increase in adverse cardiovascular outcomes in the POISE-2 study [97].

Valvular heart disease is increasingly recognized in our aging patient population. The effects of volume loading on left ventricular function occurring in mitral regurgitation as well as the pressure load in aortic stenosis, particularly in the setting of depressed myocardial contractility, carry considerable risk. These conditions must be recognized during the preoperative evaluation and anesthetic as well as surgical techniques modified to optimize outcomes [98]. Atrial fibrillation commonly accompanies valvular heart disease although non-valvular atrial fibrillation (AF) is more common. Regardless of its underlying cause AF can affect cardiac performance especially with a poorly controlled heart rate and pose thromboembolic risk. The CHA2DS2-VASc (Congestive heart failure, Hypertension, Age >75, Diabetes, prior Stroke/transient ischemic attack, VAScular disease) risk stratification score for estimating stroke risk in non-valvular AF ranges from 0 to 9 points as shown in Table 34.3 (http://​www.​uptodate.​com/​contents/​calculator-cha2ds2-vasc-risk-stratification-score-for-estimation-of-stroke-risk-for-nonvalvular-atrial-fibrillation?​source=​search_​result&​search=​risk+calculator&​selectedTitle=​5~150). Appropriate perioperative anticoagulation strategies can mitigate the risk of atrial fibrillation associated emboli.

Aortic surgery and other major vascular procedures are frequently associated with a high risk for adverse cardiac events and mortality. Investigation of this subset of patients highlights importance of ASA class, age, and preoperative organ dysfunction as essential elements of risk assessment and mitigation strategies [99]. In patients undergoing left ventricular assist device (LVAD) implantation postoperative right ventricular dysfunction can be a vexing problem. A right ventricular failure risk score (RVFRS) has been developed which attributes points to preoperative vasopressor requirements as well as to elevated serum levels of aspartate aminotransferase, bilirubin, and creatinine to predict the need for postoperative inhaled nitric oxide, inotropic support, and mechanical support of the right heart [100].

The history and physical exam should be focused (looking for jaundice, signs of portosystemic shunting, ascites, encephalopathy, etc.) to elucidate liver dysfunction as well as altered bowel and pancreatic dysfunction. A patient with advanced hepatic cirrhosis is simple to identify, but less pronounced degrees and other hepatic disorders may be overlooked with considerable consequence(s). It is vital to elucidate the amount and limits of the functional reserve. Timing of operation and avoiding hepatic insults (pharmacologic and hemodynamic) are central to successful anesthesia and perioperative care.

The Model for End-Stage Liver Disease (MELD) is clinically valuable and relevant, categorizing patients via bilirubin, creatinine, International Normalized Ratio (INR), and the etiology of underlying liver dysfunction [101]. MELD scoring has also been compared favorably with others systems, such as the Child-Turcotte-Pugh classification [102]. Common problems in patients with liver dysfunction include coagulopathy 2–28 % and hemorrhage, immuno-incompetence and sepsis 9–58 %, malnutrition, cardiomyopathy with systolic dysfunction and/or diastolic dysfunction, and peripheral vasodilation, pulmonary dysfunction 6–29 %, and renal dysfunction 5–79 % [103].

Liver dysfunction increases mortality of patients undergoing cardiac surgery, where coagulopathy and hemorrhage are commonplace, and progressively increases with the severity of liver dysfunction. The MELD score has proven useful for risk assessment and planning in the cardiac surgery population [104]. Liver resection also poses a discrete and identifiable risk to patients with liver dysfunction. Four independent risk predictors include ASA class, aspartate aminotransferase level, extent of liver resection (>3 vs <3 segments), and the need for an additional hepaticojejunostomy or colon resection [105].

Intestinal and pancreatic exocrine deficiency may emanate from a variety of diseases, have a myriad of signs and symptoms, but the greatest functional risk relates to malnutrition. Gastrointestinal, colon, and rectal surgery are common procedures, where ASA class, age, BMI, prolonged and open procedures (vs. laparoscopic techniques), active smoking, chronic obstructive pulmonary disease (COPD), kidney dysfunction, corticosteroid use, and sepsis have been correlated with increased risk [106]. Pancreaticoduodenectomy is a high-risk procedure and significant predictors of morbidity include functional status, increased age, obesity, COPD, kidney disease, corticosteroid use, hypoalbuminemia, hemorrhagic diathesis, and leukocytosis. Significant predictors of 30-day mortality included COPD, hypertension, neoadjuvant radiation therapy, elevated serum creatinine, and hypoalbuminemia [107].

Perioperative bowel prep regimens can be beneficial with recent studies suggesting that mechanical bowel prep should be accompanied with oral antibiotics in colon and rectal surgery to reduce the risk of surgical site infections, anastomotic leak, and ileus. The use of mechanical bowel prep and oral antibiotics may also reduce length of stay and readmissions [108–110]. The use of H2-blockers and proton pump inhibitors can markedly reduce the risk of stress induced gastrointestinal hemorrhage , but may increase the risk of hospital acquired pneumonia [111].

The targeted history and physical, searching of renal dysfunction is commonly accompanied by urinalysis, serum creatinine, and calculation of glomerular filtration rate. Imaging is less commonly utilized than for cardiac and pulmonary evaluations, but ultrasonography, radiography, and endoscopy may be useful in certain circumstances.

Perioperative renal dysfunction is common and often unrecognized [112]. Patients may suffer various degrees of acute kidney injury (AKI) , without the need for dialysis, and incur increase short and long term risk. Ableha et al. reported on 1597 patients and found ASA classification, emergency and high-risk surgery, age, ischemic and congestive heart disease, and RCRI score significant predictors for the development of AKI, in patients needing intensive care after surgery [113]. AKI is linked with increased risk of mortality and longer LOS and these risks are documented extensively in adult cardiac surgery [114–118]. Various risk models have been developed and commonly include age, BMI, hypertension, peripheral vascular disease, chronic pulmonary disease, serum creatinine concentration, anemia, previous cardiac surgery, emergency operation, and operation type [119–121] (http://​riskcalc.​sts.​org/​stswebriskcalc/​#/​calculate). AKI risk mitigation strategies include avoidance of nephrotoxic drugs—e.g., aminoglycosides, amphotericin B, and ionic contrast. Pretreatment with sodium bicarbonate and fenoldopam haven’t stood the test of time. Delay after ionic contrast administration appears important, though many details remain to be understood. More recently, high-chloride intravenous fluids are thought to be associated with a significantly higher risk of acute kidney injury [122].

Goal directed therapy (GDT) , also known as goal directed hemodynamic management, is well studied and maintains considerable promise as a modifiable risk in AKI and renal failure [123–125]. A prospective study is underway to further define the utility of this strategy [126].

The targeted history and physical should elucidate risks which include thyroid dysfunction, adrenal insufficiency, and pancreatic endocrine abnormalities, most commonly diabetes mellitus, which also adds considerable, additional risk. Considerable controversy exists, despite extensive research, in the management and risk mitigation of perioperative hyperglycemia. Hyperglycemia is linked with death, surgical site infection, and atrial fibrillation in the cardiac surgery patient and various protocols have been developed to provide glycemic control [127].

The history and physical must elucidate risks (malnutrition, vitamin, and trace mineral deficiency central to wound healing, diabetes mellitus, immunosuppression, infection, peripheral occlusive vascular disease, immobility, genetic defects, radiation therapy and chemotherapy, smoking, etc.) which can impair recovery, either through development of problems such as pressure sores/ulcers or non-healing wounds. Tests such as ankle-brachial indices, transcutaneous oxygen saturations, and quantitative wound cultures may augment expert evaluation and decision making.

Proper planning, positioning, and padding are imperative during operative procedures to prevent pressure sores. Considerable investigation has been devoted to wound closure and includes type of suture, monofilament vs. braided, permanent vs. absorbable, skin closure with sutures and staples, and a multitude of dressings. In cardiac surgery, various techniques for sternal closure after median sternotomy have been investigated and the role of “rigid sternal fixation” to prevent dehiscence and/or infection is currently unresolved. Skin cleansing, wound closure, and support have been vigorously marketed, but evidence for value is scarce. A complete review of adjuncts, such as wound healing factors and hyperbaric oxygen, is beyond the scope of this text.

Comprehensive, postoperative care will include attention to skin, dressings, mobility, nutrition, etc., in order to reduce the risk of pressure sores and wound problems. Skin can be assessed in combination with the Braden Scale, with special attention to sensory perception, moisture, activity, mobility, nutrition, and friction or shear. Glucose control is thought to be important in preventing sternal wound infections after sternotomy and various other surgical site infections as well. Wound evaluation should also be included in the comprehensive, postoperative routine (http://​www.​uptodate.​com/​contents/​calculator-pressure-ulcer-risk-stratification-braden-score?​source=​search_​result&​search=​risk+calculator&​selectedTitle=​8~150130; http://​www.​uptodate.​com/​contents/​wound-healing-and-risk-factors-for-non-healing?​source=​search_​result&​search=​wound+closure&​selectedTitle=​9~95).

Negative pressure wound therapy has a long history, is well studied, and commonly utilized. The use of “wound vacs” has simplified wound care, makes management of open and infected wounds more comfortable for patients, and accelerates wound healing. The archetype for this growing use and experience is the infected sternal wound, where topical negative pressure is commonly thought to be superior to traditional methods of irrigation and packing [128, 129]. “Wound vacs ” are also commonly utilized to assist in preventing wound infections associated with delayed sternal closure.

The comprehensive history and physical will include special attention to metabolic and nutritional signs and symptoms that increase the risk of recovery. Wound healing may be impaired with various metabolic maladies and commonly with malnutrition—where attention should focus on weight loss, loss of muscle and subcutaneous fat, and edema. Laboratory tests to be considered include electrolytes, BUN, Cr, etc. Markers of protein status (albumin, transferrin, and pre-albumin) may be valuable in select patients. Malnutrition can increase the risk of infection related to impairment of cellular and humoral immunity, poor wound healing, pressure ulcers, etc. Nutritional intervention has been shown to be valuable in various areas. Enteral, parenteral , and targeted repletion of vitamins and trace metals have been studied and should be considered when appropriate to mitigate surgical and perioperative risk [130, 131].

The history and physical must elucidate risks associated with anemia, coagulopathy, infections, and related factors that would suggest increased risk of intraoperative and postoperative problems. Anemia is commonly associated with surgical patients and will often lead to increased use of blood products although with unclear benefits. In fact, according to the STS-NCD in 2014, 43.2 % of coronary artery surgery patients received blood transfusions. Much has been written about the considerable, negative impact (death and complications as well as cost) of this phenomenon. Consideration should be given to preoperative diagnosis and correction of anemia with iron, vitamin B12, folate supplementation, or administration of recombinant human erythropoietin [132]. Investigations continue to refine our understanding of the risks of anemia and transfusion and aim to optimize our management of these common and vexing issues [133].

Coagulopathy is important, albeit less commonly recognized than anemia. Hypercoagulable states can lead to deep venous thrombosis (DVT) , which has a lower clinically recognized incidence than when imaging is routinely utilized for screening. DVT is associated with pulmonary thromboembolism, which is low incidence, but potentially catastrophic. The DVT Geneva risk scoring system suggests the following risks: heart failure, respiratory failure, stroke, MI, infection, rheumatic disease, cancer or myeloproliferative disorder, nephrotic syndrome, prior thromboembolic disorder, hypercoagulable state, immobility, travel, age, increased BMI, venous insufficiency, pregnancy, hormonal therapy, and dehydration. Points attributed to the presence of each risk correlate with incidence: 0–2 lower risk—0.8 % 30-day risk of symptomatic VTE or VTE-related mortality, 3–30 points higher risk—3.5 % 30-day risk of VTE or VTE-related mortality (http://​www.​uptodate.​com/​contents/​calculator-geneva-risk-score-for-venous-thromboembolism-in-hospitalized-medical-patients?​source=​search_​result&​search=​risk+calculator&​selectedTitle=​6~150). Caprini has investigated postoperative venous thromboembolism and also categorized patient’s risk with 20 variables: low (0–1, 34.5 %), moderate (2–4, 48.5 %), or high-risk (more than 4, 17.2 %) categories. DVT prophylaxis wasn’t utilized as commonly as guidelines would recommend and mechanical prophylaxis with sequential compression devices was utilized more frequently than chemoprophylaxis [126, 134–135].

Hemorrhagic diathesis is less common than anemia and DVT. Hemophilia and platelet disorders must be elucidated and an appropriate plan for safe intraoperative management and postoperative care coordinated with a hematologist and anesthesiologist. Increasingly, genetically engineered coagulation factors and concentrates are available, limiting the risk associated with blood product transfusion. Acquired coagulopathy is increasing with the use of various anticoagulants for atrial fibrillation, coronary and cerebrovascular disease, as well as side effects of non-traditional medical remedies. The HAS-BLED bleeding risk score is useful and includes age, liver dysfunction, renal dysfunction, bleeding tendency, warfarin and antiplatelet drug use, and alcohol excess [136]. The risk is tallied with 0–9 points and bleeds range from 1.13 per 100 patient-years to 8.7 bleeds per 100 patient-years with four points, with greater than or equal to three points suggesting high risk. Insufficient data for 5–9 points precludes forecasting, but the risk remains high (http://​www.​uptodate.​com/​contents/​calculator-clinical-characteristics-comprising-the-has-bled-bleeding-risk-score?​source=​search_​result&​search=​risk+calculator&​selectedTitle=​10~150; http://​www.​uptodate.​com/​contents/​perioperative-management-of-patients-receiving-anticoagulants?​source=​search_​result&​search=​perioperative+an​ticoagulation&​selectedTitle=​1~150).

A complete review of pharmacologic agents that impair coagulation is beyond the scope of this text, but the clinician should be familiar with characteristics of common drugs, including half-life of effect, bridging and reversal strategies, etc. This includes warfarin, direct thrombin inhibitors, antiplatelet agents, and also the use of antifibrinolytics which are valuable and recommended in cardiac surgery guidelines and also in trauma patients at high risk of hemorrhagic shock [137].

Immunologic disorders may contribute to surgical risk. Clinicians should seek relevant information about congenital and acquired immune deficiencies and mitigate risks as they associate with perioperative infections (and also wound healing).

Karamichalis et al. and Nathan et al. have extensively investigated the operative phase of care in congenital cardiac surgery and developed a technical performance score. The final technical performance score has the strongest association with patient outcomes [138–143]. Additional work with this technical performance concept should be developed in other technical, high-risk procedures to identify risk, learn, improve, and mitigate risk [143].

Growing evidence from TeamSTEPPS and other training programs suggest that surgical teams that train together, develop surgical leadership skills, and use briefing and debriefing can produce better outcomes [144, 145]. Neily et al. reviewed 182,409 surgical cases from 108 VHA facilities, using the VHA Surgical Quality Improvement Program (VASQIP) in years 2006–2008, and showed that briefings and debriefings in the operating room, surgical checklists and quarterly coaching interviews, led to a remarkable 18 % reduction in mortality compared with the year before and with non-training sites [146]. Furthermore, observation and feedback to surgical teams of effective teamwork in the operating room can identify substantive deficiencies in the system and conduct of procedures, even in otherwise successful operations, and lead to improvements in surgical team performance [147].

Many efforts have improved the quality, safety, and value of healthcare, thereby mitigating risk. Cardiac surgery mortality was reduced by 24 % by the prototypical learning collaborative, the New England Cardiovascular collaborative, and by 20 % in the Michigan surgical collaborative [148, 149]. Stamou et al. pioneered the use of a Quality Improvement Program (QIP) in cardiac surgery and witnessed a 40 % reduction in mortality, improved morbidity and process compliance, as well in leading key performance indicators such as early extubation [78, 79, 150–152]. Culig et al. utilized the Toyota Production System in a new program and found the risk-adjusted mortality was 61 % less than expected and the cost per case was also decreased by $3497 [153].

The Michigan Keystone Project collaboration targeted the critically ill, where Pronovost et al. demonstrated decreased catheter related bloodstream surgical infections (CLABSI) by 66 % [154, 155]. Others like Dixon-Woods have demonstrated greatly reduced benefits of CLABSI efforts when clinicians are not actively championing and privy to all change efforts [156]. Additional investigation in this area is aimed at understanding how to sustain the gains achieved and diffuse them across other clinical units [157]. More recent, US government sponsored efforts include Hospital Engagement Networks (HEN) and the Partnership for Patients (PfP) (https://​innovation.​cms.​gov/​Files/​reports/​PFPEvalProgRpt.​pdf.). Both HEN and PfP have demonstrated success in reducing some complications and cost savings although some question remains whether this approach actually improves care on the whole [158].

Geographic regionalization efforts in high risk, low incidence procedures such as head and neck surgery, cancer surgery, and pediatric cardiac surgery are noteworthy [159–161]. In Maryland, mortality from pancreaticoduodenectomy, LOS, and costs all appeared to be favorably impacted by regionalization [162, 163]. Birkmeyer et al. have studied the impact of volume on quality and suggest that in the USA, operative mortality with high-risk surgery has decreased [164]. Furthermore, market concentration increased and hospital volume have contributed to declining mortality with some high-risk cancer operations (pancreatectomy, cystectomy, and esophagectomy), but mortality reduction with other procedures (carotid endarterectomy, abdominal aortic aneurysm repair , coronary artery bypass, and aortic valve replacement) are largely attributable to other factors.

“Failure to rescue” (FTR) from complications, another form of risk to patients, was endorsed by NQF as a core quality measure in 2012 and is quantified for acute care facilities (https://​www.​qualityforum.​org/​News_​And_​Resources/​Press_​Releases/​2012/​NQF_​Endorses_​Surgical_​Measures.​aspx). The study of FTR has elucidated a 2.5 fold difference, variation in institutional procedural mortality, and strong correlation with FTR (range 6.8–16.7 %) [165]. Ferraris et al. utilized NSQIP data for nearly 2,000,000 patients and found that 20 % of the high-risk patients account for 90 % of FTR and two thirds of the FTR patients had multiple complications [166]. Elderly patients are at significant risk of FTR from pulmonary and infectious complications and differences are also witnessed between facilities competence in rescuing the elderly [167]. Considerable variation in FTR rates appear to be prominent in the highest risk patients, pointing to the need to identify high-risk patients [168]. Additional insight will accrue from the related pursuit of failure to arrest complications (FTAC) , by not limiting our analyses to deaths, but important complications.

Prager et al. demonstrated that the FTR rate in cardiac surgery was significantly better in the low mortality facilities for the majority of complications (11 of 17) with the most significant findings for cardiac arrest, dialysis, prolonged ventilation, and pneumonia. Furthermore, low mortality hospitals are found to have lower FTR rates [169]. Novick et al. also investigated FTR in the cardiac surgery population and found a 3.6 % mortality rate, complications in 16.8 % of patients, and 19.8 % FTR. FTR in patients with acute renal failure was 48.4 % while septicemia was 42.6 %. They recommend that FTR should be monitored as a quality-of-care metric, in addition to mortality and complication rates, and utilized to identify opportunities to improve quality and value [170]. FTR rates in lung surgery have also been found to be higher at high mortality hospitals [171].

A 10-year review of Medicare data, including 9,440,503 patients undergoing one of 12 major operations determined that the readmission to the index hospital was associated with 26 % lower 90-day mortality than when a patient was readmitted to a non-index facility [172]. Additionally, the effect was significant for all procedures, but most pronounced for hospital readmissions after pancreatectomy and aortobifemoral bypass [173]. This finding reinforces the risk mitigation potential for centralization of high-risk procedures.

The archetype risk prevention drug efficacy and safety is aprotinin. While utilized for years in cardiac surgery, and markedly reducing the risk of hemorrhage and transfusion, various studies ultimately led to discontinuation of its use [174]. Aprotinin has been linked with risk of myocardial infarction, cardiac arrest, heart failure, renal dysfunction, stroke, encephalopathy, and even long term survival [175]. A complete review of the risks and benefits of various pharmacologic agents is beyond the scope of this text, but each has a therapeutic index, small or wide, as well as favorable characteristics and various risks. Antibiotics are another example, having markedly reduced the risk of various infections, but increased use and abuse has led to the proliferation of drug resistant infections and maladies such as C. difficile colitis and Carbapenem-Resistant-Enterobacteriaceae.

Intraoperative transfusion of red blood cells and other blood products increases the risk of mortality and several types of morbidities in surgical patients [176]. This risk has been described in cancer surgery, cardiac surgery, and surgical critical care affecting both short and long term outcomes [177]. An NSQIP database interrogation related risk to a single unit appears after adjustment for transfusion propensity [177].

Early patient and family engagement has been utilized and incorporated into care for many years. For example, Ergina et al. believed in the merit of engagement and published the seminal investigation on preoperative patients with COPD [178]. They promoted appropriate perioperative strategies to mitigate risk, which included smoking cessation, education, exercise training, and weight reduction. Jones et al. demonstrated the value of education in joint replacement via improvement in LOS (without changing complications) [179]. Additional studies at proactive risk mitigation strategies include exercise and inspiratory muscle training [180–182]. Arora and colleagues have investigated the positive merits of combating the risk of frailty with 8 weeks of “prehabilitation” on 3 and 12 month outcomes [183, 184].

More expansive programs include surgical preparedness aimed at the continuum of care, or the “surgical home,” and detailed pathways developed to promote early recovery after surgery (ERAS) . ERAS protocols have been developed for gastrectomy, cystectomy, colonic and rectal surgery, and pancreaticoduodenectomy (http://​www.​erassociety.​org/​). ERAS protocols are proactive, including counseling, neuraxial anesthesia, avoidance of hypothermia, non-opioid oral analgesics, early mobilization, removal of urinary catheters, and challenge entrenched practices such as nasogastric tubes (See Chap. 23). The American Society of Anesthesiologists maintains standards, guidelines, and practice parameters for pre-anesthesia care, post-anesthesia, and perioperative care (http://​www.​asahq.​org/​quality-and-practice-management/​standards-and-guidelines).

Porter suggested altering the traditional structure of care into the integrated practice unit (IPU) . The IPU is a dedicated team comprised of both clinical and nonclinical personnel providing the full care cycle for the patient’s condition (https://​hbr.​org/​2013/​10/​the-strategy-that-will-fix-health-care). This model is similar to the clinical microsystem. Microsystems, based on work of intelligent enterprises by Quinn, apply systems thinking to organizational design and represent the smallest replicable organizational unit of change [185]. Microsystems are key to implementing effective strategy, leveraging information technology, and embedding other performance-enhancing practices into the service delivery process [186]. The evolving redesign of healthcare delivery around service lines mirrors that of “focus factories” (smaller number of offerings of high-quality products) in other industries [187]. This trend in value creation represents a migration away from “solution shops” (viz. traditional hospitals) creating considerable opportunities to optimize quality improvement activities.

Various methods have been used to promote the sharing mental of models, mitigating risk, and improving patient care. Most noteworthy are goal sheets, shown by Pronovost et al. to correlate with improved communication of goals and resulting in shorter ICU LOS [188]. Gawande et al. have shown reduced mortality and morbidity with checklist utilization [5, 189]. Patient hand-off tools have been utilized and been shown to reduce complications and readmissions to surgical ICU’s and back to hospitals [173, 190] and Quality Function Development (QFD) has been used to reduce waste and improved clinical support Managed Care Organizations [191].