Patients’ comorbidities are one of the main determinants of postoperative complications. In the preoperative period, the aim of perioperative medicine is to assess preoperative risk and optimize functional reserve and preoperative conditions that delay surgical recovery and increase the risk of morbidity and mortality. Ideally, once high-risk patients have been identified, multidisciplinary meeting should discuss the efficacy of alternative treatments to surgery to avoid the occurrence of surgical adverse events without affecting patients’ care [13]. If surgery remains the best treatment, preoperative strategies to optimize patients’ comorbidities should be adopted to minimize adverse outcomes [13].

In the preoperative phase physicians should alsotake the opportunity to commence lifestyle changes by supporting adolescent or adult patients with smoking and alcohol cessation programs,improve nutritional status and functional capacity. Recovering from surgery takes longer than expected. Even in absence of surgical complications, physiological and functional capacities are reduced by 20–40 % after surgery and take time to return to baseline values. Surprisingly, even following a relatively invasive surgical procedure such as ambulatory laparoscopic cholecystectomy, more than 50 % of patients do not recover to baseline activity levels 1 month after surgery [14]. Pre-habilitation programs aim at improving functional capacity and physiologic reserve before surgery and are becoming popular and effective preoperative strategies to help adult patients recover faster from surgery [15–17]. They include preoperative multimodal interventions such exercise training, nutrition supplement, and relaxation techniques for a period of 3–4 weeks, and they have demonstrated to be more effective than rehabilitation programs intervening only in the postoperative phase [18]. Although pre-habilitation programs enhance functional exercise capacity and reduce hospital stay, it remains unclear if they positively affect clinical outcomes [17].

Postoperative care of surgical patients is essential to ensure adequate surgical recovery. Determining the intensity of postoperative care is pivotal as early recognition and treatment of postoperative complications has been shown to significantly reduce surgical mortality [5]. The intensity of postoperative care should be determined considering patient’s preoperative risk and the invasiveness of the surgery. Admission to intensive care units or high dependency units should be reserved for high-risk patients or for complicated surgeries.

Postoperative acute pain management must ensure optimal analgesia, minimizing opioid side effects and facilitating early mobilization. The introduction of acute pain services has facilitated the management of surgical patients with inadequate pain control or with adverse events related to common analgesia techniques. It has also improved patients’ satisfaction and accelerated hospital discharge. The use of ultrasound-guided regional analgesia techniques for inpatients and outpatients has increased and successfully improved postoperative pain control. Indeed, also ambulatory patients can be comfortably and safely discharged home with continuous peripheral nerve blocks.

Perioperative hemodynamic management is essential to guarantee optimal organ perfusion and oxygen delivery. The use of cardiac output monitoring was typically limited in cardiac patients during the intraoperative and postoperative period or for critically ill patients admitted to intensive care units. Recently, the widespread use of perioperative echocardiography and noninvasive cardiac output monitors outside the operating room has gained popularity even in patients undergoing noncardiac surgery. Thanks to these devices physicians can now administer intravenous fluids based on more objective and accurate measures of hypovolemia, facilitating the hemodynamic management of high-risk surgical patients [21] and hemodynamically unstable patients [3]. In the perioperative period, echocardiography can also be utilized as diagnostic tool, for example, to identify preoperative cardiopulmonary conditions that can influence the management of surgical patients.

The use of ultrasound in the perioperative period is gaining popularity also to mange patients without cardiac conditions. For example, ultrasound-guided peripheral nerve blocks are considered standard of care in many institutions; bedsides, ultrasound of the lungs guides physicians to promptly diagnose and treat postoperative respiratory complications such as pulmonary edema, lung consolidation, pleural effusion, and pneumothorax [22]; ultrasound assessment of the gastric content provides important information about the individual risk of aspiration before the induction of anesthesia [23–26].

Chronic postsurgical pain (CPSP) can affect a significant proportion of surgical patients even following minor surgical procedures. Although the incidence of CPSP is higher after certain surgeries than others, uncontrolled severe acute surgical pain represents one of the main risk factors associated with the development of CPSP [27]. Identification of patients at higher risk of CPSP, nerve-sparing surgical techniques, and prevention and treatment of acute postoperative pain represent perioperative interventions that must be considered in every surgical patient to decrease the occurrence of this physically, mentally, and socially disabling condition [28].

Figure 1.2 summarized the most important areas of perioperative medicine discussed in this section.