For centuries the surgeon’s chief training was in anatomy, almost to the exclusion of other aspects of the art. Only in the 20th century did the increasing scope of surgery and unremitting efforts to reduce the number of deaths and complications to a minimum lead inevitably to the realization that a sound understanding of physiology is as important as a thorough grounding in anatomic relationships. In the 21st century, there is increasing interest in evidence-based preoperative and postoperative care and the application of scientific knowledge and compassion to restore the patient to a normal physiologic state and equilibrium as readily as possible after minor or major surgery. The discipline of surgical critical care represents the ultimate merging of the art of surgery with the science of physiology.

The surgeon of the 21st century is concerned not only with the proper preoperative preparation of the patient and technical conduct of an operative procedure but also with the preparation of the operating room and an understanding of the problems created by illness in the patient as a whole. Because of the complexities of a patient population with many medical comorbid conditions, preoperative preparation may require a team approach. It is important for the surgeon to understand potential complications and their prevention and recognition. In the ideal situation, the preoperative preparation of the patient begins the ambulatory setting prior to admission. The surgeon assesses the patient and determines the need for surgery for the specific diagnosis. The surgeon advises the patient on the benefits and risks of the procedure in general as well as those that are specific to the operation being recommended. Informed consent is more than a signature on a piece of paper: it is a process of discussion and a dialogue between the surgeon and patient in which the patient has the opportunity to ask questions. The surgeon should also include a discussion of the possible use of blood products, and if deemed appropriate, advise the patient about autologous blood donation. In assessing the patient’s condition it is important to identify major health issues. Pulmonary pathology including chronic obstructive pulmonary disease and asthma should be identified. Any departure from the norm disclosed by the history, physical examination, or the various procedures enumerated below may call for further specialty referral and treatment in concert with the patient’s primary physician. Likewise, history of a myocardial infarction, valvular heart disease, or a previous coronary intervention may suggest the need for cardiac clearance and assessment by a cardiologist. Finally most patients undergoing major procedures are seen prior to surgery by an anesthesiologist. This is especially important if they are class III or IV according to the American Society of Anesthesiologist (ASA). Written or verbal communication with the referring physician and primary care physician is important in order to facilitate continuity of care.

In many situations, the primary care physician may be engaged to help ready the patient for surgery. The primary physician may then set in motion diagnostic and therapeutic maneuvers that improve control of the patient’s diseases, thus optimizing his or her status for anesthesia and surgery. Even simple “oral and respiratory prophylaxis,” for example, the ordering of dental care and treatment of chronic sinusitis or chronic bronchitis, can be beneficial. Restriction of smoking combined with expectorants for a few days may alleviate the chronic productive cough that is so likely to lead to serious pulmonary complications. The surgeon should supervise any special diets that may be required, apprise the family and patient of the special requirements, and instill in the patient that peace of mind and confidence which constitutes the so-called psychologic preparation. The patient should inform the surgeon of any food or drug idiosyncrasies, thus corroborating and supplementing the surgeon’s own observations concerning the patient as an operative risk.

It is helpful to require the patient to cough to determine whether his or her cough is dry or productive. In the presence of the latter, consultation with pulmonary medicine may be helpful and surgery may be delayed for the improvement that will follow discontinuance of smoking and the institution of repeated daily pulmonary physical therapy and incentive spirometry in addition to expectorants and bronchodilating drugs as indicated. In the more serious cases, the patient’s progress should be documented with formal pulmonary function tests, including arterial blood gases. Patients with other chronic lung problems should be evaluated in a similar manner.

In general, electrocardiograms are routinely obtained, especially after the age of 50. A stress test, radionuclide imaging scan, or ultrasound echo test may be useful for screening, while coronary angiogram, carotid Doppler ultrasounds, or abdominal vascular scans may be performed if significant vascular disease is present or requires correction before an elective general surgery operation.

Standard preoperative considerations include antibiotic prophylaxis and preventive measures for venous thromboembolism. In addition, some surgeons have the patient bathe with antiseptic soap the day prior to the operation. If any special diet or bowel preparation is necessary, the patient is so advised and given the necessary instructions or prescriptions. Intravenous antibiotics should be ordered to be administered within 1 hour prior to the incision. Some antibiotics have specific administration requirements. The surgeon may consult with the hospital pharmacy concerning the optimal timing of antibiotic administration for vancomycin, gentamicin, or other less commonly employed antibiotic preparations.

Hospitalized patients are frequently more ill than those seen in an ambulatory setting. In this setting, the surgical team works with the medical team to bring the patient into physiologic balance prior to surgery. Recommendations of pulmonary and cardiac consultants should be followed to improve the patient’s risk for surgery. The hospitalized patient may be separated from his or her family and may be depressed or have anxiety. The surgeon’s reassurance and confident manner can help the patient overcome some of the psychologic stress of illness.

Particularly for the hospitalized patient, assessment of nutritional status with measurement of albumin and prealbumin or other markers, pulmonary and cardiac function is necessary. If the patient is malnourished, then this should optimally be corrected prior to surgical intervention if the condition permits. Enteral feedings are preferred. In some cases with oropharyngeal obstruction, a percutaneous endoscopic gastrostomy may be performed to provide access. Feeding with prepared formulas may be necessary. If gastrointestinal access cannot be obtained, total parenteral nutrition (TPN) may be necessary. Although about 1 g of protein per kilogram of body weight is the average daily requirement of the healthy adult, it is frequently necessary to double this figure to achieve a positive nitrogen balance and protect the tissues from the strain of a surgical procedure and long anesthesia. The administered protein may not be assimilated as such unless the total caloric intake is maintained well above basal requirements. If calories are not supplied from sugars and fat, the ingested protein will be consumed by the body like sugar for its energy value.

If for any reason the patient cannot be fed via the gastrointestinal tract, parenteral feedings must be utilized. On occasion, a deficient oral intake should be supplemented by parenteral feedings to ensure a daily desirable minimal level of 1,500 calories. Water, glucose, salt, vitamins, amino acids, trace minerals, and intravenous fats are the elements of these feedings. Accurate records of intake and output are indispensable. Frequent checks on the liver, renal, and marrow functions along with blood levels of protein, albumin, blood urea nitrogen, prothrombin, and hemoglobin are essential to gauge the effectiveness of the treatment. One must be careful to avoid giving too much salt. The average adult will require no more than 500 mL of normal saline each day unless there is an abnormal loss of chlorides by gastrointestinal suction or fistula. Body weight should be determined daily in patients receiving intravenous fluids. Since each liter of water weighs approximately 1 kg, marked fluctuations in weight can give warning of either edema or dehydration. A stable body weight indicates good water and calorie replacement.

In catabolic states of negative nitrogen balance and inadequate calorie intake, usually due to the inability to eat enough or to a disrupted gastrointestinal tract, intravenous TPN using a central venous catheter can be lifesaving. Ordinarily, a subclavian or jugular catheter site is used. At present, these solutions contain a mixture of amino acids as a protein source and carbohydrates for calories. Fat emulsions provide more calories (9 calories per gram versus 4 for carbohydrates or protein) and lessen the problems of hyperglycemia. In general, the TPN solutions contain 20% to 25% carbohydrate as glucose plus 50 g of protein source per liter. To this are added the usual electrolytes plus calcium, magnesium, phosphates, trace elements, and multiple vitamins, especially vitamins C and K. Such a solution offers 1,000 calories per liter and the usual adult receives 3 L per day. This provides 3,000 calories, 150 g of protein, and a mild surplus of water for urinary, insensible, and other water losses. Any component of the TPN solution can be given in insufficient or excessive quantities, thus requiring careful monitoring. This should include daily weights, intake and output balances, urinalysis for sugar spillage, serum electrolytes, blood sugar and phosphate, hematocrit, and liver function tests with prothrombin levels in specific instances. Other than catheter-related problems, major complications include hyperglycemia with glucosuria (solute diuresis) and hyperglycemic nonketotic acidosis from overly rapid infusion. Reactive hypoglycemia or hypophosphatemia (refeeding syndrome) may occur after sudden discontinuance of the infusion (catheter accident).

Another major complication involves infection, and strict precautions are needed in preparing the solutions and handling the infusion bottles, lines, and catheters in order to prevent related blood stream infections. Guidelines from the CDC for the prevention of catheter-related blood stream infections should be followed. Prior to insertion standard hand hygiene procedures are followed. During insertion maximal sterile barrier precautions are employed. The skin is prepared with a >0.5% chlorhexidine preparation. If there is a contraindication to chlorhexidine then tincture of iodine, an iodophor or 70% alcohol can be used as alternatives prior to catheter insertion or with dressing changes. The dressing used to cover the central venous catheter is with sterile gauze, or sterile transparent, semipermeable dressing. Topical antibiotic ointment is avoided, except for dialysis catheters, because the potential to promote fungal infection and antimicrobial resistance. The catheter is replaced if the dressing becomes damp, loosened, or visibly soiled. In the adult, for short-term use central venous catheters gauze dressings are replaced every 2 days and for transparent dressings every 7 days. The same guidelines apply to children unless there is risk of catheter dislodgement which may be considered. There is evidence that central venous lines should be routinely replaced in order to avoid related bold stream infections. If the patient is not receiving blood products or fat emulsions, administration sets that are used continuously, including secondary sets and add-on devices should be changed no more frequently than at 96-hour intervals, but at least every 7 days. Fungemia or gram-negative septicemia should be guarded against, and ideally the catheter system should not be violated for drawing blood samples or for infusion of other solutions. Sepsis does not contraindicate the use of intravenous nutrition, but chronic septicemia without obvious etiology is the indication for removal and culturing of these catheters.

Vitamins are not routinely required by patients who have been on a good diet and who enter the hospital for an elective surgical procedure. Vitamin C is the one vitamin usually requiring early replacement, since only a limited supply can be stored in the body at any one time. In some instances (severe burns are one example), massive doses of 1 g daily may be needed. Vitamin B complex is advantageously given daily. Vitamin K is indicated if the prothrombin time is elevated. This should be suspected whenever the normal formation of vitamin K in the bowel is interfered with by gastric suction, jaundice, the oral administration of broad-spectrum antibiotics, starvation, or prolonged intravenous alimentation. Objective evidence of improved nutrition may be documented with rising serum protein concentrations, especially albumin, prealbumin, and transferrin, or with the return of a positive skin test for immunocompetence. Certainly if the patient’s condition requires urgent treatment, surgery should not be delayed to correct preoperative malnutrition, and the surgeon should plan methods of postoperative nutrition including the possible placement of a feeding jejunostomy or planning on TPN.

Blood transfusions may be needed to correct severe anemia or to replace deficits in circulating blood volume. Properly spaced preoperative transfusions can do more to improve the tolerance for major surgery in poor-risk patients than any other measure in preparation. Blood should be given if the patient is anemic. Such deficits have often been found even when the hemoglobin and hematocrit are normal, as they will be when both plasma volume and red cell volume are contracted concurrently. This situation has been dramatically termed “chronic shock,” since all the normal defenses against shock are hard at work to maintain the appearance of physiologic equilibrium in the preoperative period. If the unsuspecting surgeon fails to uncover the recent weight loss and, trusting the hemoglobin, permits the patient to be anesthetized with a depleted blood volume, vasoconstriction is lost and vascular collapse may promptly ensue. The hemoglobin level should be brought to approximately 10 g/dL or the hematocrit to 30% before elective surgery in which a significant blood loss is anticipated or if the patient has limited cardiopulmonary reserve.

Time for the restoration of blood volume and caution are both necessary, especially in older people. If the initial hemoglobin is very low, the plasma volume must be overexpanded. Packed red cells are specifically needed rather than whole blood. Each 500 mL of blood contains 1 g of salt in its anticoagulant. As a result, cardiac patients may have some difficulty with multiple transfusions from the salt or plasma loading, and diuretics can be very helpful. There has also been some concern about the potassium in blood stored a week or more. This should never prevent a needed transfusion, but it is a consideration in massive transfusions in emergency situations.

Patients requiring treatment for acute disturbances of the blood, plasma, or electrolyte equilibrium present a somewhat different problem. Immediate replacement is in order, preferably with a solution that approximates the substances being lost. In shock from hemorrhage, replacement should be made with electrolyte solutions plus blood, although plasma substitutes, such as dextran or hydroxyethyl starch solutions, can provide emergency aid in limited amounts (up to 1,000 mL) until blood or plasma is available. In severe burns, plasma, blood, and normal saline or lactated Ringer’s solution are in order. In vomiting, diarrhea, and dehydration, water and electrolytes will often suffice. In many of these patients, however, there is a loss of plasma that is easy to overlook. For instance, in peritonitis, intestinal obstruction, acute pancreatitis, and other states in which large internal surfaces become inflamed, much plasma-rich exudate may be lost, with no external sign to warn the surgeon until the pulse or blood pressure becomes seriously disturbed. Such internal shifts of fluid have been called “third space” losses. These losses may require albumin plus electrolyte solutions for proper replacement. It is because of these internal losses that many cases of peritonitis or bowel obstruction may require colloid replacement during their preoperative preparation.

In all such acute imbalances, a minimum of laboratory determinations will include serum or plasma sodium, potassium, chloride, bicarbonate, glucose, and urea nitrogen. Calcium, magnesium, and liver function tests may be useful, while arterial blood gases with pH, bicarbonate concentration Po₂ and Pco₂ enable accurate and repeated evaluation of the respiratory and metabolic components involved in an acidosis or alkalosis. Systemic causes of metabolic acidosis or alkalosis must be corrected. In either case, potassium may be needed. It should be given in sufficient quantity to maintain a normal serum level but only after the urine output is adequate to excrete any excess. Although the laboratory data are useful, the key to adequate replacement therapy is found in the patient’s clinical course and in his or her intake–output record. Evidence of restoration is found in a clearing mentation, a stable blood pressure, a falling pulse rate and temperature curve, improved skin turgor, and an increase in urine output.