More elderly patients

The number of elderly patients undergoing day surgery increases. A positive result of this trend is that avoidance of hospitalization and change in environment reduces the risk of postoperative cognitive impairment. However, further effort to evaluate the outcome of day surgery in the growing elderly population is warranted. Alternatively, the experience from cataract surgery in office-based or day-surgery practice is most reassuring and has gained wide acceptance as a cost-effective approach with high patient satisfaction.

Elderly patients are also, in increasing numbers, scheduled for day surgery that requires general anesthesia. The elderly are prone to have somewhat more minor perioperative cardiovascular events, the most frequent being hypertension and dysrhythmias. Hypotension and hypovolemia are relatively less frequent in this patient group compared with patients of all ages; hypotension constitutes about one-tenth of all cardiovascular events seen.[5]

Preoperative fasting routines

One important part of patient care is proper preparation with regard to intake of food and fluid in order to minimize the risk of regurgitation and aspiration in conjunction with the anesthesia.

Many countries have adopted revised fasting guidelines that allow patients without risk factors to eat a light meal up to 6 hours and to ingest clear fluids up to 2 hours prior to the induction of anesthesia.[6] The safety of a more liberal fasting regime in patients without obvious risk factors for delayed gastric emptying receives support from a recent Cochrane systematic meta-analysis review.[7] The acceptable safety of intake of clear fluid up to 2 hours prior to surgery has also been shown in obese patients and in children.[8–10]

Avoiding prolonged fasting and fluid restriction has beneficial effects on patient satisfaction, and may also have positive effects on outcome, reduced fatigue, postoperative nausea and vomiting (PONV), and glucose intolerance.[11]

Adherence to the new more physiological fasting guidelines is not yet well adopted. For simplicity, it may be easier to inform a patient not to take food or fluids after midnight.

Elective day-case surgery should allow proper planning and timing and, thus, information about intake of clear fluids up to 2–3 hours prior to anesthesia should be promoted in patients without risk factors. Shortening the preoperative fasting and promoting intake of clear liquid for up to 2 hours prior to anesthesia is today considered to be well established and evidence-based.

The authors’ conclusion in the Cochrane meta-analysis is clear; there was no evidence to suggest that a shortened fluid fast results in an increased risk of aspiration, regurgitation, or related morbidity compared with the standard “nil by mouth from midnight” fasting policy. Permitting patients to drink water preoperatively resulted in significantly smaller gastric volumes.

Clinicians should be encouraged to appraise this evidence for themselves and, when necessary, adjust any remaining standard fasting policies (nil-by-mouth from midnight) for patients who are not considered “at risk” during anesthesia.[7]

Preoperative nutrition: correction of deficits

Correction of malnutrition and specific nutritional or vitamin deficits should always be assessed before elective surgery and, as far as possible, substituted. The typical day-surgery patients are rarely those exhibiting a more extensive degree of malnourishment but, if present, it should be handled in accordance with general nutritional routines.

Preoperative testing of the clinically healthy patient has been questioned in recent years.[12] Patients showing signs or symptoms of being malnourished should be identified and possibly supported in order to restore proper nutritional status before surgery. Likewise, in patients with severe obesity, proper preoperative diet preparations have become standard care in most bariatric centers. Fluid deficits, low plasma/blood volume, and/or a low hematocrit should be evaluated and corrected whenever there are any signs, symptoms, or history raising suspicion about its occurrence.

Preoperative nutrition: “energy loading”

There are reports from studies evaluating the effects of preoperative nutritive fluid intake suggesting potential benefits without risk.[13] An increasing amount of evidence indicates that instead of being operated on in the traditional overnight fasted state, undergoing surgery in the carbohydrate-fed state has many clinical benefits. Many of these clinical effects can be related to the reduced postoperative insulin resistance by preoperative carbohydrate loading.

In many centers, preoperative carbohydrates have become established for use before major surgery. Those who advocate preoperative energy support suggest that carbohydrate loading should be considered for all patients who are scheduled for elective surgery and are allowed to drink clear fluid.[14] The value of such efforts in minor intermediate elective day surgery in ASA 1–2 patients may be debated.

Perioperative fluid therapy: anesthetic considerations

Perioperative fluid therapy in day surgery should be instituted on the basis of the case profile.

The benefit of fluid therapy can be questioned in minor surgical procedures of short duration (less than 15–20 min) and without any substantial fluid losses during the procedure.

Fluid therapy is more clearly beneficial in intermediate surgery, and administration of more liberal volumes probably leads to better recovery compared with lower volumes. Study design, fluid administered, and variables used for evaluation of effects vary between studies, and thus it is hard to provide clear, explicit guidelines (Table 20.1). The administered fluid has, in most studies, consisted of crystalloid fluid solutions such as lactated Ringer’s solution.

Administration of about 1 liter of isotonic electrolyte solution to compensate for the fasting, and a further 1 liter during surgery seems to improve the postoperative course of laparoscopic cholecystectomy. The group of Holte et al. has conducted several studies of the effects of perioperative fluid on outcome. They showed that administration of 30–40 ml/kg compared with 10–15 ml/kg lactated Ringer’s solution for laparoscopic cholecystectomy improves recovery of organ functions and reduces hospital stay.[15] In contrast, a benefit from using a liberal fluid regime during thyroid surgery was not supported in a study of similar design.[16]

Administration of crystalloids i.v. has been shown to influence the occurrence of PONV. Apfel et al. found in a quantitative review that a more liberal use of crystalloid infusion reduced nausea and need for rescue antiemetics, supporting a liberal approach in day-case patients without history of cardiac disease.[17]

The effects of high volume (30–40 ml/kg) perioperatively should also be put into perspective. Infusion of 40 ml/kg of lactated Ringer’s solution in volunteers with a mean age of 63 years decreased pulmonary function for 8 hours and also resulted in a significant weight gain that lasted for 24 hours [18]. Therefore, a more restricted fluid therapy should be adopted in the elderly. The risk of reduced lung function and edema must be acknowledged in the elderly, and fluid volume be adjusted accordingly.

Large volumes of crystalloid and colloid fluid have been compared in one study showing no difference in outcome with regard to the variables studied.[19]

The independent effect of adding glucose to the infused fluid has been studied by McCaul et al.[20] They could see no major benefit in adding glucose, which rather increased thirst and the incidence of pain besides elevating the blood glucose concentration.

The expansion of day-case surgery is moving rapidly, and there are reports of successful bariatric surgery performed on an ambulatory basis. Some institutions perform transurethral prostatectomy in day-case practice. The fluid management for these special procedures is addressed in other chapters. Procedure-specific fluid protocols should be used regardless of whether the patient is operated on in ambulatory practice or as an in-patient.