Anaesthetic perioperative management of patients with pancreatic cancer 2

EVALUATION AND OPTIMISATION OF PREOPERATIVE PHYSICAL

CONDITIONS AND MEDICATIONS

A growing number of old patients benefits from a surgical procedure[19]. Age is an independent risk factor of postoperative mortality and postoperative complications and can cause a gradual progressive loss in the biological reserves for maintaining physiological homeostasis under stress.

In addition, an increasing number of patients present with one or more age-related chronic conditions, which further decrease their ability to respond to stress.

Cardiac and pulmonary diseases are the most frequently observed co-morbidities that anaesthetists and surgeons must manage during this complex surgery.

A complete history of prior medical and surgical conditions and a full medication list are particularly important[20,21].

CARDIOVASCULAR RISK EVALUATION:

Cardiovascular complications are among the most common and significant postoperative problems in elderly patients.

A practical guideline for perioperative cardiovascular evaluation for non-cardiac surgery has been proposed by the American College of Cardiology and American Heart Association Task Force[22].

Patients should be assessed using an approach that considers clinical predictors, the risk of the proposed operation and the functional capacity.

Ageing is accompanied by increased vascular and ventricular stiffness, diastolic dysfunction and an increased risk of heart failure[23].

Diastolic dysfunction even with a normal or supranormal ejection fraction might elicit a significant effect on the perioperative outcome and management of elderly patients[12].

Diastolic dysfunction might significantly affect perioperative haemodynamics, response to fluid shifts, anaesthetic drugs and other Perioperative medications.

Patients with cardiovascular diseases are sensitive to haemodynamic instability and often require increased filling pressures to generate an adequate cardiac output.

The anaesthetist must carefully manage fluids during the operation to avoid overload or rapid volume administration.

Moreover, the anaesthetist must maintain a normal haemoglobin value (Nair et al[24] demonstrated that anaemia was strongly associated with diastolic dysfunction in patients with coronary artery disease)

if possible, must choose volatile anaesthetics that appear to improve diastolic parameters (in contrast to propofol, which elicits the opposite effect) as measured by echocardiography[25].

Thoracic epidural analgesia should be strongly suggested, not only for pain management and for decreasing respiratory complications but also because its use appears to improve cardiac function by improving the diastolic characteristics of the left ventricle[26,27].

PROPHYLACTIC PERIOPERATIVE Β-BLOCKADE:

In general, cardiovascular medication should not be discontinued prior to surgery.

In the perioperative setting, β-blockers are not contraindicated in patients with diastolic heart failure and should be continued in patients with systolic heart failure.

However, caution is warranted with the acute administration of β-blockers in situations of decompensating systolic heart failure.

Nonetheless, given the risk of acute withdrawal, β-blockade in patients with coronary artery diseases or coronary artery disease risk factors should not be discontinued preoperatively.

Rather, perioperatively increasing the dosage of the patient’s β-blockade regimen would most likely be beneficial[28-30].

If a patient who is scheduled for elective pancreatic surgery requires a new prescription, it should be started at least 1 mo prior to the procedure to allow for dose adjustment[ 31,32].

PULMONARY RISK EVALUATION:

Pulmonary complications such as pneumonia, failure to wean, and postextubation respiratory failure represent the second most frequent types of postoperative complication following wound infection, with an estimated incidence rate ranging from 2.0% to 5.6% following surgery[33,34].

Pulmonary disease increases the risk of postoperative complications, accounting for 40% of postoperative complications and 20% of deaths[35].

Age-related changes, such as increased closing volumes and decreased expiratory flow rates can predispose older patients to pulmonary complications.

Some postoperative pulmonary complication (PPC) predictors after pancreatic surgery are summarised in Table 2 (modified from Canet et al[36]).

Identifying the patients who are at high risk for PPCs, can help the anaesthetist to design individually tailored management approaches[37-39].

Pharmacologic measures for managing these complications are either unavailable or limited, and as a result, treatments must be based on physical therapy and respiratory support ventilation.

Finally, the ability to predict PPCs would enable clinicians to give patients more precise risk assessments, thereby facilitating their decision making.

NUTRITIONAL STATUS AND MECHANICAL BOWEL PREPARATION

The prevalence of malnutrition is high in patients who are submitted for surgery and ranges from 35% to almost 60%[40].

Malnutrition has been consistently associated with impaired immunity[41] and can lead to increased complications, such as pressure ulcers, delayed wound healing, increased risk of infections, impaired muscular and respiratory functions[42], as well as increased mortality and poor clinical outcomes.

Nutritional status should be determined because nutritional deficiencies are common in patients who have undergone pancreatic resection for malignant tumours.

Because malnutrition is potentially reversible with appropriate nutritional support, the early identification of high-risk patients is crucial, and preoperative malnutrition screening is required to identify and to treat the malnutrition[ 43].

Recently, the routine screening of patients to iden-tify risk of malnutrition has been recommended by many national, international, and specialist organisations[44,45].

THE MALNUTRITION UNIVERSAL SCREENING TOOL (MUST) for adults was recently validated by several studies, which have demonstrated that as a screening procedure, MUST is rapid and easy to use[46,47].

The MUST appears to be a valid and easy screening tool for pancreatic surgery[20], which can identify patients at high risk for major complications and death.

Furthermore, the MUST can prompt the implementation of effective nutritional interventions to reduce poor outcomes and thereby optimise the use of postoperative critical care beds and hospital resources.

As soon as malnutrition is recognised, preoperative nutritional supplements should be provided when possible.

This supplementation can include high-energy foods, vitamins, enteral feedings, or, if necessary, total parenteral nutrition.

MECHANICAL BOWEL PREPARATION

“Enhanced recovery” or “FAST-TRACK” (FT) PROGRAMMES, which were first developed by Kehlet[48], are structured interdisciplinary strategies that have been introduced to optimise peri-operative care and to accelerate postoperative recovery[49].

A major intervention principle of this approach is the avoidance of preoperative MECHANICAL BOWEL PREPARATION (MBP), which has been employed as a preventative measure in gastrointestinal surgery for more than a century as an essential factor for avoiding infectious complications and anastomotic dehiscence.

FT programmes, which exclude MBP, have been proposed more often in other surgical fields (elective colorectal, gastro-oesophageal and aortic surgery) and rarely have been applied to liver and pancreatic surgery[50].

The application of MBP in this type of surgery has been evaluated by limited studies (a retrospective case-control study by the Jefferson University[51] and a review by Salvia et al[52]), which have shown that it did not improve Perioperative outcomes.

At our institution, MBP has been excluded from clinical practice in pancreatic surgery.

A recen review examined and compared the application of FT protocols with standard care in elective liver and pancreatic surgeries, showing that FT programmes can enhance post-operative recovery and reduce the length of hospital stays with no increase in adverse events, such as re-admissions, morbidity or mortality[53,54].

The avoidance of MBP, together with other measures including the application of epidural analgesia, the prevention of intra-operative hypothermia, fluid restriction, post-operative nutritional care and early mobilisation, collectively represent essential elements of a FT programme that is warranted for complex surgical operations such as pancreatic resection[55,56].

In our experience FT programmes for hepatopancreatic resections appear to be safe and associated with a reduction in the length of hospital stays.

RISK STRATIFICATION, RATIONALE FOR THROMBOPROPHYLAXIS,

AND RECOMMENDATIONS

In patients undergoing general and abdominal-pelvic surgery, the risk of venous thromboembolism (VTE) varies depending on both patient- and procedure-specific factors[57].

Pancreatic cancer is among the most common malignancies associated with thrombosis, as it occurs in 50% of total patients.

Prophylaxis against postoperative venous thromboembolism should be tailored to the patient’s level of risk.

A model (THE CAPRINI SCORE) that can potentially be used for such purposes estimates VTE risk by adding points for various VTE risk factors[59].

Pharmacological prophylaxis reduces the risk of pulmonary embolism by 75% in general surgical patients and by 57% in medical patients[60].

The use of low-molecularweight heparins (LMWHs) to prevent thrombotic events in these patients is a common and well-documented practice.

Current recommendations strongly advise effective and preventive strategies for all hospitalised patients who are defined as moderate to high risk for VTE and are awaiting pancreatic surgery.

LMWHs appear to be effective and are potentially associated with a lower risk of bleeding when the first dose is administered 12 h preoperatively

We recommend the administration of LMWH from the day prior to surgery to all patients scheduled for pancreatic cancer surgery.

In the case of patients who are receiving anticoagulants or antiplatelet therapy and require an elective surgery or procedure, the actual guidelines addressing their management are underlined in Table 3 and are modified from Douketis et al[62].

GUIDELINES ON THE PROPHYLAXIS OF VENOUS THROMBOEMBOLISM AND ANTIPLATELET AND ANTICOAGULANT MANAGEMENT ADJUSTED ACCORDING TO RECENT GUIDELINES

In patients receiving bridging anticoagulation with a therapeutic-dose Ⅳ of unfractionated heparin, treatment is recommended to be stopped no later than at 4 to 6 h prior to surgery

In patients receiving bridging anticoagulation with a therapeutic-dose of LMWH, the last preoperative dose of LMWH is recommended to be administered at approximately 24 h prior to surgery instead of at 12 h prior to surgery

In patients receiving bridging anticoagulation with a therapeutic-dose of LMWH and are undergoing high-bleeding-risk surgery, resumption of the therapeutic dose of LMWH is recommended at 48 to 72 h after surgery instead of within 24 h following surgery

In moderate-to-high-risk patients receiving acetylsalicylic acid who require non-cardiac surgery, treatment with acetylsalicylic acid is recommended to be continued around the time of surgery instead of discontinued at 7 to 10 d prior to surgery

In patients with a coronary stent who require surgery, deferment of surgery is recommended at 6 wk or 6 mo after the placement of a bare metal or drugeluting stent, respectively, instead of initiating surgery during these time periods

In patients requiring surgery within 6 wk or 6 mo of the placement of a bare-metal or drug-eluting stent, respectively, continuing perioperative

antiplatelet therapy is recommended instead of stopping therapy at 7 to 10 d prior to surgery