Preoperative Evaluation

PREOPERATIVE PREPARATION OF THE PATIENT Dr. Hiwa Omer Ahmed Assistant professor in General Surgery LECTUR 1 & 2

LECTURE 1 PREOPERATIVE PREPARATION OF THE PATIENT • convergence of the art and science of the surgical discipline. • in outpatient office visit to hospital inpatient

• Approaches to preoperative evaluation differ significantly, depending on the 1.nature of the complaint 2. the proposed surgical intervention 3. patient health 4. assessment of risk factors 5.the results of directed investigation 6. interventions to optimize the patient's overall status 7. readiness for surgery.

Determining the Need for Surgery confirmation of relevant physical findings and review of the clinical history and laboratory and investigative tests that support the diagnosis.

Perioperative Decision Making • Once the decision has been made to proceed with operative management, a number of considerations must be addressed regarding the 1.timing and site of surgery 2. the type of anesthesia 3. the preoperative preparation necessary to understand the patient's risk and optimize the outcome.

Preoperative Evaluation • The aim is to identify and quantify any comorbidity that may have an impact on the operative outcome. The goal is to uncover problem areas that may require further investigation or be amenable to preoperative optimization ..

• The preoperative evaluation is determined in light of the 1.planned procedure (low, medium, or high risk), 2. planned anesthetic technique, 3. the postoperative disposition of the patient (outpatient or inpatient, ward bed, or intensive care). 4. to identify patient risk factors for postoperative morbidity and mortality.

• consultation with an internist or medical subspecialist may be required to facilitate the workup and direct management. In this process, communication between the surgeon and consultants is essential to define realistic goals for this optimization process and to expedite surgical management

The aim of a preoperative evaluation to assess the fitness of the individual for anesthesia and surgery. A well-conducted history and physical examination answer several important questions:

• Is this a healthy patient? • What is the indication for surgery? • Is the surgical procedure low risk, intermediate risk, or high risk? • What is the functional status of the patient? • What is the effect of the present condition on the patient? • What improvement is expected after surgery?

Answers to these questions should then direct preoperative testing and management. 1.The tests selected should therefore evaluate existing illness, screen for conditions that could affect outcomes in the perioperative period, and help to determine perioperative risks. Existing illnesses that need evaluation and possible treatment include hypertension, diabetes mellitus, cardiac, vascular, pulmonary, renal, and hepatic diseases. The pregnant patient, the geriatric patient, the patient with oncologic disease, malnutrition, or coagulation disorders also needs directed evaluations

THE HEALTHY PATIENT The initial preoperative evaluation of a patient should be supplemented by a complete assessment of the patient’s general health. This involves a thorough *history *physical examination. 1.Complete blood counts

2.Blood urea and electrolytes

3.An electrocardiogram (ECG) is indicated over 40 years,.

4.Posteroanterior and lateral chest x-rays 5. Hb%

6.GUE

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The history should include information regarding any known medical problems and ongoing treatment, previous surgical procedures, and problems if any during previous anesthesia. These can include difficult intubation, bleeding tendencies, and anesthetic jaundice. • Family history of problems during anesthesia or surgery should be obtained. These can make the anesthesiologist aware of potential problems such as malignant hyperthermia, bleeding tendencies, or thrombophilia. • In addition to routine information about family history, a strong family history of allergies should alert the surgeon to the possibility of hypersensitivity to drugs.

• An exhaustive history of drug allergies, sensitivities, and current or recently taken medications should be obtained. Medications such as digitalis, insulin, and corticosteroids should be maintained and their doses carefully regulated in the perioperative period. • If the patient is on corticosteroids or if it has been discontinued within a month of surgery, he or she may have a hypofunctioning adrenal cortex resulting in impaired physiologic responseM to surgical stress

Consent for surgical treatment • • • •

Objectives Recognize the need to establish trust and confidence in patients under your care. Understand that a signature on a consent form is not legal proof that informed consent has been given. Realize that you must warn patients of the hazards as well as the benefits of surgical treatment. Identify and deal appropriately with difficulties in gaining consent. Respect the confidentiality of your dealings with patients.

THE MORAL IMPORTANCE OF INFORMED CONSENT

• • The moral unacceptability of anyone exercising unlimited power over others is at the heart of many of our liberal values.

What is informed consent? • to be able to make a considered choice about what is in their personal interests - they must receive sufficient accurate information about their illness, the proposed treatment and its prognosis.

DO & DONT

1. Describe the procedure itself, including information about its practical implications and probable prognosis. 2. Reveal the probability of specific associated risks or complications. 3. Do not assume that the patient already knows the risks of other aspects of the proposed surgical procedure, such as the complications that might result from a general anaesthetic, bed rest, intravenous fluids or a catheter. 4. Outline other surgical or medical alternatives to the proposed treatment, including non-treatment, along with their general advantages and disadvantages.

Good consenting practice 1. As much as possible, ensure that the physical surroundings during the discussion between you and your patient are conducive to easy, quiet conversation.

2. Use the simplest possible language, avoiding needless technicalities. Appropriate leaflets or booklets can be helpful, as is innovative work using audiorecording of interviews; patients can be encouraged to take the recording home to discuss with others.

3. Having attempted to provide clear information, now determine whether or not the patient has actually understood it.

The consent form • 1. In principle, the consent form signed by the patient before operation • You should also sign the form after obtaining consent to indicate that, to the best of your knowledge, the patient has both received and understands the information necessary to make a considered judgment.

2. However, it is unnecessary for a competent patient to sign for all surgical interventions. A simple investigative procedure such as venepuncture, involving minimal risk, can be undertaken after oral explanation of, and consent to, what it physically entails. Consent can be assumed to be implied if the patient then accepts the procedure. 3. The consent form is not legal proof that consent has been given. Always bear this in mind if you are tempted to cut corners as regards good practice in obtaining consent. It is merely one piece of evidence that some attempt was made to obtain informed consent, not that it was a morally or legally satisfactory attempt.

unconscious Here, there is a clear duty to treat, despite the fact that it is impossible to obtain the patient's consent, and there would be no risk of battery if operation proceeded. The only circumstance that justifies surgery without consent is the dramatic need of patients, coupled with their inability to give consent.

Children Ordinarily, obtain consent for elective surgery on young children from someone - usually the parent - deemed competent to make informed choices about the child's best interests. However, this does not suggest that you must always be guided solely by parental wishes. If you believe such a decision is necessary to save the child's life, the parents' wishes can be overridden. If there is time, apply to the court for the appropriate order. If not, you can still proceed.

LECTURE 2

Preoperative preparation for surgery

ROUTINE PREOPERATIVE PREPARATION Evaluation 1. Take a full history and exclude any significant medical problems 2. Check clinical signs against the planned surgical procedure, in particular noting the side involved. Confirm that the planned operative procedure is appropriate.

3. Take a full drug history with specific enquiry regarding allergic responses to drugs, latex and skin allergies. Continue medication over the perioperative period, especially drugs for hypertension, ischaemic heart disease and bronchodilators. Give patients on oral steroid therapy intravenous hydrocortisone. Stop oral warfarin anticoagulation 3 days preoperatively and check the prothombin time prior to surgery.

Patients taking aspirin or other antiplatelet medication (e.g. clopidogrel) may have an increased risk of bleeding; stop these drugs for at least 48 h preoperatively for major surgery.

Stop drugs, over the perioperative period, that may interfere with anaesthetic agents, including monoamine oxidase inhibitors, lithium, tricyclic antidepressants and phenothiazines. If possible, stop the oral contraceptive pill 4 weeks prior to any major surgery. Postmenopausal patients on hormone replacement therapy do not need to have their medication stopped before an operation.

4. There is a clear correlation between malnutrition in the preoperative period and an increased morbidity and mortality from surgery .

5. Young and fit patients undergoing minor procedures do not require any preoperative investigations In older patients or those with significant medical problems, standard investigation would include a full blood count, urea and electrolytes, chest X-ray and electrocardiogram.

Routine preoperative measures 1. Adhere to the protocol followed by your firm 2. Prohibit solid diet to adult patients for 6 h, and clear fluids for 4 h, prior to an elective general anaesthetic. Fasting times for children vary in different hospitals and they are also age dependent.

Babies under 1 year No breast milk for 2-3 h before anaesthesia No formula feed for 6 h before anaesthesia Clear fluids may be given up to 3 h before anaesthesia Children over 1 year No food/milk for 6 h before anaesthesia Clear fluids up to 3 h before anaesthesia 3. The operation site must be prepared by the removal of hair, if this is necessary for access, using a depilatory cream. Shaving or clipping hair from the operation site increases the risk of infection, unless the skin preparation is carried out immediately prior to surgery.

4.Mark a unilateral operation site on the skin with an indelible marker pen.

5. Explain to the patient (or guardian) the procedure and any likely complications, answer questions the patient may have, and only then have them sign the consent form. If you are unable to answer the patient's questions, seek help from a senior colleague.

6. It is good practice for the operating surgeon to obtain the patient's consent; not immediately before an operation but some time ahead, so that they may have a period of reflection, and an opportunity to ask further questions that may arise.

7. Antibiotic administration is guided by the surgical procedure involved and is discussed below, as is prophylaxis against deep vein thrombosis. 8. If specific services, such as frozen section histopathology or intraoperative radiography are likely to be required during the operation, organize these in advance.

9. PROPHYLAXIS AGAINST DEEP VEIN THROMBOSIS AND PULMONARY EMBOLI

Pulmonary emboli are a major cause of mortality for surgical patients, accounting for 10% of inpatient deaths in the United Kingdom. Recent operation, immobilization and trauma were responsible for 50% of deep vein thrombosis (DVT) in a review by Cogo et al (1994), but there are other important predisposing factors,

such as the high oestrogen content oral contraceptive pill, and significant obesity . Many risk factors cannot be avoided, but take measures to avoid propagation of any thrombosis: • Subcutaneous heparin may reduce the incidence of DVT by 50%; it is generally well tolerated Systemic anticoagulation effects of low dose subcutaneous heparin are minimal and haemostasis is not impaired. • Newer low molecular weight heparins (LMWHs), as effective as standard heparin, need only once a day dosage.

Risk factors for deep vein thrombosis • • • • • • • • •

Recent surgery Immobilization Trauma Oral contraceptive pill Obesity Heart failure Arteriopathy Cancer Age > 60 years

SYSTEMS APPROACH TO PREOPERATIVE EVALUATION • Cardiovascular • Cardiovascular disease is the leading cause of death in the industrialized world, and its contribution to perioperative mortality during noncardiac surgery is significant. • Consequently, much of the preoperative risk assessment and patient preparation centers on the cardiovascular system.

ASA classification •   I—Normal healthy patient   •   II—Patient with mild systemic disease   •   III—Patient with severe systemic disease that limits activity but is not incapacitating    • IV—Patient who has incapacitating disease that is a constant threat to life    • V—Moribund patient not expected to survive 24 hours with or without an operation

• The optimal timing of a surgical procedure after myocardial infarction (MI) is dependent on the duration of time since the event and assessment of the patient's risk for ischemia, either by clinical symptoms or by noninvasive study. Any patient can be evaluated as a surgical candidate after an acute MI (within 7 days of evaluation) or a recent MI (within 7-30 days of evaluation). The infarction event is considered a major clinical predictor in the context of ongoing risk for ischemia. The risk for reinfarction is generally considered low in the absence of such demonstrated risk. General recommendations are to wait 4 to 6 weeks after MI to perform elective surgery

Preoperative evaluation of pulmonary function • may be necessary for either thoracic or general surgical procedures. • Necessary tests include forced expiratory volume in 1 second (FEV1), forced vital capacity, and the diffusing capacity of carbon monoxide. Adults with an FEV1 of less than 0.8 L/sec, or 30% of predicted, have a high risk for complications and postoperative pulmonary insufficiency; nonsurgical solutions are sought. Pulmonary resections need to be planned so that the postoperative FEV1 is greater than 0.8 L/sec, or 30% of predicted..

• Preoperative interventions that may decrease postoperative pulmonary complications include 1.smoking cessation (>2 months before the planned procedure), 2.bronchodilator therapy, 3.antibiotic therapy for preexisting infection, 4.pretreatment of asthmatic patients with steroids. 5.Perioperative strategies include the use of a.epidural anesthesia, b. vigorous pulmonary toilet and rehabilitation, c. continued bronchodilator therapy

Renal • Approximately 5% of the adult population have some degree of renal dysfunction • . In fact, a preoperative creatinine level of 2.0 mg/dL or higher is an independent risk factor for cardiac complications.

• Patients with chronic end-stage renal disease undergo dialysis before

Hepatobiliary • . A patient with liver dysfunction requires careful assessment of the degree of functional impairment, as well as a coordinated effort to avoid additional insult in the perioperative period

• A patient with liver dysfunction undergoes standard liver function tests. • can be investigated by serologic testing for hepatitis A, B, and C. • Alcoholic hepatitis is suggested by lower transaminase levels and an aspartate/alanine transaminase ratio (AST/ALT) greater than 2.

Endocrine • A patient with an endocrine condition such as diabetes mellitus, hyperthyroidism or hypothyroidism, or adrenal insufficiency is subject to additional physiologic stress during surgery. • The preoperative evaluation identifies the type and degree of endocrine dysfunction to permit preoperative optimization.

DM • A diabetic patient requires special attention to optimize glycemic control perioperatively. • Non–insulin-dependent diabetics need to 1.discontinue long-acting sulfonylureas such as chlorpropamide and glyburide • 2.a shorter-acting agent or sliding-scale insulin coverage may be substituted in this period. • The use of metformin is stopped preoperatively because of its association with lacticacidosis in the setting of renal insufficiency.

• An insulin-dependent diabetic is told to withhold long-acting insulin preparations (Ultralente preparations) on the day of surgery; lower dosages of intermediate-acting insulin (NPH or Lente) are substituted on the morning of surgery. • These patients are scheduled for early morning surgery, when feasible. • During surgery, a standard 5% or 10% dextrose infusion is used with short-acting insulin or an insulin drip to maintain glycemic control. A patient with diabetes mellitus that is well controlled by diet or oral medication may not require insulin perioperatively, • but those with poorer control or patients taking insulin may require preoperative dosing and both glucose and insulin infusion during surgery

• Frequent assessments of glucose levels are continued through the postoperative period. Current recommendations are to maintain the perioperative glucose level between 80 and 150 mg/dL, even in patients not previously diagnosed as being diabetic. • Adequate hydration must be maintained with avoidance of hypovolemia. • Postoperative orders include frequent (every 2-4 hours) finger stick glucose checks and the use of short-acting insulin in the form of sliding-scale coverage

Immunologic • The approach to a patient with suspected immunosuppression is the same, regardless of whether this state results from antineoplastic drugs in a cancer patient or immunosuppressive therapy in a transplant patient or is the result of advanced disease in patients with acquired immunodeficiency syndrome. The goal is to optimize immunologic function before surgery and to minimize the risk for infection and wound breakdown. • Preoperative assessment includes a thorough history of the patient's underlying disease and current functional status; a history of immunosuppressive treatment, including names of medications and duration of treatment; and a history of recent changes in weight.

Hematologic • Hematologic assessment may lead to the identification of disorders such as anemia, inherited or acquired coagulopathy, or a hypercoagulable state. • Substantial morbidity may derive from failure to identify these abnormalities preoperatively. The need for perioperative prophylaxis for venous thromboembolism must be carefully reviewed in every surgical patient

• Anemia is the most common laboratory abnormality encountered in preoperative patients. It is often asymptomatic and can require further investigation to understand its cause

bleeding risk • All patients undergoing surgery are questioned to assess their bleeding risk. • . The inquiry begins with direct questioning about a personal or family history of abnormal bleeding. Supporting information includes a history of easy bruising or abnormal bleeding associated with minor procedures or injury. A history of liver or kidney dysfunction or recent common bile duct obstruction needs to be elicited, as well as an assessment of nutritional status. Medications are carefully reviewed, and the use of anticoagulants, salicylates, nonsteroidal anti-inflammatory drugs (NSAIDs), and antiplatelet drugs are noted.

• Physical examination may reveal bruising, petechiae, or signs of liver dysfunction. Patients with thrombocytopenia may have qualitative or quantitative defects as a result of immunerelated disease, infection, drugs, or liver or kidney dysfunction. Qualitative defects may respond to medical management of the underlying disease process, whereas quantitative defects may require platelet transfusion when counts are less than 50,000 in a patient at risk for bleeding

• Although coagulation studies are not routinely ordered, patients with a history suggestive of coagulopathy undergo coagulation studies before surgery. Coagulation studies are also obtained before the procedure if considerable bleeding is anticipated or any significant bleeding would be catastrophic. Patients with documented disorders of coagulation may require perioperative management of factor deficiencies, often in consultation with a hematologist.

Special preparations

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