Anesthesiology

Appendectomy - Procedures

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What the Anesthesiologist Should Know before the Operative Procedure

Appendectomy is the surgical removal of the appendix to treat appendicitis. The surgery can often be done using laparoscopic appendectomy or open appendectomy. General anesthesia is commonly used in both procedures.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Delay of the surgery may lead to life-threatening complications, such as ruptured appendix, peritonitis, and sepsis.

Emergent: Ruptured appendix and peritonitis represents a common surgical emergency and generally requires prompt removal of the appendix and a cleaning out of the abdominal cavity. This usually involved a major, open appendectomy surgery, and percutaneous drainage.

Urgent: Acute appendicitis with appendiceal abscess or phlegmon is considered an urgent surgery. It is associated with a high rate of complications. If the appendix ruptures, more intensive treatment and longer hospitalization are necessary.

Elective: Mild to moderately severe appendicitis is unlikely to be associated with major perforation of the appendix and complications; it often resolves with antibiotics alone or with elective appendectomy.

2. Preoperative evaluation

The history, physical examination, and laboratory evaluation should be completed prior to the day of operation. Given the nature of laparoscopic approach with insufflation of the abdomen, marked cardiopulmonary changes involves increased systemic vascular resistance, decreased venous return, increased V/Q mismatch, and reduced FRC.

Medically unstable conditions warranting further evaluation include unstable angina, coronary artery disease, signs of myocardial infarction, symptomatic arrhythmias, poorly controlled hypertension (diastolic >110, systolic >160), history of congestive heart failure, and history of chronic respiratory distress requiring home oxygen or chronic medication or with acute exacerbation and progression within past 6 months.

Delaying surgery may be indicated if the patient has unstable coronary and pulmonary conditions, particularly in the elderly; thorough cardiac evaluation should be performed before surgery.

3. What are the implications of co-existing disease on perioperative care?

Perioperative evaluation

Unless an emergency appendectomy is necessary, which requires surgery regardless of cardiac risk but still requires that cardiac risk factors be managed postoperatively, a careful cardiac evaluation should be made preoperatively. Patients' preoperative risk factors and the risks associated with the planned surgery (open or laparoscopic appendectomy) should be assessed. The ACC/AHA guideline advocates an approach that considers major, intermediate, and minor predictors of increased preoperative cardiovascular risk. If a major risk predictor is present, nonemergency surgery should be delayed for medical management, risk factor modification, and possible coronary angiography.

Perioperative risk reduction strategies

Monitoring: Most of patients only need ASA standard monitoring unless suspected severe cardiac disease exists; then invasive monitoring including arterial, central venous, and pulmonary artery catheters should be considered. Foley catheter is typically needed to decompress the urinary bladder, allowing safe placement of trocars if laparoscopic appendectomy performed.

Goals: Prevention/treatment of intraoperative cardiac ischemia by maximizing cardiac oxygen supply and minimizing cardiac oxygen demand.

Increase supply

  • Increase inspired oxygen concentration to increase oxygen content and correct anemia to increase oxygen-carrying capacity. Consider 100% FiO2 and blood transfusion.

  • Avoid severe bradycardia and tachycardia to ensure adequate coronary perfusion pressure. Consider appropriate medication with beta blockers, calcium channel blockers, and anxiolytics.

  • Raise the diastolic arterial pressure and decrease left ventricular end-diastolic pressure (LVEDP) to optimize coronary perfusion pressure gradients. Consider nitroglycerin to maintain optimal filling pressures with pulmonary artery catheter monitoring as needed.

  • Regulate metabolic status to maximize coronary artery diameter, which changes in coronary artery tone. Consider to monitor artery blood gas.

Decrease demand

  • Reduce heart rate to decrease oxygen consumption and increases diastolic filling time, thereby optimizing coronary vascular perfusion.

  • Reduce myocardial wall tension to optimize preload and afterload, and prevent excessive myocardial oxygen demand.

  • Attenuate myocardial contractility to diminish excessive myocardial demand. Positive inotropic drugs should not be used unless needed to increase contractility since these agents increase myocardial oxygen demand and thus might promote an ischemic state. With left ventricular heart failure, inotropic support may improve the relationship between oxygen supply and demand.

b. Cardiovascular system

Acute/unstable conditions: It is essential to identify the presence of pre-existing manifested cardiopulmonary disease, and to define disease severity, stability, and prior treatment. Any symptoms of cardio-pulmonary compromise may delay the operation and require further testing or intervention. Life-threatening conditions, such as ruptured appendix and septic, would warrant proceeding without further evaluation.

Baseline coronary artery disease or cardiac dysfunction—goals of management: According to the ACC/AHA guidelines, appendectomy falls into minimal to moderately invasive procedure; further workup is usually not recommended unless for the patients with symptomatic coronary artery disease (e.g., unstable angina, recent MI, and poorly controlled heart failure). It is important to perform a thorough cardiac evaluation (e.g., stress testing, coronary angiography) and optimize patients' medical conditions before surgery for nonemergency cases, given the effect of pneumoperitoneum if performed via the laparoscopic approach.

c. Pulmonary

Reactive airway disease (asthma)

Perioperative evaluation

Asthma increases the risk of bronchospasm, hypoxemia, hypercapnia, inadequate cough, atelectasis, and pulmonary infection following surgery. Optimal asthma control should be obtained. Patients with asthma should have an evaluation before surgery that includes a review of symptoms, medication use (particularly the use of systemic corticosteroids for longer than 2 weeks in the past 6 months), and measurement of pulmonary function.

Perioperative risk reduction strategies

Optimize asthma control before surgery. Nebulizers with albuterol and ipratropium are recommended. A short course of systemic corticosteroids may be necessary. For patients who have received systemic corticosteroids for more than 3 weeks during the past 6 months, hypothalamic-pituitary-adrenal axis suppression should be assumed, it is recommended to give receive stress-dose coverage of 100 mg hydrocortisone every 8 hours intravenously during the surgical period and then reduce the dose rapidly within 24 hours following surgery.

  • Patients need education for lung expansion, deep breathing and coughing, and incentive spirometry techniques prior to surgery.

  • Patients undergoing elective surgery should be encouraged to abstain from smoking for at least 8 weeks before surgery. But one concern about smoking cessation in the immediate preoperative period is that abrupt removal of the irritant effect of cigarette smoke can inhibit coughing and lead to retention of secretions and small airway obstruction.

  • Prophylactic antibiotics do not lead to a reduction in pulmonary complications, but any underlying respiratory infections treatment should be performed.

  • Patients should be treated with bronchodilators and chest physical therapy, which may help significantly to reduce pulmonary complications. It is reasonable to give a preoperative course of systemic steroids to patients who have a persistent wheeze, functional limitation, or severe air flow obstruction despite bronchodilator therapy.

  • If approach to general anesthesia, smooth induction and extubation should be perform to minimize tracheal stimulation.

  • Epidural or spinal anesthesia should be concerned to reduce postoperative pulmonary complications, such as deep vein thrombosis, pulmonary embolism, pneumonia, and respiratory depression.

Chronic obstructive pulmonary disease (COPD)

Perioperative evaluation

  • A careful preoperative evaluation of patients should include identifying high-risk patients and optimizing their treatment before surgery.

  • The benefits of elective surgery must be weighed against these complications.

  • Elective surgery should be deferred in patients who are symptomatic, have poor exercise capacity, or have acute exacerbation since insufflation of abdominal is associated with reduction in vital capacity functional residual capacity.

  • History of smoking, poor exercise tolerance, unexplained dyspnea, or cough should be noted.

  • Presence of decreased breath sounds, wheezes, crackles, or a prolonged expiratory phase on physical examination may identify an unrecognized pulmonary disease.

  • Laboratory studies for blood tests, an electrocardiogram (ECG), and chest radiograph are necessary.

  • Routine preoperative pulmonary function tests and an arterial blood gas are not necessary since history and exam can assess severity, except for some severe cases, especially for laparoscopic appendectomy in the elderly.

Perioperative risk reduction strategies

Patients undergoing elective surgery should be encouraged to abstain from smoking for at least 8 weeks before surgery. But one concern about smoking cessation in the immediate preoperative period is that abrupt removal of the irritant effect of cigarette smoke can inhibit coughing and lead to retention of secretions and small airway obstruction.

  • Patients need education on lung expansion, deep breathing, and coughing and incentive spirometry techniques prior to surgery.

  • Prophylactic antibiotics do not lead to a reduction in pulmonary complications, but any underlying respiratory infections treatment should be performed.

  • Patients should be treated with bronchodilators and chest physical therapy, which may help significantly to reduce pulmonary complications. It is reasonable to give preoperative course of systemic steroids to patients who have a persistent wheeze, functional limitation, or severe air flow obstruction despite bronchodilator therapy.

  • If approach to general anesthesia, smooth induction and extubation should be perform to minimize tracheal stimulation.

  • Epidural or spinal anesthesia should be managed to reduce postoperative pulmonary complications, such as deep vein thrombosis, pulmonary embolism, pneumonia, and respiratory depression.

Patients with a history of pulmonary disease are at increased risk of developing postoperative complications. Air embolism, fat emboli, or bibasilar atelectasis may occur given the effect of pneumoperitoneum with a laparoscopic appendectomy approach.

d. Renal-GI:

Given the nature of appendicitis, patients often have fever, poor oral intake, or even sepsis, which easily cause dehydration. Patients are also volume depleted from diuresis and fluid restriction. Acute renal failure is rarely developed, but it may occur in patients with impaired renal function.

Perioperative evaluation

Patients with chronic kidney disease should be well evaluated. Inadequate fluid status, electrolyte issues, anemia and bleeding, and dialysis issues must be considered simultaneously. Laboratory tests for baseline creatinine, BUN, sodium, and hemoglobin should be performed. Urinalysis may be indicated in patients susceptible to urinary tract infections, such as those with multiple sclerosis or spinal injury. A careful evaluation also is needed for any aspiration risk including history of reflux, heartburn, hiatal hernia, poor gastric emptying, and NPO status.

Perioperative risk reduction strategies

  • Volume and acid-base disturbances should be appropriately assessed and optimized. Chronic metabolic acidosis may decrease the effectiveness of some local anesthetics. Patients on dialysis should be operated on soon after to minimize electrolyte and volume disturbances.

  • If potassium >5.5 mmol/L, consider avoiding general anesthesia. Hyperkalemia can be improved to avoid arrhythmias by the intravenous administration of an insulin-dextrose combination, bicarbonate or calcium, and polystyrene binding resins or dialysis can remove excess stores of potassium.

  • To correct anemia, consider erythropoietin several weeks before surgery, and possible blood transfusion.

  • To reduce bleeding risk, perform dialysis on day prior to surgery to decrease uremia but avoid surgery within 12 hours of heparinized dialysis, and avoid antiplatelet agents and other agents with increased bleeding risk within 72 hours of surgery.

  • For the patient with symptoms of GI reflux and/or bowel obstruction, consider antiacid and antiemetic treatment. Rapid-sequence induction should be considered to minimize the risk of aspiration if under general anesthesia.

e. Neurologic:

Acute issues: Acute stroke, transient ischemic attack, uncontrolled seizure, altered mental status, new-onset headache and visual disturbances, acute drug and alcohol withdrawal, and other unstable medical condition should be evaluated and treated prior to elective surgery.

Chronic disease: Patients with history of carotid stenosis disease require relatively higher blood pressure to maintain adequate cerebral perfusion; it is important to avoid abrupt sympathectomy if regional anesthesia chosen. Antiepileptic drugs should be continued for patients with underlying epilepsy. Electrolyte abnormalities, as a result of the cerebral salt wasting, inappropriate antidiuretic hormone secretion (SIADH), or central diabetes insipidus, should be closely monitored and corrected prior to surgery.

f. Endocrine:

With the stresses of anesthesia and surgery, patients with diabetes mellitus may increase the secretion of epinephrine, norepinephrine, cortisol, and growth hormone, which are all insulin antagonists and cause insulin resistance at the tissue level, contributing to hyperglycemia, ketosis, and acidosis.

Patients with diabetes mellitus are also at risk for hypoglycemia because of prolonged fasting, hypoglycemic medications, inadequate nutritional therapy, sedation, and postoperative gastrointestinal problems (e.g., vomiting, gastroparesis, and ileus), so appropriate glucose monitoring every 1 to 2 hours should be performed to avoid unrecognized hypoglycemia.

Patients on insulin should receive continuous IV insulin started at 1.0 unit/hr of regular insulin by infusion pump during surgery, which can be adjusted depending on blood sugar monitoring. IV glucose infusion should also be given to prevent hypoglycemia.

Patients with mild hyperthyroidism can go to surgery with preoperative beta-blockade, but elective surgery should be postponed in those with moderate to severe disease until they are euthyroid. The thyrotoxic patient undergoing urgent or emergent surgery needs premedication with antithyroid agents, beta-blockade, and possibly corticosteroids.

Elective surgery in patients with mild to moderate hypothyroidism is probably safe since levothyroxine has a half-life of 5 to 9 days, and so doses can be missed for several days. Patients with severe hypothyroidism who require urgent or emergent surgery should be treated perioperatively with intravenous T3 or T4 and glucocorticoids.

For patient on chronic glucocorticoids, stress dose of steroids, such as hydrocortisone 100 mg can be given every 8 hours to prevent adrenal insufficiency.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

The immunocompromised state may alter the normal response to acute infection and wound healing in patients who have undergone organ transplantation or chemotherapy or are infected with the human immunodeficiency virus.

Appendicitis most commonly affects children aged 10 to 19. Perforation is common because of the difficulty in obtaining an accurate history, and infants often present with symptoms later in their disease course.

Appendectomy in pregnancy can occur in any trimester. Perforation is more common in the third trimester because the typical symptoms may not present due to displacement of the appendix by the gravid uterus. Ultrasound is a useful first radiologic study and is accurate because it has no known adverse fetal effects. Although laparoscopic appendectomy has become increasingly popular, the gravid uterus can make laparoscopic visualization difficult; carbon dioxide insufflation of the abdomen results in fetal hypercarbia and decreased placental blood flow, so the open approach is advised.

4. What are the patient's medications and how should they be managed in the perioperative period?

Be sure to include herbals, vitamins, and relevant OTC drugs.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Anti-inflammatory medications

Antibiotic regimens should cover most commonly encountered organisms, including aerobic and anaerobic organisms. Administer one dose preoperative antibiotics with suspected appendicitis if necessary and stop administration after surgery if there is no perforation. Patients who present with perforated appendicitis may need administration of a combination of ampicillin, clindamycin (or metronidazole), and gentamicin. Alternative regimens include ampicillin/sulbactam, cefoxitin, cefotetan, piperacillin/tazobactam, ticarcillin/clavulanate, and imipenem/cilastatin.

Antidiabetic agents

For diabetic patients who are on oral hypoglycemic agents, newer-generation sulfonylureas, such as glyburide and glipizide, can be withheld the morning of the surgery. Metformin should be stopped 24 hours before the procedure. Long-acting insulin should be taken at half the morning dose, and short-acting insulin should be stopped. Patients with an insulin pump should continue their lowest (typically night-time) basal rate. Hourly finger sticks can be performed, and subcutaneous insulin or an insulin drip can be started if blood glucose levels become problematic during the procedure.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac: Patients on beta-blockers should continue these perioperatively; a rate goal of less than 70 beats/minute has survival benefits in high-risk patients. Statins and digoxin should be continued on the morning of surgery. Angiotension-converting enzyme inhibitors (ACEI) or angiotension II receptor blocking agents (ARBs) should be on held on the morning of surgery.

Pulmonary: Recommend to continue beta-agonists and bronchodilator therapy as needed. Nebulizers may be considered in the morning of surgery.

Renal: Diuretics should be held in the day of surgery since patients with appendicitis may have volume depletion due to the fever and poor mouth intake.

Neurologic: Antiepileptic and Parkinson’s medications should be continued perioperatively. The perioperative bleeding risks and cerebrovascular thrombotic risks should be balanced for patients on antiplatelet therapy with the assistance of a neurologist.

Antiplatelet: For patients who are receiving aspirin for primary prevention of myocardial infarction/stroke, discontinuation of antiplatelet drugs 1 week before surgery is recommended. For patients at a high risk of cardiac events (e.g., myocardial infarction within the past 3 months or with the insertion of a coronary stent, etc.), continuation of aspirin up to and beyond the time of surgery is recommended. The risk of bleeding and the risk of thrombosis require a discussion with a cardiologist.

Psychiatric: Tricyclic antidepressants (TCAs) should not be stopped until the day of surgery and resumed as oral fluids allowed. Tapering should be done over 1 to 2 weeks to minimize sleep disturbances. Use of meperidine in patients taking monoamine oxidase inhibitors (MAOIs) may cause fever, hallucinations, or rigidity.

j. How To modify care for patients with known allergies -

Avoid any drugs known to cause allergic reactions. Treatment of a drug allergy may include stopping the offending medication and support for the symptoms (hives and itching). Medications prescribed may include antihistamines such as diphenhydramine (Benadryl)), oral steroids (prednisone), or histamine blockers such as cimetidine or ranitidine. Other medications may be used for severe reactions, including epinephrine, which is inhaled, given intravenously, or injected under the skin.

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

Latex-sensitive patients should be scheduled as the first case of the day if possible since aerosolized latex particles are at a low level then. A medical alert sign should be posted to indicate patient’s allergy on armbands, hospital charts, beds, and room entrances. Patients must be kept within a latex-free environment and protected from further latex contact to avoid serious complications. Medications should not be drawn up through rubber-stoppered vials or allowed to sit in preloaded syringes that contain latex rubber; latex ports should not be used for intravenous injections. Premedication with antihistamines, steroids, and histamine H2 blockers is not routinely performed since the anaphylactic reactions may have occurred despite such pretreatment. Latex-free resuscitation equipment must be available. Diphenhydramine (Benadryl) may be used for urticaria. An emergency injection of epinephrine and corticosteroids should be available. Treatment should be continued with monitoring after symptoms resolve.

l. Does the patient have any antibiotic allergies? (common antibiotic allergies and alternative antibiotics)

Penicillin-allergic patients should avoid beta-lactamase type antibiotics and cephalosporins. A combination of intravenous metronidazole and ciprofloxacin is commonly used.

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia (MH)

Documented: Avoid all trigger agents such as succinylcholine and inhalational agents. Follow a proposed general anesthetic plan: Regional anesthesia (spinal or epidural with local anesthetics) should be considered for individuals susceptible to MH. If laparoscopic appendectomy is performed, a total intravenous anesthesia (TIVA) is appropriate. Anesthetic machine tubing, circuit, bag, and absorber should be replaced, and oxygen should be run at 10 L/min for at least 20 minutes. All inhalation anesthetics (except nitrous oxide) and depolarizing muscle relaxants (e.g., succinylcholine) should be avoided. Intraoperative management includes continuously monitoring of end-tidal carbon dioxide levels, blood oxygen saturation, and core body temperature.

Ensure an MH cart is available [MH protocol]. An MH cart or kit containing required drugs (an adequate supply of dantrolene), equipment, supplies, and forms should be immediately accessible to operating rooms. Dantrolene 2.5 mg/kg IV should be administrated as soon as possible; repeat every 5 to 10 minutes until symptoms are controlled or a total dose of up to 10 mg/kg is given. Transfer the patient to an acute care facility when needed.

Family history or risk factors for MH: MH is inherited. Genetic counseling is recommended for anyone with a family history of multiminicore myopathy, muscular dystrophy, or central core disease.

Local anesthetics/ muscle relaxants

True allergies to the local anesthetics are exceedingly rare and usually involve an ester agent. It is more common to be allergic to preservatives in the local anesthetic solution. Allergy to an ester-based anesthetic (cocaine, procaine, tetracaine, chloroprocaine, and benzocaine) does not imply an allergy to the amine-based anesthetics (lidocaine, bupivacaine, and mepivacaine).

Muscle relaxants account for 60% to 70% of all allergic reactions occurring during general anesthesia. Most reactions are immunologic origin (IgE-mediated anaphylaxis) or related to direct stimulation of histamine release (anaphylactoid reactions). In terms of anaphylactic risk, NMBAs could be classified in three groups: high risk (rocu, succi), intermediate (vecu, pancu), and low risk (miva, atrac, cisatrac).

5. What laboratory tests should be obtained and has everything been reviewed?

Common laboratory normal values will be same for all procedures, with a difference by age and gender.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

A general statement about the various options should be covered here. Specifics regarding the appropriateness (for the general option) and the benefits/drawbacks/issues (e.g., antiplatelet agents for regional) should be included in each section. In the regional section, include any adjuvants like common sedation or general. A discussion of patient positioning and any special concerns with regard to positioning injury should be included.

Appendectomy can be performed either under regional anesthesia (spinal, epidural, combined spinal-epidural, peripheral nerve blocks) or general anesthesia. There is no basis for an overall analysis to demonstrate the differences in mortality between regional and general anesthesia for appendectomy.

a. Regional anesthesia

Neuraxial

Spinal or epidural anesthesia can be performed for appendectomy.

Benefits:

  • Avoid potential difficult airway management and related complications such as airway trauma and laryngospasm.

  • Patients with pulmonary disease may benefit from less effect on pulmonary function and oxygenation.

  • In patients with heart diseases, reduce stress and cardiac work.

  • Better pain control than intravenous narcotics

  • Requires less systemic narcotic and lower incidence of nausea and vomiting as a result

  • Potentially reduce blood loss and perioperative rates of DVT

Drawbacks:

  • Neuraxial analgesia is contraindicated in patients on anticoagulants; the epidural may not appropriate for the consequent anticoagulants.

  • Neuraxial analgesia cannot effectively inhibit the stretch of appendix and bowel during the surgery. May need additional narcotics and sedation to increase pain threshold.

Issues:

  • Inadvertent high spinal or epidural block produces myocardial depression and reduction in venous return, aggravating the hemodynamic effects of tension pneumoperitoneum, which may require induction of general anesthesia with securing of the airway.

  • The high block postdural puncture headache occurs in 3% with spinals and 1% with epidurals. The risk seems to be higher with younger age and larger size of the needle. It would be treated initially with hydration and pain medicines, and essentially an epidural blood patch.

  • It may cause low blood pressure; hydrating patients prior to placement may prevent it and medication treatment is necessary as needed. Hemodynamics should be monitored. Backache is an infrequent problem due to ligament strain.

  • Accidental intravascular injection of local anesthetic agent may result in cardiovascular and central nervous system toxicity.

  • Nerve may be damaged including paralysis, loss of bladder and bowel function, or loss of sexual function. Other issues that can occur include infection, epidural hematoma, allergic reactions, seizures, cardiac arrest, and death. Although the results of these are severe, they occur very rarely.

Peripheral nerve block

Local anesthetic with skin infiltration, ultrasound-guided iliohypogastric nerve block, or lumbar paravertebral block can be combined with general anesthesia.

Benefits:

  • Give an alternative to general anesthesia for surgery.

  • Reduce opiate requirement intraoperatively and provide postoperative pain management.

  • Reduce the risk of postoperative fatigue/confusion, and the incidences of nausea and vomiting.

  • Earlier recovery of bowel function.

  • Earlier discharge from the recovery room and hospital and easier participation in physical therapy.

Drawbacks:

  • Peripheral nerve block most likely cannot provide a complete block with need for surgical anesthesia.

Issues:

Peripheral nerve block can have an incomplete block with need for conversion to general anesthesia. Permanent nerve injury may occur but rarely.

b. General anesthesia

Benefits:

  • Facilitates complete control of the airway, breathing, and circulation

  • Allows proper muscle relaxation for prolonged periods of time

  • Can be adapted easily to unpredictable procedure duration

  • Can be administered rapidly and is reversible, especially for emergency appendectomy

  • Reduces intraoperative patient awareness and recall

  • Can be used in cases of sensitivity to local anesthetic agent

Drawbacks:

  • Requires increased complexity of care and associated costs

  • Can induce physiologic fluctuations that require active intervention

  • Could associated with some complications such as nausea or vomiting, sore throat, shivering, and delayed return to normal mental functioning

Other issues:

Associated with malignant hyperthermia, but rare,

Airway concerns Patients usually have a full stomach for emergency cases and nausea or vomiting, so a rapid sequence intubation with cricoid pressure should be used to decrease risk for aspiration. Airway management becomes particularly problematic in the parturient with appendectomy due to the normal physiologic changes that take place during pregnancy.

c. Monitored anesthesia care

Monitored anesthesia care is not an option as the sole anesthetic given the intensity of pain with insufflations of abdomen.

6. What is the author's preferred method of anesthesia technique and why?

If appendectomy is performed laparoscopically, general anesthesia is preferred since total proper muscle relaxation is required given the effect of pneumoperitoneum. The use of nitrous oxide is controversial because of concerns about its ability to produce bowel distention during surgery and the increase in postoperative nausea. If open appendectomy is considered, procedure could be done under either general or regional anesthesia.

Airway management becomes particularly problematic in the parturient due to the normal physiologic changes that take place during pregnancy, so regional anesthesia is more popular in pregnancy patients, but if emergency appendectomy needed, general anesthesia can provide a rapidly and complete airway controlled technique.

Appendectomy in children is recommended to be performed under general anesthesia because regional anesthesia may be difficult to perform in those who have anxiety about the procedure or pain with local injection.

Regional anesthesia should be considered for individuals susceptible to MH. If general anesthesia is needed for laparoscopic appendectomy, TIVA is appropriate.

Prophylactic antibiotics

Antibiotics used in the current literature prior to appendectomy for enteric gram-negative coverage include gram-negative bacilli such as metronidazole plus cefalothin or cefazolin or gentamicin or alternatively cefotetan. These should be given within 30 to 60 minutes before incision; readministration at one to two half-lives of the antibiotic is recommended for the duration of the procedure. Postoperative administration is not recommended.

Surgical procedure

Types and duration of surgical procedures need to be known. If an elective laparoscopic appendectomy is performed or emergency open appendectomy approach is taken for ruptured appendix, peritonitis, or septic patient, general anesthesia with rapid sequence intubation is indicated, which provides ideally muscle relaxation and mechanical breathing control. If elective open appendectomy is planned, regional anesthesia block may be considered to minimize the complications related to general anesthesia.

Intraoperative management

In the laparoscopic approach, it is necessary to place a nasogastric tube prior to insufflation of the abdomen to decompress the stomach, decreasing the aspiration due to pneumoperitoneum. A Foley catheter is typically needed to decompress the urinary bladder, allowing safe placement of trocars. The use of sequential compression stockings to prevent DVT is necessary due to decreased venous return from the lower extremities caused by the pneumoperitoneum.

Intraoperative complications

For laparoscopic appendectomy, abdominal insufflation may be associated with vasovagal reflex or decreased venous return. If this occurs, the insufflation should be stopped immediately and the abdomen desufflated.

Insufflation of gas into a major vessel may result in air embolism. Obstruction of right heart outflow can occur with complete cardiovascular collapse. Emergency treatment is to discontinue CO2 insufflation, evacuate pneumoperitoneum, place patient in the head-down position with left lateral decubitus position, insert central venous pressure line for possible aspiration of air embolism, and maintain vigorous ventilatory support.

Visceral trauma can occur at any time during a laparoscopic procedure. There is increased risk in those patients who have undergone previous surgical procedures with abdominal adhesions and in those with distended hollow organs (i.e., urinary bladder, stomach, and intestine). Nasogastric decompression of the stomach and Foley catheter drainage of the bladder will reduce the risk of injury to these organs.

Other complications include peritoneal tears, hemorrhage, subcutaneous emphysema, and nerve injury. Complication rates should be dropped with increased surgical experience.

Cardiac complications:If regional anesthesia (spinal or epidural) is used, profoundhypotension can occur due to the high spinal effect such as bloodpooling and impairment of venous return, which may need to convert togeneral anesthesia. Intraoperative fluid administration and vasopressorsare recommended to use for treating this problem. Introduction ofcapnoperitoneum and positioning in laparoscopic appendectomy may affectsystolic or diastolic performance significantly in patients withmanifest cardiovascular disease. In this case, the insufflation needs to be stopped and released immediately.

Pulmonary complications: Patientswho have poor exercise capacity and symptomatic history may have acuteexacerbation since insufflation of the abdomen is associated withreduction in vital capacity functional residual capacity with a laparoscopic appendectomy approach. Other possible complications include fat emboli and bibasilar atelectasis.

Neurologic complications: Ulnar nerve or brachial plexus injury mayoccur due to positioning pressure secondary to long duration of surgeryor steep Trendelenburg/reverse Trendelenburg position for patients withhigh body mass index. Proper positioning and padding are necessary, and avoid stretching or direct compression at the neck or axilla.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

Patients should be awake and responsive. Muscle relaxation should be adequately reversed. Adequate tidal volume should be achieved by spontaneous ventilation. There should be no signs of internal hemorrhage.

c. Postoperative management

Analgesic modalities

Skin infiltration of a long-acting local anesthetic around the incision site should be performed by the surgeon intraoperatively for postoperative pain relief. Neuraxial opioids may be appropriate for regional anesthesia with proper respiratory monitoring. PCA opioids are used intravenously and then transitioned to oral opioids and/or adjunct acetaminophen and NSAIDs.

Level of bed acuity

The type of postoperative bed depends on the patient's preoperative comorbidities and intraoperative course. Elective appendectomy is commonly performed in an ambulatory manner with the patient discharged home in the day of surgery. If an emergency or complicated appendectomy is performed, patients should recover in the PACU followed by admittance to a general surgical floor or directly to an intensive care unit.

Postoperative complications

Postoperative nausea and vomiting (PONV) is one of the most common postoperative complications, affecting up to as many as 40% of patients after general anesthesia, most likely in young, nonsmoking, overweight women and patients with a history of PONV and motion sickness. Preoperative supplemental fluid administration, using NSAIDs for analgesia instead of administering opioid and nitrous oxide, has been described to minimize emesis after laparoscopic appendectomy. Prophylactic use of antiemetics and regional anesthesia are also appropriate methods for reducing PONV.

Deep venous thrombosis (DVT) and pulmonary embolism (PE) are major causes of morbidity and mortality in the perioperative period, but appendectomy is associated with a low incidence. The prophylactic use of pharmacologic agents and/or mechanical devices has been recommended and therapy is continued to ambulation, especially for patients with previous DVT or PE.

Pneumatic compression devices prevent DVT or PE by producing an increase in lower extremity blood flow via augmentation of venous return. Warfarin should be used with monitoring of the international normalized ratio (INR) of the prothrombin time and requires close dose adjustment. Low-dose unfractionated heparin used with close monitoring of the aPTT with dose adjustments. Low-molecular-weight heparin (LMWH) does not require monitoring of the aPTT. Regional anesthesia (spinal or epidural), compared with general anesthesia, has been shown to reduce the risk of DVT; however, regional anesthesia alone is not considered effective prophylaxis, and low-dose warfarin or LMWH should also be used.

Shivering may more commonly occur after hypothermia, inhalational anesthetics, or anticholinergic premedication, which may be due to alteration in the descending control of spinal reflexes after general anesthesia. Treatment includes maintaining normothermia and oxygenation; meperidine 25 mg should be considered.

Aspiration pneumonitis is a sterile inflammation of the lungs from inhaling gastric contents and presents with history of vomiting or regurgitation with rapid onset of breathlessness and wheezing. A nonstarved patient undergoing emergency appendectomy is particularly at risk. Urgent treatment includes bronchial suction, positive pressure ventilation, prophylactic antibiotics, and IV steroids.

Common urinary problems may be associated with appendectomy. Urinary retention is a common immediate postoperative complication. Treatment includes intermittent sterile catheterization. UTI is also very common, especially in women, and may not present with typical symptoms. Treat with antibiotics and adequate fluid intake.

What's the Evidence?

"ACC/AHA Practice Guideline Update for Perioperative Cardiovascular Evaluation for Noncardiac Surgery—Executive Summary". J Am Coll Cardiol. vol. 39. 2002.

Kwittken, PL, Becker, J, Oyefara, B, Danziger, R, Pawlowski, N, Sweinberg, S. "Latex hypersensitivity reactions despite prophylaxis". Allergy Proc. vol. 13. 1992. pp. 123-7.

Miller, RD, Fleisher, LA, Wiener-Kronish, JP, Young, WL, Eriksson, LI. Anesthesia: Expert Consult. Elsevier Health Sciences. 2009.

Barash, PG, Cullen, BF, Stoelting, RK. Clinical Anesthesia. Lippincott, Williams and Wilkins. 2009.

Morgan, GE, Mikhail, MS, Murray, MJ. Clinical anesthesiology. Lange Medical Books/McGraw-Hill. 2005.

HadŽiĆ, A. Textbook of regional anesthesia and acute pain management. McGraw-Hill Medical Pub. Division. 2007.

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