Anesthesiology

Appendectomy

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What the Anesthesiologist Should Know before the Operative Procedure

Around 280,000 appendectomies are performed annually in the United States, with the highest incidence in patients 10 to 19 years of age. Mortality is 0.1% in children and young adults, although it increases 30-fold in those over 65 years of age, owing to a higher risk of complicated appendicitis and need for open operations. The lifetime risk of appendicitis is 6% to 7%. Left untreated, appendicitis rapidly progresses to full-thickness gangrene and perforation, in as little as 36 hours after symptoms begin. Uncomplicated appendicitis is typically managed with prompt appendectomy, while perforated appendicitis with associated abscess is often drained percutaneously, followed by delayed appendectomy.

1. What is the urgency of the surgery?

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

Antibiotics appear to rapidly reduce inflammation in uncomplicated appendicitis and should be begun immediately. Outcomes from immediate surgery (“emergent”) and within 24 hours of emergency presentation are indistinguishable.

Emergent: This is not applicable for uncomplicated appendicitis.

Urgent: Antibiotic administration and delay of surgery from 6 to 24 hours after admission have no impact on clinical outcomes.

Elective: Interval appendectomy is an elective procedure where patients are treated with antibiotics and return to the operating room for appendectomy 8 to 12 weeks after initial presentation.

2. Preoperative evaluation

Classic symptoms include periumbilical pain migrating to the right lower quadrant over several hours, fever, nausea, and vomiting. The presence of peritonitis, Rovsing’s sign, and psoas stretch or obturator signs are common. Confirmatory imaging commonly includes ultrasound and CT scan.

Medically unstable conditions warranting further evaluation include none related specifically to appendicitis. Delaying surgery may be indicated if surgery can safely be delayed up to 24 hours from presentation if needed. Obese children have a higher rate of normal appendices following appendectomy for suspected appendicitis, also known as negative appendectomy.

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

During the perioperative evaluation, assess the patient for presence of systemic manifestations of sepsis or septic shock and hypovolemia. Patients should also be assessed for their aspiration risk. Laparoscopic appendectomies are associated with reduced pain and length of stay compared to open procedures.

b. Cardiovascular system

Acute/unstable conditions include sepsis or septic shock, and hypovolemia. In baseline coronary artery disease or cardiac dysfunction, the continuation of beta blockade and avoidance of tachycardia remain helpful.

c. Pulmonary

Laparoscopy increases ventilation requirements by as much as 60% and worsens compliance and reduces functional residual capacity. For the patient with reactive airway disease (asthma), as noted, there is no change from standard management.

d. Renal-GI:

Acutely, laparoscopy may decrease glomerular filtration rate by up to 50%; pulmonary aspiration risk is increased due to peritonitis and associated ileus, as well as vomiting preoperatively. In chronic disease, perioperative mortality is increased in patients with chronic renal failure.

e. Neurologic:

Acutely, hypercapnea due to CO2 insufflation may increase intracranial pressure, while Trendelenburg positioning increases venous pressure. There are no issues relating to chronic disease.

f. Endocrine:

N/A

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)

N/A

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

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

Antibiotics, antiemetics, and analgesics should be continued through the perioperative period.

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

Cardiac: Continue beta-blockers; hold angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs). Diuretics may be continued if the patient is euvolemic and is without electrolyte disturbances.

Pulmonary: All medications should be continued.

Renal: Hold ACE inhibitors and ARBs. Diuretics may be continued if the patient is euvolemic and is without electrolyte disturbances.

Neurologic: All medications can be safely continued.

Antiplatelet: If given for prophylaxis, they should be held for as long as possible preoperatively and reversed if applicable. If given to treat an acute condition, the risk of withholding or reversing these medications should be weighed against the risk of significant surgical bleeding.

Psychiatric: All medications can be safely continued.

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

N/A

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.

N/A

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

N/A

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: total intravenous anesthesia with propofol ± opioid infusion ± nitrous oxide. Ensure an MH cart is available [MH protocol].

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

In all patients, a complete blood count and electrolytes should be evaluated preoperatively, to assess for elevation in white blood cell count and electrolyte disturbance due to dehydration. Common laboratory normal values will be same for all procedures, with a difference by age and sex.

Significant hemorrhage and transfusion preoperatively are extremely rare; if the patient is anemic, other causes should be sought. Electrolytes should be routinely measured, as well as blood urea nitrogen and creatinine, if there is suspicion of dehydration. A coagulation panel is necessary only if the history or examination is suspicious for preexisting coagulopathy. Ultrasound and CT of the abdomen are commonly performed to confirm diagnosis preoperatively.

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

General anesthesia with an endotracheal tube remains the standard practice, given the challenge of a laparoscopic procedure under neuraxial anesthesia. A rapid-sequence induction remains the most common practice, due to the concern for pulmonary aspiration, although this has not been prospectively studied. Patients are typically positioned supine, in Trendelenburg position, occasionally for extended periods.

a. Regional anesthesia is rarely used as the primary anesthetic.

Neuraxialanesthesia has been successfully described in microlaparoscopy, withreduced incidence of postoperative nausea and vomiting (PONV) andshorter PACU stay; 12 to 24 hours of analgesia is provided if neuraxialmorphine is also administered. However, it is ofteninadequate for surgery, due to diaphragmatic irritation referred to theshoulder; in one series, most patients complained of chest pain and hadsevere agitation. There is a risk of cephalad spread of hyperbaricspinal anesthetics due to Trendelenburg position and limited duration ofsingle-shot spinal anesthetic. It is contraindicated if bacteremia is suspected and relatively contraindicated in patients with sepsis.

Transversus abdominis plane (TAP) block for postoperative pain reduces morphine consumption after open appendectomy. However, TAP block for postoperative pain has no benefit for laparoscopic appendectomy.

No peripheral nerve blocks currently exist that can provide adequate surgical anesthesia for laparoscopic appendectomy.

b. General anesthesia

General anesthesia is the most effective technique; there is no limit on duration and it is the best choice for this procedure. However, there are higher rates of PONV compared to other techniques. The physiologic effects of laparoscopy are to be considered.

Airway concerns: Generally considered a "full stomach" due to peritonitis and concern for ileus, as well as concomitant constipation, nausea, and vomiting.

c. Monitored anesthesia care (MAC)

The benefits of MAC are described, and it was found to be useful in pain mapping and appendectomy for pelvic pain. However, it requires single-port microlaparoscopic technique and meticulous surgical technique. It is rarely, if ever, used in acute appendicitis.

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

Prophylactic antibiotic monotherapy is with cefotetan, cefoxitin, or cefmetazole. Multiagent therapy includes cefazolin-metronidazole; clindamycin with gentamicin or ciprofloxacin or levofloxacin or aztreonam; or metronidazole with gentamicin or ciprofloxacin or levofloxacin (SIS Guidelines, 2009).

If the appendix is found to be gangrenous or associated with perforation, abscess formation, or significant adhesions, the surgical procedure may be prolonged and technically challenging, with the potential for significant fluid shifts. After insufflation, Trendelenburg position typically improves surgical exposure.

Complications

In patients with severe valvular disease or depressed ventricular function, volume overload may occur with insufflation and Trendelenburg position. In healthy patients, severe bradyarrhythmia and cardiovascular collapse have been reported during insufflation, due to the vasovagal reflex. Inferior vena caval compression and air embolism have also been reported. Ventilatory difficulty due to steep Trendelenburg and abdominal insufflation can occur; pulmonary aspiration is rare. No specific neurologic complications are associated with this procedure.

a. Neurologic:

N/A

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

As with induction of anesthesia, the patient should be considered as having a full stomach, due to peritoneal signs and concern for ileus. Patients who have intraoperative hemodynamic instability may require postoperative mechanical ventilation.

c. Postoperative management

For laparoscopic appendectomies, intermittent or patient-controlled opioid analgesia is effective; one study showed no additional benefit for epidural morphine. For open appendectomies, TAP block is effective at reducing opioid requirements. Floor-status is usually appropriate, unless signs of perforation and peritoneal soiling are present, with associated systemic signs of sepsis, or if the patient has multiple comorbid conditions. In the immediate postoperative period, sepsis and postoperative abscess are common. Most deaths following appendectomy are due to preexisting diseases such as ischemic heart disease and are not directly due to appendicitis or sepsis.

What's the Evidence?

Harbrecht, BG, Franklin, GA, Miller, FB. "Acute appendicitis: not just for the young". Am J Surg. vol. 202. 2011. pp. 286-90.

Andersson, MN, Andersson, RE. "Causes of short-term mortality after appendectomy: a population-based case-controlled study". Ann Surg. vol. 254. 2011. pp. 03-7.

Yardeni, D, Hirschl, RB, Drongowski, RA. "Delayed versus immediate surgery in acute appendicitis: do we need to operate during the night?". J Pediatr Surg. vol. 39. 2004. pp. 464-9.

Gerges, FJ, Kanazi, GE, Jabbour-Khoury, SI. "Anesthesia for laparoscopy: a review". J Clin Anesth. vol. 18. 2006. pp. 67-78.

Istvan, J, Belliveau, M, Donati, F. "Rapid sequence induction for appendectomies: a retrospective case-review analysis". Can J Anaesth. vol. 57. 2010. pp. 330-6.

Aida, S, Baba, H, Yamakura, T. "The effectiveness of preemptive analgesia varies according to the type of surgery: a randomized, double-blind study". Anesth Analg. vol. 89. 1999. pp. 711-6.

Carney, J, Finnerty, O, Rauf, J. "Ipsilateral transversus abdominis plane block provides effective analgesia after appendectomy in children: a randomized controlled trial". Anesth Analg. vol. 111. 2010. pp. 998-1003.

Sandeman, DJ, Bennett, M, Dilley, AV. "Ultrasound-guided transversus abdominis plane blocks for laparoscopic appendicectomy in children: a prospective randomized trial". Br J Anaesth. vol. 106. 2011. pp. 882-6.

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