SECTION II. Gastrointestinal System
A Anal Fistulotomy/Fistulectomy
1. Introduction
Most perianal fistulas arise as a result of infection within the anal glands located at the dentate line (cryptoglandular fistula). Fistulas may also arise as the result of trauma, Crohn’s disease, inflammatory processes within the peritoneal cavity, neoplasms, or radiation therapy. The ultimate treatment is determined by the cause and the anatomic course of the fistula and can include fistulotomy and fistulectomy. The primary goal is palliation, specifically to drain abscesses and prevent their recurrence. This is often accomplished by placing a Silastic seton (a ligature placed around the sphincter muscles) around the fistula tract and leaving it in place indefinitely. In the absence of active Crohn’s disease in the rectum, attempts at fistula cure may be undertaken.
2. Preoperative assessment
a) History and physical examination
(1) Respiratory: A careful evaluation of respiratory status is important. If the patient has significant respiratory disease, the lithotomy position is better tolerated than the prone or jackknife positions.
(2) Musculoskeletal: Pain is likely at the surgical site and should be considered when positioning the patient for anesthetic induction. (If the patient has pain while sitting, regional anesthesia should be performed with the patient in the lateral decubitus position.)
(3) Hematologic: If regional anesthesia is planned and the patient is taking acetylsalicylic acids, nonsteroidal antiinflammatory drugs, or dipyridamole, check the platelet count and bleeding time.
b) Patient preparation
(1) Laboratory tests: As indicated per history and physical examination
(2) Diagnostic tests: As indicated per history and physical examination
(3) Medication: Standard premedication
3. Room preparation
a) Monitoring equipment: Standard
b) Drugs
(1) Standard emergency drugs
(2) Standard tabletop
(3) Intravenous fluids: 18-gauge line, normal saline/lactated Ringer’s solution at 5 to 8 mL/kg/hr
4. Anesthetic technique
General anesthesia, local anesthesia with sedation, and spinal or epidural techniques may be used.
5. Perioperative management
a) Induction: Standard. Procedures done with the patient in the jackknife position may require endotracheal intubation for airway control if a regional technique is not performed.
b) Maintenance
(1) Standard
(2) Position: Use chest support or bolster to optimize ventilation in the jackknife position; take care in positioning the patient’s extremities and genitals after turning the patient into the jackknife position. Avoid pressure on the eyes and ears after turning the patient. Avoid stretching the brachial plexus. Limit abduction to 90 degrees.
c) Emergence: No special considerations are needed. The patient is extubated awake and after return of airway reflexes.
6. Postoperative implications
a) Lithotomy position possibly leading to damage to the peroneal nerve, which can lead to foot drop.
b) Urinary retention
c) Poor wound healing
d) Atelectasis
B Appendectomy
1. Introduction
Appendectomy is performed for acute appendicitis, and a laparoscopic approach is most commonly used.
2. Preoperative assessment and patient preparation
a) History and physical examination
(1) Gastrointestinal: Patients point to localized pain at McBurney’s point, which is midway between the iliac crest and umbilicus; rebound tenderness, muscle rigidity, and abdominal guarding are noted.
(2) Pregnancy: Alder’s sign is used to differentiate between uterine and appendiceal pain. The pain is localized with the patient supine. The patient then lies on her left side. If the area of pain shifts to the left, it is presumed to be uterine.
b) Diagnostic tests
(1) The white blood cell count is elevated, with a shift to the left: 10,000 to 16,000 mm 3; 75% neutrophils.
(2) Urinalysis shows a small number of erythrocytes and leukocytes.
(3) Computed tomography and abdominal films are used.
(4) Other laboratory tests include electrolytes, glucose, hemoglobin, and hematocrit. Perform tests as indicated from the history and physical examination.
c) Preoperative medication and intravenous therapy
(1) An antibiotic is given for enteric anaerobic gram-negative bacilli.
(2) A single 18-gauge intravenous catheter is used because the patient is dehydrated from fever, anorexia, and vomiting.
3. Room preparation
a) Monitoring equipment
(1) Standard
(2) Fetal heart tone monitoring with pregnancy
b) Pharmacologic agents
(1) Standard
(2) For fetal safety, avoid teratogenic anesthetic during the first trimester
c) Position
(1) Supine
(2) Left uterine displacement with pregnancy
4. Anesthetic technique
a) Regional block: Analgesia to level T6 to T8
b) General anesthesia: Endotracheal intubation required
5. Perioperative management
a) Induction
(1) Use general anesthesia with rapid sequence induction because patients may have a nasogastric tube or are considered to have a full stomach (emergency).
(2) In the pregnant patient, special care should be taken to prevent aspiration pneumonitis.
b) Maintenance
(1) No specific indications exist.
(2) Muscle relaxation is necessary.
c) Emergence: Awake extubation secondary to rapid sequence induction
6. Postoperative implications
None are reported.
C Cholecystectomy
1. Introduction
Surgery of the upper abdomen is used in the treatment of gallstones and other diseases of the gallbladder. Open cholecystectomy is performed in patients with adhesions, previous surgical procedures, infection, or major medical problems. The mortality rate for elective cholecystectomy is less than 0.5%. In patients older than 70 years of age, the mortality rate rises to 2% to 3%, mostly because of preexisting cardiopulmonary disease.
2. Preoperative assessment
a) History and physical examination
(1) Standard
(2) Gastrointestinal assessment: Pain is localized in the right subcostal region. The patient may experience referred pain in the back at the shoulder level. Anorexia, nausea, and vomiting are common. Infection and fever are rare.
b) Diagnostic tests: These are as indicated by the patient’s history and medical condition.
c) Preoperative medication and intravenous therapy
(1) Use an antimicrobial to prevent bacteremia.
(2) Narcotics must be used with caution to minimize potential spasm in the biliary tract and sphincter of Oddi.
(3) Use a single, large-bore (18-gauge) intravenous tube with fluid replacement.
(4) Use prophylactic antiemetics and aspiration prophylaxis.
3. Room preparation
a) Monitoring equipment: Standard
b) Pharmacologic agents
(1) Standard
(2) Caution advised with use of narcotic agents because of potential changes in biliary pressure
c) Position: Supine
4. Anesthetic technique
General endotracheal anesthesia with muscle relaxation is used.
5. Perioperative management
a) Induction: Rapid sequence induction with oral endotracheal intubation if the patient is considered to have a full stomach
b) Maintenance
(1) No specific requirements
(2) Muscle relaxation per abdominal surgery
(3) Antiemetic administration
c) Emergence: Awake extubation after airway reflexes are adequate
6. Postoperative implications
a) Retraction in the right upper quadrant during surgery can lead to atelectasis in the right lower lobe; postoperative pain and splinting may lead to impaired ventilation.
b) Right intercostal nerve blocks improve postoperative pain management.
c) Use patient-controlled analgesia for pain management.
D Colectomy
1. Introduction
Colectomy is performed most commonly for adenocarcinomas and diverticulosis. Other indications include penetrating trauma, ulcerative colitis, volvulus, and inflammatory bowel disease.
2. Preoperative assessment and patient preparation
a) History and physical examination: Assess hydration status, nutritional level, and electrolyte state.
b) Diagnostic tests: These are as indicated by the patient’s condition.
c) Preoperative medication and intravenous therapy
(1) Patients may be receiving steroid therapy or immunosuppressant drugs.
(2) Bowel preparation is usually indicated with electrolyte preparations.
(3) Expect fluid shifts requiring moderate to large fluid resuscitation. Two large-bore intravenous access tubes are indicated.
3. Room preparation
a) Monitoring equipment: Standard with warming modalities
b) Pharmacologic agents: Standard
c) Position: Supine, with arms extended
4. Anesthetic technique
a) Epidural (T2 to T4 level) with “light” general anesthetic
b) General anesthesia with oral endotracheal tube (most common)
5. Perioperative management
a) Induction: Consider the possibility of a full stomach; rapid sequence induction may be indicated.
b) Maintenance
(1) Muscle relaxation is required.
(2) Closely monitor fluid and hydration status and blood loss.
(3) Avoid nitrous oxide, which may cause bowel distention.
c) Emergence: This involves awake extubation after rapid sequence induction or placement of a nasogastric tube.
6. Postoperative implications
a) Pain and splinting may lead to hypoventilation and decreased postoperative ventilation.
b) Control pain with epidural or patient-controlled analgesia.
E Colonoscopy
1. Introduction
Colonoscopy is used to examine the colon and rectum to diagnose inflammatory bowel disease, including ulcerative colitis and granulomatous colitis. Polyps can be removed through the colonoscope. The colonoscope is also helpful in diagnosing or locating the source of gastrointestinal bleeding; a biopsy of lesions suspected to be malignant may be performed.
2. Preoperative assessment and patient preparation
a) History and physical examination: Assess the patient’s hydration status, nutritional level, and electrolyte state.
b) Diagnostic tests: These are as indicated by the patient’s condition.
c) Preoperative medication and intravenous therapy
(1) Patients may be receiving steroid therapy or immunosuppressants.
(2) Bowel preparation is required for visualization of the mucosa. Use colon electrolyte lavage preparations (Colyte, GoLYTELY).
(3) One 18-gauge intravenous tube is used; adequate fluid replacement is ensured.
(4) The patient is lightly sedated with midazolam because the procedure lasts less than 30 minutes and is an outpatient procedure.
3. Room preparation
a) Monitoring equipment: Standard
b) Pharmacologic agents
(1) Standard
(2) Glucagon
c) Position: Left lateral decubitus; position changes sometimes required to aid advancement of the scope at the descending sigmoid colon junction and splenic fixture.
4. Anesthetic technique
a) Monitored anesthesia care
b) Intravenous sedation: Midazolam (Versed), fentanyl, or propofol in sedative doses
5. Perioperative management
a) Induction: Oxygenation of the patient with the use of nasal cannula or a face mask
b) Maintenance: No specific indications
c) Emergence: No specific indications
6. Postoperative implications
Complications of the procedure include perforation of the bowel, abdominal pain and distention, rectal bleeding, fever, and mucopurulent drainage.
F Esophageal Resection
1. Introduction
Esophagectomy is commonly performed for malignant disease of the middle and lower thirds of the esophagus. It may also be indicated for Barrett’s esophagus (peptic ulcer of the lower esophagus) and for peptic strictures that do not respond to dilation. Lesions in the lower third are usually approached through a left thoracoabdominal incision, whereas middle-third lesions are best approached by the abdomen and right side of the chest. Resections of the esophagogastric junction for malignant disease are best performed through a left thoracoabdominal approach in which a portion of the proximal stomach is removed along with a celiac node dissection.
Total esophagectomy may be done through an abdominal and right thoracotomy approach with colonic interposition and anastomosis in the neck. Either the right or the left side of the colon can be mobilized for interposition. Both depend on the middle colic artery and the marginal artery of the colon for their vascular supply.
2. Preoperative assessment
a) History and physical examination
(1) Cardiovascular: The patient may be hypovolemic and malnourished from dysphagia or anorexia. Chemotherapeutic drugs (daunorubicin, doxorubicin [Adriamycin]) may cause cardiomyopathy. Chronic alcohol abuse may also produce toxic cardiomyopathy.
(2) Respiratory: A history of gastric reflux suggests the possibility of recurrent aspiration pneumonia, decreased pulmonary reserve, and increased risk of regurgitation and aspiration during anesthetic induction. If a thoracic approach is planned, the patient should be evaluated to ensure that one-lung ventilation can be tolerated.
(a) Chemotherapeutic drugs (bleomycin) may cause pulmonary toxicity that may worsen by high concentrations of oxygen. Many patients with esophageal cancer have a long history of smoking, with consequent respiratory impairment.
(b) Pulmonary function tests and arterial blood gases can be helpful in predicting the likelihood of perioperative pulmonary complications and whether the patient may require postoperative mechanical ventilation. Patients with baseline hypoxemia/hypercarbia on room air arterial blood gases have a higher likelihood of postoperative complications and a greater need for postoperative ventilatory support. Severe restrictive or obstructive lung disease will also increase the chance of pulmonary morbidity in the perioperative period.
b) Patient preparation
(1) Laboratory tests: Type and cross-match packed red blood cells, electrolytes, glucose, blood urea nitrogen, creatinine, bilirubin, transaminase, alkaline phosphatase, albumin, complete blood count, and platelet count. Prothrombin time, partial thromboplastin time, urinalysis, arterial blood gases, and other tests are as indicated by the patient’s history and physical examination.
(2) Diagnostic tests: Chest radiographs, electrocardiography, pulmonary function tests, and other tests are as indicated by the patient’s history and physical examination. If congestive heart failure or cardiomyopathy is suspected, consider cardiac or medical consultations.
(3) Medications: For premedication, consider aspiration prophylaxis.
3. Room preparation
a) Monitoring equipment
(1) Standard monitoring equipment
(2) Arterial line and central venous pressure or pulmonary arterial catheter as indicated
b) Additional equipment: Patient warming device
c) Drugs
(1) Standard emergency drugs
(2) Standard tabletop
(3) Intravenous fluids: Two 14- to 16-gauge IV lines normal saline or lactated Ringer’s solution at 8 to 12 mL/kg/hr; warmed fluids
(4) Blood loss possibly significant; blood immediately available
4. Anesthetic technique
General endotracheal anesthesia with or without epidural anesthetic for postoperative analgesia is administered. If the thoracic or abdominothoracic approach is used, placement of a double-lumen tube is indicated, because one-lung anesthesia provides excellent surgical exposure. If the patient is clinically hypovolemic, restore intravascular volume before induction and carefully titrate the induction dose of sedative/hypnotic agents.
5. Perioperative management
a) Induction
(1) Patients with esophageal disease are often at risk for pulmonary aspiration; therefore, rapid sequence induction is indicated.
(2) If a difficult airway is anticipated, awake intubation can be done using a fiberoptic bronchoscope.
b) Maintenance
(1) Standard maintenance uses a narcotic and/or inhalation agent. Avoid nitrous oxide.
(2) A combined technique with general and epidural anesthesia may be used. If epidural opiates are used for postoperative analgesia, a loading dose should be administered at least 1 hour before the conclusion of surgery.
(3) Position: The patient is supine, with checked and padded pressure points. Avoid stretching the brachial plexus. Limit abduction to 90 degrees. If the lateral decubitus position is used, an axillary roll and arm holder are needed. Check pressure points, including ears, eyes, and genitals. Check radial pulses to ensure correct placement of the axillary roll (a misplaced axillary roll will compromise distal pulses). Problems that can arise include brachial plexus injuries and damage to soft tissues, ears, eyes, and genitals from malpositioning.
c) Emergence
The decision to extubate at the end of surgery depends on the patient’s underlying cardiopulmonary status and the extent of the surgical procedure. The patient should be hemodynamically stable, warm, alert, cooperative, and fully reversed from any muscle relaxants before extubation. With patients who require postoperative ventilation, the double-lumen tube should be changed to a single-lumen endotracheal tube before transport to the postanesthesia intensive care unit. Weaning from mechanical ventilation should begin when the patient is awake and cooperative, is able to protect the airway, and has adequate pulmonary function.
6. Postoperative implications
a) For atelectasis or aspiration, recover the patient in Fowler’s position.
b) Hemorrhage: Check coagulation times; replace factors as necessary.
c) Pneumothorax/hemothorax: Decreased partial oxygen pressure, increased partial carbon dioxide pressure, wheezing, and coughing are noted; confirm with chest radiograph, and institute chest tube drainage as necessary. In an emergency (tension pneumothorax), use needle aspiration, supportive treatment, oxygen, vasopressors, endotracheal intubation, and positive-pressure ventilation.
d) Hypoxemia/hypoventilation: This ensures adequate analgesia and supplemental oxygen.
e) Esophageal anastomotic leak: Begin surgical repair for an esophageal anastomotic leak.
f) Pain management: Patient-controlled analgesia or epidural analgesia is used; the patient should recover in the intensive care unit or in a hospital unit accustomed to treating the side effects of epidural opiates (respiratory depression, breakthrough pain, nausea, and pruritus).
G Esophagoscopy/Gastroscopy
1. Introduction
Flexible, diagnostic esophagogastroduodenoscopy, a common procedure in pediatrics, is usually performed with the patient under heavy sedation in an endoscopy suite or special procedure area. Rigid esophagoscopy is usually performed for therapeutic indications, such as removal of a foreign body, dilation of an esophageal stricture, or injection of varices. The procedure is similar for each diagnosis and generally is performed with endotracheal intubation. Foreign body removal is normally a short procedure, whereas dilation and variceal injection can be prolonged and may require multiple insertions or removals of the endoscope. Compression of the trachea distal to the endotracheal tube by the rigid esophagoscope is not uncommon.
