CAPÍTULO 2: RESULTADOS DE LOS MÉTODOS Y PROCEDIMIENTOS
3.4 Consideraciones parciales
• Ernest Miles (1869–1947) devised the approach in the 1930s as a curative procedure for all rectal cancers. It involves resection of the anus, rectum, and a portion of the sigmoid colon, as well as a wide perineal and lymph node dissection.
• Abdominoperineal resection (APR) is now reserved for conditions where the rectum needs to be removed and there is involvement of the primary sphincter complex or tumors in the lower third of the rectum that do not have adequate clearance for sphincter preservation. It requires a permanent colostomy.
• Laparoscopy-assisted APR and low anterior resection (LAR) are more commonly performed today. LAR is a modified technique that allows for sphincter preservation.
Position
• Modified lithotomy
• Trendelenburg, as needed Incision
Midline abdominal and perineal Approximate Time
5–10 hours EBL Expected 500–1,500 mL Hospital Stay 7–10 days
Special Equipment for Surgery
• 2 table set-up (abdominal and pelvic sets)
• Long pelvic instruments, stapling devices
• Cystoscopy set with ureteric stents EPIDEMIOLOGY
Incidence
• Colorectal cancer is the 4th most common cancer and the second leading cause (10%) of all cancer-related deaths.
• From 2003 to 2007, the median age at diagnosis for colorectal cancer was 70 years of age.
At diagnosis, about 20% had distant metastasis.
• 5–10% of all colorectal cancers are associated with a familial colorectal cancer syndrome, and an additional 15–20% are associated with a familial disposition.
• Risk for colorectal cancer increases with age (90% of cases occur in patients >50 years), and with a diet rich in red meat and animal fat.
• Aspirin, NSAIDs, and COX-2 inhibitors have been reported to have protective effects against colorectal cancer.
Prevalence
• As of January 1, 2007, in the US there were approximately 1,112,493 men and women alive with a history of colon and/or rectal cancer.
• Based on rates from 2005 to 2007, 5.12% of men and women born today will be diagnosed with cancer of the colon and/or rectum during their lifetime.
• High incidence of local recurrence despite margin-free resection Mortality
• The overall 5-year relative survival in the US for 1999–2006 was 65.0%; for high-risk patients it is 20%.
• Hormone replacement therapy has been shown to significantly reduce mortality in women with colorectal cancer.
ANESTHETIC GOALS/GUIDING PRINCIPLES
• Patient population with sequelae related to the primary pathology and significant medical comorbidities (age, smoking, diabetes, hypertension, atherosclerosis, coronary artery disease, malnutrition). Optimize preoperative comorbid burden for optimal postoperative recovery.
• Maintenance of tissue oxygenation, perfusion, and euvolemia. Patients are often placed on a clear liquid diet 1–3 days prior to surgery, combined with bowel prep (laxative, enemas, whole gut irrigation with saline via a nasogastric tube, polyethylene glycol electrolyte lavage, or mannitol solution).
• Effective analgesia (epidural preferred for open procedures)
• Extubation at the end of surgery
• Postoperative monitoring in a high-dependency unit for 48 hours
PREOPERATIVE ASSESSMENT
SYMPTOMS
• Symptomatic, depending on the size and location of the tumor
• Change in bowel habits and pencil stools
• Rectal or lower abdominal pain, spotting of blood in stool, lower GI bleeding, hematochezia, and tenesmus
• May be acutely or chronically ill depending on the primary pathology (Crohns disease, ulcerative colitis)
History
• Inflammatory bowel diseases (Crohns disease, ulcerative colitis), inherited colon cancers (familial adenomatous polyposis, Gardner syndrome, Peutz–Jeghers syndrome, juvenile polyposis, and hereditary non-polyposis colon cancer)
• Careful assessment of the sequelae and complications of the primary colonic/rectal pathology, medical comorbidities, nutritional and functional status
Signs/Physical Exam
• Systemic signs of inflammatory bowel disease (IBD)
• Anemia, weight loss, fever of unknown origin
• Abdominal wall and/or internal colonic fistulae
• Palpable mass in the recto-sigmoid on examination MEDICATIONS
• Therapy for IBD: Antidiarrheals, aminosalicylates (5-ASA), corticosteroids, immunomodulators (azathioprine and 6-mercaptopurine, cyclosporine), antibiotics, and pain medications
• Patient may have recently completed adjuvant chemoradiation prior to surgery and/or planned for after surgery.
• Chemotherapy for colorectal cancer is 5-FU and leucovorin based. Irinotecan or oxaliplatin is added in metastatic disease.
• Medications for the comorbidities (antihyperglycemics, antihypertensives, anticholesterol medications, aspirin, etc.)
DIAGNOSTIC TESTS & INTERPRETATION Labs/Studies
• CBC, PT/PTT, creatinine, prealbumin, and LFTs
• Electrolytes if on diuretics, ACE I, renal insufficiency
• Colonoscopic evaluation (location, size, and number of masses)
• CT scan (tumor location, size, perirectal and vascular involvement, peritoneal and liver metastasis)
• Other tests (TEG, ECG, CXR, cardiac echocardiogram, exercise stress test, PFTs) as indicated CONCOMITANT ORGAN DYSFUNCTION
• Anemia from bleeding or occult blood loss
• Metastasis: Abdominal pain (hepatomegaly) and liver dysfunction from hepatic metastasis;
skeletal pain from bony metastasis; ascites from peritoneal dissemination; bladder dysfunction, sacral or sciatic neuropathy, and vaginal discharge and bleeding from pelvic metastasis
• Obesity/malnutrition
• Inflammatory bowel disease and its associated sequelae
• Age-related morbidities: Diabetes, hypertension, coronary artery disease
TREATMENT
PREOPERATIVE PREPARATION Premedications
• Anxiolytic and analgesic medications, as needed
• Gastric volume reducing and acid-neutralizing medications, if indicated
• Continue appropriate medications (antibiotics, anti-inflammatory/immunomodulators, antihypertensives, antiarrhythmics, and others) as needed
• There is an increasing trend to use alvimopan to hasten recovery of bowel function.
Special Concerns for Informed Consent
• Blood consent for possible transfusion
• Consent for epidural catheter for postoperative analgesia
• Potential for postoperative intubation and intensive care Antibiotics/Common Organisms
• Prophylactic cefotetan or cefoxitin; metronidazole plus an aminoglycoside may be used for cephalosporin allergy.
• Gram-negative aerobes and anaerobic bacteria
• Mechanical bowel preparation decreases fecal bulk, but does not decrease the concentration of bacteria in the stool.
INTRAOPERATIVE CARE Choice of Anesthesia
• General anesthesia with ETT
• Epidural catheter for postoperative analgesia: Need to rule out contraindications, review medication list (herbals, clopidogrel, low-molecular-weight heparin, or other drugs that alter coagulation), consider preoperative PT/PTT/INR or other advanced coagulation tests as needed (TEG, PFA). Not contraindicated with usual thromboprophylaxis for postoperative DVT (heparin 5,000 U SQ BID).
Monitors
• ASA standard monitors
• Arterial line (beat-to-beat blood pressure monitoring, systolic pressure variation [SPV] to evaluate intravascular volume status, blood draws for lab work); consider placing the arterial line pre-induction for high-risk patients.
• 2 large-bore IVs for volume resuscitation if needed. Central line access is not usually necessary unless there is poor IV access or a need for postoperative TPN.
• Foley catheter: Ureteric stents are placed preoperatively to identify ureters during the resection.
Induction/Airway Management
Standard induction technique and strategies to maintain hemodynamic stability and full stomach precautions if indicated
Maintenance
• Avoid nitrous oxide. Air–oxygen mixture with an FiO2 of 0.5 will help identify oxygenation issues early.
• Continuous epidural infusion of local anesthetic/narcotic mixture may be used for analgesia throughout the procedure.
• Nasogastric tube placement may be requested.
• Volume: APR is a major procedure with complex bowel resection; bleeding may be encountered from the presacral venous plexus. Additionally, insensible fluid losses can result. Intravascular volume status and maintenance of organ perfusion should be closely monitored.
• Surgeon may request intraoperative indigo carmine to rule out injury to the ureters; it may temporarily result in a decrease in the pulse oximeter reading.
• Blood glucose, serum electrolytes, ABG, ACT and other coagulation parameters as may be checked needed.
Extubation/Emergence
• Standard extubation criteria
• Post-extubation sensory–motor exam and evaluation of epidural puncture site for effectiveness and complications
POSTOPERATIVE CARE
BED ACUITY
• High-dependency unit or ICU for 48 hours
• May need monitoring of invasive hemodynamic parameters to guide fluid volume/blood product transfusion
ANALGESIA
• Epidural: Follow ASRA guidelines for maintenance and removal of epidural catheters
• Multimodal approach involving IV PCA if epidural contraindicated or laparoscopic procedure
COMPLICATIONS
• Intra-abdominal abscess, wound infections (10%), anastomotic leaks (15%)
• Postoperative ileus
• Injury to the ureters, hypogastric or parasacral nerve plexus
• Postoperative fever and leukocytosis are not uncommon.
• Adverse cardiac events (hypotension, hypertension, arrhythmias, ischemia, infarct, and CHF)
• Postoperative delirium in elderly
• Postoperative neuropathies from positioning
• Epidural site infection or hematoma (very rare) PROGNOSIS
• Overall local recurrence is 30% after a margin-free resection.
• The best prognosis in patients with locally advanced rectal cancer appears to be after preoperative chemoradiation, maximal surgical resection (margin free), and localized
intraoperative radiation therapy (IORT) in selected cases.
REFERENCES
1. Ferg BW, Berger DH, Fuhrman GM. Cancer of the colon, rectum and anus. In: Chang G, Feig BW. The M.D. Anderson surgical oncology handbook, 4th ed. Philadelphia, PA:
Lippincott Williams & Wilkins, 2006:261.
2. Lindholm ML, Träff S, Granath F, et al. Mortality within 2 years after surgery in relation to low intraoperative bispectral index values and preexisting malignant disease. Anesthes Analges. 2009;108(2):508–512.
3. Green D, Paklet L. Latest developments in the peri-operative monitoring of the high risk surgical patient. Int J Surg. 2010;8(2):90–99.
4. Kimberger O, Arnberger M, Brandt S, et al. Goal-directed colloid administration improves the microcirculation of healthy and perianastomotic colon. Anesthesiology.
2009;110(3):496–504.
ADDITIONAL READING
• Cancer Facts and Figures 2010. Atlanta, GA: American Cancer Society, 2010.
• Surveillance, Epidemiology and End Results (SEER) Program of the National Cancer Institute See Also (Topic, Algorithm, Electronic Media Element)
• Insensible fluid losses
• International normalized ratio
• Partial thromboplastin time
• Prothrombin time
CLINICAL PEARLS
• Major bowel resection surgery can require significant blood products and fluid resuscitation in the perioperative period.
• There exists a risk for positioning and surgery-related neuropathies.
• Patients are prone to the occurrence of late DVTs.