What the Anesthesiologist Should Know before the Operative Procedure
There are about 50,000 patients undergoing partial or total nephrectomy surgeries for non–transplant-related indications in the United States annually. Half of those procedures are performed to remove renal tumors. In addition, there are about 6000 individuals per year undergoing nephrectomy for kidney donation.
Nephrectomy is mainly categorized as total and partial nephrectomy. Total nephrectomy is also categorized as radical or simple nephrectomy.
Radical nephrectomy is the treatment of choice for localized renal tumors, involving en bloc removal of the kidney, the ipsilateral surrounding fascia, adrenal gland, and the upper ureter
Simple nephrectomy is performed to remove the kidney only for irreversible kidney damage due to symptomatic chronic infection, obstruction, calculus disease, or severe traumatic injury. Donor nephrectomy, sometimes considered to be a separate category, is a procedure that removes the entire healthy kidney and a portion of ipsilateral ureter from a donor for the purpose of kidney transplantation.
Partial nephrectomy, also called nephron-sparing surgery, is to remove the diseased portion of the kidney anticipating that the remaining portion is still functional. It is widely accepted because of increased detection of renal masses and evidence of improved long-term outcome. This approach is now recommended as the standard of care for kidney masses up to 7 cm, except in the high surgical risk patients, according to the American Urological Association’s recently published guidelines.
b. Surgical procedures
Surgical procedures for nephrectomy include traditional open nephrectomy and minimally invasive surgical procedure. Minimally invasive surgical procedures have recently gained popularity due to the advantages of significantly less trauma, less postoperative pain, shorter hospital stays, and more rapid return to normal activities than conventional open procedures.
i. Open nephrectomy
The surgical approach includes either a transperitoneal incision (extended or bilateral subcostal and thoracoabdominal) or an extraperitoneal incision, depending on the size, location of the tumor, and the patient’s habitus.
ii. Laparoscopic nephrectomy
Laparoscopic nephrectomy is a form of minimally invasive surgery, performed through small incisions with the use of a laparoscope to view the kidney and the surrounding tissues. The laparoscopic view is two dimensional. For access to the kidney, both transperitoneal and retroperitoneal techniques can be used, depending on surgeon’s preference and tumor location. Carbon dioxide is pumped into the surgical site to create space for access to the kidney. The cardiovascular and respiratory effects of pneumoperitoneum and the possibility of acidemia and marked acidosis due to the absorption of carbon dioxide should be the concerns of anesthesia care providers.
iii. Robotic nephrectomy
Over recent years, the introduction and widespread adoption of robotic surgical system changed the view on minimally invasive surgery. When performing robotic surgery, the surgeon sits at a console with a three-dimensional view of the operating field and controls the movements of miniature instruments at the end of robotic arms inserted through several small incisions. The movement of the surgeon’s hands is translated into precise movement of the instruments in the surgical area. Early outcomes obtained with this new technique are comparable with laparoscopic and open nephrectomy as shown in some retrospective studies. There is a lack of long-term follow-up.
1. What is the urgency of the surgery? What is the risk of delay in order to obtain additional preoperative information?
Emergent:Nephrectomy is often not emergent. The physicians have time to optimize the patients’ conditions before operation. However, some post-transplant patients may need emergent nephrectomy to remove a nonfunctional infected kidney.
Urgent: Urgent nephrectomy is rarely needed, unless there is active bleeding from the kidney which cannot be controlled nonsurgically.
Elective: This surgery is never truly elective, since the majority of nephrectomies are for removal of renal tumors and should be performed as soon as the patient’s condition is optimized. Delay of the procedure may cause an increased incidence of tumor metastasis along with the anxiety of the patient and/or family members.
2. Preoperative evaluation
Routine medical clearance is necessary
Patients with minor abnormalities per the American Heart Association/American College of Cardiology (AHA/ACC) Guidelines may proceed to surgery with attention to these medical conditions perioperatively. Minor abnormalities include hypertension and chronic compensated heart failure.
Percutaneous coronary interventions (PCIs) prior to nephrectomy have not been shown to reduce adverse cardiac events. In some instances, PCIs have resulted in an increased incidence of perioperative events, potentially due to the risk of restenosis and thrombosis if antiplatelet therapy is discontinued before the surgery. On the other hand, perioperative bleeding rate may increase if anti-platelet therapy is continued. It is unclear if coronary artery bypass graft before nephrectomy reduces cardiac mortality.
Delay in surgery has not been shown to lead to worse outcome. However, it likely increases the patient’s level of anxiety once the diagnosis of renal tumor is made. The majority of the patients and family members have strong desire to have the surgery done as soon as possible. At the same time, operating on a patient with unstable medical problems is clearly undesirable.
Medically unstable conditions warranting further evaluation include: recent myocardial infarction (MI), unstable arrhythmias, stroke, transient ischemic attack (TIA), and chronic obstructive pulmonary disease (COPD) exacerbation. They warrant further assessment, consultation, work-up and stabilization. Additionally, some of these conditions may also have been the etiology of hypertension and heart failure.
Delaying surgery may be indicated if: unstable medical conditions exist. Otherwise, cardiac clearance and testing may be unnecessary.
3. What are the implications of co-existing disease on perioperative care?
a. Cardiovascular system:
1) Acute/unstable conditions: Patients may have hypotension or arrhythmia due to acute MI/unstable angina. If history, physical examination, or clinical suspicion suggest these conditions, work-up is needed including 12-lead ECG, continuous ECG monitoring, cardiac biomarkers (e.g., troponin), resting echocardiogram (regional wall motion abnormality), and cardiac consultation. Acute ischemia needs to be treated prior to surgery. Severe bradycardia or atrioventricular block may require temporary pacemaker (transcutaneous, esophageal, transvenous). Ventricular tachycardia or ventricular fibrillation needs cardioverter-defibrillator apparatus.
2) Baseline coronary artery disease or cardiac dysfunction: Good clinical history (functional status, changes in exercise tolerance, fatigue), prior ECG or noninvasive stress testing, and consulting patient’s cardiologist or primary care physician if necessary. Outcome studies do not demonstrate a change in therapy or benefit when preoperative cardiac testing is performed in intermediate-risk patients or patients without signs or symptoms of acute ischemia.
Perioperative risk reduction strategies
1) Monitoring–Consider preinduction arterial line. Full perioperative hemodynamic monitoring (CVP, PA line, TEE) may be warranted.
2) Gols of mangement–Optimize oxygen supply-and-demand ratio.
a. Increase O2 supply
FiO2–Consider using high FiO2 to achieve SpO2 100%.
Hemoglobin–Consider transfusion to increase oxygen carrying capacity.
Heart rate–Consider reducing heart rate with beta blockers or calcium channelblockers in order to increase time in diastole, as left ventricle isperfused only in diastole.
Coronary perfusion pressure–Optimize coronary perfusion pressure, which equals diastolic pressure minus left ventricular diastolic pressure.
Avoid hypercarbia–Hypercarbia may cause intense sympathetic discharge and significant increase in plasma catecholamine levels. When PaCO2 level reaches 56 to 65 mm Hg, cardiac oxygen demand significantly increases, while cardiac filling time is shortened, as indicated by the increase in the tension time index and decrease in the diastolic time. This signifies a relative myocardial underperfusion.
b. Reduce O2 demand
Heart rate–Beta blockers or calcium channel blockers reduce heart rate and oxygen consumption.
Contractility–Beta blockers and calcium channel blockers reduce contractility and O2 demand.
Afterload–Need to be optimized. Increased afterload (systemic vascular resistance, SVR) raises the resistance that the heart needs to pump against, and hence myocardial oxygen consumption (pressure work) increases. However, if afterload is too low, it may jeopardize coronary perfusion pressure.
Patients with pulmonary diseases are at high risk of postoperative lung dysfunction including pneumonia after general anesthesia. Perioperative hypoxia may result from pulmonary emboli, atelectasis, pulmonary congestion (and effusion) due to chronic heart failure, or consolidation due to infection. Additionally increase in age leads to higher alveolar-arterial gradient of oxygen due to an increase in closing volumes and intra-pulmonary shunt.
1) Preoperative evaluation: Careful clinical history including pack per year smoking history, frequency of exacerbations, recent or current exacerbation, oxygen requirements, current medication regimen, and available recent studies (spirometry). Unless acute exacerbation is suspected. pulmonary testing may unnecessarily delay surgery.
2) Perioperative risk reduction strategies:
Continue current pulmonary medications perioperatively; consider starting nebulizer and/or steroid therapy if appropriate (e.g., severe disease).
Pursue maneuvers intraoperatively to optimize gas exchange.
Epidural analgesia is highly desirable. Such technique not only provides adequate pain control postoperatively, but also significantly reduces the requirement of systemic narcotic use and its related complications.
If general anesthesia is preferred, consider using inhalation agents for bronchodilation.
During maintenance, keep patient well anesthetized to avoid bronchospasm, adjust I:E ratio to allow for adequate expiratory time to minimize auto-PEEP, use PEEP to reduce atelectasis and shunting. However, be cautious not to rupture an emphysematous bleb.
Postoperation, apply appropriate pulmonary toilet, incentive spirometry, nebulizer and steroid therapy if necessary.
Reactive airway disease (Asthma)
1) Preoperative evaluation: Assess severity of disease including frequency of exacerbations, triggers (cold weatehr, environmental, medications, and upper respiratory infections), routine and rescue medications, recent oral or IV steroid therapy, emergency room visits, hospitalizatons, ICU admissions and intubations.
2) Perioperative risk reduction strategies: Continue control medications perioperatively and consider a course of nebulizer and/or steroid therapy if patient appears to have moderate to severe disease. Perioperative systemic corticosteroids are recommended for persistent symptoms if the peak flow rate and FEV1 are less than 80% predicted or previous best. As with COPD, postoperative epidural anagesia is highly recommended. The management of general anesthesia should be similar to that with COPD for induction, maintenance, and postoperative care in order to avoid bronchospasm.
Patients undergoing nephrectomy often have renal function insufficiency. Systematic evaluation of renal function prior to nephrectomy is absolutely necessary.
1) Assess volume status. History of oral intake, vital signs, skin turgor, mucus membranes, urine output, and lab values are important information. Patients need to be appropriately rehydrated prior to induction of general anesthesia or neuraxial block. Because renal insufficiency is common in this population, urine output may not be a good measure to assess the volume status.
2) Check urinalysis results. Hematuria and the presence of casts, bacteria, and white cells may be found on microscopy. Urinary specific gravity is an index of renal tubular function. The ability to excrete concentrated urine (specific gravity >1.030) indicates good tubular function, whereas fixed urinary osmolality at that of plasma (specific gravity 1.010) is indicative of renal disease. Proteinuria greater than 150 mg per day is abnormal and usually indicates severe glomerular damage. However, it may also occur due to abnormally increased concentrations of plasma proteins. Glucosuria usually indicates the presence of diabetes mellitus. A full blood count may reveal anemia (normocytic, normochromic), either due to excessive hematuria, or reduced production of erythropoietin.
3) Plasma creatinine and urea concentrations provide good information about general renal function. Creatinine clearance can be used to specifically measure glomerular filtration rate (GFR).
4) Serum electrolyte concentrations and arterial blood gas may reveal a metabolic acidosis or electrolyte imbalance.
5) If the nephrectomy is to remove the only functional kidney, postoperation hemodialysis should be arranged before the day of surgery.
Perioperative risk reduction strategies
1) Avoid factors that can compromise renal function
Nephrotoxic drugs (aminoglycosides, NSAIDs)
Hypotension. Excision of large renal masses may result in major hemorrhage and the use of invasive monitoring is recommended. Large-bore intravenous access is mandatory because of the risk of massive bleeding and potential massive transfusion.
Dehydration. Maintain intraoperative fluid balance, ensuring not to overload the patient with fluid and at the same time, not to compromise the renal perfusion. Patients with end stage renal disease may benefit from central venous pressure monitoring to guide fluid requirement.
Sepsis. Infection should be treated promptly.
2) Protect renal function
Administration of dopamine,diuretics, calcium channel blockers, angiotensin-converting enzyme inhibitors, and hydration may be considered. However, a recent Cochrane database review concludes that there is no evidence that any of these interventions protect the kidneys from damage.
For partial nephrectomy, optimizing renal function of the remaining portion of kidney is critical. Besides keeping warm ischemia time as short as possible, a few other techniques are also used. Mannitol (12.5 g) is frequently given before clamping renal artery. Many surgeons also give mannitol (12.5 g) before harvesting the kidney from donor. However, outcome studies on the protective effect of mannitol remain to be conducted.
3. Select anesthetic drugs
The termination of action of most anesthetic drugs is due to redistribution and metabolism. Biotransformation of these drugs usually results in pharmacologically inactive forms of the parent compound which are water soluble and excreted through kidney. Some nondepolarizing muscle relaxants (except atracurium and cisatracurium) are largely eliminated by the kidney, and dose reduction is required in patients with impaired renal function. Succinylcholine (suxamethonium) administration does cause a rise in serum potassium, which may be dangerous in patients who have hyperkalemia.
Preoperative evaluation: Assess the likelihood of perioperative aspiration. Particular attention is needed to ask if the patient has a full stomach and/or symptom of gastroesophageal reflux disease.
Perioperative risk reduction strategies for pulmonary aspiration: Consider awake orogastric tube to empty stomach, as well as promotility agents, H2-blockers, and antacid medications as appropriate, prior to general anesthesia or neuraxial blocks.
TIA and stroke are unstable medical conditions that need to be resolved prior to surgery.
Preoperative evaluation: Detailed history should be taken and thorough neuro-exam should be performed (loss of consciousness, history of cerebrovascular disease, neurological deficits), and if necessary further workup (CT or MRI, carotid Doppler, echocardiogram, or neurology consult) should take place prior to surgery.
A history of carotid disease may necessitate higher blood pressures in order to maintain adequate cerebral perfusion. Arterial line may be needed. Regional anesthesia is not contraindicated; however, consider epidural placement with gradual bolusing to avoid abrupt sympatholysis and allow time for treating hypotension. Consider phenylephrine infusion.
Diabetes mellitus is a common cause of renal insufficiency, and an appropriate plan should be made for the management of such patients in the perioperative period.
Preoperative evaluation should focus on assessing organ damage and control of blood sugar. The glycosolated hemoglobin level is not influenced by fasting and can be used to assess how well the disease is controlled. The American Diabetes Association recommends target glycosolated hemoglobin of less than 7%.
Perioperative risk reduction strategies
1) If the patient is insulin dependent, glucose level should be determined every 2 hours intraoperatively.
2) Avoid hypoglycemia and marked hyperglycemia. The American College of Endocrinologists’ position statement recommends a target fasting glucose level of less than 110 mg/dL in non–critically ill hospitalized patients. However, data regarding the influence of intensive insulin therapy on outcome after major surgery are relatively scarce. Some studies revealed that tight glucose control may increase the risk of hypoglycemia and relate with a higher morbidity and mortality in ICU patients.
4. What are the patient's medications and how should they be managed in the perioperative period?
The anesthesiologist should obtain a drug history from the patient, including vitamins, herbs, and supplements before surgery, and have knowledge of these medications on the classification, indication, and common side effects. General rule accepted during perioperative management is not altering preoperative drug therapy with exception pertaining to (1) MAOIs, (2) anticoagulants and fibrinolytic drugs (e.g., clopidogrel [Plavix]) if surgical hemostasis is needed, (3) nicotinic acid, (4) dosage adjustments for insulin and corticosteroids, (5) ACE inhibitors and receptor antagonists (angiotensin II receptor blocking drugs), and (6) drugs for erectile dysfunction (i.e., sildenafil [Viagra], vardenafil [Levitra], tadalafil [Cialis], or similar drugs).
Suggestions for commonly used medications
Antihypertensive medications—Continue on the day of the operation or procedure.
Diuretics—Continue on the day of the operation or procedure.
Cardiac medications (e.g., digoxin)—Continue on the day of the procedure.
Antidepressant, antianxiety, and psychiatric medications—Continue on the day of the operation or procedure.
Thyroid medications—Continue on the day of the operation or procedure.
Birth control pills—Continue on the day of the operation or procedure.
Eye drops—Continue on the day of the operation or procedure.
Heartburn or reflux medications (e.g., Prilosec, Zantac)—Continue on the day of the operation or procedure.
Narcotic pain medications—Continue on the day of the operation or procedure.
Antiseizure medications—Continue on the day of the operation or procedure.
COX-2 inhibitors—Continue on the day of the operation or procedure unless the surgeon specifies (usually concerned about bone healing).
NSAIDs—Usually continue on the day of the operation or procedure.
Vitamins, iron, Premarin—Discontinue on the day of the operation or procedure.
Topical medications (e.g., creams and ointments)—Discontinue on the day of the operation or procedure.
Oral hypoglycemic drugs—Discontinue on the day of the operation or procedure.
Insulin—For all patients, discontinue all regular or combination (70/30 preparations) insulin on the day of the operation or procedure. Type 2 diabetics should discontinue all insulins of any type. Type 1 diabetics should take a small amount (usually a third) of their usual am long-acting insulin (e.g., Lente or NPH) on the day of the operation or procedure. Type 1 diabetics should not take any short-acting insulin, such as regular insulin, on the day of the procedure. Patients with an insulin pump should continue their basal rate only.
Viagra or similar drugs—Discontinue 36 hours before surgery only when they are not being used for pulmonary hypertension
Herbals and nonvitamin supplements—Discontinue 7 days before surery.
MAOIs (monoamine oxidase inhibitors)—Patients taking these antidepressant medications need an anesthesia consultation before surgery (preferably 3 weeks before surgery).
a. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
Beta blockers—Patients on beta blockers should be continued perioperatively with a goal heart rate less than 70 bpm, which may cause hypotension from reduced contractility and reduction in heart rate. Starting beta blockers in intermediate- and high-risk cardiac patients may reduce adverse cardiac events perioperatively. However, studies have not elucidated the ideal length of therapy, if a particular beta blocker is more effective, or how long postoperatively a patient should continue therapy. Additionally, starting beta blockers perioperatively may be associated with an increased risk of stroke (thought to be due to hypotension) and death.
Statins—Patients on statins should be continued perioperatively. Discontinuation is associated with increased risk of adverse cardiac events and mortality. Starting statins in high risk cardiac patients may reduce adverse cardiac events. However, studies are still looking at the length of therapy needed, dosing, titration parameters, and how long to continue postoperatively.
Aspirin— Restart as soon as possible postoperatively. If a coronary stent is the indication for aspirin, increased vigilance for acute myocardial ischemia and infarction is warranted.
Clopidogrel—Patients may be on platelet glycoprotein IIB/IIIA receptor inhibitors for coronary stents. If so, evaluate for drug eluting versus bare metal stent, as well as the implant date. Discussion with surgeon and cardiologist may be necessary to optimize management and balance risk of thrombosis/restenosis versus increased risk of bleeding. It is also important to know when to restart antiplatelet aggregation agents. Taking antiplatelet aggregation drugs is a contraindication for neuraxial blocks.
b. What should be recommended with regard to continuation of medications taken chronically?
Cardiac: Please see above for beta blockers, statins, aspirin, clopidogrel.
Pulmonary: Continue the medications (inhaled beta agonists, leukotriene inhibitors, inhaled steroid, and oral therapy) perioperatively. The patient may need additional therapy (e.g. inhaled beta agonists as a nebulizer, steroid course) if with moderate or severe COPD or asthma.
Renal: Usually all the medications continue, unless postoperative hemodialysis is anticipated.
Neurologic: Patients may be on antiplatelet therapy for cerebrovascular disease and discussion with primary/surgical team should take place to assess risk of thrombosis/restenosis versus increased risk of bleeding. Antiepileptic and anti-Parkinson medications should continue perioperatively.
Antiplatelets: Please see above for aspirin and clopidogrel. Once again, risk of restenosis/thrombosis needs to be balanced with increased risk of bleeding from surgical site.
Anticoagulants: Many patients take warfarin for chronic atrial fibrillation and/or peripheral vascular diseases. Discontinuation of warfarin is often necessary. When warfarin is discontinued, anesthesia care providers need to discuss with surgical team and ensure (1) INR is followed; (2) whether temporary heparin infusion is needed; and (3) when warfarin will be restarted. If INR is greater than 1.3, epidural catheter placement is not advised.
Psychiatric: Continue antidepressant and antianxiety medications perioperatively. However, lithium is usually discontinued 2-3 days prior to the surgery.
c. How To modify care for patients with known allergies?
Any known or potential trigger agents should be identified and avoided.
d. 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.
A list of drugs containing latex bottle tops should be available in every pharmacy and these drugs, if used, should have their tops pried open using a bottle opener. All personnel should use nonlatex gloves, tourniquets, and catheters, and all anesthesia equipment must be latex free. All drugs needed for the treatment of an anaphylactic reaction should be at hand before the start of the case. No special pretreatment is required if the above steps are followed.
e. Does the patient have any antibiotic allergies
If there is beta-lactam allergy, drug of choice is vancomycin or clindamycin.
f. Does the patient have a history of allergy to anesthesia?
Malignant hyperthermia (MH)
Documented: Avoid all trigger agents such as succinylcholine and inhalational agents:
a). Proposed general anesthetic plan: Prepare the anesthetic machine to rid it of trace anesthetic gases, change the soda lime canister and circuitry and remove all vaporizers for added safety.
b). Ensure MH cart available: Check that sufficient amout of dantrolene is available.
Family history or risk factors for MH: If a close relative had a positive contracture test, then it not unreasonable to treat the patient as an MH-susceptible patient. The fact that the patient may have had previous uneventful anesthetics is no guarantee that MH is ruled out completely.
Local anesthetics/ muscle relaxants: Any known agent the patient is allergic to should be avoided.
5. What laboratory tests should be obtained and has everything been reviewed?
Hemoglobin levels: Patients are frequently dehydrated and thus hemoglobin must be evaluated in light of volume status (hypovolemic, euvolemic, or hypervolemic).
Indications for transfusion:
The decision to transfuse is based upon comorbidities/end organ damage, signs or symptoms of inadequate oxygen carrying capacity, presence of anaerobic glucose metabolism as seen by lactic acidosis, continued blood loss, blood pressure unresponsive to vasopressors, and coagulation status.
Patients with end organ disease (cerebral, cardiac, pulmonary, and renal) are often transfused below euvolemic hemoglobins of 10 g/dL, to optimize oxygen carrying capacity.
Packed RBC transfusion is indicated for inadequate oxygen carrying capacity. Clinical assessment of cerebral and cardiac functions includes mental status, drowsiness, angina, arrhythmias, ECG changes, and hypotension.
Potassium—Patients on potassium wasting diuretics, or hemodialysis may have abnormalities. Patients with end stage renal disease and on hemodialysis may require nephrectomy due to recurrent urinary tract infections. This population often needs hemodialysis either the date prior the surgery or in the early morning of the surgical day in order to correct the imbalance of electrolytes and optimize the volume status for the surgery.
Sodium—Dehydration causes elevation of sodium levels.
BUN/creatinine—Ratio greater than 20:1 often suggests hypovolemia.
If INR is greater than 1.3, epidural catheter placement is not advised.
Platelet count: Because epidural analgesia is quite beneficial in nephrectomy, platelet count should be known prior to epidural catheter placement. Platelet count less than 100,000 is often considered as a cut off for epidural catheter placement.
Imaging: Include stress tests, renal imaging, etc. CT scan is often available. Reviewing the imaging strengths understanding of anatomical abnormality. Such information is useful to plan intraoperative monitoring, intravenous access and potential massive transfusion.
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
Some anesthesia care providers may choose regional anesthesia (spinal, epidural, combined spinal-epidural) with sedation. However, given the current literature, our preferred choice for open surgery of either radical or partial nephrectomy is general anesthesia with low thoracic epidural catheter placement if not contraindicated. In this patient population, general anesthesia is very beneficial considering the length of surgery and the lateral positioning with flexion.
Because the large incision is just below the rib cage, postoperative pain control is often challenging without epidural analgesia. Patient-controlled intravenous analgesia could be problematic, particularly for elderly patients. Large doses of narcotics may be needed in order to achieve adequate pain control, which could cause undesirable side effects including respiratory drive suppression, limited coughing ability, and smaller tidal volumes. It may also be associated with a high incidence of postoperative pneumonia. If the epidural is not planned for robotic or laparoscopic surgery and the case is converted to open procedure intraoperatively, the epidural catheter can be placed after wake up either in the operating room or in recovery room.
We often start remifentanyl infusion at ~30-45 min of estimated time prior to extubation, in order to wean off propofol or wash out inhalation agents. Remifentanyl not only significantly reduces the emergence time but also minimizes the likelihood of coughing and bucking during extubation. This technique is very useful if the measure is taken to prevent intraoperative awareness.
Can be performed with sedation. But it is rarely used without combination with general anesthesia for nephrectomy in the United States.
Patients with pulmonary disease may benefit from maintaining spontaneous breathing.
May reduce incidence and severity of postoperative cognitive disorder in the elderly.
Excellent pain control may preclude need for intravenous narcotics and minimize their side effects.
Potentially reduces incidence of MI and postoperative hypoxia.
Contraindiated in patients taking clopidegrol, warfarin, or in patients with coagulopathy. Follow American Society of Regional Anesthesia guidelines [ASRA GUIDELINES[.
Positioning. Lateral decubitus position with flexion may not be tolerated by an awake patient. For patients who have spinal abnormality and/or back pain, testing the tolerance of positioning should be peformed prior to induction of anesthesia in order to minimize the complications of the flexion on lateral decubitus position.
Patient or family refusal may preclude the catheter placement.
Sympatholysis may not be tolerated (e.g., in coronary artery disease, aortic stenosis, cerebrovascular disease).
Does not necessarily preclude need for invasive monitors such as arterial line, CVP, which need to be placed in awake/sedated patient.
3) Other issues
Need to plan postopertive anticoagulation therapy with the surgical team. Patients may be started on low molecular weight heparin (LMWH). However, removal of catheter needs to be timed appropriately. If LMWH is used BID 0.5 mg/kg, insertion or removal of catheter need to wait until 12 hours from prior dose, and hold the next dose for 2 hours after the catheter is removed.
Rib nerve block
May be considered in patients who are not a feasible candidate for epidural analgesia. It becomes more and more frequent that surgery initiated as eitehr laparoscopic or robotic is converted to open procedure intraopertively due to technique difficulties. Such patients often do not have but need epidural analgesia postoperatively. Rib nerve block is an option for postoperative pain control.
Can be performed in patients using antiplatelet therapy, with spinal anatomy disease, or having other contraindications to neuraxial block.
Can be performed as a single shot, or a catheter may be placed.
No need to hold anticoagulants.
Can have patchy block.
The quality of postoperation pain control may be less satisfactory compared with epidural analgesia.
b. General Anesthesia
1) Providing adequate sedation, analgesia, amnesia, and muscle relaxation.
2) Secured airway, ensuring positive pressure ventilation, reduction of intraoperative aspiration, and allowance of PEEP, which is required for laparoscopic nephrectomy.
3) Better management of combative or delirious patients.
4) Tolerance of positioning.
1) Inability to communicate with the patient.
2) Frequent postoperative nausea and vomiting as side effects of general anesthesia.
3) Swings in hemodynamics, may increase postoperative cognitive disorder in the elderly.
4) Positive-pressure ventilation used during general anesthesia can reduce cardiac output, and more likely to cause pulmonary complications.
5) Prolonged wake-up phase from anesthesia itself – sometimes long hang-over effect.
Other issues: Need to plan postoperative analgesia especially in open nephrectomy.
Airway concerns: Particularly for patients with a history of previous difficult intubation and/or mask ventilation, and for patients whose airway assessment is not favorable for intubation.
c. Monitored Anesthesia Care
Not an option for anesthesia of nephrectomy.
7. What prophylactic antibiotics should be administered?
Based upon recommendations published in October 2009, antibiotic prophylaxis for nephrectomy is cefazolin, cefuroxime, or vancomycin. If there is beta-lactam allergy, the drug of choice is vancomycin or clindamycin. Choice of antibiotics should be reviewed to determine if there were recent changes in the recommendations since October 2009.8. What do I need to know about the surgical technique to optimize my anesthetic care?
The tumor is often large and extends into the vena cava in ~5% of patients. Surgeons may have difficulty in obtaining access to the renal vein and arteries. If the tumor invades or is close to the major vessels, such as the inferior vena cava, significant amount of blood loss may occur. Therefore, preparation for massive blood transfusion should be done prior to the operation. Complete occlusion of the inferior vena cava or tumor embolization may occur intraoperatively. Therefore, the exact extent of the lesion must be identified preoperatively. On occasion, cardiopulmonary bypass and circulatory arrest have been used to resect the tumor with extensive caval invasion.
If the location of the tumor is adjacent to diaphragm, surgeons may have to perform partial resection of the diaphragm. In such a case, chest tube may be needed. If chest tube is not inserted, the surgeon has to optimize the insufflations of the lung on the surgical site prior to closure of diaphragm. The commonly used approach is performance of the Valsalva maneuver at the closure of the diaphragm.
i. Warm ischemia time
Temporary occlusion of the renal artery is often necessary for partial nephrectomy, and warm ischemia time is one of the major factors affecting postoperative renal function of the remaining portion of the kidney. A wide range of tolerable warm ischemia time (30–55 minutes) has been suggested. However, longer than 20 minutes of ischemia is associated with significantly decreased postoperative GFR.
When the anticipated period of intraoperative renal ischemia is longer than 30 minutes, additional protective measures are indicated to minimize the insult to the kidney. Local hypothermia is the most effective and commonly employed method for protecting the kidney against ischemic injury. Both animal and human studies have shown that a temperature of 20~25°C provides complete renal protection from arterial occlusion for up to 3 hours.
Another aspect that the anesthesia care provider has to remember is to time the warm ischemia and keep surgeons informed. Once it passes 20 minutes, surgeons often need to work hard and limit the warm ischemia time to less than 30 minutes.
There are numerous adjunctive hemostatic agents and energy devices used during partial nephrectomy. The most consistently beneficial adjuncts include oxidized methylcellulose gauze, gelatin matrix thrombin sealants, and fibrin glues. Argon beam coagulator is also widely used for hemostasis. Despite the advance in technology of hemostasis, the estimated blood loss is still a concern. However, recent reports stated that the mean intraoperative blood loss during partial nephrectomy is less than 200 mL.
9. What can I do intraoperatively to assist the surgeon and optimize patient care?
a. Positioning: lateral decubitus and flexion position or kidney rest position
1) Both laparoscopic and open nephrectomies are usually performed at a lateral decubitus position with flexion. Such a position not only requires careful padding, securing the arms, neck, and head, but also needs extra concern to the significant cardiorespiratory changes, including decreases in thoracic compliance and functional residual capacity. Dependent atelectasis is common and may lead to hypoxemia.
2) Modern operating room table has a controller to precisely indicate the degree of the flexion. However, when the table is flexed, it should be done with particular attention to the alignment of the cervical spine relative to the thoracic spine.
3) Since nephrectomy usually lasts about 3 to 4 hours, the patient’s ear at the dependent side should not be pressed in order to avoid the ischemia of the ear. Intermittent re-positioning and massage of the head and face of the dependent side are desirable.
4) The arm of the independent side normally is supported with an arm holder and kept from pressing the dependent arm. The upper arm should maintain at a flexion position not greater than 90 degrees. The dependent arm should be padded and secured on an arm board. The elbow of the dependent side is a common pressure point that needs to be well padded in order to minimize ulnar nerve injury.
5) Lower extremities are protected in a way that independent leg is not directly pressing on dependent leg by placement of a pillow between legs. Both legs are massaged with pneumatic boots to reduce the incidence of deep vein thrombosis.
6) As the upper body could directly press on the dependent shoulder, an axillary roll is usually used to release the pressure on axillary nerve and vessels. Some space should be left between the axillary roll and the upper armpit of the dependent side. It is also desirable to use a bean bag. Before the bean bag is actively deflated, both anesthesia team and surgical team should re-check the position and ensure all the pressure points are well padded and not overpressed.
7) Safety belt and/or tape are also necessary to prevent patient from rolling to sides prior to completion of surgery. Actively deflated bean bag is also useful to maintain the patient in lateral decubitus position.
b. Fluid balance
1) Fluid replacement to compensate fluid deficit due to bowel preparation and fasting should take place early during surgery, particularly in elderly patients. Patient with end-stage renal disease who has had recent dialysis may likewise be fluid depleted preoperatively. Fluid replacement should be done with caution to avoid fluid overload.
2) In order to keep fluid balance intraoperatively, evaporative loss from an open abdomen (10-30 mL/kg/h) and third space loss to bowel, omentum, and retroperitoneum must be taken into account. Volume of blood loss is normally replaced with crystalloid at ratio of 1:3 if hemoglobin concentration is above 10 g/dL.
3) Potassium-containing fluids should be avoided in those with impaired renal function. Colloid and packed red blood cells should be used to compensate for hemorrhage. Patients may have preexisting chronic anemia, in which case they will tolerate less blood loss than nonanemic patients. Other blood products such as fresh frozen plasma, cryoprecipitate, and platelets may be required in the face of coagulopathy. When massive transfusion is carried out, ionized calcium should be frequently monitored and ionized hypocalcemia should be corrected.
4) Urine output usually decreases during surgery, particularly when the patient is in lateral flexion position. Postoperatively, a urine output of 0.5-1.0 mL/kg/h should be the aim for those with normal renal function. Patients with impaired renal function are more problematic with regard to fluid balance. Anuric patients who are reliant on dialysis should ideally have strict attention paid to their fluid balance, and only have losses and maintenance requirements replaced. Dialysis may be used postoperatively if there is an element of fluid overload.
10. What are the most common intraoperative complications and how can they be avoided/treated?
Hemorrhage The kidney is a highly vascular organ; thus, hemorrhage is a real risk. Bleeding can occur from renal artery, aberrant arteries, or inferior vena cava. The risk is higher in the presence of malignancy or inflammation. Techniques to reduce the need for blood transfusion such as acute normovolemic hemodilution and antifibrinolytic drugs may be used where appropriate. The use of Cell Saver for renal tumor is debatable. Secondary hemorrhage occurring in the postoperative period is rare but may necessitate laparotomy. Partial nephrectomy has higher risk of blood loss compared to total nephrectomy due to a large fresh resection area in the remaining renal tissue. Several techniques are frequently used, including coagulation agents and argon beam.
Cardiac complications Myocardial oxygen supply/demand ratio should be optimized perioperatively. The need for invasive monitoring should be assessed. Postoperatively, shivering should be avoided and pain control should be optimized. Postoperative pain can trigger a stress response leading to tachycardia, hypertension, increased oxygen demand, and myocardial ischemia. Beta-blockers and statins should be continued if previously used. Anticoagulants for coronary artery stents should be resumed when appropriate. Telemetry or intensive care should be considered.
Pneumothorax Damage may occur to the pleura or diaphragm because the kidney lies in close proximity to the lungs. This is usually visible at open procedure and a repair can be done before completion of the surgery. However, a high index of suspicion, particularly during laparoscopic surgery, must be maintained. Rapidly developing difficult ventilation and/or desaturation should be fully investigated and surgeons should be informed of any concerns. Any pneumothorax may rapidly progress to a tension pneumothorax with the use of intermittent positive pressure ventilation and can cause severe hemodynamic instability. Postoperative chest x-ray is routinely performed to rule out pneumothorax.
Laparoscopic surgery may result in significant hypercarbia and acidosis from the carbon dioxide used to create the pneumoperitoneum, particularly in prolonged operations. High intra-abdominal pressure interferes with ventilation and obstructs venous return, leading to significant hemodynamic alterations.
Injury may occur to the small or large bowel, necessitating primary repair or a colostomy formation.
11. If the patient is intubated, are there any special criteria for extubation?
Prior to extubation, the patient should be awake, alert, and able to respond to command and generate adequate tidal volume. Majority of the patients are extubated at the completion of surgery, and postoperative mechanical ventilation is not indicated. Occasionally, patients with severe respiratory insufficiency may need short-term ventilatory support postoperatively.
For those who receive laparoscopic or robotic nephrectomy, there is a risk that subcutaneous emphysema may extend along the tissue planes around the neck and cause airway obstruction after extubation. This complication should be kept in mind before extubation of these patients.
12. Postoperative management:
What analgesic modalities can I implement?
Intravenous, epidural, or intrathecal morphine or rib nerve block techniques. Narcotic dosage may need to be adjusted appropriately for elderly. If intrathecal or epidural morphine or patient-controlled analgesia is given, postoperative monitoring with pulse oximeter should be kept for 24 hours.
What level bed acuity is appropriate?
The choice of floor, telemetry, and step down or ICU admission depends on patients’ preoperative comorbidities, intraoperative course, and hospital resources.
What are common postoperative complications and their prevention and treatment?
Postoperative complications occur in ~10%-20% of patients who received nephrectomy and majority of the complications are minor. Nephrectomy for malignant disease has a significantly higher rate of complications than operations for benign conditions, especially hemorrhage and pneumonia are more frequent. Reoperation is carried out in 3.0% of the cases. Overall mortality rate (<30 days) is 3.1%.
What's the Evidence?
Van Hautea, Wim, Gavazzib, Andrea, Dasgupta, Prokar. “Current status of robotic partial nephrectomy”. Curr Opin Urol. vol. 20. 2010. pp. 371-4. (An overview of the progress and main concerns in robotic nephrectomy.)
Eisenberg, Manuel S, Brandina, Ricardo, Gill, Inderbir S. “Current status of laparoscopic partial nephrectomy”. Curr Opin Urol. vol. 20. 2010. pp. 365-70. (An overview of the progress and main concerns in laparoscopic partial nephrectomy.)
Conacher, ID, Soomro, NA, Rix, D. “Anaesthesia for laparoscopic urological surgery”. Br J Anaesth. vol. 93. 2004. pp. 859-64. (Complications of the surgery and postoperative management.)
O’Hara, Jerome F, Cywinski, Jacek B., Monk, Terri G, Barash, Paul G, Cullen, Bruce F, Stoelting, Robert K. “The renal system and anesthesia for urologic surgery”. Clinical anesthesia. 2006. pp. 1014-37. (Preoperative evaluation and perioperative management of patients undergoing urological surgery.)
Cousins, J, Howard, J, Borra, P. “Principles of anaesthesia in urological surgery”. BJU Int. vol. 96. 2005. pp. 223-9. (An overview of principles of anesthesia in urological surgery including details regarding preoperative medication management, patient positioning during surgery, and choice of anesthetic methods.)
Malhotra, Vinod, Sudheendra, Vijayendra, O’Hara, Jerome, Diwan, Sudhir, Miller, RD. “Anesthesia for the renal and genitourinary systems”. Anesthesia. 2009. pp. 1934-59. (Preparation of the patient for surgery, complications during surgery, and management of the postsurgical period.)
Zacharias, M, Gilmore, IC, Herbison, GP, Sivalingam, P, Walker, RJ. “Interventions for protecting renal function in the perioperative period”. Cochrane Database Syst Rev. vol. 8. 2008. pp. CD003590(Evaluation of interventions currently used to protect renal function.)
Wagener, G, Brentjens, TE. “Anesthetic concerns in patients presenting with renal failure”. Anesthesiol Clin. vol. 28. 2010. pp. 39-54. (Preoperative evaluation of renal function and methods used to protect renal function.)
Van Kuijk, JP, Schouten, O, Flu, WJ, den Uil, CA, Bax, JJ, Poldermans, D. “Perioperative blood glucose monitoring and control in major vascular surgery patients”. Eur J Vasc Endovasc Surg. vol. 38. 2009. pp. 627-34. (Suggestions on perioperative blood glucose control perioperatively.)
Beisland, C, Medby, PC, Sander, S, Beisland, HO. “Nephrectomy: indications, complications and postoperative mortality in 646 consecutive patients”. Eur Urol. vol. 37. 2000. pp. 58-64. (Postoperative complications after nephrectomy.)
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- What the Anesthesiologist Should Know before the Operative Procedure
- 1. What is the urgency of the surgery? What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- a. Cardiovascular system:
- b. Pulmonary:
- c. Renal:
- d. GI:
- e. Neurologic:
- f. Endocrine:
- 4. What are the patient's medications and how should they be managed in the perioperative period?
- a. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
- b. What should be recommended with regard to continuation of medications taken chronically?
- c. How To modify care for patients with known allergies?
- d. 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.
- e. Does the patient have any antibiotic allergies
- f. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
- b. General Anesthesia
- c. Monitored Anesthesia Care
- 7. What prophylactic antibiotics should be administered?
- 9. What can I do intraoperatively to assist the surgeon and optimize patient care?
- 10. What are the most common intraoperative complications and how can they be avoided/treated?
- 11. If the patient is intubated, are there any special criteria for extubation?
- 12. Postoperative management: