Aneasthesia Pearls April 2014

ANAESTHESIA PEARLS

Obstetric Anesthesia

Practice Guidelines for Obstetric Anesthesia
An Updated Report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia
Practice Guidelines for Obstetric Anesthesia
Aspiration Prophylaxis
Oral intake of modest amounts of clear liquids may be allowed for uncomplicated laboring patients.
The uncomplicated patient undergoing elective cesarean delivery may have modest amounts of clear liquids up to 2 h before induction of anesthesia.
The volume of liquid ingested is less important than the presence of particulate matter in the liquid ingested.
Patients with additional risk factors for aspiration (e.g., morbid obesity, diabetes, difficult airway) or patients at increased risk for operative delivery (e.g., nonreassuring fetal heart rate pattern) may have further restrictions of oral intake, determined on a case-by-case basis.
Solid foods should be avoided in laboring patients.
Patients undergoing elective surgery (e.g., scheduled cesarean delivery or postpartum tubal ligation) should undergo a fasting period for solids of 6–8 h depending on the type of food ingested (e.g., fat content).
Before surgical procedures (i.e., cesarean delivery, postpartum tubal ligation), practitioners should consider timely administration of nonparticulate antacids, H2 receptor antagonists, and/or metoclopramide for aspiration prophylaxis.
Anesthetic Care for Labor and Delivery
Neuraxial Techniques: Availability of Resources
When neuraxial techniques that include local anesthetics are chosen, appropriate resources for the treatment of complications (e.g., hypotension, systemic toxicity, high spinal anesthesia) should be available.
If an opioid is added, treatments for related complications (e.g., pruritus, nausea, respiratory depression) should be available.
An intravenous infusion should be established before the initiation of neuraxial analgesia or anesthesia and maintained throughout the duration of the neuraxial analgesic or anesthetic.
Administration of a fixed volume of intravenous fluid is not required before neuraxial analgesia is initiated.
Timing of Neuraxial Analgesia and Outcome of Labor
Neuraxial analgesia should not be withheld on the basis of achieving an arbitrary cervical dilation, and should be offered on an individualized basis when this service is available.
Patients may be reassured that the use of neuraxial analgesia does not increase the incidence of cesarean delivery .
Neuraxial Analgesia and Trial of Labor after Previous Cesarean Delivery
Neuraxial techniques should be offered to patients attempting vaginal birth after previous cesarean delivery.
For these patients, it is also appropriate to consider early placement of a neuraxial catheter that can be used later for labor analgesia or for anesthesia in the event of operative delivery.
Early Insertion of Spinal or Epidural Catheter for Complicated Parturients
Early insertion of a spinal or epidural catheter for obstetric (e.g., twin gestation or preeclampsia) or anesthetic indications (e.g., anticipated difficult airway or obesity) should be considered to reduce the need for general anesthesia if an emergent procedure becomes necessary.
For these patients, it is also appropriate to consider early placement of a neuraxial catheter that can be used later for labor analgesia or for anesthesia in the event of operative delivery.
In these cases, the insertion of a spinal or epidural catheter may precede the onset of labor or a patient’s request for labor analgesia.
Continuous Infusion Epidural (CIE) Analgesia
The selected analgesic/anesthetic technique should reflect patient needs and preferences, practitioner preferences or skills, and available resources.
CIE may be used for effective analgesia for labor and delivery.
When a continuous epidural infusion of local anesthetic is selected, an opioid may be added to reduce the concentration of local anesthetic, improve the quality of analgesia, and minimize motor block.
Adequate analgesia for uncomplicated labor and delivery should be administered with the secondary goal of producing as little motor block as possible by using dilute concentrations of local anesthetics with opioids.
The lowest concentration of local anesthetic infusion that provides adequate maternal analgesia and satisfaction should be administered .
Single-injection Spinal Opioids with or without Local Anesthetics
Single-injection spinal opioids with or without local anesthetics may be used to provide effective, although time-limited, analgesia for labor when spontaneous vaginal delivery is anticipated.
If labor is expected to last longer than the analgesic effects of the spinal drugs chosen or if there is a good possibility of operative delivery, a catheter technique instead of a single injection technique should be considered.
A local anesthetic may be added to a spinal opioid to increase duration and improve quality of analgesia.
Single-injection Spinal Opioids with or without Local Anesthetics
Single-injection spinal opioids with or without local anesthetics may be used to provide effective, although time-limited, analgesia for labor when spontaneous vaginal delivery is anticipated.
If labor is expected to last longer than the analgesic effects of the spinal drugs chosen or if there is a good possibility of operative delivery, a catheter technique instead of a single injection technique should be considered.
A local anesthetic may be added to a spinal opioid to increase duration and improve quality of analgesia.
Pencil-point Spinal Needles
Pencil-point spinal needles should be used instead of cutting-bevel spinal needles to minimize the risk of post– dural puncture headache.
Combined Spinal–Epidural (CSE) Anesthetics
CSE techniques may be used to provide effective and rapid analgesia for labor.
Patient-controlled Epidural Analgesia (PCEA)
PCEA may be used to provide an effective and flexible approach for the maintenance of labor analgesia.
PCEA may be preferable to CIE for providing fewer anesthetic interventions, reduced dosages of local anesthetics, and less motor blockade than fixed-rate continuous epidural infusions.
PCEA may be used with or without a background infusion.
Removal of Retained Placenta
In general, there is no preferred anesthetic technique for removal of retained placenta.
If an epidural catheter is in place and the patient is hemodynamically stable, epidural anesthesia is preferable.
Hemodynamic status should be assessed before administering neuraxial anesthesia.
Aspiration prophylaxis should be considered.
Sedation/analgesia should be titrated carefully due to the potential risks of respiratory depression and pulmonary aspiration during the immediate postpartum period.
In cases involving major maternal hemorrhage, general anesthesia with an endotracheal tube may be preferable to neuraxial anesthesia.
Nitroglycerin may be used as an alternative to terbutaline sulfate or general endotracheal anesthesia with halogenated agents for uterine relaxation during removal of retained placental tissue.
Initiating treatment with incremental doses of intravenous or sublingual (i.e., metered dose spray) nitroglycerin may relax the uterus sufficiently while minimizing potential complications (e.g., hypotension).
Anesthetic Choices for Cesarean Delivery
Equipment, facilities, and support personnel available in the labor and delivery operating suite should be comparable to those available in the main operating suite.
Resources for the treatment of potential complications (e.g., failed intubation, inadequate analgesia, hypotension, respiratory depression, pruritus, vomiting) should be available in the labor and delivery operating suite.
Appropriate equipment and personnel should be available to care for obstetric patients recovering from major neuraxial or general anesthesia.
The decision to use a particular anesthetic technique should be individualized based on anesthetic, obstetric, or fetal risk factors (e.g., elective vs. emergency), the preferences of the patient, and the judgment of the anesthesiologist.
Neuraxial techniques are preferred to general anesthesia for most cesarean deliveries.
An indwelling epidural catheter may provide equivalent onset of anesthesia compared with initiation of spinal anesthesia for urgent cesarean delivery.
If spinal anesthesia is chosen, pencil-point spinal needles should be used instead of cutting-bevel spinal needles.
General anesthesia may be the most appropriate choice in some circumstances (e.g., profound fetal bradycardia, ruptured uterus, severe hemorrhage, severe placental abruption).
Uterine displacement (usually left displacement) should be maintained until delivery regardless of the anesthetic technique used.
Intravenous fluid preloading may be used to reduce the frequency of maternal hypotension after spinal anesthesia for cesarean delivery.
Initiation of spinal anesthesia should not be delayed to administer a fixed volume of intravenous fluid.
Intravenous ephedrine and phenylephrine are both acceptable drugs for treating hypotension during neuraxial anesthesia.
In the absence of maternal bradycardia, phenylephrine may be preferable because of improved fetal acid– base status in uncomplicated pregnancies.
For postoperative analgesia after neuraxial anesthesia for cesarean delivery, neuraxial opioids are preferred over intermittent injections of parenteral opioids.
Postpartum Tubal Ligation
For postpartum tubal ligation, the patient should have no oral intake of solid foods within 6–8 h of the surgery, depending on the type of food ingested (e.g., fat content).
Aspiration prophylaxis should be considered.
Both the timing of the procedure and the decision to use a particular anesthetic technique (i.e., neuraxial vs. general) should be individualized, based on anesthetic risk factors, obstetric risk factors (e.g., blood loss), and patient preferences.
Neuraxial techniques are preferred to general anesthesia for most postpartum tubal ligations.
Be aware that gastric emptying will be delayed in patients who have received opioids during labor and that an epidural catheter placed for labor may be more likely to fail with longer post delivery time intervals.
If a postpartum tubal ligation is to be performed before the patient is discharged from the hospital, the procedure should not be attempted at a time when it might compromise other aspects of patient care on the labor and delivery unit.
Management of Obstetric and Anesthetic Emergencies
Institutions providing obstetric care should have resources available to manage hemorrhagic emergencies.
In an emergency, the use of type-specific or O negative blood is acceptable.
In cases of intractable hemorrhage when banked blood is not available or the patient refuses banked blood, intraoperative cell-salvage should be considered if available.
The decision to perform invasive hemodynamic monitoring should be individualized and based on clinical indications that include the patient’s medical history and cardiovascular risk factors.
Labor and delivery units should have personnel and equipment readily available to manage airway emergencies, to include a pulse oximeter and qualitative carbon dioxide detector, consistent with the ASA Practice Guidelines for Management of the Difficult Airway.
Basic airway management equipment should be immediately available during the provision of neuraxial analgesia.
Portable equipment for difficult airway management should be readily available in the operative area of labor and delivery units.
The anesthesiologist should have a preformulated strategy for intubation of the difficult airway.
When tracheal intubation has failed, ventilation with mask and cricoid pressure, or with a laryngeal mask airway or supraglottic airway device (e.g., Combitube®, Intubating LMA [Fastrach™]) should be considered for maintaining an airway and ventilating the lungs.
If it is not possible to ventilate or awaken the patient, an airway should be created surgically.
Basic and advanced life-support equipment should be immediately available in the operative area of labor and delivery units.
If cardiac arrest occurs during labor and delivery, standard resuscitative measures should be initiated.
Uterine displacement (usually left displacement) should be maintained.
If maternal circulation is not restored within 4 min, cesarean delivery should be performed by the obstetrics team.
Ref : Practice Guidelines for Obstetric Anesthesia: An Updated Report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia. Anesthesiology 2007; 106:843–63.

Post LSCS Analgesia

Post-cesarean section analgesia
Route Drug Pro’s Con’s
NEURAXIAL INTRATHECAL Morphine
Cost-effective
Gold standard Dose-dependent pruritus. Dose-independent PONV. Urinary retention. Oral herpes reactivation. Respiratory depression (usually delayed due to rostral spread).
Diamorphine Quicker onset and increased duration of action compared to IT morphine. Pruritus and vomiting at higher doses.
Fentanyl/Sufentanil Excellent intraoperative analgesia. Lower incidence of PONV and delayed respiratory depression. Little postoperative analgesic benefit.
Meperidine = Pethidine Can be used in patients with contraindication to local anesthetics. Undesirable motor blockade due to local anesthetic properties PONV.
Nalbuphine More favorable side effect profile compared to IT morphine. Less pain control Few evidence in literature.
Clonidine (adjunct) Prolonged postoperative analgesia Postoperative antihyperalgesic properties. Mildly increased intraoperative sedation.
Dexmedetomidine (adjunct) Encouraging results in lower abdominal surgery. No studies in context of cesarean delivery.
Neostigmine (adjunct) Reduces postoperative morphine requirements PONV
Magnesium (adjunct) Reduces postoperative morphine requirements. More studies required.
EPIDURAL Morphine Good postoperative analgesia. Similar side effect profile as IT morphine, but more pruritus.
Diamorphine Good and prolonged postoperative analgesia. Nausea is uncommon. Less pruritus compared to IT diamorphine.
Fentanyl/Sufentanil Appropriate for PCEA
Meperidine = Pethidine Less maternal nausea and similar patient satisfaction compared to IT Morphine. Appropriate for PCEA. Low risk of drug exposure in breastfed infants.
Extended release epidural morphine Prolonged postoperative analgesia. Increased patient mobility and decreased staff workload. High cost-price. Possible interaction with local anesthetics.
Clonidine (adjunct) Prolonged postoperative analgesia. Postoperative antihyperalgesic properties.
Dexmedetomidine (adjunct) Encouraging results in lower abdominal surgery. No studies in context of cesarean delivery
Neostigmine (adjunct) Reduces postoperative morphine requirements. More research required
Magnesium (adjunct) Reduces postoperative morphine requirements. More research required
SYSTEMIC INTRAVENOUS Morphine Appropriate for IVPCA Pruritus, PONV, respiratory depression
Fentanyl Appropriate for IVPCA.
Meperidine = Pethidine Neonatal neurobehavioral depression.
Alfentanil Fast onset of action. Interesting in combination with morphine. High cost-price
INTRAMUSCULAR and SUBCUTANEOUS Ease of administration. Low cost-price. Long history of use in postpartum women. Injection is uncomfortable for patients. Variable blood levels and interval required for absorption. High staff workload. Poorly reported in literature.
ORAL Oxycodone Case reports of neonatal respiratory depression.
Morphine Poorly reported in literature. Pruritus, PONV, respiratory depression.
Tramadol Compatible with breastfeeding. PONV
LOCAL ANESTHETIC TECHNIQUES TARGETING PERIPHERAL NERVE AFFERENTS ILIOINGUINAL AND ILIOHYPOGASTRIC (IIIH) NERVE BLOCK WOUND INFILTRATION TAP BLOCK Good postoperative analgesia. Appropriate for continuous technique. Prolonged postoperative analgesia. Prolonged postoperative analgesia (up to 2 days) Easy to perform. Few complications. Relatively short duration of action. More research to evaluate continuous techniques required. Conflicting results in literature. Relatively high cost of disposable devices. Difficult in obese patients. Risk of peritoneal puncture (solution: ultrasound)
SYSTEMIC ADMINISTRATION OF NON- OPIOID ANALGESICS Paracetamol Little risk associated with paracetamol therapy. Compatible with breastfeeding.
Nonsteroidal antiinflammatory drugs Targets also the visceral component of post-cesarean section pain. Well-documented opioid-sparing effects. Compatible with breastfeeding. Potential problems with bleeding, platelet dysfunction and renal insufficiency. Risk of uterine atony in postpartum period.
COX2-inhibitors Decrease NSAID-related adverse effects (on platelet and gastro-intestinal systems) Poorly reported in literature
Ketamine Anti-hyperalgesic properties Conflicting results in literature. No data on transfer in breast milk.
Gabapentine More research required
Ref:
Post-cesarean section analgesia;
Acta Anaesth. Belg., 2012, 63, 147-167

Medication in the perioperative period

Medication in the perioperative period: stop or continue?
INTRODUCTION
Routinely used medications have many potential interactions with drugs used during surgery, but few situations prohibit concurrent administration. The half-life of routinely used medications and adjustment of the dose according to the perioperative schedule must be considered. Many medications must be continued through the perioperative period, with the last dose taken with a sip of clear liquid up to 2 hours prior to the procedure, and resumed during recovery.
Other drugs must be stopped, replaced, or temporarily administered by another route.
The perioperative period extends from the preoperative day through the operation and into the postoperative recovery.
Overnight fasting reduces the risk for aspiration of stomach contents when the patient is placed under general anesthesia. However, liquids are cleared from the stomach within 2 hours of ingestion, and no differences in the volume or pH of gastric contents is noted in those patients taking clear fluids 2 hours before surgery compared to those taking clear fluids 9 hours before surgery. Therefore, patients can be given their routine medications with sips of water up to 2 hours before anesthesia.
SUMMARY OF RECOMMENDATIONS
I. Cardiovascular System Ischemic heart disease :
Drug Day before Surgery Day of Surgery During Surgery After Procedure
Nitroglycerine Usual dose Usual dose IV infusion if frank ischemia Continue IV dose if needed or until medication can be taken PO
Beta-blockers Usual dose Usual dose plus beta-blocker protocol Usual dose plus beta-blocker protocol Usual dose plus beta-blocker protocol
Calcium channel blockers Usual dose Usual dose morning of surgery Usual dose morning of surgery Continue IV dose until medication can be taken PO
Aspirin Discontinue 1 week before surgery Restart postoperatively at discretion of surgeon
Ticlopidine Discontinue 1 week before surgery Restart postoperatively at discretion of surgeon
II.Hypertension
Drug Day before Surgery Day of Surgery During Surgery After Procedure
Beta-blockers Usual dose Usual dose on morning of surgery with sip of water IV infusion if frank ischemia Continue IV dose if needed or until medication can be taken PO
Calcium channel blockers Usual dose Usual dose on morning of surgery with sip of water IV bolus or infusion (usually not required) Continue IV dose until medication can be taken PO
ACE inhibitors Stop day before Do not take day of surgery IV formulations (usually not required) Continue IV dose until medication can be taken PO
Diuretics Stop day before IV beta-blockers/IV calcium channel blockers Restart when patient on oral liquids
Pottasium Supplements Stop day before;consider checking potassium level Restart when patient on oral liquids
Central-acting sympatholytics Usual dose Usual dose on morning of surgery with sip of water Transdermal clonidine/IV methyldopa Restart when patient on orals liquids
Peripheral sympatholytics Usual dose Usual dose on morning of surgery with sip of water Any IV formulation (usually not required) Restart when patient on orals liquids
Alpha-blockers Usual dose Usual dose on morning of surgery with sip of water Any IV formulation (usually not required) Restart when patient on orals liquids
Vasodilators Usual dose Usual dose on morning of surgery with sip of water IV formulation (usually not required) Continue IV dose until medication can
III. Antithrombotic medication:
Preoperative recommendations concerning antithrombotics and anticoagulants
Acetylsalicylic acid continue / stop 5-7d before surgery
Thienopyridines : Stop unless exception (see text)
clopidogrel (Plavix®) Stop 7 days before surgery
ticlopidin (ticlid®) Stop 10 days before surgery
Prasugrel (efient®) Stop 10 days before surgery
dipyridamole last intake evening before surgery
Vit k Antogonists : continue / stop depending on surgery
Acenocoumarol (Sintrom®) Stop 4 days before surgery
Warfarine (Marevan®) Stop 5-7 days before surgery
fenprocoumarol (Marcoumar®) Stop 7-10 days before surgery
LMWH :
Prophylactic dose Stop 12 hours before surgery
Half or full therapeutic dose Stop 24 hours before surgery
Unfractionated heparin Iv Stop 4-6 hours before surgery / continue
Warfarin
Interruption of warfarin — After stopping warfarin, it usually takes two to three days for the INR to fall to below 2.0, and four to six days for the INR to normalize.
Once the INR is 1.5 or below, surgery can be performed with relative safety in most cases, although a normalized INR is typically required in patients undergoing surgery associated with a high bleeding risk (eg, intracranial, spinal, urologic) or if spinal anesthesia is to be used.
Following surgery and after warfarin is restarted, it takes approximately five days for the INR to rise above 2.0. It is therefore estimated that if warfarin is withheld for five days before surgery and is restarted as soon as possible afterwards, patients would have a subtherapeutic INR for approximately four days before surgery and four days after surgery.
BRIDGING ANTICOAGULATION
Bridging anticoagulation can be defined as the administration of a short-acting anticoagulant, typically a LMW heparin, during the perioperative interruption of warfarin.
In general, such bridging anticoagulation may be considered in patients with the following:
Prior stroke or systemic embolic event
Mechanical mitral valve
Mechanical aortic valve and additional stroke risk factors
Atrial fibrillation and multiple stroke risk factors (eg, CHADS2 ≥4, CHA2DS2-VASc ≥5)
Recent (within three months) venous thromboembolism
Active coronary or peripheral vascular disease
Previous thromboembolism during interruption of warfarin therapy
Major cardiac or vascular surgery
Risk Stratification for Perioperative Arterial and Venous Thromboembolism to Guide Whether Bridging Anticoagulation Is Needed
Thromboembolic Risk Category Clinical Indication for Warfarin Therapy
Atrial Fibrillation Mechanical Heart Valve Venous Thromboembolism
High risk (annual risk >10%)* CHADS2 score 5 or 6 Any mechanical mitral valve Recent (within 3 mo) VTE
Recent (within 3 mo) stroke/TIA Older aortic mechanical valve (caged-ball, tilting disk) High-risk thrombophilia‡
Rheumatic valvular heart disease Recent (within 3 mo) stroke or TIA
Moderate risk (annual risk 5% to 10%) CHADS2 score 3 or 4 Bileaflet aortic valve prosthesis with ≥1 risk factor† VTE within 3–12 mo
Moderate-risk thrombophilia§
Recurrent VTE
Active cancer‖
Low risk (annual risk <5%) CHADS2 score 0–2 (no prior stroke or TIA) Bileaflet aortic bileaflet without any risk factors† VTE >12 mo ago
CHADS2 indicates score based on cardiac failure-hypertension-age-diabetes-stroke; VTE, venous thromboembolism; and TIA, transient ischemic attack.
* Additional patients who may be at high risk include those with prior thromboembolism during interruption of warfarin.
† Age ≥75 years, atrial fibrillation, congestive heart failure, hypertension, diabetes mellitus, or stroke or TIA.
‡ Deficiency of protein C, protein S, or antithrombin; antiphospholipid syndrome; homozygous factor V Leiden or prothrombin gene mutation.
§ Heterozygous factor V Leiden or prothrombin gene mutation
‖ Cancer that is metastatic or treated within the past 6 months.
After warfarin is stopped, 5 to 6 days before surgery (to allow sufficient time for its anticoagulant effect to wane), bridging anticoagulation is started 3 days before surgery, with the last dose given 24 hours before surgery. After surgery, bridging is resumed no earlier than 24 hours after surgery; at the same time, warfarin is restarted. Bridging is continued, typically for 4 to 6 days, until the anticoagulant effect of warfarin has resumed and the blood is sufficiently thinned again.
Enoxaparin (Lovenox) 1 mg/kg twice daily is often used.
Recommendations for anticoagulant substitution therapy:
Thromboembolic risk Substitution
High risk in mitral valve surgery, multiple valve surgery, old mechanical valves, atrial fibrillation with a CHADS2 score 5-6, thromboembolic incident less than 3 months ago Therapeutic dose of LMWHs until 24 hours before surgery. Start LMWH if INR less than 2. Continue LMWH postoperatively until 2 daysof therapeutic INR. Restart VKA (usual dose) the day after surgery if hemostasis is sufficient
Moderate risk in bileaflet aortic valve surgery with other risk factors, atrial fibrillation with a CHADS2 score 3-4, thromboembolic event 3-12 months ago. HALF-THERAPEUTIC DOSE of LMWHs until 24 hours before surgery.
Low risk in atrial fibrillation with a CHADS2-VASC score equal or less than 2, thromboembolic event more than 1 year ago. PROFYLACTIC DOSE of LMWHs until 12 hours before surgery.
IV. Perioperative Medication Management for Patients With Diabetes and Hypothyroidism:
Drug Day before Surgery Day of Surgery During Surgery After Procedure
Oral hypoglycemics Usual dose Omit dose Insulin (SC or IV) Insulin until patient is no longer NPO
Insulin Usual dose Omit dose Insulin (SC or IV) Usual dose
Thyroxine Usual dose Usual dose on morning of surgery with sip of water Restart the dose when patient is no longer NPO
V. Perioperative Medication Management in Patients With Epilepsy
Drug Day before Surgery Day of Surgery During Surgery After Procedure Substitute Drug if Needed
NSAIDs with long half-life Discontinue 1 week before surgery IM preparation until patient is on oral liquids
NSAIDs with short half-life Discontinue 2-3 days before surgery IM preparation until patient is on oral liquids
NSAIDs in patients with arthritis Low-dose steroids
VI. Perioperative Management of NSAIDs
Drug Day before Surgery Day of Surgery During Surgery After Procedure Substitute Drug if Needed
NSAIDs with long half-life Discontinue 1 week before surgery IM preparation until patient is on oral liquids
NSAIDs with short half-life Discontinue 2-3 days before surgery IM preparation until patient is on oral liquids
NSAIDs in patients with arthritis Low-dose steroids
VII. Perioperative management of psychotropic agents:
Name or class of drug Clinical considerations Recommended strategy for surgery with brief NPO state Recommended strategy for surgery with prolonged NPO state
Tricyclic antidepressants Continuation may increase the potential for arrythmias. Abrupt withdrawal can lead to insomnia, nausea, headache, increased salivation and increased sweating. Continue therapy up to and including day of surgery for patients on high doses. Patients on low doses and in whom perioperative arrythmia is likely should discontinue for 7 days prior to surgery. Resume with oral intake. No parenteral substitution available.
Serotonin reuptake inhibitors Increased risk of bleeding. Discontinue therapy 3 weeks prior to surgery in patients undergoing high risk procedures (such as certain CNS procedures). Resume with oral intake. No parenteral substitution available.
Monoamine oxidase inhibitors If continued, and direct acting sympathomimetic agents like ephedrine are used during anesthesia, can result in severe HTN. If agents like meperidine or dextromethorphan are used can result in “serotonin syndrome”. For emergency procedures a MAO safe anesthetic technique should be used. For other surgeries, anesthesiologist and psychiatrist should collaborate and decide either to use MAO-safe anesthetic technique or discontinue the medication. If discontinued should be stopped for 2 weeks prior to surgery. Resume with oral intake. No parenteral substitution available.
Lithium Continuation may prolong the effect of muscle relaxants and due to impaired renal concentrating ability can cause hypovolemia and hypernatremia. Continue therapy up to and including day of surgery with close monitoring of electrolytes and volume status. Resume with oral intake. No parenteral substitution available.
Valproic acid No known adverse effects. Continue therapy up to and including day of surgery. Continue therapy up to and including day of surgery. Resume with oral intake. A parenteral Formulation (valproate sodium) is available.
VIII. Perioperative management of endocrine agents:
Name or class of drug Clinical considerations Recommended strategy for surgery with brief NPO state Recommended strategy for surgery with prolonged NPO state
Oral contraceptives Continuation may increase risk of venous thromboembolism. Stopping can result in unwanted pregnancies. Continue up to and including the day of surgery for procedures with low to moderate risk of venous thromboembolism. Stop 4-6 weeks before surgery for procedures with high risk for thromboembolism. Instruct on alternate forms of contraception and obtain serum pregnancy test immediately before surgery. Continue up to and including the day of surgery for procedures with low to moderate risk of venous thromboembolism. Stop 4-6 weeks before surgery for procedures with high risk for thromboembolism. Instruct on alternate forms of contraception and obtain serum pregnancy test immediately before surgery.
Hormone replacement therapy Continuation may increase risk of venous thromboembolism. Continue up to and including the day of surgery for procedures with low to moderate risk of venous thromboembolism. Stop 4-6 weeks before surgery for procedures with high risk for thromboembolism. Continue up to and including the day of surgery for procedures with low to moderate risk of venous thromboembolism. Stop 4-6 weeks before surgery for procedures with high risk for thromboembolism. Resume when tolerating oral medications.
Selective estrogen receptor modulators Continuation may increase risk of venous thromboembolism. Continue for surgeries with low risk of venous thromboembolism, and discontinue for surgeries with moderate to high risk for venous thromboembolism. When stopped should be stopped at least 4-6 weeks prior to surgery. When SERMs are used for breast cancer treatment consult oncologist. Continue up to and including the day of surgery for procedures with low risk of venous thromboembolism. Stop 4-6 weeks before surgery for procedures with moderate to high risk for thromboembolism. Resume when tolerating oral medications. When SERMs are used for breast cancer treatment consult oncologist.
IX. Perioperative management of gastrointestinal and pulmonary agents:
Name or class of drug Clinical considerations Recommended strategy for surgery with brief NPO state Recommended strategy for surgery with prolonged NPO state
H2 blockers No known adverse effects Continue therapy up to and including day of surgery. Continue therapy up to and including day of surgery. Substitute IV forms available for prolonged postoperative NPO state.
Proton pump inhibitors No known adverse effects. Continue therapy up to and including day of surgery. Continue therapy up to and including day of surgery. Substitute IV H2 blockers for prolonged postoperative NPO state.
Inhaled bronchodilators (beta agonists And anticholinergics) No known adverse effects. Continue therapy up to and including day of surgery. Continue therapy up to and including day of surgery. Use nebulized forms if patient unable to comply with inhalation maneuver.
Theophylline No known adverse effects but very narrow range between therapeutic and toxic level. Continue up to day before surgery. Discontinue the evening before surgery Continue up to day before surgery. Discontinue the evening before surgery. Resume with PO intake. Use nebulized or inhaled beta agonist or anticholinergics.
Leukotriene inhibitors No known adverse effects. Continue therapy up to and including day of surgery. Continue therapy up to and including day of surgery and resume when patient able to take oral medications.
Potential perioperative effects of common herbals
Ginseng Hypoglycemia
Inhibits platelet aggregation (may be irreversible)
Inhibits PT/PTT in animals
Increases anticoagulation effect of warfarin
Ephedra Myocardial infarction, cerebrovascular accident
Depletes endogenous catecholamine stores, which can cause intraoperative hemodynamic instability
Life-threatening interaction with MAO inhibitors
Garlic Inhibits platelet aggregation (may be irreversible)
Increases fi brinolysis
Increases risk of bleeding
Equivocal blood pressure lowering
Ginkgo Inhibits platelet-activating factor, leading to biloba increased bleeding risk
Kava Sedation, anxiolysis
Increases sedative effect of anesthetics
Potential for addiction, tolerance, withdrawal
St. John’s wort Many drug–drug interactions via induction of CYP 450 enzymes
Echinacea Activates cell-mediated immunity
Allergic reactions
Immunosuppression
Valerian Increases sedative effect of anesthesia
Withdrawal
May increase anesthesia requirements.
Ref :
1. Perioperative Medication Management: Author: Nafisa K Kuwajerwala, MD; Chief Editor: William A Schwer, MD. Medscape.
2. Medication in the perioperative period : stop or continue ? A review. Acta Anaesth. Belg., 2011, 62, 193-201.
3. National Guidelines. Steps to reduce Surgical Risk – Guidelines for Perioperative evaluation. NGC-8596.
4. Perioperative medication management. Authors: Visala Muluk, MD., David S Macpherson, MD, MPH.
5. Perioperative medication management: General principles and practical applications. Cleveland Clinic Journal of Medicine – volume 76 • supplement 4 November 2009
Posted in ANAESTHESIA PEARLS 2014

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