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Unformatted text preview: Epidurals, Spinals, and More More April 2009 Dr. Eismon Table of Contents Table Anatomy Anatomy Techniques Side Effects Concerns of anticoagulation I think that Turkey is performing think Gobblfication Anatomy Anatomy Epidural Epidural Local anesthetics injected into the epidural space spread in cranial and Local caudal directions from the level at which they are administered. The drug bathes the nerve roots as they pass through the anterolateral The epidural space, but roots above and below the limit of spread of local anesthetic remain unaffected. anesthetic This gives an epidural local anesthetic block a top and a bottom level of This effect, with the site of injection somewhere in between. There may be preferential spread of local anesthetic to one side of the There spinal canal, and when this occurs the level and intensity of blockade on each side of the body can be different. each Occasionally single nerve roots are missed altogether resulting in a patchy Occasionally block. Local anesthetic solutions injected into the epidural space are influenced Local by gravity. With the patient in a sitting position the lower segments tend to be blocked, and when supine the block spreads higher. In the lateral position, the dependent side tends to block preferentially Friendly advice to pregnant anesthesia residents anesthesia Positioning Positioning Procedure Procedure A new twist for the Sitting position new In the mid-calf position, the patient In rests the lower legs (mid-calf), rather than the knees, on the edge of the bed, sitting somewhat further back on the bed than in the conventional sitting position. As a result, the knees are slightly flexed with the patient’s back nearer to the practitioner. The patient’s neck is flexed forward and the arms are crossed in front of the body (Fig. 1). crossed One advantage of the mid-calf One position is that the patient naturally assumes an ideal position for placement of a neuraxial block with little instruction. The shoulders fall forward and the flexed position achieved appears to optimally open the spaces between the spinous processes processes British Journal of Anaesthesia 2006 97(4):583-584; British doi:10.1093/bja/ael231 Technical Difficulty Technical The fatness- most The problematic: get a harpoon and a lucky charm charm Old people suck- calcified Old ligaments and arthur is in town: you may have to abandon procedure abandon Prior back surgery- Heavy Prior Metal Metal Autoimmune + collagen Autoimmune d/o - have ligaments like paper don’t slip or you might get a spinal tap might Technical Difficulty Technical Kyphoscoliosis: this gentleman Kyphoscoliosis: looks virtually impossible to place neuraxial anesthesia but clinicians used Taylors approach for spinal anesthesia anesthesia In the sitting position, the right In posterior superior iliac spine (PSIS) was identified. A point 1cm below and medial to the PSIS was marked, Using a Quincke type spinal needle, the site was entered in cephalomedial direction. Dural puncture was successful at the second attempt. second In patients where a midline In approach at the lumbar level is difficult, the lumbosacral approach is an excellent alternative for providing spinal anesthesia to perineal and lower extremity surgery surgery M.G.M. Medical College M.G.M. Indore Madhya Pradesh India Indore Tattoos Tattoos A Medline and EMBASE search of Medline the English literature using the key words: spinal, epidural, tattoos, tattooing, complications did not find any reports or concerns regarding neuraxial anesthesia through tattooed areas. However, one might postulate that there could be long-term implications from depositing a pigmented tissue core in the epidural or subarachnoid space. Based on the limited information Based available it is possible that inserting an epidural or spinal needle through a tattoo could cause longthrough term problems such as term arachnoiditis or a neuropathy secondary to an inflammatory reaction, but we don’t know. reaction, Canadian Journal of Anesthesia 49:1057-1060 (2002) 49:1057-1060 Epidural catheter placed detected by flouroscopy flouroscopy Spinal Spinal Physiological effect of spinal blockade at different levels Differences Differences CSE Z CSE CSE Failure CSE Caudal Caudal Block of the sacral and lumbar Block nerve roots. It is useful as a supplement to general anesthesia and for provision of postoperative analgesia. This technique is popular in pediatric patients. Catheter insertion may be performed for continuous caudal block. continuous The S5 processes are remnants The and form the cornua, which provide the main landmarks for indentifying the sacral hiatus. The hiatus is covered by the sacro-coccygeal membrane. The canal contains areolar The connective tissue, fat, sacral nerves, lymphatics, the filum terminale and a rich venous plexus. Caudal Injection for Pain patients Caudal Caudal epidural anesthesia in children can be used in children Lower abdominal surgery: (incision below the umbilicusT10 sensory level) Lower (incision especially perineal, genitourinary or ilioinginual surgery. Lower extremity surgery (hip, leg and foot): though at times it is difficult to Lower though achieve a satisfactory block to the distal 1/3 of the foot. Newborn and premature infants: If used as the sole anesthetic, caudal Newborn If epidural anesthesia reduces the risk of respiratory depression from residual neuromuscular blockade (pancuronium) and inhalation anesthetics. Postneuromuscular operative apnea associated with general anesthesia, is reduced with caudal operative anesthesia but not abolished. Neuromuscular disease such as muscular dystrophy. There is a high Neuromuscular There incidence of postoperative respiratory failure due to a combination of general anesthesia and muscle weakness. Caudal epidural anesthesia indicated for lower extremity surgery (very common in these patients). Malignant hyperthermia: it is generally accepted that all local anesthetic Malignant it agents are considered safe agents Caudal Doses Caudal Pediatric population 0.5 ml/kg, 0.25% bupivacaine 0.5 (sacro-lumbar block) (sacro-lumbar 1 ml/kg, 0.25% bupivacaine ml/kg, (upper abdominal block) (upper 1.2 ml/kg,0.25% bupivacaine 1.2 (mid-thoracic block) (mid-thoracic (Doses described by Armitage). Adults: 20-30 ml 0.25-0.5% Adults: bupivacaine. Average volume of the sacral canal is 30-35 ml. the Epidural fat in children has a Epidural loose and wide-meshed texture, whereas in adults it becomes more densely packed and fibrous. Hence, local anesthetic spread is greater in children. spread Caudal Placement Position Caudal The sacral hiatus in an The infant or young child is easily identified because the landmarks are more superficial. The sacral hiatus is formed by failure of fusion of the fifth sacral vertebral arch. The remnants of the arch are known as the sacral cornu, and are located on either side of the hiatus. Caudal Block Technique Caudal The needle is inserted at a 60-degree angle and the needle is advanced until a "pop" is felt. The needle is then lowered to a 20-degree angle and advanced an additional 2-3 mm to make sure the bevel is in the caudal epidural space The pop felt is the needle The piercing the sacrococcygeal membrane There should be very little There resistance to injection. The dura ends at S2, but may The extend further. Aspirate to confirm the absence of blood/cerebrospinal fluid and inject local anesthetic while feeling for inadvertent subcutaneous injection with the other hand other In children, the block typically In performed after general anesthesia has been induced and before surgery has commenced commenced Caudal Caudal Neuraxial Contraindications Neuraxial Effects of Neuraxial anesthesia Effects Complications and side effects of neuraxial methods neuraxial Blood Patch Blood The epidural blood patch The consists of injecting 5-20 mLs of autologous blood into the epidural space, in the region of the suspected dural 'hole.' Autologous blood is typically Autologous drawn in a sterile fashion, and then injected as a bolus into the epidural space. In 90% of cases, the response is In positive and immediate. Subsequently, long-term relief of PDPH occurs in the majority of cases PATIENTS ON HEPARIN THERAPY There should be at least a 1-h delay between neuraxial needle placement There and heparin administration. The epidural catheter should be removed 2–4 h after the last heparin dose The and 1 h before subsequent heparin administration. Partial thromboplastin time (PTT) or activated coagulation time (ACT) Partial should be monitored to avoid excessive heparin effect. Dilute concentrations of local anesthetics are recommended to minimize Dilute motor blockade; the patient should be followed postoperatively for early detection of reoccurrence of motor blockade. In the event of a traumatic (bloody) or difficult needle placement, there are In no data to support mandatory cancellation of surgery. PATIENTS RECEIVING LMWH AND NEURAXIAL ANESTHESIA Monitoring of anti-Xa level is not recommended. The administration other anticoagulant medications with LMWHs may increase the The risk of spinal hematoma. risk The presence of blood during needle placement and catheter placement does not The necessitate postponement of surgery. However, the initiation of LMWH therapy should be delayed for 24 h postoperatively. should The first dose of LMWH prophylaxis should be given no earlier than 24 h The postoperatively and only in the presence of adequate hemostasis. postoperatively In patients who are on LMWH, needle/catheter placement should be performed at In least 12 h after the last prophylactic dose of enoxaparin or 24 h after higher doses of enoxaparin (1 mg/kg every 12 h), 24 h after dalteparin (120 U/kg every 12 h or 200 U/kg every 12 h), and 24 h after tinzaparin (175 U/kg daily). 200 There should be a 12-h interval between the last prophylactic dose of enoxaparin There and removal of the epidural catheter. For higher doses of enoxaparin, a 24-h delay is recommended. is The LMWH may be administered Summary of Guidelines on Anticoagulants and Neuraxial Blocks I. Antiplatelet medications Aspirin, NSAIDs, COX-2 inhibitors May continue Pain clinic patients: Aspirin preferably stopped 2–3 days in thoracic and cervical blocks Epidurals (author’s preference—see text) Epidurals Thienopyridine derivatives a. Clopidogrel (Plavix)—discontinue for 7 days b. Ticlopidine (Ticlid)—discontinue for 14 days Do not perform a neuraxial block in patients on more than one antiplatelet b. drug. GPIIB/IIIA inhibitors: Time to normal platelet aggregation a. Abciximab (Reopro) = 24–48 h b. Eptifibatide (Integrilin) = 4–8 h c. Tirofiban (Aggrastat) = 4–8 h Antiplatelet medications (ASA, Plavix) are usually given after GPIIb/IIIa inhibitors. The above guidelines on aspirin and Antiplatelet Plavix should be adhered to. II. WarfarinCheck INR INR ≤ 1.5 before neuraxial block or epidural catheter removalIII. Heparin Subcutaneous heparin (5000 units SQ q 12 h) Subcutaneous heparin is not a contraindication against a neuraxial block Neuraxial block should preferably be performed before SQ heparin is given Risk of decreased platelet count with SG heparin therapy > 5 days Risk Intravenous heparin Neuraxial block: 2–4 h after the last intravenous heparin dose Wait ≥ 1 h after neuraxial block before giving intravenous heparin Wait IV. Low-molecular-weight heparin (LMWH) No concomitant antiplatelet medication, heparin, or dextran LMWH Preop a. Wait 12 h before a neuraxial block: b. Enoxaparin (Lovenox) 0.5 mg/kg bid (prophylactic dose) c. Wait 24 h before a neuraxial block: d. Enoxaparin (Lovenox), 1 mg/kg bid (therapeutic dose) e. Enoxaparin (Lovenox), 1.5 mg/kg qd f. Dalteparin (Fragmin), 120 units/kg bid g. Dalteparin (Fragmin), 200 units/kg qd h. Tinzaparin (Innohep), 175 units/kg qd h. LMWH Postop: a. LMWH should not be started until after 24 h after surgery b. LMWH should not be given until ≥ 2 h after epidural catheter removal b. Patients with epidural catheter who are given LMWH The catheter should be removed at the earliest opportunity. Enoxaparin (0.5 mg/kg): Remove the epidural catheter ≥ 12 h after last dose. ...
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This note was uploaded on 12/16/2011 for the course BIOLOGY 101 taught by Professor Mr.wallace during the Fall '11 term at Montgomery College.

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