CAUDAL BLOCK and caudal anaesthesia in children

caudal

1. PRESENTER:DR.ABDUL RASHEED. 1 ST YEAR POSTGRADUATE, NRIIMS. MODERATOR:DR.B.E.V.GIRISH. ASSISTANT PROFESSOR,NRIIMS. CAUDAL BLOCK 2/28/2024 1

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3. CONTENTS: CAUDAL ANAESTHESIA: ANATOMY OF SACRUM SACRAL CANAL CONTENTS PHYSIOLOGY OF CAUDAL BLOCK SYSTEMIC EFFECTS TECHNIQUES INDICATIONS CONTAINDICATIOINS COMPLICATIONS A SPECIAL MENTION ON HIGH SPINAL TOTAL SPINAL 2/28/2024 3

4. INTRODUCTION: Caudal Anesthesia: Is one of the most commonly used regional techniques in pediatric patients. Can be also be used in adults. 2/28/2024 4

5. HISTORY: Caudal anesthesia was first described at the turn of last century by two French physicians,Fernand Cathelin and Jean- Anthanase Sicard. The technique predated the lumbar approach to epidural block by several years. 2/28/2024 5

6. ANATOMY OF SACRUM: The typical sacrum is a triangular shaped bone dorsally convex formed by gradual fusion of the lamina of the 5 sacral vertebral segments, which is completed by the 20th year of life. The bone articulates cephalad with the 5th lumbar vertebra and caudad with coccyx. The concave anterior surface is smooth and in part supports many important structures such as the iliac vessels, rectum and fetal head. The posterior surface is rough, because of fusion of spinous processes. 2/28/2024 6

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8. The 5th sacral vertebra is unfused. There are four foramina, the fifth being absent. Failure of fusion of the lamina of the 5th vertebral segment results in a hiatus, that communicates with epidural space. The sacral hiatus is a v shaped or U-shaped notch formed by sacral cornua . Hiatus is covered by sacrococcygeal ligament. The first foramen is 0.5cm from midline and 2.5cm above the level of the posterosuperior iliac spine, while the fifth foramina is expected to be 1cm from the midline. The third foramina is commonly the largest. Distance between the apex of hiatus and the dural space is 47 mm. 2/28/2024 8

9. ANOMALIES: Deficient lateral wall Trauma deformity Extended hiatus. 2/28/2024 9

10. CONTENT OF SACRAL CANAL: Terminal part of dural sac, ending at S2, on a line joining the posterosuperior iliac spines. The 5 sacral nerve roots and the coccygeal nerves. The sacral epidural venous plexus. Filum terminale . Loose areolar fat Lymphatics. 2/28/2024 10

11. PHYSIOLOGY OF CAUDAL BLOCK: Anesthesia occurs slowly Anaesthesia usually is first noted on the buttocks about the sacral hiatus. Pain is the first modality of sensation to be lost, followed by touch and temperature. Pain is usually lost two segments higher than touch loss. Motor Fibers are affected last 2/28/2024 11

12. SYSTEMIC EFFECTS: CVS Changes: Hypotension Bradycardia Respiratory system: Respiration is not affected to that extend by caudal anaesthesia. Endocrine system: No changes in ACTH, immunoreactive beta-endorphins, ADH, cortisol, catecholamines , insulin and GH levels. 2/28/2024 12

13. EQUIPMENT: The following equipment is required to perform a caudal epidural block. Appropriately sized syringe Needle or IV access catheter Medication Skin cleaning solution, commonly alcohol, chlorhexidine, or an iodine solution Personal protective equipment (sterile gloves, mask, head covering) 2/28/2024 13

14. Ultrasound can assist in caudal epidural placement in pediatric or adult patients. A study by Shin et al. demonstrated that identification of the sacral hiatus by ultrasound facilitated the completion of the caudal epidural placement.[6] The gold standard for a successful caudal epidural block is fluoroscopy-guided. However, this is rarely performed in an operating room environment due to impracticality and radiation exposure to both the patient and providers. 2/28/2024 14

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16. TECHNIQUE: Blind Caudal Epidural Block: The sacral hiatus is identified by the landmarks of the sacral cornua found on each side superior to the gluteal cleft and at the apex of a triangle formed by the posterior superior iliac crests. The beveled needle or angiocatheter is inserted at a 45-degree angle after skin preparation. A "pop" or "give" may be felt, indicating progression through the sacrococcygeal ligament and entrance into the epidural space. This loss of resistance technique correlates with a 26% miss rate.[8] Thus, many suggest performing the “whoosh test,” which has a much higher specificity; this uses auscultation of the thoracolumbar region while injecting air into the caudal epidural space. [7] 2/28/2024 16

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22. Ultrasound-Guided Caudal Epidural Block: With the patient in prone or lateral decubitus position, a 7 to 13 MHz linear transducer (2 to 5 MHz curved transducer if the patient is obese) can be placed transversely placed in the middle of the sacrum. The transverse view shows the following hyperechoic structures: the superficial sacrococcygeal ligament in between two sacral cornua , and the deeper sacral bone. The hypoechoic structure between the sacrococcygeal ligament and the sacral bone is the target. The probe is then turned 90 degrees for the longitudinal view so that the needle can be inserted “in-plane” into the sacral hiatus. To avoid a dural puncture, the needle should not be advanced beyond 5mm after the tip of the apex since the needle is not visible after the tip of the apex. Unidirectional flow on color doppler can help identify the success of a caudal block. 2/28/2024 22

23. Fluoroscopy-Guided Caudal Epidural Block: With the patient in the prone position, the sacral hiatus is visualized as an abrupt drop-off at the end of the S4 lamina. The needle can advance into the sacral canal, and by injecting a contrast medium, needle tip placement can be confirmed, and intravascular or intrathecal injection can be ruled out. 2/28/2024 23

24. Resistance is felt after a few millimeter as the needle engages in the ligament followed by sudden loss of resistance as it penetrates which is felt as a ʻPOPʼ as it enters the sacral extradural space (1st position). “Whoosh test” can be used to predict successful needle placement. This involve listening with a stethoscope over the midline lumbar spine for a characteristic whoosh sound on injection of 2-3ml of air through caudal needle. 2/28/2024 24

25. ANAESTHETIC SOLUTION: Bupivacaine 0.125 to 0.25% Levobupivacaine 0.125–0.25% Ropivacaine 0.1–0.375%, 2/28/2024 25

26. ADDITIVES: Clonidine is the most common adjunctive drug for single-injection caudal blocks. Various mechanisms have been proposed to account for its favourable effect. Chief among them is presumably that clonidine binds to alpha-2 receptors in the dorsal horn of the spinal cord.50, 51 Dosages of 1–2 μg / kg are recommended as effective. [4] Dexmedetomidine has a shorter half-life time than clonidine. Dosage 1–2 μg / kg as effective. According to an up-to-date review, caudal anaesthesia will last longer with dexmedetomidine than with morphine as adjuvant while remaining on a par with clonidine in quality. Haemodynamic effects, notably bradycardia, were uncommon and mostly related to the higher (2 μg /kg) dose concentration. 2/28/2024 26

27. Opioids have a long tradition as adjuvant drugs in caudal anaesthesia.Current guidelines recommend 10–30 μg /kg for morphine, but advise against fentanyl or sufentanil . These two, being lipophilic opioids, provide up to 4 h of effective anaesthesia , whereas morphine as a water-soluble drug is effective for up to 24 h. Caudal epidural morphine has side-effects of reduced gastrointestinal mobility and postoperative nausea/vomiting. Pruritus is another well-known and common problem, but the true risk is respiratory depression, sometimes with a delayed onset. Thus, morphine use should be confined to strictly selected patients. Ketamine binds to spinal opioid and N-methyl-D-aspartate receptors and has no respiratory side-effects. In a preservative-free form, both racemic ketamine and esketamine can be safely administered at 0.5–1 mg /kg into the epidural space. 2/28/2024 27

28. In patients with chronic low back pain and radiculopathy, corticosteroids can be injected into the caudal epidural space. Corticosteroids such as dexamethasone, betamethasone, methylprednisolone, and triamcinolone are the agents of choice. 2/28/2024 28

29. DOSE RECOMMENDED: ARMITAGE FORMULA: For low caudal block include T11 = 30 ml. For moderate caudal block include T7 = 45 ml For high caudal block include T4 = 60 ml. 2/28/2024 29

30. INDICATIONS: Surgery of anus and rectum Gynecological perineal procedure Obstetric delivery Management of vasospastic disease of lower extremity Management of pelvic & extremity pain. Circumcision Herniorrhaphy orchidopexy 2/28/2024 30

31. CONTRAINDICATIONS: Active disease of CNS, except idiopathic epilepsy. Inter vertebral disc Infection at the site of block Pilonidal sinus or cyst. Abnormalities of Sacrum. Obesity 2/28/2024 31

32. COMPLICATIONS: Subdural, intravascular, or intraosseous injection. Infection. Hypotension. Injury to the nerve roots Antesacral Injection with perforation of the rectum. Hematoma formation. Local anesthetic toxicity. Delayed respiratory depression. Urinary retention. Sacral osteomyelitis. [5] 2/28/2024 32

33. A devastating complication of a caudal block is total spinal anesthesia that can occur from an inadvertent dural puncture with subsequent intrathecal injection of local anesthetic.This issue is much more common in infants due to the caudad displacement of the dural sac that ends at the S3-4 level (as compared to S1-2 in adults). Also, caudal epidural blocks have a higher incidence of local anesthetic-related seizures than brachial plexus or lumbar or thoracic epidural blocks. 2/28/2024 33

34. SPIEGEL FORMULA: Spiegel Formula: V = 4 + D-15/2; V=Volume of drug; D=Distance in cm from C7 to hiatus. 2/28/2024 34

35. TOTAL SPINAL ANAESTHESIA: 1. Total central neurological blockade. 2. This is one of the major hazards to be encountered in performing epidural anaesthesia . It can also occur during interscalene block of Brachial plexus. Incidence for the epidural 1 in 1000 cases. It is the result of unrecognized spinal puncture and the infection of large volume of anaesthetic solution during epidural anaesthesia . It usually comes on soon after injection. It may be delayed for 30-45 mins . 2/28/2024 35

36. SIGNS AND SYMPTOMS: Profound bradycardia - because of total sympathectomy and relative increase in vagal tone. 2. Profound hypotension • Vasodilation of capacitance vessels. • Decrease venous return to heart and • Decrease systemic vascular resistance Apnea for considerable time blockade of C3 – C5. Phrenic nerve block (Diaphragmatic paralysis). 4. Dilated pupils due to sympathetic blockade. 5. Loss of consciousness 6. Motor blockade – muscle paralysis. 2/28/2024 36

37. MANAGEMENT: Turn the patient into supine position. Trendelenburgʼs position elevate legs. Ventilate with 100% O2. It is important to ventilate the patient by mask before proceeding to ETT intubation. If ventilation with 100% O2 by mask is very difficult (or) impossible rapid intubation. No muscle relaxant (or) hypnotic agent necessary. Intravenous fluid bolus. 2/28/2024 37

38. • Vagolytic dose of atropine 2 – 3 mg. • Ephedrine 10 – 25 mg. • Epinephrine 10 – 100 mcg.→ If hypotension (or) bradycardia not resolved. • Surgical procedure • Continued • Airway is secured • Hemodynamic response managed and patients is stable. • Postponed: If there is doubt about hemodynamic (or) CNS status of patients. 2/28/2024 38

39. Can be avoided by: Careful technical application. Aspiration for spinal fluid. Test dose Incremental doses 2/28/2024 39

40. HIGH SPINAL: Prevents compensatory vasoconstriction Blocks sympathetic cardiac accelerator fibers that arise at T1 - T4. 2/28/2024 40

41. EFFECTS: Profound Hypotension may result from: • Vasodilation • Bradycardia • Decrease contractility 2/28/2024 41

42. MANAGEMENT: Preloading 10 - 20 ml/kg of IV fluids Excessive bradycardia should be treated with Atropine Hypotension with Vasopressor Direct α adrenergic agonist ( phenylephrine); Increases venous tone, arteriolar constriction Direct β adrenergic effects (Ephedrine); increases Heart rate & contractility, indirect effect - vasoconstriction. Epinephrine 2/28/2024 42

43. REFERENCES: MILLER’S ANAESTHESIA, NINTH EDITION. MORGAN & MIKHAIL’S CLINICAL ANAESTHESIOLOGY, SEVENTH EDITION. BARASH CLINICAL ANESTHESIA, EIGHTH EDITION. Wiegele M, Marhofer P, Lönnqvist PA. Caudal epidural blocks in paediatric patients: a review and practical considerations. Br J Anaesth . 2019 Apr;122(4):509-517. doi : 10.1016/j.bja.2018.11.030. Epub 2019 Feb 1. PMID: 30857607; PMCID: PMC6435837. Sanghvi C, Dua A. Caudal Anesthesia . [Updated 2023 Mar 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551693/# Shin S, Kim JY, Kim WO, Kim SH, Kil HK. Ultrasound visibility of spinal structures and local anesthetic spread in children undergoing caudal block. Ultrasound Med Biol. 2014 Nov;40(11):2630-6. 2/28/2024 43

44. 7. Eastwood D, Williams C, Buchan I. Caudal epidurals: the whoosh test. Anaesthesia . 1998 Mar;53(3):305-7. 8 .Barham G, Hilton A. Caudal epidurals: the accuracy of blind needle placement and the value of a confirmatory epidurogram . Eur Spine J. 2010 Sep;19(9):1479-83. 2/28/2024 44