NEUROAXIAL BLOCK

NEUROAXIAL BLOCKIMAM SUDRAJAT, dr, SpAn, Msi MedSpinal, Epidural, and Caudal Anesthesia

General considerationsPreoperative assessment is similar to that for general anesthesia. The area where the block should be examined for potential difficulties or pathology. A history of abnormal bleeding and a review of the patient's medications may indicate a need for additional coagulation studies.Patients should be given a detailed explanation of the planned procedure, with risks and benefits. As with general anesthesia, patients should receive appropriate monitoring and have an IV line in place. Oxygen, equipment for intubation and positive-pressure ventilation, and drugs to provide hemodynamic support should be available.

Contraindications to neuraxial anesthesia

AbsolutePatient refusal.Localized infection at skin puncture site.Generalized sepsis (e.g., septicemia, bacteremia).CoagulopathyIncreased intracranial pressure.RelativeLocalized infection peripheral to regional technique site.Hypovolemia.Central nervous system disease.Chronic back pain.

Spinal anesthesiaSpinal anesthesia involves administering local anesthetic into the subarachnoid space.

AnatomyThe spinal canal extends from the foramen magnum to the sacral hiatus. Three interlaminar ligaments bind the vertebral processes together:Superficially, the supraspinous ligament connects the apices of the spinous processes.The interspinous ligament connects the spinous processes on their horizontal surface.The ligamentum flavum connects the caudal edge of the vertebrae above to the cephalad edge of the lamina below. The spinal cord extends the length of the vertebral canal during fetal life, ends at about L-3 at birth, and moves progressively cephalad to reach the adult position near L-1 by 2 years of age. The conus medullaris, lumbar, sacral, and coccygeal nerve roots branch out distally to form the cauda equina. Spinal needles are placed in this area of the canal (below L-2), because the mobility of the nerves reduces the danger of trauma from the needle.CSF is a clear colorless fluid that fills the subarachnoid space.

Table 16.1. Suggested minimum cutaneous levels for spinal anesthesia

Operative Site LevelLower extremitiesT-12HipT-10Vagina, uterusT-10Bladder, prostateT-10Lower extremities with tourniquet T-8Testis, ovariesT-8Lower intraabdominalT-6Other intraabdominalT-4

Spinal column curvatures that influence the spread of anesthetic solutions.The Advantages of Spinal Anaesthesia

Cost. Anaesthetic drugs and gases are costly and the latter often difficult to transport. Patient satisfaction. If a spinal anaesthetic and the ensuing surgery are performed skilfully, the majority of patients are very happy with the technique and appreciate the rapid recovery and absence of side effects.Respiratory disease. Spinal anaesthesia produces few adverse effects on the respiratory system as long as unduly high blocks are avoided.Patent airway. As control of the airway is not compromised, there is a reduced risk of airway obstruction or the aspiration of gastric contents. Diabetic patients. There is little risk of unrecognised hypoglycaemia in an awake patient. Muscle relaxation. Spinal anaesthesia provides excellent muscle relaxation for lower abdominal and lower limb surgery.Bleeding. Blood loss during operation is less than when the same operation is done under general anaesthesia. Visceral tone. The bowel is contracted during spinal anaesthesia and sphincters are relaxed although peristalsis continues. Normal gut function rapidly returns following surgery.Coagulation. Post-operative deep vein thromboses and pulmonary emboli are less common following spinal anaesthesia.

Epidural anesthesiaEpidural anesthesia is achieved by introducing local anesthetics into the epidural space.

Anatomy. The epidural space extends from the base of the skull to the sacrococcygeal membrane. Posteriorly, it is bounded by the ligamentum flavum, the anterior surfaces of the laminae, and the articular processes. Anteriorly, it is bounded by the posterior longitudinal ligament covering the vertebral bodies and

Subarachnoid and epidural spaces.

13Pemeriksaan keadaan anestesi

Diagram dermatom pin prick alkohol 14Obat dan alat

15 Posisi : lateral kiri

Desinfektan : betadin alkohol

16 Infiltrasi lidokain 2 %

Tusuk L 3 - 4 atau L 4 5 , dengan jarum epidural no.18

17Sasaran jarum

18 Masukkan 2 3 ml obat anestesi lokal

19Masukkan kateter epidural

20Aspirasi, hasil (-) cabut jarum

21 Fiksasi kateter

22Masukkan lagi 3 ml obat anestesi lokal, observasi 5 menitDosis fraksional 3-5 ml Interval waktu 5 menit alternatif lain : infus kontinyu

Caudal anesthesia

Caudal anesthesia is obtained by placing local anesthetic into the epidural space in the sacral region.Anatomy. The caudal space is an extension of the epidural space. The sacral hiatus is formed by the failure of the laminae of S-5 to fuse. The hiatus is bounded laterally by the sacral cornua, which are the inferior articulating processes of S-5. The sacrococcygeal membrane is a thin layer of fibrous tissue that covers the sacral hiatus.