Epidural Anaesthesia

Epidural Anesthesia – Technique

Epidural anesthesia, also known as EDA, back anesthesia or epidural, is a form of regional anesthesia with injection of local anesthesia into the epidural space, through a slightly thicker needle, usually 9 cm long. The anesthesia is used for lower body anesthesia as well as certain pain indications, such as labour pain. The anesthesia is usually positioned with “Loss-of-Resistance” technique and the introduction of a catheter into the epidural space. The anesthesia is started with bolus and full dose through the catheter, followed by continuous infusion. For anesthesia, local anesthetics are used alone or in combination with opioids and/or adrenaline.

Indications

  • Regional anesthesia for lower body surgery, for example peripheral vascular surgery, abdominal surgery or orthopedic surgery.
  • For combined anesthesia during surgical procedures on lower body under general anesthesia.
  • Postoperative pain relief after surgery, such as abdominal surgery.
  • Obstetric analgesia
  • Pain relief in the lower body half, e.g. ischemic pain.

Technique of Epidural Insertion

Body position

The patient is positioned before the blockade in sitting or lying. Obese patients or pregnant women preferably in the sitting position. The puncture and placement of epidural occurs under sterile conditions. In urological surgery and sectio it is usually much easier to perform epidural with the patient in sitting than in the resting position. In orthopedic surgery, epidural is usually laid with the patient lying on the side. The skin of the back is washed and sterilized. In the lying side position it is very important with maximum flexion in the lumbar part and the patient far out on the edge of the table, usually an assistant will assist and adjust the situation by hand.

  • Bildresultat för Spinal Anesthesia
  • Bildresultat för epidural needle
  • Bildresultat för epidural catheters
  • Bildresultat för epidural catheters
  • Bildresultat för spinal anesthesia
  • Bildresultat för spinal anesthesia

Loss of Resistance (LOR)

Usually, Loss of Resistance (LOR) technique is used with puncture using a low-resistance (5-10 ml) low-pressure syringe. The syringe may also be air-filled (5: 1 ml). Alternatives to LOR technology are the technique of “hanging drop” in the epidural needle without mandrels. The hanging drop is sucked in when the epidura is penetrated. This technique is best suited to the patient in sitting.

Median technique

70-90 degree angle of the needle to the skin plane and 20-40 degree angle in the cranial direction. Always support hand wrist (buckles) or knees against patient back during puncture. Two fingers hold the wings of the epidural needle during insertion. Loss of resistance usually occurs at 4 cm distance (3-6 cm) from the skin surface when the needle is inserted with great care.

Lateral technique

1-2 cm from the median line between the spinal sprains slightly upwards by 70-90 degrees to the skin plane and 30-50 degrees in the cranial direction.

Patient sitting or lying. In childbirth episodes, it is usually much easier to position the patient in sitting than lying. The catheter should be relatively easy to enter the epidural space, significant resistance suggests incorrect position

Contraindications

  • Disseminated Intravascular Coagulation
  • Any significant coagulation disturbance
  • Patient is opposed to epidural anesthesia
  • Skin infection on the injection site
  • Earlier EDA or spinal complication.
  • Neurological abnormal symptoms of peripheral genesis
  • Some anticoagulation therapies

Relative contraindications

  • Neurological disorders
  • Spinal cord, spinal stenosis or fresh trauma in the back
  • Sepsis
  • Patients with unconsciousness

Coagulation tests

  • APT(T) should be normal
  • PK/INR > 1.4 and TPC > 100, if comfort gain
  • PK/INR > 1.6 or TPC 50-100, if morbidity gain
  • PK/INR > 1.8, TPC 30-50, doubtful with EDA, may be placed if mortality gain. Spinal anesthesia produces less risk of puncture than EDA.
  • At PK/INR > 1.4 or TPC < 100, adjust the coagulation first.

Level of puncture

  • Thoracotomi Th 6-7
  • High laparotomy Th 8-9, Th 10-11
  • Large laparotomy Th 10-11
  • Low laparotomy Th10-L1, L1-L2, L2-L3
  • Nefrectomy Th 8-10
  • Hip, knee surgery L1-L2

Landmarks

  • Spina Scapulae – Th 3
  • Angulus scapulae – Th 7
  • Iliac crest  – L4

Sensory blockade – propagation

  • Th 1 – Angulus sterni
  • Th 4 – Mamill
  • Th 8 – Rib cage
  • Th 10 – Umbilical level
  • Th 12 – Groin

The Bromage Scale determines the degree of motor block

derm2large.gif

  • 0 = Can lift the leg with stretched knees
  • 1 = Can bend in knee joint
  • 2 = Can bend in ankle
  • 3 = Can not bend in the ankle, paralysis

Monitoring

  • VAS Scale
  • Blood pressure and pulse control, leg mobility every 4 hours
  • Sedation rate and respiratory rate 1 times/hour first 6 h (fentanyl, sufenta) and 12 h (morphine) at startup. At dose change/bolus 2 and 4 h respectively
  • Then check every four hours.

If the filter has loosened

Use sterile gloves, wash the catheter with 70% alcohol, air dry, cut 5 cm of the catheter with sterile scissors, fill new filter with LA, connect new adapter and new filter to the catheter and fix well, eg with Tegaderm and “button”.

Removal of epidural catheter

  • The patient do not usually need any sedation.
  • Wash the location of insertion with alcohol.
  • Remove the catheter cautiously
  • Check the catheter tip after removal
  • Keep urinary catheter for 6 hours
  • Keep intravenous access for 6 hours
  • Continue monitoring for 4 hours
  • Wait at least 2 hours before new anticoagulation therapy

EDA and anticoagulation

  • LMWH > 5000E/40 mg – at least 24 hours prior to EDA insertion
  • LMWH 2500 – 5000 units – should be given no later than 10 h before insertion/manipulation
  • From EDA insertion/manipulation to LMWH is given – after at least 2 hours
  • Heparin i v – wait 3 h + new APT
  • Single therapy low dose ASA and or NSAIDs – insertion at comfort gain
  • High dosage of ASA – insertion in case of morbidity gain
  • ASA/Plavix – insertion in case of mortality gain
  • Plavix should be discontinued for 5 days/High dose ASA 7 days/Low dose ASA 3 days

Medicines in epidural block

Bolus dose

  • Ropivacaine (Naropin) 2 mg/ml 4-6 ml at thoracic level, 6-12 ml at lumbar level
  • Mepivacaine (Carbocain) 2 mg/ml, 4-6 ml at thoracic level and 6-12 ml lumbar level, respectively
  • Fentanyl 20-50 μg, Sufentanil 10-20 μg, Morphine Special 2-3 mg

Maintenance dosage with EDA

  • Breivik’s mixture (Marcain 1.0 mg/ml + Fentanyl 2 μg/ml + Adrenaline 2 μg/ml) bolus 2-6 ml, continuous infusion 6-14 ml/h.
  • Ropivacaine (Naropin) 2 mg/ml, bolus 2-6 ml, continuous infusion 4-6 ml/h at thoracic level, 6-12 ml/h at lumbar level
  • Mepivacaine (Carbocain) 2 mg/ml, bolus 2-6 ml, continuous infusion 4-6 ml/h at thoracic level and 6-12 ml/h at lumbar level
  • Bildresultat för Spinal Anesthesia

Epidural Anaesthesia – Drugs and dosages

Test dose at the start of an epidural

Test dose of local anesthetic is given to exclude spinal or intravasal catheterization. As a test dose, 2-4 ml of bupivacaine (Marcain) 5 mg/ml, Ropivacaine (Naropin) 2 mg/ml or Mepivacaine (Carbocain) 20 mg/ml are given. Observe the patient after the test dose and check heart rate and blood pressure for at least 5 minutes. If the patient is awake find out that he can move his legs and arms unhindered. Also check with cold if the test dose gives a feeling of impairment. Adrenaline as an additive in the test dose may indicate at heart rate increase that the catheter is located intravasally.

Epidural Anesthesia for Surgical Procedures

Local Anaesthetic AgentConcentrationBolus dose (ml)Bolus dose (mg)LA for continuous infusionBolus dose (mg)
Mepivacaine (Carbocaine®) 10 mg/ml10-20 ml100-200 mg
Mepivacaine (Carbocaine®) 20 mg/ml10-17.5 ml 200-350 mg
Bupivacaine (Marcaine®) 2.5 mg/ml 20 ml 50 mg followed by 6-16 ml/h15-40 mg *
Bupivacaine (Marcaine®) 5 mg/ml 15-30 ml75-150 mg
Bupivacaine (Marcaine®) 5 mg/ml20 ml followed by 50 mg followed by 2.5 mg/ml, 6-16 ml/h15-40 mg *
Levobupivacaine (Chirocaine®) 5.0-7.5 mg/ml10-20 ml 50-150 mg
Ropivacaine (Naropin®) 5-7.5 mg/ml 15-20 ml100-200 mg
Ropivacaine (Naropin®) 5 mg/ml 6-10 ml 6-10 ml/h30-50 mg *
* Every 4-6 hours alternatively in continuous infusion depending on the desired number of anethetized segments and the age of the patient

Epidural for Obstetric Analgesia

Local Anaesthetic AgentConcentrationOpioidBolus doseContinuous infusion
Bupivacaine (Marcaine®) 2,5 mg/ml6-10 ml (15-25 mg)2-5 ml/h (5-12,5 mg/h)
Bupivacaine (Marcaine®)1 mg/ml plusSufentanil 1 microg/ml8-12 ml6-9 ml/h
Levobupivacaine (Chirocaine®) 2,5 mg/ml6-10 ml (15-25 mg)4-10 ml/h (5-12,5 mg/h) (1,25 mg/ml)
Ropivacaine (Naropin®) 2 mg/ml10-15 ml (20-30 mg),2-5 ml/hr (4-10 mg/hr)(2 mg/ml )
Ropivacaine (Naropin®) 1 mg/ml plusSufentanil 1 microg/ml12 ml6-9 ml/h
Standard mixture of local anesthetics plus opioid is usually given at a dose of 4-16 ml/h

Conversion of Epidural from Obstetric Analgesia into Caesarian Sectio ("Top-Up for C-Sec")

Local Anaesthetic AgentConcentrationVolume (ml)Dose (mg)Opioid
Ropivacaine (Naropin®)5 mg/ml15-20 ml 113-150 mg+ Sufentanil 25 μg
Levobupivacaine (Chirocaine®) *5 mg/ml15–20 ml 75–100 mg
Bupivacaine (Marcaine®)5 mg/ml15–20 ml75–100 mg
Chloroprocaine (Nesacaine®)30 mg/ml (3% )15–20 ml
* Slow injection

Epidural Block in Caesarian Sectio

Local Anaesthesia AgentConcentrationLoading VolumeLoading Dose
Levobupivacaine (Chirocaine®) 5 mg/ml*15–30 ml 75–150 mg
Mepivacaine (Carbocaine®)20 mg/ml 10–17,5 ml 200–350 mg
Bupivacaine (Marcaine®)5 mg/ml15–30 ml 75–150 mg
Chloroprocaine (Nesacaine®)30 mg/ml (3% )15–20 ml in bolus
Ropivacaine (Naropin®)5 mg/ml15-20 ml 113-150 mg
* By slow injection

Morphine epidurally can be given intermittently or continuously. Common practice is 3 times a day.

Normal dose: Morphine 4 mg x 3.

Continuous morphine can be given in the concentration of 0.03-0.05 mg/ml. Sufentanil is given in the concentration of 0.25-1 μg/ml.


Epidural Anesthesia for Postoperative Pain

Continuous Epidural Analgesia for Postoperative Pain Relief

Continuous epidural anesthesia for postoperative pain reliefStandard mixture of local anesthetics plus opioid is usually given at a dose of 4-16 ml /hour
Local anestheticOpioidAdrenaline additionDosage
Bupivacaine 1,0 mg/mlFentanyl 2 μg/ml +Adrenaline 2 μg/ml8-14 ml/hour (Breivik's blend/BFA)
Bupivacaine 2,5 mg/mlSufentanil 0,5 μg/ml8-12 ml/hour
Bupivacaine 2,5 mg/mlMorphine Special 0,4 mg/ml5-10 ml/hour
Bupivacaine 1,0 mg/mlSufentanil 1 μg/ml8-16 ml/hour
Ropivacaine 2 mg/mlSufentanil 1 μg/ml8-16 ml/hour
Ropivacaine 2 mg/mlMorphine Special 0,4 mg/ml5-10 ml/hour
Levobupivacaine 1,25 mg/mlSufentanil 1 μg/ml8-16 ml/hour
Levobupivacaine 1,25 mg/mlMorphine Special 0,4 mg/ml 5-10 ml/hour
Continuous epidural anesthesia without opioids:
Bupivacaine 2,5 mg/ml5-7,5 ml/hour
Ropivacaine 2 mg/ml6-14 ml/hour
Levobupivacaine 1,25 mg/ml10-15 ml/hour
Levobupivacaine 2.5 mg/ml5-7,5 ml/hour

Epidural opioids

Registered drugs for epidural use in Sweden are Morphine Special (morphine) and Sufentanil (Sufenta). Even fentanyl (Fentanyl) is used epidurally. The drugs are given continuously in infusion or intermittent in bolus, 3-4 times/day. Morphine can be given three times a day or in continuous infusion.

  • Morphine 3-4 mg x 3 in EDA. Initially, up to 5 mg of morphine hydrochloride may be given if necessary. If necessary, a dose of 2-4 mg of morphine hydrochloride may be given when the effect of the first dose declined, usually after 6-24 hours.
  • Fentanyl 2 μg/ml, 4-12 ml/h should be given in continuous infusion with or without local anesthetic agents.
  • Sufentanil 1 μg/ml, 8-16 ml/h should be given in continuous infusion with or without local anesthetic agents. Sufentanil can also be given in bolus without local anesthetic 25 μg epidurally x 3-4.

EDA controls

  • Heart rate and blood pressure every 4 hours
  • Pain intensity (VAS) every 4 hours
  • Motor control of the arms and legs (en. Bromage) every 4 hours
  • Injection site 3 times/day
  • Respiratory rate every 4 hours at opioid supplement
  • Sedation rate was 4 hours at opioid supplement.

The above controls can be performed every 6 hours after a day without dose increase. Extra check 10 min and 30 min after increased infusion rate or epidural bolus dose. Extra controls 30 min and 60 min after reactivation of EDA. Extra controls 2 times/hour for 2 hours when sedative or respiratory depression medication. Dosage and bolus doses are given only after contact with a pain nurse or anesthetist. Aggregate should be changed after 3 days.

EDA och anticoagulants

At least 10 hours between given LMWH (Klexane® or Fragmin®) and EDA insertion or catheter adjustment. EDA is withdrawn > 2 hours before or > 10 hours after given LMWH. Control of motoring (Bromage) after 6, 8 and 12 hours after the extracted epidural catheter. Documented! CAD should remain 6 hours after withdrawal of epidural catheter.

EDA complications

Epidural hematoma is a rare but serious complication that requires immediate treatment. Symptoms: Pain in the back and sometimes in the legs as well as increasing paralysis in the legs. Epidural abscess is another serious complication that requires immediate treatment. Symptoms: Fever, general discomfort, back pain and increasing paralysis of the legs. In case of suspicion of the above complications, the infusion in the EDA should be discontinued and anesthetist will be contacted immediately!

Controls of patients with EDA

Controls of motor skills, sedation,
nausea and itching
Score0 p1 p2 p3 p
Motor skills according to BromageFull mobility in hip, knee and footCan touch the knee and hip joint, but do not raise the legCan touch the ankleCannot touch the knee or ankle
Motor skills in the armsNormal motor skills in armsWeakness in arms
Sedation DegreeAbsolutely awakeDrowsy, light sedationSedated but possible to awakeDeep sedation, not possible to awakeS: Sleeping a natural sleep
NauseaNot nauseousNon treated nauseaTreating nauseaVomiting
ItchingNo itchingUntreated itchingTreated itching

Assessment of motor block according to Bromagederm2large.gif

0: Full mobility in hip, knee and foot

1: Can touch the knee and hip joint, but do not raise the leg

2: Can touch the ankle

3: Cannot touch the knee or ankle

 

Mobility in arms

0: Normal mobility in arms

1: Weakness in arms

Degree of Sedation

0: Absolutely awake

1: Drowsy, easy sedated

2: Sedated but araousable

3: Deep cedar, not araousable

S: Sleeping a natural sleep

Nausea

0: Not nauseous

1: Not treated nausea

2: Treated nausea

3: Vomiting

Itching

0: No itching

1: Untreated itching

2: Treated itching


Patient Controlled Epidural Anaesthesia

Patient controlled epidural anesthesia (PCEA) contains epidural continuous infusion plus patient controlled bolus doses or intermittent infusion with bolus doses only, with the ability for the patient to self-control the treatment at his own request in the form of small bolus doses. PCEA is given epidural and the aim is to provide better pain relief with smaller doses in total compared with continuous continuous infusion. The method allows the patient to control the treatment for own activities with mobilization and the need for pain relief. The method smooths out the large inter-individual differences between patients in the need for postoperative pain relief. Typically, PCEA is used for 2-4 days after medium and large surgical procedures and in childbirth analgesia. PCEA is well suited for childbirth analgesia and has been shown to provide better pain relief compared with conventional EDA. In childbirth analgesia, PCEA can be given either as self-administered bolus doses or as continuous infusion plus PCEA. When setting bolus doses only, these are given in larger doses than in combination with continuous continuous infusion with PCEA, for example 5 ml instead of 2 ml per dose.

Risk groups are elderly patients, heavily overweight, patients with respiratory insufficiency, severely injured or unhealthy patients. In childbirth EDA, risk groups are predominantly overweight and patients with preeclampsia.

Common pumps used are GEM star, CADD or Deltec.

Standardinfusion PCEA

Continuous infusion of 4-10 ml/h. Bolusdos 2 ml, shutter time 10 minutes and maximum dose of bolus doses per hour adjusted to 4. At max 10 ml / t infusion with max. Pressure 4, a total dose of 18 ml/h is given, which is calculated as the maximum dose.

Some suggestions for combination therapy with PCEA

  • Bupivacaine (Marcain®) 1.0 mg/ml + Fentanyl 2 μg/ml + Adrenaline 2 μg/ml. Dosage: 4-10 ml/h, bolus dose 2 ml.
  • Ropivacaine (Narop®) 2 mg/ml, + Sufentanil 1 μg/ml, 3-10 ml/h, bolus 2 ml during surgery. The next morning you can switch to Ropivacaine (Narop) 1 mg/ml + Sufenta 0.5 μg/ml to allow patient patient mobilization according to the operator’s instructions. This infusion may continue for a further few days.
  • Ropivacaine (Narop®) 2 mg/ml + Sufentanil 1 μg/ml + Clonidine 3 μg/ml. 3-10 ml/h, bolus 2 ml.

In postoperative/ICU obstetrics treatment, the number of doses requested, the number of doses delivered and the total dose given are recorded and documented. The goal of PCEA is VAS <4 and 1-2 bolus doses per hour. In the care department, it is important to supervise and check every four hours of VAS, respiratory rate, sedation rate, nausea, itching, blister function. Additional controls must be made if the doses are increased with controls every 30 minutes for two hours. In case of insufficient pain relief, dosage doses can be given every 10 minutes until good pain relief is achieved. If the number of PCEA doses exceeds 3 per hour, the continuous infusion is increased. In case of insufficient pain relief at the maximum dose, consider adjuvant pain treatment or to change the epidural. In the treatment of patients with mild preeklampsi, coagulation tests should be checked no later than 6 hours prior to the establishment of an EDA. In case of severe eclampsia, these samples (PK/INR/APT(T)/TPC) should not be older than 2 hours.


Dr Knudsen’s Test for CSF

Knudsens test is a simple bedside study that can detect the presence of cerebrospinal fluid (CSF). This test can be used in suspicion of spinal puncture of an epidural catheter or at basic scull fracture with cerebrospinal fluid leakage. You take a cotton pad or a paper pad and imprint it with colored chlorhexidine solution. Then you take the liquid you want to investigate on the cotton pad. If you get a color switch to red, you have CSF in the test and a positive Knudsen’s test. The final picture below shows the results of a saliva study from a patient with a basic scull fracture and CSF leakage. Comparative paper pad is loaded with normal saliva.