Goals. Epidural anaesthesia. Mechanical ventilation. Cardiopulmonary rescucitation

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2 Goals Epidural anaesthesia Mechanical ventilation Cardiopulmonary rescucitation

3 Why administer an epidural analgesic? Gold standard pain relief for hind limb surgery, single injection lasts for hours Low adverse reaction risk Cheap Simple technique to learn Animal welfare The patient s wellbeing, great PR with your clients and your staff Lowers patient mortality and morbidity No client objection to cost of analgesia

4 contraindications hypovolaemia fixed cardiac output sepsis/local skin infection coagulation disorders

5 ligamentum flavum spinal cord cauda equina CSF epidural space

6 Location of the lumbosacral space Most dorsally prominent points of the wings of the ilium

7 L7 S1

8 Lumbosacral space

9 epidural analgesia you will need: morphine (10 mg per ml, preservative free) bupivicaine 0.5% 22g spinal needles (1.5 & 3 inches) 2, 5 or 10 ml glass syringe (or plastic loss of resistance syringe) sterile paper drape syringes, gloves etc

10 sterile, single use, plastic loss of resistance syringe

11 epidural analgesia dose rates 0.5% bupivicaine 0.2 ml/kg morphine (10 mg/ml) 0.1 mg/kg The drugs are mixed in the one syringe prior to injection.

12 Open all of the sterile items

13 morphine 10mg/ml

14 morphine 10mg/ml

15 bupivicaine 0.5%

16 Add the morphine to the bupivicaine and mix

17 epidural analgesia position» ventral or» lateral iv fluids» ml/kg bolus

18 Prepare as for aseptic surgery» iodine scrub» chlorhexidine/ alcohol» iodine solution epidural analgesia

19 epidural analgesia palpate dorsal prominence of wings of the ilium palpate lumbosacral space

20 epidural analgesia 22 g spinal needle insert at the lumbosacral space advance until just through ligamentum flavum

21 epidural analgesia remove stylet observe for CSF

22 epidural analgesia remove stylet observe for CSF If CSF, discard 2/3 of solution and top up morphine to 0.1 mg/kg

23 Injection of local anaesthetic into the CSF is often termed spinal anaesthesia. Compared to epidural anaesthesia, a smaller volume is used to avoid excessive cranial spread of the solution. Onset of analgesia is more rapid with spinal anaesthesia than with epidural anaesthesia. If CSF appears in the hub of the needle or can be aspirated then the loss of resistance test is not needed

24 epidural analgesia remove stylet observe for CSF observe for blood if blood is seen, withdraw needle, clean & try again

25 epidural analgesia loss of resistance test glass syringe or plastic Loss of resistance syringe tight fit on needle air or saline

26 Loss of resistance Disposable syringe

27 epidural analgesia inject drugs over seconds onset of action: bupivicaine 20 min lignocaine 10 min morphine 40 min

28 epidural analgesia The epidural local anaesthetic results in a blockade of the somatic nervous system and sympathetic nervous system Total peripheral resistance falls about 30% Administer IV fluids bolus prior to surgery 10-20ml/kg replacement fluids over 10 minutes

29 epidural analgesia Position in dorsal or lateral recumbency for 5-10 minutes to bathe sensory (dorsal) spinal nerve roots. :

30 epidural analgesia Position in dorsal or lateral recumbency for 5-10 minutes to bathe sensory (dorsal) spinal nerve roots. : With lateral recumbency, the patient should be positioned so that the the surgical site is dependent.

31 epidural analgesia Next... reduce concentration of volatile anaesthetic maintain light level of general anaesthesia monitor arterial pressure

32 epidural analgesia during recovery from anaesthesia: give NSAID empty bladder re-warm duration of analgesia: epidural morphine = hours epidural bupivicaine = 4-6 hours

33 epidural analgesia during recovery from anaesthesia: With» give bupivicaine, NSAID the sensory block lasts longer than the motor block.» empty Very occasionally, bladder some block will persist for more than» re-warm 12 hours after the injection. duration of analgesia: epidural morphine = hours epidural bupivicaine = 4-6 hours

34 potential problems neurological damage vanishingly rare infection extremely rare (1 in 5,000) provided aseptic technique hypotension common, but easily managed with IV fluid load Hypotension with local anaesthetics (TPR 30%) Segmental sympathetic blockade T12 greater splanchnic nerve Cardio-acceleratory sympathetic nerves RHS T1-4 Supraspinal effects especially hydrophilic morphine absorption into CSF systemic absorption

35 potential problems Constipation occasional urinary retention common, easily managed by expressing or catheterising bladder after surgery pruritis unusual inadvertent subarachnoid (spinal) injection especially cats and young dogs inadvertent IV injection causing cardiac arrest rare, treat CPR + IV 20% Intralipid 1.5ml/kg

36 Artificial ventilation

37 Artificial ventilation For full presentation on artificial ventilation please go to and select the tab labelled For Veterinarians

38 Artificial ventilation A practical guide

39 adverse effects of IPPV circulation reduction of blood flow to right atrium increase in pulmonary input impedance reduced capacitance of pulmonary bed

40 adverse effects of IPPV Try not to exceed a maximum inspiratory pressure of 20cm H 2 O Unless the airway pressure is measured with a manometer, you don t know!

41 adverse effects of IPPV circulatory effects minimised by: increase in tone of capacitance vessels minimise depression of the sympathetic nervous system adequate circulating volume minimise mean airway pressure Inspiratory to expiratory time ratio I:E ratio < 1:2 abolition of thoracic& abdominal m. tone maximise inspiratory flow rate fast & slow alveoli

42 adverse effects of IPPV barotrauma High inspiratory pressures can lead to pneumothorax or pneumomediastinum closed chest: damage with inflation pressures > 70 cm H 2 O open chest: damage with inflation pressures > 40 cm H 2 O

43 adverse effects of IPPV Barotrauma or volutrauma? Hyperinflation (volutrauma) injures the diseased lung Overdistension is more insidious and ultimately more injurious than barotrauma Hyperinflation leads to gross oedema, increased lung weight and cellular damage

44 adverse effects of IPPV Barotrauma or volutrauma? Total lung volume is reduced in pulmonary disease associated with trauma or sepsis Ventilation with a normal tidal volume may approach total lung capacity Damage is diffuse & heterogenous in the diseased lung.(slow and fast alveoli)

45 adverse effects of IPPV Volutrauma and the diseased lung Extensive research on ARDS and animal models of acute lung injury Lung injured animals subject to high airway pressures & normal tidal volumes gross pathology changes similar to paired control high tidal volumes led to gross oedema, increased lung weight & cellular damage Damage due to overdistension is synergistic with toxininduced pulmonary endothelial injury

46 adverse effects of IPPV In Summary: There is a considerable differences in the ventilatory requirements of a patient with healthy lungs compared to that with lung damage or disease. Provision of artificial ventilatory must match individual patient needs in order to optimise outcomes.

47 Measure peak inspiratory pressure circle absorber Bain

48 Choices of ventilator 1. Direct patient ventilator 2. Anaesthetic machine ventilator 3. Using a direct patient ventilator to run as an anaesthetic machine ventilator o Bag in the bottle (2 separate circuits) o Connect ventilator by a long 22mm corrugated tubing to the connection site of the rebreathing bag in the anaesthetic machine s patient breathing circuit (circle, Bain or T piece)

49 Direct patient ventilator

50 Anaesthetic machine ventilator

51 Using direct patient ventilator as an anaesthetic machine ventilator

52 Artificial ventilation: Monitor!

53 Cardiopulmonary rescucitation

54 Latest on CPR Journal of Veterinary Emergency and Critical Care 22(2) 2012, pp Updates in the American Heart Association guidelines for cardiopulmonary resuscitation and potential applications to veterinary patients Barbara L. Maton, DVM and Sean D. Smarick, VMD

55 Latest on CPR: technique Be selective. Acute arrest: Yes Chronic underlying disease: result of many slowly developing derangement until cumulative effect is catastrophic: No ABCDEF for pets CABDEF for people Airway, breathing, circulation drugs, electrical defibrillation, follow up

56 Latest on CPR: technique Dog < 15kg cardiac pump 3 rd -6 th rib lower third chest beats/min Dog > 15kg thoracic pump 7 th -8 th rib at widest chest 100 beats/min

57 Latest on CPR: ABC or CAB ABC in pets as most arrests are PEA, asystole and associated with respiratory disease and hypoxia Right lateral recumbency, preferably head down Continuous chest compressions /min. Do not stop (at most 10 sec interruptions) IPPV but don t stop chest compressions Between breaths allow lungs to fully deflate (to FRC) Dog < 15kg cardiac pump 3 rd -6 th rib lower third chest Dog > 15kg thoracic pump 7 th -8 th rib at widest chest Internal cardiac massage after 2-5min esp. big dogs

58 Latest on CPR: Defibrillation o Electrical defibrillation o External o 2 5 Joules/kg (up to 10) monophasic. o Biphasic defibrillators 30% (higher survival) o Internal Joules kg -1 o Lowest energy setting, then step dose up after each unsuccessfully shock o Cardiac massage inter discharge for 2 minutes

59 Latest on CPR: drugs Adrenalin 0.1mg/kg (0.1ml/kg 1:1000) iv Then maintenance 0.1ug/kg/min (1ml 1:1000 to 1L Hartmann s soln, infuse at 1ml/10kg/min) Vasopressin Vasoconstrictor 0.8 u/kg iv. Can repeat once Asystole, VF, VT & PEA (pulseless electrical activity), EMD Electromechanical dissociation, Non-perfusing rhythm Superior to adrenalin for VT in animals

60 Latest on CPR: drugs Anti-arrythmics Lidnocaine 1-4mg/kg. VT or relapsing VF after CPR Amiodarone 5mg/kg IV over 10 mins. Shock resistant VT & VF, AF, narrow complex SVT. Do not use: Ca, glucose, atropine, HCO3

61 Latest on CPR: drugs Administration of drugs IV, followed by saline chaser, elevate arm sec IV is best IO (Intra-osseous administration) is good, IT (intra-tracheal) is last resort. Double dose except adrenalin 10x dose and dilute in 5-10ml sterile water. IC (intra-cardiac) not recommended

62 Latest on CPR: drugs IV Fluids Only shock doses if pre-arrest hypovolemia Euvolemia: Crystalloids D 20ml/kg bolus C 10ml/kg bolus Hetastarch D 5ml/kg bolus C 2.5ml/kg bolus 7.5% saline D 2-4ml/kg Hypothermia oC is OK post-arrest Success =Team work. Requires leaning and practice

63 Practise

64 CPR Protocol latest recommendations For free copies

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