Perioperative Anesthetic & Pain Management in Small Animal Practice

Transcription

1 Perioperative Anesthetic & Pain Management in Small Animal Practice

2 Objective: To introduce anesthetic and pain management options in: Elective surgery Trauma Major surgery

3 Objectives Of This Lecture Present a wide range of surgical procedures. Provide some options for management Stimulate discussion on these and other options Encourage final protocols should be based on evaluation of each patient

4 History: Canine Lumps & Bumps 2 year old, castrated male canine, mixed breed 15 kg body weight Presented with: 3 small lumps easily palpable through the skin on the neck & back region Procedure: Surgical removal

5 Option 1: Canine Lumps & Bumps Dexmedetomidine 20 µg/kg IM,15-20 minutes before surgical procedure Addition of local nerve block with lidocaine subcutaneous at the lesion Option 2: 5 µg /kg IM dexmedetomidine Followed in 15 minutes with 2.2 to 3.3 mg/kg IV propofol for general anesthesia

6 Minor Fight Wound Repair - Feline History: 2 year old, castrated male feline, mixed breed Aggressive patient requiring cleanup of recent wounds Procedure: Potential suture and antibacterial therapy

7 Minor Fight Wound Repair - Feline Option 1: 0.25 mg /kg diazepam IM or IV + 5 mg /kg IM ketamine for perioperative management & postoperative analgesia Option 2: 20 µg /kg IM dexmedetomidine* + 5 mg/kg IM ketamine for the same purpose (*alpha 2 agonist, dexmedetomidine, provides a longer period of sedation & analgesia than diazepam)

8 Minor Fight Wound Repair - Feline Option 3: 0.05 mg/kg IM acepromazine mg/kg IM butorphanol as a preanesthetic Followed in 15 minutes with sufficient calming of the aggression with 4 to 6 mg/kg IV propofol to induce anesthesia

9 Elective Surgery- Canine OHE History: 1year old, intact female canine, mixed breed 10 kg body weight Normal vital signs Procedure: OHE

10 Elective Surgery- Canine OHE Option 1: Premedication with acepromazine 0.05 mg/kg IM & butorphanol 0.2 mg/kg IM Subsequent induction of anesthesia 15 minutes later with sodium thiopental to effect (reduced dosage due to the analgesic benefits of the premedication) After induction with thiopental, anesthesia is maintained with required levels of isoflurane delivered in oxygen

11 Elective Surgery- Canine OHE Additional Postoperative Pain Management: Opioid agonist Continue with repeat doses of butorphanol at 0.2 mg/kg by injection NSAIDs

12 Elective Surgery- Canine OHE Option 2: Glycopyrrolate 0.01 mg/kg IM 10 minutes prior to other medications Dexmedetomidine 2 to 5 µg/kg IV or IM as a preanesthetic Followed by propofol at 2.2 to 3.3 mg/kg IV for induction Maintenance with either halothane, isoflurane or sevoflurane during the operative procedure

13 Elective Surgery- Canine OHE Additional Postoperative Analgesia: NSAIDs Opioid agonist 5 to 10 µg/kg of dexmedetomidine

14 Elective Surgery- Feline Castration History: 3 year old, domestic shorthair, 3 kg body weight Excellent condition Preanesthetic: 0.25 mg/kg diazepam or 20 µg/kg dexmedetomidine IM Followed with 5 mg/kg of ketamine IM for induction After preparation of the surgical site: A small bleb of lidocaine without epinephrine injected SQ over the scrotum, at the two incision sites and in the cremaster muscle (for additional analgesia both during and post-surgery)

15 Ophthalmology- Cataract Removal History: 14 year old Stabilized diabetic (vs. non diabetic)

16 Ophthalmology- Cataract Removal Option 1: Preanesthetic administration of butorphanol at 0.2 mg/kg followed by Propofol induction at 4.4 mg/kg IV Immediately intubate and maintain with isoflurane Option 2: Longer lasting analgesics may be considered in non-diabetics

17 Ophthalmology- Cataract Removal Postoperative Analgesia: Additional butorphanol NSAID: such as carprofen at 2.2 mg/kg BID

18 Ophthalmology- Cataract Removal Considerations: Due to the diabetes, alpha 2 agonists have not been suggested in this case since, they reduce insulin secretion and contribute to hyperglycemia Suggest reversible opioid agonist Caution: morphine may cause vomition and increased ocular pressure

19 Orthopedics Canine Long Bone Fracture History: 2 year old, St. Bernard 60 kg body weight Long bone fracture of the forelimbs Good health at time of accident Upon presentation: Serious ventricular arrhythmias, trauma to the thoracic wall & associated respiratory abnormalities

20 Orthopedics Canine Long Bone Fracture Successful Protocol Used In This Case Acepromazine at 0.05 mg/kg IV pre-medication 0.1 to 0.2 mg/kg IV oxymorphone Oxygen by mask was administered as soon as the dog relaxes Induction with isoflurane by face mask Intubation with continued inhalant maintenance Additional oxymorphone as indicated

21 Postoperative pain management includes: NSAID, i.e. Carprofen at 2.2 mg/kg BID (4.4 mg/kg SID), or Ketoprofen at 2 mg/kg SID Deracoxib at 4 mg/kg SID Opioid, i.e. Fentanyl patch Epidural duramorph Orthopedics Canine Long Bone Fracture

22 Orthopedics Cruciate Ligament Repair History: 1 year old, female Rottweiler 45 kg body weight ASA physical status I

23 Orthopedics Cruciate Ligament Repair Management options include: Butorphanol at 0.2 mg/kg IM + Medetomidine 10 to 15 µg/kg IM Followed in 15 minutes with induction of anesthesia with either propofol 2.2 mg/kg IV or thiopental 5 to 6 mg/kg IV to effect Intubation, anesthesia maintained with halothane, isoflurane or sevoflurane

24 Postoperative pain management: NSAID Orthopedics Cruciate Ligament Repair Repeat doses of either alpha 2 agonists or opioid agonist-antagonist as necessary Intra-articular nerve block

25 Opioid / Alpha 2 Synergism (Drug combinations may prolong duration of analgesia) Cross over study design using: 6 healthy dogs at 0.9% end-tidal ISO concentration Tail clamp at 15 minute intervals till noxious response Saline control Treatment Group Butorphanol (0.2mg/kg IM) Medetomidine (5.0 µg/kg IM) Butorphanol (0.2mg/kg IM) Medetomidine (5.0 µg/kg IM) + Grimm KA, et al. AJVR 2000; 61(1), Time Until Positive Response hours hours hours hours

26 Cancer - Canine History: 6 year old, castrated male Labrador Retriever 35 kg body weight Presented with: Abdominal mass ASA physical status II

27 Cancer - Canine Perioperative management included: 1.0 mg/kg IM morphine Followed in 15 minutes by induction of anesthesia with propofol at a reduced concentration of 2.2. to 4.4 mg/kg IV as necessary Anesthesia maintained with isoflurane Following induction of anesthesia the dog is prepared for an epidural block with bupivicaine and morphine

28 Consideration: Cancer - Canine Extensive involvement of the abdominal cancer (or in the case of osteosarcoma) prolonged pain may be expected The use of a transdermal fentanyl patch for perioperative and post-operative management is an option which can provide basal analgesia Rescue analgesics as needed

29 Caesarean Section - Canine History: 3 year old, female English Bulldog In pre-labor with a history of dystocia ASA Physical Status I

30 Caesarean Section - Canine Management options include: Premedication with an opioid agonist, i.e. Oxymorphone 0.1 mg/kg IV Fentanyl 0.01 mg/kg IV Anesthetic induction, i.e. Propofol at 3.3 to 4.4 mg/kg IV After intubation, anesthesia is maintained, with isoflurane or sevoflurane Following delivery of the newborn & anesthetic recovery, additional analgesics should be administered as needed for postoperative pain management

31 Caesarean Section - Canine Concurrent Pain Management Consideration: Epidural block for perioperative & postoperative management Oxygen Supportive care

32 Caesarean Section - Canine Supportive Protocol: Depressed puppies can be usually revived with the administration of a drop of sublingual naloxone, with or without sublingual doxapram hydrochloride to stimulate respiratory efforts

33 Head Trauma - Feline History: Intact male domestic shorthair 3.5 kg body weight ASA Physical Status III Major trauma to the head including fractured mandible, broken teeth, damage to the soft palate & hemorrhage

34 Head Trauma - Feline Management options include: Premedication & induction with diazepam 0.1 mg/kg IV & 2 to 4 mg/kg IV ketamine Following intubation, anesthesia is maintained with an inhalant. ( A mandibular nerve block for additional analgesia may be utilized.) Postoperative analgesia is maintained with butorphanol 0.2 mg/kg IM & 1.0 mg/kg IM ketamine, as needed during the first 24 hours postoperatively Note: Single dose subcutaneous 1 to 2 mg/kg or 2 mg/kg IM, to reduce inflammation during the first 24 hours (*ketoprofen per UK usage guideline)

35 Pain Management & Supportive Care

36 Treating Side Effects 1. Intubation, ventilation & oxygen administration for respiratory distress 2. Anticholinergics such as glycopyrrolate to avoid bradycardia 3. Tranquilizers and sedatives to reduce distress or delirium 4. Antagonists such as atipamezole or naloxone to reverse effects of alpha 2 & opioid agonists Butorphanol for partial opioid reversal

37 Protocol Development in Pain Management Preemptive analgesia Balanced analgesia Dose to effect Re-evaluate the patient

38 1. Preemptive Analgesia Dose early Dose before the first surgical incision Dose before the patient hurts Dose before the last dose wears off Balance the analgesic & anesthetic requirements

39 2. Balanced Analgesia Similar to balanced anesthesia Combination of complimentary methods or drug classes Maximize effectiveness and minimize side effects Analgesics Anesthetics PAIN

40 "Give until it helps! 3. Dose to Effect Medicate smartly. Make the most of your analgesic strategy Inadequate analgesia is wasteful and counter productive Adapt dosage to individual patient needs

41 Pain Management Includes Careful monitoring of vital signs including pain Use of medications NSAIDs Local or regional anesthesia Opioids Alpha 2 agonists Thorough nursing care Alteration of the environment Distraction and relaxation techniques

42 Detailed Case Reports in Perioperative Pain Management PAIN

43 Cases Kitty Feline Elective Surgery Katie Cruciate Ligament Repair Jada Abdominal Crisis Hambone Ear Canal Ablation

44 Kitty Feline Elective Surgery

45 Kitty 4 month old, female DSH, 3.3 kg body weight Presented for ovariohysterectomy & declaw ASA Physical Status I

46 Preanesthetic Medications Fentanyl patch (25 µg) applied following patient admission (12 hours before surgery) Premedicated intramuscularly with: Acepromazine mg/kg, 0.25 mg total Butorphanol 0.44 mg/kg Atropine mg/kg

47 Anesthesia Intravenous induction with mixture of ketamine (7.5 mg/kg) and diazepam (0.4 mg/kg) Anesthesia maintained with isoflurane in O 2 via endotracheal tube

48 Options: Postoperative Analgesia Hydromorphone 0.11 mg/kg IV at extubation Ketoprofen 1.5 mg/kg 24 hours post-op Fentanyl patch for total of 5 days Kitty one day post-op

49 Katie Cruciate Ligament Repair

50 Katie Signalment: Rhodesian Ridgeback Female spayed 6 year old

51 History Presented with a 3 month history of an intermittent weight bearing lameness of the left hind limb Had previously undergone surgery for a right cranial cruciate ligament rupture 3 years ago Owner suspected a similar injury in the contralateral limb

52 Preoperative Workup Complete physical examination Weight bearing left hind limb lameness Orthopedic examination Pain and instability of left stifle joint, a cranial drawer sign could be elicited CBC, biochemistry, electrolytes Within normal limits Preoperative stifle radiographs Moderate stifle effusion & degenerative joint disease

53 A diagnosis of left cranial cruciate instability was made and Katie was taken to surgery the following day..

54 Anesthetic Management Premedication: Hydromorphone (0.05 mg/kg IM) Acepromazine (0.1 mg/kg IM) Anesthesia induction: Propofol ( 4-6 mg/kg IV to effect) Anesthesia maintenance: Isoflurane in oxygen

55 The Procedure A morphine (0.1 mg/kg) / bupivacaine (1.1 ml/kg) epidural was administered preoperatively

56 The Procedure In addition, a preoperative intra-articular bupivacaine block (8 ml ) was administered into the stifle joint

57 The Procedure After final skin preparation, Katie was positioned onto the operating table

58 The Procedure A 15 cm medial skin incision was made

59 The Procedure A biradial saw was used to create a proximal tibial osteotomy A standard left TPLO plate was applied to the medial side of the tibia

60 The Procedure Soft tissues and skin were closed routinely Katie was taken to the recovery unit for postoperative monitoring

61 Recovery Period Anesthesia was discontinued, and Katie was maintained on 100% oxygen until extubation After extubation, hydromorphone (0.05 mg/kg IV) was administered Katie was closely monitored for signs of pain and discomfort for 24 hours post surgery

62 Postoperative Period Heart rate, respiratory rate, mean arterial blood pressure, cumulative pain scores, and visual analog pain scores were used to assess discomfort and pain Hydromorphone (0.05 mg/kg IV) was administered as needed throughout the 24 hour postoperative period

63 5 Hours Postoperatively Katie continued to rest comfortably in the ICU

64 24 Hours Postoperatively Katie left recovery and was moved to a run in the surgical ward Carprofen (Rimadyl 1.1 mg/kg PO, BID) was prescribed for the next 10 days to manage postoperative pain and inflammation

65 48 Hours Post-Surgery Katie weight bearing on her operative limb

66 50 kg body weight 6 year old Female spayed Great dane History: Jada Snake bite, ventral abdomen, 2 weeks prior to presentation Treated with 2 weeks of oral antibiotics (enrofloxacin) Now has weight loss, abdominal distension, fever, and lethargy

67 Patient Evaluation Physical exam: Severe abdominal distension Muscle wasting Labored breathing Decreased respiratory sounds

68 Diagnostic Tests: Patient Evaluation Anemia, leukocytosis with a degenerative left shift and 2+ toxic changes, thrombocytopenia, hypoalbuminemia, hyponatremia, hyperkalemia, increased AST, normal coagulaltion panel Radiographs: Mild bronchointerstitial disease, compromise of the thoracic cavity because of abdominal distension. Diffuse loss of abdominal detail and small intestines fluid filled Peritoneal centesis: Septic peritonitis with filamentous, gram negative bacteria, consistent with actinomyces (confirmed later on culture)

69 Patient Treatment IV fluids Normosol 15 ml/kg/hour Ampicillin 20 mg/kg IV q 6 hours Enrofloxacin 5 mg/kg IV q 12 hours Hetastarch 2.5 ml/kg IV in one hour for oncotic support Heparin 80 units/kg SQ q 8 hours to prevent DIC Nasal O 2 before and after surgery

70 Anesthetic/ Pain Management Pre-medication: Hydromorphone 0.05 mg/kg IV Midazolam 0.2mg/kg IV Ketamine 2 mg/kg IV Induction: Ketamine 6 mg/kg IV

71 Anesthetic/ Pain Management Anesthesia: (cont) Isoflurane in oxygen, at needed concentration Epidural nerve blocks: Duramorph 0.1 mg/kg

72 Intra-operative Support: Dopamine 10 µg/kg/minute for cardiovascular support Lidocaine 20 µg/kg/minute CRI

73 Surgery Abdominal exploratory, resection of abscessed body wall at location of snake bite (abscess had drained into abdomen), abdomen flushed with 12 liters of saline, and continuous suction drains placed in abdomen (4 drains) and abscess (1 drain) before closure

74 Postoperative Care Pain management: Hydromorphone IV 0.05 mg/kg q 4 hours for 4 treatments Lidocaine CRI continued at 25 µg/kg/minute for 2 days Control of infection: Ampicillin continued IV, then per os Abdominal drains maintained for 4 days after surgery Supportive therapy: Fluids IV: amount based on central venous pressure and fluid loss from drains

75 Hambone Ear Canal Ablation

76 Hambone 13 year old Male pug 11.0 kg body weight

77 History Bilateral otitis externa for 3 years intermittently treated with antibiotic/ steroid topical and oral steroids Three months prior to presentation, the left ear canal was full of purulent fluid and the tympanic membrane could not be visualized The ear canal did not respond to 2 months of flushing, topical cleansers, and a course of oral antibiotics Yeast dermatitis and otitis were diagnosed, and the dog was treated with clotrimazole otic with dexamethasone, and Nolvasan ear flushes

78 Special Examinations Two months later, the ears could be thoroughly examined and a mass was found in the left ear canal

79 Diagnosis Left sided facial nerve paralysis, dental tartar, mass in left ear at junction of horizontal and vertical canal. Diagnostics: Chronic severe otitis externa and media of the left ear with secondary osteomyellitis and probable cellulitis. Biopsy non-diagnostic because mass was hard and would not exfoliate. Owners concerned about postoperative pain!!

80 Surgery Treatment Total ear canal ablation and bulla osteotomy Pain Management Pre-emptive analgesia: Fentanyl patch 1 day pre-op (25 µg)

81 Perioperative Anesthetic Management Premeds: Hydromorphone 1 mg IV Midazolam 2.5 mg IV Atropine 0.01 mg/kg IV Induction: Ketamine 10 mg IV Maintenance: Isoflurane in O 2

82 Supplemental Perioperative Analgesia Intraoperative blocks: Bupivacaine 5 mg local block

83 Surgical Correction with Desirable Pain Management

84 Postoperative Analgesia Hydromorphone 1.0 mg IV at extubation Morphine 8 mg IM and acepromazine 0.25 mg IM PRN max q 2 hours Local analgesics if needed

85 Discharge Instructions Fentanyl patch to be removed on day 5 Carprofen 25 mg PO twice a day as needed for pain

86 Perioperative Anesthetic and Pain Management Improves Post-Operative Recovery

87 Provided by Ralph C. Harvey, MS, DVM, DACVAA Associate Professor Anesthesiology & Charles E. Short DVM, PhD, DACVAA, DECVAA Emeritus Professor of Anesthesiology & Pain Management College of Veterinary Medicine