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Co-Existing & Basic Principles 2016 * > Immunity & Infections > Flashcards

Immunity & Infections Flashcards

1
Q

HIV Systemic Effects

Neurologic

A

CNS = HIV “reservoir”

  • Sensory neuropathy: numbness, tingling, painful dysesthesias and paresthesias
  • Encephalopathy or AIDS dementia complex: cognitive, motor, and behavioral changes
  • Opportunistic infections/ malignancies
  • HAART related cerebral vascular disease

​perform good baseline neuro exam, consider inflamm demyelinization sim to MS pts, weigh risks /benefits of regional if pt has severe neuropathy

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2
Q

HIV

Systemic Effects

Respiratory

A

Respiratory (Infectious)

  • PCP
  • Bacterial pneumonia
  • TB
  • Aspergillosis
  • CMV
  • Oral/pharyngeal candidiasis
  • Kaposi’s sarcoma
  • Herpes
  • direct HIV pulmonary destruction
    • leads to respiratory failure, PTX, chronic lung disease (much like emphysema)
  • Tracheobronchial/great vessel compression w/ adenopathy, endobronchial Kaposi’s (massive hemoptysis)

​consider if they have an active infection. Postpone elective sx until after treatment.

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3
Q

HIV

Systemic Effects

Cardiac

A

Cardiac (chronic trophic viral infection + co-infection/drug toxicity related)

  1. Pericarditis
  2. pericardial effusion
  3. myocarditis (late stages of infection)
  4. dilated cardiomyopathy
  5. endocarditis (IVDA)
  6. pulmonary HTN
  7. thromboembolus
  8. CAD/MI
  9. development of abdominal aortic aneurysms and aortic dissection
  • 50% of HIV + patients have abnl echo
  • HIV has a high affinity for myocardium
  • Protease inhibitors in particular are problematic – advance atherosclerosis and diastolic dysfunction (25% HIV + have pericardial effusions)
  • PCP less common now with advances in the pharmacologic treatment of the disease
  • chronic PI therapy likely have hyperlipidemia (↑ LDL & ↓HDL)
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4
Q

HIV Systemic effects

Hematology

A
  • drug toxicity/bone marrow suppression
  • Leukopenia, lymphopenia, thrombocytopenia, anemia

check CBC & coags

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5
Q

HIV Systemic Effects

GI, Renal, Endocrine

A
  • diarrhea, proctitis, GI bleeding, cholecystitis, anorexia, N&V, dysphagia (Candida albicans,CMV), esophagitis, Hepatitis B and C
  • Nephropathy, ATN, nephrotic syndrome
  • Adrenal insufficiency (end stages)
  • Glucose intolerance (HAART)

review preop labs for electrolyte abnormalities, hypoalbuminemia

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6
Q

classes HAART therapy

anesthetic drug management

A

Currently there are 6 Categories

  1. Nucleoside reverse transcriptase inhibitors
    • Inhibition of CYP 450 system
    • zidovudine + corticosteroids = severe myopathy, respiratory muscle dysfunction
  2. ​Protease Inhibitors
    • ​​Inhibiton of CYP 450 3A4
    • fentanyl and versed have increased effects
      • ​more sedation, confusion, respiratory depression
      • start with low dose and titrate carefully
      • fentanyl → clearance decreased by 67%
    • AVOID drugs w/active metabolites →LIFE THREATENING
      • Meperidine → toxic metab → normeperedine (seizures)
      • Amioderone →arrythmials →E1/2 = 29 days
      • Diazepam → prolonged half life
  3. ​Non-nucleoside reverse transcriptase inhibitors
    • ​​Delavirdine = Inhibits CYP 450
      • (increased sedatives, warfarin, CCB)
    • Nevirapine = INDUCES CYP 540 by 98%
      • ​go through NMB very fast
  4. Integrase strand transfer inhibitors → appear well tolerated
  5. Chemokine Receptor 5 antaonists and entry inhibitors
    • ​also appear well tlerated
    • may interact with the clearance and drug effects
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7
Q

HAART therapy

considerations in anesthesia

A
  • institution of HAART within 6 months of anesthesia & surgery actually ↑ M&M
  • Heart therapy effects every system in the body
    • Respiratory → opporunistic respiratory infections
      • tracheobronchial great vessel compression and adenopathy (hemoptysis/difficult airway)
    • Cardiac → consider those on HAART as CAD risk (especially protease inhibitors)
      • Cerebral vascular disease → stroke
      • pericardidtis, pericardial effusions, dialated cardiomyopathy, endocardidits, pulm HTN, thromboembolism
      • Development of abdominal aortic aneurism and aortic disection
      • 50% have an abnormal ECHO
    • GI →
      • N/V/D, proctitis, GI bleed, cholecyctitis, anorexia, dysphagia, candidia, CMV, Hep B & C
    • Renal → Nephropathy, ATN, Nephrotic syndrome
    • Endocrine
      • Adrenal insufficinecy → Steroids?
      • ​Glucose intolerance (esp. protease inhibitors)
    • ​Hematologic
      • Leukopenia, lymphopenia, thrombocytopenia, anemia (CBC, coags)
    • Neurologic
      • sensory neuropathies
      • ​encephalopathy or AIDS dimetia complex
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8
Q

Ritonavir (Protease inhibitor) & Interactions with Anesthetic Drugs

A
  • Midazolam: ↑ effects
    • sedation, confusion, respiratory depression
    • Small carefully titrated IV dosing O.K. (just do it very slowly and carefully- working in very tiny incraments one consents are sighned)
  • Fentanyl: ↑ effects
    • sedation, confusion, respiratory depression
    • Start with low dose & titrate to pain
  • Avoid (pronounced effects → life threateningàdue to prolonged clearance)
    • Meperidine → metabolized to normeperidine → which affects CNS (seizures) even with one dose may end up with a toxic dose
    • Amiodarone (arrhythmias) → E½ life = 29 days - may not always think about this with ACLS but is something to keep in the back of your mind
    • Diazepam → long ½ life
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9
Q

HIV and Lab results

A
  1. CD4 counts
    • low/ominous
    • high/encouraging >500-700 mm3
    • if low, maybe want them to go and change drug regimen prior to surgery
  2. T lymphocyte counts
    • low/ominous 200 cells/mg
  3. Viral load evaluates therapy efficacy but unclear significance to anesthetic outcome – wont tell us how they will do under anesthesia, drugs will still effect all other systems of these patients
  4. CBC
  5. BMP
  6. coagulation studies
  7. CXR
  8. EKG+/- ECHO
  9. PFTs
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10
Q

HIV

General Anesthesia

A
  • Extensive use of volatile agents has refuted earlier caution against use
    • ​Monitor closely for myocardial depression r/t anesthetic agents
  • Biggest factor to consider = underlying pulmonary disease (avoid intubation if extensive)
  • Carefully titrate anesthetics considering co-existing anemia, autonomic neuropathy, adrenal insufficiency, and upper airway obstruction/difficult airway w/supraglottic Kaposi’s sarcoma
  • Be careful with Succinylcholine with peripheral neuropathy, myopathy, spinal cord involvement
  • Long term effect of GA and opioid induced immunosuppresion unknown
    • ​Immunosuppression from GA occurs within 15 minutes of induction and persists for 3-11 days. Psychological stress.
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11
Q

HIV

Regional

A
  • Once controversial now routinely used– early concerns about spreading HIV to CSF unfounded
  • Use of RA in parturients well studied – no abnormal neurologic, immunologic or infectious complications noted
  • Contraindications:
    • coagulopathy
    • infection at the site of block placement
    • focal neurologic lesions w/increased ICP
  • Decreases IV opioid requirement (helps avoid issue of decreased IV opioid clearance w/protease inhibitors)
  • Infection control, maintain sterile conditions!
  • Epidural blood patch can be used to treat PDPH - try other methods 1st
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12
Q

HIV/AIDS

Preoperative Prepration

A
  1. Follow universal precautions (as with all patients)
  2. Routie sterilization procedures
    • Sodium hypochlorite destroys HIV
  3. Careful reveiw of the progression of the disease process and organ involvement
  4. What is their durg regimen and side effects?
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13
Q

TB signs and symptoms Review

A
  1. Non Productive cough (74%)
  2. Weight loss (71%)
  3. Feaver and night sweats (30%)
  4. Malaise (30%)
  5. hemoptysis (bloody cough) and chest pain (19%)
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14
Q

TB first line treatment and side effects

A

Anti TB drugs have decreased mortality by 90%

Isoniazid and Rifampin are the most use combinations

  1. Isoniazid
    • Hepatotoxicity, possible renal toxicity, drug interactions
    • peripheral neurotoxicity
  2. Rifampin
    • ​hepatotoxicity, renal toxicity, drug interactions
    • GI upset, anemia, thrombocytopenia
  3. Pyrazamide
    • ​Hepatotoxicicty
    • GI upset, arthralgia
  4. Ethambutol → occular neuritis
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15
Q

when can a TB patient have an elective surgery

A
  1. 3 negative sputum smears
  2. improving symptoms
  3. clear chest X-ray

! must meet ALL 3 requirements to go to surgery !

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16
Q

Prophylactic antibiotics in the Normal Patient

A
  • The goal of therapy is prevention of surgical site infection
  • They should be given within 1 hr before incision
  • consider larger doses in obese pateints
    • (2g of ancef instead of 1g)
  • Redose if surgery > 4 hrs
  • The antibiotic is tailored to resistance patterns
    • ​of the local area
    • and to the surgical procedure
17
Q

besides antibiotics how else do you prevent infections

A

AVOID:

  • Hypothermia
    • Cold pts develop infections at a much higher rate!
    • They also bleed more!!!
  • Hypocarbia
    • promotes infection causes vasoconstriction which decreases blood flow
    • make sure you are not hyperventilating the patient
  • Hypoxia
  • Hyperoxia (free radical damage)
  • Hyperglycemia
  • Blood transfusions
    • if you can avoid it is its ideal – they are at higher risk to get an infection
18
Q

Endocarditis prophilaxis - who gets it?

A

Patients who have:

  • Artificial heart valves
  • Prior history of endocarditis
  • Some congenital cardiac malformations
    • Cyanotic congenital heart disease (birth defects with O2 levels lower than normal), that has not been fully repaired, including children who have had a surgical shunts & conduits, or those with prosthetic device with a repaired
    • A congenital heart defect that’s been completely repaired with artificial material or a device for the first six months after the repair procedure
    • Repaired congenital heart disease with residual defects, such as persisting leaks or abnormal flow at or adjacent to a prosthetic patch or prosthetic device
  • Damaged heart valves
  • Hypertrophic cardiomyopathy
  • A cardiac transplant which develops a problem in a heart valve

AND undergoing the following surgeries:

  • Dental or oral with perforation of the oral mucosa likely (dental extractions)
  • Invasive procedures of respiratory tract where respiratory mucosa perforated
    • I.e. Tonsillectomy, adenoids, abscess drainage
  • Procedure involving infection of GI/GU tract, skin/musculoskeletal tissue (not needed with routine procedures; colonoscopy, upper endoscopy, cystoscopy (removal of renal stones) or even bronchoscopy)
  • Cardiac Surgery
  • Hepatobiliary procedures with high risk of bacteremia
19
Q

When and what do you give for endocarditis prophylaxis

A

give up to 2 hours after if patient misses pre-procedure

  • Ampicillin 2 g IV (50 mg/kg pediatrics)
  • Cefazolin (Ancef) 1 g IV (50 mg/kg pediatrics)
  • Ceftriaxone (Rocephin) 1 g IV (50 mg/kg pediatrics)

If allergic to penicillins

  • Clindamycin 600 mg IV (20 mg/kg IV pediatrics)
20
Q

Precautions for emergency surgery in a patient with TB to minimize the risk of disease spread

A
  1. Must wear N95 mask
    • Patient → anytime they are outside the isolation room
    • Health care workers → must be fit tested
    • if unable to get adequate fit can be covered with a powered air purifying respirator
  2. ​OR considerations
    1. ​ORs never negative pressure = surgical site infection risk
      • ​keep pt in neg. pressure room whenever possible
    2. An OR physically seperated from other areas is ideas
    3. OR doors should be shut
    4. Close the OR after the case until 99.9% turnover of air
    5. Patient will recover in the OR if the PACU does not have a negative pressure room
  3. ​Anesthesia machine considerations
    1. ​Use a dedicated anesthia machine and ventilator
    2. Filters
      • ​High efficiency particulate filter→ between the y connector and the patient
      • Bacterial filter→ on the exhalation limb (decreases ambient room exposure)
21
Q

What are the main types of Allergic Reactions?

A
  1. Type I
    • IgE, mast cell basophils
    • anaphylaxis and immune mediated hypersensitiveity
  2. Type II
    • IgG, IgM binding of antigen/drug
    • alternate pathway, kinin or plasmin activation
    • ​Cytotoxic-complement activation
    • Usually manifests as hemolytic anemia, thrombocytopenia, neutropenia
  3. Type III
    • ​​Dammage secondary due to immune complex formation or deposition
    • Glomerularnephritis, vasculitis, arthralgias
  4. Type IV
    • ​​T-lymphocyte mediated
    • delayed hypersensitivity type
  5. Chemical mediator with no antigen-antibody reaction
    1. mast cells and basophils activate in a non-immune mediated reaction
    2. this is an ANAPHALACTOID reaction
    3. examples MR, Meperidine, Morphine
22
Q

Anaphylactoid Reaction

what is it and prophylaxis

A

Anaphylactoid Reaction

  1. manifests as histamine release
  2. Magnitude is related to total dose of drug administered & rate of infusion
    • basophils release histamine in response to drugs such as muscle relaxants, opioids, & protamine
    • Certain patients are susseptable to this type of reaction
    • Hypotnesion is unlikley unless histamine concentration DOUBLES

Prohylaxis​

  1. Corticosteroids
    • Decadron
  2. H1 and H2 antagonist
    • decrease histamine release
    • ​Ranitidine, Benadryl
23
Q

Anaphylaxis

A
  • IgE mediated response
  • life threatening
    • Extravasation of up to 50% of intravascular fluid volume into the EC space possible
  • CV issues are the first sign
    • hypotension 1stsign (d/t vasodilation)
  • bronchospasm - seen as increased PIP
  • edema and airway swelling are late signs
24
Q

Anaphylaxis: Common Offenders

A
  1. Antimicrobial agents
    • PCN → 90% of all allergic reactions & 97% of fatal reactions
  2. Anesthetics
    • All anesthetic agents can cause anaphylactic reactions with the exception of ketamine & benzos
    • Thiopental has a low risk, but a very high mortality if they have an anaphylactic reaction
  3. Radiocontrast dyes
  4. Foods
    • I.e. peanuts
  5. Insect venoms
    • Bee allergy
25
Q

Anaphylaxis: Anesthetic agents

A
  1. Opioids → D/t histamine release
  2. Local Anesthetics →esters more likely than amides
  3. Induction agents →
    • Consider ketamine to prevent reaction in high risk patients
  4. Muscle relaxants
    • 50-60% of intra-op anaphylaxis occurances
    • actually much more likely to be casing than an antibiotic
  5. Volatile anesthetics
  6. Antibiotics (10-15%) →
    • Penicillin 90% of all allergic reactions + 97% of fatal reactions
  7. Blood → even with crossmatch (3% of patients)
  8. Dextran/Hetastarch
  9. protamine
    • seafood & salmon allergy
    • NPH insulin
  10. Vascular grafts → DIC more than anaphylaxis
  11. Latex → 15% periop
26
Q

Anaphylaxis: Differential Diagnosis

A

(first think…what could cause or be a manifestation of hypotension)

  1. Arrhythmia → Bradycardia → hypotension → decreased coronary profusion
  2. May look like an MI (ST changes?)
  3. CVA
  4. Hemmorage (may also cause hypotension)
  5. Vasovagal reaction
    • ​​ (anything that decreases venous return, uterine manipulation, SVC compression
  6. Pericardial tamponade

​(Then think anything that couls cause decrease O2 or increaseCO2)

  1. Pulmonary embolism
  2. Pneumothorax (high peak inspiratory pressure)
  3. Asthma → shouldn’t produce immediate cardiovascular collapseAspiration
  4. Pulmonary edema
  5. Postextubation stridor​

(Then the others that dont quite fit!)

  1. Venous Air embolism
  2. Medication overdose
  3. Sepsis
27
Q

Anaphylaxis: Signs & Symptoms

A
  • Flushing, urticaria (often missed d/t drapes)
  • Rapid onset CV collapse often 1st sign →
    • myocardial ischemia & dysrhythmias
  • Hypotension → up to 50% of the intravascular fluid moves to extracellular fluid secondary to capillary permeability changes + leukotrienes are negative inotropes)
    • this happens within minutes
    • Suspect anaphylaxis with sudden hypotension, +/- bronchospasm, following IV drug administration
  • Bradycardia may occur especially with muscle relaxants
  • Difficult intubation → laryngeal edema
    • (usually later but if they have an LMA/ or masking you will need to intubate immediately because it will get worse)
  • ↑ PIP or inability to ventilate → bronchospasm
    • first measure = ↑ inhaled anesthetics
    • could use: Ketamine → propofol → epi

All could work in severe situation

28
Q

anaphylaxis and antibiotic considerations

A
  1. Most common offenders include:
    • β-lactam (PCN, cephalosporins)
    • quinolones
    • sulfonamides
    • vancomycin
  2. ​​​Prior to administration
    • look at patients skin for pre-existing rash or skin condition
    • If they develop a rash = may be a reaction to abx
  3. ​Patients with a history of allergy (food, asthma, drugs)
    1. ​have increased incidence of anapylaxis
    2. may be genetic predisposition to increased IgE antibodies
  4. ​If someone has a PCN allergy:
    • ​they are 3-4x more likely to have an allergic reaction to ANY drug!
  5. ​NKDA/previous unevetntful exposure does not mean no allergy
    • ​Often one exposure needed to make IgE
    • It is the subsequent exposure that is the problem

​

29
Q

Anaphylaxis: Prompt Intervention

A
  • Communication (let everyone know → surgeon, additional personnel)
    • should stop the case immediately until stable again
  • Stop administration of likely agent(s)
  • Oxygenation
  • Elevate legs if possible to promote blood flow to central circulation
  • Volume infusion → need at least 10-25 ml/kg
    • Colloids fluids (10 ml/kg) are preferred to crystalloid fluids (colloids may stay in the intravascular space more)
    • Fluids boluses over 20 minutes
30
Q

Anaphylaxis: Pharmacology

A
  • Epinephrine – (always always start with epi but sometimes it does fail)
    • Blocks inflammatory mediator release from sensitized cells
    • Restores cell membrane permeability
    • β-agonist effect = relaxation of bronchial smooth muscle, ↑ BP & ↑ inotropy
    • β2 → bronchodilation, ↓ histamine release from mast cells; also best to revers bronchospasm
    • β1 → will help heart compensate
    • α1 stimulation → vasoconstriction & restore vascular integrity
  • Adult IV: 10 mcg-1 mg titrate q 1-2 minutes
  • Start with 10 mcg then double with each repeated dose
  • Children: 1-10 mcg/kg titrate q 1-2 minutes
31
Q

Anaphylaxis: if resistant to epinephrine

A
  • Glucagon: 1-5 mg bolus + infusion 1-2.5 mg/hr
    • ↑ cAMP promotes inotropic activity and helps with the bronchoconstriction
  • Norepinephrine: 0.05-0.1 mcg/kg/min
    • will not help the bronchospasm situation – but will help in shunting blood to central areas –emergency drug
  • Vasopressin: 2-10 unit bolus + infusion 0.01-0.1 unit/min infusion
    • moves blood to central circulation
32
Q

Anaphylaxis: secondary Pharmacology

A

Not necessarily life saving but will help slow down or stop reaction causing anaphylaxis

  • β2 agonists
    • albuterol if patient is still moving air
  • Histamine antagonism
    • Diphenhydramine (IV)(0.5-1 mg/kg IV) with Ranitidine 50 mg IV → better for prevention than for tx.
    • H1 & H2 need to be blocked together - has the best effect
  • Corticosteroids:
    • Enhances β-effects of other agents
    • Inhibits arachidonic acid release (↓ leukotrienes & prostaglandins)
    • Reduced activation of the complement system
    • Hydrocortisone is favored 250 mg IV
      • (Methylprednisolone also OK 80 mg IV)
    • Children:
      • hydrocortisone 50-100 mg &
      • methylprednisolone 2 mg/kg
    • Get them on board as soon as possible - wont see immediate effects
33
Q

Septic Patient - Anesthesia Optimization Goals

A

Delay case if not an absolute emergency

  1. Normal temperature
  2. Normal blood glucose
  3. MAP >65 mmHg
  4. CVP 8-12 mmHg
  5. Hgb 7-9 g/dL
  6. Urine output adequate
  7. Normalized pH
    • correct metabolic acidosis - Plasmalite or Normasol- better compared to LR and NS because they are right at physiologic pH – it is maintained MUCH easier
  8. Mixed venous O2 Sat >70%
  9. Lower VT 6-8 ml/kg → to prevent barotrauma
  10. PIP <30
  11. Prevent additional infection
34
Q

Septic pt and epiduals

A

Don’t even try

Absolute contraindication to do an epidural anesthesia

  • Especially with hemodynamic instability → patient may not tolerate ↓ SVR
  • Epidural abscess if bacteremic blood introduced into epidural space
35
Q

Sepsis

What is it?

Anesthesia for the septic patient?

A

Sepsis Definition

  1. Sepsis is a large term representing a spectrum of diseases where there are pathogenic microorganisms in the body
  2. Severity depends on organ involvement and the extent of systemic inflammatory resposnse

Anesthesia management: Intervascular fluid and hemodynamic status guides management

  1. Pre-op focus
    1. ABG, Vital Signs, mental status, vasopressors, sedation, pain management
    2. Need at least 2 large bore IVs
    3. Make sure PRBCs are in OR refrigerator (physically look!)
  2. Monitors
    1. Standard +
    2. A-line PRE induction
    3. CVP/PA (lower threshold if TEE available)
36
Q

Anesthesia for the septic patient

Induction

A

Goal = maintain SVR

  1. No specific ideal technique
  2. agents that will help maintain SVR
    • Etomidate (conster the risk of adrenal supression)
    • Ketamine
  3. Consider length of immobility before administering Succinycholine d/t possible hyerkalemian
37
Q

Anesthesia for the septic patient

Maintinence

A

Goal is to maintain SVR

  1. No Ideal technique
  2. Fluid resuscitation (bolus)
    1. crystalloind 500-1000mL
    2. colloid 300-500mL
  3. Inotropic or vasoconstricter support if needed
    • Epi
    • Norepi (first on algorythm 0.05-0.5 mcg/kg/min)
    • Dopamine
    • Dobutamine
    • Vasopressin
  4. Consider hydrocortisone for unresponsive shock
38
Q

Anesthesia for the septic patient

Emergence

A

they will likely remain intubated and go to the ICU

Co-Existing & Basic Principles 2016 * (21 decks)

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