Title: Intraoperative Hypotension
1Intraoperative Hypotension
- John A. Mattoni, M.D.
- SFGH
2Intraoperative Hypotension
- Case 39 yo female hairdresser with stab wounds
to anterior abdomen X5 - Vital signs stable in ED 113/73 86 18 100
- GCS 12 (E4,M6,V2)
- Hct 22, ABG 7.37/33/278, -6
- CXR Right hemothorax
- PMH - unknown
3Intraoperative Hypotension
- Preoperative
- Chest tube placed on right in ED (400cc out)
- 2units PRBC transfused in ED
- Abdominal ultrasound fluid in RUQ
- Pt remained stable. Observed in PACU 1hr while
2 other trauma cases finished (husband)
4Intraoperative Hypotension
- Operative
- Monitors standard, foley, radial arterial line
- Access bilateral 14 ga IV in place
- Induction Rapid Sequence with STP/SUX
- Pt remained stable after induction/intubation
- 130s/80s, 90s , 100
5Intraoperative Hypotension
- Operative (cont.)
- Soon after incision, BP dropped to 90/40 with
pulse 120s. - Liver laceration to left lobe noted, actively
bleeding - Stab wound to stomach X2
6Intraoperative Hypotension
- Hypotension - Differential Diagnosis
- 1. Inadequate inflow to heart
- 2. Decreased pump function
- 3. Decreased vascular resistance
7Intraoperative Hypotension
- Inadequate inflow to heart
- 1. Many Causes
- most common inadequate intravascular volume
- blood loss, third spacing, evap loss, fever, NG
suction, resp losses - relative hypovolemia venous pooling, positional
changes, surgical packs or traction - 2. Diagnosis
- urine output, tachycardia, CVP, PCWP
8Intraoperative Hypotension
- Decreased Cardiac function
- Myocardial depressant drugs volatile
anesthetics, B-blockers, CA channel blockers,
propofol, barbiturates, lidocaine - Arrhythmias
- Myocardial ischemia or infarct
- Hypocalcemia (rare)
9Intraoperative Hypotension
- Decreased Vascular Resistance
- Sympathetic blockade
- Neurogenic
- Drug effects
- Sepsis
- Anaphylaxis
10Intraoperative Hypotension
- Operative (cont.)
- Pt received 2u PRBC quickly
- BP responded to 110s/50, P110, 100
- However, initial (pre incision) ABG
7.30/30/496, -8, Hct 34
11Intraoperative Hypotension
- Operative (cont.)
- 30 min later, BP drops to 80/40, P125, 100
- Post transfusion ABG (5 min before above )
7.25/33/498,-12.8, Hct36 - No response to volume (crystalloid, PRBC) and
minimal response to phenylephrine or ephedrine
12Intraoperative Hypotension
- Operative (cont.)
- Surgeon reports some fluid had been seen in
pericardial sac - Anterior thoracotomy performed near parasternal
stab wound - Pericardium lacerated, heart normal, minimal
fluid in sac - CaCl given without response
13Intraoperative Hypotension
- Operative (cont.)
- Phone call from daughter into OR
- She has a
- LATEX ALLERGY
14Intraoperative Hypotension
- Operative (cont.)
- Epinephrine infusion started
- Benadryl 50mg given
- Hydrocortisone given
- Pts vital signs remained stable throughout the
rest of the OR course - Repeat ABG 7.34/33/353,-8, Hct 29
15Latex Allergy
- What is meant by latex allergy?
- The allergy is an IgE mediated reaction to the
soluble proteins or processing chemicals used to
produce latex products - Allergies to latex can be along the continuum
from contact dermatitis to localized or
generalized reactions, including anaphylaxis
16Latex Allergy
- High-Risk Groups
- 1. Pts with multiple surgical procedures
- myelomeningocoele, congenital GU tract anomalies
- spina bifida incidence 30-70
- 2. Health Care Personnel - up to 17
- 3. Other Occupational Exposure
- hair dressers, greenhouse workers, latex
manufact. - 4. Hx of hay fever, rhinitis, asthma or eczema
- 5. Food Allergy to tropical fruits, chestnuts,
stone fruits
17Latex Allergy
- Three types of reactions in latex allergy
- 1. Irritant contact dermatitis
- 2. Type IV hypersensitivity
- - skin rxn similar to poison ivy
- 3. Type I hypersensitivity
- - from hives and erythema to anaphylaxis and
cardiovascular collapse
18Latex Allergy
- Chemistry of Latex
- Natural Rubber Latex (NRL) is a complex mixture
of polyisoprene, lipids, phospholipids and
proteins - Many chemical added (preservatives, accelerators,
antioxidants, vulcanizing) - Protein content responsible for majority of
allergic rxns to latex (over 240 proteins)
19Latex Allergy
- Irritant Contact Dermatitis
- most freq rxn to latex
- direct action of latex and other chemicals
- not mediated by immune system, not a true allergy
- deterioration in skin integrity enhances
absorption of latex protein allergens and is
believed to accelerate onset of allergic rxns
20Latex Allergy
- Type IV Delayed Hypersensitivity
- also called contact dermatitis or delayed
hypersensitivity - skin rxn like poison ivy
- appears 6-72 hrs after initial contact
- most anaphylactoid reactions are Type IV
- cell mediated depend on antigen reactive cells
(rather than antibodies)
21Latex Allergy
- Type IV Delayed Hypersensitivity
- mild dermatitis to skin blisters
- 84 of immunologic responses to gloves are Type
IV - Not all Type IV progress to Type I
- 79 of Type I pts had Type IV symptoms
22Latex Allergy
- Type I Immediate Hypersensitivity
- Also called IgE mediated anaphylactic rxn
- Requires prior sensitization
- Reactions usu within minutes of exposure
- Symptoms from mild to life-threatening
23Latex Allergy
- Type I Immediate Hypersensitivity
- Antigen induces production of an antibody of the
IgE class. Re-exposure to antigen causes
degranulation of mast cells and basophils through
cross linking, which triggers a cascade of
events, including release of histamine,
arachidonic acid, leukotrienes and
prostaglandins.
24Latex Allergy
- Management of Latex-Sensitive Patients
- 1. Coordination of care between anesthesia,
surgical, nursing, and other support teams to
remove latex exposure - 2. First Case of the day - aerosolized latex
antigen lowest level in OR suite - 3. Signs signifying Latex Allergy posted
- 4. Latex-free cart should accompany patient
25Latex Allergy
- Management of Latex-Sensitive Patients
- 5. Medical alert bracelet should be obtained
- 6. Pharmacological prophylaxis
- controversial
- included diphenhydramine, H2 blockers, and
steroids - leaves anaphylaxis as the first evidence of
allergic rxn - not universally successful in preventing latex
anaphylaxis
26Latex Allergy
- Management of Latex Sensitive Patients
- 7. Medications should not be drawn up or
administered through rubber caps or diaphragms
and should not remain in contact with the rubber
in the syringe plunger for long periods of time - 8. Wash hands to remove any traces of powder or
latex
27Latex Allergy
- Treatment of An Allergic Reaction to Latex
- Contact Dermatitis and Type IV reactions can
usually be treated with avoidance and topical
corticosteroids - Treatment of a systemic reaction to latex same as
for other systemic allergic reactions - mild reactions (hay fever) - respond to
antihistamine - hives - antihistamines and systemic steroids
- anaphylaxis - formal treatment protocol
28Latex Allergy
- Acute Management
- 1. Call for help, notify surgical and OR staff
of possible latex reaction - 2. Remove all latex from surgical field
- 3. Change gloves to non-latex
- 4. Discontinue all antibiotic and blood admin.
(to rule out other forms of allergic rxns) - 5. Maintain airway (intubate as indicated) and
administer 100 O2
29Latex Allergy
- Acute Management (cont.)
- 6. Infuse 25-50 ml/kg of crystalloid or colloid
as indicated - 7. Administer epinephrine
- IV 0.1 mcg/kg (10 mcg in adult)
- SQ 300mcg (0.3mg)
- Endotracheal 5-10 times IV dose (50-100mcg)
- 8. Consult allergist, draw levels of mast cell
tryptase, complement C3/C4, and histamine
30Latex Allergy
- Secondary Therapy
- 1. Antihistamine (controversial)
Diphenhydramine 1mg/kg IV or IM (50mg max dose)
Ranitidine 1mg/kg IV (max dose 50 mg) - 2. Glucocorticoids Hydrocortisone 5mg/kg
initially, then 2.5mg/kg q 4-6 hrs.
Methylprednisolone 1mg/kg initially and 0.8 m/kg
q 4-6 hours - 3. Aminophylline for bronchospasm load 5mg/kg,
then 0.4 - 0.9 mg/kg/hr
31Latex Allergy
- Secondary Therapy (cont.)
- 4. Inhaled Beta 2 agonist for bronchospasm
- 5. Continuous catecholamine infusion for BP
support - Epinephrine 0.02-0.05 mcg/kg/min (2-4 mcg/min)
- Norepinephrine 0.05 mcg/kg/min (2-4 mcg/min)
- Dopamine 5-20 mcg/kg/min