Transcript Factors Influencing the Extent of the Inflammatory Response to

Factors Influencing the Extent
of the Inflammatory Response
to Cardiac Surgery
Eugene Yevstratov MD
2003
Preoperative Factors
• Preexisting disorders
• Disordered cytokine balance
• Patients with preoperative left
ventricular disfunction
undergoing CPB
• Poorly controlled diabetes
Perioperative Hemodynamic
Factors
• Perioperative hemodynamic
instability
• Low cardiac output syndrome
• Postoperative splanchnic
hypoperfusion
• Splanchnic ischemia
Anesthetic Techniques
• Thoracic Epidural Anesthesia
• Lung Management during
Cardiopulmonary Bypass
• Anesthetic Agents and Adjuvant
Drugs
Opioids
DRUG
Fentanyl
Morphine
Meperidi
ne
Codeine
Dose Interv
al
(mg)
.05- 15-30
IV
0.100 min
Rou
te
Duration
(hr)
Infusion
Rate
Onset
(min)
50-100
mcg/h
1-2
0.5-1.0
-
15-30
4-5
2-3
4-5
IV 10-30 2-4 hrs
10-50
mg/hr
1-2
2-4
IM 50-100 4-6 hrs
-
30-45
4-6
PO 30-60 4-6 hrs
-
20-30
4-6
IM
-
15-30
-
IM
2-10
IV
2-10
60
4 hrs
2-4 hrs 1-4 mg/hr
2-3 hrs
Recommendations for Opioids
1.Morphine is the preferred analgesic
agent for critically ill patients.
2.Fentanyl is the preferred analgesic
agent for critically ill patients with
hemodynamic instability and for
patients manifesting symptoms of
histamine release with morphine or
morphine allergy
3.Hydromorphone can serve as an
acceptable alternative to morphine
NOT RECOMMENDED
1.MEPERIDINE has an active metabolite,
normeperidine, that may accumulate and produce
central nervous system excitation.
2.Opiate agonist-antagonist (nalbuphine,
butorphanol, buprenorphine) have a plateau
effect.
3.NSAID drugs have no analgesic advantages
over opioids and have side effects such as GI
bleeding, bleeding secondary to platelet
inhibition, and the development of renal
insufficiency
Benzodiazepines
DRUG
T1/ metabolite
2
t/1/2
bolus dose
Chlordiazep
oxide
530
14-95
25-50 mg
(70kg)
Diazepam
2050
30-200
1-5 mg
Lorazepam
Midazolam
infusion
onset
(min)
duration
(hr)
-
1-5
.25-1.0
-
1-5
.25-1.0
40
12-24
1-5
2
.05mg/kg upto 0.025
10(max
mg/kg/hr
20 *none*
2mg)
112
1-2
upto 0.05
.5 to 10 mg/kg/hr
Recommendations for sedation
1.Midazolam or propofol are the preferred
agents only for short-term (<24 hrs) treatment
of anxiety in the critically ill adult.
2.Lorazepam is the preferred agent for the
prolonged treatment of anxiety in the
critically ill adult.
3.Haloperidol is the preferred agent for the
treatment of delirium in the critically ill adult
NOT RECOMMENDED
1.Etomidate, used long-term, is associated
with adrenocortical suppression and
increased mortality.
2.Ketamine increases blood pressure, heart
rate, and intracranial pressure
3.Barbiturates lack amnestic and analgesic
properties and produce myocardial
depression and vasodilation that commonly
result in tachycardia and hypotension
Propofol
Propofol may preserve hepatosplanchnic blood flow
during CPB, thereby aiding maintenance of the
mucosal barrier. It alters the balance between
proinflammatory and antiinflammatory cytokines,
increasing production of the antiinflammatory
cytokine IL-10 and IL-1ra, while decreasing
neutrophil IL-8 secretion, and scavenges reactive
oxygen species. Low concentrations of propofol
reduce neutrophil uptake in the coronary circulation
following myocardial ischemia and reperfusion.
Propofol impairs several aspects of monocyte and
neutrophil function, including the respiratory burst,
polarization, chemotaxis, ect....
Sodium thiopental
Sodium thiopental impairs the neutrophil
respiratory burst,polarization, chemotaxis,
adherence, phagocytosis and killing,and coronary
uptake of neutrophils following myocardial
ischemia and reperfusion. At therapeutic
concentrations, thiopental also inhibits the
monocyte respiratory burst. In high
concentrations thiopental affects Escherichia coli
clearance in vitro and neutrophil and monocyte
phagocytosis. The effect of thiopental on the
respiratory burst of neutrophils appears less
pronounced compared to propofol.
Ketamine
Ketamine attenuates the increase of serum
IL-6 concentrations during and following
CPB and reduces coronary uptake of
neutrophils following myocardial ischemia
and reperfusion.Ketamine affects E. coli
clearance and neutrophil and monocyte
phagocytosis in vitro, although only in high
concentrations.Methohexitone has only
minimal effects on the respiratory burst of
neutrophils in vitro.
Morphine
Morphine down-regulates the activity of lymphocytes,
granulocytes, and macrophages, and suppresses the
antibody response. Microinjection of morphine into
the lateral ventricle of the rat induces pronounced,
dose-dependent reductions in lymphocyte
proliferation to T- and B-cell mitogens, natural killer
cell cytotoxicity, and the production of IL-2 and
interferon- .Morphine also increases the secretion of
CRH, ACTH, and glucocorticoids, i.e., substances with
inhibitory effects on the immune system. Certain
immunomodulatory actions of morphine, including
NO release and inhibition of cell adhesion, appear to
be mediated specifically via the 3 receptor
Fentanyl
Fentanyl increases concentrations of IL-1ra
in in vitro monocyte cultures. In an isolated
blood primed CPB circuit, fentanyl
increased CD11b, augmented the reduction
in lymphocyte HLA-DR expression, and
attenuated the increase seen in monocyte
HLA-DR expression. However, fentanyl,
unlike morphine, appears to lack the ability
to bind to the 3 receptor, diminishing its
ability to down-regulate the inflammatory
response to CPB.
Midazolam
Midazolam, the best studied benzodiazepine, has
little influence on host defense mechanisms.
Midazolam decreases neutrophil IL-8 secretion in
response to lipopolysaccharide but does not alter
IL-8 production.Midazolam reduces postischemic
uptake of neutrophils in the coronary circulation
following myocardial ischemia and reperfusion.
Midazolam, at clinically relevant concentrations
in vitro, does not attenuate neutrophil
polarization and has minimal effects on the
neutrophil respiratory burst,neutrophil
phagocytosis, and clearance of E. Coli.
Sevoflurane, isoflurane, enflurane
Sevoflurane, isoflurane, and enflurane decrease
proinflammatory cytokine (IL-1 , TNF- ) release by
human peripheral mononuclear cells in vitro. Isoflurane
decreases alveolar macrophage phagocytosis and
microbicidal function to a greater extent compared with
propofol. Halothane, isoflurane, and enflurane attenuate
free radical–mediated myocardial injury. Isoflurane and
halothane (but not sevoflurane) appear to attenuate
hydroxyl radical production in the ischemic rat
heart.Sevoflurane and isoflurane and halothane reduce
neutrophil and platelet uptake in the coronary circulation
and preserve cardiac function following myocardial
ischemia and reperfusion.This effect is mediated at least in
part via reduced neutrophil expression of the adhesion
molecule CD11b
Clonidine
Clonidine appears to exert antiinflammatory actions in
such diverse areas as acute pain models, in extrinsic
asthma,and angiotensin-converting enzyme inhibitor–
induced inflammation. It appears that the
antiinflammatory action of clonidine is a property of 2
adrenoceptor activation. Furthermore, 2 adrenoceptor
agonists may regulate cytokine production via
stimulation of 2 receptors on macrophages to augment
TNF- release in response to endotoxin. While use of
clonidine during CABG does not appear to influence
the perioperative stress response, its
immunomodulatory effects in the context of CPB
remain to be characterized.
Surgical Factors
• Proinflammatory cytokine concentrations in
patients undergoing heart transplantation
are greater than in CABG patients.
• Patients undergoing valve surgery appear to
have similar immunologic response profiles
to CABG patients.
• In general, indices of inflammation appear to
correlate with overall severity of illness
rather than specific surgical procedure.
Extracorporeal Perfusion
Factors
•
•
•
•
•
•
•
Composition of the priming solution
Cardioplegia
Pulsatile or nonpulsatile perfusion
Type of oxygenator and pump
Type of extracorporeal circuit
Temperature during CPB
Large pressure changes across the CPB
circuit“shear stress
Transfusion
• Allogeneic Transfusion
• Autotransfusion
Postoperative Factors
• Continuous Renal Replacement Therapies
Continuous renal replacement therapies such as
hemofiltration appear to remove both
mediators, including TNF- and IL-1 , and
their inhibitors, such as TNFsr1, TNFsr2, and
IL-1ra, from the plasma of patients with SIRS.
• Mechanical Ventilation
patients with acute respiratory distress
syndrome, ventilation strategies that minimize
overdistention and recruitment–
derecruitment of the lung attenuate the
inflammatory response.
Strategies to Reduce
Endotoxemia
• Selective Digestive Decontamination
• Enteral Nutrition and Immunonutrition
• Optimization of intravascular volume
status
• Pharmacologic interventions to maximize
splanchnic perfusion
• The elective use of mechanical
circulatory support
Filtration Techniques
• Hemofiltration
• Leukocyte Depletion
Agents That May Suppress the
Inflammatory Response
• Serine Protease Inhibitors.
• Aprotinin.
• Pentoxifylline.
• Free Radical Scavengers and
Antioxidants.
Immunomodulation
• The Corticosteroid Controversy
• Cyclooxygenase Inhibitors
• Complement-directed Therapies
• Antimediator Therapies
• Therapies to Attenuate
Endothelial Injury
Conclusions
The goal of modulation of the perioperative
inflammatory response is to attenuate its
deleterious effects while preserving the ability of
the patient to mount an appropriate defense to the
physiologic trespasses of the perioperative period.
Although knowledge is growing about the role of
altered immune function, the role of
immunomodulatory therapies will remain
investigational (especially in view of the failures of
these therapies in recent sepsis trials) until the
initiating events in postoperative SIRS become
clearer.
The End.
2003
Eugene Yevstratov MD.