Transcript Acid-Base Abnormalities During Cardiopulmonary

Acid-Base Abnormalities
During
Cardiopulmonary
Resuscitation (CPR)
Anakapong Phunmanee M.D.
Associated Professor
Faculty of Medicine, Khon Kaen University
Cardiac Output During CPR
6
5
4
3
2
1
0
Normal CO
Normal CO = 2.5-3.6 L/m2(BSA)/min
CPR
Del Guercio LRM, et al. Circulation 1965; 32:I171-180.
Metabolism During CPR
Aerobic Metabolism
Anaerobic Metabolism
Progressive increase
CO2 in cells
PCO2 90-475 mmHg
PCO2 >475  EMD
MacGregor DC,et al. J Thorac Cardiovasc Surg 1974.
Confusion
Following CPR
Niemann JT,et al. Ann Emerg Med 1984.
Intamyocardial pH and cardiac venous blood
Planta M, et al. Circulation 1989;80:684-92.
CO2 transport during CPR
Planta M, et al. Circulation 1989;80:684-92.
Arterial pH and PCO2 different
Arterial vs Veneous blood during CPR
pH less acidotic
Arterial blood
Venous paradox
CO2
CO2
Vein
venous
blood
CO2
pH acidotic
pH 7.1
PvCO2 74
CO2
Weil MH,et al. N Eng J Med 1986; 314:153-156.
Myocardial K uptake during experimental CPR
Von Planta M, et al. Crit Care Med 1989;17:895-99.
Arterial blood during CPR
Severe Acidotic
arterial blood
Inadequate V/Q
Improved mechanical
technique
Hyperventilation
Correct intubation
Alternate method for circulation
Open-chest compression
Venoarterial bypass
Ornato JP, et al. Am J Emerg Med 1985;3:498-502.
Composition and physiochemical of buffer agents
Anorganic
NaHCO3
Na2CO3
Organic
THAM
NaHCO3 pH 8.0
Na2CO3 pH 11.7
THAM pH 8.4
(Tris-hydroxymethyl amino-methane)
Mixtures
CABICARB
CARBICARB pH 9.6
(NaHCO3, Na2CO3)
TRIBONATE
(NaHCO3, THAM, Phosphate, Acetate)
TRIBONATE pH 8.1
NaHCO3
H + HCO3 <-- -->H2CO3 <-- --> H2O2 +CO2
Na 1000 , Osm 2000 mOsm/l
Na2CO3
Na2CO3+ CO2 +H2O <----> 2HCO3 + 2Na
HCO3 + H
Na 1000 , Osm 1500 mOsm/l
CARBIBARB
NaHCO3 + Na2CO3
Na 1000 , Osm 1667 mOsm/l
Buffering agents and CPR
Myocardial pH
Kette F, et al. Clin Res 1988;36:10.
Comparison of coronary perfusion pressure
Shijie Sun Pharmacology and Experimental Therapneutics;1999:773-777.
NaHCO3 administration during
CPR: A Mistake
NaHCO3(PCO2 260-280)
CO2
Na
Na overload
HCO3
Hyperosmolarity
Falling Intracellular pH
CPR OUTCOME AFTER NaHCO3
DETRIMENT
BENEFIT
95%CI
Von Planta M. Circulatoire Aigue. 1994.
NaHCO3 administration during CPR


Should not be used until other proven
interventions (ET tube, defibrillation,
cardiac compression, adrenaline)
Estimated that this interventions required at
least 10 min.
Guideline for NaHCO3 administration
during CPR



Known preexisting metabolic acidosis with
or without hyperkalemia
Known hypercalcemia
Doasage
1 mEQ/kg then no more than half for
subsequent dose
 No more frequently than every 10 min


Postresuscitation phase, guideed by arterial
blood gas
Alternate buffer agents during CPR



THAM (tromethamine), potent amine buffer
DCA (Dichloroacetate), stimulating pyruvate
dehydrogenase (oxidative enzyme in step of
lactate to pyruvate)
However, no alternate buffer agents improve
survival during CPR
Lee WH, et al. Am Surg 1962.
Stacpoole PW, et al. N Engl J Med 1983.
Buffering agents and survival
Shijie Sun Pharmacology and Experimental Therapneutics;1999:773-777.
Capnography
Normal respiration, circulation, the PETCO2 about 4-5 % (1% approximately 7 mmHg)
Capnography
PETCO2 & Hyperventilation
PETCO2
Normal CO; PETCO2 ~ PCO2
Minute Ventilation
PETCO2 & Cardiac Output
PETCO2
ROSC Increase PETCO2
PETCO2 ¼ of normal
Cardiac Output
Common causes of low PETCO2
(< 2%)

Inadequate ventilation



V/Q mismatch


Pulmonary emboli
Inadequate blood flow





Esophageal intubation
Airway obstruction
Inadquate chest compression
Hypovolumia
Tension pneumothorax
Pericardial tamponade
Decrease metabolic production eq. hypothermia
End-tidal CO2 concentration
(PETCO2)

Clinical indication
Confirm ET tube placement (sen, spec, 100, 90%)
 Esophageal intubation results in PETCO2 < 0.5%
 Guide hemodynamic status: inadequate chest
compression PETCO2 < 1%
 Prognostic value: PETCO2 20 min after CPR < 10
mmHg accurately predicts death

Acid-Base Abnormalities During CPR:
Conclusion
Intracellular acidosis plays an important role
 The treatment is properly performed CPR
and airway management
Pharmacologic buffers have no benefit and
potentially risk

จบการบรรยาย
ขอขอบคุณทุกท่านที่ฟังการบรรยาย
ขอขอบคุณกรรมการหน่วยช่วยฟื้ นคืนชีพโรงพยาบาลศรี นคริ นทร์