What question did this study set out to answer?

To determine the effects of varying arterial carbon dioxide tension on cerebral blood flow and the cerebral metabolic rate for oxygen during hypothermic cardiopulmonary bypass in humans.

August 1, 1990Stroke

Hypercarbia depresses cerebral oxygen consumption during cardiopulmonary bypass.

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Why the study?

Does higher PaCO2 management alter cerebral oxygen consumption and blood flow in patients undergoing hypothermic cardiopulmonary bypass?

Population

25 patients undergoing hypothermic (26-28 degrees C) cardiopulmonary bypass

Comparison

Management of PaCO2 at higher levels (49-72 mm Hg) vs Management of PaCO2 at lower levels (32-48 mm Hg)

Design

RCT, Randomly assigned to either of two methods of managing PaCO2

Follow-up

During cardiopulmonary bypass

Authors

DPD S ProughThe University of Texas Medical Branch at Galveston ARAnne T. RogersWestern University DSDavid A. StumpUnited States Air Force Academy

Discussion

Member takes

Implication

Higher PaCO2 may be considered in hypothermic CPB to lower cerebral oxygen demand; extends RCT evidence on cerebral physiology during bypass.

Key Points

To determine the effects of varying arterial carbon dioxide tension on cerebral blood flow and the cerebral metabolic rate for oxygen during hypothermic cardiopulmonary bypass in humans.
Randomized trial of 25 patients undergoing hypothermic (26–28 °C) cardiopulmonary bypass assigned to either uncorrected moderate PaCO2 (Group 1: 32–48 mm Hg, n=13) or high PaCO2 (Group 2: 49–72 mm Hg, n=12).
Cerebral blood flow was measured using xenon-133 clearance, and cerebral metabolic rate for oxygen was calculated from blood flow and cerebral arteriovenous oxygen content differences.
Cerebral metabolic rate for oxygen decreased significantly in Group 2 (0.31 ± 0.09 ml O2 · 100 g⁻¹ · min⁻¹ at PaCO2 55 ± 3 mm Hg; 0.21 ± 0.07 ml O2 · 100 g⁻¹ · min⁻¹ at PaCO2 68 ± 2 mm Hg) compared to Group 1 (0.40 ± 0.11 at 36 ± 2.0 mm Hg; 0.40 ± 0.14 at 45 ± 2 mm Hg; p < 0.05).
Cerebral blood flow increased across both groups in direct relation to increasing PaCO2 levels.

Structured PICO

Does higher PaCO2 management alter cerebral oxygen consumption and blood flow in patients undergoing hypothermic cardiopulmonary bypass?

Population

25 patients undergoing hypothermic (26-28 degrees C) cardiopulmonary bypass

Intervention

Management of PaCO2 at higher levels (49-72 mm Hg)

Comparator

Management of PaCO2 at lower levels (32-48 mm Hg)

Outcome

Cerebral metabolic rate for oxygen and cerebral blood flowsurrogate

Increasing PaCO2 during hypothermic cardiopulmonary bypass increases cerebral blood flow but depresses the cerebral metabolic rate for oxygen.

Cite This Study

Prough et al. (1990) studied this question.

synapsesocial.com/papers/6a918116252bb53f4e465b1f https://doi.org/10.1161/01.str.21.8.1162

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Implication

Higher PaCO2 may be considered in hypothermic CPB to lower cerebral oxygen demand; extends RCT evidence on cerebral physiology during bypass.

Hypercarbia depresses cerebral oxygen consumption during cardiopulmonary bypass.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Hypercarbia depresses cerebral oxygen consumption during cardiopulmonary bypass.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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