Optimizing the intraoperative management of carbon dioxide concentration

Akça, Ozan

doi:10.1097/01.aco.0000192776.32398.5c

Cited by 50 publications

(26 citation statements)

References 55 publications

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“…In parallel with the increase in systemic blood flow regional myocardial perfusion of the right and left ventricle was markedly increased. This is in agreement with previous in vitro and in vivo data obtained during hypercapnia in coronary vessels [ 17 , 21 ] and reflects the elevated metabolic demands of the myocardial pump associated with the increase in heart rate and CO. In our animals without coronary artery disease perfusion of both subepicardial and subendocardial perfusion rose to a similar extent and the transmural distribution of myocardial blood flow was not altered by the ventilatory strategy.…”

Section: Discussionsupporting

confidence: 93%

Effects of lung protective mechanical ventilation associated with permissive respiratory acidosis on regional extra-pulmonary blood flow in experimental ARDS

2017

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BackgroundLung protective mechanical ventilation with limited peak inspiratory pressure has been shown to affect cardiac output in patients with ARDS. However, little is known about the impact of lung protective mechanical ventilation on regional perfusion, especially when associated with moderate permissive respiratory acidosis. We hypothesized that lung protective mechanical ventilation with limited peak inspiratory pressure and moderate respiratory acidosis results in an increased cardiac output but unequal distribution of blood flow to the different organs of pigs with oleic-acid induced ARDS.MethodsTwelve pigs were enrolled, 3 died during instrumentation and induction of lung injury. Thus, 9 animals received pressure controlled mechanical ventilation with a PEEP of 5 cmH2O and limited peak inspiratory pressure (17 ± 4 cmH2O) versus increased peak inspiratory pressure (23 ± 6 cmH2O) in a crossover-randomized design and were analyzed. The sequence of limited versus increased peak inspiratory pressure was randomized using sealed envelopes. Systemic and regional hemodynamics were determined by double indicator dilution technique and colored microspheres, respectively. The paired student t–test and the Wilcoxon test were used to compare normally and not normally distributed data, respectively.ResultsMechanical ventilation with limited inspiratory pressure resulted in moderate hypercapnia and respiratory acidosis (PaCO2 71 ± 12 vs. 46 ± 9 mmHg, and pH 7.27 ± 0.05 vs. 7.38 ± 0.04, p < 0.001, respectively), increased cardiac output (140 ± 32 vs. 110 ± 22 ml/min/kg, p<0.05) and regional blood flow in the myocardium, brain and spinal cord, adrenal and thyroid glands, the mucosal layers of the esophagus and jejunum, the muscularis layers of the esophagus and duodenum, and the gall and urinary bladders. Perfusion of kidneys, pancreas, spleen, hepatic arterial bed, and the mucosal and muscularis blood flow to the other evaluated intestinal regions remained unchanged.ConclusionsIn this porcine model of ARDS mechanical ventilation with limited peak inspiratory pressure resulting in moderate respiratory acidosis was associated with an increase in cardiac output. However, the better systemic blood flow was not uniformly directed to the different organs. This observation may be of clinical interest in patients, e.g. with cardiac, renal and cerebral pathologies.Electronic supplementary materialThe online version of this article (10.1186/s12871-017-0439-7) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 93%

Effects of lung protective mechanical ventilation associated with permissive respiratory acidosis on regional extra-pulmonary blood flow in experimental ARDS

2017

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“…12 Especially for the patients undergoing laparoscopic surgery, mild-to-moderate intraoperative hypercapnia is a well-tolerated but unintentional byproduct. 11 Eisele et al 13 suggested that hypercapnia decreased the MAC value of halothane in an earlier animal study, which was only observed in a very high Paco 2 level (above 95 mm Hg). However, our results showed that the MAC-BAR of sevoflurane significantly decreased in patients with slight hypercapnia of approximately 50 mm Hg of Paco 2 (40 mm Hg ≤ Etco 2 < 45 mm Hg).…”

Section: Discussionmentioning

confidence: 94%

“…In recent years, permissive hypercapnia (Pa co 2 >45 mm Hg) or tolerable hypocapnia (Pa co 2 <35 mm Hg) during mechanical ventilation remains prevalent in clinical practice, whether produced deliberately or accidentally. 11 However, in fact, different ranges of carbon dioxide tension (Pa co 2 ) vary in their physiological effects. 12 A previous study indicated that Pa co 2 decreased the MAC value of halothane in dogs at a high concentration, >95 mm Hg.…”

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confidence: 99%

Effects of Etco 2 on the Minimum Alveolar Concentration of Sevoflurane that Blunts the Adrenergic Response to Surgical Incision: A Prospective, Randomized, Double-Blinded Trial

Zhang

et al. 2021

Anesthesia &Amp; Analgesia

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BACKGROUND: CO 2 has anesthetic potency and effectively influences the circulatory system. We investigated the effects of Etco 2 on the minimum alveolar concentration of sevoflurane that blunts the adrenergic response to surgical incision (MAC-BAR) in patients undergoing radical surgery for gastric carcinoma. METHODS: Ninety patients undergoing radical gastric-carcinoma surgery under general anesthesia were enrolled and randomly assigned into 3 groups. After intubation, the Etco 2 in group L (n = 30), group N (n = 30), and group H (n = 30) was adjusted to 25 mm Hg ≤ Etco 2 <30 mm Hg, 30 mm Hg ≤ Etco 2 < 40 mm Hg, and 40 mm Hg ≤ Etco 2 < 45 mm Hg, respectively, by changes in controlled ventilation. Hemodynamics and depth of anesthesia were observed before and after skin incision. The MAC-BAR of sevoflurane for each group was determined using an up-and-down sequential-allocation technique.

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“…Hyperventilation lowers ICP and relaxes the brain [5]. These two phenomena are related: ICP is the ICP measured with the cranium closed and is determined by all of the contents of the cranium, whereas brain relaxation refers to the size and firmness of the brain in relation to the capacity of the bony cranium typically assessed by the surgeon during craniotomy [2].…”

Section: Physiological Effects Of Hyperventilation On Normal and Injumentioning

confidence: 99%

“…We use hyperventilation to decrease elevated intracranial pressure (ICP) [1] and relax a tense brain (i.e. to make it smaller and softer) [2,3] because hypocapnia leads to reduced cerebral blood flow (CBF) [4] and cerebral blood volume (CBV) [5]. Interestingly, this common practice is not based on robust evidence [6].…”

Section: Introductionmentioning

confidence: 99%

Hyperventilation in neurological patients

Zhang¹,

Guo²,

Wang

2019

Current Opinion in Anaesthesiology

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Purpose of reviewHyperventilation is commonly used in neurological patients to decrease elevated intracranial pressure (ICP) or relax a tense brain. However, the potentially deleterious effects of hyperventilation may limit its clinical application. The aim of this review is to summarize the physiological and outcome evidence related to hyperventilation in neurological patients.Recent findingsPhysiologically, hyperventilation may adversely decrease cerebral blood flow (CBF) and the match between the cerebral metabolic rate and CBF. In patients with severe traumatic brain injury (TBI), prolonged prophylactic hyperventilation with arterial carbon dioxide tension (PaCO2) less than 25 mmHg or during the first 24 h after injury is not recommended. Most patients (>90%) with an aneurysmal subarachnoid hemorrhage undergo hyperventilation (PaCO2 <35 mmHg); however, whether hyperventilation is associated with poor outcomes in this patient population is controversial. Hyperventilation is effective for brain relaxation during craniotomy; however, this practice is not based on robust outcome evidence.SummaryAlthough hyperventilation is commonly applied in patients with TBI or intracranial hemorrhage or in those undergoing craniotomy, its effects on patient outcomes have not been proven by quality research. Hyperventilation should be used as a temporary measure when treating elevated ICP or to relax a tense brain. Outcome research is needed to better guide the clinical use of hyperventilation in neurological patients.

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Optimizing the intraoperative management of carbon dioxide concentration

Abstract: Overall, the benefits of managing carbon dioxide concentration intraoperatively for the maintenance of cardiac output, tissue oxygenation, perfusion, intracranial pressure, and cerebrovascular reactivity are well defined.

Cited by 50 publications

References 55 publications

Effects of lung protective mechanical ventilation associated with permissive respiratory acidosis on regional extra-pulmonary blood flow in experimental ARDS

Effects of lung protective mechanical ventilation associated with permissive respiratory acidosis on regional extra-pulmonary blood flow in experimental ARDS

Effects of Etco 2 on the Minimum Alveolar Concentration of Sevoflurane that Blunts the Adrenergic Response to Surgical Incision: A Prospective, Randomized, Double-Blinded Trial

Hyperventilation in neurological patients

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