Effects Of Permissive Hypercapnia Research Articles

Progress on the Effects of Permissive Hypercapnia on the CNS During the Intraoperative Period: A Narrative Review.

Previous experimental findings and clinical evidence have shown the important role of carbon dioxide (CO2) in regulating cerebral vascular tension. CO2 can affect the CNS through various mechanisms. With factors such as patient physiology or surgical interventions potentially causing increased arterial partial pressure of carbon dioxide (PaCO2) levels during mechanical ventilation in general anesthesia, it is important to explore the potential risks or benefits of intraoperative permissive hypercapnia on brain function. In November 2023, we conducted a thorough review of PubMed to establish the article outline. Articles that were non-English or repetitive were eliminated. We collected information on the year, topic, key findings, and opinions of each article. This review not only comprehensively summarizes the factors that contribute to the elevation of intraoperative PaCO2, but also explores the impact of fluctuations in PaCO2 levels on the CNS and the underlying mechanisms involved. At the same time, this article provides our understanding of the potential clinical significance of actively regulating PaCO2 levels. In addition, we propose that the aspects of permissive hypercapnia can be further studied to provide a reliable basis for clinical decision-making. The effects of permissive hypercapnia on the CNS remain a topic of debate. Further prospective randomized controlled studies are needed to determine if permissive hypercapnia can be safely promoted during mechanical ventilation in general anesthesia.

Effects of permissive hypercapnia on intraoperative cerebral oxygenation and early postoperative cognitive function in older patients with non-acute fragile brain function undergoing laparoscopic colorectal surgery: protocol study

BackgroundPerioperative brain protection in older patients has been the focus of research recently; meanwhile, exploring the relationship between regional cerebral oxygen saturation (rSO2) and brain function in the perioperative period has been an emerging and challenging area—the difficulties related to the real-time monitoring of rSO2 and the choice of feasible interventions. As an advanced instrument for intraoperative rSO2 monitoring, the clinical application of near-infrared spectrum (NIRS) cerebral oxygen monitoring has gradually increased in popularity and is being recognized for its beneficial clinical outcomes in patients undergoing cardiac and noncardiac surgery. In addition, although sufficient evidence to support this hypothesis is still lacking, the effect of permissive hypercapnia (PHC) on rSO2 has expanded from basic research to clinical exploration. Therefore, monitoring intraoperative rSO2 in older patients with NIRS technology and exploring possible interventions that may change rSO2 and even improve postoperative cognitive performance is significant and clinically valuable.MethodsThis study is a single-center randomized controlled trial (RCT). 76 older patients are enrolled as subjects. Patients who meet the screening criteria will be randomly assigned 1:1 to the control and intervention groups. PHC-based mechanical ventilation will be regarded as an intervention. The primary outcome is the absolute change in the percent change in rSO2 from baseline to the completion of surgery in the intervention and control groups. Secondary outcomes mainly include observations of intraoperative cerebral oxygenation and metabolism, markers of brain injury, and assessments of patients' cognitive function using scale through postoperative follow-up.DiscussionThe findings of this RCT will reveal the effect of PHC on intraoperative rSO2 in older patients with nonacute fragile brain function (NFBF) and the approximate trends over time, and differences in postoperative cognitive function outcomes. We anticipate that the trial results will inform clinical policy decision-makers in clinical practice, enhance the management of intraoperative cerebral oxygen monitoring in older patients with comorbid NFBF, and provide guidance for clinical brain protection and improved postoperative cognitive function outcomes.Trial registrationChiCTR, ChiCTR2200062093, Registered 9/15/2022.

The Effect of Permissive Hypercapnia on Oxygenation and Post-operative Pulmonary Complication During One-lung Ventilation

The Effect of Permissive Hypercapnia on Oxygenation and Post-operative Pulmonary Complication During One-lung Ventilation

Effect of permissible hypercapnia on cognitive function after carotid endarterectomy

Objective To observe the effect of permissive hypercapnia(PH) on postoperative cognitive function in patients with carotid endarterectomy(CEA). Methods Forty patients who were selected for unilateral CEA were divided into two groups, aged 40-70 y, sex unlimited, American Society of Anesthesiologists(ASA) grade Ⅱ-Ⅲ. The patients were divided into two groups by random numerical table method: conventional ventilation group (group R) and PH group (group H). The parameters of mechanical ventilation in group R with hypercapnia ventilation were as follows: tidal volume (VT) was 8-10 ml/kg, respiratory rate (RR) was 12-16 bpm, arterial partial pressure of carbon dioxide (PaCO2) was 35-45 mmHg (1 mmHg=0.133 kPa), the parameters of mechanical ventilation in group H were set as follows: VT was 6-8 ml/kg, RR was 12-14 bpm, PaCO2 was 46-55 mmHg. The basic indexes such as operation time, carotid artery occlusion time, extubation time and post-anesthesia care unit (PACU) stay time were recorded. Cerebral oxygen saturation (rSO2) was monitored by near infrared spectroscopy (NIR). The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate, saturation of pulse oximetry (SpO2), end-tidal carbon dioxide partial pressure (PETCO2) and rSO2 were recorded before operation (T0), immediately after anesthesia induction (T1), 10 min after anesthesia induction(T2), immediately before carotid artery occlusion (T3), immediately after carotid artery occlusion (T4), and at the end of operation (T5). The cognitive function of the patients was evaluated by Mini-Mental State Examination (MMSE) scores at T0, 24 h, 48 h, 3 d and 7 d after operation. Results There were no significant difference in operation time, carotid artery occlusion time, extubation time and PACU residence time between the two groups(P>0.05). Compared with group R, PETCO2, rSO2 and MMSE score increased in group H at the time point of T2-T5, the MMSE score increased at 24 h, 48 h after operation, which alleviated the occurrence of postoperative cognitive dysfunction (POCD) in cognitive impairment after operation (P<0.05). Compared with T0, the rSO2 at T2-T5 time point in two groups was lower (P<0.05), MMSE scores decreased significantly at 24 h, 48 h, 3 d and 7 d after operation(P<0.05). Conclusions PH ventilation can improve cerebral oxygen metabolism and reduce the occurrence of POCD after operation. Key words: Hypercapnia; Carotid endarterectomy; Cognitive function; Brain oxygen

Effect of permissive hypercapnia on background cerebral electrical activity in premature babies.

Permissive hypercapnia is routinely practiced in neonatal intensive care units. The effect of permissive hypercapnia on the preterm brain and brain electrical activity is unknown. In this study, we aimed to determine the effect of chronic changes in partial pressure of blood carbon dioxide (PcO2) on brain electrical activity in preterm newborn babies born at or before 32 wk gestation. Eighty-three 1-h long digital electroencephalography (EEG) recordings were performed once a week for 4 wk on 25 babies with median gestational age of 29 wk (range: 23-32) after 48 h of age. Capillary blood gas measurements were performed midway through EEG recordings. There are associations between EEG parameters and blood pH, PcO2, and blood glucose concentration. However, there are also strong and complex associations with gestational age and substantial individual patient effects that make it difficult to demonstrate predictive associations. PcO2 and bicarbonate are significantly correlated with relative power of θ EEG band and Δ EEG band respectively after adjustment for age and intrababy correlations, but after allowing for multiple testing these relationships are of borderline statistical significance. Compensated respiratory acidosis may affect EEG by increased delta wave activity in preterm babies born before 32 wk gestation.

Permissive hypercapnia: From the ICU to the operating room

Although the effect of permissive hypercapnia on hemodynamics and right ventricular function was previously reported in patients with acute respiratory distress syndrome, the effects of acute controlled hypercapnia on right ventricular function during one-lung ventilation have not yet been investigated systematically. Experimental evidence is conflicting concerning the pulmonary vasodilatory or vasoconstrictive effect of hypercapnic acidosis. The final effect of hypercapnic acidosis on physiological functions depends on the level of hypercapnia and the context of the individual (healthy vs. diseased).

Tolerance to acute hypoxia maximally increases in case of joint effect of normobaric hypoxia and permissive hypercapnia in rats

IntroductionWe studied the comparative efficacy of independent and combined effects of normobaric hypoxia (90mmHg) and permissive hypercapnia (50mmHg) in increasing the tolerance of rats to acute hypobaric hypoxia. MethodsWe determined the time to loss of pose and life duration as a measure to assess the degree of tolerance of animals to hypobaric hypoxia by exposing them to an altitude of 11,500m (barometric=180mmHg). ResultsExposure to hypercapnic hypoxia increased the tolerance to acute hypobaric hypoxia compared to exposure to normobaric hypoxia or permissive hypercapnia alone. DiscussionThe positive effects of hypercapnia and hypercapnic hypoxia occurred after one exposure, and increasing the number of exposures proportionally increased the tolerance to acute hypobaric hypoxia. The effect of permissive hypercapnia on increasing the tolerance to acute hypobaric hypoxia was found to be significantly greater than that of exposure to normobaric hypoxia. Therefore, we propose that hypercapnia is the dominant factor in increasing tolerance to acute hypobaric hypoxia. ConclusionTolerance to acute hypoxia maximally increases in case of joint effect of normobaric hypoxia and permissive hypercapnia.

Pro/con debate: Should PaCO2 be tightly controlled in all patients with acute brain injuries?

You are the attending intensivist in a neurointensive care unit caring for a woman five days post-rupture of a cerebral aneurysm (World Federation of Neurological Surgeons Grade 4 and Fisher Grade 3). She is intubated for airway protection and mild hypoxemia related to an aspiration event at the time of aneurysm rupture, but is breathing spontaneously on the ventilator. Your patient is spontaneously hyperventilating with high tidal volumes despite minimal support and has developed significant hypocapnia. She has not yet developed the acute respiratory distress syndrome. You debate whether to tightly control her partial pressure of arterial carbon dioxide, weighing the known risks of acute hypocapnia in other forms of brain injury against the potential loss of clinical neuromonitoring associated with deep sedation and neuromuscular blockade in this patient who is at high risk of delayed ischemia from vasospasm. You are also aware of the potential implications of tidal volume control if this patient were to develop the acute respiratory distress syndrome and the effect of permissive hypercapnia on her intracranial pressure. In this paper we provide a detailed and balanced examination of the issues pertaining to this clinical scenario, including suggestions for clinical management of ventilation, sedation and neuromonitoring. Until more definitive clinical trial evidence is available to guide practice, clinicians are forced to carefully weigh the potential benefits of tight carbon dioxide control against the potential risks in each individual patient based on the clinical issues at hand.

Controvérsias acerca da acidose hipercápnica na síndrome do desconforto respiratório agudo

Acute respiratory distress syndrome is characterized by a diffuse inflammatory reaction of lung parenchyma induced by a direct insult to the alveolar epithelium (pulmonary acute respiratory distress syndrome) or an indirect lesion through the vascular endothelium (extrapulmonary acute respiratory distress syndrome). The main therapeutic strategy for acute respiratory distress syndrome is the ventilatory support. However, mechanical ventilation can worsen lung injury. In this context, a protective ventilatory strategy with low tidal volume has been proposed. The use of low tidal volume reduced the mortality rate of acute respiratory distress syndrome patients, but result in hypercapnic acidosis. The current article presents a review of literature on the effects of permissive hypercapnia in acute respiratory distress syndrome. To that end, we carried out a systematic review of scientific literature based on established criteria for documental analysis including clinical and experimental articles, using as data bases MedLine, LILACS, SciELO, PubMed, Cochrane. Hypercapnic acidosis has been considered by some authors as a modulator of the inflammatory process of acute respiratory distress syndrome. However, clinical and experimental studies on the effects of hypercapnic acidosis have shown controversial results. Therefore it is important to better elucidate the role of hypercapnic acidosis in acute respiratory distress syndrome.

Effects of permissive hypercapnia on brain edema induced by ischemia-reperfusion in rats

Objective To investigate the effects of permissive hypercapnia on brain edema induced by cerebral ischemia-reperfusion (I/R) .Methods Forty male Wistar rats weighing 300-350 g were randomly divided into 5 groups (n=8 each):group Ⅰ sham operation (S);groupⅡ cerebral I/R;group Ⅲ, Ⅳ,Ⅴ inhaled CO2for2 h to keep PaCO2 at 60-80 mm Hg (P1), 81-100 mm Hg (P2) and 101-120 mm Hg (P2) respectively, starting from the beginning of reperfusion. Cerebral I/R was produced by occlusion of bilateral common carotid arteries combined with controlled hypetension (MAP=30-40 mm Hg) for 15 min. The animals were killed at the end of 24 h reperfusion. Brains were immediately removed for determination of brain water content and expression of aquaporin4 (AQP-4) in hippocampus. Results The brain water content and AQP-4 protein expression in the hippocampus were significantly increased after 24 h reperfusion in group Ⅱ -Ⅴ as compared with control group (S),and were significantly higher in groupV (P3) than in group Ⅱ (I/R), Ⅲ (P1) and IV (P2). The AQP-4 expression was significantly lower in group Ⅲ and Ⅳ than in group Ⅴ. Conclusion Hypereapnia within the range of 60-100 mm Hg does not accentuate brain edema induced by cerebral I/R while hypercapnia at 101-120 mm Hg can aggravate brain edema and up-regulate AQP-4 protein expression in the brain. Key words: Hypercapnia; Reperfusion injury; Brain; Brain edema

Is ventilator-induced lung injury a promoter of multiple organ failure in adult respiratory distress syndrome? The effect of permissive hypercapnia on oxygenation and outcome.

Is ventilator-induced lung injury a promoter of multiple organ failure in adult respiratory distress syndrome? The effect of permissive hypercapnia on oxygenation and outcome.

Is ventilator-induced lung injury a promoter of multiple organ failure in adult respiratory distress syndrome? The effect of permissive hypercapnia on oxygenation and outcome

Is ventilator-induced lung injury a promoter of multiple organ failure in adult respiratory distress syndrome? The effect of permissive hypercapnia on oxygenation and outcome

Hemodynamics and alveolar-arterial PO2 differences at varying PaCO2 in anesthetized man.

Hemodynamics and alveolar-arterial PO2 differences at varying PaCO2 in anesthetized man.

Effect of pulmonary vasoconstriction on balance between alveolar ventilation and perfusion.

ArticleEffect of pulmonary vasoconstriction on balance between alveolar ventilation and perfusion.F Haas, and E H BergofskyF Haas, and E H BergofskyPublished Online:01 Apr 1968https://doi.org/10.1152/jappl.1968.24.4.491MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByRespiratory Sinus Arrhythmia and Entraining Heartbeats with Cheyne-Stokes Respiration: Cardiopulmonary Works to Be Minimal by Synchronizing Heartbeats with Breathing9 September 2016Inhalation Anesthesia Increases V/Q Regional Heterogeneity during Spontaneous Breathing in Healthy SubjectsAnesthesiology, Vol. 113, No. 6Effect of changes in ionized calcium concentration in arterial blood and metabolic acidosis on the arterial partial pressure of oxygen in dogsAmerican Journal of Veterinary Research, Vol. 67, No. 5Carbon dioxide added late in inspiration reduces ventilation-perfusion heterogeneity without causing respiratory acidosisThomas V. Brogan, H. Thomas Robertson, Wayne J. E. Lamm, Jennifer E. Souders, and Erik R. Swenson1 May 2004 | Journal of Applied Physiology, Vol. 96, No. 5Is ventilator-induced lung injury a promoter of multiple organ failure in adult respiratory distress syndrome? The effect of permissive hypercapnia on oxygenation and outcomeJournal of Anesthesia, Vol. 11, No. 1Respiratory Sinus ArrhythmiaCirculation, Vol. 94, No. 4Effect of tracheal gas insufflation on gas exchange in canine oleic acid-induced lung injuryCritical Care Medicine, Vol. 23, No. 2Elevated Pulmonary Artery Systolic Storage Volume Associated with Improved Ventilation-to-Perfusion Ratios in Acute Respiratory FailureChest, Vol. 102, No. 2Gas Exchange in Acid‐Base Disturbances1 January 2011Intrapulmonary shunting during deliberate hypotension with nifedipine, diltiazem and labetalol in dogsCanadian Anaesthetists’ Society Journal, Vol. 32, No. 2Right Ventricular Stroke-WorkChest, Vol. 84, No. 6Failure of acute hypoxia to alter pulmonary prostaglandin metabolism in dogsProstaglandins, Vol. 25, No. 5Effect of variations in blood hydrogen ion concentration on pulmonary gas exchange of artificially ventilated dogsPfl�gers Archiv European Journal of Physiology, Vol. 380, No. 1The role of carbon dioxide in the development of pulmonary insufficiencyThe Journal of Thoracic and Cardiovascular Surgery, Vol. 74, No. 1Mechanisms underlying vasomotor regulation of regional pulmonary blood flow in normal and disease statesThe American Journal of Medicine, Vol. 57, No. 3Ventilation-perfusion inequalities resulting from hypocapnic changes in lung mechanicsThe Journal of Thoracic and Cardiovascular Surgery, Vol. 63, No. 4Effects of acute through life-long hypoxic exposure on exercise pulmonary gas exchangeRespiration Physiology, Vol. 13, No. 1QUALITY AND SIGNIFICANCE OF PULMONAIRY ADAPTATIONS TO WORK IN ADOLESCENT ALTITUDE RESIDENTSActa Paediatrica, Vol. 60, No. s217Cardiorespiratory effects of intravenous isoprenaline and salbutamol in dogs19 July 2012 | British Journal of Pharmacology, Vol. 41, No. 3 More from this issue > Volume 24Issue 4April 1968Pages 491-7 https://doi.org/10.1152/jappl.1968.24.4.491PubMed5643396History Published online 1 April 1968 Published in print 1 April 1968 Metrics