Kazmaier, Stephan

[["dc.bibliographiccitation.firstpage","1470"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Journal of Cerebral Blood Flow & Metabolism"],["dc.bibliographiccitation.lastpage","1477"],["dc.bibliographiccitation.volume","35"],["dc.contributor.author","Grune, Frank F. G."],["dc.contributor.author","Kazmaier, Stephan"],["dc.contributor.author","Stolker, Robert Jan"],["dc.contributor.author","Visser, Gerhard H."],["dc.contributor.author","Weyland, Andreas"],["dc.date.accessioned","2018-11-07T09:52:39Z"],["dc.date.available","2018-11-07T09:52:39Z"],["dc.date.issued","2015"],["dc.description.abstract","In addition to cerebrovascular resistance (CVR) zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe) and the resistance area product (RAP) are supplemental determinants of cerebral blood flow (CBF). Until now, the interrelationship of PaCO2-induced changes in CBF, CVR, CPPe, ZFP, and RAP is not fully understood. In a controlled crossover trial, we investigated 10 anesthetized patients aiming at PaCO2 levels of 30, 37, 43, and 50 mm Hg. Cerebral blood flow was measured with a modified Kety-Schmidt-technique. Zero flow pressure and RAP was estimated by linear regression analysis of pressure-flow velocity relationships of the middle cerebral artery. Effective cerebral perfusion pressure was calculated as the difference between mean arterial pressure and ZFP, CVR as the ratio CPPe/CBF. Statistical analysis was performed by one-way RM-ANOVA. When comparing hypocapnia with hypercapnia, CBF showed a significant exponential reduction by 55% and mean V-MCA by 41%. Effective cerebral perfusion pressure linearly decreased by 17% while ZFP increased from 14 to 29 mm Hg. Cerebrovascular resistance increased by 96% and RAP by 39%; despite these concordant changes in mean CVR and Doppler-derived RAP correlation between these variables was weak (r = 0.43). In conclusion, under general anesthesia hypocapnia-induced reduction in CBF is caused by both an increase in CVR and a decrease in CPPe, as a consequence of an increase in ZFP."],["dc.identifier.doi","10.1038/jcbfm.2015.63"],["dc.identifier.isi","000360689500014"],["dc.identifier.pmid","25873428"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36175"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Nature Publishing Group"],["dc.relation.issn","1559-7016"],["dc.relation.issn","0271-678X"],["dc.title","Carbon dioxide induced changes in cerebral blood flow and flow velocity: role of cerebrovascular resistance and effective cerebral perfusion pressure"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","538"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","AINS - Anästhesiologie · Intensivmedizin · Notfallmedizin · Schmerztherapie"],["dc.bibliographiccitation.lastpage","544"],["dc.bibliographiccitation.volume","36"],["dc.contributor.author","Grune, Frank F. G."],["dc.contributor.author","Buhre, W."],["dc.contributor.author","Kazmaier, Stefan"],["dc.contributor.author","Weyland, Wolfgang"],["dc.contributor.author","Rieke, H."],["dc.contributor.author","Weyland, A."],["dc.date.accessioned","2018-11-07T08:39:46Z"],["dc.date.available","2018-11-07T08:39:46Z"],["dc.date.issued","2001"],["dc.description.abstract","Objective: This controlled study was designed to investigate 1.) the effects of 0,8% halothane and 2.) the effects of a variation in PaCO2 on the relationship between global cerebral blood flow (CBF) and middle cerebral artery flow velocity (CBFVMCA). Method: With ethical committee approval and informed patient consent we investigated 10 patients undergoing coronary artery bypass surgery. Measurements were performed under fentanyl/midazolam anaesthesia prior to the start of surgery. First, during a baseline period, ventilation was changed in a random sequence to achieve two different levels of arterial PCO2. (30 and 50 mmHg, respectively). Consequently, measurements were repeated during application of 0.8% halothane at identical PaCO2 levels. Measurements of global CBF were performed by the Kety-Schmidt-technique with argon as an indicator. Simultaneously, CBFVMCA was recorded by use of a 2-MHz transcranial Doppler system. Results: Application of 0.8% halothane caused a significant decrease in cerebrovascular resistance (CVR) both at hypocapnia and hypercapnia by 36 and 23%, respectively. Because of a concomitant reduction in cerebral perfusion pressure (CPP), however, CBF remained unchanged during application of halothane. The relationship between CBF and CBFVMCA was not altered when compared to the baseline period. Similarly, CO2 reactivity of CBF and CBFVMCA remained unchanged. CO2 reactivity of CBF significantly exceeded CO2 reactivity of CBFVMCA. Conclusion: The results of this clinical study demonstrate that Doppler-sonographic estimation of relative changes in CBF is not altered by application of 1 MAC halothane indicating that the decrease in CVR is not associated with a vasodilation of the proximal segments of basal cerebral arteries. The difference between CO2 reactivity of CBF and CBFVMCA, however, suggests that CO2-induced changes in CBF are slightly underestimated by TCD monitoring of CBFVMCA."],["dc.identifier.doi","10.1055/s-2001-17259"],["dc.identifier.isi","000171381700003"],["dc.identifier.pmid","11577352"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19075"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Georg Thieme Verlag Kg"],["dc.relation.issn","0939-2661"],["dc.title","The relationship between cerebral blood flow (CBF) and the cerebral blood flow velocity (CBFV): Influence of halothane and cerebral CO2 reactivity."],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","335"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Anesthesiology"],["dc.bibliographiccitation.lastpage","342"],["dc.bibliographiccitation.volume","120"],["dc.contributor.author","Grune, Frank F. G."],["dc.contributor.author","Kazmaier, Stephan"],["dc.contributor.author","Sonntag, Hans"],["dc.contributor.author","Stolker, Robert Jan"],["dc.contributor.author","Weyland, Andreas"],["dc.date.accessioned","2018-11-07T09:44:11Z"],["dc.date.available","2018-11-07T09:44:11Z"],["dc.date.issued","2014"],["dc.description.abstract","Background: Hyperventilation is known to decrease cerebral blood flow (CBF) and to impair cerebral metabolism, but the threshold in patients undergoing intravenous anesthesia is unknown. The authors hypothesized that reduced CBF associated with moderate hyperventilation might impair cerebral aerobic metabolism in patients undergoing intravenous anesthesia. Methods: Thirty male patients scheduled for coronary surgery were included in a prospective, controlled crossover trial. Measurements were performed under fentanyl-midazolam anesthesia in a randomized sequence aiming at partial pressures of carbon dioxide of 30 and 50 mmHg. Endpoints were CBF, blood flow velocity in the middle cerebral artery, and cerebral metabolic rates for oxygen, glucose, and lactate. Global CBF was measured using a modified Kety-Schmidt technique with argon as inert gas tracer. CBF velocity of the middle cerebral artery was recorded by transcranial Doppler sonography. Data were presented as mean (SD). Two-sided paired t tests and one-way ANOVA for repeated measures were used for statistical analysis. Results: Moderate hyperventilation significantly decreased CBF by 60%, blood flow velocity by 41%, cerebral oxygen delivery by 58%, and partial pressure of oxygen of the jugular venous bulb by 45%. Cerebral metabolic rates for oxygen and glucose remained unchanged; however, net cerebral lactate efflux significantly increased from -0.38 (2.18) to -2.41(2.43) mu mol min(-1) 100 g(-1). Conclusions: Moderate hyperventilation, when compared with moderate hypoventilation, in patients with cardiovascular disease undergoing intravenous anesthesia increased net cerebral lactate efflux and markedly reduced CBF and partial pressure of oxygen of the jugular venous bulb, suggesting partial impairment of cerebral aerobic metabolism at clinically relevant levels of hypocapnia."],["dc.identifier.doi","10.1097/ALN.0b013e3182a8eb09"],["dc.identifier.isi","000331559900012"],["dc.identifier.pmid","24008921"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34337"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Lippincott Williams & Wilkins"],["dc.relation.issn","1528-1175"],["dc.relation.issn","0003-3022"],["dc.title","Moderate Hyperventilation during Intravenous Anesthesia Increases Net Cerebral Lactate Efflux"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e1619"],["dc.bibliographiccitation.journal","PeerJ"],["dc.bibliographiccitation.volume","4"],["dc.contributor.author","Hinz, Jose"],["dc.contributor.author","Mansur, Ashham"],["dc.contributor.author","Hanekop, Gerd-Gunnar"],["dc.contributor.author","Weyland, Andreas"],["dc.contributor.author","Popov, Aron-Frederik"],["dc.contributor.author","Schmitto, Jan Dieter"],["dc.contributor.author","Grune, Frank F. G."],["dc.contributor.author","Bauer, Martin"],["dc.contributor.author","Kazmaier, Stephan"],["dc.date.accessioned","2018-11-07T10:19:11Z"],["dc.date.available","2018-11-07T10:19:11Z"],["dc.date.issued","2016"],["dc.description.abstract","The effects of isoflurane on the determinants of blood flow during Coronary Artery Bypass Graft (CABG) surgery are not completely understood. This study characterized the influence of isoflurane on the diastolic Pressure-Flow (P-F) relationship and Critical Occlusion Pressure (COP) during CABG surgery. Twenty patients undergoing CABG surgery were studied. Patients were assigned to an isoflurane or control group. Hemodynamic and flow measurements during CABG surgery were performed twice (15 minutes after the discontinuation of extracorporeal circulation (T15) and again 15 minutes later (T30)). The zero flow pressure intercept (a measure of COP) was extrapolated from a linear regression analysis of the instantaneous diastolic P-F relationship. In the isoflurane group, the application of isoflurane significantly increased the slope of the diastolic P-F relationship by 215% indicating a mean reduction of Coronary Vascular Resistance (CVR) by 46%. Simultaneously, the Mean Diastolic Aortic Pressure (MDAP) decreased by 19% mainly due to a decrease in the systemic vascular resistance index by 21%. The COP, cardiac index, heart rate, Left Ventricular End-Diastolic Pressure (LVEDP) and Coronary Sinus Pressure (CSP) did not change significantly. In the control group, the parameters remained unchanged. In both groups, COP significantly exceeded the CSP and LVEDP at both time points. We conclude that short-term application of isoflurane at a sedative concentration markedly increases the slope of the instantaneous diastolic P-F relationship during CABG surgery implying a distinct decrease with CVR in patients undergoing CABG surgery."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2016"],["dc.identifier.doi","10.7717/peerj.1619"],["dc.identifier.isi","000369406400004"],["dc.identifier.pmid","26966644"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/12920"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/41614"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Peerj Inc"],["dc.relation.issn","2167-8359"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Influence of isoflurane on the diastolic pressure-flow relationship and critical occlusion pressure during arterial CABG surgery: a randomized controlled trial"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e0171962"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Grune, Frank F. G."],["dc.contributor.author","Kazmaier, Stephan"],["dc.contributor.author","Hoeks, Sanne Elisabeth"],["dc.contributor.author","Stolker, Robert Jan"],["dc.contributor.author","Coburn, Marc"],["dc.contributor.author","Weyland, Andreas"],["dc.date.accessioned","2018-11-07T10:27:23Z"],["dc.date.available","2018-11-07T10:27:23Z"],["dc.date.issued","2017"],["dc.description.abstract","Objective Accumulating data have recently underlined argon As neuroprotective potential. However, to the best of our knowledge, no data are available on the cerebrovascular effects of argon (Ar) in humans. We hypothesized that argon inhalation does not affect mean blood flow velocity of the middle cerebral artery (Vmca), cerebral flow index (FI), zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe), resistance area product (RAP) and the arterio-jugular venous content differences of oxygen (AJVDO(2)), glucose (AJVDG), and lactate (AJVDL) in anesthetized patients. Materials and methods In a secondary analysis of an earlier controlled cross-over trial we compared parameters of the cerebral circulation under 15 minutes exposure to 70%Ar/30%O-2 versus 70%N-2/30%O-2 in 29 male patients under fentanyl-midazolam anaesthesia before coronary surgery. Vmca was measured by transcranial Doppler sonography. ZFP and RAP were estimated by linear regression analysis of pressure-flow velocity relationships of the middle cerebral artery. CPPe was calculated as the difference between mean arterial pressure and ZFP. AJVDO2, AJVDG and AJVDL were calculated as the differences in contents between arterial and jugular-venous blood of oxygen, glucose, and lactate. Statistical analysis was done by t-tests and ANOVA. Results Mechanical ventilation with 70% Ar did not cause any significant changes in mean arterial pressure, Vmca, FI, ZFP, CPPe, RAP, AJVDO2, AJVDG, and AJVDL. Discussion Short-term inhalation of 70% Ar does not affect global cerebral circulation or metabolism in male humans under general anaesthesia."],["dc.identifier.doi","10.1371/journal.pone.0171962"],["dc.identifier.isi","000394424500064"],["dc.identifier.pmid","28207907"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14323"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43223"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Argon does not affect cerebral circulation or metabolism in male humans"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]