Effects of hypotension and/or hypocapnia during sevoflurane anesthesia on perfusion and metabolites in the developing brain of piglets—a blinded randomized study

Ringer, Simone K; Ohlerth, Stefanie; Carrera, Inés; Mauch, Jacqueline; Spielmann, Nelly; Bettschart‐Wolfensberger, Regula; Weiß, Markus

doi:10.1111/pan.12956

Cited by 16 publications

(8 citation statements)

References 31 publications

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“…However, at least part of the effect could be attributed to hypocapnia, as no decrease in CBF was observed in a previous study using a similar animal model and investigating isolated hypotension . In contrast to the present results, a study using magnetic resonance imaging to detect changes in cerebral perfusion and metabolism in piglets reported that effects were more severe when hypocapnia and hypotension were combined . However, hypocapnia (2.7‐3.3 kPa) and hypotension (27‐33 mm Hg) goals were lower than those of the present trial.…”

Section: Discussioncontrasting

confidence: 99%

“…19 In contrast to the present results, a study using magnetic resonance imaging to detect changes in cerebral perfusion and metabolism in piglets reported that effects were more severe when hypocapnia and hypotension were combined. 26 and cerebrospinal fluid metabolites in adult dogs showed more severe changes in cerebral oxygenation compared to hypocapnia alone. 15 It is thus possible that the statistical power might have been insufficient to detect small differences between treatments in the present study.…”

Section: Discussionmentioning

confidence: 89%

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Effects of moderate and severe hypocapnia on intracerebral perfusion and brain tissue oxygenation in piglets

Ringer

Clausen

Spielmann

et al. 2019

Pediatric Anesthesia

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Background Hypocapnia is a common alteration during anesthesia in neonates. Aim To investigate the effects of hypocapnia and hypocapnia combined with hypotension (HCT) on cerebral perfusion and tissue oxygenation in anesthetized piglets. Method Thirty anesthetized piglets were randomly allocated to groups: moderate hypocapnia (mHC), severe hypocapnia (sHC), and HCT. Cerebral monitoring comprised a tissue oxygen partial pressure and a laser Doppler probe inserted into the brain tissue as well as a near‐infrared spectroscopy (NIRS) sensor placed on the skin, measuring regional oxygen saturation. Hypocapnia was induced by hyperventilation (target PaCO2 mHC: 3.7‐4; sHC: 3.1‐3.3 kPa) and hypotension by blood withdrawal and nitroprusside infusion (mean blood pressure: 35‐38 mm Hg). Data were analyzed at baseline, during (Tr20, Tr40, Tr60) and after (Post20, Post40, Post60) treatment. Results Compared to baseline, tissue oxygen partial pressure decreased significantly and equally during all treatments (mean [SD] at baseline: mHC 35.7 [32.45]; sHC: 28.1 [20.24]; HCT 25.4 [10.3] and at Tr60: mHC: 29.9 [27.36]; sHC: 22.2 [18.37]; HCT: 18.4 [9.5] mm Hg). Decreased laser Doppler flow was detected with all treatments at Tr20 (mHC: 0.9 [0.18]; sHC: 0.88 [0.15]; HCT: 0.97 [0.13] proportion from baseline). Independently of group, regional oxygen saturation varied only after reverting and not during treatment. Blood lactate, pH, HCO3−, and PaO2 increased during treatment with no differences between groups. Conclusion This animal model revealed reduced cerebral blood flow and brain tissue oxygenation during hypocapnia without detectable changes in regional oxygen saturation as measured by NIRS. Changes occurred as early as during moderate hypocapnia.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 89%

Effects of moderate and severe hypocapnia on intracerebral perfusion and brain tissue oxygenation in piglets

Ringer

Clausen

Spielmann

et al. 2019

Pediatric Anesthesia

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“…Coinciding with our results, using magnetic resonance imaging in an identical piglet model of hypotension, no changes in CBF could be detected despite signs of metabolic disturbances. 21 The observed increase in blood lactate during sHT in our study might have been a consequence of tissue hypoxia because of decreased capillary perfusion after arteriovenous shunting. 20 Despite a decrease in Pt O2 and possible tissue hypoxia during hypotension, no decrease in oxygen saturation was detected by NIRS.…”

Section: Discussionmentioning

confidence: 54%

Effects of moderate and severe arterial hypotension on intracerebral perfusion and brain tissue oxygenation in piglets

Ringer

Clausen

Spielmann

et al. 2018

British Journal of Anaesthesia

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Background: Hypotension is common in anaesthetised children, and its impact on cerebral oxygenation is unknown. The goal of the present study was to investigate the effects of moderate systemic arterial hypotension (mHT) and severe hypotension (sHT) on cerebral perfusion and brain tissue oxygenation in piglets. Methods: Twenty-seven anaesthetised piglets were randomly allocated to a control group, mHT group, or sHT group. Cerebral monitoring comprised a tissue oxygen partial pressure (Pt O2 ) and laser Doppler (LD) perfusion probe advanced into the brain tissue, and a near-infrared spectroscopy sensor placed over the skin measuring regional oxygen saturation (rSO 2 ). Arterial hypotension was induced by blood withdrawal and i.v. nitroprusside infusion [target MAP: 35e38 (mHT) and 27e30 (sHT) mm Hg]. Data were analysed at baseline, and every 20 min during and after treatment. Results: Compared with control, Pt O2 decreased equally with mHT and sHT [mean (SD) after 60 min: control: 17.1 (6.4); mHT: 6.4 (3.6); sHT: 7.2 (4.3) mm Hg]. No differences between groups were detected for rSO 2 and LD during treatment. However, in the sHT group, rSO 2 increased after restoring normotension [from 49.3 (9.5) to 58.9 (8.9)% Post60]. sHT was associated with an increase in blood lactate [from 1.5 (0.4) to 2.4 (0.9) mmol L À1 ], and a decrease in bicarbonate [28 (2.4) to 25.8 (2.6) mmol L À1 ] and base excess [4.7 (1.9) to 2.0 (2.7) mmol L À1 ] between baseline and 60 min after the start of the experiment. Conclusions: Induction of mHT and sHT by hypovolaemia and nitroprusside infusion caused alterations in brain tissue oxygenation in a piglet model, but without detectable changes in brain tissue perfusion and regional oxygen saturation.

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“…Maintaining normocapnia during mechanical ventilation of the lungs in children undergoing general anaesthesia is highly recommended in order to avoid peri‐operative central nervous system injury, particularly in younger patients and if combined with hypotension . The gold standard in anaesthesia and intensive care units is intermittent determination of PaCO 2 by arterial blood gas analysis combined with continuous monitoring of end‐tidal (ETCO 2 ) using capnography.…”

Section: Introductionmentioning

confidence: 99%

Arterial to end‐tidal carbon dioxide difference in children undergoing mechanical ventilation of the lungs during general anaesthesia

et al. 2017

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Capnography (ETCO ) is routinely used as a non-invasive estimate of arterial carbon dioxide (PaCO ) levels in order to modify ventilatory settings, whereby it is assumed that there is a positive gap between PaCO and ETCO of approximately 0.5 kPa. However, negative values (ETCO > PaCO ) can be observed. We retrospectively analysed arterial to end-tidal carbon dioxide differences in 799 children undergoing general anaesthesia with mechanical ventilation of the lungs in order to elucidate predictors for a negative gap. A total of 2452 blood gas analysis readings with complete vital sign monitoring, anaesthesia gas analysis and spirometry data were analysed. Mean arterial to end-tidal carbon dioxide difference was -0.18 kPa (limits of 95% agreement -1.10 to 0.74) and 71.2% of samples demonstrated negative values. The intercept model revealed PaCO to be the strongest predictor for a negative PaCO -ETCO difference. A decrease in PaCO by 1 kPa resulted in a decrease in the PaCO -ETCO difference by 0.23 kPa. This study demonstrates that ETCO monitoring in children whose lungs are mechanically ventilated may paradoxically lead to overestimation of ETCO (ETCO > PaCO ) with a subsequent risk of unrecognised hypocarbia.

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Effects of hypotension and/or hypocapnia during sevoflurane anesthesia on perfusion and metabolites in the developing brain of piglets—a blinded randomized study

Cited by 16 publications

References 31 publications

Effects of moderate and severe hypocapnia on intracerebral perfusion and brain tissue oxygenation in piglets

Effects of moderate and severe hypocapnia on intracerebral perfusion and brain tissue oxygenation in piglets

Effects of moderate and severe arterial hypotension on intracerebral perfusion and brain tissue oxygenation in piglets

Arterial to end‐tidal carbon dioxide difference in children undergoing mechanical ventilation of the lungs during general anaesthesia

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