1
|
Dynamic cerebral autoregulation during step-wise increases in blood pressure during anaesthesia: A nonrandomised interventional trial. Eur J Anaesthesiol 2023; 40:407-417. [PMID: 36655712 PMCID: PMC10155696 DOI: 10.1097/eja.0000000000001798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Classically, cerebral autoregulation (CA) entails cerebral blood flow (CBF) remaining constant by cerebrovascular tone adapting to fluctuations in mean arterial pressure (MAP) between ∼60 and ∼150 mmHg. However, this is not an on-off mechanism; previous work has suggested that vasomotor tone is proportionally related to CA function. During propofol-based anaesthesia, there is cerebrovascular vasoconstriction, and static CA remains intact. Sevoflurane-based anaesthesia induces cerebral vasodilation and attenuates CA dose-dependently. It is unclear how this translates to dynamic CA across a range of blood pressures in the autoregulatory range. OBJECTIVE The aim of this study was to quantify the effect of step-wise increases in MAP between 60 and 100 mmHg, using phenylephrine, on dynamic CA during propofol- and sevoflurane-based anaesthesia. DESIGN A nonrandomised interventional trial. SETTING Single centre enrolment started on 11 January 2019 and ended on 23 September 2019. PATIENTS We studied American Society of Anesthesiologists (ASA) I/II patients undergoing noncardiothoracic, nonneurosurgical and nonlaparoscopic surgery under general anaesthesia. INTERVENTION In this study, cerebrovascular tone was manipulated in the autoregulatory range by increasing MAP step-wise using phenylephrine in patients receiving either propofol- or sevoflurane-based anaesthesia. MAP and mean middle cerebral artery blood velocity (MCA Vmean ) were measured in ASA I and II patients, anaesthetised with either propofol ( n = 26) or sevoflurane ( n = 28), during 10 mmHg step-wise increments of MAP between 60 and 100 mmHg. Static CA was determined by plotting 2-min averaged MCA Vmean versus MAP. Dynamic CA was determined using transfer function analysis and expressed as the phase lead (°) between MAP and MCA Vmean oscillations, created with positive pressure ventilation with a frequency of 6 min -1 . MAIN OUTCOMES The primary outcome of this study was the response of dynamic CA during step-wise increases in MAP during propofol- and sevoflurane-based anaesthesia. RESULTS MAP levels achieved per step-wise increments were comparable between anaesthesia regiment (63 ± 3, 72 ± 2, 80 ± 2, 90 ± 2, 100 ± 3 mmHg, and 61 ± 4, 71 ± 2, 80 ± 2, 89 ± 2, 98 ± 4 mmHg for propofol and sevoflurane, respectively). MCA Vmean increased more during step-wise MAP increments for sevoflurane compared to propofol ( P ≤0.001). Dynamic CA improved during propofol (0.73° mmHg -1 , 95% CI 0.51 to 0.95; P ≤ 0.001)) and less pronounced during sevoflurane-based anaesthesia (0.21° mmHg -1 (95% CI 0.01 to 0.42, P = 0.04). CONCLUSIONS During general anaesthesia, dynamic CA is dependent on MAP, also within the autoregulatory range. This phenomenon was more pronounced during propofol anaesthesia than during sevoflurane. TRIAL REGISTRATION NCT03816072 ( https://clinicaltrials.gov/ct2/show/NCT03816072 ).
Collapse
|
2
|
Exploring metrics for the characterization of the cerebral autoregulation during head-up tilt and propofol general anesthesia. Auton Neurosci 2022; 242:103011. [PMID: 35834916 DOI: 10.1016/j.autneu.2022.103011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 05/30/2022] [Accepted: 07/03/2022] [Indexed: 11/22/2022]
Abstract
Techniques grounded on the simultaneous utilization of Tiecks' second order differential equations and spontaneous variability of mean arterial pressure (MAP) and mean cerebral blood flow velocity (MCBFV), recorded from middle cerebral arteries through a transcranial Doppler device, provide a characterization of cerebral autoregulation (CA) via the autoregulation index (ARI). These methods exploit two metrics for comparing the measured MCBFV series with the version predicted by Tiecks' model: normalized mean square prediction error (NMSPE) and normalized correlation ρ. The aim of this study is to assess the two metrics for ARI computation in 13 healthy subjects (age: 27 ± 8 yrs., 5 males) at rest in supine position (REST) and during 60° head-up tilt (HUT) and in 19 patients (age: 64 ± 8 yrs., all males), scheduled for coronary artery bypass grafting, before (PRE) and after (POST) propofol general anesthesia induction. Analyses were carried out over the original MAP and MCBFV pairs and surrogate unmatched couples built individually via time-shifting procedure. We found that: i) NMSPE and ρ metrics exhibited similar performances in passing individual surrogate test; ii) the two metrics could lead to different ARI estimates; iii) CA was not different during HUT or POST compared to baseline and this conclusion held regardless of the technique and metric for ARI estimation. Results suggest a limited impact of the sympathetic control on CA.
Collapse
|
3
|
Meyer M, Juenemann M, Braun T, Schirotzek I, Tanislav C, Engelhard K, Schramm P. Impaired Cerebrovascular Autoregulation in Large Vessel Occlusive Stroke after Successful Mechanical Thrombectomy: A Prospective Cohort Study. J Stroke Cerebrovasc Dis 2020; 29:104596. [PMID: 31902644 DOI: 10.1016/j.jstrokecerebrovasdis.2019.104596] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/27/2019] [Accepted: 12/05/2019] [Indexed: 01/14/2023] Open
Abstract
INTRODUCTION Successful thrombectomy improves morbidity and mortality after stroke. The present prospective, observational cohort study investigated a potential correlation between the successful restoration of tissue perfusion by mechanical thrombectomy and intact cerebrovascular autoregulation (CA). OBJECTIVE Status of CA in patients with large vessel occlusive stroke after thrombectomy. METHODS After thrombectomy CA was measured using transcranial Doppler ultrasound. For this purpose a moving correlation index (Mxa) based on spontaneous arterial blood pressure fluctuations and corresponding cerebral blood flow velocity changes was calculated. CA impairment was defined by Mxa values more than .3. RESULTS Twenty patients with an acute occlusion of the middle cerebral artery or distal internal carotid artery were included. A successful recanalization of the occluded vessel via interventional thrombectomy was achieved in 10 of these patients (successful recanalization group), while in 10 patients mechanical recanalization failed or could not be applied (no recanalization group). Mean Mxa at stroke side was .58 ± .21 Table 2a in patients with successful intervention. At the unaffected hemisphere Mxa was .50 ± .20 Table 2a in successful recanalization group and .45 ± .24 Table 2b in no recanalization group without statistically significant differences. Based on the previously defined Mxa cut off more than .3, CA impairment was observable in all successful recanalized patients and in 8 of 10 patients with unsuccessful interventional treatment. CONCLUSIONS These results suggest that brain perfusion may be affected due to impaired CA even after successful mechanical thrombectomy. Therefore, a tight blood pressure management is of great importance in post-thrombectomy stroke treatment to avoid cerebral hypo- and hyperperfusion.
Collapse
Affiliation(s)
- Marco Meyer
- Department of Geriatrics, Jung-Stilling Hospital Siegen, Siegen, Germany.
| | - Martin Juenemann
- Department of Neurology, University hospital Giessen and Marburg location Giessen, Giessen, Germany
| | - Tobias Braun
- Department of Neurology, University hospital Giessen and Marburg location Giessen, Giessen, Germany
| | - Ingo Schirotzek
- Department of Neurology, University hospital Giessen and Marburg location Giessen, Giessen, Germany
| | - Christian Tanislav
- Department of Geriatrics, Jung-Stilling Hospital Siegen, Siegen, Germany
| | - Kristin Engelhard
- Department of Anesthesiology, Johannes Gutenberg-University, University medical hospital Mainz, Mainz, Germany
| | - Patrick Schramm
- Department of Anesthesiology, Johannes Gutenberg-University, University medical hospital Mainz, Mainz, Germany
| |
Collapse
|
4
|
Internal Carotid Artery Blood Flow Response to Anesthesia, Pneumoperitoneum, and Head-up Tilt during Laparoscopic Cholecystectomy. Anesthesiology 2019; 131:512-520. [DOI: 10.1097/aln.0000000000002838] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Abstract
Editor’s Perspective
What We Already Know about This Topic
What This Article Tells Us That Is New
Background
Little is known about how implementation of pneumoperitoneum and head-up tilt position contributes to general anesthesia-induced decrease in cerebral blood flow in humans. We investigated this question in patients undergoing laparoscopic cholecystectomy, hypothesizing that cardiorespiratory changes during this procedure would reduce cerebral perfusion.
Methods
In a nonrandomized, observational study of 16 patients (American Society of Anesthesiologists physical status I or II) undergoing laparoscopic cholecystectomy, internal carotid artery blood velocity was measured by Doppler ultrasound at four time points: awake, after anesthesia induction, after induction of pneumoperitoneum, and after head-up tilt. Vessel diameter was obtained each time, and internal carotid artery blood flow, the main outcome variable, was calculated. The authors recorded pulse contour estimated mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV) index, cardiac index, end-tidal carbon dioxide (ETco2), bispectral index, and ventilator settings. Results are medians (95% CI).
Results
Internal carotid artery blood flow decreased upon anesthesia induction from 350 ml/min (273 to 410) to 213 ml/min (175 to 249; −37%, P < 0.001), and tended to decrease further with pneumoperitoneum (178 ml/min [127 to 208], −15%, P = 0.026). Tilt induced no further change (171 ml/min [134 to 205]). ETco2 and bispectral index were unchanged after induction. MAP decreased with anesthesia, from 102 (91 to 108) to 72 (65 to 76) mmHg, and then remained unchanged (Pneumoperitoneum: 70 [63 to 75]; Tilt: 74 [66 to 78]). Cardiac index decreased with anesthesia and with pneumoperitoneum (overall from 3.2 [2.7 to 3.5] to 2.3 [1.9 to 2.5] l · min−1 · m−2); tilt induced no further change (2.1 [1.8 to 2.3]). Multiple regression analysis attributed the fall in internal carotid artery blood flow to reduced cardiac index (both HR and SV index contributing) and MAP (P < 0.001). Vessel diameter also declined (P < 0.01).
Conclusions
During laparoscopic cholecystectomy, internal carotid artery blood flow declined with anesthesia and with pneumoperitoneum, in close association with reductions in cardiac index and MAP. Head-up tilt caused no further reduction. Cardiac output independently affects human cerebral blood flow.
Collapse
|
5
|
Schwarz M, Rivera G, Hammond M, Silman Z, Jackson K, Kofke WA. Acousto-Optic Cerebral Blood Flow Monitoring During Induction of Anesthesia in Humans. Neurocrit Care 2017; 24:436-41. [PMID: 26399247 DOI: 10.1007/s12028-015-0201-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Past transcranial Doppler (TCD) studies have documented the effects of the sequence of anesthesia induction followed by intubation on cerebral blood flow (CBF) velocity. The purpose of this study was to determine whether acousto-optic CBF monitoring would detect changes in CBF which are known to occur with propofol and subsequent endotracheal intubation. METHODS Seventy-two patients scheduled for elective non-intracranial surgery were evaluated. A Cerox 3215F (Ornim Medical) acousto-optic CBF monitor was used. The acousto-optic transducers were applied bifrontally prior to induction. Baseline cerebral flow index (CFI) values were obtained for at least 2 min prior to induction, set to a unitless value of 100. Subsequent relative changes in CFI from baseline were determined at the lowest value over 3 min after propofol injection but before laryngoscopy; and the highest value over 5 min after the start of laryngoscopy. CFI data were evaluated using Friedman's test. RESULTS The median dose of propofol [interquartile range] given was 200 mg [160-250]. CFI decreased to 84 % of baseline after propofol and increased to 147 % of baseline after endotracheal intubation (both p < 0.001); MAP decreased after intravenous induction of anesthesia from 103 ± 15 to 86 ± 15 mmHg (p < 0.001) and then returned following endotracheal intubation to 104 ± 20 mmHg. CONCLUSIONS Our data are congruent with previous observations made with TCD under similar experimental conditions. Such observations support the notion that acousto-optic monitoring yields valid real-time measures of changes in CBF in humans. Further validation against other quantitative measures of CBF would be appropriate.
Collapse
Affiliation(s)
- Marlon Schwarz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA
| | - Giovanni Rivera
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA
| | - Mary Hammond
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA
| | - Zmira Silman
- Ornim Medical Ltd, 15 Atir Yeda St., Kfar Saba, Israel, 4464312
| | - Kirk Jackson
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA
| | - W Andrew Kofke
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, USA. .,Department of Neurosurgery, University of Pennsylvania, 7 Dulles Building, 3400 Spruce St, Philadelphia, PA, 19104-4283, USA.
| |
Collapse
|
6
|
Mikkelsen MLG, Ambrus R, Rasmussen R, Miles JE, Poulsen HH, Moltke FB, Eriksen T. The effect of dexmedetomidine on cerebral perfusion and oxygenation in healthy piglets with normal and lowered blood pressure anaesthetized with propofol-remifentanil total intravenous anaesthesia. Acta Vet Scand 2017; 59:27. [PMID: 28468670 PMCID: PMC5415812 DOI: 10.1186/s13028-017-0293-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 04/21/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND During anaesthesia and surgery, in particular neurosurgery, preservation of cerebral perfusion and oxygenation (CPO) is essential for normal postoperative brain function. The isolated effects on CPO of either individual anaesthetic drugs or entire anaesthetic protocols are of importance in both clinical and research settings. Total intravenous anaesthesia (TIVA) with propofol and remifentanil is widely used in human neuroanaesthesia. In addition, dexmedetomidine is receiving increasing attention as an anaesthetic adjuvant in neurosurgical, intensive care, and paediatric patients. Despite the extensive use of pigs as animal models in neuroscience and the increasing use of both propofol-remifentanil and dexmedetomidine, very little is known about their combined effect on CPO in pigs with uninjured brains. This study investigates the effect of dexmedetomidine on CPO in piglets with normal and lowered blood pressure during background anaesthesia with propofol-remifentanil TIVA. Sixteen healthy female Danish pigs (crossbreeds of Danish Landrace, Yorkshire and Duroc, 25-34 kg) were used. Three animals were subsequently excluded. The animals were randomly allocated into one of two groups with either normal blood pressure (NBP, n = 6) or with induced low blood pressure (LBP, n = 7). Both groups were subjected to the same experimental protocol. Intravenous propofol induction was performed without premedication. Anaesthesia was maintained with propofol-remifentanil TIVA, and later supplemented with continuous infusion of dexmedetomidine. Assessments of cerebral perfusion obtained by laser speckle contrast imaging (LSCI) were related to cerebral oxygenation measures (PbrO2) obtained by an intracerebral Clark-type Licox probe. RESULTS Addition of dexmedetomidine resulted in a 32% reduction in median PbrO2 values for the LBP group (P = 0.03), but no significant changes in PbrO2 were observed for the NBP group. No significant changes in LSCI readings were observed in either group between any time points, despite a 28% decrease in the LBP group following dexmedetomidine administration. Caval block resulted in a significant (P = 0.02) reduction in median MAP from 68 mmHg (range 63-85) at PCB to 58 mmHg (range 53-63) in the LBP group, but no significant differences in either PbrO2 or LSCI were observed due to this intervention (P = 0.6 and P = 0.3 respectively). CONCLUSIONS Addition of dexmedetomidine to propofol-remifentanil TIVA resulted in a significant decrease in cerebral oxygenation (PbrO2) measurements in piglets with lowered blood pressure. Cerebral perfusion (LSCI) did not decrease significantly in this group. In piglets with normal blood pressure, no significant changes in cerebral perfusion or oxygenation were seen in response to addition of dexmedetomidine to the background anaesthesia.
Collapse
Affiliation(s)
- Mai Louise Grandsgaard Mikkelsen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Rikard Ambrus
- Department of Surgical Gastroenterology C, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
| | - Rune Rasmussen
- Department of Neurosurgery, The Neuroscience Centre, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
| | - James Edward Miles
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Helle Harding Poulsen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Finn Borgbjerg Moltke
- Department of Neuroanaesthesia, Rigshospitalet, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
- Department of Anaesthesia, Bispebjerg and Frederiksberg Hospitals, Faculty of Health and Medical Sciences, University of Copenhagen, 23 Bispebjerg Bakke, 2400 Copenhagen NV, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| |
Collapse
|
7
|
Abstract
This article provides a review of cerebral autoregulation, particularly as it relates to the clinician scientist experienced in neuroscience in anesthesia and critical care. Topics covered are biological mechanisms; methods used for assessment of autoregulation; effects of anesthetics; role in control of cerebral hemodynamics in health and disease; and emerging areas, such as role of age and sex in contribution to dysautoregulation. Emphasis is placed on bidirectional translational research wherein the clinical informs the study design of basic science studies, which, in turn, informs the clinical to result in development of improved therapies for treatment of central nervous system conditions.
Collapse
Affiliation(s)
- William M Armstead
- Department of Anesthesiology and Critical Care, University of Pennsylvania, 3620 Hamilton Walk, JM3, Philadelphia, PA l9l04, USA; Department of Pharmacology, University of Pennsylvania, Philadelphia, PA l9l04, USA.
| |
Collapse
|
8
|
Mikkelsen MLG, Ambrus R, Miles JE, Poulsen HH, Moltke FB, Eriksen T. Effect of propofol and remifentanil on cerebral perfusion and oxygenation in pigs: a systematic review. Acta Vet Scand 2016; 58:42. [PMID: 27334375 PMCID: PMC4917978 DOI: 10.1186/s13028-016-0223-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/13/2016] [Indexed: 12/09/2022] Open
Abstract
The objective of this review is to evaluate the existing literature with regard to the influence of propofol and remifentanil total intravenous anaesthesia (TIVA) on cerebral perfusion and oxygenation in healthy pigs. Anaesthesia has influence on cerebral haemodynamics and it is important not only in human but also in veterinary anaesthesia to preserve optimal regulation of cerebral haemodynamics. Propofol and remifentanil are widely used in neuroanaesthesia and are increasingly used in experimental animal studies. In translational models, the pig has advantages compared to small laboratory animals because of brain anatomy, metabolism, neurophysiological maturation, and cerebral haemodynamics. However, reported effects of propofol and remifentanil on cerebral perfusion and oxygenation in pigs have not been reviewed. An electronic search identified 99 articles in English. Title and abstract screening selected 29 articles for full-text evaluation of which 19 were excluded with reasons. Of the 10 peer-reviewed articles included for review, only three had propofol or remifentanil anaesthesia as the primary study objective and only two directly investigated the effect of anaesthesia on cerebral perfusion and oxygenation (CPO). The evidence evaluated in this systematic review is limited, not focused on propofol and remifentanil and possibly influenced by factors of potential importance for CPO assessment. In one study of healthy pigs, CPO measures were within normal ranges following propofol-remifentanil anaesthesia, and addition of a single remifentanil bolus did not affect regional cerebral oxygen saturation (rSO2). Even though the pool of evidence suggests that propofol and remifentanil alone or in combination have limited effects on CPO in healthy pigs, confirmative evidence is lacking.
Collapse
Affiliation(s)
| | - Rikard Ambrus
- Department of Surgical Gastroenterology C, Rigshospitalet, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
| | - James Edward Miles
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Helle Harding Poulsen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| | - Finn Borgbjerg Moltke
- Department of Neuroanaesthesia, Rigshospitalet, University of Copenhagen, 9 Blegdamsvej, 2100 Copenhagen Ø, Denmark
- Department of Anaesthesia, Sealand Hospital, University of Copenhagen, 1 Lykkebækvej, 4600 Køge, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 16 Dyrlægevej, 1870 Frederiksberg C, Denmark
| |
Collapse
|
9
|
Postoperative care of the surgical patient with neurological disease. Int Anesthesiol Clin 2015; 53:166-76. [PMID: 25551748 DOI: 10.1097/aia.0000000000000039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
10
|
Fontana J, Wenz H, Schmieder K, Barth M. Impairment of Dynamic Pressure Autoregulation Precedes Clinical Deterioration after Aneurysmal Subarachnoid Hemorrhage. J Neuroimaging 2015; 26:339-45. [DOI: 10.1111/jon.12295] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/03/2015] [Accepted: 08/06/2015] [Indexed: 11/30/2022] Open
Affiliation(s)
- Johann Fontana
- Department of Neurosurgery; Ruhr-University Bochum; Bochum Germany
| | - Holger Wenz
- Department of Neuroradiology; University Medicine Mannheim, Medical Faculty Mannheim of the University of Heidelberg; Germany
| | | | - Martin Barth
- Department of Neurosurgery; Ruhr-University Bochum; Bochum Germany
| |
Collapse
|
11
|
Ševerdija EE, Vranken NPA, Simons AP, Gommer ED, Heijmans JH, Maessen JG, Weerwind PW. Hemodilution Combined With Hypercapnia Impairs Cerebral Autoregulation During Normothermic Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2015; 29:1194-9. [PMID: 26146135 DOI: 10.1053/j.jvca.2015.03.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the influence of hemodilution and arterial pCO2 on cerebral autoregulation and cerebral vascular CO2 reactivity. DESIGN Prospective interventional study. SETTING University hospital-based single-center study. PARTICIPANTS Forty adult patients undergoing elective cardiac surgery using normothermic cardiopulmonary bypass. INTERVENTIONS Blood pressure variations induced by 6/minute metronome-triggered breathing (baseline) and cyclic 6/min changes of indexed pump flow at 3 levels of arterial pCO2. MEASUREMENTS AND MAIN RESULTS Based on median hematocrit on bypass, patients were assigned to either a group of a hematocrit ≥28% or<28%. The autoregulation index was calculated from cerebral blood flow velocity and mean arterial blood pressure using transfer function analysis. Cerebral vascular CO2 reactivity was calculated using cerebral tissue oximetry data. Cerebral autoregulation as reflected by autoregulation index (baseline 7.5) was significantly affected by arterial pCO2 (median autoregulation index amounted to 5.7, 4.8, and 2.8 for arterial pCO2 of 4.0, 5.3, and 6.6 kPa, p≤0.002) respectively. Hemodilution resulted in a decreased autoregulation index; however, during hypocapnia and normocapnia, there were no significant differences between the two hematocrit groups. Moreover, the autoregulation index was lowest during hypercapnia when hematocrit was<28% (autoregulation index 3.3 versus 2.6 for hematocrit ≥28% and<28%, respectively, p = 0.014). Cerebral vascular CO2 reactivity during hypocapnia was significantly lower when perioperative hematocrit was<28% (p = 0.018). CONCLUSIONS Hemodilution down to a hematocrit of<28% combined with hypercapnia negatively affects dynamic cerebral autoregulation, which underlines the importance of tight control of both hematocrit and paCO2 during CPB.
Collapse
Affiliation(s)
| | | | | | | | - John H Heijmans
- Anesthesiology, Maastricht University Medical Center, AZ Maastricht, The Netherlands
| | | | | |
Collapse
|
12
|
Dynamic Autoregulatory Response After Aneurysmal Subarachnoid Hemorrhage and Its Relation to Angiographic Vasospasm and Clinical Outcome. Neurocrit Care 2015; 23:355-63. [DOI: 10.1007/s12028-014-0104-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
13
|
Silva A, Venâncio C, Ortiz AL, Souza AP, Amorim P, Ferreira DA. The effect of high doses of remifentanil in brain near-infrared spectroscopy and in electroencephalographic parameters in pigs. Vet Anaesth Analg 2013; 41:153-62. [PMID: 24119044 DOI: 10.1111/vaa.12091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 03/20/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To study the effects of a high remifentanil bolus dose on pig's electroencephalographic indices and on brain regional and global oxygenation. STUDY DESIGN Prospective experimental study. ANIMALS Twelve healthy Large-White male pigs, age 3 months and weight 26.2 ± 3.6 kg. METHODS Anaesthesia was induced with intravenous propofol 4 mg kg⁻¹, then maintained with constant rate infusions of propofol (15 mg kg⁻¹ hour⁻¹) and remifentanil (0.3 μg kg⁻¹ minute⁻¹). Following instrumentation, all pigs received a 5 μg kg⁻¹ remifentanil bolus. The responses of jugular venous oxygen saturation, cardiac output and cerebral oxygen saturation to the remifentanil bolus were studied. The Bispectral index, spectral edge frequency 95%, total power, approximate entropy and permutation entropy were also studied. Repeated measures anova and Pearson correlation were used to analyze the effect of remifentanil bolus on these variables until 5 minutes after the bolus. RESULTS Cardiac output and cerebral oxygen saturation decreased significantly after the remifentanil bolus from 4.6 ± 0.9 to 3.8 ± 1.0 L minute⁻¹ and from 65 ± 6 to 62 ± 1% (p < 0.05), respectively. No significant changes were observed in the jugular venous oxygen saturation (p > 0.05) nor in any of the electroencephalogram derived indices (p > 0.05). Correlation analysis revealed strong positive significant correlations between cerebral oxygen saturation and cardiac output (r = 0.82, p < 0.001) and between cerebral oxygen saturation and approximate entropy (r = 0.65, p < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE The effect caused by the remifentanil bolus on the brain oxygenation seems to be better reflected by the cerebral oxygen saturation than the jugular venous oxygen saturation. The effect of remifentanil on the electroencephalogram may not be reflected in indices derived from the electroencephalogram, but the potential of the approximate entropy in reflecting changes caused by opioids on the electroencephalogram should be further investigated.
Collapse
Affiliation(s)
- Aura Silva
- Toxicology, REQUIMTE, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
| | | | | | | | | | | |
Collapse
|
14
|
Influence of PEEP on cerebral blood flow and cerebrovascular autoregulation in patients with acute respiratory distress syndrome. J Neurosurg Anesthesiol 2013; 25:162-7. [PMID: 23211642 DOI: 10.1097/ana.0b013e31827c2f46] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND High levels of positive end-expiratory pressure (PEEP), as part of the treatment in patients with acute respiratory distress syndrome (ARDS), may prevent alveolar collapse and maintain oxygenation. PEEP potentially reduces cerebral venous return, increases intracranial blood volume, and may, therefore, affect cerebral blood flow (CBF) and cerebrovascular autoregulation (AR). This study investigates the effect of PEEP on CBF and AR in patients with respiratory failure. METHODS CBF velocity was measured using transcranial doppler and correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was measured at lower PEEP levels and after increasing PEEP. Only an increase of Mx of >0.2 was considered to be clinically relevant. Two 1-sided Wilcoxon tests. RESULTS Twenty mechanically ventilated patients with ARDS were included. Elevation of PEEP from 9.2±1 to 14.3±1 cm H2O did not influence CBF velocity but increased Mx from 0.317±0.35 to 0.414±0.32 (difference ≤0.2). Mx was >0.3 in 11/20 patients during baseline measurements, indicating impaired AR. CONCLUSIONS Surprisingly, AR was impaired in 55% of the patients with ARDS. This should be taken into account when managing cerebral perfusion pressure to avoid cerebral hyperperfusion or hypoperfusion. Increasing PEEP from 9.2 to 14.3 cm H2O had no further clinically relevant effect on AR, independent of preexisting AR impairment.
Collapse
|
15
|
Cerebrovascular autoregulation in critically ill patients during continuous hemodialysis. Can J Anaesth 2013; 60:564-9. [PMID: 23536386 DOI: 10.1007/s12630-013-9912-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 02/20/2013] [Indexed: 10/27/2022] Open
Abstract
PURPOSE In chronic renal failure, intermittent hemodialysis decreases cerebral blood flow velocity (CBFV); however, in critically ill patients with acute renal failure, the effect of continuous venovenous hemodialysis (CVVHD) on CBFV and cerebrovascular autoregulation (AR) is unknown. Therefore, a study was undertaken to investigate the potential effect of CVVHD on CBFV and AR in patients with acute renal failure. METHODS This cohort study investigated 20 patients with acute renal failure who required CVVHD. In these patients, the CBFV and index of AR (Mx) were measured using transcranial Doppler before and during CVVHD. RESULTS The median Mx values at baseline were 0.33 [interquartile range (IQR): 0.02-0.55], and during CVVHD, they were 0.20 [0.07-0.40]. The differences in Mx (CVVHD--baseline) was (median [IQR]) -0.015 [-0.19-0.05], 95% confidence interval (CI) -0.16 to 0.05. The Mx was > 0.3 in 11/20 patients at baseline measurement. Six of these patients recovered to Mx < 0.3 during CVVHD. The CBFV was (median [IQR]) 47 [36-59] cm · sec(-1) at baseline and 49 [36-66] cm · sec(-1) during CVVHD. The difference of CBFV was 0.0 [-4 - 2.7], 95% CI -2.5 to 4.2. CONCLUSION Compared with patients with intermittent hemodialysis, CVVHD did not influence CBFV and AR in critically ill patients with acute renal failure, possibly due to lower extracorporeal blood flow, slower change of plasma osmolarity, and a lower fluid extraction rate. In a subgroup of patients with sepsis, the AR was impaired at baseline in more than half of the patients, and this was reversed during CVVHD. The trial was registered at ClinicalTrials.gov ID: NCT01376531.
Collapse
|
16
|
Schramm P, Klein KU, Falkenberg L, Berres M, Closhen D, Werhahn KJ, David M, Werner C, Engelhard K. Impaired cerebrovascular autoregulation in patients with severe sepsis and sepsis-associated delirium. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2012; 16:R181. [PMID: 23036135 PMCID: PMC3682283 DOI: 10.1186/cc11665] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 10/04/2012] [Indexed: 11/10/2022]
Abstract
Introduction Sepsis-associated delirium (SAD) increases morbidity in septic patients and, therefore, factors contributing to SAD should be further characterized. One possible mechanism might be the impairment of cerebrovascular autoregulation (AR) by sepsis, leading to cerebral hypo- or hyperperfusion in these haemodynamically unstable patients. Therefore, the present study investigates the relationship between the incidence of SAD and the status of AR during sepsis. Methods Cerebral blood flow velocity was measured using transcranial Doppler sonography and was correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was measured daily during the first 4 days of sepsis. Diagnosis of a SAD was performed using the confusion assessment method for ICU (CAM-ICU) and, furthermore the predominant brain electrical activity in electroencephalogram (EEG) both at day 4 after reduction of sedation to RASS >-2. Results 30 critically ill adult patients with severe sepsis or septic shock (APACHE II 32 ± 6) were included. AR was impaired at day 1 in 60%, day 2 in 59%, day 3 in 41% and day 4 in 46% of patients; SAD detected by CAM-ICU was present in 76 % of patients. Impaired AR at day 1 was associated with the incidence of SAD at day 4 (p = 0.035). Conclusions AR is impaired in the great majority of patients with severe sepsis during the first two days. Impaired AR is associated with SAD, suggesting that dysfunction of AR is one of the trigger mechanisms contributing to the development of SAD. Trial registration clinicalTrials.gov ID NCT01029080
Collapse
|
17
|
Serial Measurement of Static and Dynamic Cerebrovascular Autoregulation After Brain Injury. J Neurosurg Anesthesiol 2011; 23:41-4. [DOI: 10.1097/ana.0b013e3181f35854] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
18
|
Lee JH, Lee Y, In J, Chung SH, Shin HI, Lee K, Kim KO, Cho H. Response of cerebral oximetry to increase in alveolar concentration of desflurane: effect of remifentanil and cerebrovascular CO 2reactivity. Korean J Anesthesiol 2009; 56:543-551. [DOI: 10.4097/kjae.2009.56.5.543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jeoung Hyuk Lee
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Younsuk Lee
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Junyong In
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Seung-Hyun Chung
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Hong-il Shin
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Kyoungjin Lee
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Kyoung Ok Kim
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| | - Hun Cho
- Department of Anesthesiology and Pain Medicine, Dongguk University College of Medicine, Ilsan Hospital, Goyang, Korea
| |
Collapse
|
19
|
Abstract
BACKGROUND AND AIM Remifentanil is an ultra-short-acting opioid, increasingly used today in neuroanesthesia and neurointensive care. Its characteristics make remifentanil a potentially ideal agent, but previous data have cast a shadow on this opioid, supporting potentially toxic effects on the ischemic brain. The aim of the present concise review is to survey available up-to-date information on the effects of remifentanil on the central nervous system. METHOD A MEDLINE search within the past seven years for available up-to-date information on remifentanil and brain was performed. RESULTS Concise up-to-date information on the effects of remifentanil on the central nervous system was reported, with a particular emphasis on the following topics: cerebral metabolism, electroencephalogram, electrocorticography, motor-evoked potentials, regional cerebral blood flow, cerebral blood flow velocity, arterial hypotension and hypertension, intracranial pressure, cerebral perfusion pressure, cerebral autoregulation, cerebrovascular CO(2) reactivity, cerebrospinal fluid, painful stimulation, analgesia and hyperalgesia, neuroprotection, neurotoxicity and hypothermia. CONCLUSION The knowledge of the influence of remifentanil on brain functions is crucial before routine use in neuroanesthesia to improve anesthesia performance and patient safety as well as outcome.
Collapse
Affiliation(s)
- V Fodale
- Department of Neuroscience, Psychiatric and Anesthesiological Sciences, University of Messina, Messina, Italy.
| | | | | | | |
Collapse
|
20
|
Fodale V, Schifilliti D, Conti A, Lucanto T, Pino G, Santamaria LB. Transcranial Doppler and anesthetics. Acta Anaesthesiol Scand 2007; 51:839-47. [PMID: 17635391 DOI: 10.1111/j.1399-6576.2007.01355.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Transcranial Doppler (TCD) is widely used to investigate the effects of anesthetic drugs on cerebral blood flow. Its repeatability and non-invasivity makes it an ideal, first choice method. Anesthesia providers are required to be conscious of the cerebral hemodynamic effects of drugs given in their practice, especially in neurosurgery and in subjects with impaired brain functions. The purpose of this review is to present the basic concepts of the TCD technique and the effects on cerebral hemodynamics of the most popular anesthetic drugs evaluated using TCD ultrasonography.
Collapse
Affiliation(s)
- V Fodale
- Department of Neuroscience, Psychiatric and Anesthesiological Sciences, University of Messina, Messina, Italy.
| | | | | | | | | | | |
Collapse
|
21
|
Hlatky R, Valadka AB, Robertson CS. Analysis of dynamic autoregulation assessed by the cuff deflation method. Neurocrit Care 2006; 4:127-32. [PMID: 16627900 DOI: 10.1385/ncc:4:2:127] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Dynamic testing of cerebral pressure autoregulation is more practical than static testing for critically ill patients. The process of cuff deflation is innocuous in the normal subject, but the systemic and cerebral effects of cuff deflation in severely head-injured patients have not been studied. The purposes of this study were to examine the physiological effects of cuff deflation and to study their impact on the calculation of autoregulatory index (ARI). METHOD In 24 severely head-injured patients, 388 thigh cuff deflations were analyzed. The physiological parameters were recorded before, during, and after a transient decrease in blood pressure. Autoregulation was graded by generating an ARI value from 0 to 9. RESULTS Mean arterial blood pressure (MAP) dropped rapidly during the first 2-3 seconds, but the nadir MAP was not reached until 8 +/- 7 seconds after the cuff deflation. MAP decreased by an average value of 19 +/- 5 mmHg. Initially the tracings for MAP and cerebral perfusion pressure (CPP) were nearly identical, but after 30 seconds, variable increases in intracranial pressure caused some differences between the MAP and CPP curves. The difference between the ARI values calculated twice using MAP as well as CPP was zero for 70% of left-sided studies and 73% for right-sided studies and less than or equal to 1 for 93% of left- and 95% of right-sided cuff deflations. CONCLUSION Transient and relatively minor perturbations were detected in systemic physiology induced by dynamic testing of cerebral pressure autoregulation. Furthermore, this study confirms that the early changes in MAP and CPP after cuff deflation are nearly identical. MAP can substitute for CPP in the calculation of ARI even in the severely brain-injured patient.
Collapse
Affiliation(s)
- Roman Hlatky
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA.
| | | | | |
Collapse
|
22
|
Conti A, Iacopino DG, Fodale V, Micalizzi S, Penna O, Santamaria LB. Cerebral haemodynamic changes during propofol-remifentanil or sevoflurane anaesthesia: transcranial Doppler study under bispectral index monitoring. Br J Anaesth 2006; 97:333-9. [PMID: 16829673 DOI: 10.1093/bja/ael169] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Sevoflurane or propofol-remifentanil-based anaesthetic regimens represent modern techniques for neurosurgical anaesthesia. Nevertheless, there are potential differences related to their activity on the cerebrovascular system. The magnitude of such difference is not completely known. METHODS In total 40 patients, treated for spinal or maxillo-facial disorders, were randomly allocated to either i.v. propofol-remifentanil or inhalational sevoflurane anaesthesia. Transcranial Doppler was used to assess changes in cerebral blood flow velocity, carbon dioxide reactivity, cerebral autoregulation and the bispectral index to assess the depth of anaesthesia. RESULTS Time-averaged mean flow velocity (MFV) was significantly reduced after induction of anaesthesia in both sevoflurane and propofol-remifentanil groups (P<0.001). At deeper levels of anaesthesia, MFV increased in the sevoflurane group, suggesting an uncoupling flow/metabolism, whereas it was further reduced in the propofol-remifentanil group (P<0.001). Indices of cerebral autoregulation were reduced in patients with high-dose sevoflurane whereas autoregulation was preserved in patients anaesthetized with propofol-remifentanil (P<0.001). Higher CO(2) concentrations impaired cerebral autoregulation in the sevoflurane group but not in patients anaesthetized with propofol-remifentanil. CONCLUSIONS Propofol-remifentanil anaesthesia induced a dose-dependent low-flow state with preserved cerebral autoregulation, whereas sevoflurane at high doses provided a certain degree of luxury perfusion.
Collapse
Affiliation(s)
- A Conti
- Department of Neurosciences, Psychiatric and Anaesthesiological Sciences, University of Messina, School of Medicine, Policlinico Universitario "G. Martino", via C.Valeria 98125, Messina, Italy
| | | | | | | | | | | |
Collapse
|
23
|
Werner C, Lu H, Engelhard K, Unbehaun N, Kochs E. Sevoflurane Impairs Cerebral Blood Flow Autoregulation in Rats: Reversal by Nonselective Nitric Oxide Synthase Inhibition. Anesth Analg 2005; 101:509-516. [PMID: 16037169 DOI: 10.1213/01.ane.0000160586.71403.a4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED In this study, we investigated the effects of 1.0 and 2.0 minimum alveolar anesthetic concentration (MAC) sevoflurane on cerebral blood flow (CBF) autoregulation before and after nonselective inhibition of nitric oxide (NO) synthase in rats. Rats were randomly assigned as follows: Group 1 (n = 8): 1.0 MAC sevoflurane; Groups 2 and 3 (n = 8 per group): 2.0 MAC sevoflurane. Assessment of autoregulation within a mean arterial blood pressure range of 140-60 mm Hg was performed by graded hemorrhage before and after administration of l-arginine methyl ester (l-NAME, 30 mg/kg IV, Groups 1 and 2) or during hypocapnia (Group 3). In 10 additional animals, brain tissue NO(2)(-) concentrations were measured at 1.0 and 2.0 MAC sevoflurane. CBF autoregulation was maintained with 1.0 MAC sevoflurane (Group 1) regardless of NO synthase status indicating that CBF autoregulation might not be related to NO availability. Sevoflurane dose-dependently increased brain tissue NO(2)(-) and impaired CBF autoregulation. Administration of l-NAME (Group 2) but not hypocapnia (Group 3) restored CBF autoregulation. This suggests that sevoflurane impairs the autoregulatory capacity secondary to an increase of the perivascular NO availability and questions the importance of basal cerebrovascular tone in terms of vasodilatory capacity during hypotensive challenges. IMPLICATIONS The present study suggests that the volatile anesthetic sevoflurane dose-dependently impairs cerebrovascular autoregulation by mechanisms secondary to increase of perivascular nitric oxide availability.
Collapse
Affiliation(s)
- Christian Werner
- *Klinik für Anästhesiologie, Johannes Gutenberg-Universität, Mainz; †Klinik für Anaesthesiologie and ‡Chirurgische Klinik und Poliklinik, Technische Universität, München, Germany
| | | | | | | | | |
Collapse
|
24
|
Abstract
The anilidopiperidine opioid remifentanil has pharmacodynamic properties similar to all opioids; however, its pharmacokinetic characteristics are unique. Favourable pharmacokinetic properties, minimally altered by extremes of age or renal or hepatic dysfunction, enable easy titration and rapid dissipation of clinical effect of this agent, even after prolonged infusion. Remifentanil is metabolised by esterases that are widespread throughout the plasma, red blood cells, and interstitial tissues, whereas other anilidopiperidine opioids (e.g. fentanyl, alfentanil and sufentanil) depend upon hepatic biotransformation and renal excretion for elimination. Consequently, remifentanil is cleared considerably more rapidly than other anilidopiperidine opioids. In addition, its pKa (the pH at which the drug is 50% ionised) is less than physiological pH; thus, remifentanil circulates primarily in the non-ionised moiety, which quickly penetrates the lipid blood-brain barrier and rapidly equilibrates across the plasma/effect site interface. By virtue of these distinctive pharmacokinetic properties, the context-sensitive half-time (i.e. the time required for the drug's plasma concentration to decrease by 50% after cessation of an infusion) of remifentanil remains consistently short (3.2 minutes), even following an infusion of long duration (> or =8 hours). Remifentanil, a clinically versatile opioid, is useful for intravenous analgesia and sedation in spontaneously breathing patients undergoing painful procedures. Profound analgesia may be achieved with minimal effect on cognitive function. Remifentanil may also provide sedation and analgesia during placement of regional anaesthetic blocks, and in conjunction with topical anaesthesia and airway nerve blocks, it may be useful for blunting reflex responses and facilitating 'awake' fibreoptic intubation. Compared with fentanyl and alfentanil in a day-surgery setting, remifentanil supplementation of general anaesthesia may improve intraoperative haemodynamic control. Both emergence time and the incidence of respiratory depression during post-anaesthetic recovery may be reduced. However, outcomes such as home discharge time, post-emergence adverse effect profile, and patient and provider satisfaction are not significantly improved, and the incidence of intraoperative hypotension and bradycardia is greater. In addition, drug acquisition costs for remifentanil are higher and clinicians may need extra time to familiarise themselves with the drug's unique pharmacokinetics.Ironically, the quick dissipation of opioid analgesic effect following remifentanil discontinuation may be a significant clinical disadvantage. Unless little or no postoperative pain is anticipated, the clinician may wish to treat prospectively using local or regional anaesthesia, non-opioid analgesics, or longer-acting opioid analgesics.
Collapse
Affiliation(s)
- Richard Beers
- Department of Anesthesiology, SUNY Upstate Medical University, Syracuse, New York 13210, USA.
| | | |
Collapse
|
25
|
Abstract
Remifentanil (Ultiva), a fentanyl derivative, is an ultra-short acting, nonspecific esterase-metabolised, selective mu-opioid receptor agonist, with a pharmacodynamic profile typical of opioid analgesic agents. Notably, the esterase linkage in remifentanil results in a unique and favourable pharmacokinetic profile for this class of agent. Adjunctive intravenous remifentanil during general anaesthesia is an effective and generally well tolerated opioid analgesic in a broad spectrum of patients, including adults and paediatric patients, undergoing several types of surgical procedures in both the inpatient and outpatient setting. Remifentanil is efficacious in combination with intravenous or volatile hypnotic agents, with these regimens generally being at least as effective as fentanyl- or alfentanil-containing regimens in terms of attenuation of haemodynamic, autonomic and somatic intraoperative responses, and postoperative recovery parameters. The rapid offset of action and short context-sensitive half-time of remifentanil, irrespective of the duration of the infusion, makes the drug a valuable opioid analgesic option for use during balanced general inhalational or total intravenous anaesthesia (TIVA) where rapid, titratable, intense analgesia of variable duration, and a fast and predictable recovery are required.
Collapse
|
26
|
Lagace A, Karsli C, Luginbuehl I, Bissonnette B. The effect of remifentanil on cerebral blood flow velocity in children anesthetized with propofol. Paediatr Anaesth 2004; 14:861-5. [PMID: 15385016 DOI: 10.1111/j.1460-9592.2004.01323.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Cerebrovascular stability and rapid anesthetic emergence are desirable features of a neuroanesthetic regimen. In this randomized crossover study the effect of a low-dose remifentanil infusion on cerebral blood flow velocity (CBFV) in children anesthetized with propofol was evaluated. METHODS Twenty healthy children aged 1-6 years undergoing urological surgery were enrolled. Following face mask induction with sevoflurane, anesthesia was maintained with a standardized propofol infusion. Rocuronium was used to facilitate tracheal intubation and normothermia, and normocapnia were maintained. All children received a caudal epidural block, and a transcranial Doppler probe was placed to measure middle cerebral artery blood flow velocity (Vmca). Each patient received a remifentanil regimen of 0.5 microg x kg(-1) followed by 0.2 microg x kg(-1) x min(-1) in a predetermined order of remifentanil + propofol or propofol alone. Vmca, mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously at equilibrium with and without remifentanil. RESULTS The combination of remifentanil and propofol caused an 8.1% decrease in MAP (P = 0.0005) and an 11.8% decrease in HR (P < 0.0001) compared with propofol alone. Vmca was not different between the two groups (P = 0.4041). CONCLUSION The addition of remifentanil to propofol anesthesia in children causes a reduction in MAP and HR without affecting CBFV. This may imply that cerebral blood pressure autoregulation is preserved in children under propofol and remifentanil anesthesia.
Collapse
Affiliation(s)
- Annie Lagace
- Department of Anaesthesia, University of Toronto, Toronto, Ontario, Canada
| | | | | | | |
Collapse
|
27
|
Abstract
Remifentanil is the latest available compound of the 4-anilidopiperidine derivatives. It is characterized by an ultrashort duration of action and a metabolism independent of both hepatic and renal functions. Its main drawback is a lack of residual analgesia and the risk of postoperative hyperalgesia. Since its introduction in clinical practice, this drug has been compared to other congeners in a few studies in the setting of neurosurgery. Cerebral hemodynamics, intracranial pressure and CO(2) reactivity are similar to the effects of fentanyl and sufentanil provided that systemic arterial pressure is maintained. Haemodynamics does not greatly vary according to the type of the opioid. Fentanyl and sufentanil require higher hypnotic dosage (halogenated agents, propofol) and remifentanil is accompanied by greater volumes of fluid infusion. A marked reduction in extubation times and superior level of consciousness are reported with remifentanil. Rescue analgesic has to be given faster but pain scores remain low. Morphine 0.08 mg/kg IV administered at bone replacement results in good postoperative analgesia without delayed recovery. In summary, remifentanil is appropriate when rapid recovery and neurological evaluation are desired. Conversely, sufentanil is more suitable and easier to administer when postoperative mechanical ventilation and postponed awakening are scheduled.
Collapse
Affiliation(s)
- X Viviand
- Département d'anesthésie-réanimation et centre de traumatologie, hôpital Nord, 13915 Marseille cedex 20, France.
| | | |
Collapse
|
28
|
Schmitz B, Nimsky C, Wendel G, Wienerl J, Ganslandt O, Jacobi K, Fahlbusch R, Schüttler J. Anesthesia during high-field intraoperative magnetic resonance imaging experience with 80 consecutive cases. J Neurosurg Anesthesiol 2003; 15:255-62. [PMID: 12826974 DOI: 10.1097/00008506-200307000-00014] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Intraoperative magnetic resonance imaging (MRI) has been used for years to update neuronavigation and for intraoperative resection control. For this purpose, low-field (0.1-0.2 T) MR scanners have been installed in the operating room, which, in contrast to machines using higher magnetic field strength, allowed the use of standard anesthetic and surgical equipment. However, these low-field MR systems provided only minor image quality and a limited battery of MR sequences, excluding functional MRI, diffusion-weighted MRI, or MR angiography and spectroscopy. Based on these advantages, a concept using high-field MRI (1.5 T) with intraoperative functional neuronavigational guidance has been developed that required adaptation of the anesthetic regimen to working in the close vicinity to the strong magnetic field. In this paper the authors present their experience with the first 80 consecutive patients who received anesthesia in a specially designed radio frequency-shielded operating room equipped with a high-field (1.5 T) MR scanner. We describe the MR-compatible anesthesia equipment used including ventilator, monitoring, and syringe pumps, which allow standard neuroanesthesia in this new and challenging environment. This equipment provides the use of total intravenous anesthesia with propofol and remifentanil allowing rapid extubation and neurologic examination following surgery. In addition, extended intraoperative monitoring including EEG monitoring required for intracranial surgery is possible. Moreover, problems and dangers related to the effects of the strong magnetic field are discussed.
Collapse
Affiliation(s)
- Bernd Schmitz
- Department of Anesthesiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Myburgh JA, Upton RN, Grant C, Martinez A. The effect of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under isoflurane anaesthesia in an ovine model. Anaesth Intensive Care 2003; 31:259-66. [PMID: 12879669 DOI: 10.1177/0310057x0303100303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effects of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under steady-state isoflurane anaesthesia were compared with the awake state. Six studies each were conducted in two cohorts of adult ewes: awake sheep and those anaesthetized with 2% isoflurane anaesthesia. In random order, each animal received ramped infusions of adrenaline, noradrenaline (0-40 micrograms/min) and dopamine (0-40 micrograms/kg/min). Cerebral blood flow was measured continuously from changes in Doppler velocities in the sagittal sinus. Autoregulation was determined by linear regression analysis between cerebral blood flow and mean arterial pressure. Isoflurane did not significantly alter cerebral blood flow relative to pre-anaesthesia values (P > 0.05). All three catecholamines significantly and equivalently increased MAP from baseline in a dose dependent manner in both the awake and isoflurane cohorts. Although adrenaline significantly increased cerebral blood flow from baseline in the awake cohort (P < 0.01), none of the catecholamines significantly increased cerebral blood flow during isoflurane anaesthesia. No significant differences were demonstrated between the slopes and intercepts of regression lines for adrenaline, noradrenaline and dopamine within either cohort (ANCOVA). Inter-cohort comparisons between the two autoregulation curves demonstrated no significant difference between the slopes of the autoregulation curves for the awake (pooled slope = 0.39) and isoflurane cohorts (pooled slope = 0.28) (P > 0.05). Over a specific dose range, systemic hypertension induced by adrenaline, noradrenaline and dopamine did not significantly increase cerebral blood flow under 2% isoflurane anaesthesia. The concomitant administration of isoflurane and the catecholamines was not associated with altered autoregulatory function compared to the awake state.
Collapse
Affiliation(s)
- J A Myburgh
- Department of Anaesthesia and Intensive Care, University of Adelaide, Adelaide, South Australia
| | | | | | | |
Collapse
|
30
|
Myburgh JA, Upton RN, Grant C, Martinez A. The effect of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under propofol anaesthesia in an ovine model. Intensive Care Med 2003; 29:817-24. [PMID: 12595982 DOI: 10.1007/s00134-003-1684-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2002] [Accepted: 01/21/2003] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To compare the effects of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under steady-state propofol anaesthesia with the awake state. DESIGN Prospective, randomised, interventional animal study. SETTING University laboratory. SUBJECTS Six studies in two cohorts of adult ewes: awake and steady-state propofol anaesthesia (15 mg/min). INTERVENTIONS In random order, each animal received ramped infusions of adrenaline, noradrenaline (0-40 microg/min) and dopamine (0-40 microg/kg per min). MEASUREMENTS AND RESULTS Cerebral blood flow (CBF) was measured continuously from changes in Doppler velocities in the sagittal sinus and normalised to a PaCO(2) 35 mmHg. Propofol decreased CBF by 55% relative to pre-anaesthesia values (p=0.0001). All three catecholamines significantly and equivalently increased mean arterial pressure (MAP) from baseline in a dose-dependent manner in both awake and propofol cohorts. Adrenaline significantly increased CBF from baseline in both awake sheep (p<0.01) and during propofol anaesthesia (p<0.001); noradrenaline and dopamine did not statistically increase CBF. When comparing the effects of individual catecholamines with each other within each cohort, no statistically significant difference between the catecholamines was demonstrated. (p>0.05). Using linear regression analysis, normalised CBF was correlated against associated changes in MAP. No significant differences were demonstrated between the slopes of regression lines for adrenaline, noradrenaline and dopamine in either cohort (ANCOVA). There was a statistically significant difference between the intercepts of the awake and propofol cohorts (p<0.0001), but no difference between the slopes (p=0.69). CONCLUSIONS Over a specific dose range, catecholamine-induced hypertension caused increased CBF during steady-state propofol anaesthesia. This effect was offset by an associated reduction in CBF caused by propofol. The concomitant administration of propofol and catecholamines was not associated with altered autoregulatory function compared to the awake state.
Collapse
Affiliation(s)
- John A Myburgh
- Department of Anaesthesia and Intensive Care, University of Adelaide and Royal Adelaide Hospital, 5000 Adelaide, Australia.
| | | | | | | |
Collapse
|
31
|
McCulloch TJ, Thompson CL, Dunne V. Cerebral hemodynamics immediately following carotid occlusion. J Neurosurg Anesthesiol 2003; 15:126-30. [PMID: 12657998 DOI: 10.1097/00008506-200304000-00010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
During carotid endarterectomy, we routinely monitor internal carotid artery pressure (P(ICA)) and middle cerebral artery flow velocity (V(MCA)). P(ICA) has been previously shown to accurately reflect pressure at the origin of the middle cerebral artery, even during times of rapidly changing pressure such as occurs with sudden occlusion of the common carotid artery. We retrospectively analyzed pressure recordings around the time of carotid cross clamping in 29 consecutive carotid endarterectomy operations. Suitable transcranial Doppler recordings of V(MCA) were available from eight of the operations. Comparing the cardiac cycle prior to cross clamping with the first complete cardiac cycle after cross clamping, the mean P(ICA) fell from 93 mm Hg to 62 mm Hg and the mean V(MCA) fell from 41 cm x sec-1 to 25 cm x sec-1. Over the subsequent 10 seconds, there was a further decrease in P(ICA) to 51 mm Hg (P <.0001), while V(MCA) changed in the opposite direction, increasing to 32 cm x sec-1 (P <.01). The patients with the greatest decrease in P(ICA) immediately on cross clamping also had the greatest additional decrease over the following 10 seconds (r = 0.74). The increase in V(MCA) during the first 10 seconds after carotid occlusion is well recognized and is presumed to be due to autoregulatory vasodilatation. The simultaneous decrease that we observed in P(ICA) indicates an increase in the pressure gradient along the collateral vessels, which is to be expected during a period of increasing flow along those vessels.
Collapse
|
32
|
Vavilala MS, Newell DW, Junger E, Douville CM, Aaslid R, Rivara FP, Lam AM. Dynamic cerebral autoregulation in healthy adolescents. Acta Anaesthesiol Scand 2002; 46:393-7. [PMID: 11952439 DOI: 10.1034/j.1399-6576.2002.460411.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND : There is little information on the limits of cerebral autoregulation and the autoregulatory capacity in children. The aim of this study was to compare dynamic cerebral autoregulation between healthy adolescents and adults. METHODS : Seventeen healthy volunteers 12-17 years (n = 8) and 25-45 years (n = 9) were enrolled in this study. Bilateral mean middle cerebral artery flow velocities (Vmca; (cm/s)) were measured using transcranial Doppler ultrasonography (TCD). Mean arterial blood pressure (MAP) and end-tidal carbon dioxide were measured continuously during dynamic cerebral autoregulation studies. Blood pressure cuffs were placed around both thighs and inflated to 30 mmHg above the systolic blood pressure for 3 min and then rapidly deflated, resulting in transient systemic hypotension. The change of Vmca to change in MAP constitutes the autoregulatory response, and the speed of this response was quantified using computer model parameter estimation. The dynamic autoregulatory index (ARI) was averaged between the two sides. RESULTS : Adolescents had significantly lower ARI (3.9 +/- 2.1 vs. 5.3 +/- 0.8; P=0.05), and higher Vmca (75.2 +/- 15.2 vs. 57.6 +/- 15.0; P<0.001) than adults. CONCLUSION : The autoregulatory index is physiologically lower in normal adolescents 12-17 years of age than in adults.
Collapse
Affiliation(s)
- M S Vavilala
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
| | | | | | | | | | | | | |
Collapse
|