scholarly journals Effect of dexmedetomidine on dynamic cerebral autoregulation and carbon dioxide reactivity during sevoflurane anesthesia in healthy patients

2020 ◽  
Vol 73 (4) ◽  
pp. 311-318
Author(s):  
Sujoy Banik ◽  
Girija Prasad Rath ◽  
Ritesh Lamsal ◽  
Parmod K Bithal
Keyword(s):  
Carbon Dioxide ◽  
Spine Surgery ◽  
Cerebral Autoregulation ◽  
Lumbar Spine Surgery ◽  
Skin Closure ◽  
Sevoflurane Anesthesia ◽  
Co2 Reactivity ◽  
The Right ◽  
Group D ◽  
Dynamic Cerebral Autoregulation

Background: There are conflicting opinions on the effect of dexmedetomidine on cerebral autoregulation. This study assessed its effect on dynamic cerebral autoregulation (dCA) using a transcranial Doppler (TCD).Methods: Thirty American Society of Anesthesiologists physical status I and II patients between 18 and 60 years, who underwent lumbar spine surgery, received infusions of dexmedetomidine (Group D) or normal saline (Group C), followed by anesthesia with propofol and fentanyl, and maintenance with oxygen, nitrous oxide and sevoflurane. After five minutes of normocapnic ventilation and stable bispectral index value (BIS) of 40-50, the right middle cerebral artery flow velocity (MCAFV) was recorded with TCD. The transient hyperemic response (THR) test was performed by compressing the right common carotid artery for 5-7 seconds. The lungs were hyperventilated to test carbon dioxide (CO2) reactivity. Hemodynamic parameters, arterial CO2 tension, pulse oximetry (SpO2), MCAFV and BIS were measured before and after hyperventilation. Dexmedetomidine infusion was discontinued ten minutes before skin-closure. Time to recovery and extubation, modified Aldrete score, and emergence agitation were recorded. Results: Demographic parameters, durations of surgery and anesthesia, THR ratio (Group D: 1.26 ± 0.11 vs. Group C: 1.23 ± 0.04; P = 0.357), relative CO2 reactivity (Group D: 1.19 ± 0.34 %/mmHg vs. Group C: 1.23 ± 0.25 %/mmHg; P = 0.547), blood pressure, SpO2, BIS, MCAFV, time to recovery, time to extubation and modified Aldrete scores were comparable. Conclusions: Dexmedetomidine administration does not impair dCA and CO2 reactivity in patients undergoing spine surgery under sevoflurane anesthesia.

Dynamic Cerebral Autoregulation During Sevoflurane Anesthesia

1999 ◽  
Vol 88 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Andrew C. Summors ◽  
Arun K. Gupta ◽  
Basil F. Matta
Keyword(s):  
Cerebral Autoregulation ◽  
Sevoflurane Anesthesia ◽  
Dynamic Cerebral Autoregulation

Dynamic cerebral autoregulation during brain activation paradigms

2005 ◽  
Vol 289 (3) ◽  
pp. H1202-H1208 ◽  
Author(s):  
Ronney B. Panerai ◽  
Michelle Moody ◽  
Penelope J. Eames ◽  
John F. Potter
Keyword(s):  
Transfer Function ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Brain Activation ◽  
Hemispheric Lateralization ◽  
Step Response ◽  
Arterial Blood ◽  
Transfer Function Analysis ◽  
The Right ◽  
Dynamic Cerebral Autoregulation

Dynamic cerebral autoregulation (CA) describes the transient response of cerebral blood flow (CBF) to rapid changes in arterial blood pressure (ABP). We tested the hypothesis that the efficiency of dynamic CA is increased by brain activation paradigms designed to induce hemispheric lateralization. CBF velocity [CBFV; bilateral, middle cerebral artery (MCA)], ABP, ECG, and end-tidal Pco2 were continuously recorded in 14 right-handed healthy subjects (21–43 yr of age), in the seated position, at rest and during 10 repeated presentations (30 s on-off) of a word generation test and a constructional puzzle. Nonstationarities were not found during rest or activation. Transfer function analysis of the ABP-CBFV (i.e., input-output) relation was performed for the 10 separate 51.2-s segments of data during activation and compared with baseline data. During activation, the coherence function below 0.05 Hz was significantly increased for the right MCA recordings for the puzzle tasks compared with baseline values (0.36 ± 0.16 vs. 0.26 ± 0.13, P < 0.05) and for the left MCA recordings for the word paradigm (0.48 ± 0.23 vs. 0.29 ± 0.16, P < 0.05). In the same frequency range, significant increases in gain were observed during the puzzle paradigm for the right (0.69 ± 0.37 vs. 0.46 ± 0.32 cm·s−1·mmHg−1, P < 0.05) and left (0.61 ± 0.29 vs. 0.45 ± 0.24 cm·s−1·mmHg−1, P < 0.05) hemispheres and during the word tasks for the left hemisphere (0.66 ± 0.31 vs. 0.39 ± 0.15 cm·s−1·mmHg−1, P < 0.01). Significant reductions in phase were observed during activation with the puzzle task for the right (−0.04 ± 1.01 vs. 0.80 ± 0.86 rad, P < 0.01) and left (0.11 ± 0.81 vs. 0.57 ± 0.51 rad, P < 0.05) hemispheres and with the word paradigm for the right hemisphere (0.05 ± 0.87 vs. 0.64 ± 0.59 rad, P < 0.05). Brain activation also led to changes in the temporal pattern of the CBFV step response. We conclude that transfer function analysis suggests important changes in dynamic CA during mental activation tasks.

Cerebral Autoregulation and CO2 Reactivity in Anterior and Posterior Cerebral Circulation During Sevoflurane Anesthesia

2006 ◽  
Vol 102 (2) ◽  
pp. 560-564 ◽  
Author(s):  
Irene Rozet ◽  
Monica S. Vavilala ◽  
Andrew M. Lindley ◽  
Elizabeth Visco ◽  
Miriam Treggiari ◽  
...  
Keyword(s):  
Cerebral Circulation ◽  
Cerebral Autoregulation ◽  
Sevoflurane Anesthesia ◽  
Co2 Reactivity ◽  
Posterior Cerebral Circulation

Ischemic optic neuropathy following lumbar spine surgery

1995 ◽  
Vol 83 (2) ◽  
pp. 348-349 ◽  
Author(s):  
Andrew G. LEE
Keyword(s):  
Blood Pressure ◽  
Lumbar Spine ◽  
Spine Surgery ◽  
Optic Neuropathy ◽  
Visual Loss ◽  
Lumbar Spine Surgery ◽  
Ischemic Optic Neuropathy ◽  
Content Type ◽  
The Right ◽  
Fine Print

✓ This 48-year-old hypertensive man, a cigarette smoker, awoke in the recovery room with visual loss in the right eye after uncomplicated lumbar spine surgery. His intraoperative blood pressure had been maintained at relatively low levels to reduce bleeding; a loss of 1500 cc of blood was reported. Postoperative hemoglobin was 4.2 g/dl less than the preoperative hemoglobin; however, the patient did not receive a blood transfusion. A postoperative ophthalmological examination revealed decreased visual acuity, color vision, and visual field in the right eye. The right optic nerve and retina were initially normal but the patient eventually developed optic nerve atrophy consistent with the clinical diagnosis of ischemic optic neuropathy. Neurosurgeons should be aware that this condition may follow uncomplicated lumbar spine surgery and should obtain prompt ophthalmological consultation when patients develop postoperative visual loss. Aggressive and rapid correction of blood pressure and hematocrit may be helpful in individuals who develop ischemic optic neuropathy after lumbar spine surgery.

Graded Hypercapnia and Cerebral Autoregulation during Sevoflurane or Propofol Anesthesia

2000 ◽  
Vol 93 (5) ◽  
pp. 1205-1209 ◽  
Author(s):  
Timothy J. McCulloch ◽  
Elizabeth Visco ◽  
Arthur M. Lam
Keyword(s):  
Carbon Dioxide ◽  
General Anesthesia ◽  
Cerebral Autoregulation ◽  
Carbon Dioxide Partial Pressure ◽  
Sevoflurane Anesthesia ◽  
Significant Difference ◽  
Autoregulation Index ◽  
Carbon Dioxide Reactivity ◽  
End Tidal ◽  
Artery Flow

Background Hypercapnia abolishes cerebral autoregulation, but little is known about the interaction between hypercapnia and autoregulation during general anesthesia. With normocapnia, sevoflurane (up to 1.5 minimum alveolar concentration) and propofol do not impair cerebral autoregulation. This study aimed to document the level of hypercapnia required to impair cerebral autoregulation during propofol or sevoflurane anesthesia. Methods Eight healthy subjects received a remifentanil infusion and were anesthetized with propofol (140 microg. kg-1. min-1) and sevoflurane (1.0-1.1% end tidal) in a randomized crossover study. Ventilation was adjusted to achieve incremental increases in arterial carbon dioxide partial pressure (Paco2) until autoregulation was impaired. Cerebral autoregulation was tested by increasing the mean arterial pressure (MAP) from 80 to 100 mmHg with phenylephrine while measuring middle cerebral artery flow velocity by transcranial Doppler. The autoregulation index, which has a value ranging from 0 to 1, representing absent to perfect autoregulation, was calculated, and an autoregulation index of 0.4 or less represented significantly impaired autoregulation. Results The threshold Paco2 to significantly impair cerebral autoregulation ranged from 50 to 66 mmHg. The threshold averaged 56 +/- 4 mmHg (mean +/- SD) during sevoflurane anesthesia and 61 +/- 4 mmHg during propofol anesthesia (P = 0.03). Carbon dioxide reactivity measured at a MAP of 100 mmHg was 30% greater than that at a MAP of 80 mmHg. Conclusions Even mild hypercapnia can significantly impair cerebral autoregulation during general anesthesia. There is a significant difference between propofol anesthesia and sevoflurane anesthesia with respect to the effect of hypercapnia on cerebral autoregulation. This difference occurs at clinically relevant levels of Paco2. When inducing hypercapnia, carbon dioxide reactivity is significantly affected by the MAP.

Assessment of dynamic cerebral autoregulation and cerebral carbon dioxide reactivity during normothermic cardiopulmonary bypass

2014 ◽  
Vol 53 (3) ◽  
pp. 195-203 ◽  
Author(s):  
Ervin E. Ševerdija ◽  
Erik D. Gommer ◽  
Patrick W. Weerwind ◽  
Jos P. H. Reulen ◽  
Werner H. Mess ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Cardiopulmonary Bypass ◽  
Cerebral Autoregulation ◽  
Carbon Dioxide Reactivity ◽  
Dynamic Cerebral Autoregulation
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