Effects of sevoflurane versus propofol on cerebrovascular reactivity to carbon dioxide during laparoscopic surgery

Vascular and neuronal effects of general anesthesia on the brain: An fMRI study

BACKGROUND AND PURPOSE

A number of functional magnetic resonance imaging (fMRI) studies rely on application of anesthetic agents during scanning that can modulate and complicate interpretation of the measured hemodynamic blood oxygenation level-dependent (BOLD) response. The purpose of the present study was to investigate the effect of general anesthesia on two main components of BOLD signal including neuronal activity and vascular response.

METHODS

Breath-holding (BH) fMRI was conducted in wakefulness and under anesthesia states in 9 patients with drug-resistant epilepsy who needed to get scanned under anesthesia during laser interstitial thermal therapy. BOLD and BOLD cerebrovascular reactivity (BOLD-CVR) maps were compared using t-test between two states to assess the effect of anesthesia on neuronal activity and vascular factors (p < .05).

RESULTS

Overall, our findings revealed an increase in BOLD-CVR and decrease in BOLD response under anesthesia in several brain regions. The results proposed that the modulatory mechanism of anesthetics on neuronal and vascular components of BOLD signal may work in different ways.

CONCLUSION

This experiment for the first human study showed that anesthesia may play an important role in dissociation between neuronal and vascular responses contributed to hemodynamic BOLD signal using BH fMRI imaging that may assist the implication of general anesthesia and interpretation of outcomes in clinical setting.

Effects of ultrasound-guided stellate ganglion block on the balance of the supply and demand of cerebral oxygen during permissive hypercapnia in patients undergoing shoulder arthroscopy in beach chair position

OBJECTIVE

To investigate the effects of ultrasound-guided stellate ganglion block (SGB) on the supply and demand balance of cerebral oxygen in patients with permissive hypercapnia (PHC) undergoing shoulder arthroscopy in a beach chair position (BCP).

METHOD

In this prospective study, a total of 86 patients who had shoulder arthroscopy were enrolled and divided into the stellate ganglion block group (SG group, n=43) and the control group (CN group, n=43) using a random number table method. Ultrasound-guided SGB was performed on patients' operation side at the 6th cervical vertebra (C6) anterior transverse tubercle level. Patients in the SG group were injected with 6ml mixture of 0.25% ropivacaine hydrochloride and 1% lidocaine hydrochloride, and those in the CN group with an equal amount of 0.9% normal saline (NS). The patients of both groups were placed in BCP for shoulder arthroscopy, and rapid induction of endotracheal intubation was performed for assisted or mechanical ventilation. Ventilation strategy was adjusted to gradually increase pulmonary end-tidal CO₂ (P_ETCO₂) during surgery. The rSO₂ levels of patients in both groups were recorded 10 min after being placed in supine position in the operation room (T0), 10 min after SGB (T1), 10 min after anesthesia induction in supine position (T2), 10 min after anesthesia induction in beach chair position (T3), 30 min after P_ETCO₂ was stabilized at 35 to 40 mmHg (T4) during surgery, and 30 min after P_ETCO₂ was stabilized at 45 to 50 mmHg (T5), respectively. The cerebral oxygen metabolic measures, including saturation of jugular bulb venous oxygen (SjvO₂), difference in artery-jugular venous oxygen content (DajvO₂) and cerebral oxygen extraction rate (CERO₂) of patients in the two groups at the time point mentioned above were compared. Hemodynamic parameters including arterial carbon dioxide partial pressure (PaCO₂), mean arterial pressure (MAP), heart rate (HR) and Saturation of Pulse Oxygen (SpO₂) were recorded. Cerebral desaturation episodes, nausea, vomiting and the use of vasoactive drugs during surgery were also recorded. The Mini-Mental State Examination score (MMSE) was recorded 1 day before and after surgery.

RESULTS

There was no significant difference in the comparison of SjvO₂, Da-jvO₂, CERO₂, PaCO₂, MAP, HR and SpO₂ between the two groups at T0-T5 (P>0.05); no significant differences were found in intra-group comparison of SjvO₂, Da-jvO₂, CERO₂ at T0-T4 (P>0.05); the level of SjvO₂ at T5 was higher than that at T4, and the levels of Da-jvO₂ and CERO₂ at T5 were markedly lower than those at T4 (P<0.05). No significant differences were found in the inter-group comparison of MAP, HR and SpO₂ at T0-T5 (P>0.05), while PaCO₂ was significantly higher at T4 than that at T5 (P<0.05). The rSO₂ levels of patients in both groups significantly decreased at T3, as compared with those at T0 (P<0.05); the rSO₂ levels markedly increased at T5 than those at T4 (P<0.05); and the rSO₂ levels showed more significant increase in SGB group than those in the CN group as the level of P_ETCO₂ rose.

CONCLUSION

Permissive hypercapnia resulting from proper ventilation can significantly increase the rSO₂ levels in patients who undergo shoulder arthroscopy in BCP, the effect of which was enhanced by SGB on patients' operation side to maintain well-balanced demand and supply of cerebral oxygen. (China Clinical Trial Registry, registration number ChiCTR2000033385, https://www.chictr.org.cn).

Association between the reactivity of local cerebral oxygen saturation after hypo-to-hypercapnic tests and delirium after abdominal surgery in older adults: A prospective study

OBJECTIVE

This study aimed to investigate the correlation between changes in regional cerebral oxygen saturation (rSO2) and postoperative delirium in older adults undergoing major abdominal surgery.

MATERIALS AND METHODS

This prospective study enrolled older adults scheduled for elective major abdominal surgery at the Second Affiliated Hospital of Anhui Medical University from August 2021 to January 2022. The change in rSO2 from baseline was determined using the hypo-to-hypercapnic test. The main study outcome was the occurrence of postoperative delirium.

RESULTS

A total of 101 participants were included for analysis, of whom 16 (15.8%) developed postoperative delirium. Compared with non-delirium participants, the mean arterial pressure and heart rate were not significantly different in the postoperative delirium group at T0, T1, T2, T3, T4, and T6 (all P_interaction > 0.05), but the delirium group had lower pH, lower PaO2, and higher lactate levels at T4, T5, and T6 (all P_interaction < 0.05). rSO2 at T0, T1, T2, T3, T4, and T6 was 69.0 (63.2-75.2), 70.7 ± 7.3, 68.2 ± 7.5, 72.1 ± 8.0, 69.9 ± 7.8, 67.4 ± 7.2, and 71.7 ± 8.1, respectively. The postoperative change in rSO2 during the hypercapnia test (TΔrSO2%) was 6.62 (5.31-9.36). Multivariable analysis showed that the Cumulative Illness Rating Scale (odd ratio, OR = 1.89, 95% confidence interval, CI: 1.10-3.25, P = 0.021), preoperative albumin levels (OR = 0.67, 95% CI: 0.48-0.94, P = 0.022), rSO2 at T4 (OR = 0.61, 95% CI: 0.41-0.89, P = 0.010), and postoperative TΔrSO2% (OR = 0.80, 95% CI: 0.66-0.98, P = 0.028) were independently associated with postoperative delirium in older adults undergoing elective abdominal surgery.

CONCLUSION

The rSO2 measured at T4 and postoperative TΔrSO2% were independently associated with postoperative delirium in older adults undergoing elective abdominal surgery.

Effect of flurbiprofen axetil on postoperative delirium for elderly patients

OBJECTIVES

Proinflammatory cytokines triggered by surgery and postoperative pain are major causes of postoperative delirium (POD). This study investigated the effects of flurbiprofen axetil on POD when used for postoperative analgesia after major noncardiac surgery in elderly patients.

METHODS

Patients over 65 years old were randomly divided into two groups: the sufentanil group (S group), in which 150 μg of sufentanil was used in the patient-controlled analgesia (PCA) pump for 3 days; the sufentanil combined with flurbiprofen axetil group (SF group), in which 150 μg of sufentanil was combined with 300 mg of flurbiprofen axetil in the PCA pump for 3 days. The Confusion Assessment Method scale was used for POD evaluation. The pain intensity, side effects, and risk factors (age, gender, surgical position, and category of surgery) for POD were evaluated.

RESULTS

Ultimately, 140 patients were included. The overall incidence of POD was not significantly different between the S and SF groups. The incidence of POD was significantly lower in the SF group than in the S group among patients over 70 years (5.1% vs. 20.7%, p = 0.045, odds ratio = 0.146, 95% confidence interval = 0.020-1.041). The incidence of POD was no difference in patients classified by the category of surgery, surgical position, or gender between groups. Sufentanil and flurbiprofen axetil in the PCA pump was completely used within 72 hr. The pain intensity, consumed sufentanil dosage of the PCA, and the side effects was not different between groups.

CONCLUSIONS

Flurbiprofen axetil might reduce POD in patients over 70 years undergoing major noncardiac surgery.

Anesthetic effect of propofol combined with remifentanil or sevoflurane anesthesia on patients undergoing radical gastrectomy

Anesthetic effect of propofol combined with remifentanil or sevoflurane intravenous anesthesia on patients undergoing radical gastrectomy was evaluated. The clinical data of 516 cancer patients who received radical gastrectomy in the First Bethune Hospital of Jilin University between January 2011 and December 2017 were retrospectively analyzed. In total 203 patients with propofol combined with remifentanil anesthesia were used as group A, and 313 patients with propofol combined with sevoflurane anesthesia as group B. The changes of respiration and circulation were analyzed at the time of entering the operating room (t0), the beginning of the operation (t1), 10 min after the beginning of the operation (t2) and 10 min after operation (t3). The onset time of anesthesia, the total time of operation, the time of waking up after operation and the time of leaving the operating room were analyzed. The effects of sedation and amnesia were evaluated, and the occurrence of adverse reactions were recorded. The inhibition of circulation and respiration was more obvious at t1 and t2 in group A when compared to group B (P<0.05), and the respiration and circulation in group B was more stable than that in group A (P<0.001). Patients' sedation scores in group A were lower than those in group B, and the difference was statistically significant (P<0.05); there were 56 (27.59%) patients and 30 (9.58%) patients with postoperative pain in group A and group B, respectively (P<0.001). The application of propofol combined with sevoflurane in the anesthesia of patients undergoing radical gastrectomy can make the respiration and circulation more stable, and reduce the incidence of postoperative pain and adverse reactions.

Photoacoustic microscopy of obesity-induced cerebrovascular alterations

Cerebral small vessel disease has been linked to cognitive, psychiatric and physical disabilities, especially in the elderly. However, the underlying pathophysiology remains incompletely understood, largely due to the limited accessibility of these small vessels in the live brain. Here, we report an intravital imaging and analysis platform for high-resolution, quantitative and comprehensive characterization of pathological alterations in the mouse cerebral microvasculature. By exploiting multi-parametric photoacoustic microscopy (PAM), microvascular structure, blood perfusion, oxygenation and flow were imaged in the awake brain. With the aid of vessel segmentation, these structural and functional parameters were extracted at the single-microvessel level, from which vascular density, tortuosity, wall shear stress, resistance and associated cerebral oxygen extraction fraction and metabolism were also quantified. With the use of vasodilatory stimulus, multifaceted cerebrovascular reactivity (CVR) was characterized in vivo. By extending the classic Evans blue assay to in vivo, permeability of the blood-brain barrier (BBB) was dynamically evaluated. The utility of this enabling technique was examined by studying cerebrovascular alterations in an established mouse model of high-fat diet-induced obesity. Our results revealed increased vascular density, reduced arterial flow, enhanced oxygen extraction, impaired BBB integrity, and increased multifaceted CVR in the obese brain. Interestingly, the 'counterintuitive' increase of CVR was supported by the elevated active endothelial nitric oxide synthase in the obese mouse. Providing comprehensive and quantitative insights into cerebral microvessels and their responses under pathological conditions, this technique opens a new door to mechanistic studies of the cerebral small vessel disease and its implications in neurodegeneration and stroke.