Brazilian consensus on anesthetic depth monitoring

Ti3C2Tx-rGO-chitosan-based microcatheter sensor for real-time continuous monitoring of propofol: toward improved anesthetic management

We are aiming to develop an electrochemical microcatheter sensor for the detection and real-time continuous monitoring of propofol (PPF), which is an anesthetic drug majorly used during medical treatment. This proposed microcatheter-based sensing strategy meets the challenge of real-time periodic and continuous monitoring of propofol by using d-Ti3C2Tx-rGO-chi-modified carbon paste microcatheter sensor transducer. The sensing methodology relies on voltammetry and chronoamperometry transduction methods. The reusable microcatheter sensor was fabricated by embedding the three electrodes into a few millimeters-wide Teflon tube. The nanocomposite was characterized using advanced analytical instruments such as XRD, FE-SEM, EDX, Raman spectroscopy, and XPS. Further, electrode interfacial properties were characterized with voltammetry and electrochemical impedance spectroscopy. The electroanalytical performance of the modified microcatheter sensor was tested for the detection of PPF in phosphate buffer by using chronoamperometry with a wide linear range of 5 to 110 µM (at an applied potential of 0.3 V vs. Ag/AgCl). The sensor's practical potency was confirmed in human serum with a dynamic linear range of 10 to 130 µM. The sensor exhibited a good limit of detection values in phosphate buffer (2 µM) and natural human plasma (4 µM). The new sensor displays different dimensions of information while displaying high sensitivity, selectivity, and long-term stability. The outstanding analytical performance of the developed sensor holds considerable promise for the continuous monitoring of propofol, its effective management, and optimization of the doses in the patient's body.

Effects of small-dose remifentanil combined with index of consciousness monitoring on gastroscopic polypectomy: a prospective, randomized, single-blinded trial

BACKGROUND

With the development of painless diagnosis and treatment, remifentanil, a synthetic opioid agonist, is increasingly used in gastroscopy for its rapid, short-term, and potent analgesic effect. However, the dosage of remifentanil used in endoscopy is unclear. Index of consciousness (IOC) is a new anesthesia depth-monitoring indicator that can be divided into index of consciousness 1 (IOC₁) and index of consciousness 2 (IOC₂); IOC₁ is used for estimating a patient's sedation state, whereas IOC₂ reflects analgesic depth. We hypothesized that combining with IOC₁ and IOC₂ monitoring may be helpful to identify an optimal remifentanil dosage in gastroscopic polypectomy.

METHODS

One hundred twenty patients scheduled for gastroscopic polypectomy were enrolled and were randomly assigned to remifentanil 2 ng/mL (group R2), 4 ng/mL (group R4), or 6 ng/mL (group R6), and 40 cases were in each group. During the anesthesia period, remifentanil was kept at the initial given concentration but propofol was adjusted according to IOC₁. The primary outcomes were the dosage of propofol and remifentanil. The secondary outcomes were the variety of IOC₁ and IOC₂, patients' awakening time, and peri-operative adverse reactions such as hypotension, hypertension, bradycardia, tachycardia, body movements, hypoxemia, therapy interruption, nausea, vomiting, aspiration, and intra-operative awareness.

RESULTS

With the increasing dosage of remifentanil, the propofol dosage and patients' awakening time decreased significantly, the morbidity of hypertension and body movements also declined, but the incidence of hypotension, bradycardia, and hypoxemia rose. In group R2, the value of IOC₂ remained above 50 during the treatment. However, IOC₂ dropped to below 30 at the beginning of the gastroscopy in group R6, and there was statistical difference in hypoxemia between groups R2 and R6 (P <0.05).

CONCLUSIONS

With the help of IOC monitoring, we found that a target concentration of remifentanil 4 ng/mL is comparatively ideal in patients under gastroscopic polypectomy.

TRIAL REGISTRATION

Chinese Clinical Trial Register: ChiCTR-OOD-16009489 , on October 19, 2016.