Ethanol reduces the minimum alveolar concentration of sevoflurane in rats

A high number of trauma patients are under the influence of alcohol. Since many of them need immediate surgical procedures, it is imperative to be aware of the interaction of alcohol with general anesthesia. To counter challenges that arise from clinical studies, we designed an animal experiment in which 48 adult Wistar rats either received 1 g · kg−1 ethanol, 2 g · kg−1 ethanol or placebo via intraperitoneal application. Subsequently, they were anesthetized with an individual concentration of sevoflurane. The minimum alveolar concentration (MAC) of the different groups was assessed using Dixon’s up-and-down design and isotonic regression methods. The bootstrap estimate of the MAC of sevoflurane in the placebo group was 2.24 vol% (95% CI 1.97–2.94 vol%). In the low dose ethanol group, the bootstrap estimate was 1.65 vol% (95% CI 1.40–1.98 vol%), and in the high dose ethanol group, it was 1.08 vol% (95% CI 0.73–1.42 vol%). We therefore report that intraperitoneal application of 1 g · kg−1 or 2 g · kg−1 ethanol both resulted in a significant reduction of the MAC of sevoflurane in adult Wistar rats: by 26.3% and 51.8% respectively as compared to placebo.

The effect of a ketamine constant rate infusion on cardiovascular variables in sheep anesthetized at the minimum alveolar concentration of sevoflurane that blunts adrenergic responses

OBJECTIVE To evaluate the effect of a constant rate infusion of ketamine on cardiac index (CI) in sheep, as estimated using noninvasive cardiac output (NICO) monitoring by partial carbon dioxide rebreathing, when anesthetized with sevoflurane at the previously determined minimum alveolar concentration that blunts adrenergic responses (MACBAR). ANIMALS 12 healthy Dorset-crossbred adult sheep. PROCEDURES Sheep were anesthetized 2 times in a balanced placebo-controlled crossover design. Anesthesia was induced with sevoflurane delivered via a tight-fitting face mask and maintained at MACBAR. Following induction, sheep received either ketamine (1.5 mg/kg IV, followed by a constant rate infusion of 1.5 mg/kg/h) or an equivalent volume of saline (0.9% NaCl) solution (placebo). After an 8-day washout period, each sheep received the alternate treatment. NICO measurements were performed in triplicate 20 minutes after treatment administration and were converted to CI. Blood samples were collected prior to the start of NICO measurements for analysis of ketamine plasma concentrations. The paired t test was used to compare CI values between groups and the ketamine plasma concentrations with those achieved during the previous study. RESULTS Mean ± SD CI of the ketamine and placebo treatments were 2.69 ± 0.65 and 2.57 ± 0.53 L/min/m2, respectively. No significant difference was found between the 2 treatments. Mean ketamine plasma concentration achieved prior to the NICO measurement was 1.37 ± 0.58 µg/mL, with no significant difference observed between the current and prior study. CLINICAL RELEVANCE Ketamine, at the dose administered, did not significantly increase the CI in sheep when determined by partial carbon dioxide rebreathing.

Perbedaan Pengaruh Sevofluran dan Propofol Terhadap Kadar IL-6 dan Jumlah Neutrofil pada Operasi Kraniotomi

Latar Belakang: Imunitas bawaan adalah lini pertahanan pertama dan mengacu pada mekanisme perlindungan yang ada bahkan sebelum adanya luka / infeksi. Komponen yang dapat digunakan untuk mengetahui perubahan imunitas antara lain sitokin (IL-6) dan neutrofil. Anestesi umum dapat diberikan dengan menggunakan anestesi inhalasi, obat intravena, atau sebagian besar sering kombinasi keduanya. Semua bentuk obat anestesi ini dapat mempengaruhi sistem kekebalan tubuh dan memberikan efek pada imunitas bawaan.Tujuan: Penelitian ini bertujuan untuk mengetahui perbedaan pengaruh sevofluran dan propofol terhadap sistem imun dinilai dari kadar IL-6 dan neutrofil pada operasi bedah saraf.Metode: Dilakukan penelitian eksperimental terhadap 34 subjek (17 subjek kelompok sevofluran dan 17 subjek kelompok propofol) yang menjalani operasi kraniotomi yang memenuhi kriteria penelitian. Kelompok I (17 subjek) menggunakan sevofluran 1 minimum alveolar concentration (MAC) dan kelompok II (17 subjek) menggunakan propofol maintenance infusion 100 μg/kg/menit. Dilakukan pengambilan sampel darah untuk pemeriksaan kadar IL-6 dan neutrofil saat sebelum operasi dan 2 jam setelah insisi operasi. Data dianalisa secara statistik menggunakan Wilcoxon dan Mann-Whitney test, dianggap bermakna bila p < 0,05.Hasil: Pada penelitian ini didapatkan penurunan kadar neutrofil pada kelompok sevofluran sebesar 0,02 ± 7,54 % dibanding kadar awal (berbeda tidak bermakna p= 0,205) sedangkan pada kelompok propofol didapatkan peningkatan kadar neutrofil sebesar 5,07 ± 7,01% dibanding kadar awal (berbeda bermakna p=0,002). Pada perbandingan selisih kedua kelompok didapatkan perbedaan kadar neutrofil yang bermakna (p=0,003). Kadar IL-6 pada kelompok sevofluran didapatkan peningkatan sebesar 4,86 ± 6,87 pg/ml dibanding kadar awal (berbeda bermakna p=0,017) dan pada kelompok propofol juga didapatkan peningkatan sebesar 15,87 ± 16,12 pg/ml dibanding kadar awal (berbeda bermakna p=<0,001). Pada perbandingan selisih kedua kelompok didapatkan perbedaan kadar IL-6 yang bermakna (p=0,009).Kesimpulan: Sevofluran lebih menurunkan kadar IL-6 dan jumlah neutrofil dibandingkan dengan propofol pada operasi kraniotomi.