Comparison of leak fraction between the laryngeal mask airway and endotracheal tube during anesthesia: a single-center retrospective study.

The use of the laryngeal mask airway (LMA), which offers the benefits of ease in insertion and prevention of tracheal damage, is associated with a risk of flow leakage. This study analyzed our extensive database to compare leakage associated with the use of LMA and endotracheal tube (ETT). Adult patients who underwent chest wall, abdominal wall, inguinal region, limb, transurethral, or transvaginal surgery and received either LMA or ETT between January 2007 and March 2020 were included. The leak fraction was calculated as (inspiratory tidal volume-expiratory tidal volume)/(inspiratory tidal volume) × 100% every minute during intraoperative stable positive pressure ventilation. The median leak fraction was calculated for each case. The leak fraction in the LMA group demonstrated a left-skewed distribution with a larger proportion of excessive leak fraction. The leak fraction in the LMA group (median, 7.9%; interquartile range, 4.8-11.4%) was significantly lower than that in the ETT group (median, 9.1%; interquartile range: 5.5-12.4%; P < 0.001). This tendency was consistent across subgroups divided by sex, age, type of surgery, and ventilation mode. We propose that LMA provides leakage comparable to or less than ETT in most cases if stable positive pressure ventilation is achieved.

Quantitative relationship between anteriorization of alpha oscillations and level of general anesthesia.

A typical electroencephalogram (EEG) change induced by general anesthesia is anteriorization-disappearance of occipital alpha oscillations followed by the development of frontal alpha oscillations. Investigating the quantitative relationship between such a specific EEG change and the level of anesthesia has academic and clinical importance. We quantified the degree of anteriorization and investigated its detailed relationship with the level of anesthesia. We acquired 21-electrode EEG data and bispectral index (BIS) values of 50 patients undergoing surgery from before anesthesia induction until after patient arousal. For each epoch of a 10.24-s window with 1-s offsets, we calculated frontal alpha power [Formula: see text], occipital alpha power [Formula: see text], and their difference [Formula: see text] to quantify anteriorization. We calculated Spearman's rank correlation coefficients between these values and the BIS value. We used locally weighted regression to estimate [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] at each BIS value. Thirty-six patients (26 females and 10 males aged 24-85 years) were analyzed. The 95% confidence intervals for the mean of Fisher transformations of Spearman's rank correlation coefficients between [Formula: see text], [Formula: see text], and [Formula: see text] and BIS value were [- 0.68, - 0.26], [0.02, 0.62], and [- 1.11, - 0.91], respectively. The change in [Formula: see text] and [Formula: see text] with BIS value showed different patterns by the type of anesthetic agent, whereas that in [Formula: see text] was more consistent with smaller individual variance. Anteriorization, quantified by the difference between frontal and occipital alpha powers, continuously developed in conjunction with general anesthesia. Quantifying anteriorization may provide an objective indicator of the level of anesthesia.

Ventricular fibrillation during carotid endarterectomy and bailout stenting: a case report.

BACKGROUND: Carotid artery manipulation is not a special technique but reports of intraoperative ventricular fibrillation are rare. The risk of fatal arrhythmias may be hidden behind routine surgical techniques and anesthetic management. We focused on QT prolongation and QT dispersion. CASE PRESENTATION: A 77-year-old man underwent carotid endarterectomy and bailout stenting. Although there were no obvious preoperative risk factors for intraoperative ventricular tachyarrhythmia, ventricular fibrillation (VF) had occurred during a maneuver of the carotid artery under hypercapnia. QTc was prolonged from 317 ms before surgery to 458 ms before the onset of VF. QTc dispersion between leads II and III was also increased to 50 ms. Hypomagnesemia was noted after resuscitation by electrical defibrillation, adrenaline, and noradrenaline. CONCLUSIONS: We considered that the combination of multiple risk factors led to the development of ventricular fibrillation. It should be noted that carotid artery manipulation has the potential to cause arrhythmias.

Prospective evaluation of visual function in patients with ocular diseases after robot-assisted laparoscopic prostatectomy.

OBJECTIVES: To investigate intraocular pressure and visual function in patients with ocular diseases undergoing robot-assisted laparoscopic prostatectomy. METHODS: We carried out a prospective clinical study of patients undergoing robot-assisted laparoscopic prostatectomy for localized prostate cancer at The University of Tokyo Hospital from December 2015 to March 2017. An ophthalmologist measured intraocular pressure, and carried out visual field testing at 0-2 months before and 7 days after robot-assisted laparoscopic prostatectomy. During the surgery, an anesthesiologist measured intraocular pressure at specified time points. RESULTS: A total of 110 patients were enrolled and 98 eligible patients were analyzed; 37 were diagnosed with ocular diseases before robotic-assisted laparoscopic prostatectomy (17 with glaucoma, 20 with other ocular diseases). Intraocular pressure significantly increased during robot-assisted laparoscopic prostatectomy. Transient postoperative visual field defect was detected in 24 eyes of 17 patients, including six patients with ocular diseases at 7 days after surgery. At 3 months after surgery, one of 34 glaucomatous eyes and one of 40 eyes with non-glaucomatous ocular diseases continued to show visual field defect, although visual field defect in the remaining patients recovered to preoperative conditions within 3 months. CONCLUSIONS: Our findings suggest that robot-assisted laparoscopic prostatectomy can be safely carried out in patients with ocular diseases, even those with glaucoma, after precautionary consultation with an ophthalmologist.

Quantitative evaluation of stress in Japanese anesthesiology residents based on heart rate variability and psychological testing.

Clinical anesthesiologists, particularly residents, work in stressful environments. However, evidence-based physiological and psychological tests to evaluate stress are still lacking. In this single-center study of 33 residents, we investigated the relationship between heart rate variability (HRV), which had the potential to screen residents' stress levels using Holter electrocardiography (ECG) and psychological mood as assessed by the Profile of Mood States (POMS) questionnaire. HRV analysis revealed 2 findings. Firstly, standard deviation of the average of 5-min normal-to-normal R-R intervals (SDANN) was significant lower than that of same-aged healthy volunteers (69.3 ± 27.9 vs. 137.0 ± 43.0 ms, P < 0.05), which indicated suppression of autonomic nervous system activity throughout their work. Secondly, at induction of anesthesia, significant higher low frequency/high frequency ratio (LF/HF ratio: 1.326 vs. 0.846; P < 0.05) and lower HF (3326 vs. 5967 ms2; P < 0.05) and lower standard deviation of normal-to-normal R-R intervals (SDNN: 50.5 vs. 79.4 ms; nervous system was suppressed at the induction of anesthesia: expected to be the most stressful period of their work. On the other hand, deviation scores of POMS questionnaire elucidated that all the residents were within normal range of psychological mood, and without any significant diurnal changes with respect to total mood disturbance deviation (TMD) scores (48 vs. 47; P = 0.368). HRV elucidated physiological stress among anesthesiology residents quantitatively by evaluating autonomic nervous activities, especially at induction of anesthesia. These changes in HRV could be observed regardless of psychological mood.

Reliability of cardiac output measurements using LiDCOrapid™ and FloTrac/Vigileo™ across broad ranges of cardiac output values.

Knowing a patient's cardiac output (CO) could contribute to a safe, optimized hemodynamic control during surgery. Precise CO measurements can serve as a guide for resuscitation therapy, catecholamine use, differential diagnosis, and intervention during a hemodynamic crisis. Despite its invasiveness and intermittent nature, the thermodilution technique via a pulmonary artery catheter (PAC) remains the clinical gold standard for CO measurements. LiDCOrapid™ (LiDCO, London, UK) and FloTrac/Vigileo™ (Edwards Lifesciences, Irvine, CA) are less invasive continuous CO monitors that use arterial waveform analysis. Their calculations are based on arterial waveform characteristics and do not require calibration. Here, we evaluated LiDCOrapid™ and FloTrac/Vigileo™ during off-pump coronary artery bypass graft (OPCAB) and living-donor liver transplantation (LDLT) surgery. This observational, single-center study included 21 patients (11 OPCAB and 10 LDLT). We performed simultaneous measurements of CO at fixed sampling points during surgery using both devices (LiDCOrapid™ version 1.04-b222 and FloTrac/Vigileo™ version 3.02). The thermodilution technique via a PAC was used to obtain the benchmark data. LiDCOrapid™ and FloTrac/Vigileo™ were used in an uncalibrated fashion. We analyzed the measured cardiac index using a Bland-Altman analysis (the method of variance estimates recovery), a polar plot method (half-moon method), a 4-quadrant plot and compared the widths of the limits of agreement (LOA) using an F test. One OPCAB patient was excluded because of the use of an intra-aortic balloon pumping during surgery, and 20 patients (10 OPCAB and 10 LDLT) were ultimately analyzed. We obtained 149 triplet measurements with a wide range of cardiac index. For the FloTrac/Vigileo™, the bias and percentage error were -0.44 L/min/m2 and 74.4 %. For the LiDCOrapid™, the bias and percentage error were -0.38 L/min/m2 and 53.5 %. The polar plot method showed an angular bias (FloTrac/Vigileo™ vs. LiDCOrapid™: 6.6° vs. 5.8°, respectively) and radial limits of agreement (-63.9 to 77.1 vs. -41.6 to 53.1). A 4-quadrant plot was used to obtain concordance rates (FloTrac/Vigileo™ vs. PAC and LiDCOrapid™ vs. PAC: 84.0 and 92.4 %, respectively). We could compare CO measurement devices across broad ranges of CO and SVR using LDLT and OPCAB surgical patients. An F test revealed no significant difference in the widths of the LoA for both devices when sample sizes capable of detecting a more than two-fold difference were used. We found that both devices tended to underestimate the calculated CIs when the CIs were relatively high. These proportional bias produced large percentage errors in the present study.

[Anesthetic management for emergency laparotomy in an adult patient with Eisenmenger syndrome: a case report].

There are few clinical reports concerning anesthetic management for patients with Eisenmenger syndrome requiring non-cardiac surgery. The risk of morbidity and mortality associated with non-cardiac surgery in patients with Eisenmenger syndrome is considerable. During anesthetic management for these patients, careful circulatory and respiratory managements to avoid several factors related to surgery and anesthesia that can potentially increase right to left shunt flow are required. Therefore, it is very important to maintain cardiac output to prevent a decrease in systemic vascular resistance and an increase in pulmonary vascular resistance. For this purpose, combination of intravenous administration of inotropes such as milrinone and dobutamine, and vasopressors such as norepinephrine, might have clinical efficacy. Here we describe an anesthetic management for a 50-year-old woman with a ventricular septal defect and Eisenmenger syndrome undergoing emergency laparotomy. We considered that sufficient fluid therapy and adequate administration of inotropes and vasopressors, based on strict hemodynamic assessment using direct arterial and central venous pressure monitoring, arterial blood gas analysis, and transesophageal echocardiography during general anesthesia, might have contributed to the uneventful perioperative course of the patient.