Possible role of QRS duration in the right ventricle as a perioperative monitoring parameter for right ventricular function: a prospective cohort analysis in robotic mitral valve surgery.

Background: The clinical importance of the right ventricle (RV) has recently been recognized; however, assessing its function during cardiac surgery remains challenging owing to its complex anatomy. A temporary transvenous pacing catheter is a useful tool in the small surgical field of minimally invasive cardiac surgery, and an electrocardiogram recorded through the catheter is composed of the direct electrophysiological activity of the RV. Therefore, we hypothesized that QRS duration in the RV (QRSRV) could be a useful monitoring parameter for perioperative RV function. Methods: We conducted a prospective cohort analysis involving adult patients undergoing robotic mitral valve repair. A bipolar pacing catheter was inserted using x-ray fluoroscopy, and the QRSRV duration was assessed at four time points: preoperative baseline, during one-lung ventilation, after weaning from cardiopulmonary bypass, and before the end of surgery. At the same time points, right ventricular fractional area change (RVFAC) measured by transesophageal echocardiography and QRS duration at V5 lead of the body surface electrocardiogram (QRSV5) were also evaluated. Results: In the 94 patients analyzed, QRSRV duration was significantly prolonged during robotic mitral valve repair (p = 0.0009), whereas no significant intraoperative changes in RVFAC were observed (p = 0.2). By contrast, QRSV5 duration was significantly shortened during surgery (p < 0.00001). Multilinear regression showed a significant correlation of QRSRV duration with RVFAC (p = 0.00006), but not with central venous pressure (p = 0.9), or left ventricular ejection fraction (p = 0.3). When patients were divided into two groups by postoperative QRSRV > 100 or ≤100 ms, 25 patients (26.6%) exhibited the prolonged QRSRV duration, and the mean increase in the postoperative QRSRV from preoperative baseline was 12 ms (p = 0.001), which was only 0.6 ms in patients with QRSRV ≤ 100 ms (p = 0.6). Cox regression analysis showed that prolonged postoperative QRSRV duration was the only significant parameter associated with a longer ICU stay after surgery (p = 0.02; hazard ratio, 0.55). Conclusion: Our data suggest that QRSRV duration is a useful parameter for monitoring the RV during cardiac surgery, possibly better than a commonly used echocardiographic parameter, RVFAC. An electrophysiological assessment by QRSRV duration could be a practical tool for the complex anatomy of the RV, especially with limited modalities in perioperative settings.

Thoracic epidural analgesia prolongs postoperative QT interval on electrocardiogram in major non-cardiac surgery: a randomized comparison and a prospective cohort analysis.

Introduction: Prolongation of QT interval on electrocardiogram can be associated with perioperative lethal arrhythmia. Epidural analgesia is a commonly used modality to relieve surgical pain by blocking sensory nerves, which also blocks the autonomic nervous system and can affect QT interval. Since patient monitoring becomes much less frequent after surgery than intraoperative period, we investigated the effects of epidural analgesia on postoperative QT interval with a randomized clinical trial and a prospective cohort study. Methods: In a randomized study, we assigned 60 patients undergoing thoracic epidural analgesia to an epidural analgesia or no-epidural analgesia group, in which 3 ml/h of 0.25% epidural levobupivacaine (7.5 mg/h) was administered only in the epidural analgesia group during surgery. The primary outcome was the postoperative heart rate-corrected QT interval. In a prospective cohort study, patients were assigned to receive 5 ml/h epidural levobupivacaine (12.5 mg/h). The plasma concentration of levobupivacaine was measured using liquid chromatography-mass spectrometry. Results: The median postoperative corrected QT interval interval with 3 ml/h epidural levobupivacaine was significantly longer than that without epidural analgesia. Using multiple regression analysis for the factors known to affect postoperative corrected QT interval interval, epidural analgesia was found to be an independent variable for prolongation, and the mean difference of the corrected QT interval interval with or without epidural analgesia was 23 ms after adjustment. The median plasma concentration of levobupivacaine at the end of surgery was 164 ng/ml with 3 ml/h epidural levobupivacaine, and the correlation coefficient to the postoperative corrected QT interval interval was 0.14, showing a not significant correlation. A prospective cohort study showed that 5 ml/h epidural levobupivacaine significantly prolonged postoperative corrected QT interval interval compared to preoperative baseline. The median plasma concentration of levobupivacaine was 166 ng/ml with 5 ml/h, the correlation coefficient of which showed no significant correlation. Conclusion: Thoracic epidural analgesia could enhance postoperative corrected QT interval prolongation after general anesthesia. The mechanism is possibly caused by blocking neighboring or part of the cardiac sympathetic nerves, rather than by systemic effects of epidurally administered levobupivacaine. Clinical trial number: UMIN000013347 for the randomized study and UMIN000041518 for the prospective cohort study, which were registered at University hospital Medical Information Network Center.

Symptomatic absorption of normal saline during transurethral resection of the prostate: a case report.

BACKGROUND: Transurethral resection of the prostate (TUR-P) could incidentally cause hyponatremia, known as TUR syndrome due to intravascular absorption of non-electrolytic irrigation fluid. Recently, normal saline has been used as an irrigation fluid in a new system named TURis (TUR in saline) to prevent TUR syndrome. However, rapid massive absorption of normal saline can also cause other systemic adverse events. CASE PRESENTATION: A 71-year-old man underwent TURis for benign prostatic hyperplasia under spinal anesthesia. The patient lost consciousness which led upper airway obstruction and hypoxia 30 min after the surgery began. Blood gas test indicated hyperchloremic metabolic acidosis. While vasoactive agents were ineffective, the administration of bicarbonate significantly improved the symptoms and restored blood pressure. CONCLUSION: We experienced a case of hyperchloremic metabolic acidosis with decreased level of consciousness and hypotension during TURis. Administration of bicarbonate, but not phenylephrine, was effective for recovering blood pressure.

Lipid emulsion facilitates reversal from volatile anesthetics in a rodent model.

BACKGROUND: Lipid emulsion infusion is a first-line therapy against the toxicity of local anesthetics and is a potential treatment for other drug overdoses, especially for highly lipophilic drugs. Considering the lipophilic property of volatile anesthetics, we hypothesized that lipid emulsion could reverse general anesthesia. METHODS: Using adult rats, we tested the effect of lipid emulsion infusion on time to emergence after discontinuation of sevoflurane and isoflurane, and further evaluated restoration of righting reflex under continuous sevoflurane anesthesia. Electroencephalogram during lipid emulsion infusion was also investigated under continuous sevoflurane inhalation. The effect of lipid emulsion on sevoflurane-induced respiratory and hemodynamic depressions was evaluated by measuring respiratory rate, PaCO2 (arterial partial pressure of CO2), blood pressure, and heart rate. The binding property of lipid emulsion on sevoflurane and isoflurane was assessed using in vitro setting with a conical flask. RESULTS: Lipid emulsion infusion significantly decreased time to emergence from sevoflurane anesthesia (131 ± 53 vs. 237 ± 69 s) and restored righting reflex during continuous sevoflurane inhalation, by comparing normal saline infusion. Consistent with the behavioral findings, the electroencephalogram under continuous sevoflurane showed decreased power of the δ bands at 5 min after the initiation of lipid emulsion infusion. In addition to reversing hypnosis, lipid emulsion recovered respiratory as well as hemodynamic depressions induced by sevoflurane. Decreased time to emergence was observed also in isoflurane anesthesia (203 ± 111 vs. 314 ± 154 s). To investigate the binding mechanism of lipid emulsion infusion, in vitro experiments revealed significantly decreased anesthetic concentrations of sevoflurane and isoflurane by mixing with lipid emulsion. CONCLUSIONS: Lipid emulsion facilitated reversal from volatile anesthetics, as shown by several parameters. As lipid emulsion could bind to volatile anesthetics and simply decrease their effects, our findings suggest that lipid emulsion is a potentially useful agent to reverse general anesthesia.

Left Ventricular Hypertrophy Increases Susceptibility to Bupivacaine-induced Cardiotoxicity through Overexpression of Transient Receptor Potential Canonical Channels in Rats.

BACKGROUND: Local anesthetics, particularly potent long acting ones such as bupivacaine, can cause cardiotoxicity by inhibiting sodium ion channels; however, the impact of left ventricular hypertrophy on the cardiotoxicity and the underlying mechanisms remain undetermined. Transient receptor potential canonical (TRPC) channels are upregulated in left ventricular hypertrophy. Some transient receptor potential channel subtypes have been reported to pass relatively large cations, including protonated local anesthetics; this is known as the "pore phenomenon." The authors hypothesized that bupivacaine-induced cardiotoxicity is more severe in left ventricular hypertrophy due to upregulated TRPC channels. METHODS: The authors used a modified transverse aortic constriction model as a left ventricular hypertrophy. Cardiotoxicity caused by bupivacaine was compared between sham and aortic constriction male rats, and the underlying mechanisms were investigated by recording sodium ion channel currents and immunocytochemistry of TRPC protein in cardiomyocytes. RESULTS: The time to cardiac arrest by bupivacaine was shorter in aortic constriction rats (n =11) than in sham rats (n = 12) (mean ± SD, 1,302 ± 324 s vs. 1,034 ± 211 s; P = 0.030), regardless of its lower plasma concentration. The half-maximal inhibitory concentrations of bupivacaine toward sodium ion currents were 4.5 and 4.3 µM, which decreased to 3.9 and 2.6 µM in sham and aortic constriction rats, respectively, upon coapplication of 1-oleoyl-2-acetyl-sn-glycerol, a TRPC3 channel activator. In both groups, sodium ion currents were unaffected by QX-314, a positively charged lidocaine derivative, that hardly permeates the cell membrane, but was significantly decreased with QX-314 and 1-oleoyl-2-acetyl-sn-glycerol coapplication (sham: 79 ± 10% of control; P = 0.004; aortic constriction: 47± 27% of control; P = 0.020; n = 5 cells per group). Effects of 1-oleoyl-2-acetyl-sn-glycerol were antagonized by a specific TRPC3 channel inhibitor. CONCLUSIONS: Left ventricular hypertrophy exacerbated bupivacaine-induced cardiotoxicity, which could be a consequence of the "pore phenomenon" of TRPC3 channels upregulated in left ventricular hypertrophy.

Comparison between hemodynamic effects of propofol and thiopental during general anesthesia induction with remifentanil infusion: a double-blind, age-stratified, randomized study.

PURPOSE: Propofol is commonly used with remifentanil for induction of general anesthesia (GA); however, it often leads to hypotension. Intraoperative hypotension is associated with postoperative adverse events. By contrast, thiopental has less negative inotropic effects on hemodynamics compared to propofol, which could be suitable to prevent hypotension during GA induction. In the present age-stratified, randomized, assessor-blinded study, using the ClearSight® system, we compared the hemodynamic effects of propofol and thiopental during GA induction under remifentanil infusion in non-cardiac surgery. METHODS: Patients were divided into young (20-40 year), middle (41-70 year), and elderly (> 70 year) groups (n = 20, each group). General anesthesia was induced with remifentanil 0.3 µg/kg/min, followed by propofol (2.0, 1.5, and 1.2 mg/kg) or thiopental (5.0, 4.0, and 3.0 mg/kg) in the young, middle, and elderly groups, respectively. The primary outcome was the difference in the decrease in mean arterial blood pressure between patients receiving propofol and thiopental in each age group. The secondary outcomes included other hemodynamic parameters and minimal bispectral index values measured up to 10 min after tracheal intubation. RESULTS: The decrease in mean arterial blood pressure was greater in patients receiving propofol than those receiving thiopental (- 45.4 vs - 26.6 mmHg and - 45.7 vs - 28.9 mmHg, P = 0.003 and 0.007, respectively), whereas no significant difference was observed in the young age group (P = 0.96). CONCLUSIONS: Thiopental is a more suitable agent than propofol for avoiding hypotension during GA induction under remifentanil infusion in the middle and elderly patients.