Changes in the corrected carotid flow time can predict spinal anesthesia-induced hypotension in patients undergoing cesarean delivery: an observational study.

PURPOSE: Spinal anesthesia is a standard technique for cesarean delivery; however, it possesses a risk of hypotension. We hypothesised that the changes in the corrected flow time induced by the Trendelenburg position could predict the incidence of hypotension after spinal anesthesia for cesarean delivery. METHODS: Patients undergoing elective cesarean delivery under spinal anesthesia were enrolled. Before anesthesia induction, corrected flow time was measured in the supine and Trendelenburg positions (FTc-1 and FTc-2, respectively). Additionally, a percent change in corrected flow time induced by the Trendelenburg position was defined as ΔFTc. The primary endpoint was to investigate the ability of ΔFTc to predict the incidence of spinal anesthesia-induced hypotension until delivery. The receiver operating characteristics curves to assess the ability of FTc-1, FTc-2, and ΔFTc to predict the incidence of hypotension were generated. RESULTS: Finally, 40 patients were included, and of those, 26 (65%) developed spinal anesthesia-induced hypotension. The areas under the curve for FTc-1, FTc-2, and ΔFTc were 0.591 (95% CI: 0.424 to 0.743) (P = 0.380), 0.742 (95% CI: 0.579 to 0.867) (P = 0.004), and 0.882 (95% CI: 0.740 to 0.962) (P < 0.001) respectively, indicating ΔFTc as the best predictor among these three parameters. The best threshold for ΔFTc was 6.4% (sensitivity: 80.8% (95% CI: 53.8 to 96.2), specificity: 85.7% (95% CI: 42.9 to 100.0)). CONCLUSIONS: This study demonstrated that changes in the corrected carotid flow time induced by the Trendelenburg position could serve as a good predictor of spinal anesthesia-induced hypotension for cesarean delivery.

Diagnosis of unicuspid aortic valve after loss of consciousness during cesarean section: A case report.

Loss of consciousness is a rare but potentially serious complication of delivery by cesarean section under spinal anesthesia. Here, we report the case of a pregnant woman with unicuspid aortic valve that was incidentally diagnosed during aortic valve replacement after transient loss of consciousness during cesarean section.

Non-invasive continuous blood pressure monitoring using the ClearSight system for pregnant women at high risks of post-partum hemorrhage: comparison with invasive blood pressure monitoring during cesarean section.

OBJECTIVE: This study aimed to investigate the accuracy and precision of continuous, non-invasive blood pressure obtained using the ClearSight system by comparing it with invasive arterial blood pressure, and to assess the hemodynamic changes using invasive methods and the ClearSight system in patients undergoing cesarean section. METHODS: Arterial pressure was measured invasively with an intra-arterial catheter and non-invasively using the ClearSight system during cesarean section in patients with placenta previa or placenta accreta. Blood pressure measurements obtained using these two means were then compared. RESULTS: Total 1,277 blood pressure measurement pairs were collected from 21 patients. Under Bland-Altman analysis, the ClearSight system demonstrated an acceptable accuracy with a bias and standard deviation of 8.8±13.4 mmHg for systolic blood pressure, -6.3±7.1 mmHg for diastolic blood pressure, and -2.7±8.0 mmHg for median blood pressure. Cardiac index levels were significantly elevated during fetal delivery and 5 minutes after placental removal, and systemic vascular resistance index levels were significantly decreased during fetal delivery and 40 minutes after placental removal. CONCLUSION: In patients undergoing cesarean section, the ClearSight system showed excellent accuracy and precision compared to that of the currently used invasive monitoring system.

Validation of Continuous Noninvasive Blood Pressure Monitoring Using Error Grid Analysis.

BACKGROUND: Error grid analysis was recently proposed to compare blood pressure obtained by 2 measurement methods. This study aimed to compare continuous noninvasive blood pressure (CNBP) with invasive blood pressure (IBP) using the error grid analysis and investigate the confounding risk factors attributable to the differences between CNBP and IBP. METHODS: Sixty adult patients undergoing general anesthesia were prospectively enrolled. Simultaneous comparative data regarding CNBP and IBP were collected. The Bland-Altman analysis was conducted to compare CNBP and IBP for systolic blood pressure (SBP) and mean blood pressure (MBP; acceptable accuracy: mean bias <5 mm Hg; standard deviation <8 mm Hg). The clinical relevance of the discrepancies between CNBP and IBP was evaluated by the error grid analysis, which classifies the differences into 5 zones from "no risk" (A) to "dangerous risk" (E). Additionally, an ordinal logistic regression analysis was performed to evaluate the relationship between the risk zones for MBP, classified by the error grid analysis and covariates of interest. RESULTS: A total of 10,663 pairs of CNBP/IBP were finally analyzed. The Bland-Altman analysis showed an acceptable accuracy with a bias of -3.3 ± 5.6 mm Hg for MBP but a poor accuracy with a bias of 5.4 ± 10.5 mm Hg for SBP. The error grid analysis showed the proportions of zones A to E as 96.7%, 3.2%, 0.1%, 0%, and 0% for SBP, respectively, and 72.0%, 27.9%, 0.1%, 0%, and 0% for MBP, respectively. The finger cuff missed 23.9% of epochs when SBP <90 mm Hg and 55.3% of epochs when MBP <65 mm Hg. The ordinal logistic regression analysis revealed that older age (adjusted odds ratio for decade: 1.54, 95% confidence interval [CI], 1.15-2.08; P = .004) and length of time from the initiation of finger cuff inflation (adjusted odds ratio for 60 minutes: 1.40, 95% CI, 1.13-1.73; P = .002) were significant factors of being in a more dangerous zone of the error grid. CONCLUSIONS: The error grid analysis revealed the larger clinical discrepancy between CNBP and IBP in MBP compared with that in SBP. Old age and longer finger cuff inflation time were significant factors of being in a more dangerous zone of the error grid, which could affect the hemodynamic management during surgery.

Changes in corrected carotid flow time induced by recruitment maneuver predict fluid responsiveness in patients undergoing general anesthesia.

Non-invasive methods to assess patients' fluid responsiveness during lung-protective ventilation are needed. We hypothesized changes in the corrected carotid flow time induced by the recruitment maneuver predict fluid responsiveness under general anesthesia. Thirty patients undergoing general anesthesia in the supine position were prospectively enrolled. The study protocol was conducted when the patient was hemodynamically stable during surgery. Flow time was measured on Doppler images of the common carotid artery. Carotid flow time, heart rate, stroke volume, stroke volume variation, and pulse pressure variation were recorded before and after a recruitment maneuver at a continuous airway pressure of 30 cmH2O for 30 s, and before and after volume expansion with 250 mL for 10 min. Patients were defined as fluid responders if the increase in stroke volume was > 10% after volume expansion. Twenty patients (67%) were fluid responders. All Doppler images for carotid flow time were obtained within 30 s. Changes in the corrected flow time accurately predicted fluid responsiveness (area under the curve: 0.82, 95% confidence interval [CI] 0.64-0.94, p = 0.002). The optimal threshold for changes in the corrected flow time was - 11.7% with a sensitivity of 95.0% (95% CI 75.1-99.9%) and a specificity of 80.0% (95% CI 44.4-97.5%). The gray-zone of changes in the corrected flow time was from - 25.1 to - 12.2% and included 12 patients (40%). Changes in the corrected carotid flow time were a useful, technically easy-to-perform, and non-invasive method to predict fluid responsiveness without a need for hemodynamic monitoring or arterial cannulation.

Participation of the descending noradrenergic inhibitory system in the anti-hyperalgesic effect of acetaminophen in a rat model of inflammation.

AIMS: This study investigated the relationship between the analgesic efficacy of acetaminophen and the descending noradrenergic systems using rodent models of inflammatory pain. MAIN METHODS: Inflammatory pain models were established by carrageenan injection into rats' paws. The models were defined as acute (4 h after carrageenan injection), subacute (24 h after carrageenan injection), and late (1 week after carrageenan injection) phase. To evaluate intravenous acetaminophen treatment, the withdrawal threshold to mechanical stimuli was assessed simultaneously with in vivo microdialysis assay of noradrenaline levels in the locus coeruleus (LC). Further analyses were performed to observe the effect of yohimbine on the treatment and the impact of AM404 treatment, a metabolite of acetaminophen, on noradrenaline levels in the LC. KEY FINDINGS: In all phases, intravenous acetaminophen had a significant anti-hyperalgesic effect (p < 0.05). There was a significant time-dependent increase in the noradrenaline concentration within the LC (acetaminophen versus saline treatment; at 30 min, p < 0.001; 60 min, p < 0.01) in the subacute pain model, but not in the acute and late phase pain models. Intrathecal pre-injection of yohimbine attenuated the anti-hyperalgesic effect after acetaminophen injection only in the subacute model (p < 0.05). In the subacute pain model, intracerebroventricular administration of AM404 showed the same trend in noradrenaline levels as acetaminophen administration (AM404 versus vehicle group at 30 min, p < 0.001). SIGNIFICANCE: We found the descending noradrenergic inhibitory system is involved in the antinociceptive action of acetaminophen in the subacute phase of inflammatory pain.

Hemodynamic Changes via the Lung Recruitment Maneuver Can Predict Fluid Responsiveness in Stroke Volume and Arterial Pressure During One-Lung Ventilation.

BACKGROUND: We aimed to evaluate the ability of lung recruitment maneuver-induced hemodynamic changes to predict fluid responsiveness in patients undergoing lung-protective ventilation during one-lung ventilation (OLV). METHODS: Thirty patients undergoing thoracic surgery with OLV (tidal volume: 6 mL/kg of ideal body weight and positive end-expiratory pressure: 5 cm H2O) were enrolled. The study protocol began 30 minutes after starting OLV. Simultaneous recordings were performed for hemodynamic variables of heart rate, mean arterial pressure (MAP), stroke volume (SV), pulse pressure variation (PPV), and stroke volume variation (SVV) were recorded at 4 time points: before recruitment maneuver (continuous airway pressure: 30 cm H2O for 30 seconds), at the end of recruitment maneuver, and before and after volume loading (250 mL over 10 minutes). Patients were recognized as fluid responders if the increase in SV or MAP was >10%. Receiver operating characteristic curves for percent decrease in SV and MAP by recruitment maneuver (ΔSVRM and ΔMAPRM, respectively) were generated to evaluate the ability to discriminate fluid responders from nonresponders. The gray-zone approach was applied for ΔSVRM and ΔMAPRM. RESULTS: Of 30 patients, there were 17 SV-responders (57%) and 12 blood pressure (BP)-responders (40%). Area under the curve (AUC) for ΔSVRM to discriminate SV-responders from nonresponders was 0.84 (95% confidence interval [CI], 0.67-0.95; P < .001). The best threshold for ΔSVRM to discriminate the SV-responders was -23.7% (95% CI, -41.2 to -17.8; sensitivity, 76.5% [95% CI, 50.1-93.2]; specificity, 84.6% [95% CI, 54.6-98.1]). For BP-responders, AUC for ΔMAPRM was 0.80 (95% CI, 0.61-0.92, P < .001). The best threshold for ΔMAPRM was -17.3% (95% CI, -23.9 to -5.1; sensitivity, 75.0% [95% CI, 42.8-94.5]; specificity, 77.8% [95% CI, 52.4-93.6]). With the gray-zone approach, the inconclusive range of ΔSVRM for SV-responders was -40.1% to -13.8% including 13 (43%) patients, and that of ΔMAPRM was -23.9% to -5.1%, which included 16 (53%) patients. CONCLUSIONS: ΔSVRM and ΔMAPRM could predict hemodynamic responses after volume expansion during OLV.

Error grid analysis for risk management in the difference between invasive and noninvasive blood pressure measurements.

PURPOSE: Invasive arterial blood pressure (IAP) and noninvasive blood pressure (NIBP) measurements are both common methods. Recently, a new method of error grid analysis was proposed to compare blood pressure obtained using two measurement methods. This study aimed to compare IAP and NIBP measurements using the error grid analysis and investigate potential confounding factors affecting the discrepancies between IAP and NIBP. METHODS: Adult patients who underwent general anesthesia in the supine position with both IAP and NIBP measurements were retrospectively investigated. The error grid analyses were performed to compare IAP and NIBP. In the error grid analysis, the clinical relevance of the discrepancies between IAP and NIBP was evaluated and classified into five zones from no risk (A) to dangerous risk (E). RESULTS: Overall, data of 1934 IAP/NIBP measurement pairs from 100 patients were collected. The error grid analysis revealed that the proportions of zones A-E for systolic blood pressure were 96.4%, 3.5%, 0.05%, 0%, and 0%, respectively. In contrast, the proportions for mean blood pressure were 82.5%, 16.7%, 0.8%, 0%, and 0%, respectively. The multiple regression analysis revealed that continuous phenylephrine administration (p = 0.016) and age (p = 0.044) were the significant factors of an increased clinical risk of the differences in mean blood pressure. CONCLUSIONS: The error grid analysis indicated that the differences between IAP and NIBP for mean blood pressure were not clinically acceptable and had the risk of leading to unnecessary treatments. Continuous phenylephrine administration and age were the significant factors of an increased clinical risk of the discrepancies between IAP and NIBP.

Impact of intraoperative goal-directed fluid therapy on major morbidity and mortality after transthoracic oesophagectomy: a multicentre, randomised controlled trial.

BACKGROUND: Transthoracic oesophagectomy is associated with major morbidity and mortality, which may be reduced by goal-directed therapy (GDT). The aim of this multicentre, RCT was to evaluate the impact of intraoperative GDT on major morbidity and mortality in patients undergoing transthoracic oesophagectomy. METHODS: Adult patients undergoing transthoracic oesophagectomy were randomised to receive either minimally invasive intraoperative GDT (stroke volume variation <8%, plus systolic BP maintained >90 mm Hg by pressors as necessary) or haemodynamic management left to the discretion of attending senior anaesthetists (control group; systolic BP >90 mm Hg alone). The primary outcome was the incidence of death or major complications (reoperation for bleeding, anastomotic leakage, pneumonia, reintubation, >48 h ventilation). A Cox proportional hazard model was used to examine whether the effects of GDT on morbidity and mortality were independent of other potential confounders. RESULTS: A total of 232 patients (80.6% male; age range: 36-83 yr) were randomised to either GDT (n=115) or to the control group (n=117). After surgery, major morbidity and mortality were less frequent in 22/115 (19.1%) subjects randomised to GDT, compared with 41/117 (35.0%) subjects assigned to the control group {absolute risk reduction: 15.9% (95% confidence interval [CI]: 4.7-27.2%); P=0.006}. GDT was also associated with fewer episodes of atrial fibrillation (odds ratio [OR]: 0.18 [95% CI: 0.05-0.65]), respiratory failure (OR: 0.27 [95% CI: 0.09-0.83]), use of mini-tracheotomy (OR: 0.29 [95% CI: 0.10-0.81]), and readmission to ICU (OR: 0.09 [95% CI: 0.01-0.67]). GDT was independently associated with morbidity and mortality (hazard ratio: 0.51 [95% CI: 0.30-0.87]; P=0.013). CONCLUSIONS: Intraoperative GDT may reduce major morbidity and mortality, and shorten hospital stay, after transthoracic oesophagectomy. CLINICAL TRIAL REGISTRATION: UMIN000018705.

Impact of non-invasive continuous blood pressure monitoring on maternal hypotension during cesarean delivery: a randomized-controlled study.

PURPOSE: This study aimed to investigate the efficacy of the ClearSight™ system (Edwards Lifesciences, Irvine, CA) for reducing the incidence of hypotension compared with the traditional oscillometric blood pressure monitoring in cesarean delivery under spinal anesthesia. METHODS: Forty patients undergoing cesarean delivery under spinal anesthesia were enrolled. The patients were randomly divided into two groups (Control and ClearSight groups). All patients received spinal anesthesia using 0.5% hyperbaric bupivacaine (11.5 mg) and fentanyl (10 µg). Blood pressure was managed with the same protocol using the ClearSight™ system (ClearSight group) and oscillometric blood pressure monitoring (Control group). Furthermore, we compared the accuracy of the ClearSight™ system with the traditional oscillometric monitoring for blood pressure measurement using Bland-Altman, four-quadrant plot, and polar plot analyses. RESULTS: The incidence of hypotension was significantly lower in the ClearSight group from induction to delivery (45% vs. 0%, p < 0.001) and to the end of surgery (50% vs. 20%, p = 0.049). Intraoperative nausea occurred more frequently in the Control group (45% vs. 10%, p = 0.012). The ClearSight™ system demonstrated acceptable accuracy with a bias of - 4.3 ± 11.7 mmHg throughout the procedure. Four-quadrant analysis revealed an excellent trending ability of the ClearSight™ system with a concordance rate of approximately 95%. In the polar plot analysis, the angular bias and concordance rate were - 13.5° ± 19.0° and 76.9%, respectively. CONCLUSIONS: The accuracy and trending ability of the ClearSight™ system for blood pressure measurement was clinically acceptable in cesarean delivery under spinal anesthesia, leading to reductions in maternal hypotension and nausea.

Impact of continuous non-invasive blood pressure monitoring on hemodynamic fluctuation during general anesthesia: a randomized controlled study.

This study assessed the ability of a continuous non-invasive blood pressure (BP) monitoring system to reduce intra-anesthetic hemodynamic fluctuation compared with intermittent BP cuff measurement. Forty patients undergoing total knee arthroplasty under general anesthesia were enrolled and randomly divided into two groups (Control and CS group). BP management was performed using the same protocol with BP measured by intermittent BP cuff in the Control and that by continuous non-invasive BP monitoring in the CS group. We assessed the accuracy and precision of the continuous non-invasive BP monitoring compared with BP cuff measurement using Bland-Altman, four-quadrant plot, and polar-plot analyses. Additionally, the occurrence of hypotension and hypertention during general anesthesia was compared between the two groups. The continuous non-invasive BP monitoring showed excellent accuracy of - 1.1 ± 8.1 mmHg during surgery and an acceptable trending ability with a concordance rate of 95.1% according to the four-quadrant plot analysis and an angular concordance rate of 86.7% by polar-plot analysis. Hypotension was less common in the CS group during induction of anesthesia (p = 0.002) and surgery (p = 0.008). Hypertension occurred more frequently in the Control group during emergence from anesthesia (p = 0.037). The duration of hemodynamic stability (systolic BP 80-110% of baseline) intraoperatively was longer in the CS group than in the Control group (87.7 vs. 61.9%; p < 0.001). Accuracy and trending ability of the continuous non-invasive BP monitoring was clinically acceptable, and lead to hemodynamic stability and reduction of intra-anesthetic hypotension and hypertension intraoperatively.

Pre-anesthetic stroke volume variation can predict cardiac output decrease and hypotension during induction of general anesthesia.

This study aimed to assess the reliability of stroke volume variation (SVV) in predicting cardiac output (CO) decrease and hypotension during induction of general anesthesia. Forty-five patients undergoing abdominal surgery under general anesthesia were enrolled. Before induction of anesthesia, patients were required to maintain deep breathing (6-8 times/min), and pre-anesthetic SVV was measured for 1 min by electrical cardiometry. General anesthesia was induced with propofol, remifentanil, rocuronium, and sevoflurane. Study duration was defined from the start of fluid administration till 5 min after tracheal intubation. Blood pressure (BP) was measured every minute. Cardiac output was measured continuously by electrical cardiometry. Receiver operating characteristics (ROC) curves were made regarding the incidence of decreased CO (less than 70% of the baseline) and hypotension (mean BP <65 mmHg). The risk of developing decreased CO and hypotension was evaluated by multivariate logistic regression analysis. The time from the start of the procedure to onset of decreased CO was analyzed by the Kaplan-Meier method. The area under the ROC curve and optimal threshold value of pre-anesthetic SVV for predicting decreased CO and hypotension were 0.857 and 0.693. Patients with lower SVV exhibited a significantly slower onset and lower incidence of decreased CO than those with higher SVV (p = 0.003). Multivariate logistic regression analysis indicated high pre-anesthetic SVV as being an independent risk factor for decreased CO and hypotension (odds ratio, 1.43 and 1.16, respectively). In conclusions, pre-anesthetic SVV can predict incidence of decreased CO and hypotension during induction of general anesthesia.

Hydroxyethyl starch 130/0.4 versus crystalloid co-loading during general anesthesia induction: a randomized controlled trial.

PURPOSE: Hypotension and decreased cardiac output (CO) are common adverse effects during anesthesia induction depending on the patient's pre-anesthetic cardiac condition. The aim of this study was to assess the ability of hydroxyethyl starch (HES) 130/0.4 to prevent hypotension and decreased CO during the induction of general anesthesia. METHODS: Ninety patients undergoing laparoscopic surgery were randomly divided into a HES group and a crystalloid group. Following the insertion of an intravenous line, fluid was administered to each patient at a rate of 25 ml/min using either crystalloid or HES 130/0.4. Five minutes after the initiation of fluid loading, anesthesia was induced using propofol (1.5 mg/kg), rocuronium (0.9 mg/kg), and remifentanil (0.3 mcg/kg/min). Tracheal intubation was performed 5 min after the induction of anesthesia. Following tracheal intubation, general anesthesia was maintained using remifentanil and sevoflurane. Non-invasive blood pressure (BP) level was measured at 1-min intervals and CO was measured continuously using electrical cardiometry from the start of fluid loading until 5 min after tracheal intubation. RESULTS: The number of patients with hypotension (systolic BP < 90 mmHg or 80% of baseline) was significantly lower in the HES group (p < 0.001) than in the crystalloid group. Patients in the HES group showed smaller CO decreases than did patients in the crystalloid group (p < 0.001). The Kaplan-Meier method showed a lower incidence and significantly slower onset of hypotension in the HES group (p = 0.009). Multivariate logistic regression models indicated that the use of HES is an independent factor for the prevention of both hypotension and decreased CO (below 85% of baseline; p < 0.005 for both). CONCLUSIONS: Co-loading using HES 130/0.4 prevented hypotension and decreased CO during general anesthesia induction.