The effect of restrictive compared to liberal intravenous fluid volume on hypotension in adults undergoing major abdominal surgery.

In a cardiac output (CO) sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial, it was shown that restrictive fluid management was associated with lower cardiac index at the end of surgery. However, the association of the fluid protocol with intraoperative blood pressure was less clear. This paper primarily compares rates of hypotension between the two fluid regimens. The haemodynamic effects of these protocols may increase our understanding of perioperative fluid prescription. Using a data set of arterial pressure and cardiac output measurements, this observational cohort study primarily compares intraoperative hypotension rates defined by a mean arterial pressure < 65 mmHg between liberal and restrictive fluid protocols. Secondary analyses explore predictors of invasive mean arterial pressure and doppler-derived cardiac output, including fluid volume regimens and surgical duration. 105 patients had a combined total of 835 haemodynamic data capture events from the beginning to the end of the surgery. Here we report that a restrictive regimen is not associated with a greater proportion of participants who experience at least one episode of hypotension than the liberal regimen 64.1% vs. 61.5% (mean difference 2.6%, 95% CI - 15.9% to 21%, p = 0.78). Duration of surgery was associated with an increased risk of hypotension (OR 1.05, 1 to 1.1, p = 0.038). A fluid restriction protocol compared to liberal fluid administration is not associated with lower blood pressure.

Measurement of Stroke Volume With Echocardiography Compared to Gold Standard Cardiac Magnetic Resonance Imaging: An Observational Study.

OBJECTIVES: The authors aimed to compare the assessment of left ventricular (LV) stroke volume with transthoracic echocardiography (TTE) using 2- and 3-dimensional (2D and 3D) Doppler and volumetric techniques with gold standard cardiac magnetic resonance imaging (CMR). DESIGN: An observational study. SETTING: A medical research institute. PARTICIPANTS: A total of 187 volunteer participants free of known structural heart disease. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: LV stroke volume was measured with TTE using the following 4 techniques: LV outflow tract (LVOT) pulsed wave Doppler with 2D LVOT area, LVOT pulsed wave Doppler with 3D LVOT area, 2D volumetric (Simpson's biplane), and 3D volumetric techniques. This was compared with gold standard CMR. Stroke volume measured with echocardiography underestimated stroke volume compared to CMR by all techniques (p < 0.001 for all values compared to CMR). The LVOT Doppler stroke volume with a 3D area most closely agreed with CMR, with a bias of 6.35%. This bias progressively increased with 3D volumetric (13.4%), LVOT Doppler with a 2D area (15.1%), and 2D volumetric (18.3%) stroke volume techniques, with wider limits of agreement. CONCLUSION: Of the 4 echocardiographic LV stroke volume measurement methods the authors assessed, stroke volume with LVOT Doppler using 3D measurement of LVOT area most closely approximates gold standard CMR.

Diastolic flow in the left ventricular outflow tract - A normal physiological and underappreciated echocardiographic finding.

Purpose: Diastolic waveforms in the left ventricular outflow tract (LVOT) are commonly observed with Doppler echocardiography. The incidence and mechanism are not well described. Methods: This was a retrospective observational study of 186 adult patients, athletes and non-athletes, free of known cardiac disease, presenting for comprehensive transthoracic echocardiography at a research institute. We aimed to evaluate the incidence and echocardiographic associations between LVOT diastolic waveforms. Results: Left ventricular outflow tract early to mid-diastolic waveforms were present in 100% of athletes and 95% of non-athletes. The LVOT diastolic velocity time integral was larger in athletes than non-athletes with a mean 8.3 cm (95% CI (7.6-8.9)) vs. 5.1 cm (4.4-5.9) (P < 0.0001). Multivariate predictors of this diastolic waveform were age (P = 0.002), slower heart rate (P = 0.035), higher stroke volume (P = 0.003), large mitral E (P = 0.019) and higher E/e' (P = 0.015). Discussion: An LVOT early diastolic wave is a normal physiological finding. It is related to a flow vortex redirecting diastolic mitral inflow around anterior mitral valve leaflet into the LVOT. Conclusions: Early to mid-diastolic LVOT waves are present in almost all patients but more prominent in young athletes than non-athletes. Diastolic LVOT waves increase with younger age, slower heart rate, larger stroke volume and enhanced diastolic function.

Assessment of the left ventricular outflow tract during cardiac anaesthesia with biplane transoesophageal echocardiography: An observational study.

BACKGROUND: Assessment of left ventricular outflow tract (LVOT) area is a key component of quantification of aortic stenosis and stroke volume. Current international guidelines recommend measurement of the LVOT diameter with two-dimensional (2D) echocardiography and assume a circle. This may lead to erroneous measures of aortic valve area and adversely affect peri-operative decision making. Multiplane orthogonal (biplane) and three-dimensional (3D) echocardiography imaging may allow more accurate calculation of LVOT, aortic valve area and stroke volume. OBJECTIVE: To evaluate the shape and area of the LVOT with conventional 2D diameter, short axis cross-sectional planimetry with biplane imaging and 3D multiplane reconstruction in patients undergoing cardiac surgery with transoesophageal echocardiography (TOE). DESIGN: A retrospective observational study. SETTING: A single centre university hospital. PATIENTS: 119 patients undergoing cardiac surgery with TOE. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Measurements of the shape and area of the LVOT with standard 2D TOE, short axis biplane imaging and 3D TOE. RESULTS: The LVOT shape is elliptical in 70% of patients. The (mean ±â€ŠSD, [range]) LVOT cross-sectional area with 2D TOE was 4.29 cm2 ±â€Š0.98, [2.46 to 6.70], with biplane was 4.68 cm2 ±â€Š1.03, [2.92 to 7.30] and with 3D was 4.59 cm2 ±â€Š0.99, [2.78 to 7.10]. There was a statistically significant difference (P < 0.001) in the three pairwise comparisons. 2D LVOT area had large bias (7 to 9%) and wider limits of agreement (LOA) with both biplane and 3D LVOT area (-17 to 36%). Biplane and 3D LVOT areas had small bias (1.8%) with relatively narrow LOA (-8 to 11%). CONCLUSIONS: 2D diameter measures of the LVOT assuming a circle underestimate LVOT area, underestimate aortic valve area and increase the apparent severity of aortic stenosis. This may lead to inappropriate aortic valve intervention. In a busy operating room environment, we suggest that for the calculation of stroke volume and aortic valve area, LVOT area is measured with biplane imaging. TRIAL REGISTRATION: Observational study with no interventions so trial not registered.

Effect of fluid strategy on stroke volume, cardiac output, and fluid responsiveness in adult patients undergoing major abdominal surgery: a sub-study of the Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial.

BACKGROUND: We designed a prospective sub-study of the larger Restrictive versus Liberal Fluid Therapy in Major Abdominal Surgery (RELIEF) trial to measure differences in stroke volume and other haemodynamic parameters at the end of the intraoperative fluid protocols. The haemodynamic effects of the two fluid regimens may increase our understanding of the observed perioperative outcomes. METHODS: Stroke volume and cardiac output were measured with both an oesophageal Doppler ultrasound monitor and arterial pressure waveform analysis. Stroke volume variation, pulse pressure variation, and plethysmographic variability index were also obtained. A passive leg raise manoeuvre was performed to identify fluid responsiveness. RESULTS: Analysis of 105 patients showed that the primary outcome, Doppler monitor-derived stroke volume index, was higher in the liberal group: restrictive 38.5 (28.6-48.8) vs liberal 44.0 (34.9-61.9) ml m-2; P=0.043. Similarly, there was a higher cardiac index in the liberal group: 2.96 (2.32-4.05) vs 2.42 (1.94-3.26) L min-1 m-2; P=0.015. Arterial-pressure-based stroke volume and cardiac index did not differ, nor was there a significant difference in stroke volume variation, pulse pressure variation, or plethysmographic variability index. The passive leg raise manoeuvre showed fluid responsiveness in 40% of restrictive and 30% of liberal protocol patients (not significant). CONCLUSIONS: The liberal fluid group from the RELIEF trial had significantly higher Doppler ultrasound monitor-derived stroke volume and cardiac output compared with the restrictive fluid group at the end of the intraoperative period. Measures of fluid responsiveness did not differ significantly between groups. CLINICAL TRIAL REGISTRATION: ACTRN12615000125527.

Aortic Acceleration Time and the Intraoperative Assessment of Aortic Stenosis.

OBJECTIVES: Aortic acceleration time (AAT) and the ratio of AAT to ejection time (AAT/ET) are relatively new echocardiographic measures of the severity of aortic stenosis (AS). This study investigated the utility of transesophageal echocardiography (TEE) measurements of AAT and AAT/ET to predict the severity of AS under intraoperative conditions. DESIGN: Retrospective diagnostic accuracy study. SETTING: St. Vincent's Hospital, Melbourne, Australia, from July 2007 to February 2017. PARTICIPANTS: The study comprised 199 patients who underwent aortic valve replacement (AVR) and whose aortic valves were evaluated with spectral Doppler analysis in both preoperative transthoracic echocardiography (TTE) and intraoperative TEE studies fewer than three months apart. Exclusion criteria included AVR for only aortic regurgitation, AVR of prosthetic aortic valves, and known left ventricular outflow tract obstruction. MEASUREMENTS AND MAIN RESULTS: Standard echocardiography assessment of AS and the AAT and AAT/ET measurements was performed using preoperative TTE and intraoperative TEE. The intraoperative AAT and AAT/ET were increased significantly in patients with both high- and low-gradient severe AS compared with patients without severe AS (p < 0.01). Comparing preoperative TTE and intraoperative TEE measurements showed that the AAT was significantly prolonged during general anesthesia (mean difference 9.67 msec [95% confidence interval -13.54 to -5.81]), whereas the AAT/ET was preserved (mean difference -0.0018 [95% confidence interval -0.013 to 0.0091]). An intraoperative TEE cutoff of 109 msec for AAT and 0.35 for AAT/ET had a 74% and 67% sensitivity and 72% and 78% specificity, respectively, to differentiate severe from non-severe AS. CONCLUSIONS: The AAT and AAT/ET may be useful adjuncts for the intraoperative measurement of AS. The agreement between intraoperative TEE and preoperative TTE was better with AAT/ET compared with AAT alone.

A randomised crossover comparison of two endotracheal tube introducers: the FROVA and the Flexible Tip Bougie for GlideScope intubation of a difficult airway manikin by infrequent intubators.

BACKGROUND: This unblinded randomised crossover study compares two endotracheal tube introducers (ETIs): the FROVA and the "Flexible Tip Bougie" (FTB), in an airway manikin mimicking difficult intubation with a percentage of glottic opening view of 30%. Participants were Emergency Medicine and Anaesthesia trainees with recent experience of less than twenty patient intubations. The primary outcome was time to intubation, further divided into time taken to pass the ETI and time to railroad the endotracheal tube (ETT) over the ETI. The secondary outcome was the difficulty of intubation. RESULTS: The median total time to ETT placement was significantly shorter with the FTB (37.5 s) compared with the FROVA ETI (63.0 s), P = 0.0006. The median difficulty reported (scores 0-10 with 0 being no difficulty) with the FTB was 2 compared with 5 for the FROVA, P < 0.0001. CONCLUSIONS: The FTB enabled significantly faster and easier placement of the endotracheal tube compared with the FROVA in inexperienced hands intubating a difficult intubation manikin.

Settled science or unwarranted variation in local anesthetic dosing? An analysis from an International Registry of Regional Anesthesiology.

BACKGROUND: Variation in clinical practice is often considered unwarranted when it does not reflect patient preference or evidence-based medicine. Complications from regional anesthesia such as nerve injury and systemic toxicity are dose dependent. It is currently unclear if there is significant variation with the dosing of local anesthetics (LA) in the context of the modern practice of peripheral regional anesthesia. METHODS: We analyzed data from the International Registry of Regional Anesthesia that include prospective data on peripheral regional anesthesia procedures from 21 centers located around the world. Using data from years 2011 to 2017, our primary aim was to characterize the degree of variation in dosing of LA for the top 10 most commonly performed single injection peripheral nerve blocks. Our secondary aim was to identify potential drivers of this variation. RESULTS: Among the 26 457 peripheral blocks performed, mean (±SD) LA dose per block in ropivacaine equivalents was 125.1±51.2 mg and 1.6±0.7 for mg/kg. There was large variation across all block types, with the highest variation (measured by interdecile range) in axillary blocks (143.8 mg) and lowest in interscalene blocks (83.3 mg). In a regression analysis, dose was primarily associated with the hospital (Cohen's f=0.37) where the block was administered and block type (f=0.38), less so with age (f=0.02), weight (f=0.12), gender (f=0.05) or LA (f=0.17) used. Hospital site had strong impact on variation in LA dose (f=0.88). Variation was not significantly associated with number of blocks performed by hospital site. CONCLUSIONS: Large variation in dosing for regional blocks exists within and among hospitals, which is unlikely to be warranted. For many blocks, the variation of dosing is larger than the mean dose. Hospital site had strong impact on variation in LA dose and moderate impact on mean LA dose.

The cardiovascular effects of crystalloid administration in endoscopy patients.

Intravenous fluids are commonly administered for patients having colonoscopy despite relatively little data to support this practice. It is unclear what, if any, effect crystalloid administration has on stroke volume and cardiac output in patients who are fasting and have had bowel preparation agents. We aimed to assess the physiological effect of 10 ml/kg of crystalloid administration in colonoscopy patients on haemodynamic parameters including stroke volume, stroke volume variation and cardiac output, as measured with transthoracic echocardiography. Our secondary aims were to determine whether stroke volume variation predicted fluid responsiveness in gastrointestinal endoscopy patients and whether these haemodynamic measures are different in fasting patients with bowel preparation (colonoscopy patients) compared to fasting patients alone (gastroscopy patients). We recruited 54 patients having elective gastrointestinal endoscopy (25 colonoscopy, 29 gastroscopy). All patients had stroke volume, cardiac output and stroke volume variation measured with transthoracic echocardiography at baseline. In colonoscopy patients, stroke volume, cardiac output and stroke volume variation were remeasured after 10 ml/kg of intravenous crystalloid. Administration of 10 ml/kg of crystalloid increases stroke volume by 19.6 ml ( p < 0.00005) and cardiac output by 0.81 l/min ( p < 0.001). Stroke volume variation reduced from 23% to 14% after fluid administration ( p < 0.0011). The optimum threshold of stroke volume variation to predict fluid responsiveness was 21% with a sensitivity of 77.8% and specificity of 62.5%. Administration of 10 ml/kg of crystalloid increases stroke volume and cardiac output, and reduces stroke volume variation in fasting elective colonoscopy patients.

Randomized controlled trial of probiotic use for post-colonoscopy symptoms.

BACKGROUND: Symptoms of bloating, discomfort and altered bowel function persist post-colonoscopy in up to 20% of patients. A previous randomized controlled trial of probiotics for post-colonoscopy symptoms has demonstrated a reduction in duration of pain with the use of probiotics. This was performed with air insufflation and the question was asked whether the effect would persist with the use of carbon dioxide to insufflate the colon. METHODS: Eligible patients were recruited and randomized to receive either probiotic or placebo capsules post colonoscopy. A questionnaire was completed documenting the presence of pre-procedural and post-procedural symptoms for the following 2 weeks. The results were entered into a database and processed by an independent statistician. The primary outcome was mean pain score and incidence of bloating over the first 7 days and at 14 days post procedure. The secondary outcome was the time to return of normal bowel function. RESULTS: Two hundred and forty participants were recruited and randomized (120 probiotic and 120 placebo). Data were available for 75 patients in the probiotic and 75 in the placebo group. There was no significant difference between groups in post-procedural discomfort, bloating nor time to return of normal bowel function. Subgroup analysis of the patients with preexisting symptoms showed a reduction in incidence of bloating with the use of probiotics. CONCLUSION: There may be a role for the use of probiotics in the subgroup of patients with preexisting symptoms; however, routine use of probiotics to ameliorate post-procedural symptoms of carbon dioxide insufflation colonoscopy cannot be advocated.

Oesophageal or transgastric views for estimating mean pulmonary artery pressure with transoesophageal echocardiography: A prospective observational study.

BACKGROUND: Recent data suggest that in cardiac surgical patients, the pulmonary artery acceleration time (PAT) is useful for estimating mean pulmonary artery pressure (MPAP) noninvasively with transoesophageal echocardiography (TOE). The pulmonary valve can be visualised from multiple echocardiographic windows, but it is unclear which, if any, view correlates best with MPAP. OBJECTIVE(S): To compare the PAT measured with TOE from oesophageal and transgastric views with MPAP obtained invasively with a pulmonary artery catheter. DESIGN: A prospective observational study. SETTING: St. Vincent's Hospital, Melbourne, a university tertiary referral centre in Australia. PATIENTS: Sixty-three patients having cardiac surgery were included in our study. All patients had insertion of both a TOE probe and pulmonary artery catheter; this is the routine standard of care in our centre. INTERVENTION(S): Nil. MAIN OUTCOME MEASURES: During a period of haemodynamic stability, the PAT was measured first from an oesophageal view and then immediately after from a transgastric view. The results were then compared with the invasively measured MPAP. RESULTS: Simultaneous measurements of MPAP and PAT were taken in 63 patients. In two patients, these measurements were not possible in the transgastric position due to an inability to visualise the right ventricular outflow tract and pulmonary valve. A Bland-Altman analysis of the PAT measured from the upper oesophageal and transgastric views showed a mean difference of 1 ms and limits of agreement of -18 to 16 ms. The area under the receiver operating curves for predicting pulmonary hypertension with PAT were upper oesophageal view 0.99 [95% confidence interval (CI), 0.98 to 1.00] and transgastric view 0.99 (95% CI, 0.97 to 1.00). The agreement between the results from these two views in the diagnosis of pulmonary hypertension (defined as PAT < 107 ms) was 93.4% with a kappa of 0.85 (95% CI, 0.59 to 1.00). There is an inverse curvilinear relationship between PAT and MPAP. Using a cut-off of 107 ms, the upper oesophageal view predicted pulmonary hypertension (defined as MPAP > 25 mmHg) with a sensitivity of 94.7% and specificity of 97.6%. The transgastric view predicted pulmonary hypertension with a sensitivity of 89.4% and specificity of 95.2%. CONCLUSION: Oesophageal and transgastric measurements of PAT have close agreement and a similar high ability to discriminate between people with and without pulmonary hypertension. The transgastric measurement was unobtainable in a small percentage of patients and required more probe manipulation. We would recommend PAT measurement in the upper oesophageal view.

Determining the Learning Curve for Acquiring Core Sonographic Skills for Ultrasound-Guided Axillary Brachial Plexus Block.

BACKGROUND AND OBJECTIVES: The objectives of this study were to determine the learning curve for capturing sonograms and identifying anatomical structures relevant to ultrasound-guided axillary brachial plexus block and to determine if massed was superior to distributed practice for this core sonographic skill. METHODS: Ten University of Melbourne, third- or fourth-year Doctor of Medicine students were randomized to massed or distributed practice. Participants performed 15 supervised learning sessions comprising scanning followed by feedback. A "sonographic proficiency score" was calculated by summing parameters in acquiring and interpreting the sonogram, and identifying relevant anatomical structures. RESULTS: Between the 1st and 10th sessions, the proficiency scores increased (P = 0.043). Except for one, all participants had relatively rapid increases in their "sonographic proficiency scores." There was no difference in proficiency scores between the 15th and 10th sessions (P > 0.05). There was no difference in scores between groups for the first session, (P = 0.40), 15th session (P = 0.10), or at any time. There was no difference in the slope of the increase in "sonographic proficiency score" over the first 10 scanning sessions between groups [massed, 1.1 (0.32); distributed, 0.90 (0.15); P = 0.22) presented as mean (SD)]. The 95% confidence interval for the difference in slopes between massed and distributed groups was -0.15 to 0.56. CONCLUSIONS: The proficiency of participants in capturing sonograms and identifying anatomical structures improved significantly over 8 to 10 learning sessions. Because of sample size issues, we cannot make a firm conclusion regarding massed versus distributed practice for this core sonographic skill.

A Randomized Controlled Trial of Ultrasound Versus Nerve Stimulator Guidance for Axillary Brachial Plexus Block.

BACKGROUND: Ultrasound-guided techniques improve outcomes in regional anesthesia when compared with traditional techniques; however, this assertion has not been studied with novices. The primary objective of this study was to compare sensory and motor block after axillary brachial plexus block when performed by novice trainees allocated to an ultrasound- or nerve-stimulator-guided group. A secondary objective was to compare the rates of skill acquisition between the 2 groups. METHODS: This study was a prospective, randomized, observer-blinded, 2-arm controlled trial. Anesthesia trainees participating in this trial were novices to axillary brachial plexus block and sonography. All trainee participants underwent a standardized training program. The primary outcome was combined sensory and motor block in the relevant territories 30 minutes after completion of block. A global rating scale was used to assess trainee block performance. RESULTS: The study was ceased after 12 trainees completed 153 blocks. There was no difference between groups in combined motor/sensory score (P = 0.28) or as a function of block number (P = 0.38). There was no difference in onset between groups (P = 0.38). In both groups, there was an increase in the global rating scale score (P < 0.0001) and reduced preblock survey and block performance times (P = 0.001) with experience. CONCLUSIONS: We were unable to demonstrate a difference in the efficacy of axillary brachial plexus block performed by novices when ultrasound guidance was compared with a nerve stimulator technique. There was evidence of similarly improved clinical performance of novices in both groups.

The relationship between pulmonary artery acceleration time and mean pulmonary artery pressure in patients undergoing cardiac surgery: An observational study.

BACKGROUND: A noninvasive method of estimating pulmonary arterial pressures is required, as the use of the pulmonary artery catheter (PAC) is decreasing in cardiac anaesthesia. Pulmonary hypertension is defined as a mean pulmonary artery pressure (MPAP) at least 25 mmHg and this can be estimated echocardiographically by measuring the pulmonary acceleration time (PAT). This relationship has not been validated when measured using transoesophageal echocardiography (TOE) in anaesthetised patients having cardiac surgery. OBJECTIVE: We hypothesised that there was a quantifiable relationship between PAT and MPAP. We aimed to assess this relationship in cardiac surgical patients undergoing general anaesthesia with TOE. DESIGN: An observational study. SETTING: Catholic University Hospital, Leuven, Belgium, between August and December 2013. PATIENTS: Ninety-eight patients having cardiac surgery, where intraoperative TOE was used and a PAC was inserted as part of routine care. INTERVENTIONS: Nil. MAIN OUTCOME MEASURES: PAT and MPAP were measured simultaneously with TOE and the PAC and this relationship was assessed. RESULTS: PAT and MPAP measurements were possible in all patients. There was a curvilinear relationship between PAT and MPAP with a PAT of less than 107 ms detecting pulmonary hypertension with a sensitivity of 75% and a specificity of 94.8%. The area under the receiver operating characteristic (ROC) curve was 0.87 [95% confidence interval (95% CI) 0.80 to 0.95]. Below a PAT of 107 ms, the relationship was relatively linear and could be described by the equation MPAP (mmHg) = 77 -  (0.49 x PAT). Ninety-five percent of the pressures estimated by this equation are within ±13.8 mmHg of the measured pressure. CONCLUSION: Estimation of PAT with TOE in anaesthetised cardiac surgical patients is possible. PAT is good at discriminating between patients with and without pulmonary hypertension, with a cut-off of less than 107 ms detecting pulmonary hypertension with a sensitivity of 75% and specificity of 94.8%.

Noninvasive estimation of left atrial pressure with transesophageal echocardiography.

BACKGROUND: The pulmonary artery catheter (PAC) has historically been used to measure cardiac filling pressures of which pulmonary capillary wedge pressure (PCWP) has been used as a surrogate of left atrial pressure (LAP) and left ventricular end-diastolic pressure. Increasingly, the use of the PAC has been questioned in the perioperative period with multiple large studies unable to clearly demonstrate benefit in any group of patients, resulting in a declining use in the perioperative period. Alternative methods for the noninvasive estimation of left-sided filling pressures are required. Echocardiography has been used to provide noninvasive estimation of PCWP and LAP, based on evaluating mitral inflow velocity with the E and A waves and looking at movement of the mitral annulus with tissue Doppler (e'). AIM: The aim of our study was to assess the relationship between PCWP and E/e' in cardiac surgical patients with transesophageal echocardiography (TOE). DESIGN: A prospective observational study. SETTING: Cardiac surgical patients in a single quaternary referral university teaching hospital. METHODS: The ratio of mitral inflow velocity (E wave) to mitral annular tissue velocity (e') (the E/e' ratio) and PCWP of 91 patients undergoing general anesthesia and cardiac surgery were simultaneously recorded, with the use of TOE and a PAC. RESULTS: The correlation between E/e' and PCWP was modest with a Spearman rank correlation coefficient of 0.29 (P = 0.005). The area under the receiver operating characteristic curve for using E/e' to predict elevated PCWP (≥18 mmHg) was 0.6825 (95% confidence interval: 0.57-0.80), indicating some predictive utility. The optimum threshold value of E/e' was 10 which had 71% sensitivity and 60% specificity to predict a PCWP ≥18 mmHg. CONCLUSIONS: Noninvasive measurements of E/e' in general cardiac surgical patients have only a modest correlation and does not reliably estimate PCWP.

Pleth variability index predicts fluid responsiveness in mechanically ventilated adults during general anesthesia for noncardiac surgery.

OBJECTIVE: To investigate whether the pleth variability index (PVI), derived noninvasively from a pulse oximeter probe, would predict fluid responsiveness in patients undergoing noncardiac surgeries. DESIGN: A clinical, prospective, observational study. SETTING: Operating room of a tertiary care hospital. PARTICIPANTS: Twenty-nine adult patients undergoing a range of noncardiac surgeries, requiring general anesthesia, tracheal intubation, and mechanical ventilation. INTERVENTIONS: Intravenous volume expansion with 500 mL of colloid following induction of general anesthesia and after a period of hemodynamic stability before the start of surgery. MEASUREMENTS AND MAIN RESULTS: Baseline values for PVI and stroke volume index, derived from an esophageal Doppler monitor, were compared with final values after the volume expansion. Patients were classified into fluid responders and nonresponders based on a stroke volume index increase of ≥ 10%. The optimal cut-off value for baseline pleth variability index for predicting fluid responsiveness was determined. There were 17 responders (59%) to the 500-mL volume expansion. Baseline PVI value was significantly different between responders and nonresponders (16.5 ± 6.4% v 10.3 ± 2.7%; p = 0.004). Receiver operating characteristic analysis demonstrated significant predictive ability of an increase in stroke volume index for PVI with area under the curve of 0.84 (95% confidence interval = 0.69-0.99). The optimal cut-off value for baseline PVI was 10.5%, with a sensitivity of 88% and a specificity of 67%. CONCLUSIONS: Pleth variability index is predictive of fluid responsiveness in adult patients undergoing noncardiac surgery.

Evaluation of a task-specific checklist and global rating scale for ultrasound-guided regional anesthesia.

UNLABELLED: Checklists and global rating scales (GRSs) are used for assessment of anesthesia procedural skills. The purpose of this study was to evaluate the reliability and validity of a recently proposed assessment tool comprising a checklist and GRS specific for ultrasound-guided regional anesthesia. METHODS: In this prospective, fully crossed study, we videotaped 30 single-target nerve block procedures performed by anesthesia trainees. Following pilot assessment and observer training, videos were assessed in random order by 6 blinded, expert observers. Interrater reliability was evaluated with intraclass correlation coefficients (ICCs) based on a 2-way random-effects model that took into account both agreement and correlation between observer results. Construct validity and feasibility were also evaluated. RESULTS: The ICC between assessors' total scores was 0.44 (95% confidence interval, 0.27-0.62). All 6 observers scored "experienced trainees" higher than "inexperienced trainees" (median total score 76.7 vs 54.2, P = 0.01), supporting the test's construct validity. The median time to assess the videos was 4 minutes 29 seconds. CONCLUSIONS: This is the first study to evaluate the reliability and validity of a combined checklist and GRS for ultrasound-guided regional anesthesia using multiple observers and taking into account both absolute agreement and correlation in determining the ICC of 0.44 for interrater reliability. There was evidence to support construct validity.

Are patients satisfied after peripheral nerve blockade? Results from an International Registry of Regional Anesthesia.

INTRODUCTION: Peripheral nerve blockade (PNB) is associated with superior outcomes compared with opioids; however, little is known regarding patients' perceptions of the care they have received. Patient satisfaction is emerging as an important indicator of quality of health care, and identifying deficiencies in discrete aspects of satisfaction may allow targeted interventions to improve quality. In this study, we analyze data relevant to patient satisfaction from the International Registry of Regional Anesthesia. The primary objective of this analysis was to report the results of a patient-satisfaction questionnaire and to determine predictors associated with unwillingness to have PNB repeated in the case of future surgery. METHODS: The questionnaire used in this study was derived from this registry's results and from previously validated questionnaires and addressed 3 domains of importance, namely, provision of information, pain, and interaction with the anesthesiologist. The 11-item written, multidimensional questionnaire was given to patients within 2 days postoperatively. The primary outcome was willingness to have PNB repeated in the event of future similar surgery. RESULTS: Data related to 9969 surgical procedures were collected between July 1, 2011, and March 31, 2013. The survey response rate was 61.6%. Most respondents-94.6% (95% confidence interval, 94.0%-95.1%)--stated that they were willing to have a repeat PNB. Ninety percent of respondents were satisfied or completely satisfied with the information provided about the nerve block, as well as the anesthesiologist-patient interaction. Patients who were dissatisfied with either of these domains (ie, information provision or professional interaction) were less willing to undergo repeat PNB, as were patients who reported significant pain during the nerve block procedure. CONCLUSIONS: A high proportion of survey respondents were willing to undergo repeat PNB in case of future surgery and were satisfied with their anesthetic care. Targeted interventions to improve quality of PNB should be aimed at improving comfort, information provision, and physician-patient interaction.

Ultrasound guidance reduces the risk of local anesthetic systemic toxicity following peripheral nerve blockade.

BACKGROUND AND OBJECTIVES: Local anesthetic systemic toxicity (LAST) is a potentially life-threatening complication of local anesthetic administration. In this article, the results of the Australian and New Zealand Registry of Regional Anaesthesia were analyzed to determine if ultrasound-guided peripheral nerve blockade (PNB) was associated with a reduced risk of LAST compared with techniques not utilizing ultrasound technology. METHODS: The period of study for this multicenter study involving 20 hospitals was from January 2007 through May 2012. The primary outcome was LAST comprising minor, major, and cardiac arrest (due to toxicity) events determined using standardized definitions. Multivariable logistic regression models and propensity score analyses were used to determine significant event predictors. RESULTS: The study population comprised 20,021 patients who received 25,336 PNBs. There were 22 episodes of LAST, resulting in an incidence of LAST of 0.87 per 1000 PNBs (95% confidence interval, 0.54-1.3 per 1000). Ultrasound guidance was associated with a reduced incidence of local anesthetic toxicity. Site of injection, local anesthetic type, dose per weight, dose, and patient weight were all predictors of LAST. CONCLUSIONS: This study provides the strongest evidence, to date, that ultrasound guidance may improve safety because it is associated with a reduced risk of LAST following PNB.