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.

Aerosol Generation During High Intensity Exercise-Implications for COVID-19 Transmission.

BACKGROUND AND AIM: COVID-19 can be transmitted through aerosolised respiratory particles. The degree to which exercise enhances aerosol production has not been previously assessed. We aimed to quantify the size and concentration of aerosol particles and evaluate the impact of physical distance and surgical mask wearing during high intensity exercise (HIE). METHODS: Using a prospective observational crossover study, three healthy volunteers performed high intensity cardiopulmonary exercise testing at 80% of peak capacity in repeated 5-minute bouts on a cycle ergometer. Aerosol size and concentration was measured at 35, 150 and 300 cm from the participants in an anterior and lateral direction, with and without a surgical face mask, using an Aerodynamic Particle Sizer (APS) and a Mini Wide Range Aerosol Spectrometer (MiniWRAS), with over 10,000 sample points. RESULTS: High intensity exercise generates aerosol in the 0.2-1 micrometre range. Increasing distance from the rider reduces aerosol concentrations measured by both MiniWRAS (p=0.003 for interaction) and APS (p=0.041). However, aerosol concentrations remained significantly increased above baseline measures at 300 cm from the rider. A surgical face mask reduced submicron aerosol concentrations measured anteriorly to the rider (p=0.031 for interaction) but not when measured laterally (p=0.64 for interaction). CONCLUSIONS: High intensity exercise is an aerosol generating activity. Significant concentrations of aerosol particles are measurable well beyond the commonly recommended 150 cm of physical distancing. A surgical face mask reduces aerosol concentration anteriorly but not laterally to an exercising individual. Measures for safer exercise should emphasise distance and airflow and not rely solely on mask wearing.

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.

Appropriateness of transthoracic echocardiography in preoperative elective joint arthroplasty patients.

Elective joint arthroplasty is a commonly performed procedure with postoperative cardiovascular complications occurring in up to 3% of elderly patients. Preoperative cardiac evaluation, including transthoracic echocardiography, may improve risk stratification and optimise perioperative outcomes in patients having non-cardiac surgery.This study aimed to investigate the frequency, indications, appropriateness and consequences of preoperative transthoracic echocardiography in elective joint arthroplasty patients. A one-year retrospective audit was conducted for patients who had elective joint arthroplasties performed at St Vincent's Hospital Melbourne. Patient demographics, transthoracic echocardiography indication, time between transthoracic echocardiography being ordered, performed and its impact on date of surgery were obtained via database and manual chart review. Appropriateness of transthoracic echocardiography was determined in accordance with international guidelines. This study analysed 609 elective joint arthroplasties. Of these, 116 (19%) already had a recent transthoracic echocardiography. Of the remaining 493 patients, 192 (39%) received a resting transthoracic echocardiography. Only 92 (48%) of the transthoracic echocardiography's ordered were deemed appropriate. Transthoracic echocardiography resulted in a significant delay of 31 days in time to surgery.This study indicates that almost 40% of elective joint arthroplasty patients with no recent echocardiogram are having a resting transthoracic echocardiography as part of their preoperative assessment. In 52% of cases, these are not clearly appropriate and result in delays to surgery.

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.

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.

Incidental Murmurs and the Elective Noncardiac Surgical Patient: A Case Report.

We present a case of left ventricular outflow tract (LVOT) obstruction detected by limited bedside transthoracic echocardiography (TTE). This involved a young and otherwise healthy patient presenting for elective hand surgery with a previously undetected cardiac murmur. It highlights the utility of bedside TTE as an assessment tool and shows the importance of anesthesiologists as perioperative physicians.

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.

Left Atrial Appendage Exclusion Using the AtriClip Device: A Case Series.

BACKGROUND: Atrial fibrillation (AF) affects 1.5-2% of the population and is associated with a five-fold increased lifetime risk of stroke [1]. The left atrial appendage (LAA) is the source of embolic strokes in up to 90% of patients with non-valvular AF with clots in the left atrium [2]. METHODS: We reviewed the clinical notes and echocardiographic findings of 20 patients who underwent open cardiac surgery in which concurrent AtriClip (Atricure Inc, Westchester, OH, USA) device insertion was attempted at our institution from July 2013 to February 2015. This was to examine the safety and efficacy of LAA exclusion with clip devices during open cardiac surgery. Indications for LAA exclusion included a history or suspicion of atrial arrhythmia, left ventricular dilatation, or a history of transient ischaemic attacks. RESULTS: All 20 of the 20 participants had successful placement of the clip device (100% success rate). There were no adverse events related to the device and no perioperative mortality. There were three late deaths due to chronic obstructive pulmonary disease (COPD), leukaemia, and refractory congestive cardiac failure. No late device related complications were found on follow-up imaging in the remaining patients. CONCLUSIONS: The results of our study demonstrate the LAA exclusion during open cardiac surgery with the AtriClip device is safe, has a 100% success rate, and appears to be stable over time.

Focused Cardiac Ultrasound Determines Cause of Cardiovascular Collapse During Thoracic Surgery in a Patient With Undiagnosed Pulmonary Hypertension: A Case Report.

Patients with severe pulmonary hypertension (PHT) represent a high-risk population when undergoing noncardiac surgery. During thoracic surgery with 1-lung ventilation, atelectasis of the operative lung, and frequently associated hypoxemia, is likely to exacerbate PHT and precipitate acute right ventricular failure. We present a patient with previously undiagnosed PHT who suffered 2 cardiac arrests during emergent thoracic surgery for empyema. After successful resuscitation in the operating room, she subsequently required prolonged venoarterial extracorporeal membrane oxygenation. Focused transthoracic echocardiography to evaluate cardiac function was critical in the diagnosis of PHT and subsequent treatment with sildenafil and nifedipine when discharged from the hospital.

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.

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%.

The Preoperative Patient With a Systolic Murmur.

CONTEXT: Patients with undifferentiated systolic murmurs present commonly during the perioperative period. Traditional bedside assessment and auscultation has not changed significantly in almost 200 years and relies on interpreting indirect acoustic events as a means of evaluating underlying cardiac pathology. This is notoriously inaccurate, even in expert cardiology hands, since many different valvular and cardiac diseases present with a similar auditory signal. EVIDENCE ACQUISITION: The data on systolic murmurs, physical examination, perioperative valvular disease in the setting of non-cardiac surgery is reviewed. RESULTS: Significant valvular heart disease increases perioperative risk in major non-cardiac surgery and increases long term patient morbidity and mortality. We propose a more modern approach to physical examination that incorporates the use of focused echocardiography to allow direct visualization of cardiac structure and function. This improves the diagnostic accuracy of clinical assessment, allows rational planning of surgery and anaesthesia technique, risk stratification, postoperative monitoring and appropriate referral to physicians and cardiologists. CONCLUSIONS: With a thorough preoperative assessment incorporating focused echocardiography, anaesthetists are in the unique position to enhance their role as perioperative physicians and influence short and long term outcomes of their patients.

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.

Cardiovascular collapse and hypoxemia in a man with a right-sided mediastinal mass, undiagnosed atrial septal defect, and right-to-left shunt.

A 65 year old man presented with fever, pancytopenia, hypoxemia, and cardiovascular collapse requiring intensive care unit admission. Computed tomographic pulmonary angiogram showed a right-sided mediastinal mass adjacent to the right atrium. The patient had a video-assisted thoracoscopic surgical biopsy of the mass, with selective bronchial blockade to maximize oxygenation during lung isolation. Intraoperative transesophageal echocardiography showed an unexpected large atrial secundum defect with a right-to-left shunt and intracardiac mass. This shunt could be reversed with a norepinephrine infusion, resulting in improved oxygenation. Histopathology showed potentially curative diffuse large B cell lymphoma (DLBCL).

Postanesthesia care unit discharge delay for nonclinical reasons.

Discharge of patients from the postanesthesia care unit (PACU) is often delayed for nonclinical reasons. This includes organizational issues such as patient transport, times of heavy workload for the ward and PACU nursing staff, surgical wards being unable to admit the patient, and clerical or administrative delays. We undertook a prospective study to evaluate PACU patient flow and the incidence and reasons behind delayed PACU discharge for nonclinical reasons in a tertiary referral hospital. Over a 4-month period, 2,783 patients were admitted postoperatively to our PACU. Delayed discharge because of nonclinical reasons was common, occurring in 421 (15%) patients. The median time of delayed discharge was 70 minutes (range, 25 to 420 minutes). The most common reasons for delayed discharge of the patient to the ward were no bed in the designated postoperative ward for admittance (52%), ward nurses too busy to accept the patient (32%), and ward nurses' meal breaks (10%). Delayed PACU discharge for nonclinical reasons is common and occurs predominantly because of discharge planning and organizational and staffing issues in postoperative surgical wards. Improved discharge planning, restructured staffing, and alterations in operating room scheduling may minimize these nonclinical discharge delays.

Focused transthoracic echocardiography predicts perioperative cardiovascular morbidity.

OBJECTIVES: The aim of this study was to assess the risk and predictive value of cardiac pathology detected on an anesthesiologist-performed focused transthoracic echocardiogram with adverse cardiac outcomes in the perioperative period. DESIGN: A retrospective review of 222 patients having a focused transthoracic echocardiogram and evaluating the incidence and echocardiographic risk factors associated with perioperative adverse cardiac events. SETTING: A single tertiary referral university teaching hospital. PARTICIPANTS: Two hundred twenty patients who had a focused transthoracic echocardiogram performed by an anesthesiologist. INTERVENTIONS: All patients who had a focused transthoracic echocardiogram had their discharge summary and any perioperative troponin levels reviewed, looking for evidence of adverse cardiac events, including cardiac death before discharge, myocardial infarction, pulmonary edema, hypotension requiring vasoactive drug infusion, or new arrhythmia. MEASUREMENTS AND MAIN RESULTS: Data were collected on the 222 patients who had an anesthesiologist-performed focused transthoracic echocardiogram, with 39 (18%) having an adverse cardiac event. There were 24 (11%) myocardial infarctions, 6 (2.7%) new arrhythmias, 5 (2.3%) deaths, and 4 (1.8%) episodes of severe hypotension. High-risk pathology detected on echocardiography included adverse cardiac events in 64% of the patients with pulmonary hypertension, 56% of the patients with left or right ventricular dysfunction, and 17% of the patients with stenotic valvular disease. In particular, patients with a combination of pulmonary hypertension, ventricular dysfunction, and/or stenotic valvular disease had a 77% risk of an adverse cardiac event. In contrast, no patients with a completely normal study, flow murmur, or isolated regurgitant valvular disease had adverse cardiac events. CONCLUSIONS: Anesthesiologist-performed focused transthoracic echocardiography predicts perioperative adverse cardiac events in noncardiac surgical patients.

Undergraduate student perceptions of the use of ultrasonography in the study of "living anatomy".

Ultrasonography is a noninvasive imaging modality, and modern ultrasound machines are portable, inexpensive (relative to other imaging modalities), and user friendly. The aim of this study was to explore student perceptions of the use of ultrasound to teach "living anatomy". A module utilizing transthoracic echocardiography was developed and presented to undergraduate medical, science, and dental students at a time they were learning cardiac anatomy as part of their curriculum. Relevant cardiac anatomy was explored on a student volunteer and images were projected in real-time to all students via an AV projection system. Students were asked to complete a questionnaire about the learning experience and were given the opportunity to provide open feedback. The students' evaluations of this learning experience were very positive. They agreed or strongly agreed that it was an effective way to teach anatomy (90% medical; 77% dental; 100% science) and that it was incorporated in a way that promoted reinforcement of the lecture material (83% medical; 76% dental; 100% science). They agreed or strongly agreed with statements that the experience was innovative (93% medical; 92% dental; 100% science) and stimulated interest in the subject matter (86% medical; 75% dental; 96% science), and that they would like to see more modules, exploring other anatomical sites, incorporated into the curricula (83% medical; 72% dental; 100% science). We believe that ultrasound could be a useful tool, in conjunction with traditional teaching methods, to reinforce the learning of anatomy of a variety of different undergraduate student groups.

Ultrasound-guided thoracic paravertebral blockade: a cadaveric study.

BACKGROUND: Multiple approaches to the paravertebral space have been described to produce analgesia after thoracic surgery. Ultrasound-guided regional anesthesia has the potential to improve efficacy and reduce complications via real-time visualization of the paravertebral space, surrounding structures, and the approaching needle. We compared a single- versus dual-injection technique for ultrasound-guided paravertebral blockade in a cadaver model, evaluating the spread of contrast dye and location of a catheter. METHODS: Thirty paravertebral injections and 20 catheter placements were performed on 10 fresh cadavers. The paravertebral space was identified using an ultrasound probe in the transverse plane using a linear transducer. An in-plane needle approach was used. Using analine contrast dye, a single 20-mL injection at T6-7 on one side and a dual-injection technique of 10 mL at T3-4 and T7-8 on the contralateral side were performed on each cadaver, followed by insertion of a catheter through the needle. The cadaver was then dissected to evaluate spread of contrast dye and catheter location. RESULTS: The paravertebral space was easily identified with ultrasound on each cadaver. Contrast dye was seen to surround somatic and sympathetic nerves in the paravertebral, intercostal, and epidural spaces. Contrast dye was present in 19 of 20 paravertebral spaces over 3 to 4 segments (range, 0-10) with no significant differences between single- and dual-injection techniques. Contrast dye spread more extensively across intercostal segments with 4.5 spaces (range, 2-10) covered with a single injection and 6 spaces (range, 2-8) covered with a dual-injection technique (P = 0.03). There was epidural spread of contrast in 40% of paravertebral injections in both single- and dual-injection techniques. Catheters were located in the paravertebral space (60%), prevertebral space (20%), and epidural space (5%). CONCLUSIONS: Transverse in-plane ultrasound-guided needle insertion into the thoracic paravertebral space is both feasible and reliable. However, paravertebral spread of contrast is highly variable with intercostal and epidural spread likely contributing significantly to the analgesic efficacy. A dual-injection technique at separate levels seems to cover more thoracic dermatomes because of greater segmental intercostal spread (rather than paravertebral spread) than a single-injection approach. Catheters are located in nonideal positions in 40% of cases using this in-plane technique.