Developing a Checklist: Consensus Via a Modified Delphi Technique.

OBJECTIVE: To create a universal checklist of key preparatory steps to aid anesthesiologists in patient separation from cardiopulmonary bypass. DESIGN: Multistep, iterative survey with statistically guided refinement of survey items using a modified Delphi technique. SETTING: Internet-based surveys. PARTICIPANTS: Ninety active members of the Society of Cardiovascular Anesthesiologists volunteered to participate, including geographically distributed private practice and academic physicians. INTERVENTIONS: A series of checklist items was created and distributed to 90 anesthesiologists, who assessed each item's importance in preparing for patient separation from cardiopulmonary bypass and added, deleted, or modified any items as they saw fit. Items meeting a threshold of greater than 90% group acceptance were carried forward to a second survey. These items then were evaluated using a 5-point Likert scale to grade relative importance and then compared with the group's responses, creating a third survey with refined checklist items. The results then were used to generate a final survey based on each item achieving certain predefined statistical criteria, which then were scored again by the participants, generating a final checklist via statistically guided consensus. MEASUREMENTS AND MAIN RESULTS: An initial checklist containing 28 possible items was proposed to the participants. After the iterative process was completed, a final checklist of 10 items deemed essential to prepare for bypass separation was created. CONCLUSIONS: A checklist to aid in bypass separation was created with key steps derived from a statistically driven Delphi process. This technique of iterative consensus building may be useful in developing additional safety checklists.

Effect of increasing heart rate and tidal volume on stroke volume variability in vascular surgery patients.

OBJECTIVE: Because heart rate affects ventricular filling, the aim of the present study was to assess the effects of increasing heart rate and tidal volume on stroke volume variability to determine whether this dynamic index is heart-rate dependent. DESIGN: Prospective, randomized study. SETTING: Single university hospital. PARTICIPANTS: Eighteen vascular surgery patients having general anesthesia and endotracheal intubation with an arterial catheter connected to the Vigileo FloTrac system (Edwards Lifesciences, Irvine, CA) and a transesophageal atrial pacemaker (CardioComman Inc, Tampa, FL). INTERVENTION: A 2 × 2 factorial study of changes in heart rate (80 bpm and 110 bpm) and tidal volume (6 mL/kg and 10 mL/kg). MEASUREMENTS AND MAIN RESULTS: With tidal volume at 6 mL/kg, increasing heart rate from 80 mL/kg to 110 bpm caused stroke volume variability to increase from 12.2% ± 5.7% to 13.2% ± 5.3% (p<0.05), and with tidal volume at 10 mL/kg, increasing heart rate from 80 mL/kg to 110 bpm caused stroke volume variability to increase from 19.7% ± 7.9% to 22.0% ± 8.6% (p<0.05). In comparison, increasing tidal volume from 6 mL/kg to 10 mL/kg produced a significantly greater effect on stroke volume variability than increasing heart rate. CONCLUSIONS: Stroke volume variability is sensitive to increases in heart rate in addition to tidal volume. Increasing heart rate caused stroke volume variability to increase significantly, although not to the same magnitude as increasing tidal volume. When using dynamic volume indices, clinicians should be aware of increases in heart rate, although its clinical impact may be relatively minor compared with changes in tidal volume.

Checklist usage decreases critical task omissions when training residents to separate from simulated cardiopulmonary bypass.

OBJECTIVE: Separation from cardiopulmonary bypass (CPB) requires multiple preparatory steps, during which mistakes, omissions, and human errors may occur. Checklists have been used extensively in aviation to improve performance of complex, multistep tasks. The aim of this study was to (1) develop a checklist using a modified Delphi process to identify essential steps necessary to prepare for separation from CPB, and (2) compare the frequency of completed items with and without the use of a checklist in simulation. It was hypothesized that the use of a checklist would reduce the number of omissions. DESIGN: High-fidelity simulation study. SETTING: University-affiliated tertiary care facility. PARTICIPANTS: Seven cardiac anesthesiologists created a checklist using a modified Delphi process. Ten residents participated in 4 scenarios separating from CPB in simulation. INTERVENTIONS: Each scenario was performed first without a checklist and then again with a checklist. An observer graded participants' performance. MEASUREMENTS AND MAIN RESULTS: A pre-separation checklist containing 9 tasks was created using the Delphi process. Without using this checklist, 4 tasks were completed in at least 75% of scenarios, and 8 tasks were completed at least 75% of the time when using the checklist. There was a significant improvement in completion of 5 of the 9 items (p< 0.01). CONCLUSIONS: A modified Delphi process can be used to create a checklist of steps in preparing to separate from CPB. Using this checklist during simulation resulted in increased frequency of completing designated tasks in comparison to relying on memory alone. Checklists may reduce omission errors during complex periods of anesthesiologists' perioperative workflow.

Accuracy of noninvasive estimated continuous cardiac output (esCCO) compared to thermodilution cardiac output: a pilot study in cardiac patients.

OBJECTIVE: To compare the noninvasive estimated continuous cardiac output (esCCO), device-derived cardiac output (CO) to simultaneous pulmonary artery catheter (PAC) thermodilution (TD) CO. DESIGN: A prospective study comparing pulse wave transit time (estimated continuous cardiac output, esCCO; Nihon Kohden, Tokyo, Japan) to intermittent TD CO. SETTING: One academic hospital. PARTICIPANTS: Patients presenting for cardiac surgery. INTERVENTIONS: Intraoperative CO measurements at 4 distinct time points (after induction, after sternotomy, after cardiopulmonary bypass, and after chest closure). MEASUREMENTS AND MAIN RESULTS: The study population consisted of American Society of Anesthesiologists (ASA) IV subjects, 27 (77%) males and 8 (23%) females, with a mean age of 64.6 ± 12.2 years. Data points from esCCO and TD were collected simultaneously and means per time point compared using Bland-Altman, Pearson R coefficient, and percent error. Mean TD CO for the study was 5.4 L/min. The Pearson R coefficient, percent error, and bias in L/min were: 0.57, 44%, 0.66 (after induction); 0.54, 51%, 0.88 (after sternotomy); 0.60, 60%, 0.95 (after cardiopulmonary bypass); and 0.57, 60%, 0.75 (after chest closure) respectively. CONCLUSIONS: esCCO is easy to use and provides continuous CO measurements, but has wide limits of agreement and large percentage errors with a consistently positive bias in comparison to TD.

The pocket echocardiograph: a pilot study of its validation and feasibility in intubated patients.

BACKGROUND: The clinical use of miniaturized echocardiograph devices is expanding due to the potential to rapidly assess cardiac function in the critically ill patient. Novice echocardiographers have used the pocket echocardiograph (PE) to estimate ejection fraction in ambulatory patients, but have not evaluated intubated patients. We hypothesize that a novice echocardiographer can use PE to acquire interpretable cardiac images, and provide an accurate tool for estimating ejection fraction. METHODS: Subjects scheduled for cardiac surgery underwent blinded transesophageal echocardiography (TEE) and PE during a hemodynamically stable period after endotracheal intubation prior to incision. A single cardiology fellow acquired all PE images. The fellow and an experienced echocardiographer interpreted PE studies offline in a blinded fashion, visually estimating ejection fraction and assigning an image quality grade. Comparisons were made to the TEE study. RESULTS: Subjects (n = 22) were 81% male; age 69 ± 9 years, and had a mean ejection fraction of 51% ± 10.0%. Parasternal images were adequate in the vast majority of patients (77%), limited in 14%, and unacceptable in 9%, while apical (41%, 45%, and 14%) and subcostal (36%, 32%, and 32%) image quality was inferior. Ejection fraction showed fair correlation, bias, and limits of agreement for the fellow's interpretation (r = 0.50, 4.9%, ± 20.7%), with stronger association for the experienced echocardiographer (r = 0.76, 3.3%, ± 16.6%). CONCLUSION: A novice echocardiographer using PE can acquire interpretable images in the majority of intubated patients. Novice and expert echocardiographers can reasonably estimate ejection fraction using PE. PE may allow novice echocardiographers to rapidly assess cardiac function in intubated patients.

Comparison of the endotracheal cardiac output monitor to thermodilution in cardiac surgery patients.

OBJECTIVES: To compare cardiac output (CO) measurements from a novel endotracheal bioimpedance cardiac output monitor device (ECOM; ConMed, Irvine, CA) to simultaneous pulmonary artery thermodilution (TD) CO. DESIGN: Prospective study. SETTING: One academic hospital. PARTICIPANTS: Forty volunteer patients undergoing cardiac surgery. INTERVENTIONS: Intraoperative CO measurements. MEASUREMENTS AND MAIN RESULTS: Simultaneous comparative data points were collected from ECOM and TD at 4 periods: post-induction, post-sternotomy, post-cardiopulmonary bypass, and post-chest closure. The mean CO(TD) was compared with CO(ECOM) for each operative period then assessed for agreement by linear regression, Bland-Altman analysis, and percent error methods. There were 35 men (87.5%) with a mean age of 66 ± 10.7 years in the present study population. R values (p value) for the 4 time periods were 0.50 (0.002), 0.33 (0.035), 0.42 (0.007), and 0.48 (0.002). Bias and 95% limits of agreement in L/min were -0.11 (-2.40 to 2.18), 0.04 (-2.57 to 2.65), -0.06 (-2.86 to 2.74), and 0.02 (-2.42 to 2.45). Percent errors of the 4 time periods were 51%, 53%, 50%, and 48%. CONCLUSIONS: ECOM did not adequately agree with TD in patients undergoing cardiac surgery.

Validation and feasibility of intraoperative three-dimensional transesophageal echocardiographic cardiac output.

BACKGROUND: In this pilot study, we attempted to validate three-dimensional transesophageal echocardiography (3DTEE) cardiac output and assess its feasibility intraoperatively. METHODS: Twenty patients undergoing cardiac surgery underwent simultaneous cardiac output determinations during the clinically stable prebypass period by 3DTEE and thermodilution. RESULTS: The correlation coefficient between cardiac output measured by the two methods was 0.86. The 3DTEE mean bias was 0.27 L/min, limits of agreement -1.64 to 2.17 L/min (approximately +/-35%). Three-dimensional data acquisition averaged 43 s; postprocessing took 7 min. CONCLUSIONS: Three-dimensional TEE can measure cardiac output and is feasible perioperatively. Measurements have good correlation with thermodilution, though with a significant bias and wide limits of agreement.