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Thoracic bioimpedance and Doppler cardiac output measurement: learning curve and interobserver reproducibility.
Nine previously untrained health professionals learned to measure cardiac output (Qt) by suprasternal continuous-wave Doppler ultrasound (QtDopp) and by thoracic bioimpedance (Qtbi). Each received standardized written, videotaped, and individual instruction. First the novice, then the reference examiner, measured QtDopp or Qtbi in triplicate in an adult male subject. The reference examiner was blind to the novice measurements and the novice was not informed of the reference measurements. Each novice repeatedly measured QtDopp or Qtbi in different subjects until the mean novice QtDopp or Qtbi was within 10% of the corresponding mean reference measurement in three of four consecutive subjects. The novice observers required an average of 12.9 +/- 3.5 trials to learn to measure QtDopp, and an average of 8.4 +/- 4.5 trials to learn to measure Qtbi. The likelihood of novice agreement with the reference improved with experience. The same degree of intraobserver variability as reported for Qt measured by thermodilution (coefficient of variance less than or equal to 10%) was achieved with Qtbi in 150 (99%) of 152 triplicate measurements and QtDopp in 216 (97%) of 222 triplicate measurements. More importantly, interobserver agreement (within 10%) was achieved with both Qtbi and QtDopp. Reproducible noninvasive Qt measurement will allow these techniques to be used to monitor trend changes in Qt.
The learning curve and the cost of heart transplantation.
The effect of learning on hospital outcomes such as mortality or adverse events (the so-called "practice makes perfect" hypothesis) has been studied by numerous investigators. The effect of learning on hospital cost, however, has received much less attention. This article reports the results of a multiple regression model demonstrating a nonlinear, decreasing trend in operative and postoperative hospital costs over time in a consecutive series of 71 heart transplant patients, all treated in the same institution. The cost trend is shown to persist even after controlling for various preoperative demographic and clinical risk factors and the specific experience of individual surgeons. Using a reference case, the model predicts a cost of $81,297 for the first heart transplant procedure performed at the hospital. If this same patient had been the tenth case rather than the first, with the hospital having benefited from the experience gained in nine previous cases, the model predicts the cost would now be only $48,431, or approximately 60 percent of the cost of the first case. Had this patient been the twenty-fifth case, the predicted cost would be $35,352 (43 percent of the original cost), and had this been the fiftieth case, the cost would be $25,458 (31 percent of the original cost). The longitudinal study design used in this analysis greatly reduces the likelihood that the observed cost reduction is due to economies of scale rather than learning. The results have implications for a policy of regionalization as a tactic for containing hospital cost. Whereas others have pointed to a volume-cost relationship as an argument for the regionalization of expensive and complex hospital procedures, the present data isolate a learning-cost relationship as a separate argument for regionalization.
Modifications of the learning curve guidelines for breast cancer sentinel node biopsy.
BACKGROUND: Guidelines for the learning period of sentinel lymph node biopsy in breast cancer do not address important details such as the false negative rate way of calculation and the number of patients with positive axilla that should be included among the cases of this period. The aim of this study was to identify refinement points which should be included in the guidelines. METHODS: We studied 138 breast cancer cases of the sentinel lymph node biopsy learning period of three surgeons. The sentinel node was identified using isosulfan blue or technetium sulfur colloid or both. All patients underwent complementary axillary dissection. RESULTS: All three surgeons (A, B, C) fulfilled the guidelines' false negative rate criteria of 5, 0 and 5%, respectively, after 20 cases. However, only six, 10 and 10 cases with positive axilla, respectively, were included and the false negative rates using only these cases were 17, 0 and 10%, respectively. CONCLUSIONS: Current guidelines may lead surgeons to inappropriate conclusions about their ability to perform sentinel lymph node biopsy with an acceptable false negative rate. The learning period should include as many cases with positive axilla as possible and the false negative rate should be calculated only on those patients.
On the futility of aggregating individual learning curves.
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Learning as accumulation: a reexamination of the learning curve.
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Carotid artery stenting: effect of learning curve and intermediate-term morphological outcome.
PURPOSE: To assess the impact of learning on the rate of success and complications of carotid stenting in a single-center, one-operator series and prospectively follow a patient cohort with regard to restenosis. METHODS: In 303 patients (mean age 70 +/- 8.8 years), 320 internal carotid arteries (ICA) were treated with carotid stenting for stenoses > or = 70%. Four groups of 80 consecutive interventions were compared with regard to primary technical success and periprocedural complications. Stent patency in follow-up was assessed using duplex scanning. RESULTS: Stenting was successful in 298 (93%) arteries. The combined neurological complications (transient ischemic attacks and all strokes) and 30-day death rate was 8.2% (n = 25), but the all stroke and 30-day death rate was 3.0% (n = 9). A significant reduction in the frequency of neurological complications after the initial 80 interventions was observed (p = 0.03), but technical success was not appreciably improved with increasing experience thereafter. Over a median 12 months (interquartile range 6 to 24), cumulative patency rates were 91%, 90%, and 91% at 6, 12, and 36 months, respectively. CONCLUSIONS: Elective carotid stenting can be performed with excellent technical success, an acceptable frequency of periprocedural complications, and good intermediate-term patency. However, our findings suggest that a larger number of interventions should be performed to overcome the negative effects of the initial learning phase.
Tissue adhesive skills study: the physician learning curve.
OBJECTIVE: To compare 2 educational approaches (structured group session vs. individual instruction) of learning application techniques of 2-octylcyanoacrylate (OCA) on wounds repaired in the emergency department. METHODS: This prospective, nonrandomized, observational study was conducted in an urban hospital emergency department. Medical students, residents, and faculty were trained in the use of OCA either in a standardized group session or individually, based on their availability to attend the group session. Physicians completed a data collection form that included wound characteristics, type of instruction, and number of lacerations previously repaired with OCA. Impressions of time required, difficulty, and postrepair cosmesis were each recorded on a 5-point Likert scale. The 3 scales were totaled to yield a 15-point summary outcome measure. Univariate nonparametric comparisons of measures were performed between physicians with and without group instruction and between those with and without prior OCA experience. Using 35 subjects in each group, this study had a power of 0.95 to detect a difference of 1.5 points in the 15-point summary score, using alpha = 0.05. RESULTS: Eighty-one subjects were enrolled; the median summary score was 13 (IQR 12 to 15). There was no statistically significant difference in the summary score, nor any of its 3 components (time saved, difficulty, cosmesis), when comparing physicians with and without group instruction, nor when comparing first-time users to those with prior experience. CONCLUSION: OCA application is an easily acquired skill. Physicians were satisfied with their proficiency in OCA application, regardless of type of instruction received or number of previous lacerations repaired with OCA.
Technical proficiency of trainees performing colonoscopy: a learning curve.
BACKGROUND AND PURPOSE: We sought to provide an objective measure of the technical progress of trainees learning colonoscopy. GI fellows in our training program perform colonoscopy under supervision throughout their 2 years of fellowship. METHOD: The frequency of fellows reaching the cecum in less than 30 minutes was determined by one endoscopy instructor during the last 7 months of their first year of training and during the last 7 months of their second year. RESULTS: The mean success rate of reaching the cecum for seven first-year fellows was 54% (individual range, 25% to 86%). This compared with 86% for six second-year fellows (individual range, 73% to 93%) and with 97% for the endoscopy instructor when he did procedures without a fellow. First-year fellows during the 7-month "testing" periods believed they had reached the cecum in 5.7% of cases in which they had not. This was not a problem with second-year fellows. Counting colonoscopies done with all instructors in our program, fellows in this series each did an average of 149 colonoscopies during their first-year of training and 328 by the end of their second. CONCLUSIONS: Increasing proficiency in reaching the cecum occurs with experience over time, and continues even after completion of formal training. Individual trainees also seem to learn colonoscopy at different rates. Depending on how one defines competency, it is possible that the minimum threshold number for technical competency in colonoscopy of 100 procedures, as suggested by the ASGE, may be low.
Physicians in governance: their unique learning curve.
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Cash in on the learning curve.
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Phacoemulsification learning curve: experience of two junior trainee ophthalmologists.
PURPOSE: To establish the incidence of complications during surgery performed by junior trainees learning phacoemulsification. SETTING: Eye infirmary in a United Kingdom district general hospital. METHODS: A retrospective review of case notes of the first 102 cases of phacoemulsification procedures performed by two senior house officers was done. Main outcome measures were change in surgical plan, position of implanted lens, posterior capsule tear, vitreous loss, zonule loss, and visual outcome at discharge. Follow-up was 6 weeks. RESULTS: A posterior capsule tear occurred in 6 eyes (5.8%) and vitreous loss in 3 (2.9%). All eyes had a posterior chamber lens, 6 (5.8%) implanted in the sulcus and 96 (94.2%), in the capsular bag. Eleven eyes (10.8%) had a visual acuity of 6/18 or worse at discharge: of these, 10 had pre-existing pathology in keeping with the level of acuity. In the other eye, there was no apparent cause for the 6/18 acuity. CONCLUSIONS: The study indicates that junior trainees can be taught phacoemulsification with acceptable complication rates and visual results. The results compare favorably with reports of senior surgeons converting to phacoemulsification, trainee surgeons learning extracapsular surgery, and recently reported phacoemulsification series.
Lessons on learning about learning curves.
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New surgical procedures: can we minimise the learning curve?
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The challenge of change: allowing for the learning curve.
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Sub-tenon block: a learning curve of 100 cases. Whose benefit?
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Learning curve for oesophageal cancer surgery.
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