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Biomedical subjects

A Macario

Publications and source records attributed to A Macario.

At least 37 records · Page 2Linked to original sources
PubMed1999

Optimal sequencing of urgent surgical cases. Scheduling cases using operating room information systems.

Optimal sequencing of urgent cases (i.e., selecting which urgent case should be performed first and which second) may enhance patient safety, increase patient satisfaction with timeliness of surgery, and minimize surgeons' complaints. Before determining the optimal sequence of urgent cases, an operating room (OR) suite must identify the primary scheduling objective to be satisfied when prioritizing pending urgent cases. These scheduling objectives may include: 1) perform the cases in the sequence that minimizes the average length of time each surgeon and patient waits; 2) perform the cases in the order that they were submitted; or 3) perform the cases based on medical priority, as prioritized by an OR director, or surgeons discussing the cases among themselves. We provide mathematical structure which can be used to program a computerized surgical services information system to assist in optimizing the sequence of urgent cases. We use an example to illustrate that the optimal sequence varies depending on the scheduling objective chosen.

Algorithms↗
PubMed1999

Decrease in case duration required to complete an additional case during regularly scheduled hours in an operating room suite: a computer simulation study.

UNLABELLED: We used Monte-Carlo computer simulation to determine whether surgical or anesthetic interventions to achieve small decreases in case duration may create enough new open operating room (OR) time to permit an additional case to be scheduled for completion in an OR suite during regular working hours. We used rules for scheduling of cases assuming that OR personnel are compensated so that the OR suite can profit financially from decreasing case duration to complete an additional case during regularly scheduled hours. The decreases in each case's duration required to create enough new open OR time to reliably (> or =95%) schedule another case were 30-39 min, 79-110 min, and 105-206 min for OR suites with 1-15 ORs and mean case durations of 1, 2, or 3 h, respectively. IMPLICATIONS: Computer simulation shows decreasing case duration is unlikely to create sufficient operating room time to reliably permit an additional case to be scheduled for completion during working hours. Additional cases may best be added to the operating room suite schedule by optimizing case scheduling, not by decreasing the duration of all cases in the suite.

Anesthesia↗
PubMed1999

Computer simulation to determine how rapid anesthetic recovery protocols to decrease the time for emergence or increase the phase I postanesthesia care unit bypass rate affect staffing of an ambulatory surgery center.

UNLABELLED: Ambulatory surgery centers (ASC) are implementing new anesthetic techniques and rapid recovery protocols in the postanesthesia care unit (PACU) to achieve earlier discharge after general anesthesia. Using computer simulation, we addressed two questions. First, what is the decrease in an ASC's operating room (OR) staff if the time from which the surgery is finished to the time the patient leaves the OR is decreased? Second, what is the decrease in PACU nursing staffing if patients bypass phase I PACU (i.e., proceed from the OR directly to the phase II PACU)? The decrease in labor costs from rapid emergence or fast-tracking depends on how staff are compensated, how many ORs routinely run concurrently, and what percentage of patients undergo general anesthesia. The results show potential decreases in ASCs' labor costs ($7.39 per case) from technologies (e.g., new anesthetics or Bispectral Index [Aspect Medical Systems, Natick, MA] monitoring) to decrease emergence times or increase the phase I bypass rates. IMPLICATIONS: Decreases in operating room and postanesthesia care unit labor costs resulting from faster emergence and phase I postanesthesia care unit bypass vary depending on the amount of routine overtime, how the staff are compensated, and how many patients are routinely anesthetized each day.

Ambulatory Surgical Procedures↗
PubMed1999

Which clinical anesthesia outcomes are both common and important to avoid? The perspective of a panel of expert anesthesiologists.

UNLABELLED: Anesthesia groups may need to determine which clinical anesthesia outcomes to track as part of quality improvement efforts. The goal of this study was to poll a panel of expert anesthesiologists to determine which clinical anesthesia outcomes associated with routine outpatient surgery were judged to occur frequently and to be important to avoid. Outcomes scoring highly in both scales could then be prioritized for measurement and improvement in ambulatory clinical practice. A mailed survey instrument instructed panel members to rate 33 clinical anesthesia outcomes in two scales: how frequently they believe the outcomes occur and which outcomes they expect patients find important to avoid. A feedback process (Delphi process) was used to gain consensus rankings of the outcomes for each scale. Importance and frequency scores were then weighted equally to qualitatively rank order the outcomes. Of the 72 anesthesiologists, 56 (78%) completed the questionnaire. The five items with the highest combined score were (in order): incisional pain, nausea, vomiting, preoperative anxiety, and discomfort from IV insertion. To increase quality of care, reducing the incidence and severity of these outcomes should be prioritized. IMPLICATIONS: Expert anesthesiologists reached a consensus on which low-morbidity clinical outcomes are common and important to the patient. The outcomes identified may be reasonable choices to be monitored as part of ambulatory anesthesia clinical quality improvement efforts.

Adult↗
PubMed1999

An operating room scheduling strategy to maximize the use of operating room block time: computer simulation of patient scheduling and survey of patients' preferences for surgical waiting time.

UNLABELLED: Determining the appropriate amount of block time to allocate to surgeons and selecting the days on which to schedule elective cases can maximize operating room (OR) use. We used computer simulation to model OR scheduling. Inputs in the computer model included different methods to determine when a patient will have surgery (on-line bin-packing algorithms), case durations, lengths of time patients wait for surgery (2 wk is the median longest length of time that the outpatients [n = 367] surveyed considered acceptable), hours of block time each day, and number of blocks each week. For block time to be allocated to maximize OR utilization, two parameters must be specified: the method used to decide on what day a patient will have surgery and the average length of time patients wait to have surgery. OR utilization depends greatly on, and increases as, the average length of time patients wait for surgery increases. IMPLICATIONS: Operating room utilization can be maximized by allocating block time for the elective cases based on expected total hours of elective cases, scheduling patients into the first available date provided open block time is available within 4 wk, and otherwise scheduling patients in "overflow" time outside of the block time.

Anesthesia↗
PubMed1999

Which clinical anesthesia outcomes are important to avoid? The perspective of patients.

UNLABELLED: Healthcare quality can be improved by eliciting patient preferences and customizing care to meet the needs of the patient. The goal of this study was to quantify patients' preferences for postoperative anesthesia outcomes. One hundred one patients in the preoperative clinic completed a written survey. Patients were asked to rank (order) 10 possible postoperative outcomes from their most undesirable to their least undesirable outcome. Each outcome was described in simple language. Patients were also asked to distribute $100 among the 10 outcomes, proportionally more money being allocated to the more undesirable outcomes. The dollar allocations were used to determine the relative value of each outcome. Rankings and relative value scores correlated closely (r2 = 0.69). Patients rated from most undesirable to least undesirable (in order): vomiting, gagging on the tracheal tube, incisional pain, nausea, recall without pain, residual weakness, shivering, sore throat, and somnolence (F-test < 0.01). IMPLICATIONS: Although there is variability in how patients rated postoperative outcomes, avoiding nausea/vomiting, incisional pain, and gagging on the endotracheal tube was a high priority for most patients. Whether clinicians can improve the quality of anesthesia by designing anesthesia regimens that most closely meet each individual patient's preferences for clinical outcomes deserves further study.

Adult↗
PubMed1999

A strategy for deciding operating room assignments for second-shift anesthetists.

UNLABELLED: We developed a relief strategy for assigning second-shift anesthetists to late-running operating rooms. The strategy relies on a statistical method which analyzes historical case durations available from surgical services information systems to estimate the expected (mean) remaining hours in cases after they have begun. We tested our relief strategy by comparing the number of hours that first-shift anesthetists would work overtime if second-shift anesthetists were assigned using our strategy versus if the anesthesia coordinator knew in advance the exact amount of time remaining in each case. Our relief strategy resulted in 3.4% to 4.9% more overtime hours for first-shift anesthetists than the theoretical minimum, as would have been obtained had perfect retrospective knowledge been available. Few additional staff hours would have been saved by supplementing our relief strategy with other methods to monitor case durations (e.g., real-time patient tracking systems or closed circuit cameras in operating rooms). IMPLICATIONS: A relief strategy that relies only on analyzing historical case durations from an operating room information system to predict the time remaining in cases performs well at minimizing anesthetist staffing costs.

Algorithms↗
PubMed1999

Statistical method to evaluate management strategies to decrease variability in operating room utilization: application of linear statistical modeling and Monte Carlo simulation to operating room management.

BACKGROUND: Operating room (OR) managers seeking to maximize labor productivity in their OR suite may attempt to reduce day-today variability in hours of OR time for which there are staff but for which there are no cases ("underutilized time"). The authors developed a method to analyze data from surgical services information systems to evaluate which management interventions can most effectively decrease variability in underutilized time. METHODS: The method uses seven summary statistics of daily workload in a surgical suite: daily allocated hours of OR time, estimated hours of elective cases, actual hours of elective cases, estimated hours of add-on cases, actual hours of add-on cases, hours of turnover time, and hours of underutilized time. Simultaneous linear statistical equations (a structural equation model) specify the relationship among these variables. Estimated coefficients are used in Monte Carlo simulations. RESULTS: The authors applied the analysis they developed to two OR suites: a tertiary care hospital's suite and an ambulatory surgery center. At both suites, the most effective strategy to decrease variability in underutilized OR time was to choose optimally the day on which to do each elective case so as to best fill the allocated hours. Eliminating all (1) errors in predicting how long elective or add-on cases would last, (2) variability in turnover or delays between cases, or (3) day-to-day variation in hours of add-on cases would have a small effect. CONCLUSIONS: This method can be used for decision support to determine how to decrease variability in underutilized OR time.

Humans↗
PubMed1999

Which algorithm for scheduling add-on elective cases maximizes operating room utilization? Use of bin packing algorithms and fuzzy constraints in operating room management.

BACKGROUND: The algorithm to schedule add-on elective cases that maximizes operating room (OR) suite utilization is unknown. The goal of this study was to use computer simulation to evaluate 10 scheduling algorithms described in the management sciences literature to determine their relative performance at scheduling as many hours of add-on elective cases as possible into open OR time. METHODS: From a surgical services information system for two separate surgical suites, the authors collected these data: (1) hours of open OR time available for add-on cases in each OR each day and (2) duration of each add-on case. These empirical data were used in computer simulations of case scheduling to compare algorithms appropriate for "variable-sized bin packing with bounded space." "Variable size" refers to differing amounts of open time in each "bin," or OR. The end point of the simulations was OR utilization (time an OR was used divided by the time the OR was available). RESULTS: Each day there were 0.24 +/- 0.11 and 0.28 +/- 0.23 simulated cases (mean +/- SD) scheduled to each OR in each of the two surgical suites. The algorithm that maximized OR utilization, Best Fit Descending with fuzzy constraints, achieved OR utilizations 4% larger than the algorithm with poorest performance. CONCLUSIONS: We identified the algorithm for scheduling add-on elective cases that maximizes OR utilization for surgical suites that usually have zero or one add-on elective case in each OR. The ease of implementation of the algorithm, either manually or in an OR information system, needs to be studied.

Algorithms↗
PubMed1999

Forecasting surgical groups' total hours of elective cases for allocation of block time: application of time series analysis to operating room management.

BACKGROUND: Allocation of the correct amount of operating room (OR) "block time" can provide surgeons with access to sufficient OR time to complete their elective cases while optimally matching staffing with the elective case workload (to maximize labor productivity). To evaluate how to predict accurately total hours of elective cases performed by a surgical group using data from surgical services information systems, the authors addressed the following questions: (1) How many previous 4-week periods of data should be used to minimize error in forecasting a surgical group's total hours of elective cases? (2) Using the number of 4-week periods from question #1, can we detect trends or correlations between successive periods that could be used to improve forecasting accuracy? (3) How can results from questions #1 and #2 be used to calculate an upper prediction bound (upper limit) for the total hours of elective cases that will be completed in a future period? Prediction bounds can be used to budget staffing accurately. METHODS: Time series analysis was performed on total hours of elective cases over 39 consecutive 4-week periods from 17 surgical groups. RESULTS: The average of 12 consecutive periods' total hours of elective cases had an appropriate error profile. The observations within each series of 12 consecutive 4-week periods followed a normal distribution, with each observation of total hours of elective cases not correlated with the subsequent observation. CONCLUSIONS: The average of the most recent 12 4-week periods can be used to predict surgical groups' future use of block time.

Algorithms↗
PubMed1999

Estimating the duration of a case when the surgeon has not recently scheduled the procedure at the surgical suite.

UNLABELLED: For some scheduled cases, there may be no previous cases of the same procedure type by the same surgeon for use in estimating the duration of the new case. We evaluated which of 16 different methods of analysis of other surgeons' cases of the same procedure type resulted in the most accurate prediction of the duration of the case that the surgeon had not recently scheduled. We analyzed durations for 4,955 cases, from an operating room information system, for which a surgeon had only scheduled the procedure once, and for which other surgeons had scheduled that same procedure one or more times. Using these data, we determined the difference between the actual duration of the new case and the estimated duration of the new case as calculated by each of the methods (average absolute error of 1.1 h with average case duration of 3.1 h). IMPLICATIONS: When no recent historical time data are available for a surgeon doing a given procedure, the mean of the durations of cases of the same scheduled procedure performed by other surgeons is as accurate an estimate as more sophisticated analyses. More research is needed to improve the precision of estimates of case durations.

Appointments and Schedules↗
PubMed1998

Setting performance standards for an anesthesia department.

The Stanford University Department of Anesthesia established performance standards by identifying aspects of their service that were related to an important "customer's" perception of quality. A "quality grid" targeted service attributes that surgeons scored high for importance and low for performance. Control charts and flow charts helped establish reasonable performance levels for "timely first case starts" and "turnaround time." Control charts indicated that a reasonable performance standard for timely first case starts was "less than 20% of first case delays will be related to anesthesia activities." For turnaround time, the standard was set at "less than 10% of all turnaround times will be greater than 15 minutes, because of anesthesia-related activities." After instituting performance standards, the performance for first case start times improved from a 36% defective rate to a 9% defective rate. Anesthesia-related delays in turnaround times stabilized at a 16% defective rate. Using appropriate service standards can improve performance.

Anesthesia Department, Hospital↗
PubMed1998

Hospital profitability for a surgeon's common procedures predicts the surgeon's overall profitability for the hospital.

STUDY OBJECTIVE: To evaluate whether a hospital's profitability for a surgeon's common procedures predicts the surgeon's overall profitability for the hospital. DESIGN: Observational study. SETTING: Community and university-affiliated tertiary hospital with 21,903 surgical procedures performed per year. PATIENTS: 7,520 patients having surgery performed by one of 46 surgeons. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Financial data were obtained for all patients cared for by all the surgeons who performed at least ten cases of one of the hospital's six most common procedures. A surgeon's overall profitability for the hospital was measured using his or her contribution margin ratio (i.e., total revenue for all of the surgeon's patients divided by total variable cost for the patients). Contribution margin was calculated twice: once with all of a surgeon's patients, and second, limiting consideration to those patients who underwent one of the six common procedures. The common procedures accounted for 22 +/- 15% of the 46 surgeons' overall caseload, 29 +/- 10% of their patients' hospital costs, and 30 +/- 12% of the hospital revenue generated by the surgeons. Hospital contribution margin ratios ranged from 1.4 to 4.2. Contribution margin ratios for common procedures and contribution margin ratios for all patients were correlated (tau = 0.58, n = 46, p < 0.0001). CONCLUSIONS: Even though most surgical cases were for uncommon procedures, a surgeon's hospital profitability on common procedures predicted the surgeon's overall financial performance. Perioperative incentive programs based on common surgical procedures (clinical pathways) are likely to accurately reflect a surgeon's financial performance on their other surgeries.

Benchmarking↗
PubMed1998

Computer simulation of changes in nursing productivity from early tracheal extubation of coronary artery bypass graft patients.

STUDY OBJECTIVE: To determine whether the results from a clinical trial, which showed that early extubation of elective coronary artery bypass graft (CABG) patients can reduce hospital costs by more rapid discharge of patients from the intensive care unit (ICU), are likely to apply to other hospitals. DESIGN: Discrete-event computer simulation. MEASUREMENTS AND MAIN RESULTS: We (1) generated simulated CABG patients, (2) had them "flow" from one condition to the next according to specified rules, and (3) calculated the labor productivity of simulated nurses who would be caring for the patients. We defined nursing labor productivity as the number of patients undergoing elective CABG cared for each year per nursing full-time equivalent working 40 hours per week. Our simulations predict that the increase in nursing labor productivity achieved by early extubation of CABG patients is sensitive to the number of elective CABG cases performed each year at the hospital and the method of compensating nurses. Hospitals with an "hourly workforce" and many cases per year are predicted to achieve a greater increase in productivity from early extubation than are hospitals with a "salaried workforce" and less active volume. At hospitals with a salaried workforce, increasing the percentage of patients extubated early may have no effect on labor productivity. CONCLUSIONS: Although "fast-tracking" protocols may offer benefits other than increasing nursing labor productivity (i.e., saving money), the results of clinical trials that demonstrate cost savings from clinical pathways that include early tracheal extubation are likely to apply only to hospitals that have similar annual CABG volume and method of compensating nurses as those in the clinical trial. To estimate the likely economic impact from early extubation protocols, a hospital should complete a simulation study with parameter values appropriate to its institution.

Computer Simulation↗
PubMed1998

The effect of a perioperative clinical pathway for knee replacement surgery on hospital costs.

UNLABELLED: Clinical pathways are being introduced by hospitals to reduce costs and control unnecessary variation in care. We studied 766 inpatients to measure the impact of a perioperative clinical pathway for patients undergoing knee replacement surgery on hospital costs. One hundred twenty patients underwent knee replacement surgery before the development of a perioperative clinical pathway, and 63 patients underwent knee replacement surgery after pathway implementation. As control groups, we contemporaneously studied 332 patients undergoing radical prostatectomy (no clinical pathway in place for these patients) and 251 patients undergoing hip replacement surgery without a clinical pathway (no clinical pathway and same surgeons as patients having knee replacement surgery). Total hospitalization costs (not charges), excluding professional fees, were computed for all patients. Mean (+/-SD) hospital costs for knee replacement surgery decreased from $21,709 +/- $5985 to $17,618 +/- $3152 after implementation of the clinical pathway. The percent decrease in hospitalization costs was 1.56-fold greater (95% confidence interval 1.02-2.28) in the knee replacement patients than in the radical prostatectomy patients and 2.02-fold greater (95% confidence interval 1.13-5.22) than in the hip replacement patients. If patient outcomes (e.g., patient satisfaction) remain constant with clinical pathways, clinical pathways may be a useful tool for incremental improvements in the cost of perioperative care. IMPLICATIONS: Doctors and nurses can proactively organize and record the elements of hospital care results in a clinical pathway, also known as "care pathways" or "critical pathways." We found that implementing a clinical pathway for patients undergoing knee replacement surgery reduced the hospitalization costs of this surgery.

Adult↗
PubMed1998

Obstetric postanesthesia care unit stays: reevaluation of discharge criteria after regional anesthesia.

BACKGROUND: Obstetric patients may have long postanesthesia care unit (OB-PACU) stays after surgery because of residual regional block or other conditions. This study evaluated whether modified discharge criteria might allow for earlier discharge without compromising patient safety. METHODS: Data were prospectively collected for 6 months for all patients (N=358) who underwent cesarean section or tubal ligation and recovered in the OB-PACU. Regional anesthesia was used in 94% of patients. The duration of anesthesia and PACU stays, the presence and treatment of events in the PACU, and the regression of neural blockade were recorded. Discharge from the OB-PACU required a 60-min minimum stay, stable vital signs, adequate analgesia, and ability to flex the knees. After completion of prospective data collection, events that kept patients in the PACU after 60 min were reevaluated as to whether patients needed to stay in the PACU for medical reasons. "Needed to stay" events included bleeding, cardiorespiratory problems, sedation, dizziness, and pain. "Safe to leave" conditions included pruritus, nausea, and residual neural blockade. The cumulative duration of OB-PACU stays not clearly justifiable for medical reasons was calculated. RESULTS: Residual block and spinal opioid side effects accounted for the majority of "unnecessary" stays. Annually, 429 h of PACU time could have been saved using the revised criteria. Complications did not develop subsequently in any patient deemed "safe to leave." CONCLUSIONS: In many obstetric patients, the duration of PACU stays could safely be shortened by continuing observation in a lower-acuity setting. This may result in greater flexibility and more efficient use of nursing personnel.

Adult↗