Modeling and Management of Variation in the Operating Theatre

After having worked in the profit industry, I continued my career in 2004 as a manager of operating rooms (ORs) in a large general teaching hospital in Rotterdam. My experiences in industry management taught me to work efficiently, effectively and to excel in service to every customer and prospect. With this experience in mind I started my new job on the first of January 2004. A job in an environment filled with costly equipment and a range of highly skilled professionals such as surgeons, residents, anesthesiologists and OR staff: a multi-million euro business within a hospital. Last but not least, a business with customers: patients who needed care. Prior to starting the job, I had assumed that processes were already efficient and effective, as a result of the relatively high labor and investment costs. Being a pilot, I fully realize what a valuable resource airspace is, particularly when subject to high traffic demand. Since airspace is a fixed volume, as is the case with OR capacity, managing it is a vital activity for satisfying the needs of the aircraft operators in the most efficient and equitable manner using a sophisticated decision support system. As none of this appeared to be the case in the OR environment, I conjectured that it must be possible to run the OR more efficiently, effectively and in a more patient-centered way

Modeling and prediction of surgical procedure times

Accurate prediction of medical operation times is of crucial importance for cost efficient operation room planning in hospitals. This paper investigates the possible dependence of procedure times on surgeon factors like age, experience, gender, and team composition. The effect of these factors is estimated for over 30 different types of medical operations in two hospitals, by means of ANOVA models for logarithmic case durations. The estimation data set contains about 30,000 observations from 2005 till 2008. The relevance of surgeon factors depends on the type of operation. The factors found most often to be significant are team composition, experience, and daytime. Contrary to widespread opinions among surgeons, gender has nearly never a significant effect. By incorporating surgeon factors, the accuracy of out-of-sample prediction of case durations of about 1,250 surgical operations in 2009 is improved by up to more than 15 percent as compared to current planning procedures

Improving the efficiency of the cardiac catheterization laboratories through understanding the stochastic behavior of the scheduled procedures

  Background: In this study, we sought to analyze the stochastic behavior of Catherization Labora­tories (Cath Labs) procedures in our institution. Statistical models may help to improve estimated case durations to support management in the cost-effective use of expensive surgical resources. Methods: We retrospectively analyzed all the procedures performed in the Cath Labs in 2012. The duration of procedures is strictly positive (larger than zero) and has mostly a large mini­mum duration. Because of the strictly positive character of the Cath Lab procedures, a fit of a lognormal model may be desirable. Having a minimum duration requires an estimate of the threshold (shift) parameter of the lognormal model. Therefore, the 3-parameter lognormal model is interesting. To avoid heterogeneous groups of observations, we tested every group-car­diologist-procedure combination for the normal, 2- and 3-parameter lognormal distribution. Results: The total number of elective and emergency procedures performed was 6,393 (8,186 h). The final analysis included 6,135 procedures (7,779 h). Electrophysiology (intervention) pro­cedures fit the 3-parameter lognormal model 86.1% (80.1%). Using Friedman test statistics, we conclude that the 3-parameter lognormal model is superior to the 2-parameter lognormal model. Furthermore, the 2-parameter lognormal is superior to the normal model. Conclusions: Cath Lab procedures are well-modelled by lognormal models. This information helps to improve and to refine Cath Lab schedules and hence their efficient use.

Completion thyroidectomy of well-differentiated thyroid cancer — a prospective, miserandomised study

Wstęp: Rozpoznanie po operacjach pierwotnie niedoszczętnych raka brodawkowatego lub pęcherzykowego tarczycy wymaga radykalizacjileczenia operacyjnego i usunięcia całego gruczołu tarczowego. W zmienionych przez tkankę bliznowatą warunkach anatomicznychradykalność tych zabiegów może być niezadowalająca i w konsekwencji wpływać na wyniki tarapii.Celem pracy była ocena korzyści wynikających z zastosowania ręcznego gamma nawigatora w zabiegach wtórnie całkowitych w przypadkachdobrze zróżnicowanych raków tarczycy.Materiał i metody: W pracy przedstawiono 75 przypadków chorych z dobrze zróżnicowanymi rakami tarczycy, zakwalifikowanych doradykalizacji leczenia operacyjnego. W 43 przypadkach (grupa I) śródoperacyjnie zastosowano ręczny gamma nawigator (NavigatorGPS), 32 chorych reoperowano bez użycia wyżej wymienionego urządzenia (grupa II). W celu oceny radykalności wtórnie całkowitegozabiegu w obu grupach chorych badano pooperacyjnie stężenie tyreoglobuliny (Tg) oraz oceniano wyniki badania scyntygrafii całegociała (I131) — jodochwytność. W obu grupach porównano również wystąpienie powikłań po zabiegach wtórnie radykalnych.Wyniki: Podczas radykalizacji we wszystkich przypadkach wykonano całkowite wycięcie gruczołu tarczowego wraz z wycięciem węzłówchłonnych przedziału centralnego. Pooperacyjne średnie stęzenie Tg oraz jodochwytność były niższe w grupie I w porównaniu z grupąII: (3,32 ± 2,09 v. 4,58 ± 2,5 ng/ml, [p = 0,021] jodochwytność: 6,9 ± 3,38 (grupa I) v. 7,31 ± 2,29 ng/ml (grupa II) [p = 0,187]). Użycienawigatora nie miało wpływu na częstość wystąpienia pooperacyjnych powikłań w obu grupach chorych (p = 0,109).Wnioski: Śródoperacyjne zastosowanie nawigatora może być pomocne w osiągnięciu lepszej radykalności pierwotnie nieradykalnychoperacji, chociaż obserwowane wyniki pozwalają na stwierdzenie, że zabieg ten wykonywany przez doświadczonego operatorapozwala na osiągnięcie porównywalnej radykalności niezależnie o d śródoperacyjnej detekcji izotopowej.(Endokrynol Pol 2013; 64 (5): 335–339)Introduction: Postoperatively diagnosed papillary or follicular thyroid cancer in subtotally thyroidectomised patients requires a completionthyroidectomy. Re-operation with a gamma probe can be particularly useful in these patients.The aim of this study was to evaluate the benefits of using an intraoperative hand-held gamma detector during completion thyroidectomyin patients with well-differentiated thyroid cancer (WTC).Material and methods: 75 patients with WTC qualified for total re-thyroidectomy. In 43 patients, Group I (Nav), a hand-held gammaprobe (Navigator GPS) was used intraoperatively. 32 patients were re-operated without the gamma probe (Group II). In Group I, thyroidremnants were removed based on counted gamma signals. To estimate the radicality of reoperation in both groups, thyroglobulin (Tg)levels were determined and total body scanning (TBS) — I131 uptake — was performed.Results: Total thyroidectomy with central lymphadenectomy was performed in 75 cases. The average level of Tg and iodine uptake afterradicalisation was lower in Group I (Nav) than in Group II (3.32 ± 2.09 v. 4.58 ± 2.5 ng/mL, respectively, for Tg [p = 0.021] and 6.29 ±3.38 v. 7.31 ± 2.29 ng/mL, respectively, for iodine uptake [p = 0.187]). Additionally, the frequency of postoperative complications wascomparable, the difference in both groups was not significant, despite the use of the gamma probe (p = 0.109).Conclusions: The intraoperative use of a hand-held gamma detector can help to improve the radicality of a completion thyroidectomyprocedure after an incomplete primary thyroid resection, but the results of this procedure in the hands of an experienced surgeon arecomparable whether or not the gamma detector is used. (Endokrynol Pol 2013; 64 (5): 335–339

HMG-coenzyme A reductase inhibition, type 2 diabetes, and bodyweight: evidence from genetic analysis and randomised trials.

BACKGROUND: Statins increase the risk of new-onset type 2 diabetes mellitus. We aimed to assess whether this increase in risk is a consequence of inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the intended drug target. METHODS: We used single nucleotide polymorphisms in the HMGCR gene, rs17238484 (for the main analysis) and rs12916 (for a subsidiary analysis) as proxies for HMGCR inhibition by statins. We examined associations of these variants with plasma lipid, glucose, and insulin concentrations; bodyweight; waist circumference; and prevalent and incident type 2 diabetes. Study-specific effect estimates per copy of each LDL-lowering allele were pooled by meta-analysis. These findings were compared with a meta-analysis of new-onset type 2 diabetes and bodyweight change data from randomised trials of statin drugs. The effects of statins in each randomised trial were assessed using meta-analysis. FINDINGS: Data were available for up to 223 463 individuals from 43 genetic studies. Each additional rs17238484-G allele was associated with a mean 0·06 mmol/L (95% CI 0·05-0·07) lower LDL cholesterol and higher body weight (0·30 kg, 0·18-0·43), waist circumference (0·32 cm, 0·16-0·47), plasma insulin concentration (1·62%, 0·53-2·72), and plasma glucose concentration (0·23%, 0·02-0·44). The rs12916 SNP had similar effects on LDL cholesterol, bodyweight, and waist circumference. The rs17238484-G allele seemed to be associated with higher risk of type 2 diabetes (odds ratio [OR] per allele 1·02, 95% CI 1·00-1·05); the rs12916-T allele association was consistent (1·06, 1·03-1·09). In 129 170 individuals in randomised trials, statins lowered LDL cholesterol by 0·92 mmol/L (95% CI 0·18-1·67) at 1-year of follow-up, increased bodyweight by 0·24 kg (95% CI 0·10-0·38 in all trials; 0·33 kg, 95% CI 0·24-0·42 in placebo or standard care controlled trials and -0·15 kg, 95% CI -0·39 to 0·08 in intensive-dose vs moderate-dose trials) at a mean of 4·2 years (range 1·9-6·7) of follow-up, and increased the odds of new-onset type 2 diabetes (OR 1·12, 95% CI 1·06-1·18 in all trials; 1·11, 95% CI 1·03-1·20 in placebo or standard care controlled trials and 1·12, 95% CI 1·04-1·22 in intensive-dose vs moderate dose trials). INTERPRETATION: The increased risk of type 2 diabetes noted with statins is at least partially explained by HMGCR inhibition. FUNDING: The funding sources are cited at the end of the paper

Balancing Workload in the PACU by Using an Integrated OR Planning Methodology

Purpose: The individual scheduling of the operating rooms (ORs) has a significant influence on postoperative care at hospital facilities. We studied the effect of incorporating postoperative departments in the decision process with regard to scheduling ORs and developed an integrated OR planning methodology that determines an optimal surgery sequence and postanesthesia care unit (PACU) nursing staff level, with the objective to level the variability in inflow of patients in the PACU. Design: We developed an integrated OR planning methodology that investigates the sequencing of a surgical suite process with multiple ORs and postoperative hospital facilities. Methods: This research was performed by representing a discrete-time two-stage flow shop problem. A retrospective study was performed in which the derived model was validated using discrete-event simulation. Findings: Simulation results show that applying the integrated planning methodology decreased the variability in bed demand and smoothed the workload for the nursing staff in the PACU. Moreover, applying the algorithm led to a decrease in PACU completion time and a reduced amount of overtime hours for the surgical suite. Based on our results, we derived simple scheduling guidelines. Conclusions: Our simulation results confirmed the hypothesis that prospectively sequencing ORs' cases can effectively decrease the variability in bed demand and smoothen the workload for the staff personnel. Moreover, applying the algorithm leads to a decrease in PACU completion time and less overtime hours for the surgical suite. As such, an integrated OR planning methodology facilitates hospitals in improving OR efficiency