[Economics of operating room use at a university eye hospital]. / Wirtschaftlichkeit der Operationssaalnutzung an einer Universitäts-Augenklinik.

BACKGROUND: In ophthalmologic surgery, there are usually short operation times and thus many changes between the individual operations, which are not subject to remuneration. As in maximum care hospitals consecutive different operations with different durations are often performed, emergency operations have to be inserted and further training of colleagues is practiced, it is particularly important to generate the shortest possible transfer times in order to have both sufficient operation time and to be able to treat as many cases as possible. The aim of this work is to evaluate the efficiency of the surgical performance of a university eye hospital. MATERIAL AND METHOD: The surgeries performed in 2021 at the MHH Eye Clinic were evaluated with respect to the spectrum, number, surgery duration, transfer times and process times. In terms of personnel, each operating room was staffed with one assistant anesthesiologist, one nurse anesthetist, two operating room nurses, one surgeon, and 20% senior anesthesiologist supervision. Based on a theoretical concept, which provides an increased staffing ratio while maintaining the same infrastructure, it was calculated how many more surgeries could be performed if the transfer time was halved and whether the additional financial expense could be compensated. RESULTS: With a total of n = 2712 surgeries performed during regular duty hours (244 working days) in 2 operating rooms (average daily n = 11.1; weekly n = 53.6 and monthly n = 237.1), the average surgery duration was 37 min and the transition time 43 min. This means that the operating rooms were used for surgery for 51% of the total operating time. Main procedures were vitrectomy with n = 1350 and cataract surgery with n = 1308. The new personnel concept provided one additional operating room nurse per operating room and one additional anesthesiologist for both operating rooms. The additional costs for this personnel expenditure were calculated at approx. 300,000 € per year. The halving of the transfer time from 43 min to about 21 min through possible overlapping induction and parallel work, which was not possible until now, results in an additional operation time of about 100 min per operating room, so that at least 4 additional operations can be planned and performed. In this way, with stringent implementation and the same spatial structures with stable fixed costs, n = 976 more operations could be performed, which, minus the personnel costs, the additional material costs for surgery and anesthesia of 557,042 € and the inpatient hotel costs of 600,663 €, with an average length of stay of 2.8 days, would result in an additional revenue of about 2.4 times the additional personnel costs at the current flat rate of 3739.40 € and an average case mix index of the MHH Eye Hospital of 0.649 (total revenue: 2,155,449 €; profit margin II: 701,389 €) for the considered surgical patient collective in 2021. CONCLUSION: An increase of the personnel expenditure in the operating room for surgical subjects such as ophthalmology with shorter interventions and many changes is economically worthwhile also for a large hospital in order to enable and optimize overlapping transfers of anesthesia and surgical care. This should therefore also be considered separately, contrary to standardized staffing of the overall hospital, in order to use existing resources with their fixed costs as optimally as possible.

[Cost unit accounting of strabismus surgery at a university eye hospital]. / Kostenträgerrechnungen von strabologischen Operationen an einer Universitäts-Augenklinik.

BACKGROUND: Strabismus surgery is frequently carried out in university centers. The aim of this work was to calculate the costs of strabismus surgery at a university hospital and to assess the remuneration of costs for outpatient procedures. MATERIAL AND METHODS: Of all strabismus surgeries at the Hanover Medical School in the years 2018 and 2019, relevant surgical data, such as patient age, number of muscles operated on, incision to suture time, attendance time of the surgeons and anesthetists as well as the nursing staff, were evaluated based on the clinics own information system. During this process, the costs for personnel, material, room rental charges and overheads were computed applying cost unit accounting. RESULTS: A total of 302 operations (inpatient proportion 92.1%) were carried out in most cases with the patient under general anesthesia. The mean patient age was 31 years (median 26 years), with 33 patients being children under 6 years of age. On average 1.84 muscles were treated per intervention. The mean incision to suture time was 51.5 min, mean anesthesia time was 85 min, the attendance time of surgical as well as anesthesia nursing staff each accounted for 104 min, the additional time in the postanesthesia care unit added 66 min. Average personnel costs originating from the overall process amounted to 642.14 €, with the addition of 109.23 € for material and medication (surgery and anesthesia) and costs for cleaning and room rental (including overheads) of 178.71 €. Therefore, the overall costs of an average strabismus surgery in our collective added up to 930.08 € (minimum 491.01 €, maximum 1729.29 €). Cost accounting of subgroups yielded substantially higher costs for anesthesia in children as well as for higher numbers of muscles operated on due to different treatment duration (37 min for 1 muscle to 72 min for 3 muscles) and anesthesia time, especially in children <6 years of age (on average 22 min longer than adults and children >5 years; the differences being 11 min for 1 muscle, 25 min for 2 muscles and 30 min for 3 or more muscles). The pure costs of a strabismus surgery at this clinic seem on average to exceed the revenues for strabismus surgery in the outpatient sector calculated by the German uniform evaluation benchmark (EBM) by about a factor of 2. CONCLUSION: It could be shown that the purely economically calculated costs for strabismus surgery at a university clinic are significantly higher than the revenues achieved in the outpatient sector according to paragraph 115b, section 1, of the Social Security Act V (SGB V). Under these circumstances, such operations cannot be performed in a cost-effective manner.

[Catheterization of the subclavian vein and the risk of pneumothorax : Mechanical ventilation increases the risk of pneumothorax during infraclavicular landmark-guided subclavian vein puncture: a prospective randomized study]. / Vena-subclavia-Katheter und Pneumothoraxrisiko : Maschinelle Beatmung erhöht das Pneumothoraxrisiko während infraklavikulärer landmarkengestützter V.­subclavia-Punktion: eine prospektive randomisierte Studie.

BACKGROUND: Infraclavicular subclavian vein (SCV) catheterization is a standard procedure in anesthesia and intensive care. There is a lack of evidence on how mechanical ventilation during venipuncture of the SCV influences pneumothorax rates. OBJECTIVE: Primary hypothesis: non-inferiority of continuing vs. discontinuing mechanical ventilation during infraclavicular puncture of the SCV with respect to the pneumothorax rate. MATERIAL AND METHODS: This prospective, randomized and single-blinded study was approved by the local ethics committee. A total of 1021 eligible patients who underwent cranial neurosurgery in 2 different university hospitals were assessed between August 2014 and October 2017. Patients were randomly assigned to two groups directly before induction of anesthesia. Intervention groups for venipuncture of the SCV were mechanical ventilation: tidal volume 7 ml/kg ideal body weight, positive end expiratory pressure (PEEP) ideal body weight/10, n = 535, or apnea: manual/spontaneous, APL valve 0 mbar, n = 486. Patients and the physicians who assessed pneumothorax rates were blinded to the intervention group. Venipuncture was carried out by both inexperienced and experienced physicians. RESULTS: The pneumothorax rate was significantly higher in the mechanical ventilation group (2.2% vs. 0.4%; p = 0.012) with an odds ratio (OR) of 5.63 (95% confidence interval, CI: 1.17-27.2; p = 0.031). A lower body mass index (BMI) was associated with a higher pneumothorax rate, OR 0.89 (95% CI: 0.70-0.96; p = 0.013). CONCLUSION: In this study landmark-guided infraclavicular SCV catheterization was associated with a significantly higher rate of pneumothorax when venipuncture was performed during mechanical ventilation and not in apnea. If a short phase of apnea is justifiable in the patient, mechanical ventilation should be discontinued during the venipuncture procedure.

Post-resuscitation haemodynamics in a novel acute myocardial infarction cardiac arrest model in the pig.

BACKGROUND AND OBJECTIVES: Although a considerable amount of promising experimental research has been performed on cardiopulmonary resuscitation, clinical data indicate an ongoing limited outcome in human beings. One reason for this discrepancy could be that experimental studies use healthy animals whereas most human beings undergoing cardiopulmonary resuscitation suffer from acute or chronic myocardial dysfunction. To overcome this problem, we sought to develop a new model of myocardial infarction, that is easy to perform in all kind of laboratories and compromises on the myocardial function significantly. METHODS: Following approval by the local authorities, 14 domestic pigs were instrumented for measurement of arterial, central venous, left atrial and left ventricular pressures. Myocardial infarction was induced in eight pigs by clipping the circumflex artery close to its origin from the left coronary artery (infarction group; n = 8). Six animals (no infarction group, n = 6) served as no-infarct controls. Following a 4-min period of cardiac arrest, internal cardiac massage was performed in these two groups, and haemodynamics were recorded during the first 30 min of reperfusion. RESULTS: All animals were resuscitated successfully. Compared to the no-infarction group, the infarction group showed significantly decreased myocardial contractility, coronary perfusion pressure and cardiac index (30 min after restoration of spontaneous circulation: infarction group: 57 +/- 7 and 89 +/- 19 mL min-1 kg-1 in the no-infarction group; mean +/- SD; P < 0.05) during reperfusion. Two animals from the infarction group (25%), but none of the animals in the no-infarction group, died during the reperfusion period. CONCLUSION: These data demonstrate that clipping of the circumflex artery leads to a reduced myocardial performance after successful resuscitation, whereas the rate of restoration of spontaneous circulation is not reduced. Therefore, this set-up provides a reproducible model for future studies of post-resuscitation haemodynamics and treatment.

Modelling the pharmacodynamic interaction between remifentanil and propofol by EEG-controlled dosing.

BACKGROUND AND OBJECTIVE: Knowledge of the pharmacodynamic interaction between remifentanil and propofol is important to permit optimal dosage strategies. We studied this pharmacodynamic interaction using the median power frequency of the processed electroencephalogram as a control parameter for feedback-controlled dosing of propofol. METHODS: Twenty-one patients were given total intravenous anaesthesia with remifentanil and propofol. During three target-controlled infusion regimens, the target concentrations of remifentanil (5, 10, 15 ng mL(-1)) and propofol dosing were automatically adjusted to keep the median power frequency in the range 2 +/- 0.5 Hz. In each patient and during each remifentanil target concentration, four arterial propofol/remifentanil concentration pairs were measured. The type of interaction was tested using the relative distance from the line of additivity and the isobole was modelled using Bernstein splines. RESULTS: The results from 13 patients were used for data analysis. The measured remifentanil concentrations during the three targets were (mean +/- SD): 3.6 +/- 0.9, 8.1 +/- 2.5 and 12.4 +/- 2.8 ng mL(-1). The corresponding propofol concentrations were 2.64 +/- 0.86, 2.13 +/- 0.58 and 2.09 +/- 0.58 microg mL(-1). The data were best described with an additive type of interaction and the isobole was estimated using: ((c)Remifentanil/64.2 ng mL(-1)) + ((c)Propofol/2.61 microg mL(-1)) = 1. CONCLUSIONS: Within the studied concentration range, remifentanil and propofol showed an additive type of pharmacodynamic interaction on the electroencephalogram.

[Emergency management of an acute rupture of a perforated thoracic aortic aneurysm]. / Notfallmanagement bei akut dissezierendem und gedeckt perforiertem thorakalen Aortenaneurysma.

The emergency medical service was called to a 60-year-old woman with intensive chest pain, signs of shock, dyspnoea, intermittent paraesthesia of the right leg and disturbance of consciousness. With the diagnosis of an acute rupture of an aneurysm of the thoracic aorta, the patient was stabilised with volume, catecholamines, intubation and mechanical ventilation before being rushed to the preinformed department of cardiovascular surgery. The diagnosis was verified by transesophageal echocardiography immediately and the patient underwent surgery 2 h after onset of symptoms. Despite the rupture of the aorta and a short period of cardiac arrest, the patient recovered totally and could be discharged without any residual problems. This case shows that a ruptured thoracic aortic aneurysm can be survived although the overall mortality of this incident is more than 97%. The essentials of a good outcome are: 1. perfectly coordinated rescue operation which means an emergency medical service which includes the rupture of an aortic aneurysm in the differential diagnosis of acute chest pain, 2. an early verification of the diagnosis by means of transesophageal echocardiography which should also be carried out by anaesthesiologists due to its importance in the differential diagnosis in haemodynamic unstable patients.

Comparison of procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations at different SOFA scores during the course of sepsis and MODS.

OBJECTIVES: The relation of procalcitonin (PCT) plasma concentrations compared with C-reactive protein (CRP) was analyzed in patients with different severity of multiple organ dysfunction syndrome (MODS) and systemic inflammation. PATIENTS AND METHODS: PCT, CRP, the sepsis-related organ failure assessment (SOFA) score, the Acute Physiology, Age, Chronic Health Evaluation (APACHE) II score and survival were evaluated in 40 patients with systemic inflammation and consecutive MODS over a period of 15 days. RESULTS: Higher SOFA score levels were associated with significantly higher PCT plasma concentrations (SOFA 7-12: PCT 2.62 ng/ml, SOFA 19-24: PCT 15.22 ng/ml) (median), whereas CRP was elevated irrespective of the scores observed (SOFT 7-12: CRP 131 mg/l, SOFT 19-24: CRP 135 mg/l). PCT of non-surviving patients was initially not different from that of survivors but significantly increased after the fourth day following onset of the disease, whereas CRP was not different between both groups throughout the whole observation period. CONCLUSIONS: Measurement of PCT concentrations during multiple organ dysfunction syndrome provides more information about the severity and the course of the disease than that of CRP. Regarding the strong association of PCT and the respective score systems in future studies we recommend evaluation also of the severity of inflammation and MODS when PCT concentrations were compared between different types of disease.