Virucidal efficacy of an ozone-generating system for automated room disinfection

Besides conventional prevention measures, no-touch technologies based on gaseous systems have been introduced in hospital hygiene for room disinfection. The whole-room disinfectant device Sterisafe Pro, which creates ozone as a biocidal agent, was tested for its virucidal efficacy based on Association Française de Normalisation Standard NF T 72-281:2014. All test virus titres were reduced after 150 and 300 min of decontamination, with mean reduction factors ranging from 2.63 (murine norovirus) to 3.94 (simian virus 40). These results will help to establish realistic conditions for virus inactivation, and assessment of the efficacy of ozone technology against non-enveloped and enveloped viruses.

Virucidal efficacy of different formulations for hand and surface disinfection targeting SARS CoV-2

In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming ‘virucidal activity against enveloped viruses’ as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming ‘virucidal activity against enveloped viruses’ based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

A critical comparison between the semisitting and the supine positioning in vestibular schwannoma surgery: subgroup analysis of a randomized, multicenter trial

OBJECTIVE

Patient positioning in vestibular schwannoma (VS) surgery is a matter of ongoing discussion. Factors to consider include preservation of cranial nerve functions, extent of tumor resection, and complications. The objective of this study was to determine the optimal patient positioning in VS surgery.

METHODS

A subgroup analysis of a randomized, multicenter trial that investigated the efficacy of prophylactic nimodipine in VS surgery was performed to investigate the impact of positioning (semisitting or supine) on extent of resection, functional outcomes, and complications. The data of 97 patients were collected prospectively. All procedures were performed via a retrosigmoid approach. The semisitting position was chosen in 56 patients, whereas 41 patients were treated while supine.

RESULTS

Complete resection was obtained at a higher percentage in the semisitting as compared to the supine position (93% vs 73%, p = 0.002). Logistic regression analysis revealed significantly better facial nerve function in the early postoperative course in the semisitting group (p = 0.004), particularly concerning severe facial nerve paresis (House-Brackmann grade IV or worse; p = 0.002). One year after surgery, facial nerve function recovered. However, there was still a tendency for better facial nerve function in the semisitting group (p = 0.091). There were no significant differences between groups regarding hearing preservation rates. Venous air embolism with the necessity to terminate surgery occurred in 2 patients in the semisitting position (3.6%). Supplementary analysis with a 2-tailed permutation randomization with 10,000 permutations of treatment choice and a propensity score matching showed either a tendency or significant results for better facial nerve outcomes in the early postoperative course and extent of resection in the semisitting group.

CONCLUSIONS

Although the results of the various statistical analyses are not uniform, the data indicate better results concerning both a higher rate of complete removal (according to the intraoperative impression of the surgeon) and facial nerve function after a semisitting as compared to the supine position. These advantages may justify the potential higher risk for severe complications of the semisitting position in VS surgery. The choice of positioning has to consider all individual patient parameters and risks carefully.

Time course of pain response and toxicity after whole-nerve-encompassing LINAC-based stereotactic radiosurgery for trigeminal neuralgia-a prospective observational study

PURPOSE

To prospectively evaluate the time course of pain response and toxicity after linear accelerator-based whole-nerve-encompassing radiosurgery (LINAC-SRS) using a uniform treatment schedule for dosing and target volume definition in patients with refractory trigeminal neuralgia.

METHODS

From December 2012 to December 2016, 21 patients were treated using a standardized protocol. Patients received LINAC-SRS with 70 Gy to the cisternal portion while aiming for the 90% isodose to fully envelope the nerve in one cross-sectional plane. Data on pain, analgesics, and toxicity were gathered prospectively. Four time intervals (1-6, 6-12, 12-18, and 18-24 months) were defined and compared to baseline and each other.

RESULTS

The median follow-up from radiotherapy was 16 months. Freedom from pain was achieved at least once in 90.5, 81.0, and 85.7% of patients for everyday pain, rest pain, and pain peaks, respectively. At 1-6 months, pain was significantly reduced in everyday routine (mean VAS, 2.0/10 vs. 5.8/10; P = 0.004), at rest (1.5/10 vs. 4.0/10; P = 0.002), and for pain peaks (2.9/10 vs. 10/10; P < 0.001), as was the number of analgesics (mean 1.5 vs. 2.9; P < 0.001). No significant increase in pain or analgesics was observed for subsequent time intervals. At last follow-up, reduction in pain compared to baseline for everyday routine (2.1/10 vs. 5.8/10; P = 0.010) and for pain peaks (3.3/10 vs. 10/10; P < 0.001) was significant, whereas it was not for rest pain (1.8/10 vs. 3.9/10; P = 0.073). Most toxicities were related to trigeminal nerve impairment, with 42.9% reporting new-onset hypoesthesia at last follow-up.

CONCLUSION

This study provides prospective data after whole nerve encompassing LINAC-SRS for trigeminal neuralgia. No significant pain relapse was observed.

6th vital sign app: Testing validity and reliability for measuring gait speed

BACKGROUND

Gait speed tests are useful predictors of different health outcomes in people. These tests can be administered by the convenience of one's smartphone.

RESEARCH QUESTION

Is the 6th Vital Sign app valid and reliable for measuring gait speed?

METHODS

The study used a prospective test-retest design. Fifteen college subjects were asked to walk at their normal pace for 2 min. Each subject performed two trials. Speed was recorded by the 6th Vital Sign app, Brower timing gates, and by hand-measurement of distance walked divided by the 2 min. Criterion validity was assessed by paired t-tests, Cohen's D effect sizes, and Pearson correlation tests. Inter-trial reliability within each device was assessed with Pearson correlation tests.

RESULTS

Speed measured by the app was significantly lower than speed measured by gates (p = 0.004) and by hand-measurement (p = 0.009). The difference between gates and hand-measurement was not significant (p = 0.684). The speed measured by gates and hand-measurement were very highly correlated (r = 0.974), but speed measured by app was only moderately correlated with gates (r = 0.370) and hand-measurement (r = 0.365). The inter-trial reliability was fairly high with correlations r = 0.916, 0.944, and 0.941 when speed was measured by the app, gates, and hand-measurement, respectively.

SIGNIFICANCE

The app tended to underestimate speed when compared to gate and hand-measurements. Therefore, we conclude that the 6^th Vital Sign app is not valid for use for clinical diagnosis or prognosis.

Ulkusheilung nach Varizen-OP – Ergebnisse nach fünf Jahren

Ziel: Die Langzeitergebnisse der Varizenoperation zur Behandlung eines Ulcus cruris venosum sollten überprüft werden. Methode: Bei 63 Patienten mit vor fünf Jahren durch Operation einer Varikose der V. saphena magna behandeltem venösen Ulkus wurde der Langzeitheilungserfolg überprüft. Ergebnis: Von 63 unteren Extremitäten war in 49 Fällen innerhalb von sechs Monaten nach der Operation eine dauerhafte Abheilung des Ulkus eingetreten. Bei vier weiteren Patienten erfolgte die Heilung innerhalb von eineinhalb Jahren nach der Varizenoperation. Eine Langzeitheilung des venösen Ulkus wurde bei 84% der Patienten erreicht. Hierbei handelt es sich ausschließlich um Patienten mit einem Ulkus infolge einer Stammvarikosis. Bei 6% der Patienten (4 Beine) kam es zu rezidivierenden Ulzera, die z. Zt. unter Behandlung abgeheilt sind. Bei 6 Patienten (10%) blieb das Ulkus trotz zusätzlicher konservativer Therapie dauerhaft nach fünf Jahren weiter bestehen. Diese Patienten haben zusätzlich zur Varikose schwerwiegende Begleiterkrankungen (malignes Geschehen, PTS, AVK, Diabetes, ausgeprägte Lymphödeme etc.). Schlußfolgerung: Bei Patienten mit einer Stammvarikose und venösem Ulkus führt die Varizenoperation zu einem sehr guten dauerhaften Heilungserfolg. Eine zusätzliche schwerwiegende Begleiterkrankung beeinträchtigt die Prognose der Ulkusheilung erheblich.

Prophylactic nimodipine treatment and improvement in hearing outcome after vestibular schwannoma surgery: a combined analysis of a randomized, multicenter, Phase III trial and its pilot study

OBJECTIVE In clinical routines, neuroprotective strategies in neurosurgical interventions are still missing. A pilot study (n = 30) and an analogously performed Phase III trial (n = 112) pointed to a beneficial effect of prophylactic nimodipine and hydroxyethyl starch (HES) in vestibular schwannoma (VS) surgery. Considering the small sample size, the data from both studies were pooled. METHODS The patients in both investigator-initiated studies were assigned to 2 groups. The treatment group (n = 70) received parenteral nimodipine (1-2 mg/hour) and HES (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 72) was not treated prophylactically. Facial and cochlear nerve functions were documented preoperatively, during the inpatient care, and 1 year after surgery. RESULTS Pooled raw data were analyzed retrospectively. Intent-to-treat analysis revealed a significantly lower risk for hearing loss (Class D) 12 months after surgery in the treatment group compared with the control group (OR 0.46, 95% CI 0.22-0.97; p = 0.04). After exclusion of patients with preoperative Class D hearing, this effect was more pronounced (OR 0.38, 95% CI 0.17-0.83; p = 0.016). Logistic regression analysis adjusted for tumor size showed a 4 times lower risk for hearing loss in the treatment group compared with the control group (OR 0.25, 95% CI 0.09-0.63; p = 0.003). Facial nerve function was not significantly improved with treatment. Apart from dose-dependent hypotension (p < 0.001), the study medication was well tolerated. CONCLUSIONS Prophylactic nimodipine is safe and may be recommended in VS surgery to preserve hearing. Prophylactic neuroprotective treatment in surgeries in which nerves are at risk seems to be a novel and promising concept. Clinical trial registration no.: DRKS 00000328 ( https://drks-neu.uniklinik-freiburg.de/drks_web/ ).

Stability of hearing preservation and regeneration capacity of the cochlear nerve following vestibular schwannoma surgery via a retrosigmoid approach

OBJECTIVE The purpose of this research was to examine the stability of long-term hearing preservation and the regeneration capacity of the cochlear nerve following vestibular schwannoma (VS) surgery in a prospective study. METHODS A total of 112 patients were recruited for a randomized multicenter trial between January 2010 and April 2012 to investigate the efficacy of prophylactic nimodipine treatment versus no prophylactic nimodipine treatment in VS surgery. For the present investigation, both groups were pooled to compare hearing abilities in the early postoperative course and 1 year after the surgery. Hearing was examined using pure-tone audiometry with speech discrimination, which was performed preoperatively, in the early postoperative course, and 12 months after surgery and was subsequently classified by an independent otorhinolaryngologist using the Gardner-Robertson classification system. RESULTS Hearing abilities at 2 time points were compared by evaluation in the early postoperative course and 1 year after surgery in 102 patients. The chi-square test showed a very strong association between the 2 measurements in all 102 patients (p < 0.001) and in the subgroup of 66 patients with a preserved cochlear nerve (p < 0.001). CONCLUSIONS There is no significant change in cochlear nerve function between the early postoperative course and 1 year after VS surgery. The result of hearing performance, as evaluated by early postoperative audiometry after VS surgery, seems to be a reliable prognosticator for future hearing ability. Clinical trial registration nos.: 2009-012088-32 ( clinicaltrialsregister.eu ) and DRKS 00000328 ("AkNiPro," drks-neu.uniklinik-freiburg.de/drks_web/ ).

Prophylactic nimodipine treatment for cochlear and facial nerve preservation after vestibular schwannoma surgery: a randomized multicenter Phase III trial

OBJECTIVE

A pilot study of prophylactic nimodipine and hydroxyethyl starch treatment showed a beneficial effect on facial and cochlear nerve preservation following vestibular schwannoma (VS) surgery. A prospective Phase III trial was undertaken to confirm these results.

METHODS

An open-label, 2-arm, randomized parallel group and multicenter Phase III trial with blinded expert review was performed and included 112 patients who underwent VS surgery between January 2010 and February 2013 at 7 departments of neurosurgery to investigate the efficacy and safety of the prophylaxis. The surgery was performed after the patients were randomly assigned to one of 2 groups using online randomization. The treatment group (n = 56) received parenteral nimodipine (1-2 mg/hr) and hydroxyethyl starch (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 56) was not treated prophylactically.

RESULTS

Intent-to-treat analysis showed no statistically significant effects of the treatment on either preservation of facial nerve function (35 [67.3%] of 52 [treatment group] compared with 34 [72.3%] of 47 [control group]) (p = 0.745) or hearing preservation (11 [23.4%] of 47 [treatment group] compared with 15 [31.2%] of 48 [control group]) (p = 0.530) 12 months after surgery. Since tumor sizes were significantly larger in the treatment group than in the control group, logistic regression analysis was required. The risk for deterioration of facial nerve function was adjusted nearly the same in both groups (OR 1.07 [95% CI 0.34-3.43], p = 0.91). In contrast, the risk for postoperative hearing loss was adjusted 2 times lower in the treatment group compared with the control group (OR 0.49 [95% CI 0.18-1.30], p = 0.15). Apart from dose-dependent hypotension (p < 0.001), no clinically relevant adverse reactions were observed.

CONCLUSIONS

There were no statistically significant effects of the treatment. Despite the width of the confidence intervals, the odds ratios may suggest but do not prove a clinically relevant effect of the safe study medication on the preservation of cochlear nerve function after VS surgery. Further study is needed before prophylactic nimodipine can be recommended in VS surgery.

Hearing preservation in medial vestibular schwannomas

Object

Vestibular schwannomas (VSs) with no or little extension into the internal auditory canal have been addressed as a clinical subentity carrying a poor prognosis regarding hearing preservation, which is attributed to the initially asymptomatic intracisternal growth pattern. The goal in this study was to assess hearing preservation in patients who underwent surgery for medial VSs.

Methods

A consecutive series of 31 cases in 30 patients with medial VSs (mean size 31 mm) who underwent surgery between 1997 and 2005 via a suboccipitolateral route was evaluated with respect to pre- and postoperative cochlear nerve function, extent of tumor removal, and radiological findings. Intraoperative monitoring of brainstem auditory evoked potentials was performed in all patients with hearing. Patients were reevaluated at a mean of 30 months following surgery.

Results

Preoperative hearing function revealed American Academy of Otolaryngology–Head and Neck Surgery Foundation Classes A and B in 7 patients each, Class C in 4, and D in 9. Four patients presented with deafness. Hearing preservation was achieved in 10 patients (Classes A–C in 2 patients each, and Class D in 4 patients). Tumor removal was complete in all patients with hearing preservation, except for 2 patients with neurofibromatosis. In 4 patients a planned subtotal excision was performed due to the individual's age or underlying disease. In 1 patient a recurrent tumor was completely removed 3 years after the initial procedure.

Conclusions

The cochlear nerve in medial VSs requires special attention due to the atypical intracisternal growth pattern. Even in large tumors, hearing could be preserved in 37% of cases, since the cochlear nerve in medial schwannomas may not exhibit the adherence to the tumor capsule seen in tumors with comparable size involving the internal auditory canal.

Intraoperative brainstem auditory evoked potential pattern and perioperative vasoactive treatment for hearing preservation in vestibular schwannoma surgery

OBJECTIVE

In vestibular schwannoma surgery, four different intraoperative brainstem auditory evoked potential (BAEP) patterns (stable BAEP, abrupt loss, irreversible progressive loss, reversible loss) can be identified and correlated with postoperative hearing outcome. Patients with reversible loss significantly benefit from postoperative vasoactive treatment consisting of hydroxyethyl starch and nimodipine. The present study investigates the treatment effect in the remaining three BAEP patterns.

METHODS

A retrospective analysis was performed in 92 patients operated on for vestibular schwannoma between 1997 and 2005. Between 1997 and 2001, only patients with reversible loss of BAEP received vasoactive medication. Subsequently, all patients operated on between 2001 and 2005 received a 10 day course of therapy, regardless of the BAEP pattern. Serial audiological examinations before, after surgery and after 1 year were performed in all patients.

RESULTS

All 30 patients with reversible loss of BAEP received medication, and postoperative hearing preservation was documented in 21 patients. All 13 patients with stable waves showed hearing preservation, regardless of treatment. In all 24 patients with abrupt loss and in all 25 patients with irreversible progressive loss, postoperative anacusis was documented, regardless of treatment.

CONCLUSION

In patients with reversible loss of BAEP, a disturbed microcirculation of the cochlear nerve seems to be the underlying pathophysiological factor. In patients with abrupt or irreversible progressive loss, additional mechanical injury of nerve fibres determines hearing outcome. The study provides evidence that for the purpose of hearing preservation, only patients with reversible loss of BAEP benefit from vasoactive treatment.

Classification of neurovascular compression in typical hemifacial spasm: three-dimensional visualization of the facial and the vestibulocochlear nerves

Object

In this paper, the authors introduce a method of noninvasive anatomical analysis of the facial nerve–vestibulocochlear nerve complex and the depiction of the variable vascular relationships by using 3D volume visualization. With this technique, a detailed spatial representation of the facial and vestibulocochlear nerves was obtained. Patients with hemifacial spasm (HFS) resulting from neurovascular compression (NVC) were examined.

Methods

A total of 25 patients (13 males and 12 females) with HFS underwent 3D visualization using magnetic resonance (MR) imaging with 3D constructive interference in a steady state (CISS). Each data set was segmented and visualized with respect to the individual neurovascular relationships by direct volume rendering. Segmentation and visualization of the facial and vestibulocochlear nerves were performed with reference to their root exit zone (REZ), as well as proximal and distal segments including corresponding blood vessels. The 3D visualizations were interactively compared with the intraoperative situation during microvascular decompression (MVD) to verify the results with the observed microneurosurgical anatomy.

Results

Of the 25 patients, 20 underwent MVD (80%). Microvascular details were recorded on the affected and unaffected sides. On the affected sides, the anterior inferior cerebellar artery (AICA) was the most common causative vessel. The posterior inferior cerebellar artery, vertebral artery, internal auditory artery, and veins at the REZ of the facial nerve (the seventh cranial nerve) were also found to cause vascular contacts to the REZ of the facial nerve. In addition to this, the authors identified three distinct types of NVC within the REZ of the facial nerve at the affected sides. The authors analyzed the varying courses of the vessels on the unaffected sides. There were no bilateral clinical symptoms of HFS and no bilateral vascular compression of the REZ of the facial nerve. The authors discovered that the AICA is the most common vessel that interferes with the proximal and distal portions of the facial nerve without any contact between vessels and the REZ of the facial nerve on the unaffected sides.

Conclusions

Three-dimensional visualization by direct volume rendering of 3D CISS MR imaging data offers the opportunity of noninvasive exploration and anatomical categorization of the facial nerve–vestibulocochlear nerve complex. Furthermore, it proves to be advantageous in establishing the diagnosis and guiding neurosurgical procedures by representing original MR imaging patient data in a 3D fashion. This modality provides an excellent overview of the entire neurovascular relationship of the cerebellopontine angle in each case.

Inadequate medical treatment of patients with coronary artery disease by primary care physicians in Germany

AIMS

The DETECT study was performed to obtain representative data about the frequency, distribution, and treatment of patients with coronary artery disease (CAD) in the primary care setting in Germany.

METHODS AND RESULTS

The DETECT study was a cross-sectional clinical- epidemiological survey of a nationally representative sample of 3795 primary care offices and 55,518 patients. Overall, 12.4% of patients were diagnosed with CAD. Stable angina pectoris and myocardial infarction were the most frequent (4.2%) subgroups, followed by status post (s/p) percutaneous coronary interventions (PCI, 3.0%) and s/p coronary bypass surgery (2.2%). Patients with CAD were prescribed AT1 receptor antagonists (in 19.4% of cases), beta blockers (57.2%), ACE inhibitors (49.9%), antiplatelet agents (52.7%), statins (43.0%), and long-term nitrates (24.5%). When comparing all CAD patients with social health care insurance to those who had private insurance, private patients had significantly higher rates of revascularisation procedures and use of preventive medications.

CONCLUSION

Great potential remains for improving secondary prevention in primary care in Germany to reduce the risk of further coronary or vascular events, especially in patients with social health care insurance.

Vasoactive treatment for hearing preservation in acoustic neuroma surgery

OBJECT

Delayed hearing loss following surgery for acoustic neuroma indicates anatomical and functional preservation of the cochlear nerve and implies that a pathophysiological mechanism is initiated during surgery and continues thereafter. Intraoperative brainstem auditory evoked potentials (BAEPs) typically demonstrate gradual reversible loss of components in these patients.

METHODS

Based on this BAEP pattern, a consecutive series of 41 patients with unilateral acoustic neuromas was recruited into a prospective randomized study to investigate hearing outcomes following the natural postoperative course and recuperation after vasoactive medication. Both groups were comparable in patient age, tumor size, and preoperative hearing level. Twenty patients did not receive postoperative medical treatment. In 70% of these patients anacusis was documented and in 30% hearing was preserved. Twenty-one patients were treated with hydroxyethyl starch and nimodipine for an average of 9 days. In 66.6% of these patients hearing was preserved and in 33.3% anacusis occurred.

CONCLUSIONS

These results are statistically significant (p < 0.05, chi2 = 5.51) and provide evidence that these surgically treated patients suffer from a disturbed microcirculation that causes delayed hearing loss following removal of acoustic neuromas.

Clinical and neurophysiological observations after superior petrosal vein obstruction during surgery of the cerebellopontine angle: case report

IMPORTANCE

Preservation of venous drainage during surgery of the cerebellopontine angle has received little attention.

CLINICAL PRESENTATION

We describe changes in brainstem auditory evoked potentials after temporary obstruction of the superior petrosal vein during surgical resection of a small meningioma at the petrous apex via a standard suboccipital-lateral approach. Temporary clipping of the petrosal vein resulted in deterioration of the brainstem auditory evoked potentials. The tumor was removed with preservation of the superior petrosal vein.

CONCLUSION

A transient postoperative cochlear nerve deficit emphasizes the importance of venous drainage and its preservation during surgery for small lesions of the cerebellopontine angle that do not distort normal anatomic structures.

Contralateral hearing loss as an effect of venous congestion at the ipsilateral inferior colliculus after microvascular decompression: report of a case

Contralateral hearing loss after surgical procedures within the cerebellopontine angle is rarely seen and its pathophysiological background is not yet understood. A patient with contralateral hearing loss after microvascular decompression for trigeminal neuralgia is described. Ipsilateral brainstem auditory potential (BAEP) monitoring and facial nerve EMG did not show major abnormalities. During otherwise uneventful and successful surgery a branch of the petrosal vein was sacrificed to widen the access to the trigeminal root exit zone. On the third postoperative day the patient complained about contralateral hearing loss, which was verified by audiometry. Contralateral BAEPs showed low amplitudes and delayed interpeak latencies. Brain CT was normal. Brain MRI on the 8th postoperative day disclosed abnormal signals within the ipsilateral inferior colliculus. Intravenous heparinisation was performed and hearing slowly recovered over a 3 month period. Results from this patient offer a pathophysiological mechanism for contralateral hearing loss after cerebellopontine angle surgery, illustrate the importance of venous drainage preservation, gives evidence about the generation of BAEP components within the contralateral brainstem, and stresses the importance of intraoperative BAEP monitoring.

The prognostic value of intraoperative BAEP patterns in acoustic neurinoma surgery

Based on a consecutive series of 70 hearing patients with unilateral acoustic neurinomas and intraoperative monitoring of brain-stem auditory evoked potentials (BAEP), 4 dynamic BAEP patterns could be characterized. These patterns correspond with early and late postoperative hearing outcome. All patients with stable wave V (pattern 1) showed definite hearing preservation, all patients with irreversible abrupt loss of BAEP (pattern 2) lost their hearing, despite early hearing preservation in two cases. All patients with irreversible progressive loss of either wave I or wave V (pattern 3) eventually suffered from definite postoperative hearing loss, despite early hearing preservation in two cases. Those cases with intraoperative reversible loss of BAEP (pattern 4) showed variable short and long term hearing outcome. In 34% hearing was preserved, 44% suffered from postoperative hearing loss, the remaining 22% showed postoperative hearing fluctuation, either as a delayed hearing loss or as reversible hearing loss. Postoperative hearing fluctuation indicates anatomical and functional preservation of the cochlear nerve during surgery and is suggestive of a pathophysiological mechanism initiated during the surgical procedure and continuing thereafter. Patients at risk for delayed hearing loss can be identified during surgery by a characteristic BAEP pattern and may benefit from vasoactive treatment.

Integration of generic indicators for quality management in hospital information systems

Hospital information systems may contribute in different ways to quality management activities such as monitoring of quality indicators. Most existing quality management activities in hospitals are adjusted to a special medical field or particular disease. These activities often run simultaneously with other procedures and the documentation of patient care. To determine an interdisciplinary integrated quality management procedure, a pilot study was carried out at the Neurosurgery Department and Neonatology Division of the Medical Center of the University of Heidelberg. Predefined generic indicators that may be integrated in an existing information system and used in hospital routine were the basis of this project. The aim of the study was to support the quality management with periodic reports of these indicators. The pilot study showed that there were barriers along the path to an integrated generic quality management. To meet the requirements of routine monitoring, using predefined generic indicators of hospital care, much integration effort, directed at organizational aspects of information processing and information systems architecture, is still needed.

[Measuring intraocular pressure in keratoconus. Effect of the changed biomechanics]

BACKGROUND

Keratoconus is associated with changes in the corneal structure, such as defects of Bowman's layer, a decrease of corneal thickness etc. They result in alterations of some of the biomechanical parameters of the cornea, namely, rigidity and elasticity. The present study was performed to examine how impression tonometry and applanation tonometry for determination of intraocular pressure (IOP) are affected by the changed biomechanical parameters associated with keratoconus.

PATIENTS AND METHODS

We examined 20 normal subjects (40 eyes) and 17 keratoconus patients (25 eyes). The corneal thickness was measured by ultrasound pachymetry in the corneal center. In the keratoconus patients, an additional measurement was made at the conus peak. The corneal curvature was determined using the TMS keratoscope. The IOP measurements were made with the Schiötz tonometer (10 g). For comparison, additional IOP measurements in the corneal center and, in the keratoconus group, on the conus peak were made with the applanation tonometer.

RESULTS

The normal subjects had a central corneal thickness of 548 +/- 30 microns, compared to 505 +/- 42 microns in the corneal center and 425 +/- 41 microns on the conus peak in keratoconus patients. The average corneal curvature was 43.3 +/- 1.8 D in the normal subjects and 47.8 +/- 4.1 D in keratoconus patients. Applanation tonometry produced results on 11.33 +/- 1.43 mm Hg in the normal group (corneal center) compared to values of 12.00 +/- 2.55 mm Hg (corneal center) and 7.30 +/- 1.95 mm Hg (conus peak) in the keratoconus cohort. The coefficient of rigidity was 0.0236 +/- 0.0026 microliter-1 in the normal subjects, compared to 0.0173 +/- 0.0050 microliter-1 in the keratoconus patients.

CONCLUSION

The morphological changes associated with keratoconus may cause tonometry errors.