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1.
Anaesthesiologie ; 71(9): 689-696, 2022 09.
Article in German | MEDLINE | ID: mdl-35243526

ABSTRACT

BACKGROUND: The coronavirus pandemic caused a sudden change in medical education worldwide and induced a shift towards digital teaching. Previously, most courses were organized for students in physical presence on campus, while a few institutions already complemented these with blended learning methods, combining digital teaching with clinical presence; however, the use of digital teaching was heterogeneous, ranging from the use of PowerPoint slides to the application of virtual patients and telemedicine. OBJECTIVE: This study aimed to identify challenges and opportunities arising from the different tools used in digital teaching, such as recorded lectures or online seminars, and the role of hands-on clinical experience. In addition, the study examined student attitudes and experiences with the nearly all-digital semester beginning in spring 2020. These findings may help to better understand the impact of digital teaching on students and provide guidance on how to optimize digital medical teaching in the future. METHODS: A questionnaire with a 5-point Likert scale was developed to assess students' experiences with digital teaching at the onset of the COVID-19 pandemic in a cross-sectional study. The questionnaire was distributed to all medical students at the University of Mainz, Germany, who attended an anesthesiology course with asynchronously recorded lectures replacing traditional on-campus lectures during the pandemic. A total of 766 students in 4 courses met these criteria and received the online questionnaire for anonymous and voluntary response. RESULTS: A total number of 141 students responded, resulting in a response rate of 18.4%. Almost all students had access to the appropriate technology to participate in digital courses and 80.9% indicated seeing more recorded lectures compared to previous face-to-face lectures on campus. Moreover, 67.4% reported that they paused the asynchronous lectures to look up additional information and 95.7% stated that they appreciated the possibility to view lectures regardless of time and location. Hence, 84.3% said they would prefer digital lectures over face-to-face lectures in the future; however, 28.4% missed the interaction with teachers during lectures. Thus, 94.3% of the students appreciated the online seminars in terms of theoretical knowledge but the majority missed the practical aspects in the courses. Overall, 78.0% responded that the digital availability of material and digital teaching formats helped them to enhance their independent learning abilities. CONCLUSION: This study highlights several opportunities and challenges associated with digital teaching. The availability of prerecorded lectures at any time and place seems to facilitate access and increases student motivation. It also promotes individualization of student learning. Main disadvantages are the lack of communication with teachers and other students as well as the missing opportunity to reinforce the theoretical knowledge through application in practical courses, which, however, are essential for medical education. Therefore, a possible solution in the future could be the introduction of the "inverted classroom" concept, as it focuses on application and deepening of clinical skills in interactive classes, while the theoretical knowledge acquisition is taught in a digital teaching environment. The present study proposes the introduction of blended learning concepts to enhance the benefits of digital teaching while minimizing the identified disadvantages.


Subject(s)
Anesthesiology , COVID-19 , Students, Medical , COVID-19/epidemiology , Cross-Sectional Studies , Humans , Pandemics
2.
Anaesthesia ; 76(5): 647-654, 2021 05.
Article in English | MEDLINE | ID: mdl-33227153

ABSTRACT

Non-invasive haemoglobin measurement using absolute values lacks the precision to be the sole basis for the treatment of pre-operative anaemia. However, it can possibly serve as a screening test, indexing 'anaemia' with high sensitivity when values remain under prespecified cut-off values. Based on previous data, non-invasive haemoglobin cut-off values (146 g.l-1 for women and 152 g.l-1 for men) detect true anaemia with 99% sensitivity. An index test with these prespecified cut-off values was verified by prospective measurement of non-invasive and invasive haemoglobin pre-operatively in elective surgical patients. In 809 patients, this showed an estimated sensitivity (95%CI) of 98.9% (94.1-99.9%) in women and 96.4% (91.0-99.0%) in men. This saved invasive blood tests in 9% of female and 28% of male patients. In female patients, a lower non-invasive haemoglobin cut-off value (138 g.l-1 ) would save 28% of invasive blood tests with a sensitivity of 95%. The target 99% sensitivity would be reached by non-invasive haemoglobin cut-off values of 152 g.l-1 in female and 162 g.l-1 in male patients, saving 3% and 9% of invasive blood tests, respectively. Bias and limits of agreement between non-invasive and laboratory haemoglobin levels were 2 and - 25 to 28 g.l-1 , respectively. Patient and measurement characteristics did not influence the agreement between non-invasive and laboratory haemoglobin levels. Although sensitivity was very high, the index test using prespecified cut-off values just failed to reach the target sensitivity to detect true anaemia. Nevertheless, with respect to blood-sparing effects, the use of the index test in men may be clinically useful, while an index test with a lower cut-off (132 g.l-1 ) could be more clinically appropriate in women.


Subject(s)
Anemia/diagnosis , Hematologic Tests/methods , Hemoglobins/analysis , Adult , Aged , Anemia/surgery , Elective Surgical Procedures , Female , Humans , Male , Middle Aged , Preoperative Care , Prospective Studies , Sensitivity and Specificity
4.
J Neurol Surg A Cent Eur Neurosurg ; 78(5): 478-487, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28482371

ABSTRACT

The workshop of scientific medical faculties (Arbeitsgemeinschaft wissenschaftlicher medizinischer Fakultäten [AWMF]) of Germany has asked societies of specific medical disciplines to jointly publish guidelines on the treatment of diseases and injuries. On behalf of the Deutsche Gesellschaft für Neurochirurgie, its commission on guidelines initiated an interdisciplinary approach to publish guidelines on the treatment of head injury in adults. These guidelines were published in German by the AWMF in late 2015. Because these guidelines have received widespread attention in Germany and became fundamental for research in head injuries, we have translated the German version into English to make it accessible to the international scientific community.


Subject(s)
Craniocerebral Trauma/therapy , Adult , Germany , Humans
5.
Br J Anaesth ; 117(4): 482-488, 2016 Oct.
Article in English | MEDLINE | ID: mdl-28077536

ABSTRACT

BACKGROUND: Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output. METHODS: Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS® and FORE-SIGHT®. Cardiac output was measured at eight predefined time points using transoesophageal echocardiography. RESULTS: Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS® was 70 (sd 9)%; thereafter, it increased by 0.0187% min-1 (P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT® started at 68 (sd 13)% and increased by 0.0142% min-1 (P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min-1 at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation. CONCLUSIONS: During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant. CLINICAL TRIAL REGISTRATION: NCT01275898.


Subject(s)
Anesthesia , Brain/metabolism , Cardiac Output , Neurosurgical Procedures , Oxygen/metabolism , Patient Positioning , Adult , Aged , Arterial Pressure , Female , Humans , Male , Middle Aged , Prospective Studies
6.
Anaesthesist ; 65(2): 151-60; quiz 161, 2016 Feb.
Article in German | MEDLINE | ID: mdl-26696267

ABSTRACT

Anesthesiological challenges during craniotomy result from the anatomically related low compensatory capacity of the intracranial space in response to increased volume and the low ischemic tolerance of brain tissue. The anesthetic agents used should therefore not increase the intracranial volume and improve the ischemic tolerance. An acute life-threatening increase of intracranial pressure can be temporarily treated by hyperventilation until measures, such as osmotherapy and infusion of intravenous anesthetics become effective. During an operation the homeostatic parameters including blood volume, blood pressure, partial pressure of carbon dioxide and oxygen in blood, plasma glucose concentration and core body temperature have to be closely monitored and kept normal (6 Ns). Optimal implementation of anesthesia necessitates a detailed knowledge of the surgical approach and potential complications. Postoperatively, patients should be extubated as soon as possible to closely monitor cognitive function so that potential deterioration can be detected.


Subject(s)
Anesthesia/methods , Anesthesiology/methods , Neurosurgery/methods , Brain Edema/therapy , Craniotomy/methods , Humans , Neurosurgical Procedures , Perioperative Care
7.
Anaesthesia ; 69(9): 1009-22, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24829066

ABSTRACT

Various experimental studies in animals have shown that general anaesthetics are potentially toxic to the developing brain. By inducing apoptosis or interfering with neurogenesis, anaesthetic exposure during a critical period of neuronal development can have significant impact on neurocognitive function later in life. It remains controversial whether these experimental results can be transferred to human beings and this is under intensive scientific evaluation. To gain more insight into possible neurotoxic effects on the human brain of infants and small children, a number of retrospective studies have been performed. At present, there is no clear evidence that exposure to anaesthesia up to the age of 3-4 years is associated with neurocognitive or behavioural deficits. Currently, the PANDA, MASK and GAS studies are underway to explore this relationship. Anaesthesia is not an end in itself, but necessary to facilitate surgical procedures. There is evidence that maintaining physiological conditions is important for the overall outcome following anaesthesia and surgery. Until proven otherwise, it can be recommended to keep anaesthesia and surgery as short as possible, to use short-acting drugs and/or a combination of general anaesthesia and multimodal pain therapy including systemic analgesics, and local or regional anaesthesia, to reduce the overall drug dosage.


Subject(s)
Anesthesia, General/adverse effects , Anesthetics, General/adverse effects , Brain/growth & development , Anesthesia, Conduction , Anesthetics, General/administration & dosage , Anesthetics, General/toxicity , Animals , Brain/drug effects , Child , Child, Preschool , Cognition/drug effects , Humans , Infant , Infant, Newborn , Nerve Degeneration/chemically induced , Nerve Degeneration/pathology , Neurotoxicity Syndromes
8.
Anaesthesia ; 69(1): 58-63, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24256501

ABSTRACT

Trendelenburg positioning in combination with pneumoperitoneum during robotic-assisted prostatic surgery possibly impairs cerebrovascular autoregulation. If cerebrovascular autoregulation is disturbed, arterial hypertension might induce cerebral hyperaemia and brain oedema, while low arterial blood pressure can induce cerebral ischaemia. The time course of cerebrovascular autoregulation was investigated during use of the Trendelenburg position and a pneumoperitoneum for robotic-assisted prostatic surgery using transcranial Doppler ultrasound. Cerebral blood flow velocity was correlated with arterial blood pressure and the autoregulation index (Mx) was calculated. In 23 male patients, Mx was assessed at baseline, after induction of general anaesthesia, during the Trendelenburg position (40-45°), and after repositioning. During the Trendelenburg position, Mx increased over time, indicating an impairment of cerebrovascular autoregulation. After repositioning, Mx recovered to baseline levels. It can be concluded that with longer durations of Trendelenburg position and pneumoperitoneum, cerebrovascular autoregulation deteriorates, and, therefore, blood pressure management should be adapted to avoid cerebral oedema and the duration of Trendelenburg position should be as short as possible.


Subject(s)
Cerebrovascular Circulation/physiology , Head-Down Tilt/physiology , Prostatectomy/methods , Robotics/methods , Aged , Blood Flow Velocity/physiology , Blood Pressure/physiology , Brain Edema/etiology , Brain Edema/prevention & control , Head-Down Tilt/adverse effects , Homeostasis/physiology , Humans , Male , Middle Aged , Middle Cerebral Artery/diagnostic imaging , Middle Cerebral Artery/physiopathology , Monitoring, Intraoperative/methods , Patient Positioning/adverse effects , Patient Positioning/methods , Pneumoperitoneum, Artificial/adverse effects , Prospective Studies , Time Factors , Ultrasonography, Doppler, Transcranial/methods
9.
Anaesthesist ; 62(2): 91-100, 2013 Feb.
Article in German | MEDLINE | ID: mdl-23392218

ABSTRACT

Many animal experiments have shown that anesthetics can have a neurotoxic effect on immature brains because they induce apoptosis and influence neurogenesis and synaptogenesis. In animal experiments this has substantial implications for the neurocognitive functions of animals in later life. Whether these results of animal experiments can be transferred to humans is currently the subject of intensive research. In several retrospective studies no clear association between anesthesia in premature babies, newborns or infants and the occurrence of learning disorders or behavioral problems could be found. The prospective studies GAS and PANDA are designed to obtain a deeper insight and if possible to clarify this problem. Because of the high relevance of this topic and in order to achieve more clarity for this problem when dealing with parents, the scientific working group for neuroanesthesia and pediatric anesthesia of the German Society for Anesthesiology and Intensive Care Medicine (DGAI) has formulated a position document on the basis of currently available data.


Subject(s)
Anesthetics, General/adverse effects , Neurotoxicity Syndromes/physiopathology , Anesthetics, General/pharmacology , Anesthetics, General/toxicity , Animals , Apoptosis/drug effects , Child, Preschool , Dose-Response Relationship, Drug , Drug Combinations , Female , Humans , Infant , Infant, Newborn , Infant, Premature , Male , Nerve Degeneration/chemically induced , Nerve Degeneration/pathology , Neurons/drug effects , Neuroprotective Agents/pharmacology , Neurotoxicity Syndromes/diagnosis
11.
Acta Anaesthesiol Scand ; 57(3): 320-5, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23167550

ABSTRACT

BACKGROUND: Cyclic alveolar recruitment and derecruitment play a role in the pathomechanism of acute lung injury and may lead to arterial partial pressure of oxygen (PaO(2) ) oscillations within the respiratory cycle. It remains unknown, however, if these PaO(2) oscillations are transmitted to the microcirculation. The present study investigates if PaO(2) oscillations can be detected in the pig buccal mucosa microcirculation. METHODS: Respiratory failure was induced by surfactant depletion in seven pigs. PaO(2) oscillations caused by cyclic recruitment and derecruitment were measured in the thoracic aorta by fast fluorescence quenching of oxygen technology. Haemoglobin oxygen saturation, haemoglobin amount and blood flow in the buccal mucosa microcirculation were determined by combined fast white light spectrometry and laser Doppler flowmetry additionally to systolic arterial pressure. Measurements were performed during baseline conditions and during cyclic recruitment and derecruitment. RESULTS: Measurements remained stable during baseline. Respiratory-dependent oscillations occurred in the systemic circulation [PaO(2) oscillations 92 (69-172) mmHg; systolic arterial pressure oscillations 33 (13-35) %] and were related to the respiratory rate (5.0 ± 0.2/min) as confirmed by Fourier analysis. Synchronised oscillations were detected to the pig buccal mucosa microcirculation [haemoglobin oxygen saturation oscillations 3.4 (2.7-4.9) %; haemoglobin amount oscillations 8.5 (2.3-13.3) %; blood flow oscillations 66 (18-87) %]. The delay between PaO(2) -\ and microcirculatory oxygen oscillations was 7.2 ± 2.8 s. CONCLUSION: The present study suggests that PaO(2) oscillations caused by cyclic recruitment and derecruitment were transmitted to the buccal mucosa microcirculation. This non-invasive approach of measuring oxygen waves as a surrogate parameter of cyclic recruitment and derecruitment could be used to monitor PaO(2) oscillations at the bedside.


Subject(s)
Cheek/blood supply , Oxygen/blood , Pulmonary Alveoli/physiology , Animals , Aorta, Thoracic/physiology , Arterial Pressure , Bronchoalveolar Lavage , Fourier Analysis , Hemodynamics/physiology , Laser-Doppler Flowmetry , Microcirculation/physiology , Monitoring, Physiologic , Pulmonary Gas Exchange , Regional Blood Flow/physiology , Respiratory Insufficiency/physiopathology , Swine
12.
Br J Anaesth ; 110(2): 266-73, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23103776

ABSTRACT

BACKGROUND: Cyclic recruitment and derecruitment (R/D) play a key role in the pathomechanism of acute lung injury (ALI) leading to respiration-dependent oscillations of arterial partial pressure of oxygen (Pa(O(2))). These Pa(O(2)) oscillations could also be forwarded to the cerebral microcirculation. METHODS: In 12 pigs, partial pressure of oxygen was measured in the thoracic aorta (Pa(O(2))) and subcortical cerebral tissue (Pbr(O(2))). Cerebral cortical haemoglobin oxygen saturation (Sbr(O(2))), cerebral blood flow (CBF), and peripheral haemoglobin saturation (Sp(O(2))) were assessed by spectroscopy and laser Doppler flowmetry. Measurements at different fractions of inspired oxygen (F(I(O(2)))) were performed at baseline and during cyclic R/D. STATISTICS: frequency domain analysis, the Mann-Whitney test, linear models to test the influence of Pa(O(2)) and systolic arterial pressure (SAP) oscillations on cerebral measurements. RESULTS: Parameters [mean (SD)] remained stable during baseline. Pa(O(2)) oscillations [10.6 (8) kPa, phase(reference)], systemic arterial pressure (SAP) oscillations [20 (9) mm Hg, phase(Pa(O(2))-SAP) -33 (72)°], and Sp(O(2))oscillations [1.9 (1.7)%, phase(Pa(O(2))-Sp(O(2))) 264 (72)°] were detected during lung R/D at 1.0. Pa(O(2)) oscillations decreased [2.7 (3.5) kPa, P=0.0008] and Sp(O(2)) oscillations increased [6.8 (3.9)%, P=0.0014] at F(I(O(2))) 0.3. In the brain, synchronized Pbr(O(2)) oscillations [0.6 (0.4) kPa, phase(Pa(O(2))-Pbr(O(2))) 90 (39)°], Sbr(O(2)) oscillations [4.1 (1.5)%, phase(Pa(O(2))-Sbr(O(2))) 182 (54)°], and CBF oscillations [198 (176) AU, phase(Pa(O(2))-CBF) 201 (63)°] occurred that were dependent on Pa(O(2)) and SAP oscillations. CONCLUSIONS: Pa(O(2)) oscillations caused by cyclic R/D are transmitted to the cerebral microcirculation in a porcine model of ALI. These cyclic oxygen alterations could play a role in the crosstalk of acute lung and brain injury.


Subject(s)
Acute Lung Injury/complications , Acute Lung Injury/physiopathology , Cerebrovascular Circulation/physiology , Lung/physiopathology , Microcirculation/physiology , Oxygen/blood , Anesthesia, General , Animals , Blood Gas Monitoring, Transcutaneous , Blood Pressure/drug effects , Bronchoalveolar Lavage Fluid , Craniotomy , Hemodynamics/physiology , Laser-Doppler Flowmetry , Respiration, Artificial , Swine , Ventilators, Mechanical
14.
Br J Anaesth ; 107(5): 735-41, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21862494

ABSTRACT

BACKGROUND: Propofol reduces cerebral blood flow (CBF) secondary to cerebral metabolic depression. However, in vitro and in vivo studies demonstrate that propofol directly dilates the vascular smooth muscle. This study investigates the effects of propofol-induced changes in bispectral index (BIS) on cerebral microcirculation and oxygenation during craniotomies. METHODS: In 21 craniotomy patients undergoing routine craniotomy, anaesthesia was maintained with propofol 4-10 mg kg⁻¹ h⁻¹ and remifentanil 0.1-0.4 µg kg⁻¹ min⁻¹. Propofol concentration was adjusted to achieve higher BIS (target 40) or lower BIS (target 20). Regional measurements of capillary venous blood flow (rvCBF), oxygen saturation (srvO2), and haemoglobin amount (rvHb) at 2 mm (grey matter) and 8 mm (white matter) cerebral depth were randomly performed at higher and lower BIS by combined laser-Doppler flowmetry and spectroscopy. Calculations: approximated arteriovenous difference in oxygen content (avDO2) and cerebral metabolic rate of oxygen (aCMRO2). RESULTS: mean values (sd). STATISTICS: Mann-Whitney test (*P<0.05). Results Human cerebral microcirculation and oxygen saturation were assessed at propofol dosages 5.1 (2.3) mg kg⁻¹ h⁻¹ [BIS 40 (9)] and 7.8 (2.1) mg kg⁻¹ h⁻¹ [BIS 21 (7)]. Propofol-induced reduction in BIS resulted in increased srvO2 (P=0.018), and decreased avDO2 (P=0.025) and aCMRO(2) (P=0.022), in 2 mm cerebral depth, while rvCBF and rvHb remained unchanged. In 8 mm cerebral depth, srvO2, rvCBF, rvHb, and also calculated parameters avDO2 and aCMRO2 remained unaltered. CONCLUSIONS: Findings suggest alteration of the CBF/CMRO2 ratio by propofol in cortical brain regions; therefore, it might be possible that propofol affects coupling of flow and metabolism in the cerebral microcirculation.


Subject(s)
Anesthetics, Intravenous/pharmacology , Cerebrovascular Circulation/drug effects , Microcirculation/drug effects , Monitoring, Intraoperative/methods , Oxygen/metabolism , Propofol/pharmacology , Adult , Anesthetics, Intravenous/metabolism , Brain/blood supply , Brain/drug effects , Brain/metabolism , Consciousness Monitors , Craniotomy , Dose-Response Relationship, Drug , Female , Hemoglobins/drug effects , Hemoglobins/metabolism , Humans , Laser-Doppler Flowmetry/methods , Male , Middle Aged , Oximetry/methods , Piperidines , Propofol/metabolism , Remifentanil , Spectrum Analysis/methods
15.
Radiologe ; 51(7): 596-601, 2011 Jul.
Article in German | MEDLINE | ID: mdl-21559925

ABSTRACT

Magnetic resonance imaging (MRI) is the method of choice in staging endometrial cancer. Using MRI early tumor invasion (stage IA) can be differentiated from a deep tumor growth (stage IB) of the myometrium with reported sensitivities of 85-95%.Tumor invasion of the uterine cervix can be depicted with a sensitivity of 80% and specificity of 96%. In demonstrating lymph node metastases MRI shows a sensitivity of 50%, a specificity of 95% and and accuracy of 90%. These diagnostic criteria are decisive for the choice of therapy procedures. So a simple hysterectomy will be performed in early stage IA disease while an extended surgical procedure with pelvic lymphadenectomy and radiotherapy will be considered in advanced stages IB and II disease. Vaginal ultrasound shows lower values in tumor staging with accuracies of 73-95%. Staging accuracies of computed tomography also show lower results with 61-76%. For planning radiotherapy and detection of cancer recurrence MRI is the most valuable tool.


Subject(s)
Endometrial Neoplasms/diagnosis , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Ultrasonography/methods , Female , Humans
16.
Prostate Cancer Prostatic Dis ; 13(1): 65-70, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19752886

ABSTRACT

The purpose of this study is to report our method in detecting prostate cancer (PCa) using an 18-core transrectal ultrasound (TRUS) prostate biopsy (PB) schema, in combination with additional targeted cores from suspicious images in conventional (e-cMRI) and functional (e-fMRI) endorectal magnetic resonance imaging (e-MRI) of the prostate. From 2004 to 2008, 260 consecutive patients with a clinical suspicion of PCa underwent PB and were prospectively studied. e-cMRI and e-fMRI was performed in all patients before PB. The patients were divided into two groups (A and B) according to the results of their radiological findings (group A=suspicious findings, group B=non-suspicious findings). After the images were processed, an 18-core TRUS-guided PB was performed. When a patient exhibited a suspicious site on e-cMRI and e-fMRI images, three additional targeted PBs were obtained from that site. In group A, 17.5% of PCa was detected by the 18-core PB and 56.5% of PCa was detected by the targeted cores. The overall PCa detection rate (18+targeted cores) was 73.9%. The overall specificity was 73.9%. In group B, overall false-positive detection rate reached 19.2%, with the overall sensitivity being 80.8%. The method described above is not only practical but also a promising modality in PCa detection. As seen, PCa was optimally detected when combining the 18-core and targeted-core PB schema together. Non-suspicious images do not rule out the probability of PCa, thus justifying a PB in these patients as well.


Subject(s)
Magnetic Resonance Imaging/methods , Prostate/pathology , Prostatic Neoplasms/diagnosis , Ultrasound, High-Intensity Focused, Transrectal/methods , Aged , Biopsy, Needle/methods , False Positive Reactions , Humans , Male , Middle Aged , Prospective Studies , Prostate/diagnostic imaging , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/pathology , Sensitivity and Specificity , Ultrasonography
17.
Br J Anaesth ; 104(2): 224-7, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20031951

ABSTRACT

BACKGROUND: Laparoscopic interventions in children gain increasing popularity. Pneumoperitoneum as applied during laparoscopic surgery can induce gas emboli formation, but it is unclear whether this is associated with cerebral embolic events. To investigate the hypothesis that pneumoperitoneum causes cerebral emboli in children, the number and intensity of high-intensity transient signals (HITS) detected using transcranial Doppler ultrasonography were assessed before and after induction of pneumoperitoneum. METHODS: Twenty children were monitored during laparoscopic surgery. General anaesthesia was performed using sevoflurane and sufentanil or alfentanil. Pressure-controlled ventilation was adapted to maintain end-tidal Pco(2) (Pe'(co(2))) between 4.7 and 6.0 kPa. Baseline measurement of HITS rate, cerebral blood flow velocity, and mean arterial pressure (MAP) were recorded during steady-state anaesthesia before skin incision and during pneumoperitoneum with intra-abdominal pressure of 1.6-2.0 kPa applied using CO(2). RESULTS: In 14 children (70%), HITS were detected during baseline and pneumoperitoneum. Three additional children (15%) developed HITS during pneumoperitoneum only and another three children (15%) presented no HITS during the investigation period. MAP and cerebral blood flow velocity increased with pneumoperitoneum. CONCLUSIONS: HITS are present in 70% of paediatric surgical patients under balanced anaesthesia before surgical interventions. Pneumoperitoneum further increased the occurrence of HITS.


Subject(s)
Intracranial Embolism/etiology , Intraoperative Complications/diagnostic imaging , Laparoscopy/adverse effects , Pneumoperitoneum, Artificial/adverse effects , Blood Flow Velocity , Blood Pressure , Cerebrovascular Circulation , Child , Child, Preschool , Female , Humans , Infant , Intracranial Embolism/diagnostic imaging , Male , Ultrasonography, Doppler, Transcranial
18.
Acta Anaesthesiol Scand ; 53(6): 774-82, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19388889

ABSTRACT

BACKGROUND: The volatile anesthetic sevoflurane exhibits neuroprotective properties when assessed for motor function and histopathology after cerebral ischemia in rats. Damage of hippocampal neurons after ischemia relates to a number of cognitive deficits that are not revealed by testing animals for motor function. Therefore, the present study evaluates cognitive and behavioral function as well as hippocampal damage in rats subjected to cerebral ischemia under sevoflurane compared with fentanyl/nitrous oxide (N(2)O)/O(2) anesthesia. METHODS: Thirty-four rats were trained for 10 days using a hole-board test to detect changes in cognitive and behavioral function. Rats were randomly assigned to the following groups: (A) sham/fentanyl/N(2)O/O(2) (n=7); (B) ischemia/fentanyl/N(2)O/O(2) (n=10); (C) sham/2.0 vol% sevoflurane in O(2)/air (n=7); and (D) ischemia/2.0 vol% sevoflurane in O(2)/air (n=10). Cerebral ischemia was produced by unilateral common carotid artery occlusion combined with hemorrhagic hypotension (mean arterial blood pressure 40 mmHg for 45 min). Temperature, arterial blood gases, and pH were maintained constant. Cerebral blood flow was measured using laser-Doppler flowmetry. After surgery, cognitive and behavioral function was re-evaluated for 10 days. On day 11, the brains were removed for histopathologic evaluation (hematoxylin/eosin-staining). RESULTS: Cognitive testing revealed deficits in declarative and working memory in ischemic rats anesthetized with fentanyl/N(2)O. Rats anesthetized with sevoflurane during ischemia showed a significantly better outcome. Hippocampal damage was significantly worse with fentanyl/N(2)O. CONCLUSION: The present data add to previous investigations showing that sevoflurane prevents a deficit in cognitive function and histopathological damage induced by cerebral ischemia in rats.


Subject(s)
Anesthetics/therapeutic use , Brain Ischemia/complications , Cognition Disorders/drug therapy , Cognition Disorders/etiology , Methyl Ethers/therapeutic use , Psychomotor Performance/drug effects , Anesthesia , Anesthetics, Intravenous/pharmacology , Animals , Blood Gas Analysis , Brain/pathology , Brain Ischemia/pathology , Cognition Disorders/pathology , Data Interpretation, Statistical , Fentanyl/pharmacology , Immunohistochemistry , Male , Nitrous Oxide/pharmacology , Rats , Rats, Sprague-Dawley , Sevoflurane
20.
Acta Anaesthesiol Scand ; 53(4): 528-33, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19317867

ABSTRACT

BACKGROUND: Ketamine is a non-competitive antagonist at N-methyl-D-aspartate (NMDA) receptors and reduces neuronal injury after cerebral ischemia by blocking the excitotoxic effects of glutamate. However, cerebral regeneration by means of endogenous neurogenesis may be impaired with blockade of NMDA receptors. The effects of S(+) ketamine on post-ischemic neurogenesis are unknown and investigated in this study. METHODS: Thirty-two male Sprague-Dawley rats were randomly assigned to the following treatment groups with intravenous S(+) ketamine anesthesia: S(+) ketamine 0.75 mg/kg/min with or without cerebral ischemia and S(+) ketamine 1.0 mg/kg/min with or without cerebral ischemia. Eight non-anesthetized, non-ischemic animals were investigated as naïve controls. Forebrain ischemia was induced by bilateral common carotid artery occlusion in combination with hemorrhagic hypotension. 5-bromo-2-deoxyuridine (BrdU) was injected intraperitoneally for seven consecutive post-operative days. BrdU-positive neurons in the dentate gyrus and histopathological damage of the hippocampus were analyzed after 28 days. RESULTS: The number of new neurons was not affected by S(+) ketamine in the absence of cerebral ischemia. The ischemia-induced increase in neurogenesis was reduced by high-dose S(+) ketamine. Cell death of ischemic animals did not vary between low- and high-dose S(+) ketamine. CONCLUSION: While low concentrations of S(+) ketamine allow an ischemia-induced increase in the number of new neurons, high S(+) ketamine concentrations block the post-ischemic increase in newly generated neurons. This effect is irrespective of the extent of other histopathological damage and in line with studies showing that NMDA receptor antagonists like MK-801 inhibit neurogenesis after cerebral ischemia.


Subject(s)
Brain Ischemia/physiopathology , Excitatory Amino Acid Antagonists/pharmacology , Ketamine/pharmacology , Neurogenesis/drug effects , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Animals , Brain Ischemia/pathology , Dose-Response Relationship, Drug , Male , Rats , Rats, Sprague-Dawley
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