Perioperative red blood cell transfusion is associated with poor functional outcome and overall survival in patients with newly diagnosed glioblastoma.

The influence of perioperative red blood cell (RBC) transfusion on prognosis of glioblastoma patients continues to be inconclusive. The aim of the present study was to evaluate the association between perioperative blood transfusion (PBT) and overall survival (OS) in patients with newly diagnosed glioblastoma. Between 2013 and 2018, 240 patients with newly diagnosed glioblastoma underwent surgical resection of intracerebral mass lesion at the authors' institution. PBT was defined as the transfusion of RBC within 5 days from the day of surgery. The impact of PBT on overall survival was assessed using Kaplan-Meier analysis and multivariate regression analysis. Seventeen out of 240 patients (7%) with newly diagnosed glioblastoma received PBT. The overall median number of blood units transfused was 2 (95% CI 1-6). Patients who received PBT achieved a poorer median OS compared to patients without PBT (7 versus 18 months; p < 0.0001). Multivariate analysis identified "age > 65 years" (p < 0.0001, OR 6.4, 95% CI 3.3-12.3), "STR" (p = 0.001, OR 3.2, 95% CI 1.6-6.1), "unmethylated MGMT status" (p < 0.001, OR 3.3, 95% CI 1.7-6.4), and "perioperative RBC transfusion" (p = 0.01, OR 6.0, 95% CI 1.5-23.4) as significantly and independently associated with 1-year mortality. Perioperative RBC transfusion compromises survival in patients with glioblastoma indicating the need to minimize the use of transfusions at the time of surgery. Obeying evidence-based transfusion guidelines provides an opportunity to reduce transfusion rates in this population with a potentially positive effect on survival.

Tumor-associated epilepsy in patients with brain metastases: necrosis-to-tumor ratio forecasts postoperative seizure freedom.

Surgical resection is highly effective in the treatment of tumor-related epilepsy (TRE) in patients with brain metastases (BM). Nevertheless, some patients suffer from postoperative persistent epilepsy which negatively impacts health-related quality of life. Therefore, early identification of patients with potentially unfavorable seizure outcome after BM resection is important. Patients with TRE that had undergone surgery for BM at the authors' institution between 2013 and 2018 were analyzed with regard to preoperatively identifiable risk factors for unfavorable seizure outcome. Tumor tissue and tumor necrosis ratios were assessed volumetrically. According to the classification of the International League Against Epilepsy (ILAE), seizure outcome was categorized as favorable (ILAE 1) and unfavorable (ILAE 2-6) after 3 months in order to avoid potential interference with adjuvant cancer treatment. Among all 38 patients undergoing neurosurgical treatment for BM with concomitant TRE, 34 patients achieved a favorable seizure outcome (90%). Unfavorable seizure outcome was significantly associated with larger tumor volumes (p = 0.012), a midline shift > 7 mm (p = 0.025), and a necrosis/tumor volume ratio > 0.2 (p = 0.047). The present study identifies preoperatively collectable risk factors for unfavorable seizure outcome in patients with BM and TRE. This might enable to preselect for highly vulnerable patients with postoperative persistent epilepsy who might benefit from accompanying neuro-oncological expertise during further systemical treatment regimes.

Characterization of Transverse Aortic Constriction in Mice Based on the Specific Recruitment of Leukocytes to the Hypertrophic Myocardium and the Aorta Ascendens.

Transverse aortic constriction (TAC) is a model that mimics pressure overload-induced left ventricular (LV) hypertrophy in mice. Alterations in immune cell functionality can promote cardiac and vascular remodeling. In the present study, we characterized the time course in innate immune cell dynamics in response to TAC in the different tissues of mice. It was determined whether TAC induces a characteristic leukocyte-driven immune response in the myocardium, aorta ascendens and descendens, spleen, blood, and draining lymph nodes supported by cytokine-driven chemotaxis in mice at 3, 6, and 21 days following surgery. We used complex flow cytometry staining combinations to characterize the various innate immune cell subsets and a multiplex array to determine cytokine concentrations in the serum. The results of the current study indicated that leukocytes accumulate in the myocardium and aorta ascendens in response to TAC. The leukocyte dynamics in the myocardium were dominated by the Ly6Clow macrophages with an early accumulation, whereas the response in the aorta ascendens was characterized by a long-lasting proinflammatory phenotype driven by Ly6Chigh macrophages, neutrophils, and activated DCs. In contrast to the high-pressure environment of the aorta ascendens, the tissue of the aorta descendens did not react to TAC with any leukocyte increase. The levels of proinflammatory cytokines in the blood were elevated in response to TAC, indicating a systemic reaction. Moreover, our findings strongly suggest that cardiac macrophages could origin from splenic pools and reach the site of the inflammation via the blood. Based on the current findings, it can be concluded that the high-pressure conditions in the aorta ascendens cause a characteristic immune response, dominated by the accumulation of leukocytes and the activation of DCs that varies in comparison to the immune cell dynamics in the myocardium and the aorta descendens.

Changes in PUFA and eicosanoid metabolism during/after apnea diving: a prospective single-center study.

Background: The popularity of apneic diving is continually growing. As apnea diving substantially burdens the cardiovascular system, special focus is warranted. Regarding inflammation processes and associated inflammatory-related diseases (e.g., cardiovascular diseases), eicosanoids play an important role. This study aims to investigate polyunsaturated fatty acids (PUFAs) and eicosanoids in voluntary apnea divers, and so to further improve understanding of pathophysiological processes focusing on proinflammatory effects of temporarily hypercapnic hypoxia.. Methods: The concentration of PUFAs and eicosanoids were investigated in EDTA plasma in apnea divers (n=10) before and immediately after apnea, 0.5 hour and four hours later, applying liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Mean age was 41±10 years, and divers performed a mean breath-hold time of 317±111 seconds. PUFAs, eicosanoids and related lipids could be classified in four different kinetical reaction groups following apnea. The first group (e.g., Ω-6 and Ω-3-PUFAs) showed an immediate concentration increase followed by a decrease below baseline four hours after apnea. The second group (e.g., thromboxane B2) showed a slower increase, with its maximum concentration 0.5 hour post-apnea followed by a decrease four hours post-apnea. Group 3 (9- and 13-hydroxyoctadecadienoic acid) is characterized by two concentration increase peaks directly after apnea and four hours afterward compared to baseline. Group 4 (e.g., prostaglandin D2) shows no clear response. Conclusion: Changes in the PUFA metabolism after even a single apnea revealed different kinetics of pro- and anti-inflammatory regulations and changes for oxidative stress levels. Due to the importance of these mediators, apnea diving should be evaluated carefully and be performed only with great caution against the background of cardiovascular diseases and inflammation processes.

Myocardial maladaptation to pressure overload in CB2 receptor-deficient mice.

BACKGROUND: Adaptation to aortic valve stenosis leads to myocardial hypertrophy, which has been associated with inflammation, fibrosis and activation of the endocannabinoid system. Since the endocannabinoid system and the CB2 receptor provide cardioprotection and modulate immune response in experimental ischemia, we investigated the role of CB2 in a mouse model of cardiac pressure overload. METHODS: Transverse aortic constriction was performed in CB2 receptor-deficient (Cnr2-/-) mice and their wild-type littermates (Cnr2+/+). After echocardiography and Millar left heart catheter hemodynamic evaluation hearts were processed for histological, cellular and molecular analyses. RESULTS: The endocannabinoid system showed significantly higher anandamide production and CB2 receptor expression in Cnr2+/+ mice. Histology showed non-confluent, interstitial fibrosis with rare small areas of cardiomyocyte loss in Cnr2+/+ mice. In contrast, extensive cardiomyocyte loss and confluent scar formation were found in Cnr2-/- mice accompanied by significantly increased apoptosis and left ventricular dysfunction when compared with Cnr2+/+ mice. The underlying cardiac maladaptation in Cnr2-/- mice was associated with significantly reduced expression of myosin heavy chain isoform beta and less production of heme oxygenase-1. Cnr2-/- hearts presented after 7 days with stronger proinflammatory response including significantly higher TNF-alpha expression and macrophage density, but lower density of CD4+ and B220+ cells. At the same time, we found increased apoptosis of macrophages and adaptive immune cells. Higher myofibroblast accumulation and imbalance in MMP/TIMP-regulation indicated adverse remodeling in Cnr2-/- mice. CONCLUSIONS: Our study provides mechanistic evidence for the role of the endocannabinoid system in myocardial adaptation to pressure overload in mice. The underlying mechanisms include production of anandamide, adaptation of contractile elements and antioxidative enzymes, and selective modulation of immune cells action and apoptosis in order to prevent the loss of cardiomyocytes.

Cerebral white matter lesion burden is associated with the degree of aortic valve calcification and predicts peri-procedural cerebrovascular events in patients undergoing transcatheter aortic valve implantation (TAVI).

OBJECTIVES: To investigate the impact of aortic valve calcification and brain morphology on acute peri-procedural cerebrovascular events (CVEs) in patients undergoing transcatheter aortic valve implantation (TAVI). BACKGROUND: Aortic valve calcification and stenosis can be assessed with echocardiography. Cerebral magnetic resonance imaging (MRI) depicts and quantifies morphological signs of hypoperfusion and vascular embolism, which is of special interest in patients with severe aortic stenosis. Furthermore, subjects who undergo TAVI are prone to suffer of clinically silent peri-procedural CVEs. METHODS: A total of 119 patients referred to TAVI were investigated for aortic valve calcification using trans-esophageal echocardiography. Cerebral MRI prior to and immediate after implantation was performed in all patients using a dedicated scan protocol. Prior to TAVI, brain morphology was characterized. Post TAVI, brains were investigated for the onset of acute peri-procedural CVEs using diffusion weighted imaging (DWI). RESULTS: Seventy-eight patients (65.5%) revealed acute peri-procedural CVEs on MRI after TAVI with a favor of the left hemisphere (57.5%). The degree of valve calcification was associated with peri-procedural CVEs. Patients with a high WML burden had an increased risk for CVEs ((OR) 2.36 (95% CI: 1.09-5.15; P = 0.037)), especially when distributed periventricular ((OR: 3.27; 95% CI: 1.47-7.26; P = 0.0038)). CONCLUSION: In patients undergoing TAVI, the degree of aortic valve calcification and periventricular WML burden were correlated with acute peri-procedural CVEs. Future studies are needed to evaluate their independent value for the long-term clinical outcome.

Influence of Apnea-induced Hypoxia on Catecholamine Release and Cardiovascular Dynamics.

Prolonged breath-hold causes complex compensatory mechanisms such as increase in blood pressure, redistribution of blood flow, and bradycardia. We tested whether apnea induces an elevation of catecholamine-concentrations in well-trained apneic divers.11 apneic divers performed maximal dry apnea in a horizontal position. Parameters measured during apnea included blood pressure, ECG, and central, in addition to peripheral hemoglobin oxygenation. Peripheral arterial hemoglobin oxygenation was detected by pulse oximetry, whereas peripheral (abdominal) and central (cerebral) tissue oxygenation was measured by Near Infrared Spectroscopy (NIRS). Exhaled O2 and CO2, plasma norepinephrine and epinephrine concentrations were measured before and after apnea.Averaged apnea time was 247±76 s. Systolic blood pressure increased from 135±13 to 185±25 mmHg. End-expiratory CO2 increased from 29±4 mmHg to 49±6 mmHg. Norepinephrine increased from 623±307 to 1 826±984 pg ml-1 and epinephrine from 78±22 to 143±65 pg ml-1 during apnea. Heart rate reduction was inversely correlated with increased norepinephrine (correlation coefficient -0.844, p=0.001). Central (cerebral) O2 desaturation was time-delayed compared to peripheral O2 desaturation as measured by NIRSabdominal and SpO2.Increased norepinephrine caused by apnea may contribute to blood shift from peripheral tissues to the CNS and thus help to preserve cerebral tissue O2 saturation longer than that of peripheral tissue.

A single air dive induces apoptotic gene regulation but no increase in nucleosomes.

BACKGROUND: Oxidative stress caused by elevated partial pressure of oxygen during diving is a major contributor of inflammation and apoptosis. The underlying molecular mechanisms are poorly understood. The aim of the study was to describe apoptotic gene regulation induced by a single air dive. METHODS: 19 healthy volunteers were exposed to a 30-minute dive at 2.8 atmospheres (ATA) absolute in a pressure chamber in ambient air. Blood samples were obtained before, directly after and 24 hours after exposure. Gene expressions of Bcl-2, Bcl-xL and Bax were analyzed in mononuclear cell extracts by real-time polymerase chain reaction (PCR). Circulating nucleosomes were measured in serum before exposure and 24 hours afterward. RESULTS: The pro-apoptotic Bax expression was not significantly increased (p=0.74) directly after the dive but was induced (2.22 ± 0.85-fold) after 24 hours (p ≤ 0.01). Bcl-2 expression was not changed significantly directly after (p = 0.11) but was 1.88 ± 1.08-fold higher after 24 hours (p ≤ 0.01). Bcl-xL expression was not elevated significantly (p = 0.54) but was 2.04 ± 1.02-fold higher after 24 hours (p ≤ 0.01). The level of nucleosomes did not change after 24 hours compared to baseline. CONCLUSION: A single air dive at 2.8 ATA for 30 minutes causes an upregulation of pro- and anti-apoptotic genes but did not elevate circulating nucleosomes. In a single air dive the upregulation of anti-apoptotic Bcl-2 family members may counteract the pro-apoptotic potential of Bax.

Evaluation of near-infrared spectroscopy under apnea-dependent hypoxia in humans.

In this study we investigated the responsiveness of near-infrared spectroscopy (NIRS) recordings measuring regional cerebral tissue oxygenation (rSO2) during hypoxia in apneic divers. The goal was to mimic dynamic hypoxia as present during cardiopulmonary resuscitation, laryngospasm, airway obstruction, or the "cannot ventilate cannot intubate" situation. Ten experienced apneic divers performed maximal breath hold maneuvers under dry conditions. SpO2 was measured by Masimo™ pulse oximetry on the forefinger of the left hand. NIRS was measured by NONIN Medical's EQUANOX™ on the forehead or above the musculus quadriceps femoris. Following apnea median cerebral rSO2 and SpO2 values decreased significantly from 71 to 54 and from 100 to 65%, respectively. As soon as cerebral rSO2 and SpO2 values decreased monotonically the correlation between normalized cerebral rSO2 and SpO2 values was highly significant (Pearson correlation coefficient = 0.893). Prior to correlation analyses, the values were normalized by dividing them by the individual means of stable pre-apneic measurements. Cerebral rSO2 measured re-saturation after termination of apnea significantly earlier (10 s, SD = 3.6 s) compared to SpO2 monitoring (21 s, SD = 4.4 s) [t(9) = 7.703, p < 0.001, r(2) = 0.868]. Our data demonstrate that NIRS monitoring reliably measures dynamic changes in cerebral tissue oxygen saturation, and identifies successful re-saturation faster than SpO2. Measuring cerebral rSO2 may prove beneficial in case of respiratory emergencies and during pulseless situations where SpO2 monitoring is impossible.

Carbon monoxide intoxication with a CO-Hb of 30% while smoking waterpipe: a case report.

Carbon monoxide (CO) poisoning is a significant public health issue and a considerable economic burden in developed countries. While the majority of non-fire-related CO poisonings are attributed to gas heating, there are several other less recognized sources that should be considered in the initial differential diagnosis.The patient in this case was a 21-year-old who experienced a brief episode of loss of consciousness and was subsequently admitted to the Emergency department. Upon evaluation, the patient was diagnosed with CO poisoning, which necessitated hyperbaric oxygen therapy to mitigate the effects of this toxic exposure.Despite exhibiting harmful symptoms initially, the patient stated in a phone interview two and a half years post-incident that they have not experienced any enduring effects such as cardiac arrhythmia or concentration deficits. While their understanding of the risks associated with waterpipe smoking has increased, it has not influenced any major changes in their waterpipe smoking habits.

Pain management with epidural catheter and epidural analgesia after spinal dorsal instrumentation of lumbar spine.

Spinal dorsal instrumentation (SDI) is an established treatment for degenerative spinal diseases. Adequate and immediate postoperative pain control is important for patient recovery and may be compromised by uncertainty about its efficacy and concern about early postoperative surgical complications or adverse events. The aim of the current study was to compare the use of epidural analgesia (EA) with systemic analgesia (SA) as regards pain reduction and early postoperative complications after SDI. Pain management with epidural or systemic analgesia in patients undergoing SDI by posterior approach between January 2019 and July 2020 was evaluated by clinical functional testing, measuring total opioid amounts used, and evaluating numerical rating scale values 24 and 96 hours postoperatively. The following were also monitored: demographic data, number of affected segments, length of hospital stay, inflammatory markers (leukocytes and serum C-reactive protein), early postoperative surgical complication rates, and adverse events. In total 79 patients were included (33 in the EA and 46 in the SA group). The SA group had significantly lower numerical rating scale values at days 1 to 4 after surgery (P ≤ .001) and lower cumulative opioid use than the EA group (P < .001). We found no difference in infection parameters, length of hospital stay or surgery-related complication rates. Our data demonstrate that epidural anesthesia was inferior to an opioid-based SA regime in reducing postoperative pain in patients undergoing spinal surgery. There is no benefit to the use of epidural catheters.

Safety Evaluation of Cervical Dorsal Instrumentation in Geriatric Patients: Experience at a Level 1 Center for Spinal Surgery-A Single Center Cohort Study.

Objective: Dorsal instrumentation of the cervical spine is an established treatment in spine surgery. However, careful planning is required, particularly in elderly patients. This study evaluates early clinical outcomes in geriatric patients undergoing complex spine surgery. Methods: In this retrospective, single center cohort study, we included all geriatric patients (aged ≥65 years) who underwent dorsal instrumentation between January 2013 and December 2020. We analyzed postoperative complications and the 30-day in-hospital mortality rate. Furthermore, the Charlson comorbidity index (CCI) and Clavien-Dindo grading system (CDG) were used to assess the patients' comorbidity burden. Results: In total, 153 patients were identified and included. The mean age of patients was 78 years (SD ± 7). Traumatic injury (53.6%) was the most common reason for surgery. 60.8% of the patients underwent dorsal instrumentation with 3 or more levels. The most common comorbidities were arterial hypertension (64%), diabetes mellitus (22.2%), coronary heart disease and atrial fibrillation (19.6%). The most common adverse event (AE) was pneumonia (4%) and the most common surgery-related complication was wound infection (5.2%). Among patients categorized as high risk for AE (CCI > 5), 14.6% suffered a postoperative AE. In our univariate analysis, we found no risk factors for high rates of complications or mortality. Conclusion: Our data demonstrates that older patients were at no significant risk of postoperative complications. The CCI/CDG scores may identify patients at higher risk for adverse events after dorsal instrumentation, and these assessments should become an essential component of stratification in this older patient population.

Patient Safety Comparison of Frameless and Frame-Based Stereotactic Navigation for Brain Biopsy-A Single Center Cohort Study.

Leksell stereotactic system-based aspiration biopsy is a common procedure in the neurosurgical treatment of deep-seated or multiple brain lesions. This study aimed to evaluate the benefit of frameless biopsy using VarioGuide compared to frame-based biopsy using the Leksell stereotactic system (LSS). We analyzed all brain biopsies using VarioGuide or LSS at our neurooncological Department of Neurosurgery in the University Hospital of Bonn between January 2018 and August 2020. We analyzed demographic data, duration of surgery, size of lesion, localization, and early complications. Uni-variable analyses were carried out on data from both groups. In total, 109 biopsies were compared (40 VarioGuide vs. 69 LSS). Patients with VarioGuide were significant older (74 (62−80) years vs. 67 (57−76) years; p = 0.03) and had a shorter duration of general anesthesia (163 (138−194) min vs. 193 (167−215) min, p < 0.001). We found no significant differences in surgery duration (VarioGuide median 28 min (IQR 20−38); LSS: median 30 min (IQR 25−39); p = 0.1352) or in early complication rates (5% vs. 7%; p = 0.644). A slightly higher false negative biopsy rate was registered in the LSS group (3 vs. 1; p = 0.1347). The size of the lesions also did not differ significantly between the two groups (18.31 ± 26.35 cm3 vs. 12.63 ± 14.62; p = 0.15). Our data showed that biopsies performed using VarioGuide took significantly less time than LSS biopsies and did not differ in complication rates. Both systems offered a high degree of patient safety.

A Validation Study for SHE Score for Acute Subdural Hematoma in the Elderly.

OBJECTIVE: The aim of this study was the verification of the Subdural Hematoma in the Elderly (SHE) score proposed by Alford et al. as a mortality predictor in patients older than 65 years with nontraumatic/minor trauma acute subdural hematoma (aSDH). Additionally, we evaluated further predictors associated with poor outcome. METHODS: Patients were scored according to age (1 point is given if patients were older than 80 years), GCS by admission (1 point for GCS 5-12, 2 points for GCS 3-4), and SDH volume (1 point for volume 50 mL). The sum of points determines the SHE score. Multivariate logistic regression analysis was performed to identify additional independent risk factors associated with 30-day mortality. RESULTS: We evaluated 131 patients with aSDH who were treated at our institution between 2008 and 2020. We observed the same 30-day mortality rates published by Alford et al.: SHE 0: 4.3% vs. 3.2%, p = 1.0; SHE 1: 12.2% vs. 13.1%, p = 1.0; SHE 2: 36.6% vs. 32.7%, p = 0.8; SHE 3: 97.1% vs. 95.7%, p = 1.0 and SHE 4: 100% vs. 100%, p = 1.0. Additionally, 18 patients who developed status epilepticus (SE) had a mortality of 100 percent regardless of the SHE score. The distribution of SE among the groups was: 1 for SHE 1, 6 for SHE 2, 9 for SHE 3, and 2 for SHE 4. The logistic regression showed the surgical evacuation to be the only significant risk factor for developing the seizure. All patients who developed SE underwent surgery (p = 0.0065). Furthermore, SHE 3 and 4 showed no difference regarding the outcome between surgical and conservative treatment. CONCLUSIONS: SHE score is a reliable mortality predictor for minor trauma acute subdural hematoma in elderly patients. In addition, we identified status epilepticus as a strong life-expectancy-limiting factor in patients undergoing surgical evacuation.

The necessity for routine intensive care unit admission following elective craniotomy for epilepsy surgery: a retrospective single-center observational study.

OBJECTIVE: Traditionally, patients who underwent elective craniotomy for epilepsy surgery are monitored postoperatively in an intensive care unit (ICU) overnight in order to sufficiently respond to potential early postoperative complications. In the present study, the authors investigated the frequency of early postoperative events that entailed ICU monitoring in patients who had undergone elective craniotomy for epilepsy surgery. In a second step, they aimed at identifying pre- and intraoperative risk factors for the development of unfavorable events to distinguish those patients with the need for postoperative ICU monitoring at the earliest possible stage. METHODS: The authors performed a retrospective observational cohort study assessing patients with medically intractable epilepsy (n = 266) who had undergone elective craniotomy for epilepsy surgery between 2012 and 2019 at a tertiary care epilepsy center, excluding those patients who had undergone invasive diagnostic approaches and functional hemispherectomy. Postoperative complications were defined as any unfavorable postoperative surgical and/or anesthesiological event that required further ICU therapy within 48 hours following surgery. A multivariate analysis was performed to reveal preoperatively identifiable risk factors for postoperative adverse events requiring an ICU setting. RESULTS: Thirteen (4.9%) of 266 patients developed early postoperative adverse events that required further postoperative ICU care. The most prevalent event was a return to the operating room because of relevant postoperative intracranial hematoma (5 of 266 patients). Multivariate analysis revealed intraoperative blood loss ≥ 325 ml (OR 6.2, p = 0.012) and diabetes mellitus (OR 9.2, p = 0.029) as risk factors for unfavorable postoperative events requiring ICU therapy. CONCLUSIONS: The present study revealed routinely collectable risk factors that would allow the identification of patients with an elevated risk of postsurgical complications requiring a postoperative ICU stay following epilepsy surgery. These findings may offer guidance for a stepdown unit admission policy following epilepsy surgical interventions after an external validation of the results.

Postoperative prolonged mechanical ventilation correlates to poor survival in patients with surgically treated spinal metastasis.

Objective: Patients with spinal metastasis (SM) are at advanced stages of systemic cancer disease. Surgical therapy for SM is a common treatment modality enabling histopathological diagnosis and the prevention of severe neurological deficits. However, surgery for SM in this vulnerable patient cohort may require prolonged postoperative intensive care treatment, which could adversely affect the anticipated benefit of the surgery. We therefore assessed postoperative prolonged mechanical ventilation (PMV) as an indicator for intensive care treatment with regard to potential correlations with early postoperative mortality and overall survival (OS). Methods: Between 2015 and 2019, 198 patients were surgically treated for SM at the author´s neurosurgical department. PMV was defined as postoperative mechanical ventilation of more than 24 hours. A multivariate analysis was performed to identify pre- and perioperative collectable predictors for 30 days mortality. Results: Twenty out of 198 patients (10%) with SM suffered from postoperative PMV. Patients with PMV exhibited a median OS rate of 1 month compared to 12 months for patients without PMV (p < 0.0001). The 30 days mortality was 70% and after one year 100%. The multivariate analysis identified "PMV > 24 hrs" (p < 0.001, OR 0.3, 95% CI 0.02-0.4) as the only significant and independent predictor for 30 days mortality (Nagelkerke's R2 0.38). Conclusions: Our data indicate postoperative PMV to significantly correlate to high early postoperative mortality rates as well as to poor OS in patients with surgically treated SM. These findings might encourage the initiation of further multicenter studies to comprehensively investigate PMV as a so far underestimated negative prognostic factor in the course of surgical treatment for SM.

Going to Extremes of Lung Physiology-Deep Breath-Hold Diving.

Breath-hold diving involves environmental challenges, such as water immersion, hydrostatic pressure, and asphyxia, that put the respiratory system under stress. While training and inherent individual factors may increase tolerance to these challenges, the limits of human respiratory physiology will be reached quickly during deep breath-hold dives. Nonetheless, world records in deep breath-hold diving of more than 214 m of seawater have considerably exceeded predictions from human physiology. Investigations of elite breath-hold divers and their achievements revised our understanding of possible physiological adaptations in humans and revealed techniques such as glossopharyngeal breathing as being essential to achieve extremes in breath-hold diving performance. These techniques allow elite athletes to increase total lung capacity and minimize residual volume, thereby reducing thoracic squeeze. However, the inability of human lungs to collapse early during descent enables respiratory gas exchange to continue at greater depths, forcing nitrogen (N2) out of the alveolar space to dissolve in body tissues. This will increase risk of N2 narcosis and decompression stress. Clinical cases of stroke-like syndromes after single deep breath-hold dives point to possible mechanisms of decompression stress, caused by N2 entering the vasculature upon ascent from these deep dives. Mechanisms of neurological injury and inert gas narcosis during deep breath-hold dives are still incompletely understood. This review addresses possible hypotheses and elucidates factors that may contribute to pathophysiology of deep freediving accidents. Awareness of the unique challenges to pulmonary physiology at depth is paramount to assess medical risks of deep breath-hold diving.

Rapid Ventricular Pacing as a Safe Procedure for Clipping of Complex Ruptured and Unruptured Intracranial Aneurysms.

Surgical treatment of intracranial aneurysm requires advanced technologies to achieve optimal results. Recently, rapid ventricular pacing (RVP) has been described to be an elegant technique that facilitates clip reconstruction of complex unruptured intracranial aneurysm (uIA). However, there is also a growing need for intraoperative tools to ensure safe clip reconstruction of complex ruptured intracranial aneurysm (rIA). We conducted a retrospective analysis of 17 patients who underwent RVP during surgical reconstruction of complex aneurysms. Nine patients had uIA while eight patients underwent surgery for rIA suffering from consecutive subarachnoid hemorrhage (SAH). Hemodynamic data, critical events, laboratory results, and anesthesia-related complications were evaluated. No complications were reported concerning anesthesia induction and induction times were similar between patients exhibiting uIA or rIA (p = 0.08). RVP induced a significant decline of median arterial pressure (MAP) in both groups (p < 0.0001). However, median MAP before and after RVP was not different in both groups (uIA group: p = 0.27; rIA group: p = 0.18). Furthermore, high-sensitive Troponin T (hsTnT) levels were not increased after RVP in any group. One patient in the rIA group exhibited ventricular fibrillation and required cardiopulmonary resuscitation, but has presented with cardiac arrest due to SAH. Otherwise, no arrhythmias or complications occurred. In summary, our data suggest RVP to be feasible in surgery for ruptured intracranial aneurysms.