Effect of Extracerebral Contamination on Near-infrared Spectroscopy as Revealed during Organ Donation: A Prospective Observational Study in Brain-dead Organ Donors.

BACKGROUND: Near-infrared spectroscopy (NIRS) has been utilized widely in anesthesia and intensive care to monitor regional cerebral oxygen saturation (rScO2). A normal oxygenation of extracerebral tissues may overlay and thereby mask cerebral desaturations, a phenomenon known as extracerebral contamination. The authors investigated the effect of a cessation of extracerebral tissue perfusion on rScO2 in patients with anoxic brains. METHODS: In a single-center, prospective, observational study, brain-dead adults undergoing organ donation were investigated. rScO2 was measured bifrontally using the INVOS 5100C/7100 as well as the ForeSight Elite system. To achieve an efficient conservation of organs and to prevent a redistribution of the perfusion fluid to other tissues, the aorta was clamped before organ perfusion. rScO2 was monitored until at least 40 min after aortic clamping. The primary outcome was the amount of extracerebral contamination as quantified by the absolute decrease in rScO2 after aortic clamping. Secondary outcomes were the absolute rScO2 values obtained before and after clamping. RESULTS: Twelve organ donors were included. Aortic clamping resulted in a significantly (P < 0.001) greater absolute decrease in rScO2 when comparing the INVOS (43.0 ± 9.5%) to the ForeSight (27.8 ± 7.1%) monitor. Before aortic clamping, near-normal rScO2 values were obtained by the INVOS (63.8 ± 6.2%) and the ForeSight monitor (67.7 ± 6.5%). The rScO2 significantly (P < 0.001) dropped to 20.8 ± 7.8% (INVOS) and 39.9 ± 8.1% (ForeSight) 30 min after clamping, i.e., a condition of a desaturation of both extracerebral and cerebral tissues. CONCLUSIONS: The abrupt end of extracerebral contamination, caused by aortic clamping, affected both NIRS monitors to a considerable extent. Both the INVOS and the ForeSight monitor were unable to detect severe cerebral hypoxia or anoxia under conditions of normal extracerebral oxygenation. While both NIRS monitors may guide measures to optimize arterial oxygen supply to the head, they should not be used with the intention to detect isolated cerebral desaturations.

Preoperative cerebral oxygenation in high-risk noncardiac surgical patients: an observational study on postoperative mortality and complications.

Near Infrared Spectroscopy (NIRS) has become widely accepted to evaluate regional cerebral oxygen saturation (rScO2), potentially acting as a surrogate parameter of reduced cerebral oxygen delivery or increased consumption. Low preoperative rScO2 is associated with increased postoperative complications after cardiac surgery. However, its universal potential in pre-anesthesia risk assessment remains unclear. Therefore, we investigated whether low preoperative rScO2 is indicative of postoperative complications and associated with poor outcomes in noncardiac surgical patients. We prospectively enrolled 130 patients undergoing high-risk noncardiac surgery. During pre-anesthesia evaluation, baseline rScO2 was recorded with and without oxygen supplementation. The primary endpoint was 30-day mortality, while secondary endpoints were postoperative myocardial injury, respiratory complications, and renal failure. We further evaluated the impact of body position and preoperative hemoglobin (Hb) concentration on rScO2. Of the initially enrolled 130 patients, 126 remained for final analysis. Six (4.76%) patients died within 30 postoperative days. 95 (75.4%) patients were admitted to the ICU. 32 (25.4%) patients suffered from major postoperative complications. There was no significant association between rScO2 and 30-day mortality or secondary endpoints. Oxygen supplementation induced a significant increase of rScO2. Furthermore, Hb concentration correlated with rScO2 values and body position affected rScO2. No significant association between rScO2 values and NYHA, LVEF, or MET classes were observed. Preoperative rScO2 is not associated with postoperative complications in patients undergoing high-risk noncardiac surgery. We speculate that the discriminatory power of NIRS is insufficient due to individual variability of rScO2 values and confounding factors.

Pupillary Pain Index Predicts Postoperative Pain but Not the Effect of Peripheral Regional Anaesthesia in Patients Undergoing Total Hip or Total Knee Arthroplasty: An Observational Study.

Background and Objectives: The pupillary pain index (PPI) allows the evaluation of intraoperative nociception by measuring pupillary reaction after a localized electrical stimulus. It was the objective of this observational cohort study to investigate the pupillary pain index (PPI) as a method to evaluate the fascia iliaca block (FIB) or adductor canal block (ACB) sensory areas during general anaesthesia in orthopaedic patients with lower-extremity joint replacement surgery. Materials and Methods: Orthopaedic patients undergoing hip or knee arthroplasty were included. After anaesthesia induction, patients received an ultrasound-guided single-shot FIB or ACB with 30 mL and 20 mL of 0.375% ropivacaine, respectively. Anaesthesia was maintained with isoflurane or propofol/remifentanil. The first PPI measurements were performed after anaesthesia induction and before block insertion, the second at the end of surgery. Pupillometry scores were evaluated in the area of the femoral or saphenous nerve (target) and C3 dermatome (control). Primary outcomes were differences between PPIs before and after peripheral block insertion as well as the relationship between PPIs and postoperative pain scores; secondary outcomes were the relationship between PPIs and opioid requirements after surgery. Results: PPI decreased significantly from the first to the second measurement (4.17 ± 2.7 vs. 1.6 ± 1.2, p < 0.001 for target; 4.46 ± 2.7 vs. 2.17 ± 2.1, p < 0.001 for control). Control and target measurements did not show significant differences. A linear regression analysis showed that early postoperative pain scores could be predicted with intraoperative piritramide with improved prediction after adding PPI scores, PCA opioids and surgery type. Forty-eight-hour pain scores at rest and in movement were correlated with intraoperative piritramide and control PPI after the PNB in movement and with second-postoperative-day opioids and target PPI scores before block insertion, respectively. Conclusions: While the effect of an FIB and ACB could not be shown with PPI postoperative pain scores due to a large effect of opioids, perioperative PPI was shown to be associated with postoperative pain. These results suggest that preoperative PPI may be used to predict postoperative pain.

Influence of Intraoperative Nociception during Hip or Knee Arthroplasty with Supplementary Regional Anaesthesia on Postoperative Pain and Opioid Consumption.

Background and Objectives: Early postoperative mobilization is central for postoperative outcomes after lower extremity joint replacement surgery. By providing adequate pain control, regional anaesthesia plays an important role for postoperative mobilization. It was the objective of this study to investigate the use of the nociception level index (NOL) to determine the effect of regional anaesthesia in hip or knee arthroplasty patients undergoing general anaesthesia with additional peripheral nerve block. Materials and Methods: Patients received general anaesthesia, and continuous NOL monitoring was established before anaesthesia induction. Depending on the type of surgery, regional anaesthesia was performed with a Fascia Iliaca Block or an Adductor Canal Block. Results: For the final analysis, 35 patients remained, 18 with hip and 17 with knee arthroplasty. We found no significant difference in postoperative pain between hip or knee arthroplasty groups. NOL increase at the time of skin incision was the only parameter associated with postoperative pain measured using a numerical rating scale (NRS > 3) after 24 h in movement (-12.3 vs. +119%, p = 0.005). There was no association with intraoperative NOL values and postoperative opioid consumption, nor was there an association between secondary parameters (bispectral index, heart rate) and postoperative pain levels. Conclusions: Intraoperative NOL changes may indicate regional anaesthesia effectiveness and could be associated with postoperative pain levels. This remains to be confirmed in a larger study.

Improving quality of life in pancreatic cancer patients following high-intensity focused ultrasound (HIFU) in two European centers.

OBJECTIVES: Pancreatic cancer patients often have a high symptom burden, significantly impairing patients' quality of life (QOL). Nevertheless, there are hardly any reports on the impact of high-intensity focused ultrasound (HIFU) on the QOL of treated patients. For the first time, this study evaluated the effect of HIFU on QOL and compared these results in two European centers. METHODS: Eighty patients with advanced pancreatic cancer underwent HIFU (50 in Germany, 30 in Bulgaria). Clinical assessment included evaluation of QOL and symptoms using the EORTC QLQ-C30 questionnaire at baseline and 1, 3, and 6 months after HIFU. Pain intensity was additionally evaluated with the numerical rating score (NRS). RESULTS: Compared to baseline, global health significantly improved 3 and 6 months after HIFU treatment (p = 0.02). Functional subscales including physical, emotional, and social functioning were considerably improved at 6 months (p = 0.02, p = 0.01, and p = 0.01, respectively) as were leading symptom pain (p = 0.04 at 6 months), fatigue (p = 0.03 at 3 and p = 0.01 at 6 months), and appetite loss (p = 0.01 at 6 months). Moreover, pain intensity measured by NRS revealed effective and strong pain relief at all time points (p < 0.001). Reported effects were independent of tumor stage, metastatic status, and country of treatment. CONCLUSIONS: This study showed that HIFU represents an effective treatment option of advanced pancreatic cancer improving QOL by increasing global health and mitigation of physical complaints with a low rate of side effects, independent of the examiner. Therefore, HIFU is a worthwhile additional treatment besides systemic palliative chemotherapy or best supportive care in management of this aggressive disease. KEY POINTS: • In a prospective two-center study, it was shown that HIFU represents an effective treatment option of advanced pancreatic cancer improving QOL. • HIFU in pancreatic cancer patients is associated with a low rate of side effects, independent of the performer. • HIFU is a worthwhile additional treatment besides systemic palliative chemotherapy or best supportive care in management of this aggressive disease.

Controlled arterial hypotension during resection of cerebral arteriovenous malformations.

BACKGROUND: Resection of cerebral arteriovenous malformations (AVM) is technically demanding because of size, eloquent location or diffuse nidus. Controlled arterial hypotension (CAH) could facilitate haemostasis. We performed a study to characterize the duration and degree of CAH and to investigate its association with blood loss and outcome. METHODS: We retrospectively analysed intraoperative arterial blood pressure of 56 patients that underwent AVM-resection performed by the same neurosurgeon between 2003 and 2012. Degree of CAH, AVM size, grading and neurological outcome were studied. Patients were divided into two groups, depending on whether CAH was performed (hypotension group) or not (control group). RESULTS: The hypotension group consisted of 28 patients, which presented with riskier to treat AVMs and a higher Spetzler-Martin grading. CAH was achieved by application of urapidil, increasing anaesthetic depth or a combination thereof. Systolic and mean arterial blood pressure were lowered to 82 ± 7 and 57 ± 7 mmHg, respectively, for a median duration of 58 min [25% percentile: 26 min.; 75% percentile: 107 min]. In the hypotension group, duration of surgery (4.4 ± 1.3 h) was significantly (p <  0.001) longer, and median blood loss (500 ml) was significantly (p = 0.002) higher than in the control group (3.3 ± 0.9 h and 200 ml, respectively). No case fatalities occurred. CAH was associated with a higher amount of postoperative neurological deficits. CONCLUSIONS: Whether CAH caused neurological deficits or prevented worse outcomes could be clarified by a prospective randomised study, which is regarded as ethically problematic in the context of bleeding. CAH should only be used after strict indication and should be applied as mild and short as possible.

Single tests of implantable cardioverter defibrillators can be performed in selected patients at a low risk of neuronal damage.

BACKGROUND: Defibrillator testing (DFT) is still used in selected patients to ensure adequate therapy. To do so, ventricular fibrillation is induced and terminated by the implanted cardioverter defibrillator (ICD). Studies have shown increases in neuronal damage markers without a measurable clinical effect in patients after defibrillator threshold testing with multiple shocks. OBJECTIVE: The aim of this study was to measure clinical outcomes, neuronal damage parameters (NSE and S100), and intraoperative cerebral perfusion (Doppler, near infra-red spectroscopy [NIRS]) in patients undergoing single DFT after transvenous ICD implantation and comparing them to untested patients. METHOD: We included 23 patients. Nine underwent surgery with a single DFT, 14 were not tested. Cognitive impairment was tested using the Mini-Mental-Status Test (MMST) and the DEMTECt 24 h prior and postsurgery. We also measured S100 and Neuron-Specific Enolase (NSE) at these timepoints. During surgery we measured medial cerebral artery velocity and cerebral tissue oxygen saturation (rSO2 ). RESULTS: We found no significant differences between the patient groups except for a significant increase in mean arterial blood pressure and an increase in rSO2 after testing. One patient with cerebral vasculopathy had a significant increase in his NSE values without showing clinical symptoms. This patient also had low rSO2 measurements and a decrease in medial cerebral artery velocity after DFT, other than the other patients. CONCLUSION: Single DFT did not lead to signs of neuronal damage or cognitive impairment except in one case with pre-existing cerebral vasculopathy. Therefore, our results support the use of DFT in carefully selected patients.

US-guided high-intensity focused ultrasound (HIFU) of abdominal tumors: outcome, early ablation-related laboratory changes and inflammatory reaction. A single-center experience from Germany.

INTRODUCTION: High-intensity focused ultrasound (HIFU) is an innovative noninvasive procedure for local ablation of different benign and malignant tumors. Preliminary data of animal studies suggest an ablation-associated immune response after HIFU that is induced by cell necrosis and release of intracellular components. The aim of this study is to evaluate if a HIFU-induced early sterile inflammatory reaction is initiated after ablation of uterine fibroids (UF) and pancreatic carcinoma (PaC) which might contribute to the therapeutic effect. MATERIAL AND METHODS: A hundred patients with PaC and 30 patients with UF underwent US-guided HIFU treatment. Serum markers of inflammation (leukocytes, CRP, IL-6) and LDH in both collectives as well as tumor markers CA 19-9, CEA and CYFRA in PaC patients were determined in sub-cohorts before and directly after HIFU (0, 2, 5 and 20 h post-ablation) as well as at 3, 6, 9 and 12 months follow-up. Peri-/post interventional imaging included contrast-enhanced MRI of both cohorts and an additional CT scan of PaC patients. RESULTS: An early post-ablation inflammatory response was observed in both groups with a significant increase of leukocytes, CRP and LDH within the first 20 h after HIFU. Interestingly, IL-6 was increased at 20 h after HIFU in PaC patients. A significant reduction of tumor volumes was observed during one year follow-up (p < .001) for both tumor entities demonstrating effective treatment outcome. CONCLUSION: Tumor ablation with HIFU induces an early sterile inflammation that might serve as a precondition for long-term tumor immunity and a sustainable therapeutic effect.

Efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for uterine fibroids: an observational single-center study.

INTRODUCTION: To evaluate treatment response of uterine fibroids after ultrasound guided high-intensity focused ultrasound (USgHIFU) with a special focus on fibroid size and characterization based on Funaki classification scheme, as well as clinical response to treatment of leading fibroid-associated symptoms. MATERIALS AND METHODS: Uterine fibroids treated by USgHIFU were assigned to Funaki type 1-3 based on T2-w-MRI. Differences in size, non-perfused volume ratio (NPVR) and volume reduction over time were determined using T1-/T2-w MRI sequences and contrast-enhanced sonography. Treatment effects on three leading fibroid-associated symptoms were also evaluated. Measurements were compared by mixed model, Bland-Altman's plot and Spearman's correlation. RESULTS: In this prospective single-center study, 35 patients with 44 symptomatic uterine fibroids were treated by USgHIFU (n = 22, n = 12 and n = 10 assigned to Funaki type 1, 2 and 3, respectively). NPVRs of Funaki type 1 and 2 fibroids were significantly higher compared to type 3 (p = .0023). A significant fibroid shrinkage was observed independent of Funaki type compared to baseline: 38.8 ± 26.9%, 46.7 ± 30.3% and 54.5 ± 29.3% at 3, 6 and 12 months, respectively (each p < .05). Moreover, patients experienced a significant improvement of fibroid-associated hypermenorrhea (3.9 ± 1.3 vs. 2.3 ± 1.3), pressure in the pelvic area (3.5 ± 1.3 vs. 2.1 ± 0.9) and frequent urination (2.8 ± 1.5 vs. 1.9 ± 0.8) one year post-procedure (each p < .05), regardless of fibroid Funaki type. CONCLUSION: Following USgHIFU, a significant shrinkage of uterine fibroids and improvement of leading fibroid-associated symptoms were demonstrated regardless of the Funaki type.

Extended neuromonitoring in aortic arch surgery : A case series.

BACKGROUND: Aortic arch repair for aortic dissection is still associated with a high mortality rate. Providing adequate means of neuromonitoring to guide cerebral hemodynamics is advantageous, especially during selective anterior cerebral perfusion (SACP). OBJECTIVE: We aimed to investigate an easy multimodal neuromonitoring set-up consisting of processed electroencephalography (EEG), near infrared spectroscopy (NIRS), and transcranial doppler sonography (TCD). MATERIAL AND METHODS: We collected intraoperative data from six patients undergoing surgery for aortic dissection. In addition to standard hemodynamic monitoring, patients underwent continuous bilateral NIRS, processed EEG with bispectral index (BIS), and intermittent transcranial doppler sonography of the medial cerebral artery (MCA) with a standard B­mode ultrasound device. Doppler measurements were taken bilaterally before cardiopulmonary bypass (CPB), during CPB, and during SACP at regular intervals. RESULTS: Of the patients four survived without neurological deficits while two suffered fatal outcomes. Of the survivors two suffered from transient postoperative delirium. Multimodal monitoring led to a change in CPB flow or cannula repositioning in three patients. Left-sided mean flow velocities of the MCA decreased during SACP, as did BIS values. CONCLUSION: Monitoring consisting of BIS, NIRS, and TCD may have an impact on hemodynamic management in aortic arch operations.

[Evaluation of the Effectiveness of a Standard Operating Procedure (SOP) for the Perioperative Management of Colorectal Surgery]. / Evaluation der Effektivität einer Standard Operating Procedure (SOP) zur perioperativen Therapie bei kolorektalen Operationen.

INTRODUCTION: In recent years, perioperative care of patients after colorectal surgery has been increasingly standardised according to the fast-track concept and is accepted as a structured method of care to reduce perioperative complications. Indeed, initial studies have indicated that there is a long-term favourable effect on the oncological outcome, if the adherence to the individual measures is at least 70%. Even though there is unambiguous evidence for the efficacy of the modern perioperative treatment concept, it is often difficult to comply with the protocol during normal clinical work, particularly in Germany. The objective of this study was to record the rate of compliance before and after the introduction of the SOP and to evaluate its efficacy. METHODS: We performed a retrospective analysis of the patient data after all elective colorectal surgery in the Bonn University Hospital from 2017 to 2020. 153 patients were operated on before the implementation of the SOP in January 2019 (group I); the remaining 153 patients were operated on after the implementation of the SOP and received appropriate care (group II). Compliance to the protocol was analysed for both the individual key interventions and the overall concept. RESULTS: There was significant improvement in the compliance for both the individual measures (prehabilitation group I: 5.9%, group II: 42.5%, p < 0.001; preparation of the intestine I: 16.5%, II: 73.9%, p < 0.001; intraoperative volume management I: 14,00 ml/kg BW/h, II: 9.12 ml/kg BW/h, p < 0.001, BW: body weight; minimally invasive surgical technique I: 53.6%, II: 73.9%, p < 0.001; etc.) and for the overall perioperative treatment concept (I: 39%, II: 54%, p = 0.02). However, we fell far short of compliance of at least 70%. Nevertheless, patient autonomy was achieved earlier after introduction of the SOP (I: day 15, II: day 9, p < 0.001) and the postoperative hospital stay was shortened (I: 14 [6 - 99] days, II 11 [4 - 64] days; p = 0.007). CONCLUSION: Although the implementation of the SOP led to significant improvements, further optimisation is required to attain the recommended protocol compliance of 70%. Measures within the hospital could include foundation of an interdisciplinary fast-track team and a specialised nurse as the connecting link between the patients, nursing and physicians. On the other hand, implementation throughout Germany can only be achieved by more influential actions. One possible support would be the S3 guideline on perioperative management of gastrointestinal tumours, which is under development. This could, for example, be used to support argumentation with funding providers.

Multidisciplinary management and outcome in pancreatic cancer patients treated with high-intensity focused ultrasound.

Introduction: High-intensity focused ultrasound (HIFU) for pancreatic cancer is a growing therapeutic field which has been proven to reduce cancer pain and provide a local tumor control additionally to standard palliative care. However, less is known about the multidisciplinary and especially anesthesiological management of HIFU treatment although an interdisciplinary approach is crucial for treatment success.Material and methods: Anesthesiological and radiological records of 71 HIFU-treated pancreatic cancer patients were analyzed with regard to the following items: intervention time, sonication time, total energy, anesthesia time, peri-interventional medication, body temperature maximum and minimum, pain scores before and 1 day, 6 weeks and 3 months after intervention, peri-interventional complications. Effects on pain scores were estimated with a mixed panel data model. Bivariate associations between interventional variables were examined with the Spearman's correlation.Results: HIFU treatment was performed without major adverse events. Peri-procedural hyperthermia >37.5 °C occurred in 2 patients, hypothermia <35 °C in 8 cases. Interventional variables did not correlate significantly with pain scores, opioid dose, nor body temperature. 85.5% of patients experienced significant early pain relief within the first week after intervention. Post-interventional pain relief is associated with morphine equivalent opioid dose (p = 0.025) and treatment time (p = 0.040).Conclusion: While HIFU can be considered safe and effective treatment option, procedure-associated pain and temperature management represent challenges for the interdisciplinary HIFU intervention team. Especially short-term pain relief depends on the combined effort of the radiologist and anesthesiologist.

Pulmonary function decline in immediate postoperative period is not necessarily related to residual neuromuscular block: An observational study.

BACKGROUND: Previous studies have reported an association between the use of neuromuscular blocking (NMB) agents and postoperative pulmonary complications. Postoperative pulmonary function is a key indicator for postoperative pulmonary complications. Several sites can be used to assess depth and recovery from NMB. OBJECTIVES: To investigate postoperative pulmonary function change in relation to train-of-four measurements at the adductor pollicis and corrugator supercilii muscles, and anaesthesia-related variables in orthopaedic patients undergoing hip or knee arthroplasty. DESIGN: Observational study. SETTING: University hospital. PATIENTS: Orthopaedic patients undergoing hip or knee arthroplasty. MAIN OUTCOME MEASURES: Postoperative pulmonary function tests in the postanaesthesia care unit. METHODS: Patients scheduled for elective hip or knee arthroplasty received simultaneous corrugator supercilii and adductor pollicis measurements during anaesthesia conducted according to clinical standards. Forced expiratory volume in 1 s and forced vital capacity (FVC) were measured at the time of inclusion and postoperatively on the postanaesthesia care unit. Linear regression analysis was performed for association between risk factors and pulmonary function change. RESULTS: A total of 35 patients were included. After exclusions, 20 patients remained for final analysis. Corrugator supercilii showed earlier NMB recovery than adductor pollicis. FVC decreased significantly after surgery from 2.9 ±â€Š1.0 to 2.3 ±â€Š1.0 (P < 0.01) and forced expiratory volume in 1 s decreased from 2.3 ±â€Š0.9 to 1.6 ±â€Š0.8 l (P < 0.01). Patient age was the only factor significantly related to FVC decrease after surgery (P = 0.019) with a cut-off value of 65 years. CONCLUSION: Both corrugator supercilii and adductor pollicis failed to indicate recovery of pulmonary function after NMB. Age seems to be a risk factor for postoperative decline in pulmonary function. TRIAL REGISTRATION: German Clinical Trials registry, DRKS-ID: DRKS00014305.

Suppressive oligodeoxynucleotides containing TTAGGG motifs inhibit cGAS activation in human monocytes.

Type I interferon (IFN) is a critical mediator of autoimmune diseases such as systemic lupus erythematosus (SLE) and Aicardi-Goutières Syndrome (AGS). The recently discovered cyclic-GMP-AMP (cGAMP) synthase (cGAS) induces the production of type I IFN in response to cytosolic DNA and is potentially linked to SLE and AGS. Suppressive oligodeoxynucleotides (ODN) containing repetitive TTAGGG motifs present in mammalian telomeres have proven useful in the treatment of autoimmune diseases including SLE. In this study, we demonstrate that the suppressive ODN A151 effectively inhibits activation of cGAS in response to cytosolic DNA, thereby inhibiting type I IFN production by human monocytes. In addition, A151 abrogated cGAS activation in response to endogenous accumulation of DNA using TREX1-deficient monocytes. We demonstrate that A151 prevents cGAS activation in a manner that is competitive with DNA. This suppressive activity of A151 was dependent on both telomeric sequence and phosphorothioate backbone. To our knowledge this report presents the first cGAS inhibitor capable of blocking self-DNA. Collectively, these findings might lead to the development of new therapeutics against IFN-driven pathologies due to cGAS activation.

Relative cerebral hyperperfusion during cardiopulmonary bypass is associated with risk for postoperative delirium: a cross-sectional cohort study.

BACKGROUND: Our objective was to evaluate if changes in on-pump cerebral blood flow, relative to the pre-bypass baseline, are associated with the risk for postoperative delirium (POD) following cardiac surgery. METHODS: In 47 consecutive adult patients, right middle cerebral artery blood flow velocity (MCAV) was assessed using transcranial Doppler sonography. Individual values, measured during cardiopulmonary bypass (CPB), were normalized to the pre-bypass baseline value and termed MCAVrel. An MCAVrel > 100% was defined as cerebral hyperperfusion. Prevalence of POD was assessed using the Confusion Assessment Method for the Intensive Care Unit. RESULTS: Overall prevalence of POD was 27%. In the subgroup without POD, 32% of patients had experienced relative cerebral hyperperfusion during CPB, compared to 67% in the subgroup with POD (p < 0.05). The mean averaged MCAVrel was 90 (±21) % in the no-POD group vs. 112 (±32) % in the POD group (p < 0.05), and patients developing delirium experienced cerebral hyperperfusion during CPB for about 39 (±35) min, compared to 6 (±11) min in the group without POD (p < 0.001). In a subcohort with pre-bypass baseline MCAV (MCAVbas) below the median MCAVbas of the whole cohort, prevalence of POD was 17% when MCAVrel during CPB was kept below 100%, but increased to 53% when these patients actually experienced relative cerebral hyperperfusion. CONCLUSIONS: Our results suggest a critical role for cerebral hyperperfusion in the pathogenesis of POD following on-pump open-heart surgery, recommending a more individualized hemodynamic management, especially in the population at risk.

Cerebral Function and Perfusion during Cardiopulmonary Bypass: A Plea for a Multimodal Monitoring Approach.

BACKGROUND: Postoperative neurological injury still represents a major cause of morbidity after cardiac surgery. Our objective was to compare the limits as well as advantages of routine monitoring tools for the detection of cerebral function and perfusion deficits during cardiopulmonary bypass in a daily clinical setting. METHODS: Adult patients undergoing elective cardiac surgery with use of cardiopulmonary bypass were included. Patients received monitoring comprising Bispectral Index (BIS), Near Infrared Spectroscopy (NIRS) and assessment of middle cerebral artery flow velocity (MCAV) using transcranial Doppler (TCD) sonography. Measurements were taken after anesthesia induction (at baseline) and every 10 minutes during aortic cross-clamping. Relative deviation from baseline values was calculated. Values were compared with predefined, generally accepted threshold values identifying patients at risk for cerebral functional and perfusion deficits. RESULTS: 30 consecutive patients were included into data analysis. Compared to NIRS as well as BIS monitoring, there was a wide interindividual variability in relative MCAV values for the whole cohort (median 0.9, range 0.39-2.19). Out of 229 measurements in total, 82 BIS but only 30 NIRS and 12 TCD values were lying outside predefined limits. TCD monitoring identified two patients with disturbed cerebral autoregulation, while NIRS remained unremarkable. The latter was significantly associated with systemic hemoglobin levels. Finally, patients with relative MCAV values >1.0 had a higher risk of developing postoperative delirium. CONCLUSION: Our findings reveal inherent technical limitations of each individual monitoring component, such as high interindividual variability (TCD), low spatial resolution (NIRS), or interaction with anesthetics (BIS). We therefore argue for a multimodal neuromonitoring that combines several qualities. Such approach would help reducing these limitations while individual components complement each other, thus providing more patient safety during cardiac surgery. Furthermore, such an approach would be easily applicable in a routine clinical setting.

The Use of Internal Jugular Vein Ultrasonography to Anticipate Low or High Central Venous Pressure During Mechanical Ventilation.

BACKGROUND: Critically low or high central venous pressure (CVP) values, together with systemic hypotension, can indicate hypovolemia or acute heart failure. However, measuring CVP requires the insertion of a central venous catheter, a time-consuming procedure that can be associated with severe complications. OBJECTIVE: We sought to evaluate the use of ultrasonography of the internal jugular vein (IJV) to estimate low or high CVP values in patients who were on ventilation. METHODS: Ultrasonography of IJV dimensions and the collection of hemodynamic data was performed in 47 patients, and the ratio between IJV diameter in the 30° and 0° position was calculated (ratio(30/0)). The predictive value of ratio(30/0) for estimating low and high CVP levels was analyzed using receiver operating characteristic curves. RESULTS: The median IJV diameter ratio(30/0) was 0.49. CVP ranged from 1 to 13 mm Hg (median 7 mm Hg). Seventeen patients had a CVP ≤ 5 mm Hg or lower (defined as "low"), and in 11 patients, values of ≥ 10 mm Hg were measured (defined as "high"). The corresponding IJV diameter ratios increased significantly from 0.34 (in the low CVP group) to 0.9 (in the high CVP group). Receiver operating characteristic analysis revealed a good predictive value of the ratio(30/0) for the prediction of low or high CVP values, respectively. A ratio(30/0) of < 0.45 optimally indicated a low CVP, while > 0.65 was the cutoff value to detect a CVP ≥ 10 mm Hg. CONCLUSION: The estimation of low or high CVP values by IJV ultrasonography in different patient positions can be a helpful instrument for the rapid hemodynamic assessment of the critically ill patient.

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.

Safety, feasibility and complications during resective pediatric epilepsy surgery: a retrospective analysis.

BACKGROUND: Resective epilepsy surgery is an established and effective method to reduce seizure burden in drug-resistant epilepsy. It was the objective of this study to assess intraoperative blood loss, transfusion requirements and the degree of hypothermia of pediatric epilepsy surgery in our center. METHODS: Patients were identified by our epilepsy surgery database, and data were collected via retrospective chart review over the past 25 years. Patients up to the age of 6 years were included, and patients with insufficient data were excluded. RESULTS: Forty-five patients with an age of 3.2 ± 1.6 (mean ± SD) years and a body weight of 17 [14; 21.5] kg (median [25%, 75% percentile]) were analysed. Duration of surgery was 3 h 49 min ± 53 min, which was accompanied by an intraoperative blood loss of 150 [90; 300] ml. This corresponded to 11.7 [5.2; 21.4] % of estimated total blood volume, ranging from 0 to 75%. A minimal haemoglobin count of 8.8 ± 1.4 g/dl was measured, which was substituted with erythrocyte concentrate (100 [0; 250] ml) in 23 patients. Body core temperature dropped from 36.0 ± 0.7°C at baseline to a minimum of 35.7 ± 0.7°C, and increased significantly (p < 0.001) thereafter to 37.1 ± 0.7°C until the end of surgery. A significant (p = 0.0003) correlation between duration of surgery and blood loss (Pearson r = 0.52) was observed. However, age, minimal body temperature or number of antiepileptic drugs seemed to have no impact on blood loss. CONCLUSION: Resective epilepsy surgery is a safe procedure even in the pediatric population, however it is associated with significant blood loss especially during long surgical procedures.