In JoVE (1)

Other Publications (13)

Articles by Richard K. Ellerkmann in JoVE

 JoVE Medicine

A Model to Simulate Clinically Relevant Hypoxia in Humans

1Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Bonn, 2Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, 3Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, 4Institute of Physiology 2, University of Bonn


JoVE 54933

Other articles by Richard K. Ellerkmann on PubMed

The Correlation of the Bispectral Index with Propofol Effect Site Concentrations is Not Altered by Epochs Indicated As Artefact-loaded by Narcotrend

Journal of Clinical Monitoring and Computing. Aug, 2004  |  Pubmed ID: 15779840

Artefact detection is an essential feature of automatic EEG monitoring systems used in anaesthesia. Clinical experience indicates that Narcotrend monitoring (MonitorTechnik, Bad Bramstedt, Germany, version 4.0) excludes more EEG epochs because of artefacts than bispectral index monitoring (BIS, Aspect Medical Systems, Newton, MA, version XP). Whether this increased exclusion of epochs is justified has not been investigated yet.

Comparison Between Bispectral Index and Patient State Index As Measures of the Electroencephalographic Effects of Sevoflurane

Anesthesiology. Nov, 2008  |  Pubmed ID: 18946290

The Bispectral Index (BIS) and the Patient State Index (PSI) quantify depth of anesthesia by analyzing the electroencephalogram. The authors examined the response of BIS and PSI to sevoflurane anesthesia.

Maximizing Prediction Probability PK As an Alternative Semiparametric Approach to Estimate the Plasma Effect-site Equilibration Rate Constant Ke0

Anesthesia and Analgesia. Nov, 2009  |  Pubmed ID: 19713250

The k(e)(0) value is the first order rate constant determining the equilibration of drugs between plasma or end-tidal concentration and effect-site (e.g., brain) concentration. Parametric and semiparametric approaches have been used for estimating individual k(e)(0) values and describing the drug-response curve. In this study, we introduce a new semiparametric approach calculating k(e)(0) values for isoflurane, sevoflurane, and desflurane by maximizing the prediction probability P(K).

Management of Chronic Orofacial Pain: a Survey of General Dentists in German University Hospitals

Pain Medicine (Malden, Mass.). Mar, 2010  |  Pubmed ID: 20447309

This survey assessed procedures performed by general dentists in German university hospitals treating patients with chronic orofacial pain (COP).

Brain Monitoring Revisited: What is It All About?

Best Practice & Research. Clinical Anaesthesiology. Jun, 2013  |  Pubmed ID: 24012234

To easily measure the depth of anaesthesia during routine surgical procedures has always been a goal in anaesthesiology. For decades, scientists have been developing indices to describe and evaluate the depth of anaesthesia. Historically, mean alveolar gas concentration (MAC) values for volatile anaesthetics have been used to target a predefined level of anaesthesia. MAC values were however not established to differentiate between the hypnotic and analgesic components of anaesthesia. Indices were therefore developed that measure the effect of hypnotics predominantly on the brain (in contrast to an effect on the spinal cord) with the vision to be able to measure the transition from consciousness to unconsciousness. Although monitors measuring the depth of anaesthesia are still not capable of measuring the transition from consciousness to unconsciousness, brain monitoring has proved to help clinicians control the depth of anaesthesia. Clinical trials have shown that the use of brain-monitoring devices can lead to a reduction of intraoperative drug consumption, reduced incidence of postoperative nausea and vomiting, facilitate recovery from anaesthesia compared to routine care and can also lead to a reduction of intraoperative awareness. However a study demonstrating both a reduced intraoperative drug consumption and at the same time a reduction of intraoperative awareness due to the use of brain-monitoring devices has not been published yet.

Evaluation of Near-infrared Spectroscopy Under Apnea-dependent Hypoxia in Humans

Journal of Clinical Monitoring and Computing. Dec, 2015  |  Pubmed ID: 25649718

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.

Comparison of Propofol Pharmacokinetic and Pharmacodynamic Models for Awake Craniotomy: A Prospective Observational Study

European Journal of Anaesthesiology. Aug, 2015  |  Pubmed ID: 25774459

Anaesthesia for awake craniotomy aims for an unconscious patient at the beginning and end of surgery but a rapidly awakening and responsive patient during the awake period. Therefore, an accurate pharmacokinetic/pharmacodynamic (PK/PD) model for propofol is required to tailor depth of anaesthesia.

Intraoperative Burst Suppression is Associated with Postoperative Delirium Following Cardiac Surgery: a Prospective, Observational Study

BMC Anesthesiology. Apr, 2015  |  Pubmed ID: 25928189

Postoperative delirium (POD) occurs frequently after cardiac surgery and is associated with increased morbidity and mortality. We analysed whether perioperative bilateral BIS monitoring may detect abnormalities before the onset of POD in cardiac surgery patients.

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

The Journal of Emergency Medicine. Apr, 2016  |  Pubmed ID: 26806319

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.

Human Plasmacytoid Dentritic Cells Elicit a Type I Interferon Response by Sensing DNA Via the CGAS-STING Signaling Pathway

European Journal of Immunology. Jul, 2016  |  Pubmed ID: 27125983

Plasmacytoid dendritic cells (pDCs) are a major source of type I interferon (IFN) and are important for host defense by sensing microbial DNA via TLR9. pDCs also play a critical role in the pathogenesis of IFN-driven autoimmune diseases. Yet, this autoimmune reaction is caused by the recognition of self-DNA and has been linked to TLR9-independent pathways. Increasing evidence suggests that the cytosolic DNA receptor cyclic GMP-AMP (cGAMP) synthase (cGAS) is a critical component in the detection of pathogens and contributes to autoimmune diseases. It has been shown that binding of DNA to cGAS results in the synthesis of cGAMP and the subsequent activation of the stimulator of interferon genes (STING) adaptor to induce IFNs. Our results show that the cGAS-STING pathway is expressed and activated in human pDCs by cytosolic DNA leading to a robust type I IFN response. Direct activation of STING by cyclic dinucleotides including cGAMP also activated pDCs and knockdown of STING abolished this IFN response. These results suggest that pDCs sense cytosolic DNA and cyclic dinucleotides via the cGAS-STING pathway and that targeting this pathway could be of therapeutic interest.

Common Carotid Artery Diameter Responds to Intravenous Volume Expansion: an Ultrasound Observation

SpringerPlus. 2016  |  Pubmed ID: 27386302

In case of intravascular fluid depletion, large veins react to volume expansion with dilation. Little is known about the reaction of arterial vessels. We herein report on the effect of a standardized fluid bolus on the diameter of the common carotid artery (CCA) and its association with hemodynamic parameters, assessed in 20 mechanically ventilated patients after cardiac surgery. CCA was visualized using ultrasound, and the percentage increase in diastolic diameter was calculated by measuring before and after administration of crystalloid infusion solution. Invasive arterial blood pressure and pulse pressure variation (PPV) were assessed in parallel.

[Emergence Delirium in Children - Prophylaxis and Treatment]

Anasthesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie : AINS. Jul, 2016  |  Pubmed ID: 27479259

Emergence Delirium in children after general anesthesia is a common and self limitating event. Although it might be seen as being harmless it can cause other serious complications and might leave both parents and other caregivers with a negative impression behind. Although the cause may still not be clear, potential predictors can be named: preschool age, the use of fast acting volatile anesthestics, higher preoperative anxiety levels and postoperative pain.A child-focused approach to reduce preoperative anxiety focusing on distraction methods rather than pharmacological sedation may be the key as well as sufficient postoperative pain control and the use of total intravenous anesthesia. Parenteal presence during induction of anaesthesia (PPIA) may be beneficial to reduce preoperative anxiety levels, but has failed to prove a better outcome regarding ED.The use of age adopted scores/scales to diagnose ED and Pain are mandatory.In the case of an ED event it is most important to protect the child from self injury and the loss of the iv-line. Postoperative pian needs to be ruled out before treating ED. Most cases can be treated by interrupting the situation and putting the child "back to sleep". Short acting drugs as Propofol have been used successfully due to its pharmacodynamics and short acting profile. Alternatively alpha-agonists or ketamin may be preferred by other authors. If potential predictors and a positive history are present, prophylactic treatment should be considered. A TIVA or the use of alpha-2-agonists have proven to be successful in reducing the risk of an ED. Midazolam may reduce preoperative anxiety but not the incidence of ED and should therefore be used carefully and is not a good choice in PACU for the treatment of ED.Parents who witnessed ED in their children should be guided and followed up. Explaining this phenomenon to parents beforehand should be part of the pre anaesthesia clinic talk and written consent.Standard protocols should be in place for treatment in the postoperative period.

Propofol Pharmacodynamics and Bispectral Index During Key Moments of Awake Craniotomy

Journal of Neurosurgical Anesthesiology. Sep, 2016  |  Pubmed ID: 27681862

During awake craniotomy, the patient's language centers are identified by neurological testing requiring a fully awake and cooperative patient. Hence, anesthesia aims for an unconscious patient at the beginning and end of surgery but an awake and responsive patient in between. We investigated the plasma (Cplasma) and effect-site (Ceffect-site) propofol concentration as well as the related Bispectral Index (BIS) required for intraoperative return of consciousness and begin of neurological testing.

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