Terence Krauß’s research while affiliated with Hannover Medical School and other places

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Publications (16)


Prevention of peri-interventional hypothermia during endoscopic retrograde cholangiopancreatography using a forced-air heating system
  • Conference Paper

April 2024

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8 Reads

Endoscopy

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E. Schuette

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P. Schirmer

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[...]

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H. Lenzen

Flow chart of study participants. Shown are the screening and enrollment of patients into the observational study. Included were adult patients undergoing repeated endoscopic retrograde cholangiopancreatography (ERCP) with an expected sedation duration of more than 30 minutes. The study compared the standard of care (SOC group) with additive use of a forced-air heating system (FAHS group) in a linked comparison.
Temperature-associated endpoints. Shown are primary and secondary temperature-associated clinical outcomes of patients receiving standard-of-care treatment (SOC) and of patients who received additive treatment with a forced-air heating system (FAHS). Temperature course in both groups at the start of sedation and at 10-, 20-, 30-, 40-, and 50-minute sedation time. The mean ± standard error of the mean (SEM). Between-group differences at the same time point are compared using paired t -tests. Within-group longitudinal differences are compared using ANOVA tests. * P < 0.05, ** P < 0.01, *** P < 0.001. Violin plots showing baseline and lowest temperature. Patient maximum absolute body temperature difference (based on the body temperature at the start of sedation and the lowest body temperature during the intervention). Patient maximum relative body temperature difference. Subjective impression of freezing during or following sedation (ranging from 0 to 10 points, with higher scores indicating a more pronounced impression of freezing). Mean room temperatures in both the SOC and the FAHS group.
Parameter associated with occurrence of hypothermia (T<36°C)
Prevention of peri-interventional hypothermia during endoscopic retrograde cholangiopancreatography using a forced-air heating system
  • Article
  • Full-text available

January 2024

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77 Reads

Background and study aims Perioperative hypothermia is associated with significant complications and can be prevented with forced-air heating systems (FAHS). Whether hypothermia occurs during prolonged endoscopic sedation is unclear and prevention measures are not addressed in endoscopic sedation guidelines. We hypothesized that hypothermia also occurs in a significant proportion of patients undergoing endoscopic interventions associated with longer sedation times such as endoscopic retrograde cholangiopancreaticography (ERCP), and that FAHS may prevent it. Patients and methods In this observational study, each patient received two consecutive ERCPs, the first ERCP following current standard of care without FAHS (SOC group) and a consecutive ERCP with FAHS (FAHS group). The primary endpoint was maximum body temperature difference during sedation. Results Twenty-four patients were included. Median (interquartile range) maximum body temperature difference was −0.9°C (−1.2; −0.4) in the SOC and −0.1°C (−0.2; 0) in the FAHS group ( P < 0.001). Median body temperature was lower in the SOC compared with the FAHS group after 20, 30, 40, and 50 minutes of sedation. A reduction in body temperature of > 1°C ( P < 0.001) and a reduction below 36°C ( P = 0.01) occurred more often in the SOC than in the FAHS group. FAHS was independently associated with reduced risk of hypothermia ( P = 0.006). More patients experienced freezing in the SOC group ( P = 0.004). Hemodynmaic and respiratory stability were comparable in both groups. Conclusions Hypothermia occurred in the majority of patients undergoing prolonged endoscopic sedation without active temperature control. FAHS was associated with higher temperature stability during sedation and better patient comfort.

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Study flow chart. VCV: volume controlled ventilation, PCV: pressure controlled ventilation, MV: manual ventilation, FGF: fresh gas flow, HME heat and moisture exchanger
Experimental setup and gas flow diagram of Dräger® Primus®, modified from Drägerwerk AG & Co, Lübeck, Germany with kind permission. APL adjustable pressure limiting, HME heat and moisture exchanger, PEEP positive endexpiratory pressure, pmax maximum pressure, V gas flow sensor, P pressure sensor, IMS ion mobility spectrometer
Results of adult experiments. ppm parts per million. a) 10 l·min− 1 fresh gas flow, pressure controlled ventilation b) 10 l·min− 1 fresh gas flow, volume controlled ventilation c) 18 l·min− 1 fresh gas flow, pressure controlled ventilation d) 18 l·min− 1 fresh gas flow, volume controlled ventilation
Result of pediatric experiments. ppm parts per million. a) 10 l·min− 1 fresh gas flow, pressure controlled ventilation b) 10 l·min− 1 fresh gas flow, volume controlled ventilation c) 18 l·min− 1 fresh gas flow, pressure controlled ventilation d) 18 l·min− 1 fresh gas flow, volume controlled ventilation
Rebounds of sevoflurane concentration during simulated trigger-free pediatric and adult anesthesia

June 2023

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150 Reads

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1 Citation

BMC Anesthesiology

Background In trigger-free anesthesia a volatile anesthetic concentration of 5 parts per million (ppm) should not be exceeded. According to European Malignant Hyperthermia Group (EMHG) guideline, this may be achieved by removing the vapor, changing the anesthetic breathing circuit and renewing the soda lime canister followed by flushing with O2 or air for a workstation specific time. Reduction of the fresh gas flow (FGF) or stand-by modes are known to cause rebound effects. In this study, simulated trigger-free pediatric and adult ventilation was carried out on test lungs including ventilation maneuvers commonly used in clinical practice. The goal of this study was to evaluate whether rebounds of sevoflurane develop during trigger-free anesthesia. Methods A Dräger® Primus® was contaminated with decreasing concentrations of sevoflurane for 120 min. Then, the machine was prepared for trigger-free anesthesia according to EMHG guideline by changing recommended parts and flushing the breathing circuits using 10 or 18 l⋅min− 1 FGF. The machine was neither switched off after preparation nor was FGF reduced. Simulated trigger-free ventilation was performed with volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) including various ventilation maneuvers like pressure support ventilation (PSV), apnea, decreased lung compliance (DLC), recruitment maneuvers, prolonged expiration and manual ventilation (MV). A high-resolution ion mobility spectrometer with gas chromatographic pre-separation was used to measure sevoflurane in the ventilation gas mixture in a 20 s interval. Results Immediately after start of simulated anesthesia, there was an initial peak of 11–18 ppm sevoflurane in all experiments. The concentration dropped below 5 ppm after 2–3 min during adult and 4–18 min during pediatric ventilation. Other rebounds of sevoflurane > 5 ppm occurred after apnea, DLC and PSV. MV resulted in a decrease of sevoflurane < 5 ppm within 1 min. Conclusion This study shows that after guideline-compliant preparation for trigger-free ventilation anesthetic machines may develop rebounds of sevoflurane > 5 ppm during typical maneuvers used in clinical practice. The changes in rate and direction of internal gas flow during different ventilation modes and maneuvers are possible explanations. Therefore, manufacturers should provide machine-specific washout protocols or emphasize the use of active charcoal filters (ACF) for trigger-free anesthesia.


Figure 1. Preoperative hemoglobin and preoperative rSO 2 . rSO 2 = regional oxygen saturation.
Figure 2. Section of the intraoperative course of rSO 2 und MAP (patient A). MAP = mean arterial pressure, rSO 2 = regional oxygen saturation.
Pre- and intraoperative cerebral near-infrared spectroscopy and postoperative delirium: Results of a prospective cross-sectional trial

November 2022

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49 Reads

Medicine

Postoperative delirium (PODE) is a serious complication that can occur during the first few days after surgery. A number of causes can make delirium more likely; one factor to consider is hypoxia during anesthesia. In this study, the pre- and intraoperative cerebral regional oxygen saturation (rSO2) as measured by near-infrared spectroscopy (NIRS) was to be examined with regard to an association with the occurrence of PODE in patients undergoing major abdominal procedures. Data from 80 patients (33 women, 47 men) was examined. The mean age was 66.31 ± 10.55 years (between 42 and 84 years). Thirteen patients developed PODE. The preoperative rSO2 values (P = .10) and the rSO2 values during the steady state of anesthesia (P = .06) tended to be lower in the delirium group than in the non-delirium group. There was a significant correlation between the preoperative rSO2 and the preoperative hemoglobin values (P < .001). The variance of rSO2 during the steady state of anesthesia was significantly greater in the delirium group compared to the non-delirium group (P = .03). In two patients from the delirium group, rSO2 dropped below 50%; they also had a minimum mean arterial pressure below 50 mm Hg, which could have disturbed cerebral autoregulation. The duration of rSO2 decreases (>10%, >15%, >20%) and increases (>10%) compared to the preoperative values was not significantly different between patients with and without PODE. The results suggest that NIRS could be a useful monitoring method for patients undergoing abdominal surgical procedures, on the one hand to recognize patients with low pre- or intraoperative rSO2 values, and on the other hand to detect changes in rSO2 values during anesthesia.



Wash out procedure and simulated trigger-free ventilation of the Atlan A350 using manufacturer’s protocol. Ppm; parts per million. During waiting time for the simulated patient, the machine was set to manual mode with a fresh gas flow of 4 l⋅min− 1. A Desflurane experiment B Sevoflurane experiment
Wash out procedure and simulated trigger-free ventilation of the Carestation 650 using manufacturer’s protocol. Ppm; parts per million. During waiting time for the simulated patient, the machine was set to manual mode with a fresh gas flow of 4 l⋅min− 1. A Desflurane experiment B Sevoflurane experiment
Wash out procedure and simulated trigger-free ventilation of the Carestation 650 using manufacturer’s protocol with surplus exchange of the breathing system and bellows. Ppm; parts per million. During waiting time for the simulated patient, the machine was set to manual mode with a fresh gas flow of 4 l⋅min− 1. A Desflurane experiment B Sevoflurane experiment
Preparation of Dräger Atlan A350 and General Electric Healthcare Carestation 650 anesthesia workstations for malignant hyperthermia susceptible patients

December 2021

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692 Reads

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3 Citations

BMC Anesthesiology

Abstract Background Patients at risk of malignant hyperthermia need trigger-free anesthesia. Therefore, anesthesia machines prepared for safe use in predisposed patients should be free of volatile anesthetics. The washout time depends on the composition of rubber and plastic in the anesthesia machine. Therefore, new anesthesia machines should be evaluated regarding the safe preparation for trigger-free anesthesia. This study investigates wash out procedures of volatile anesthetics for two new anesthetic workstations: Dräger Atlan A350 and General Electric Healthcare (GE) Carestation 650 and compare it with preparation using activated charcoal filters (ACF). Methods A Dräger Atlan and a Carestation 650 were contaminated with 4% sevoflurane for 90 min. The machines were decontaminated with method (M1): using ACF, method 2 (M2): a wash out method that included exchange of internal parts, breathing circuits and soda lime canister followed by ventilating a test lung using a preliminary protocol provided by Dräger or method 3 (M3): a universal wash out instruction of GE, method 4 (M4): M3 plus exchange of breathing system and bellows. Decontamination was followed by a simulated trigger-free ventilation. All experiments were repeated with 8% desflurane contaminated machines. Volatile anesthetics were detected with a closed gas loop high-resolution ion mobility spectrometer with gas chromatographic pre-separation attached to the bacterial filter of the breathing circuits. Primary outcome was time until


(A) Burst suppression. (B,C) Epileptiform potentials recorded in two patients.
High Incidence of Epileptiform Potentials During Continuous EEG Monitoring in Critically Ill COVID-19 Patients

March 2021

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66 Reads

Objective: To analyze continuous 1- or 2-channel electroencephalograms (EEGs) of mechanically ventilated patients with coronavirus disease 2019 (COVID-19) with regard to occurrence of epileptiform potentials. Design: Single-center retrospective analysis. Setting: Intensive care unit of Hannover Medical School, Hannover, Germany. Patients: Critically ill COVID-19 patients who underwent continuous routine EEG monitoring (EEG monitor: Narcotrend-Compact M) during sedation. Measurements and Main Results: Data from 15 COVID-19 patients (11 men, four women; age: 19–75 years) were evaluated. Epileptiform potentials occurred in 10 of 15 patients (66.7%). Conclusions: The results of the evaluation regarding the occurrence of epileptiform potentials show that there is an unusually high percentage of cerebral involvement in patients with severe COVID-19. EEG monitoring can be used in COVID-19 patients to detect epileptiform potentials.


Figure 3. Range of the median Narcotrend Index at different patient ages. The bold black lines within each bar represent the medians of the ranges.
Figure 4. Range of the median Narcotrend Index at different MAC values of sevoflurane. The bold black lines within each bar represent the medians of the ranges. MAC = minimum alveolar concentration.
Figure 5. EEG graphs during the steady state of anaesthesia as observed in different patients. (A) EEG at NI of 79, (B) suppression EEG, (C) epileptiform discharges. EEG = electroencephalogram.
Intraoperative monitoring parameters and postoperative delirium: Results of a prospective cross-sectional trial

January 2021

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156 Reads

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16 Citations

Medicine

Postoperative delirium (PODE) can be associated with severe clinical complications; therefore, preventive measures are important. The objective of this trial was to elucidate whether haemodynamic or electroencephalographic (EEG) monitoring parameters during general anaesthesia or sevoflurane dosage correlate with the incidence of PODE. In addition, sevoflurane dosages and EEG stages during the steady state of anaesthesia were analyzed in patients of different ages. Eighty adult patients undergoing elective abdominal surgery received anaesthesia with sevoflurane and sufentanil according to the clinical routine. Anaesthesiologists were blinded to the EEG. Haemodynamic parameters, EEG parameters, sevoflurane dosage, and occurrence of PODE were analyzed. Thirteen patients (4 out of 33 women, 9 out of 47 men) developed PODE. Patients with PODE had a greater mean arterial pressure (MAP) variance (267.26 (139.40) vs 192.56 (99.64) mmHg², P = .04), had a longer duration of EEG burst suppression or suppression (27.09 (45.32) vs 5.23 (10.80) minutes, P = .03), and received higher minimum alveolar sevoflurane concentrations (MAC) (1.22 (0.22) vs 1.09 (0.17), P = .03) than patients without PODE. MAC values were associated with wide ranges of EEG index values representing different levels of hypnosis. The results suggest that, in order to prevent PODE, a great variance of MAP, higher doses of sevoflurane, and deep levels of anaesthesia should be avoided. Titrating sevoflurane according to end-tidal gas monitoring and vital signs can lead to unnecessarily deep or light hypnosis. Intraoperative EEG monitoring may help to prevent PODE.


Preparation of anaesthesia workstation for trigger-free anaesthesia: An observational laboratory study

September 2019

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81 Reads

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16 Citations

European Journal of Anaesthesiology

Background: Trigger-free anaesthesia is required for patients who are susceptible to malignant hyperthermia. Therefore, all trace of volatile anaesthetics should be removed from anaesthetic machines before induction of anaesthesia. Because the washout procedure is time consuming, activated charcoal filters (ACFs) have been introduced, but never tested under minimal flow conditions. Objective(s): The current study aims to investigate performance of ACFs during long duration (24 h) simulated ventilation. Design: A bench study. Setting: A Primus anaesthesia machine (Dräger) was contaminated with either 4% sevoflurane or 8% desflurane by ventilating a test lung for 90 min. The machine was briefly flushed according to manufacturer instructions, ACFs were inserted and a test lung was ventilated in a 24 h test. Trace gas concentrations were measured using a closed gas loop high-resolution ion mobility spectrometer with gas chromatographic preseparation. During the experiment reduced fresh gas flows (FGFs) were tested. At the end of each experiment the ACFs were removed and the machine was set to standby for 10 min to test for residual contamination within the circuit. and then the ACFs were reconnected into the circuit to test their ability to continue removing volatile anaesthetics (functional test) from the gas. Control experiments were conducted without ACFs. Main outcome measures: Absolute concentrations of desflurane and sevoflurane. Results: The concentration of volatile anaesthetics dropped to less than 5 ppm (parts per million) following insertion of ACFs. In the desflurane experiments at least 1 l min FGF was needed to keep the concentration below an acceptable level (<5 ppm): 0.5 l min FGF was required in sevoflurane experiments. While ACFs in the sevoflurane tests passed the functional test after 24 h, ACFs in the desflurane tests failed. Conclusion: ACFs meet the requirements for trigger-free low flow (1 l min) ventilation over 24 h. Minimal flow (0.5 l min) ventilation may be possible for sevoflurane contaminated machines.


Citations (10)


... Des Weiteren wird die IMS für die Überwachung medizinischer Biomarker [11][12][13], in die Lebensmittelsicherheit [14][15][16] sowie jüngst für die Analyse von Biogas genutzt [17]. Im medizinischen Bereich kommt die IMS auch zur Bestimmung der Arbeitsplatzkonzentration volatiler Anästhesiegase in Aufwachräumen zum Einsatz [18; 19], hier insbesondere zur Quantifizierung der Restkonzentration volatiler Anästhetika bei "triggerfreier" Allgemeinanästhesie [20][21][22][23]. ...

Reference:

P23 - Ionenmobilitätsspektrometrie mit Gaschromatographie zur Bewertung von Narkoseabgasabsorbern bei Anästhesiegeräten ohne zentrale Narkosegasabsaugung
Rebounds of sevoflurane concentration during simulated trigger-free pediatric and adult anesthesia

BMC Anesthesiology

... International guidelines propose three approaches to avoid exposure to a residual volatile anesthetic: 1) a vapor-free workstation clearly labelled and reserved for anesthesia without volatile anesthetics as an option readily available for emergencies, 2) use of activated charcoal filters and removal of the vaporizer from the workstation, and 3) removal of the vaporizer and changing the breathing circuit to an uncontaminated new and complete set followed by flushing with 100% oxygen (O 2 ) according to manufacturer instructions [1,2]. ...

Preparation of Dräger Atlan A350 and General Electric Healthcare Carestation 650 anesthesia workstations for malignant hyperthermia susceptible patients

BMC Anesthesiology

... 4 It has been reported that burst suppression, defined as alternating episodes of isoelectric flat electroencephalogram (EEG) periods with bursts of slow waves, 5 may predict postoperative delirium. [5][6][7][8][9][10][11][12][13][14] Older age is a known risk factor for both postoperative delirium in adults 13 and in increasing burst suppression occurrence. 15 Most studies evaluating burst suppression have relied on processed EEG indices from commercially avail-able monitors, such as the patient state index (PSI) of the SEDLine monitor or the bispectral index (BIS) monitor. ...

Intraoperative monitoring parameters and postoperative delirium: Results of a prospective cross-sectional trial

Medicine

... In case of emergency surgical operations, the use of activated charcoal filters can save money and time. Thoben et al. observed that activated charcoal filters meet the requirements for trigger-free low flow ventilation over 24 h [11]. There is no need for an additional exchange of the soda and the breathing system, which would otherwise result in a further delay for the commissioning of the anesthesia workstation [2]. ...

Preparation of anaesthesia workstation for trigger-free anaesthesia: An observational laboratory study
  • Citing Article
  • September 2019

European Journal of Anaesthesiology

... Finally, two recent studies were conducted using ion mobility spectrometry (IMS), [68,69]. Many different technologies are available within this field, such as GC-IMS or pre-separation by a multi-capillary column (MCC-IMS). ...

Low anaesthetic waste gas concentrations in postanaesthesia care unit: A prospective observational study
  • Citing Article
  • February 2018

European Journal of Anaesthesiology

... Recovery rates are higher in women with mature teratoma (88%) than immature teratoma (76%) [21]. In refractory cases where imaging is negative and antibodies are positive, an exploratory laparotomy may be considered to rule out microscopic teratoma, although this issue remains controversial [22]. Due to the rarity of the condition, screening for anti-NMDAR antibodies in patients with ovarian teratoma is not indicated currently [23]. ...

Ovarectomy despite Negative Imaging in Anti-NMDA Receptor Encephalitis: Effective Even Late

... Sharp and spike waves can be combined with slow waves. Some studies have reported that epileptiform discharges are frequently observed during general anesthesia induction with sevoflurane (Vakkuri et al., 2001;Schultz et al., 2012). According to Vakkuri et al., the following types of epileptiform discharges were described during sevoflurane induction: delta with spikes (DSP), rhythmic polyspikes (PSR), periodic epileptiform discharges (PED), and suppression with spikes (Vakkuri et al., 2001). ...

Incidence of Epileptiform EEG Activity in Children during Mask Induction of Anaesthesia with Brief Administration of 8% Sevoflurane

... Most studies had a similar onset time on the adductor pollicis, compared with our results on the arm muscles, as noted during the introduction of the TOF-Cuff, which is similar to the adductor pollicis [5,9,10,[15][16][17][18]. However, compared with other studies, we obtained a shorter onset time in the corrugator supercilii muscle [5,[18][19][20][21]. ...

Propofol, remifentanil and mivacurium: Fast track surgery with poor intubating conditions
  • Citing Article
  • June 2011

Minerva Anestesiologica

... В аналогичном исследовании с ксеноном авторы выяви ли еще более высокую корреляцию между визуальной и автоматической оценкой (r = 0,957), но при этом от метили прямую связь активности ЭЭГ в диапазоне низ ких частот (дельта волны [δволны]) с очень глубокими стадиями наркоза, в отличие от анестезии пропофолом. По мнению авторов, мониторинг ЭЭГ должен быть обя зательным элементом наркозных аппаратов для анесте зии ксеноном [12]. Цель исследования -оценить возможность при менения шкалы Kugler на основании данных ЭЭГ как алгоритма объективной оценки глубины угнетения со знания ксеноном в комбинации с наркотическими аналь гетиками или без них, в сочетании с регионарной блока дой во время операции эндопротезирования коленного сустава у пациентов пожилого и старческого возраста. ...

Assessing the depth of hypnosis of xenon anaesthesia with the EEG
  • Citing Article
  • February 2010

... There is still debate regarding precise determination of propofol dosage, bearing in mind lots of potentially relevant factors. In regard with the patients' sex, majority of studies reported that women needed more propofol for the same level of consciousness and that they emerged faster than men from propofol anaesthesia [20][21][22][23][24][25] . However, Choi et al 26 found that male patients require a higher dose of propofol than female for I-gel insertion. ...

Women need more propofol than men during EEG-monitored total intravenous anaesthesia / Frauen benötigen mehr Propofol als Männer während EEG-überwachter total-intravenöser Anästhesie
  • Citing Article
  • May 2009