Inhaled isoflurane via the anaesthetic conserving device versus propofol for sedation of invasively ventilated patients in intensive care units in Germany and Slovenia: an open-label, phase 3, randomised controlled, non-inferiority trial.

BACKGROUND: Previous studies indicate that isoflurane could be useful for the sedation of patients in the intensive care unit (ICU), but prospective studies evaluating isoflurane's efficacy have been small. The aim of this study was to test whether the sedation with isoflurane was non-inferior to sedation with propofol. METHODS: This phase 3, randomised, controlled, open-label non-inferiority trial evaluated the efficacy and safety of up to 54 h of isoflurane compared with propofol in adults (aged ≥18 years) who were invasively ventilated in ICUs in Germany (21 sites) and Slovenia (three sites). Patients were randomly assigned (1:1) to isoflurane inhalation via the Sedaconda anaesthetic conserving device (ACD; Sedana Medical AB, Danderyd, Sweden; ACD-L [dead space 100 mL] or ACD-S [dead space 50 mL]) or intravenous propofol infusion (20 mg/mL) for 48 h (range 42-54) using permuted block randomisation with a centralised electronic randomisation system. The primary endpoint was percentage of time in Richmond Agitation-Sedation Scale (RASS) range -1 to -4, assessed in eligible participants with at least 12 h sedation (the per-protocol population), five or more RASS measurements, and no major protocol violations, with a non-inferiority margin of 15%. Key secondary endpoints were opioid requirements, spontaneous breathing, time to wake-up and extubation, and adverse events. Safety was assessed in all patients who received at least one dose. The trial is complete and registered with EudraCT, 2016-004551-67. FINDINGS: Between July 2, 2017, and Jan 12, 2020, 338 patients were enrolled and 301 (89%) were randomly assigned to isoflurane (n=150) or propofol (n=151). 146 patients (97%) in each group completed the 24-h follow-up. 146 (97%) patients in the isoflurane group and 148 (98%) of patients in the propofol group were included in the per-protocol analysis of the primary endpoint. Least-squares mean percentage of time in RASS target range was 90·7% (95% CI 86·8-94·6) for isoflurane and 91·1% (87·2-95·1) for propofol. With isoflurane sedation, opioid dose intensity was 29% lower than with propofol for the overall sedation period (0·22 [0·12-0·34] vs 0·32 [0·21-0·42] mg/kg per h morphine equivalent dose, p=0·0036) and spontaneous breathing was more frequent on day 1 (odds ratio [OR] 1·72 [1·12-2·64], generalised mixed linear model p=0·013, with estimated rates of 50% of observations with isoflurane vs 37% with propofol). Extubation times were short and median wake-up was significantly faster after isoflurane on day 2 (20 min [IQR 10-30] vs 30 min [11-120]; Cox regression p=0·0011). The most common adverse events by treatment group (isoflurane vs propofol) were: hypertension (ten [7%] of 150 vs two [1%] of 151), delirium (eight [5%] vs seven [5%]), oliguria (seven [5%] vs six [4%]), and atrial fibrillation (five [3%] vs four [3%]). INTERPRETATION: These results support the use of isoflurane in invasively ventilated patients who have a clinical need for sedation. FUNDING: Sedana Medical AB.

Pain in children undergoing tonsillotomy with alternating ibuprofen and paracetamol - a prospective observational study.

BACKGROUND: The optimal pain therapy for children undergoing tonsillotomy remains unknown. Our aim was to evaluate a standard pain therapy including the alternating application of ibuprofen and paracetamol. METHODS: Pain intensity of 81 in-patients after tonsillotomy aged 2-12 years was evaluated three times daily (mean observation 3.85 days) using the Children's and Infants' Postoperative Pain Scale (CHIPPS) in children <5 years, or with the Faces Pain Scale-Revised (FPS-R) in older children. Parents completed the Parents' Postoperative Pain Measure (PPPM-D) in addition. Exceeding the cut-off value in one of the scores implied the indication for an opioid rescue medication (RM). Endpoints were number of children with indication for the RM, course of pain, concordance between pain scales, and adverse events. RESULTS: Overall, 45.7% of children needed the RM either in the recovery room or on the ward. The rate of children having an indication for RM on the ward was 30.9%. The highest proportion of affected children was identified on the day of surgery (32.1%). Most indications were detected with the PPPM-D only. A comparison with an earlier study showed less affected children compared to ibuprofen monotherapy on the day of surgery and the first postoperative day. Eleven children (13.6%) developed fever. CONCLUSION: Although our pain therapy concept was effective from postoperative day 1 onwards, it needs improvement for the day of surgery. The overall concordance between the PPPM-D and CHIPPS or FPS-R was low. Fever might be a confounder for the pain intensity measurement with the PPPM-D.

Spontaneous breathing for managing analgesia during balanced anesthesia with remifentanil and desflurane: a prospective, single center randomized controlled trial.

The main goal of anesthesiology is to achieve the best level of analgesia and a fast recovery of consciousness following anesthesia. The preservation of spontaneous breathing during general anesthesia with anesthetic gases is practiced by many anesthetists. However, very few studies have dealt with these positive properties of volatile anesthetics such as sevoflurane or desflurane. Remifentanil is a very short half-life opiate that combines sufficient intra-operative analgesia with a fast post-operative recovery time. We tested the hypothesis that spontaneous breathing can reduce overdosing with remifentanil during desflurane anesthesia. In this prospective, single center, multiple anesthetist study, 30 patients were randomized into two groups (volume-controlled ventilation mode and spontaneous breathing). The spontaneous breathing group showed a significantly lower post-operative pain level than the volume-controlled ventilation mode group. Furthermore, less remifentanil as well as less piritramide was needed in the spontaneous breathing group compared with volume-controlled ventilation mode. It was possible to achieve spontaneous breathing in all patients with 0.6 minimum alveolar concentration desflurane, in order to control the remifentanil rate and prevent an overdose. All spontaneous breathing patients had low intra- and post-operative pain levels and the need for analgesics was equal to or lower than that in the volume-controlled ventilation mode group. By reducing the intra-operative amount of opiates, both the post-operative pain and the amount of post-operative analgesia required can be reduced. A balanced anesthesia with spontaneous intra-operative breathing is needed to determine the required amount of opiates. This study was approved by the Ethic Committee of the Ruhr-University of Bochum (approval No. 2435) in September, 2004.

Teriflunomide provides protective properties after oxygen-glucose-deprivation in hippocampal and cerebellar slice cultures.

One of the major challenges in emergency medicine is out-of-hospital cardiac arrest (OHCA). Every year, about 53-62/100 000 people worldwide suffer an out-of-hospital cardiac arrest with serious consequences, whereas persistent brain injury is a major cause of morbidity and mortality of those surviving a cardiac arrest. Today, only few and insufficient strategies are known to limit neurological damage of ischemia and reperfusion injury. The aim of the present study was to investigate whether teriflunomide, an approved drug for treatment of relapsing-remitting-multiple-sclerosis, exerts a protective effect on brain cells in an in vitro model of ischemia. Therefore, organotypic slice cultures from rat hippocampus and cerebellum were exposed to oxygen-glucose-deprivation and subsequently treated with teriflunomide. The administration of teriflunomide in the reperfusion time on both hippocampal and cerebellar slice cultures significantly decreased the amount of detectable propidium iodide signal compared with an untreated culture, indicating that more cells survive after oxygen-glucose-deprivation. However, hippocampal slice cultures showed a higher vulnerability to ischemic conditions and a more sensitive response to teriflunomide compared with cerebellar slice cultures. Our study suggests that teriflunomide, applied as a post-treatment after an oxygen-glucose-deprivation, has a protective effect on hippocampal and cerebellar cells in organotypic slice cultures of rats. All procedures were conducted under established standards of the German federal state of North Rhine Westphalia, in accordance with the European Communities Council Directive 2010/63/EU on the protection of animals used for scientific purposes.

Incidence of infection in non-tunnelled thoracic epidural catheters after major abdominal surgery.

BACKGROUND: Thoracic epidural analgesia is beneficial after major abdominal surgery, though side-effects and complications are rare but potentially devastating. The incidence of catheter-related infection is approximately 5.5%. Several guidelines have been recommended to prevent complications during thoracic epidural catheterization. Tunnelling is often recommended to reduce the incidence of infections and dislocations. METHODS: A retrospective, single-centre analysis of our acute pain service database was performed between 2010 and 2018. The hygiene measures of the German Society of Anaesthesiology have been incorporated in our standard operating protocol since 2009. The procedure remained constant, but the skin disinfectant was changed from propan-2-ol to propan-2-ol with octenidine in 2014. Tunnelling of catheters was not performed. We analysed the incidence of catheter-related infections (primary endpoint) and effect of the used disinfectant (secondary endpoint). RESULTS: A total of 2755 patients underwent elective major abdominal surgery with thoracic epidural catheterization. Sixteen patients (0.6%) showed symptoms of mild catheter-related infection. Moderate or severe infections were not observed in any patient. The type of disinfectant did not show any significant effect on the incidence of infection. CONCLUSION: The incidence of catheter-related infections was low, and only mild signs of infection were observed. Non-tunnelling could be an alternative to tunnelling, especially if hygiene protocols are followed, and the duration of catheter use is short. A comprehensive database and regular examinations by trained staff are essential for early detection of abnormalities and immediate removal of the catheter, if required.

High dose ibuprofen as a monotherapy on an around-the-clock basis fails to control pain in children undergoing tonsil surgery: a prospective observational cohort study.

PURPOSE: The optimal pain management concept in children after tonsil surgery is controversial. Ibuprofen on an "around-the-clock" basis has been suggested to control postoperative pain sufficiently. Therefore, we established a standard scheme with weight-adapted recommended maximum ibuprofen dose. A reliable assessment of pain intensity can be performed with the Children's and Infants' Postoperative Pain Scale (CHIPPS) in children < 5 years, or with the Faces Pain Scale-Revised (FPS-R) in children aged ≥ 5 years. The Parents' Postoperative Pain Measure (PPPM-D) may be a useful tool for both age groups. We hypothesized that not more than 30% of the children would need an opioid rescue medication during their in-hospital stay and analyzed the consistency of the PPPM-D with other pain scales. METHODS: We included 158 in-patients aged 2-12 years. Ibuprofen was orally administered every 8 h. Three times daily, pain scores were assessed by CHIPPS or FPS-R, respectively. The PPPM-D was used in all children. Exceeding the cut-off value in one of the tools was regarded as relevant pain. RESULTS: A rescue medication was needed in 82.1% of children after tonsillectomy and 51.3% of children after tonsillotomy (P < 0.001). The cut-off value for relevant pain was mostly exceeded in the PPPM-D, but its overall concordance to the reference scales was low. CONCLUSION: High-dose ibuprofen "around-the-clock" is insufficient to control pain in children after tonsil surgery. Research is needed to find an optimal schema for management and assessment of postoperative pain.

Improvement in pre-operative risk assessment in adults undergoing noncardiac surgery by a process-oriented score: A prospective single-centre study.

BACKGROUND: Pre-operative risk assessment is important to quantify the patient's risks of morbidity and mortality, but its quality differs. We created a process-oriented score (PRO-score) for risk evaluation of adults as a three-stage warning score checklist with concrete guidance. It contains the contents of current guidelines and the assessment of vital signs. OBJECTIVES: We investigated whether the PRO-score is suitable to detect 'red flag' warning signs not only in American Society of Anesthesiologists (ASA) physical status (PS) 3 or 4 patients but also in ASA-PS 1 or 2 patients. Resulting medical, therapeutic or structural consequences were recorded. DESIGN: Prospective single-centre study. SETTING: The study was performed in a German university hospital between November 2015 and December 2018. PATIENTS: We included 54 455 adult patients undergoing a pre-operative risk assessment for general or regional anaesthesia and elective noncardiac surgery. RESULTS: In all, 388 patients presented 'red flag' warning signs in the PRO-score during risk assessment; 85 (21.9%) were labelled ASA-PS 1 or 2, 244 (62.9%) ASA-PS 3 and 59 (15.2%) ASA-PS 4. Additional examinations were performed in 179 patients and technical tests in 175 patients (ASA-PS 1 or 2: 53 and 63 patients, respectively). After re-evaluation of the peri-operative risk in an interdisciplinary conference, surgery was cancelled in 44 patients (ASA-PS 1 and 2, 17 patients) or performed under local anaesthesia in 15 patients (ASA-PS 1 and 2, 2 patients). A downgrading to PRO-score 2 was reached in 168 patients after therapeutic interventions (ASA-PS 1 and 2, 54 patients). Undergoing surgery despite 'red flag' events resulted in major complications in 34 patients, and 16 patients died (ASA-PS 1 or 2: 7 and 3 patients, respectively). CONCLUSION: The PRO-score detected warning signs in 'healthy' ASA-PS 1 or 2 and in ASA-PS 3 or 4 patients. Furthermore, it influenced the management of these patients, and thus improved the process quality of risk assessment. The physical examination should include the assessment of vital signs.

Comparison of 3 Methods to Assess Occupational Sevoflurane Exposure in Abdominal Surgeons: A Single-Center Observational Pilot Study.

BACKGROUND: Studies demonstrated that operating room personnel are exposed to anesthetic gases such as sevoflurane (SEVO). Measuring the gas burden is essential to assess the exposure objectively. Air pollution measurements and the biological monitoring of urinary SEVO and its metabolite hexafluoroisopropanol (HFIP) are possible approaches. Calculating the mass of inhaled SEVO is an alternative, but its predictive power has not been evaluated. We investigated the SEVO burdens of abdominal surgeons and hypothesized that inhaled mass calculations would be better suited than pollution measurements in their breathing zones (25 cm around nose and mouth) to estimate urinary SEVO and HFIP concentrations. The effects of potentially influencing factors were considered. METHODS: SEVO pollution was continuously measured by photoacoustic gas monitoring. Urinary SEVO and HFIP samples, which were collected before and after surgery, were analyzed by a blinded environmental toxicologist using the headspace gas chromatography-mass spectrometry method. The mass of inhaled SEVO was calculated according to the formula mVA = cVA·(Equation is included in full-text article.)·t·ρ VA aer. (mVA: inhaled mass; cVA: volume concentration; (Equation is included in full-text article.): respiratory minute volume; t: exposure time; and ρ VA aer.: gaseous density of SEVO). A linear multilevel mixed model was used for data analysis and comparisons of the different approaches. RESULTS: Eight surgeons performed 22 pancreatic resections. Mean (standard deviation [SD]) SEVO pollution was 0.32 ppm (0.09 ppm). Urinary SEVO concentrations were below the detection limit in all samples, whereas HFIP was detectable in 82% of the preoperative samples in a mean (SD) concentration of 8.53 µg·L (15.53 µg·L; median: 2.11 µg·L, interquartile range [IQR]: 4.58 µg·L) and in all postoperative samples (25.42 µg·L [21.39 µg·L]). The mean (SD) inhaled SEVO mass was 5.67 mg (2.55 mg). The postoperative HFIP concentrations correlated linearly to the SEVO concentrations in the surgeons' breathing zones (ß = 216.89; P < .001) and to the calculated masses of inhaled SEVO (ß = 4.17; P = .018). The surgeon's body mass index (BMI), age, and the frequency of surgeries within the last 24 hours before study entry did not influence the relation between HFIP concentration and air pollution or inhaled mass, respectively. CONCLUSIONS: The biological SEVO burden, expressed as urinary HFIP concentration, can be estimated by monitoring SEVO pollution in the personnel's individual breathing zone. Urinary SEVO was not an appropriate biomarker in this setting.

Use of MIRUS™ for MAC-driven application of isoflurane, sevoflurane, and desflurane in postoperative ICU patients: a randomized controlled trial.

BACKGROUND: The MIRUS™ (TIM, Koblenz, Germany) is an electronical gas delivery system, which offers an automated MAC (minimal alveolar concentration)-driven application of isoflurane, sevoflurane, or desflurane, and can be used for sedation in the intensive care unit. We investigated its consumption of volatile anesthetics at 0.5 MAC (primary endpoint) and the corresponding costs. Secondary endpoints were the technical feasibility to reach and control the MAC automatically, the depth of sedation at 0.5 MAC, and awakening times. Mechanically ventilated and sedated patients after major surgery were enrolled. Upon arrival in the intensive care unit, patients obtained intravenous propofol sedation for at least 1 h to collect ventilation and blood gas parameters, before they were switched to inhalational sedation using MIRUS™ with isoflurane, sevoflurane, or desflurane. After a minimum of 2 h, inhalational sedation was stopped, and awakening times were recorded. A multivariate electroencephalogram and the Richmond Agitation Sedation Scale (RASS) were used to assess the depth of sedation. Vital signs, ventilation parameters, gas consumption, MAC, and expiratory gas concentrations were continuously recorded. RESULTS: Thirty patients obtained inhalational sedation for 18:08 [14:46-21:34] [median 1st-3rd quartiles] hours. The MAC was 0.58 [0.50-0.64], resulting in a Narcotrend Index of 37.1 [30.9-42.4] and a RASS of - 3.0 [- 4.0 to (- 3.0)]. The median gas consumption was significantly lowest for isoflurane ([ml h-1]: isoflurane: 3.97 [3.61-5.70]; sevoflurane: 8.91 [6.32-13.76]; and desflurane: 25.88 [20.38-30.82]; p < 0.001). This corresponds to average costs of 0.39 € h-1 for isoflurane, 2.14 € h-1 for sevoflurane, and 7.54 € h-1 for desflurane. Awakening times (eye opening [min]: isoflurane: 9:48 [4:15-20:18]; sevoflurane: 3:45 [0:30-6:30]; desflurane: 2:00 [1:00-6:30]; p = 0.043) and time to extubation ([min]: isoflurane: 10:10 [8:00-20:30]; sevoflurane: 7:30 [4:37-14:22]; desflurane: 3:00 [3:00-6:00]; p = 0.007) were significantly shortest for desflurane. CONCLUSIONS: A target-controlled, MAC-driven automated application of volatile anesthetics is technically feasible and enables an adequate depth of sedation. Gas consumption was highest for desflurane, which is also the most expensive volatile anesthetic. Although awakening times were shortest, the actual time saving of a few minutes might be negligible for most patients in the intensive care unit. Thus, using desflurane seems not rational from an economic perspective. Trial registration Clinical Trials Registry (ref.: NCT03860129). Registered 24 September 2018-Retrospectively registered.

Photoacoustic gas monitoring for anesthetic gas pollution measurements and its cross-sensitivity to alcoholic disinfectants.

BACKGROUND: Real-time photoacoustic gas monitoring is used for personnel exposure and environmental monitoring, but its accuracy varies when organic solvents such as alcohol contaminate measurements. This is problematic for anesthetic gas measurements in hospitals, because most disinfectants contain alcohol, which could lead to false-high gas concentrations. We investigated the cross-sensitivities of the photoacoustic gas monitor Innova 1412 (AirTech Instruments, LumaSense, Denmark) against alcohols and alcoholic disinfectants while measuring sevoflurane, desflurane and isoflurane in a laboratory and in hospital during surgery. METHODS: 25 mL ethyl alcohol was distributed on a hotplate. An optical filter for isoflurane was used and the gas monitor measured the 'isoflurane' concentration for five minutes with the measuring probe fixed 30 cm above the hotplate. Then, 5 mL isoflurane was added vaporized via an Anesthetic Conserving Device (Sedana Medical, Uppsala, Sweden). After one-hour measurement, 25 mL isopropyl alcohol, N-propanol, and two alcoholic disinfectants were subsequently added, each in combination with 5 mL isoflurane. The same experiment was in turn performed for sevoflurane and desflurane. The practical impact of the cross-sensitivity was investigated on abdominal surgeons who were exposed intraoperatively to sevoflurane. A new approach to overcome the gas monitor's cross-sensitivity is presented. RESULTS: Cross-sensitivity was observed for all alcohols and its strength characteristic for the tested agent. Simultaneous uses of anesthetic gases and alcohols increased the concentrations and the recovery times significantly, especially while sevoflurane was utilized. Intraoperative measurements revealed mean and maximum sevoflurane concentrations of 0.61 ± 0.26 ppm and 15.27 ± 14.62 ppm. We replaced the cross-sensitivity peaks with the 10th percentile baseline of the anesthetic gas concentration. This reduced mean and maximum concentrations significantly by 37% (p < 0.001) and 86% (p < 0.001), respectively. CONCLUSION: Photoacoustic gas monitoring is useful to detect lowest anesthetic gases concentrations, but cross-sensitivity caused one third falsely high measured mean gas concentration. One possibility to eliminate these peaks is the recovery time-based baseline approach. Caution should be taken while measuring sevoflurane, since marked cross-sensitivity peaks are to be expected.

Kinetics of isoflurane and sevoflurane in a unidirectional displacement flow and the relevance to anesthetic gas exposure by operating room personnel.

International guidelines recommend the use of ventilation systems in operating rooms to reduce the concentration of potentially hazardous substances such as anesthetic gases. The exhaust air grilles of these systems are typically located in the lower corners of the operating room and pick up two-thirds of the air volume, whereas the final third is taken from near the ceiling, which guarantees an optimal perfusion of the operating room with a sterile filtered air supply. However, this setup is also employed because anesthetic gases have a higher molecular weight than the components of air and should pool on the floor if movement is kept to a minimum and if a ventilation system with a unidirectional displacement flow is employed. However, this anticipated pooling of volatile anesthetics at the floor level has never been proven. Thus, we herein investigated the flow behaviors of isoflurane, sevoflurane, and carbon dioxide (for comparison) in a measuring chamber sized 2.46 × 1.85 × 5.40 m with a velocity of 0.3 m/sec and a degree of turbulence <20%. Gas concentrations were measured at 1,728 measuring positions throughout the measuring chamber, and the flow behaviors of isoflurane and sevoflurane were found to be similar, with an overlap of 90%. The largest spread of both gases was 55 cm at 5.4 m from the emission source. Interestingly, neither isoflurane nor sevoflurane was detected at floor level, but a continuous cone-like spreading was observed due to gravity. In contrast, carbon dioxide accumulated at floor level in the form of a gas cloud. Thus, floor level exhaust ventilation systems are likely unsuitable for the collection and removal of anesthetic gases from operating rooms.

The Personnel's Sevoflurane Exposure in the Postanesthesia Care Unit Measured by Photoacoustic Gas Monitoring and Hexafluoroisopropanol Biomonitoring.

PURPOSE: Room ventilation in the postanesthesia care unit (PACU) is often poor, although patients exhale anesthetic gases. We investigated the PACU personnel's environmental and biological sevoflurane (SEVO) burden during patient care. DESIGN: Prospective, observational study. METHODS: Air pollution was measured by photoacoustic gas monitoring in the middle of the PACU, above the patient's face, and on the PACU corridor. Urinary SEVO and hexafluoroisopropanol concentrations were determined. FINDINGS: Mean air pollution was 0.34 ± 0.07 ppm in the middle of the PACU, 0.56 ± 0.17 ppm above the patient's face, and 0.47 ± 0.06 ppm on the corridor. Biological preshift exposure levels were 0.13 ± 0.03 mcg/L (SEVO) and 4.72 ± 5.41 mcg/L (hexafluoroisopropanol). Postshift concentrations increased significantly to 0.20 ± 0.06 mcg/L (P = .004) and 42.18 ± 27.82 mcg/L (P < .001). CONCLUSIONS: PACU personnel were environmentally and biologically exposed to SEVO, but exposure levels were minimal according to current recommendations.

Environmental safety: Air pollution while using MIRUS™ for short-term sedation in the ICU.

BACKGROUND: MIRUS™ is a device for target-controlled inhalational sedation in the ICU in combination with use of isoflurane, or sevoflurane, or desflurane. The feasibility of this device has recently been proven; however, ICU staff exposure may restrict its application. We investigated ICU ambient room pollution during daily work to estimate ICU personnel exposure while using MIRUS™. METHODS: This observational study assessed pollution levels around 15 adult surgical patients who received volatile anaesthetics-based sedation for a median of 11 hours. Measurements were performed by photoacoustic gas monitoring in real-time at different positions near the patient and in the personnel's breathing zone. Additionally, the impact of the Clean Air™ open reservoir scavenging system on volatile agent pollution was evaluated. RESULTS: Baseline concentrations [ppm] during intervention and rest periods were isoflurane c¯mean = 0.58 ± 0.49, c¯max = 5.72; sevoflurane c¯mean = 0.22 ± 0.20, c¯max = 7.93; and desflurane c¯mean = 0.65 ± 0.57, c¯max = 6.65. Refilling MIRUS™ with liquid anaesthetic yielded gas concentrations of c¯mean = 2.18 ± 1.48 ppm and c¯max = 13.03 ± 9.37 ppm in the personnel's breathing zone. Air pollution in the patient's room was approximately five times higher without a scavenging system. CONCLUSION: Ambient room pollution was minimal in most cases, and the measured values were within or below the recommended exposure limits. Caution should be taken during refilling of the MIRUS™ system, as this was accompanied by higher pollution levels. The combined use of air-conditioning and gas scavenging systems is strongly recommended.

Comparison of perioperative strategies in ICD patients: The perioperative ICD management study (PIM study).

BACKGROUND: The prevalence of patients with implanted cardioverter defibrillators (ICDs) and the frequency of surgery on these patients are steadily on the rise. Guidelines recommend preoperative ICD reprogramming, although this is sometimes difficult in clinical practice. Placing a magnet on the ICD is a practical alternative and even no inactivation is possible in selected cases. METHODS: In this prospective observational study, we compared different perioperative ICD management strategies depending on the location of the surgery and the type of electrocautery used. Patients undergoing surgery above the umbilicus with monopolar electrocautery had their ICD therapy inactivated by reprogramming. When surgery below the navel or surgery above the navel with bipolar electrocautery was completed, ICD inactivation was performed using a magnet. No inactivation was performed on patients undergoing lower extremity surgery with bipolar electrocautery. Only ICD patients who were not pacemaker dependent were enrolled. After surgery, the ICDs were assessed regarding documented arrhythmias and parameters. RESULTS: Out of 101 patients included in this study, the ICD was preoperatively reprogrammed in 42 patients (41.6%), a magnet was used on 45 patients (44.5%), and ICDs were not deactivated at all in 14 patients (13.9%). No intraoperative electromagnetic interference was detected. Postoperative ICD analysis demonstrated no changes of preset parameters. CONCLUSIONS: All three tested ICD management strategies were proved safe in this study. Keeping the location of surgery and the type of electrocautery in mind, an intraoperative magnet or even no ICD deactivation at all could be feasible alternatives in surgery on patients with ICDs.

Use of the MIRUS™ system for general anaesthesia during surgery: a comparison of isoflurane, sevoflurane and desflurane.

The MIRUS™ system enables automated end-expired control of volatile anaesthetics. The device is positioned between the Y-piece of the breathing system and the patient's airway. The system has been tested in vitro and to provide sedation in the ICU with end-expired concentrations up to 0.5 MAC. We describe its performance in a clinical setting with concentrations up to 1.0 MAC. In 63 ASA II-III patients undergoing elective hip or knee replacement surgery, the MIRUS™ was set to keep the end-expired desflurane, sevoflurane, or isoflurane concentration at 1 MAC while ventilating the patient with the PB-840 ICU ventilator. After 1 h, the ventilation mode was switched from controlled to support mode. Time to 0.5 and 1 MAC, agent usage, and emergence times, work of breathing, and feasibility were assessed. In 60 out of 63 patients 1.0 MAC could be reached and remained constant during surgery. Gas consumption was as follows: desflurane (41.7 ± 7.9 ml h-1), sevoflurane (24.3 ± 4.8 ml h-1) and isoflurane (11.2 ± 3.3 ml h-1). Extubation was faster after desflurane use (min:sec): desflurane 5:27 ± 1:59; sevoflurane 6:19 ± 2:56; and isoflurane 9:31 ± 6:04. The support mode was well tolerated. The MIRUS™ system reliable delivers 1.0 MAC of the modern inhaled agents, both during mechanical ventilation and spontaneous (assisted) breathing. Agent usage is highest with desflurane (highest MAC) but results in the fastest emergence. Trial registry number: Clinical Trials Registry, ref.: NCT0234509.

[Need of analgetics in children aged 2-12 years after tonsil surgery]. / Analgetikabedarf bei Kindern im Alter zwischen 2 und 12 Jahren nach Tonsillenoperationen.

OBJECTIVE: Tonsil surgery is one of the most painful operations in childhood. The Children's and Infants' Postoperative Pain Scale (CHIPPS), the Faces Pain Scale-Revised (FPS-R) and the little-known German version of the parents' postoperative pain measure (PPPM-D) are age-appropriate measures. Children undergoing intracapsular tonsillectomy (TO) or extracapsular tonsillectomy (TE) received the non-opioids ibuprofen (IBU) and paracetamol (PCM) on a "as needed"-basis requested by parents. A pain service checked pain scales and applied piritramide as rescue medication (RM) if required. Objective was evalution of sufficient analgesia. Endpoints were number of patients (PAT) needing the RM, doses of requested non-opioids, consistency of indications in different pain scales and correlation between pain and efficacy of the premedication or duration of the intervention. MATERIAL/METHODS: 3 measures were carried out daily: CHIPPS for PAT ≤ 4 years old, FPS-R from the age of 5. Parents completed the PPPM-D. Exceeding a cut-off score of 4 in CHIPPS or FPS-R or 6 in PPPM-D was rated as indication for RM. RESULTS: We included 68 PAT in an interim analysis. Mean daily doses of non-opioids within the first 3 postoperative days were as follows: PAT undergoing TE got 14,1-16,3 mg/Kg IBU and 4,2-12,4 mg/Kg PCM. PAT undergoing TO got 10,8-14,7 mg/Kg IBU and 5,2-8,8 mg/Kg PCM. On 212 visits PAT required RM, but 121 times it was detected in the PPPM-D only. After exclusion of potentially false-positive results remained 67 % PAT after TE and 48 % PAT after TO with at least 1 indication for RM. The study was terminated due to the high need for RM. CONCLUSIONS: The need of non-opioids was underrated. Combining the PPPM-D with established measures may improve the postoperative pain therapy.

The impact of the anesthetic conserving device on occupational exposure to isoflurane among intensive care healthcare professionals.

BACKGROUND: Use of anesthetic conserving devices (ACD) for inhalational isoflurane sedation in Intensive Care Units (ICU) has grown in recent years, and healthcare professionals are concerned about isoflurane pollution and exposure-related health risks. Real-time measurements to determine isoflurane exposure in ICU personnel during short-term patient care procedures and ACD handling have not yet been performed. METHODS: Isoflurane concentrations in the breathing zones of ICU staff (25 cm around the nose and mouth) were measured, by photoacoustic gas monitoring, during daily practice including tracheal suctioning, oral hygiene, body care, and patient positioning. Isoflurane pollution was further determined during ACD replacement, syringe filling, and after isoflurane spillages. RESULTS: The average mean isoflurane concentration 25 cm above patients' tracheostoma was 0.3 ppm. Mean (cmean) and maximum (cmax) isoflurane exposure in personnel's breathing zones during patient care ranged from 0.4 to 1.9 ppm and 0.7 to 6.6 ppm, respectively. Isoflurane exposure during ACD replacement was cmean 0.5 to 17.4 ppm and cmax 0.8 to 114.3 ppm. Isoflurane concentrations during ACD syringe filling ranged from 2.4 to 9.1 ppm. The maximum isoflurane concentrations after spillage were dose-dependent. CONCLUSIONS: Use of ACDs and patient physical manipulation are accompanied by isoflurane pollution. Baseline concentrations did not exceed long-term exposure limits, but short-term limits were occasionally exceeded during patient care procedures and ACD handling. Spillages should be avoided, especially when air-conditioning and scavenging systems are unavailable.

The child's behavior during inhalational induction and its impact on the anesthesiologist's sevoflurane exposure.

BACKGROUND: Sevoflurane is commonly used for inhalational inductions in children, but the personnel's exposure to it is potentially harmful. Guidance to reduce gas pollution refers mainly to technical aspects, but the impact of the child's behavior has not yet been studied. AIMS: The purpose of this study was to determine how child behavior, according to the Frankl Behavioral Scale, affects the amount of waste sevoflurane in anesthesiologists' breathing zones. METHODS: Sixty-eight children aged 36-96 months undergoing elective ENT surgery were recruited for this prospective, observational investigation. After oral midazolam premedication (0.5 mg/kg body weight), patients obtained sevoflurane using a facemask with an inspiratory concentration of 8 Vol.% in 100% oxygen (flow 10 L/min). Ventilation was manually supported and a venous catheter was placed. The inspiratory sevoflurane concentration was reduced, and remifentanil and propofol were administered before the facemask was removed and a cuffed tracheal tube inserted. The child's behavior toward the operating room personnel during induction was evaluated by the anesthesiologist (Frankl Behavioral Scale: 1-2 = negative behavior, 3-4 = positive behavior). During induction mean (c¯mean) and maximum (c¯max), sevoflurane concentrations were determined in the anesthesiologist's breathing zone by continuous photoacoustic gas monitoring. RESULTS: Mean and maximum sevoflurane concentrations were c¯mean = 4.38 ± 4.02 p.p.m and c¯max = 70.06 ± 61.08 p.p.m in patients with positive behaviors and sufficient premedications and c¯mean = 12.63 ± 8.66 p.p.m and c¯max = 242.86 ± 139.91 p.p.m in children with negative behaviors and insufficient premedications (c¯mean: P < .001; c¯max: P < .001). CONCLUSION: Negative behavior was accompanied by significantly higher mean and maximum sevoflurane concentrations in the anesthesiologist's breathing zone compared with children with positive attitudes. Consequently, the status of premedication influences the amount of sevoflurane pollution in the air of operating rooms.

Survival after long-term isoflurane sedation as opposed to intravenous sedation in critically ill surgical patients: Retrospective analysis.

BACKGROUND: Isoflurane has shown better control of intensive care sedation than propofol or midazolam and seems to be a useful alternative. However, its effect on survival remains unclear. OBJECTIVE: The objective of this study is to compare mortality after sedation with either isoflurane or propofol/midazolam. DESIGN: A retrospective analysis of data in a hospital database for a cohort of consecutive patients. SETTING: Sixteen-bed interdisciplinary surgical ICU of a German university hospital. PATIENTS: Consecutive cohort of 369 critically ill surgical patients defined within the database of the hospital information system. All patients were continuously ventilated and sedated for more than 96 h between 1 January 2005 and 31 December 2010. After excluding 169 patients (93 >79 years old, 10 <40 years old, 46 mixed sedation, 20 lost to follow-up), 200 patients were studied, 72 after isoflurane and 128 after propofol/midazolam. INTERVENTIONS: Sedation with isoflurane using the AnaConDa system compared with intravenous sedation with propofol or midazolam. MAIN OUTCOME MEASURES: Hospital mortality (primary) and 365-day mortality (secondary) were compared with the Kaplan-Meier analysis and a log-rank test. Adjusted odds ratios (ORs) [with 95% confidence interval (95% CI)] were calculated by logistic regression analyses to determine the risk of death after isoflurane sedation. RESULTS: After sedation with isoflurane, the in-hospital mortality and 365-day mortality were significantly lower than after propofol/midazolam sedation: 40 versus 63% (P = 0.005) and 50 versus 70% (P = 0.013), respectively. After adjustment for potential confounders (coronary heart disease, chronic obstructive pulmonary disease, acute renal failure, creatinine, age and Simplified Acute Physiology Score II), patients after isoflurane were at a lower risk of death during their hospital stay (OR 0.35; 95% CI 0.18 to 0.68, P = 0.002) and within the first 365 days (OR 0.41; 95% CI 0.21 to 0.81, P = 0.010). CONCLUSION: Compared with propofol/midazolam sedation, long-term sedation with isoflurane seems to be well tolerated in this group of critically ill patients after surgery.

Occupational Chronic Sevoflurane Exposure in the Everyday Reality of the Anesthesia Workplace.

BACKGROUND: Although sevoflurane is one of the most commonly used volatile anesthetics in clinical practice, anesthesiologists are hardly aware of their individual occupational chronic sevoflurane exposure. Therefore, we studied sevoflurane concentrations in the anesthesiologists' breathing zones, depending on the kind of induction for general anesthesia, the used airway device, and the type of airflow system in the operating room. Furthermore, sevoflurane baselines and typical peaks during general anesthesia were determined. METHODS: Measurements were performed with the LumaSense Photoacoustic Gas Monitor. As we detected the gas monitor's cross-sensitivity reactions between sevoflurane and disinfectants, regression lines for customarily used disinfectants during surgery (Cutasept®, Octeniderm®) and their alcoholic components were initially analyzed. Hospital sevoflurane concentrations were thereafter measured during elective surgery in 119 patients. The amount of inhaled sevoflurane by anesthesiologists was estimated according to mVA = cVA × V × t × ρVA aer. RESULTS: Induction of general anesthesia stopped after tracheal intubation with the patient's expiratory sevoflurane concentration of 1.5%. Thereby, inhalational inductions (INH) caused higher sevoflurane concentrations than IV inductions (mean [SD]: (Equation is included in full-text article.)[ppm] INH 2.43 ± 1.91 versus IV 0.62 ± 0.33, P < 0.001; mVA [mg] INH 1.95 ± 1.54 versus IV 0.30 ± 0.22, P < 0.001). The use of laryngeal mask airway (LMA™) led to generally higher sevoflurane concentrations in the anesthesiologists' breathing zones than tracheal tubes ((Equation is included in full-text article.)[ppm] tube 0.37 ± 0.16 versus LMA™ 0.79 ± 0.53, P = 0.009; (Equation is included in full-text article.)[ppm] tube 1.91 ± 0.91 versus LMA™ 2.91 ± 1.81, P = 0.057; mVA [mg] tube 1.47 ± 0.64 versus LMA™ 2.73 ± 1.81, P = 0.019). Sevoflurane concentrations were trended higher during surgery in operating rooms with turbulent flow (TF) air-conditioning systems compared with laminar flow (LF) air-conditioning systems ((Equation is included in full-text article.)[ppm] TF 0.29 ± 0.12 versus LF 0.13 ± 0.06, P = 0.012; mVA [mg/h] TF 1.16 ± 0.50 versus LF 0.51 ± 0.25, P = 0.007). CONCLUSIONS: Anesthesiologists are chronically exposed to trace concentrations of sevoflurane during work. Inhalational inductions, LMA™, and TF air-conditioning systems in particular are associated with higher sevoflurane exposure. However, the amount of inhaled sevoflurane per day was lower than expected, perhaps because concentrations in previous measurements could be overestimated (10%-15%) because of the cross-sensitivity reaction.