Intraoperative reduction of vasopressors using processed electroencephalographic monitoring in patients undergoing elective cardiac surgery: a randomized clinical trial.

Intraoperative vasopressor and fluid application are common strategies against hypotension. Use of processed electroencephalographic monitoring (pEEG) may reduce vasopressor application, a known risk factor for organ dysfunction, in elective cardiac surgery patients. Randomized single-centre clinical trial at Jena University Hospital. Adult patients operated on cardiopulmonary bypass or off-pump coronary artery bypass grafting were randomised to receive anesthesia with visible or blinded pEEG using Narcotrend™. In blinded-Narcotrend (NT) depth of anesthesia was extrapolated from clinical signs, hemodynamic response and anesthetic concentration, supplemented by target indices between 37 and 64 in the visible-NT group. Intraoperative norepinephrine requirement (primary endpoint), fluid balance, extubation time, delirium occurrence and adverse events were evaluated. Patients of the intent-to-treat population (visible-NT: n = 123, blinded-NT: n = 122) had similar patient and procedural characteristics. Adjusted for type of surgery intraoperative Norepinephrine application was significantly reduced in visible-NT (n = 120, robust mean of cumulative dose 4.71 µg/kg bodyweight) compared to blinded-NT patients (n = 119, 6.14 µg/kg bodyweight) (adjusted robust mean difference 1.71 (95% CI 0.33-3.10) µg/kg bodyweight). Although reduction in patients operated on cardiopulmonary bypass was higher the interaction was not significant in post-hoc subgroup analysis. Intraoperative fluid balance was similar among both groups and strata. Extubation time was non-significantly lower in visible than in blinded-NT group. Overall postoperative delirium risk was 16.4% without differences among the groups. Adverse events-sudden movement/coughing, perspiration or hypertension-occurred more often with visible-NT, while one blinded-NT patient experienced intraoperative awareness. Titration of depth of anesthesia in elective cardiac surgery patients using pEEG allows to reduce application of norepinephrine.

[Epistemology in the intensive care unit-what is the purpose of a definition? : Paradigm shift in sepsis research]. / Erkenntnistheorie auf der Intensivstation ­ Welchen Zweck erfüllt eine Definition? : Paradigmenwechsel in der Sepsisforschung.

The adoption of the new sepsis definition in early 2016 introduced a new paradigm for the clinical picture of sepsis. Up until now, sepsis was defined as a systemic inflammatory reaction (systemic inflammatory response syndrome, SIRS) to an infection. Based on a better understanding of the molecular mechanisms, the focus of the new definition is no longer the inflammatory response, but rather the tissue damage and impairment of organ function which this induces. The paradigm thus moves away from the infection and the systemic inflammatory response, and toward that which makes sepsis so dangerous in terms of both disease dynamics and outcome: organ failure due to a dysregulated host response to an infection. This change of perspective or paradigm enables patients with an increased risk of developing sepsis to be recognized and treated earlier in clinical routine, even outside of the intensive care unit. The new definition also promotes development of new treatment strategies with improved ability to treat sepsis causally.

Patent blue sentinel node mapping in cervical cancer patients may lead to decreased pulse oximeter readings and positive methaemoglobin results.

BACKGROUND AND OBJECTIVE: Patent blue (4-[(4-diethylaminophenyl)-(4-diethylazaniumylidencyclohexa-2,5-dienyliden) methyl]-6-hydroxy-3-sulfo-benzolsulfonate, sodium salt) is a contrast dye used for the intraoperative detection of the primary lymphatic nodes draining the area of tumour infiltration. The dye is known to interact with pulse oximeter readings. However, the degree of alteration seems to be moderate and predictable when patent blue is injected into the perimammilar region during breast surgery. METHODS: Here we report severe interference with the anaesthetic monitoring when patent blue was injected into the cervix prior to laparoscopy-assisted radical vaginal hysterectomy for cervical cancer. RESULTS: Injection of patent blue into the cervix induced a rapid (within 14 +/- 9 min after the injection) and severe (from 98% to 89 +/- 2%) decrease in pulse oximeter readings, accompanied by positive methaemoglobin values of 7.3 +/- 2.5% (arterial co-oximetry, Bayer Rapidlab 865 blood gas analyser; Bayer, Fernwald, Germany). Control of these values by a different device (Radiometer ABL co-oximeter blood gas analyser; Radiometer, Willich, Germany) yielded negative methaemoglobin results (<1.7%, mean 0.9 +/- 0.6%). The arterial PO2 was normal in all patients throughout the procedure. CONCLUSION: Injection of patent blue into the cervix uteri interferes dramatically with pulse oximeter readings. This situation is further complicated by device-dependent arterial co-oximetry methaemoglobin results. For the time being it is recommendable to monitor adequate oxygenation of the patient in the presence of patent blue by regular control of the arterial PO2. Clearly, the unresolved issue of reliable methaemoglobin determination in the presence of patent blue remains a matter of clinical concern for anaesthetists.