Quantification of exhaled propofol is not feasible during single-lung ventilation using double-lumen tubes: A multicenter prospective observational trial

Background

Volatile propofol can be measured in exhaled air and correlates to plasma concentrations with a time delay. However, the effect of single-lung ventilation on exhaled propofol is unclear. Therefore, our goal was to evaluate exhaled propofol concentrations during single-lung compared to double-lung ventilation using double-lumen tubes.

Methods

In a first step, we quantified adhesion of volatile propofol to the inner surface of double-lumen tubes during double- and single-lumen ventilation in vitro. In a second step, we enrolled 30 patients scheduled for lung surgery in two study centers. Anesthesia was provided with propofol and remifentanil. We utilized left-sided double-lumen tubes to separately ventilate each lung. Exhaled propofol concentrations were measured at 1-min intervals and plasma for propofol analyses was sampled every 20 min. To eliminate the influence of dosing on volatile propofol concentration, exhalation rate was normalized to plasma concentration.

Results

In-vitro ventilation of double-lumen tubes resulted in increasing propofol concentrations at the distal end of the tube over time. In vitro clamping the bronchial lumen led to an even more pronounced increase (Δ AUC +62%) in propofol gas concentration over time. Normalized propofol exhalation during lung surgery was 31% higher during single-lung compared to double-lung ventilation.

Conclusion

During single-lung ventilation, propofol concentration in exhaled air, in contrast to our expectations, increased by approximately one third. However, this observation might not be affected by change in perfusion-ventilation during single-lung ventilation but rather arises from reduced propofol absorption on the inner surface area of the double-lumen tube. Thus, it is only possible to utilize exhaled propofol concentration to a limited extent during single-lung ventilation.

Registration of Clinical Trial

DRKS-ID DRKS00014788 ( www.drks.de ).     

Super selective intra-arterial cerebral infusion of modern chemotherapeutics after blood–brain barrier disruption: where are we now,and where we are going

Journal of Neuro-Oncology - Intra-arterial (IA) delivery of therapeutic agents across the blood-brain barrier (BBB) is an evolving strategy which enables the distribution of high concentration...     

Mental status evaluation in older adults with cancer: Development of the Mental Health Index-13

Objectives

The Mental Health Index (MHI) is widely used as a measure of mental health status, but has not been evaluated in the geriatric oncology population. This study evaluated the MHI-17 in a geriatric oncology population, to establish validity and scoring rules.

Feasibility and Acceptability of a 3-Day Group-Based Digital Storytelling Workshop among Caregivers of Allogeneic Hematopoietic Cell Transplantation Patients: A Mixed-Methods Approach

Family caregivers are essential partners for patients undergoing hematopoietic cell transplantation (HCT). The caregiving role is emotionally, physically, and financially demanding. Intervention efforts to provide relief for caregiver stress during HCT are highly warranted. Storytelling interventions are accruing evidence for efficacy in therapeutic contexts. The purpose of this study was to conduct a 3-full consecutive day digital storytelling (DST) workshop to build knowledge on caregivers’ lived experiences during HCT, to pilot test DST with a small group of HCT caregivers, and to demonstrate feasibility and acceptability using qualitative and quantitative measures. Six adult caregivers of allogeneic HCT recipients (mean age, 60.2 years) attended a 3-day DST program (66% female, 83% white). All successfully created their personal audiovisual digital story (2 to 3 minutes long) and completed a survey. All participants rated the DST workshop as highly acceptable and therapeutic (mean score 5, on a scale of 1 to 5). Group discussions and interviews with participants further demonstrated high satisfaction and acceptability of the workshop format, setting, process, and structure. The survey results showed decreases in anxiety and depression from before to after the DST workshop with all participants showing change in the expected direction. This study demonstrates the feasibility and acceptability of a 3-day DST workshop as a distress-relieving tool for HCT caregivers. Future research is needed to test the efficacy of DST relative to a control condition.     

Preparation of Light‐Responsive Aliphatic Polycarbonate via Versatile Polycondensation for Controlled Degradation

Starting from (2,2,5‐trimethyl‐1,3‐dioxan‐5‐yl)methanamine with light‐responsive 4,5‐dimethoxy‐2‐nitrobenzyl protecting groups, a variety of light‐responsive copolycarbonates (LrPCs) are synthesized by a general two‐step polycondensation using lithium acetylacetonate (LiAcac) as catalyst. UV/Vis, ¹H nuclear magnetic resonance (NMR), and size exclusion chromatography (SEC) confirm the rapid decomposition of these polymers in response to irradiation with UV light. Stable and monodisperse nanoparticles with hydrodynamic diameters of 100 nm, formulated from 25% LrPC and 75% poly(lactic‐co‐glycolic acid) (PLGA), undergo rapid disruption upon triggering with UV light, while standard PLGA nanoparticles remain stable. Moreover, differing from the ring‐opening polymerization (ROP) of trimethylene carbonate‐based monomers, direct polycondensation of 1,3‐propanediol‐based monomers with pendent functional groups and other diols will enable the introduction of various properties into the polycarbonate backbone, and expand the family of biodegradable synthetic polymers for potential biomedical applications.     

A descriptive study on retrieved non-threaded and threaded implant designs

Objectives: In the light microscope compare the amount of bone saucerization for non‐threaded cylindrical and threaded implant designs in retrieved samples from patients. Material and method: Consecutively received retrieved oral implants from 117 patients, whereof 85 non‐threaded cylindrical and 85 Brånemark implants, have been included in the study. For 75 non‐threaded cylindrical and 46 Brånemark implants was the entire implant length available for calculation. Undecalcified ground sections were investigated in the light microscope with calculation of percentage of implant length coronal to the first bone–implant contact and percentage of bone to implant contact. Results: Mean value for implant length coronal to first bone–implant contact was 65%, standard error of the mean (SEM) 3 (range 0–100%), for non‐threaded cylindrical implants and 43%, SEM 6 (range 0–100%) for Brånemark implants. Mean values of bone contact along the entire implant length was 23%, SEM 2 (range 0–65%), for the non‐threaded cylindrical implants and 33%, SEM 5 (range 0–93%) for the Brånemark implants. Conclusion: Within the limitations of this retrospective, retrieval study non‐threaded cylindrical implants demonstrated a greater bone saucerization when evaluated in the light microscope.     

Alveolar cavitational osteopathosis. Manifestations of an infectious process and its implication in the causation of chronic pain

A recently discovered oral disease process of infectious origin, characterized by nonradiographically detectable, hollow, pathologic, alveolar cavitational lesions of significant size, is described. This oral infectious disease process, termed alveolar cavitational osteopathosis, is causally implicated not only in the genesis of certain craniofacial pain syndromes, among them idiopathic trigeminal neuralgia and atypical facial pain, but also in chronic pain syndromes remote from the craniofacial region including the back, chest, arms, legs and cervical areas. A diagnostic process is presented which serves to define the locus of nonradiographically detectable alveolar cavitational osteopathosis and correlates a given pathological site to a given area of pain. Comprehensive schematics have been developed defining the pain pathways emanating from the oral cavity and their specific relationship to sites of perceived pain both in the craniofacial region and other areas of the body. The treatment modality described serves to induce bone growth within the cavitational lesions, resulting in the subsequent eradication of the cavity. The abolition of osteopathosis results in significant or total disappearance of pain symptomatology.