Włodzimierz Płotek

Influence of Time of Day on Propofol Pharmacokinetics and Pharmacodynamics in Rabbits

This study evaluates the administration time-of-day effects on propofol pharmacokinetics and sedative response in rabbits. Nine rabbits were sedated with 5 mg/kg propofol at three local clock times: 10:00, 16:00, and 22:00 h. Each rabbit served as its own control by being given a single infusion at the three different times of day on three separate occasions. Ten arterial blood samples were collected during each clock-time experiment for propofol assay. A two-compartment model was used to describe propofol pharmacokinetics, and the pedal withdrawal reflex was used as the sedation pharmacodynamic response. The categorical data comprising the presence or absence of pedal withdrawal reflex was described by a logistic model. The typical volume of the central compartment equaled 7.67 L and depended on rabbit body weight. The elimination rate constant depended on drug administration time; it was lowest at 10:00 h, highest at 16:00 h, and intermediate at 22:00 h. Delay of the anesthetic effect, with respect to plasma concentrations, was described by the effect compartment, with the rate constant for the distribution to the effector compartment equal to 0.335 min−1. Drug concentration had a large effect on the probability of anesthesia. The degree of anesthesia was largest at 10:00 h, lowest at 16:00 h, and intermediate at 22:00 h. In summary, both the pharmacokinetics and pharmacodynamics of propofol in rabbits depended on administration time. The developed population approach may be used to assess chronopharmacokinetics and chronopharmacodynamics of medications in animals and humans. (Author correspondence: agnbienert@op.pl)

Evaluation of the Trail Making Test and interval timing as measures of cognition in healthy adults: comparisons by age, education, and gender.

Background Human cognitive functioning can be assessed using different methods of testing. Age, level of education, and gender may influence the results of cognitive tests. Material/Methods The well-known Trail Making Test (TMT), which is often used to measure the frontal lobe function, and the experimental test of Interval Timing (IT) were compared. The methods used in IT included reproduction of auditory and visual stimuli, with the subsequent production of the time intervals of 1-, 2-, 5-, and 7-seconds durations with no pattern. Subjects included 64 healthy adult volunteers aged 18–63 (33 women, 31 men). Comparisons were made based on age, education, and gender. Results TMT was performed quickly and was influenced by age, education, and gender. All reproduced visual and produced intervals were shortened and the reproduction of auditory stimuli was more complex. Age, education, and gender have more pronounced impact on the cognitive test than on the interval timing test. The reproduction of the short auditory stimuli was more accurate in comparison to other modalities used in the IT test. Conclusions The interval timing, when compared to the TMT, offers an interesting possibility of testing. Further studies are necessary to confirm the initial observation.

Emotional Processes in Patients Undergoing Coronary Artery Bypass Graft Surgeries with Extracorporeal Circulation in View of Selected Indicators of the Inflammatory Condition

Background The aim of this study was to describe positive and negative emotions in patients undergoing coronary artery bypass graft (CABG) surgeries with extracorporeal circulation and the correlations between emotions and basic indicators of the inflammatory condition: C-reactive protein (CRP) concentration, body temperature, and leukocyte count. Material/Methods Standardized tools were used to select 52 patients (aged 47–63 years, 6 women – 11.5% and 46 men – 88.5%) without dementia or depression. The Positive and Negative Affect Schedule (PANAS) was used to examine positive affect (PA) and negative affect (NA) and the State-Trait Anxiety Inventory (STAI X1 and X2) was used to examine the anxiety level. The patients underwent CABG surgery according to a common anesthesia protocol and for 5 consecutive days they were observed in the ward, where selected indicators of the inflammatory condition were monitored. Results A detailed description of the results of examinations of emotions was presented. The patients with low PA-trait level, high NA-trait level, and high anxiety-trait level (STAI X2) exhibited statistically significantly higher body temperatures than the other patients in the postoperative period. The patients with high NA-trait and anxiety-state levels (STAI X1) had statistically significantly lower CRP levels in the postoperative period than the patients with low NA-trait and anxiety-state levels (STAI X1). Conclusions Patients undergoing CABG operations express both positive and negative affects. The changes in the inflammatory markers are expressed mostly by CRP concentration. There exist relationships between the result of tests assessing emotions and the markers of the inflammatory condition.

Psychomotor Functions and Interval Timing in Patients Receiving Intravenous Anesthesia for Endoscopic Procedures: The Pilot Study

Introduction. The aim of this study was to evaluate two measures in a cognitive examination: psychomotor function and the perception of time (PT) in patients after intravenous anesthesia for endoscopic procedures. Material and Methods. We tested 23 anesthetized patients (Anesthesia Group, AG) and 17 not anesthetized patients (Control Group, CG). The Dufour Cross-Shaped Apparatus (DA) was used to assess quick reactions. Perception of time (PT) was measured for 1-, 2-, 5-, and 7-second intervals. The tests were performed before the anesthesia was administered and 1.5, 3, and 6 hours after the procedure was completed. Results. The intervals that were generated and the reproduced visual stimuli were shorter than the patterns. The reproduced 1- and 2-second auditory stimuli were longer than the patterns. The remaining reproduced auditory impulses were shorter than the patterns. Conclusions. In anesthetized patients, quick psychomotor reactions and the ability to time intervals are preserved 1.5 h and later after intravenous anesthesia for endoscopy.

Carbon dioxide as a potential danger to medical rescue teams at work – A case study

Medical rescue teams might be exposed to the risk of accidental poisoning while performing rescue procedures. Exposure to the risk of lethal carbon dioxide (CO2) concentrations is a rare situation. This case study describes rescuing a patient who suffered from sudden cardiac arrest due to accidental CO2 poisoning. The victim was finally evacuated and resuscitated, but the circumstances of the rescue operation point to the need to equip ambulances with carbon dioxide detectors and hermetic oxygen masks. Med Pr 2017;68(1):135-138.