Journal of clinical monitoring and computing
-
J Clin Monit Comput · Aug 2016
Frequency domain analysis of cerebral near infrared spectroscopy signals during application of an impedance threshold device in spontaneously ventilating volunteers.
Currently available near infrared spectroscopy (NIRS) devices are unable to discriminate between arterial and venous blood, a potential source of artifact. The purpose of this study was to test the hypothesis that oscillations in NIR signals at the respiratory and cardiac frequency could be attributed to venous and arterial blood, respectively, and thereby isolated. After written informed consent was obtained, a two-wavelength NIRS device was placed over the left frontal cortex in 20 volunteers. ⋯ There were no other significant differences between pulsatile and non-pulsatile algorithms in the estimation of StO2. In 64 % of cases, both the low (ventilator) and high (cardiac) frequency estimates of StO2 were either both larger or both smaller than non-pulsatile StO2, suggesting that they were interrogating the same vascular bed. Frequency domain analysis cannot reliably separate NIRS waveforms into arterial and venous components.
-
J Clin Monit Comput · Aug 2016
Evaluation of transcutaneous and end-tidal carbon dioxide levels during inhalation sedation in volunteers.
Measurement of end-tidal carbon dioxide (PETCO2) is useful because of its noninvasiveness, continuity, and response time when sudden changes in ventilation occur during inhalation sedation. We compared the accuracy of PETCO2 using a nasal mask and nasal cannula with the accuracy of transcutaneous carbon dioxide (TC-CO2) and determined which method is more useful during inhalation sedation in volunteers. We used a modified nasal mask (MNM) and modified nasal cannula (MNC) for measurement of PETCO2. ⋯ The difference between the TC-CO2 and PETCO2 ranged from 3 to 6 mmHg in the MNM and from 2 to 5 mmHg in the MNC. The difference between two variables against the TC-CO2 and the CO2 waveforms obtained by means of the two devices were within the clinically acceptable range. Our two devices can provide continuous monitoring of PETCO2 with a supply of N2O/O2 in patients undergoing inhalation sedation.
-
J Clin Monit Comput · Jun 2016
Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device.
Respiratory variations in the photoplethysmographic waveform amplitude predict fluid responsiveness under certain conditions. Processing of the photoplethysmographic signal may vary between different devices, and may affect respiratory amplitude variations calculated by the standard formula. The aim of the present analysis was to explore agreement between respiratory amplitude variations calculated using photoplethysmographic waveforms available from two different pulse oximeters. ⋯ Concordance rate with a fluid load was 91 %. Agreement between respiratory variations in the photoplethysmographic waveform amplitude calculated from the available signals output by two different pulse oximeters was poor, both evaluated by LMSO and Bland-Altman plot. Respiratory amplitude variations from the available signals output by these two pulse oximeters are not interchangeable.
-
J Clin Monit Comput · Jun 2016
Comment LetterPaper or plastic? Simulation based evaluation of two versions of a cognitive aid for managing pediatric peri-operative critical events by anesthesia trainees: evaluation of the society for pediatric anesthesia emergency checklist.
Cognitive aids (CA), including emergency manuals and checklists, are tools designed to assist users in prioritizing and performing complex tasks during time sensitive, high stress situations (Marshall in Anesth Analgesia 117(5):1162-1171, 2013; Marshall and Mehra in Anaesthesia 69(7):669-677, 2014). The society for pediatric anesthesia (SPA) has developed a series of emergency checklists tailored for use by pediatric perioperative teams that cover a wide range of intraoperative critical events (Shaffner et al. in Anesth Analgesia 117(4):960-979, 2013). In this study, we evaluated user preferences for a CA (SPA checklist) using two different presentation formats, paper and electronic, during management of simulated critical events. ⋯ In this study, anesthesia trainees had a favorable opinion of the content and perceived clinical relevance of both versions of the CA. In both quantitative and qualitative analysis, the paper version of the CA was preferred over the electronic version by participants. Despite overall favorable responses to the CA, a sizeable number of participants chose not to use either version the CA during the crisis.
-
J Clin Monit Comput · Jun 2016
Observational StudyMonitoring of cerebral blood flow autoregulation in adults undergoing sevoflurane anesthesia: a prospective cohort study of two age groups.
Autoregulation of blood flow is a key feature of the human cerebral vascular system to assure adequate oxygenation and metabolism of the brain under changing physiological conditions. The impact of advanced age and anesthesia on cerebral autoregulation remains unclear. The primary objective of this study was to determine the effect of sevoflurane anesthesia on cerebral autoregulation in two different age groups. ⋯ Our data suggests that the autoregulatory plateau is shortened in both young and older patients under sevoflurane anesthesia with approximately 1 MAC. Lower and upper limits of cerebral blood flow autoregulation, as well as the autoregulatory range, are not influenced by the age of anesthetized patients. Trial registration ClinicalTrials.gov (NCT00512200).