Journal of clinical monitoring and computing
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As the clinical advantages of vapor anesthesia (VA) for sedation of patients in ICU become more apparent, the ergonomics, economy and safety issues need to be better addressed. Here we describe the use of a new commercial digital in-line anesthetic vaporizer that can be attached to the inspiratory limb of a ventilator. If used with a simple, and easily assembled secondary circuit and anesthetic reflector, the circuit remains remote from the patient, the VA consumption approaches a physical minimum, VA level is controlled and monitored, and the tidal volume size is not limited.
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J Clin Monit Comput · Aug 2018
Uncontrolled delivery of liquid volatile anaesthetic when using the anaesthetic conserving device.
During patient sedation with liquid volatile anaesthetic, some problems may occur through a process called auto-pumping, defined as an expansion of bubbles inside the syringe, which can lead to uncontrolled anaesthetic delivery. The study examined how the temperature of liquid volatile anaesthetics (sevoflurane and isoflurane) and the presence of gas bubbles in the syringe affect the occurrence of auto-pumping when using the anaesthetic conserving device (ACD, AnaConDa™, Sedana Medical, Uppsala, Sweden). Four different circumstances for each volatile anaesthetic were tested with a bench study: volatile anaesthetic at room temperature or precooled with and without the presence of gas bubbles in the syringe. ⋯ Furthermore, when the heat source was removed, a substantial decline in anaesthetic agent values below the baseline was observed with both anaesthetics. The presence of gas bubbles in the syringe, especially when exposed to a heat source, may provoke auto-pumping with uncontrolled excessive anaesthetic delivery. If auto-pumping is suspected, the syringe pump must be stopped and the ACD removed from the breathing circuit at once.
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J Clin Monit Comput · Aug 2018
Effects of indigo carmine intravenous injection on oxygen reserve index (ORi™) measurement.
To retrospectively investigate the effects of indigo carmine intravenous injection on oxygen reserve index (ORi™) in 20 patients who underwent elective gynecologic surgery under general anesthesia. The study subjects were patients who underwent elective gynecologic surgery under general anesthesia between April 2016 and January 2017, and were administered a 5-ml intravenous injection of 0.4% indigo carmine for clinical purposes during surgery with ORi monitoring. Changes in ORi within 20 min after indigo carmine injection were observed. ⋯ The median lowest value of ORi was 0 (range 0-0.16) and the median time to reach the lowest value of ORi was 2 min (range 1-4 min) after injection. ORi values returned to pre-injection levels within 20 min in 13 of 19 patients, and the median time to return to pre-injection levels was 10 min (range 6-16 min) after injection. During ORi monitoring it is necessary to consider the rapid reduction in ORi after intravenous injection of indigo carmine.
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J Clin Monit Comput · Aug 2018
Observational StudyNon-invasive blood pressure monitoring with an oscillometric brachial cuff: impact of arrhythmia.
Arrhythmia-induced beat-to-beat variability of blood pressure (BP) is deemed to hinder the reliability of non-invasive oscillometric measurements (NIBP) but few data support this belief. We assessed the impact of arrhythmia on a NIBP device never tested for this purpose. We compared, in intensive care unit patients with and without arrhythmia, the agreement between three pairs of NIBP (Infinity™ Delta monitor, Dräger medical systems) and invasive readings. ⋯ The detection of hypotension (systolic invasive BP < 90 mmHg or mean invasive BP < 65 mmHg) or hypertension (systolic invasive BP > 140 mmHg) by NIBP was similar during arrhythmia and regular rhythm [areas under the receiver operating characteristic curves (AUCROC) of 0.88-0.92, p > 0.13]. The detection of a 10% increase in mean invasive BP after cardiovascular intervention was also associated with similar AUCROCs between the two groups. Provided that triplicates are averaged, the agreement between NIBP measured with the tested device and invasive measurements was not worse during arrhythmia than during regular rhythm.
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J Clin Monit Comput · Aug 2018
Randomized Controlled TrialDesflurane usage during anesthesia with and without N2O using FLOW-i Automatic Gas Control with three different wash-in speeds.
AGC® (Automatic Gas Control) is the FLOW-i's automated low flow tool (Maquet, Solna, Sweden) that target controls the inspired O2 (FIO2) and end-expired desflurane concentration (FAdes) while (by design) exponentially decreasing fresh gas flow (FGF) during wash-in to a maintenance default FGF of 300 mL min-1. It also offers a choice of wash-in speeds for the inhaled agents. We examined AGC performance and hypothesized that the use of lower wash-in speeds and N2O both reduce desflurane usage (Vdes). ⋯ AGC performance for O2 and desflurane targeting is excellent. After 1 h, the wash-in speeds tested are unlikely to affect desflurane usage. N2O usage decreases Vdes proportionally with its reduction in FAtdes.