Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2013
Randomized Controlled TrialUltrasound-guided radial arterial cannulation: long axis/in-plane versus short axis/out-of-plane approaches?
Arterial cannulation with ultrasound (US) guidance increases the success rate and reduces complications. US-guided vascular access has two main approaches: long axis in-plane (LA-IP) and short axis out-of-plane (SA-OOP) approaches. The purpose of this study was to compare performance time and possible complications between two techniques. ⋯ Posterior wall damage during arterial cannulation were found in 30 patients with SA-OOP Group (56 %) and 11 patients with LA-IP Group (20 %), (p < 0.05). In our study, the use of LA-IP approach during US-guided radial artery cannulation has higher success rate at first insertion. We also found LA-IP approach results in shorter cannulation time and decreased the incidence of complications.
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J Clin Monit Comput · Jun 2013
Review Historical ArticleIs pulse oximetry an essential tool or just another distraction? The role of the pulse oximeter in modern anesthesia care.
Since the discovery of anesthetic agents, patient monitoring has been considered one of the core responsibilities of the anesthesiologist. As depicted in Robert Hinckley's famous painting, The First Operation with Ether, one observes William Thomas Green Morton carefully watching over his patient. Since its founding in 1905, 'Vigilance' has been the motto of the American Society of Anesthesiologists (ASA). ⋯ This article reviews the available evidence for pulse oximetry. Further, it discusses contemporary issues, events, and perceptions that may help to explain how and why pulse oximetry may have been adopted as a standard of care despite the lack of supportive. Lastly, it discusses less obvious benefits of pulse oximetry that may have further implications on the future of anesthesia care and perhaps even automated anesthesia.
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A new application of photoplethysmography (PPG) has emerged recently to provide the possibility of heart rate monitoring without a telemetric chest strap. The aim of this study was to determine if a new device could detect pulsation over a broad range of skin types, and what light wavelength would be most suitable for detecting the signals. A light emitting diode-based PPG system was used to detect changes in pulsatile blood flow on 23 apparently healthy individuals (11 male and 12 female, 20-59 years old) of varying skin types classified according to a questionnaire in combination with digital photographs with a skin type chart. Four different light wavelengths (470, 520, 630, and 880 nm) were tested. Normalized modulation level is calculated as the AC/DC component ratio and represents the change in flow over the underlying constant state of flow or perfusion. ⋯ We concluded that a PPG-based device can detect pulsation across all skin types and that a greater resolution was obtained using a green light wavelength at rest and a green or blue light wavelength during exercise.
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J Clin Monit Comput · Jun 2013
A system for portable sleep apnea diagnosis using an embedded data capturing module.
Sleep apnea (SA) is a very common disease with serious health consequences, yet is very under-diagnosed, partially because of the high cost and limited accessibility of in-laboratory polysomnography (PSG). The purpose of this work is to introduce a newly developed portable system for the diagnosis of SA at home that is both reliable and easy to use. The system includes personal devices for recording breath sounds and airflow during sleep and diagnostic algorithms to process the recorded data. The data capturing device consists of a wearable face frame with an embedded electronic module featuring a unidirectional microphone, a differential microphone preamplifier, a microcontroller with an onboard differential analogue to digital converter, and a microSD memory card. The device provides continuous data capturing for 8 h. Upon completion of the recording session, the memory card is returned to a location for acoustic analysis. We recruited 49 subjects who used the device independently at home, after which each subject answered a usability questionnaire. Random data samples were selected to measure the signal-to-noise ratio (SNR) as a gauge of hardware functionality. A subset of 11 subjects used the device on 2 different nights and their results were compared to examine diagnostic reproducibility. Independent of those, system's performance was evaluated against PSG in the lab environment in 32 subject. The overall success rate of applying the device in un-attended settings was 94 % and the overall rating for ease-of-use was 'excellent'. Signal examination showed excellent capturing of breath sounds with an average SNR of 31.7 dB. Nine of the 11 (82 %) subjects had equivalent results on both nights, which is consistent with reported inter-night variability. The system showed 96 % correlation with simultaneously performed in-lab PSG. ⋯ Our results suggest excellent usability and performance of this system and provide a strong rationale to further improve it and test its robustness in a larger study.
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J Clin Monit Comput · Jun 2013
Near real-time notification of gaps in cuff blood pressure recordings for improved patient monitoring.
Blood pressure monitoring during anesthesia is an American Society of Anesthesiology standard. However, the anesthesia provider sometimes fails to engage the patient monitor to make periodic (generally every 3-5 min) measurements of Non-Invasive Blood Pressure (NIBP), which can lead to extended periods (>5 min) when blood pressure is not monitored. We describe a system to automatically detect such gaps in NIBP measurement and notify clinicians in real-time to initiate measurement. ⋯ The maximum gap encountered before SAM was 64 min, while it was 27 min with SAM notification. Real-time notification using SAM is an effective way to reduce both the number of instances and the duration of inadvertent, extended (>15 min) gaps in blood pressure measurements in the operating room. However, the frequency of gaps <15 min could not be reduced using the current configuration of SAM.