Journal of clinical monitoring and computing
-
J Clin Monit Comput · Dec 2014
Randomized Controlled TrialForty-five degree wrist angulation is optimal for ultrasound guided long axis radial artery cannulation in patients over 60 years old: a randomized study.
Arterial cannulation is a common anaesthetic procedure that might be challenging and time-consuming in elderly patients. To establish an appropriate wrist joint position for arterial cannulation is crucial for ultrasound (US)-guided cannulation success. This study aimed to find out the optimal wrist joint angle for long axis in-plane (LA-IP) US-guided approach in radial artery cannulation in elderly patients. ⋯ Number of attempts and total success rate were similar among groups, whereas first attempt success rate was significantly increased in 45° group compared to other groups (p < 0.05). Mean arterial height of the first attempt successful group was statistically increased compared to the first attempt failed group (p < 0.001) and mean cannulation time and mean number of attempts were also negatively correlated with arterial height (p < 0.001; for all comparisons). The 45° wrist angle increment might be advantageous in US-guided LA-IP radial artery cannulation in elderly patients in view of cannulation time and first attempt success rate.
-
J Clin Monit Comput · Dec 2014
Clinical TrialAnalysis of plethysmographic waveform changes induced by beach chair positioning under general anesthesia.
During shoulder surgery, patients typically are placed in the beach chair position. In rare cases, this positioning has resulted in devastating outcomes of postoperative cerebral ischemia (Cullen and Kirby in APSF Newsl 22(2):25-27, 2007; Munis in APSF Newsl 22(4):82-83, 2008). This study presents a method to noninvasively and continuously hemodynamically monitor patients during beach chair positioning by using the photoplethysmograph signal recorded from a commercial pulse oximeter. ⋯ The PPG was more accurate at monitoring the change to beach chair position than blood pressure or heart rate. With vasoactive drugs, pulse-associated PPG oscillations decreased only with phenylephrine while respiration-associated oscillations did not change. Frequency domain analysis of the PPG signal may be a better tool than traditional noninvasive hemodynamic parameters at monitoring patients during beach chair position surgery.
-
J Clin Monit Comput · Dec 2014
Multicenter StudyMonitoring of intratidal lung mechanics: a Graphical User Interface for a model-based decision support system for PEEP-titration in mechanical ventilation.
In mechanical ventilation, a careful setting of the ventilation parameters in accordance with the current individual state of the lung is crucial to minimize ventilator induced lung injury. Positive end-expiratory pressure (PEEP) has to be set to prevent collapse of the alveoli, however at the same time overdistension should be avoided. Classic approaches of analyzing static respiratory system mechanics fail in particular if lung injury already prevails. ⋯ Visual inspections showed, that good and medium quality data could be reliably identified. The new GUI allows visualization of intratidal compliance-volume curves on a breath-by-breath basis. The automatic categorisation of curve shape into one of six shape-categories provides the rational decision-making model for PEEP-titration.
-
J Clin Monit Comput · Dec 2014
Automatic control of the NMB level in general anaesthesia with a switching total system mass control strategy.
This paper presents a model based switching control strategy to drive the neuromuscular blockade (NMB) level of patients undergoing general anesthesia to a predefined reference. A single-input single-output Wiener system with only two parameters is used to model the effect of two different muscle relaxants, atracurium and rocuronium, and a switching controller is designed based on a bank of total system mass control laws. Each of such laws is tuned for an individual model from a bank chosen to represent the behavior of the whole population. ⋯ The reference tracking improvement technique is able to produce a better reference tracking. Also, this technique showed a better performance than the (EKF). Based on these results, the switching control strategy with a bank of total system mass control laws proved to be robust enough to be used as an automatic control system for the NMB level.