Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2020
Observational StudyEstimation of respiratory rate using infrared video in an inpatient population: an observational study.
Respiratory rate (RR) is one of the most sensitive markers of a deteriorating patient. Despite this, there is significant inter-observer discrepancy when measured by clinical staff, and modalities used in clinical practice such as ECG bioimpedance are prone to error. This study utilized infrared thermography (IRT) to measure RR in a critically ill population in the Intensive Care Unit. ⋯ Correlation between counting and ECG-derived RR demonstrated significance only at > 19 bpm (r = 0.562, p = 0.029). Overall agreement between IRT-derived RR at distances of 0.4-0.6 m and gold standard counting was satisfactory, and outperformed ECG derived bioimpedance. Contactless IRT derived RR may be feasible as a routine monitoring modality in wards and subacute inpatient settings.
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J Clin Monit Comput · Dec 2020
Oesophageal balloon calibration during pressure support ventilation: a proof of concept study.
Oesophageal balloon calibration improves the oesophageal pressure (Pes) assessment during invasive controlled mechanical ventilation. The primary aim of the present investigation was to ascertain the feasibility of oesophageal balloon calibration during pressure support ventilation (PSV). Secondarily, the calibrated Pes (Pescal) was compared to uncalibrated one acquired at 4 ml-filling volume (PesV4), as per manufacturer recommendation. ⋯ Vbest was 1.9 ± 1.6 ml in VCV and 1.7 ± 1.6 ml in PSV (p = 0.5217). PesV4 was overestimated compared to Pescal at end-expiration and end-inspiration (p <0.0001 for all comparisons) in both VCV (13.4 ± 3.4 cmH2O and 15.4 ± 3 cmH2O vs. 8.5 ± 2.9 cmH2O and 11.4 ± 3 cmH2O) and PSV (14.7 ± 4.2 cmH2O and 17 ± 3.9 cmH2O vs. 8.9 ± 3.4 cmH2O and 12.4 ± 3.9 cmH2O). In PSV, oesophageal balloon calibration is feasible and allows to obtain a reliable Pes assessment compared to uncalibrated approach.
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J Clin Monit Comput · Dec 2020
A simplified 4-parameter model of volumetric capnograms improves calculations of airway dead space and slope of Phase III.
To evaluate a compact and easily interpretable 4-parameter model describing the shape of the volumetric capnogram, and the resulting estimates of anatomical dead space (VDAW) and Phase III (alveolar plateau) slope (SIII). Data from of 8 mildly-endotoxemic pre-acute respiratory distress syndrome sheep were fitted to the proposed 4-parameter model (4p) and a previously established 7-parameter model (7p). Root mean square error (RMSE) and Akaike information criterion (AIC), as well as VDAW and SIII derived from each model were compared. ⋯ Mean differences between VDAW (2.1 ± 0.04 ml) and SIII (0.047 ± 0.004 mmHg/ml) from 7 and 4p were significant (p < 0.001), but within the observed cycle-by-cycle variability. The proposed 4-parameter model of the volumetric capnogram improves data fitting and estimation of VDAW and SIII as compared to the 7-parameter model of reference. These advantages support the use of the 4-parameter model in future research and clinical applications.
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J Clin Monit Comput · Dec 2020
Right ventricular transverse displacement increases following cardiac surgery: possibly compensating loss in tricuspid annular plane systolic excursion (TAPSE).
Right Ventricular (RV) output mostly derives from longitudinal shortening in normal hearts. However, following even uncomplicated cardiac surgery with preserved RV function a significant and sustained decrease in longitudinal contraction has been observed. How the RV compensates and sustains output in this setting remains unsettled. ⋯ RV speckle tracking strain did not change significantly. Increased transverse displacement likely compensates for reduction in RV longitudinal contraction following cardiac surgery and maintains cardiac output. The sustained output from the right ventricle was not related to an increased contractility.
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J Clin Monit Comput · Dec 2020
Insights into postoperative respiration by using continuous wireless monitoring of respiratory rate on the postoperative ward: a cohort study.
Change of respiratory rate (RespR) is the most powerful predictor of clinical deterioration. Brady- (RespR ≤ 8) and tachypnea (RespR ≥ 31) are associated with serious adverse events. Simultaneously, RespR is the least accurately measured vital parameter. ⋯ However, in the present study we did not validate the measurements against a reference method. Rather, we attempted to demonstrate the feasibility of achieving continuous wireless measurement in patients on surgical postoperative wards. As the technology used is based on impedance pneumography, obstructive apnoea might have been missed, namely in those patients receiving opioids post-operatively.