Journal of Clinical Monitoring and Computing最新文献

After blood sampling from an arterial catheter, the reinjection of the clearing fluid (a mixture of saline solution and blood) is proposed to limit blood loss. However, reinjecting clots may cause embolic complications. The primary objective was to assess fibrinogen consumption in the clearing fluid as an indicator of clot formation over time. Additionally, we searched for macroscopic clots, evaluated changes in prothrombin time, factors II and V. In this prospective observational pilot study, we enrolled adult patients in an intensive care unit with a radial artery catheter who required measurements of hemostasis parameters. We used a locally developed closed blood sampling system. Hemostasis parameters were measured in patients' pure blood (reference) and in the clearing fluid, at 2, 3, and 5 min after the complete filling of the reservoir. Thirty patients were included and 120 samples were analyzed. Fibrinogen levels decreased over time: median [interquartile range (IQR)] of 4.3 [IQR:3.1;5.9] as reference level, 3.6 [IQR:2.7;4.7] at 2 min (p < 0.001), 3.4 [IQR:2.1;4.3] at 3 min (p < 0.001) and 3.0 [IQR:1.7;4.1] g/L at 5 min (p < 0.001). No clot was macroscopically detected in any samples. An antiplatelet agent was administered in 11 (37%) patients. Unfractionated heparin anti-Xa activity was higher than 0.10 UI/ml in 17 (57%). Although no macroscopic clots were observed in the clearing fluid, its coagulation factors decreased over the 5 min following reservoir filling, indicating potential initiation of clot formation. Our findings stress the need for further studies assessing the safety of reinjecting clearing fluid as part of patient blood management.

Purpose: The capnodynamic method, End Expiratory Lung Volume CO₂ (EELV-CO₂), utilizes exhaled carbon dioxide analysis to estimate End-Expiratory Lung Volume (EELV) and has been validated in both normal lungs and lung injury models. Its performance under systemic hypoxia and variations in CO₂ elimination is not examined. This study aims to validate EELV-CO₂ against inert gas wash in/wash out (EELV- SF6, sulfur hexafluoride) in a porcine model of stable hemodynamic conditions followed by hypoxic pulmonary vasoconstriction and inhaled nitric oxide (iNO).

Methods: Ten mechanically ventilated piglets were exposed to a hypoxic gas mixture and selective pulmonary vasoconstriction. Inhalation of nitric oxide was used to reverse the pulmonary vasoconstriction. Paired recordings of EELV-CO₂ and EELV-SF6, were conducted to assess their agreement of absolute values.

Results: EELV-CO₂ showed a bias of + 5 ml kg^- 1 compared to EELV-SF6, upper limit of agreement of 11 ml kg^- 1 (95%CI: 9-13 ml kg^- 1), lower limit of agreement - 1 ml kg^- 1 (95%CI: -3- 0 ml kg^- 1), mean percentage error 34%. Agreement between EELV-CO₂ and EELV-SF6 was largely constant but was affected by progressing hypoxia and reached maximum limit of agreement after iNO exposure. Re-introduction of normoxemia then stabilized bias and limits of agreement to baseline levels.

Conclusion: EELV-CO₂ generates absolute values in parallel with EELV -SF6. Stressing EELV-CO₂ with hypoxic pulmonary vasoconstriction and iNO, transiently impairs the agreement which stabilizes once normoxemia is reestablished.

Cardiac output can be estimated non-invasively by electrical cardiometry with the ICON® monitor (Osypka Medical GmbH, Berlin, Germany). Conflicting results have been reported regarding the cardiac output measurement performance of electrical cardiometry. In this prospective method comparison study, we compared cardiac output measured using electrical cardiometry (EC-CO; test method) with cardiac output measured using intermittent pulmonary artery thermodilution (PATD-CO; reference method) in patients after coronary artery bypass graft (CABG) surgery. We calculated the mean of the differences with 95%-limits of agreement (95%-LOA) and their corresponding 95%-confidence intervals (95%-CI) using Bland-Altman analysis and calculated the percentage error. We also analyzed trending using four-quadrant plot analysis. We analyzed 157 paired cardiac output measurements of 41 patients. Mean ± standard deviation PATD-CO was 5.1 ± 1.3 L/min and mean EC-CO was 5.3 ± 1.3 L/min. The mean of the differences ± SD between PATD-CO and EC-CO was -0.2 (95%-CI -0.5 to 0.2) ± 1.2 L/min with a lower 95%-LOA of -2.6 (95%-CI -3.1 to -2.0) L/min and an upper 95%-LOA of 2.3 (95%-CI 1.6 to 2.9) L/min. The percentage error was 47% (95%-CI, 37 to 56%). The concordance rate for cardiac output changes was 48%. In this study, the agreement between EC-CO and PATD-CO was not clinically acceptable in patients after CABG surgery. The trending ability of EC-CO was poor.

Intracranial pressure (ICP), cerebral blood flow and volume are affected by craniospinal elasticity and cerebrospinal fluid dynamics, interacting in complex, nonlinear ways. Traumatic brain injury (TBI) may significantly alter this relationship. This retrospective study investigated the relationship between the vascular and parenchymal intracranial compartments by analysing two amplitudes: cerebral blood flow velocity (AmpCBFV) and ICP (AMP) during hypocapnia manoeuvre in TBI patients. Twenty-nine TBI patients hospitalised at Addenbrooke's Hospital, whose ICP and CBFV were monitored during mild hypocapnia, were included. A linear metric of the relationship was defined as a moving-window correlation (R) between AmpCBFV and AMP, named RAMP. Nonlinear metrics were based on the Joint Symbolical Analysis (JSA) algorithm, which transforms AmpCBFV and AMP into sequences of symbols ('words') using a binary scheme with word lengths of three. The mean AmpCBFV and AMP were not significantly correlated at baseline (r = - 0.10) or during hypocapnia (r = - 0.19). However, the RAMP index was significantly higher at baseline (0.64 ± 0.04) compared to hypocapnia (0.57 ± 0.04, p = 0.035). The relative frequency of symmetrical word types (JSA_sym) describing the AmpCBFV-AMP interaction decreased during hypocapnia (0.35 ± 0.30) compared to baseline (0.44 ± 0.030; p = 0.004). Our results indicate that while the grouped-averaged AmpCBFV and AMP were not significantly correlated, either at baseline or during hypocapnia, significant changes were observed when using RAMP and JSA indices. Further validation of these new parameters, which reflect the association between the vascular and parenchymal intracranial compartments, is needed in a larger cohort.

Purpose: This study aimed to investigate the ability of a novel wearable bioimpedance sensor to monitor changes in fluid balance induced by furosemide. Because iso-osmotic fluid loss is expected to primarily comprise fluid from the extracellular compartment it was hypothesized that isotonic hypovolemia would increase the extracellular resistance (R_E).

Methods: 27 healthy adults (20 women, 7 men; 35 ± 10 year.) were continuously monitored by the bioimpedance sensor following administration of furosemide. Body weight, blood pressure, heart rate, sensation of thirst and selected blood parameters were tested before furosemide administration (t0), one hour (t1) and two hours (t2) after furosemide administration, and one hour after intake of a sports drink containing carbohydrate and electrolytes (t3). Urine elimination was measured throughout the intervention, and the change in extracellular fluid volume was estimated using urine elimination and established equations.

Results: During hypovolemia body weight was reduced by 1.4 ± 0.2 kg (1.7 ± 0.4%). Total urine elimination during fluid loss was 1277 ± 190 mL. R_E increased significantly from t0 to t2 (13.6 ± 2.9%). A strong correlation was observed between the estimated change in extracellular fluid volume and the measured change in R_E during the isotonic fluid loss.

Conclusion: This study demonstrates that the wearable bioimpedance device tested is very sensitive to furosemide-induced changes in fluid volume in healthy volunteers in a controlled environment. Additional research is needed to evaluate the ability of the device to track fluid status in a clinical setting.

Trial registration: The study was registered at clinicaltrials.gov 29th of October 2021 (NCT05129358).

Although intraoperative electroencephalography (EEG) is not consensual among anesthesiologists, growing evidence supports its use to titrate anesthetic drugs, assess the level of arousal/consciousness, and detect ischemic cerebrovascular events; in addition, intraoperative EEG monitoring may decrease the incidence of postoperative neurocognitive disorders. Based on the known and potential benefits of intraoperative EEG monitoring, an educational program dedicated to staff anesthesiologists, residents of Anesthesiology and anesthesia technicians was started at Cleveland Clinic Abu Dhabi in May 2022 and completed in June 2022, aiming to have all patients undergoing general anesthesia with adequate brain monitoring and following international initiatives promoting perioperative brain health. All the surgical cases performed under General Anesthesia at 24 daily locations were prospectively inspected during 15 consecutive working days in March 2023. The use or absence of a processed EEG monitor was registered. Of 379 surgical cases distributed by 24 locations under General Anesthesia, 233 cases (61%) had processed EEG monitoring. The specialty with the highest use of EEG monitoring was Cardiothoracic Surgery, with 100% of cases, followed by interventional Cardiology (90%) and Vascular Surgery (75%). Otorhinolaryngology (29%), Gastrointestinal Endoscopy (25%), and Interventional Pulmonology (20%) were the areas with the lowest use of EEG monitoring. Of note, in the Neuroradiology suite, no processed EEG monitor was used in cases under General Anesthesia. We identified a reasonable use of EEG monitoring during general anesthesia, unfortunately not reaching our target of 100%. The educational and support program previously implemented within the Anesthesiology Institute needs to be continued and improved, including workshops, online discussions, and journal club sessions, to increase the use of EEG monitoring in underused areas.

Intraoperative hypotension is common and associated with organ injury. Hypotension can not only occur during surgery, but also thereafter. After surgery, most patients are treated in post-anesthesia care units (PACU). The incidence of PACU hypotension is largely unknown - presumably in part because arterial pressure is usually monitored intermittently in PACU patients. We therefore aimed to evaluate the incidence, duration, and severity of PACU hypotension in low-risk patients recovering from non-cardiac surgery. In this observational study, we performed blinded continuous non-invasive arterial pressure monitoring with finger-cuffs (ClearSight system; Edwards Lifesciences, Irvine, CA, USA) in 100 patients recovering from non-cardiac surgery in the PACU. We defined PACU hypotension as a mean arterial pressure (MAP) < 65 mmHg. Patients had continuous finger-cuff monitoring for a median (25th percentile, 75th percentile) of 64 (44 to 91) minutes. Only three patients (3%) had PACU hypotension for at least one consecutive minute. These three patients had 4, 4, and 2 cumulative minutes of PACU hypotension; areas under a MAP of 65 mmHg of 17, 9, and 9 mmHg x minute; and time-weighted averages MAP less than 65 mmHg of 0.5, 0.3, and 0.2 mmHg. The median volume of crystalloid fluid patients were given during PACU treatment was 200 (100 to 400) ml. None was given colloids or a vasopressor during PACU treatment. In low-risk patients recovering from non-cardiac surgery, the incidence of PACU hypotension was very low and the few episodes of PACU hypotension were short and of modest severity.

This study was designed to evaluate the effects on hand catalepsy on parasympathetic tone assessed using Analgesia/Nociception Index (ANI) and on subjective rating of absorption, dissociation, and time perception among healthy volunteers. This was a randomized controlled trial including participants to a medical hypnosis congress in France. Ninety volunteers were randomized in two arms, all receiving a fifteen-minute positive hypnotic trance, with or without hand catalepsy. The relative parasympathetic tone assessed by ANI (Analgesia/Nociception Index), heart rate and respiratory rate were recorded at different times of the study protocol. The actual duration of the hypnotic session, calculated from eye closing to eye opening, was also recorded. At the end of the hypnotic trance, participants subjectively rated their level of absorption and dissociation on a 0-10 scale. They were also asked to estimate the duration of the hypnotic session from eye closing to eye opening. In total, ninety subjects were included in the study. One subject was excluded because of deviation in the protocol standard, leaving eighty-nine subjects for analysis. Subject characteristics were similar between groups. There was a statistically different increase in ANI and decrease in both heart rate and respiratory rate over time with no difference with or without hand catalepsy. There was no statistically significant difference in absorption and dissociation subjective scales between groups. The median [Q1-Q3] actual duration of hypnotic sessions was similar between the catalepsy and the control groups (9 [8-10] min vs. 8 [7-10] min, respectively). However, subjects in the catalepsy group estimated a longer duration of the hypnotic session (12 [10-15] min) than in the control group (10 [5-10] min) with a mean ± SD overestimation of 3 ± 4 min (p < 0.001). Parasympathetic comfort increased during the hypnotic trance with no difference between groups. However, adding hand catalepsy to a pleasant hypnotic trance did not appear to increase feelings of absorption or dissociation but created time distortion on the longer side that could be useful in some clinical settings. Nevertheless, further study is still needed to determine more precisely the physiological and psychological effects on hand catalepsy during the hypnotic trance.

Purpose: The compensatory reserve metric (CRM) is a novel tool to predict cardiovascular decompensation during hemorrhage. The CRM is traditionally computed using waveforms obtained from photoplethysmographic volume-clamp (PPG_VC), yet invasive arterial pressures may be uniquely available. We aimed to examine the level of agreement of CRM values computed from invasive arterial-derived waveforms and values computed from PPG_VC-derived waveforms.

Methods: Sixty-nine participants underwent graded lower body negative pressure to simulate hemorrhage. Waveform measurements from a brachial arterial catheter and PPG_VC finger-cuff were collected. A PPG_VC brachial waveform was reconstructed from the PPG_VC finger waveform. Thereafter, CRM values were computed using a deep one-dimensional convolutional neural network for each of the following source waveforms; (1) invasive arterial, (2) PPG_VC brachial, and (3) PPG_VC finger. Bland-Altman analyses were used to determine the level of agreement between invasive arterial CRM values and PPG_VC CRM values, with results presented as the Mean Bias [95% Limits of Agreement].

Results: The mean bias between invasive arterial- and PPG_VC brachial CRM values at rest, an applied pressure of -45mmHg, and at tolerance was 6% [-17%, 29%], 1% [-28%, 30%], and 0% [-25%, 25%], respectively. Additionally, the mean bias between invasive arterial- and PPG_VC finger CRM values at rest, applied pressure of -45mmHg, and tolerance was 2% [-22%, 26%], 8% [-19%, 35%], and 5% [-15%, 25%], respectively.

Conclusion: There is generally good agreement between CRM values obtained from invasive arterial waveforms and values obtained from PPG_VC waveforms. Invasive arterial waveforms may serve as an alternative for computation of the CRM.