Assessing the precision of a semiinvasive, extended hemodynamic monitoring device for cardiac output estimation in critically ill: A prospective single-center study
Pedro David Wendel Garcia (Zürich | CH)
Assessment of cardiac output is an imperative for the optimal treatment of critically ill patients with cardiac impairment. Thermodilution by means of the pulmonary artery catheter (PAC) is since its design the gold standard for this purpose. Non-calibrated pulse contour analysis devices offer a cardiac output estimation by means of analysis of the standard arterial line and may be a less invasive alternative, especially intra-operatively [1, 2].
To assess the accuracy and precision of semi-invasive cardiac monitoring by means of the Pulsioflex device in a critically ill population comparing it to pulmonary artery catheter measurements.
Between 2016 and 2019, patients admitted to the medical ICU of the University Hospital Zurich, extendedly hemodynamically monitored by means of a PAC were prospectively included. Hemodynamic data simultaneously recorded by the PAC and the Pulsioflex device as well as routine clinical parameters over the course of 51 hours were collected.
The study population consisted of 35 patients (69% male, age of 66 [56 - 74] years). The SAPS II at admission was 49 [37 - 64], the SOFA was 9 [6 – 11], the Vasopressor Dependency Index was 0.55 [0.19 – 5.82] and 77% of the patients were mechanically ventilated. Median time between ICU admission and data collection was 41 [25 – 73] hours. 29% of the patients were admitted due to a cardiogenic shock, 25% due to other cardiac pathologies, 17% due to a severe respiratory failure and 14% due to a sepsis/ septic shock.
Bland Altman (BA) analysis of proAQT versus PAC measured cardiac index (CI), after autocalibration, was -0.87 ± 1.96 l/min/m2 with a precision error (PE) of 64.8%. After external calibration of the proAQT with a PAC measurement, BA characteristics were 0.1 ± 0.61 l/min/m2 with a of PE 19.4%. One hour after external calibration the PE increased to 40.5%, 12 hours later the PE was 48.7% and 24 hours later it was 86.9%. The Concordance Correlation Coefficient over 48 hours showed a correlation of 0.76 [0.57 – 0.80]. The precision was dependent on changes in vasopressor needs during the observation period.
In a general medical ICU population the Pulsioflex device fails to accurately and precisely reproduce the CI in comparison to the PAC. After external calibration, precision is maintained below 40% for less than one hour, thus yielding useful information only across very short interventions such as volume challenges.
PROtocolized Care to Reduce HYpotension after Spinal Anaesthesia (ProCRHYSA). A randomized, parallel group trial
Mathieu Favre (Genève | CH)
Spinal anaesthesia is a safe procedure commonly used for a wide-ranging of surgical applications. One of the most common issues is arterial hypotension. Among the non-invasive methods for predicting and identifying fluid-responsive patients in spontaneous breath, there are currently two tests. The Passive Leg Raising Test (PLRT) consists in raising passively the patient's legs to increase venous return and therefore cardiac output. Ultrasound o f Inferior Vena Cava (IVC) is another useful test that analyses IVC’s variability during spontaneous breathing activity, which has been proven to be inaccurate in spontaneous ventilated critically ill patients, but there are little data in spontaneously breathing non-critical patients. Aim of this trial is to determine whether these two methods are effective in guiding fluid therapy both to reduce the rate of hypotension and fluid overload in non-critical patients.
Methods: This was a prospective, controlled, randomized, three-arm, parallel-group trial of consecutive patients undergoing elective surgery under spinal anaesthesia, randomized into three parallel groups. Inclusion criteria were spontaneously breathing adult patients of both sex, ASA-risk class I to III, undergoing an elective intervention under spinal anaesthesia. Primary outcome was the hypotension rate after spinal anaesthesia following fluid optimization therapy guided by IVCUS and PLRT test compared to empirical fluid administration.
Results: 484 consecutive patients were recruited (35 were excluded) and then randomized. The primary outcome about the hypotension rate shows 68 cases (46%) in the control group, 46 cases (35%) in the echo group and 65 cases (44%) in the PLRT group. Comparison the hypotension rates between the echo group and the control group, there is a reduction of 9% (p = 0.154), while among the echo group and the PLRT group there is a reduction of 11% (p = 0.086). The average amount of fluids administered to the patient between arrival under anesthesia and the onset of anesthesia is 141 ml for the control group, 336 ml for the echocardiography group and 168 ml for the PLRT group (p < 0.001). Globally the total amount of fluids administered is 453 ml for the control group, 593 ml for the echo group and 511 ml for the PLRT group, with significantly greater administration in the echocardiography group (p 0.01498).
Conclusion: IVC ultrasound seems to be a valid and safe method to reduce the rate of hypotension before spinal anesthesia.
Can New Wearable Technology significantly increase the Efficacy Cardiopulmonary Resuscitation? A controlled, randomized trial testing
Samuele Ceruti (Genève | CH)
Contexte & Objectives: Cardiovascular accidents are the leading cause of death. A cardiopulmonary resuscitation (CPR) of quality has well shown that can reduce the mortality; despite this, survival rate has not changed significantly during last years. Aim of this study is to test a new wearable glove to provide lay people with instructions during out-of-hospital CPR.
Methods: After ethical committee approval, we performed a blinded, controlled trial on an electronic mannequin AmbuMan to test the performance of adult volunteers, non-healthcare professionals performing a simulated CPR both, without and with glove, following the glove instructions. The group without glove, also called “no-glove” is intended as control group. Each compression performed on theelectronic mannequin AmbuMan was recorded by a connected laptop computer, drawing a depth frequency curve over the time. Primary outcome was to compare the accuracy of the two simulated CPR sessions in terms of depth and frequency of chest compression performed by the same lay volunteers. Secondary outcome was to compare the decay of performance and percentage of time in which the candidate performed accurate CPR. The difference between the two groups in regard to change in chest compression depth over time due to fatigue, defined as decay were also analyzed.
Results: 571 chest compressions were included: 293 in control group, 278 in glove group. Mean depth of compression in the control group was 55.17 mm versus 52.11 mm in the glove-group (p = 0.000016). Compressions with an appropriate depth were not statistically different (81.9% vs 73.6%, p = 0.017). Mean frequency of compressions in the group with glove was 117.67 rpm vs 103.02 rpm in the control group (p < 0.00001). The percentage of compression cycles with an appropriate rate (> 100 rpm) was 92.4% in the group with the glove versus 71% in the control group, with an observed difference of 21.4% between the two groups, which was statistically significant (p < 0.0001). A mean reduction over time of compressions depth of 5.3 mm (SD 10.28) was observed in the control group versus a mean reduction of 0.83 mm in the group wearing the glove (SD 9.91), but this mean difference in the decay of compressions delivery was not statistically significant (p = 0.018).
Conclusion: The use of the glove was effective in reducing by more than 20% the inappropriateness of the frequency of chest compressions during CPR.
Respiratory mechanics can be measured during spontaneous breathing at the bedside : illustration of feasibility
Davy Cabrio (Lausanne | CH)
CONTEXT: End-inspiratory (EIP) and end-expiratory (EEP) pauses are commonly used during volume assist control to assess respiratory mechanics. They can also be used during assisted ventilation (AV) for muscle pressure assessment . It requires ventilators able to perform EIP and EEP during AV. Plateau pressure (Pplat) usually increases in AV during EIP due to “hidden” inspiratory effort . Pressure muscular index (PMI) is equal to Pplat minus the sum of total positive end-expiratory pressure (PEEPtot, measured during an EEP) and set pressure support (PS); it theoretically reflects patient’s effort without esophageal pressure (Pes) monitoring, which is the gold standard to assess inspiratory muscle pressure (Pmus, difference of Pes during EIP and maximal drop of Pes during inspiration) . We aimed to illustrate the feasibility of measuring PMI using a standard ICU ventilator at the bedside and study the correlation between Pmus and PMI.
METHOD: Measurements were recorded in two ICU patients. Pes was measured using an esophageal balloon-equipped nasogastric tubes placed for advanced monitoring (severe acute respiratory distress syndrome – ARDS) and for a study protocol (difficult weaning after COPD exacerbation). Recorded EIP, EEP and Pes were used for post-hoc analyses. Results reported as ranges for the ARDS patient and as median [IQR] for the COPD patient. Correlation between Pmus and PMI tested with Spearman correlation test.
RESULTS: For the ARDS patient, 4 out of 5 EIP and EEP recorded over a 1-week span could be analyzed (1 was disrupted by an esophageal spasm). Both Pplat and PEEPtot could otherwise be assessed. Ventilator mode was pressure support ventilation (PSV 9-12 cmH2O). Pplat ranged from 23.1 to 33.3 cmH2O, PEEPtot ranged from 9.1 - 12.2 cmH2O, Pmus ranged from 7.1 - 14.6 cmH2O and PMI ranged from 2 - 8.7 cmH2O. For the COPD patient, 5 EIP and EEP were recorded in a 3-hour span and analyzed. Pplat = 18 [16.8 - 18.7] cmH2O, PEEPtot = 5.3 [5.3 – 5.8] cmH2O, Pmus = 21.5 [20.5 - 28.6] cmH2O, PMI = 7.9 [7.1 - 11.3] cmH2O. For all the recordings, Spearman r coefficient between Pmus and PMI was 0.63 (p = 0.08).
CONCLUSION: Muscular effort can be assessed in AV using EIP and EEP using ICU ventilators. However, real-time bedside analysis is difficult. Even recordings can be disrupted by artifacts (esophageal spasms) or active expiration. There seem to be a correlation in our small sample between muscular pressure assessed without and with Pes.