Continuous Cardiac Output Monitoring Research Articles

New generation continuous cardiac output monitoring from carbon dioxide elimination

BackgroundThere is continuing interest among clinicians in the potential for advanced hemodynamic monitoring and “goal directed” intravenous fluid administration guided by minimally-invasive cardiac output measurement to reduce complication rates in high risk patients undergoing major surgery. However, the adoption of the available technologies has been limited, due to cost, complexity and reliability of measurements provided. We review progress in the development of new generation methods for continuous non-invasive monitoring of cardiac output from measurement of carbon dioxide elimination in ventilated patients using the Differential Fick method.Main textThe history and underlying theoretical basis are described, and its recent further development and implementation using modern generation anesthesia monitoring and delivery systems by two separate but parallel methods, termed “Capnotracking” and “Capnodynamics”. Both methods generate breath-by-breath hands-free cardiac output monitoring from changes in carbon dioxide elimination produced by automatic computerized modulation of respiratory rate delivered by an electronic ventilator. Extensive preclinical validation in animal models of hemodynamic instability, with implanted ultrasonic flow probes for gold standard reference measurements, shows this approach delivers reliable, continuous cardiac output measurement in real time. The accuracy and precision of measurement by the Capnodynamic method were maintained under a wide range of both hemodynamic and respiratory conditions, including inotropic stimulation, vasodilatation, hemorrhage, caval compression, alveolar lavage, changes in tidal volume and positive end-expiratory pressure, and hypercapnia, with only brief derangement observed in a model of lower body ischemia involving release of prolonged aortic occlusion by an intra-aortic balloon. Phase 2 testing of a Capnotracking system in patients undergoing cardiac surgery and liver transplantation has achieved a percentage error of agreement with thermodilution of +/− 38.7% across a wide range of hemodynamic states.ConclusionsProgress in development of these technologies suggest that a robust, automated and reliable method of non-invasive cardiac output monitoring from capnography is close at hand for use in major surgery and critical care. The great advantage of this approach is that it can be fully integrated into the anesthesia machine and ventilator, using components that are already standard in modern anesthesia and intensive care workstations, and should be virtually hands-free and automatic.

Progress in noninvasive assessment of fluid responsiveness

Fluid infusion is one of the most common therapeutic measures in clinical practice. With the development of medical technology, the assessment of fluid responsiveness before fluid infusion has become simpler and less invasive. The assessment of fluid responsiveness is based on three aspects: cardiopulmonary interaction, volume-loading test and endogenous volume-loading test. This article reviews the progress in the assessment of fluid responsiveness with the application of ultrasound and noninvasive continuous cardiac output monitoring, and the prospect of future improvement. Key words: Noninvasive; Ultrasound; Continuous cardiac output monitoring; Fluid responsiveness

Efficacy of Stroke Volume Variation, Cardiac Output and Cardiac Index as Predictors of Fluid Responsiveness using Minimally Invasive Vigileo Device in Intracranial Surgeries.

Introduction:Functional hemodynamic monitoring using dynamic parameters such as stroke volume variations (SVVs) based on pulse contour analysis is considered more accurate than central venous pressure and mean arterial pressure (MAP) in predicting fluid responsiveness. New device, i.e., Vigileo system, allows automatic and continuous monitoring of cardiac output (CO) based on pulse contour analysis and respiratory stroke volume.Aim:The study aims to test the above hypothesis using graded volume loading step (VLS) to assess the accuracy of SVV as a predictor of fluid responsiveness in patients undergoing intracranial surgery.Materials and Methods:After taking ethical committee approval and informed consent, 60 patients aged between 18 and 55 years belonging to the American Society of Anesthesiologists physical status Class I and II, of either sex, scheduled for brain surgery were included in the study. In this study, 5 min after intubation, with stable hemodynamics, patients received volume loading in successive steps (VLS) of 200 ml of lactated Ringer's solution until the stroke volume increased to <10%. Blood pressure (BP), heart rate (HR), stroke volume (SV), and SVV were measured before and after each VLS. Optimal preload augmentation required by each patient was measured by the number of VLS after which an increase in SV was <10%.Results:There was a significant decrease in the baseline BP and SV in responsive and nonresponsive groups for the first VLS, but there is no change in HR statistically. There was a significant change in SV after first VLS. Receiver operating characteristic analysis showed a larger area under the curve of 0.758 for SVV compared to other measured variables. The median number of VLS administered were 2 per patient equating to a mean ± SD requirement of 368 ± 176 ml of crystalloid per patient as the optimal preoperative infusion volume.Conclusion:SVV is a better predictor of preload responsiveness measured with third-generation Vigileo device when compared to BP and HR.

Efficacy of minimal invasive cardiac output and ScVO2 monitoring during controlled hypotension for double-jaw surgery

BackgroundControlled hypotension (CH) provides a better surgical environment and reduces operative time. However, there are some risks related to organ hypoperfusion. The EV1000/FloTrac system can provide continuous cardiac output monitoring without the insertion of pulmonary arterial catheter. The present study investigated the efficacy of this device in double jaw surgery under CH.MethodsWe retrospectively reviewed the medical records of patients who underwent double jaw surgery between 2010 and 2015. Patients were administered conventional general anesthesia with desflurane; CH was performed with remifentanil infusion and monitored with an invasive radial arterial pressure monitor or the EV1000/FloTrac system. We allocated the patients into two groups, namely an A-line group and an EV1000 group, according to the monitoring methods used, and the study variables were compared.ResultsEighty-five patients were reviewed. The A-line group reported a higher number of failed CH (P = 0.005). A significant correlation was found between preoperative hemoglobin and intraoperative packed red blood cell transfusion (r = 0.525; P < 0.001). In the EV1000 group, the mean arterial pressure (MAP) was significantly lower 2 h after CH (P = 0.014), and the cardiac index significantly decreased 1 h after CH (P = 0.001) and 2 h after CH (P = 0.007). Moreover, venous oxygen saturation (ScVO2) decreased significantly at both 1 h (P = 0.002) and 2 h after CH (P = 0.029); however, these values were within normal limits.ConclusionThe EV1000 group reported a lower failure rate of CH than the A-line group. However, EV1000/FloTrac monitoring did not present with any specific advantage over the conventional arterial line monitoring when CH was performed with the same protocol and same mean blood pressure. Preoperative anemia treatment will be helpful to decrease intraoperative transfusion. Furthermore, ScVO2 monitoring did not present with sufficient benefits over the risk and cost.

Non-invasive cardiac output measurement with electrical velocimetry in patients undergoing liver transplantation: comparison of an invasive method with pulmonary thermodilution

BackgroundThe goal of this study was to evaluate the accuracy and interchangeability between continuous cardiac output (CO) measured by electrical velocimetry (COEv) and continuous cardiac output obtained using the pulmonary thermodilution method (COPAC) during living donor liver transplantation (LDLT).MethodTwenty-three patients were enrolled in this prospective observational study. CO was recorded by both two methods and compared at nine specific time points. The data were analyzed using correlation coefficients, Bland-Altman analysis for the percentage errors, and the concordance rate for trend analysis using a four-quadrant plot.ResultsIn total, 207 paired datasets were recorded during LDLT. CO data were in the range of 2.8–12.7 L/min measured by PAC and 3.4–14.9 L/min derived from the EV machine. The correction coefficient between COPAC and COEv was 0.415 with p < 0.01. The 95% limitation agreement was − 5.9 to 3.4 L/min and the percentage error was 60%. The concordance rate was 56.5%.ConclusionsThe Aesculon™ monitor is not yet interchangeable with continuous thermodilution CO monitoring during LDLT.Trial registrationThe study was approved by the Institutional Review Board of Chang Gung Medical Foundation in Taiwan (registration number: 201600264B0).

Comparison of dexmedetomidine versus propofol on hemodynamics in surgical critically ill patients

BackgroundSedation with dexmedetomidine and propofol may cause hypotension or bradycardia. This study aimed to compare the effects of dexmedetomidine and propofol on hemodynamics and clinical outcomes in surgical intensive care unit (ICU) patients after major abdominal surgery. Materials and methodsEnrolled patients were randomly allocated to the dexmedetomidine or propofol group. Cardiac index was measured using a continuous noninvasive cardiac output monitor on the basis of chest bioreactance. Heart rate, blood pressure, opioid requirement, urine output, delirium incidence, ICU length of stay, and total hospital length of stay were compared between the two groups. The incidences of bradycardia, hypotension, and severe low cardiac index were compared. ResultsWe enrolled 60 patients. Heart rate and mean arterial pressure were significantly lower in the dexmedetomidine group than in the propofol group. Cardiac index did not differ significantly between the two groups (dexmedetomidine group 3.1 L/min/m2, [95% confidence interval {95% CI} 2.8-3.3] versus propofol group 3.2 L/min/m2 [95% CI 2.9-3.5], P = 0.578). The incidences of bradycardia, hypotension, and severe low cardiac index did not differ significantly between the two groups. ConclusionsCardiac index did not differ significantly between the dexmedetomidine and propofol groups in surgical ICU patients after major abdominal surgery.

Efficacy of PiCCO monitoring in guiding volume therapy in patients with sepsis complicated with acute kidney injury

Objective To evaluate the efficacy of pulse indicator continuous cardiac output (PiCCO) monitoring in guiding volume therapy in patients with sepsis complicated with acute kidney injury. Methods Eighty-five patients with sepsis complicated with acute kidney injury were divided into PiCCO group (n=37) and routine group (n=48) according to whether PiCCO monitoring was used to guide volume therapy.The hemodynamic parameters at 6 and 24 h after volume therapy, fluid volume, consumption of vasoactive drugs, renal function, fatality in intensive care unit and 28-day fatality were recorded. Results Compared with routine group, the volume of fluid for resuscitation at 24 h after volume therapy, and central venous pressure were significantly decreased (P<0.05), the time of continuous renal replacement therapy was shortened, the urine volume was increased, the blood creatinine level was decreased, and the fatality rate in intensive care unit and 28-day fatality rate were decreased in group PiCCO (P<0.05). Conclusion For the patients with sepsis complicated with acute kidney injury, PiCCO monitoring can reasonably guide volume therapy and is helpful in improving the prognosis. Key words: Cardiac output; Catheterization, Swan-Ganz; Monitoring, physiologic; Sepsis; Fluid therapy; Acute kidney injury

Issues of Immunological and Hemodynamic Monitoring Before and During Kidney Transplantation in Sensitized Heart Transplant Recipient

Previously transplanted highly sensitized patients experience problems with subsequent transplantation. It is also difficult to provide optimal hemodynamic conditions during successive kidney transplantation in heart transplant recipients. Patient and methodsWe present a case of a 56-year old patient with end-stage renal failure after heart transplantation performed 21 years ago and hemodialyzed using arteriovenous fistula. The patient had 69% panel-reactive antibodies, had been on the active waiting list since 2013, and presented 335 positive crossmatches with deceased donors. He also positively crossmatched with a potential living donor. Detailed examination of anti-HLA antibodies revealed the absence of IgG donor-specific antibodies and negative crossmatch with dithiothreitol-treated serum. The transplantation from his wife was performed with positive crossmatch after 4 plasma exchanges and thymoglobulin induction. Because sympathetic and parasympathetic denervation of the transplanted heart and the presence of arteriovenous fistula induced volume overload of the right heart, we used central venous pressure (CVP) and the PiCCO2 for postsurgical assessment of cardiac output. ResultsMonitoring, like CVP and other static exponents of preload obtained by PICCO (extravascular lung water, global end-diastolic volume index) as well as the dynamic parameters obtained by PiCCO2 (pulse pressure variation, stroke volume variation), was not sensitive enough to describe recipient volume status. The immediate graft function was observed, and after 11 months satisfactory estimated glomerular filtration rate is noted with the absence of donor-specific antibodies. ConclusionThe history of heart transplantation with existing arteriovenous fistula makes clinical tools such as continuous cardiac output monitoring and CVP parameter inadequate for describing the hemodynamic situation. The high level of panel-reactive antibodies and positive crossmatch possibly caused by IgM antibodies do not have to withdraw the recipient from kidney transplantation.

Responsiveness of Noninvasive Continuous Cardiac Output Monitoring During the Valsalva Maneuver.

To describe the baseline hemodynamic variables and response time of hemodynamic changes associated with the Valsalva maneuver using noninvasive continuous cardiac output monitoring (Nexfin). Hemodynamic monitoring provides an integral component of advanced clinical care and the ability to monitor response to treatment interventions. The emergence of noninvasive hemodynamic monitoring provides clinicians with an opportunity to monitor and assess patients rapidly with ease of implementation. However, the responsiveness of this method in tracking dynamic changes that occur has not been fully elucidated. A prospective observational study was conducted involving 44 healthy volunteers (age = 38 ±12 years). Participants performed a Valsalva maneuvers to illicit dynamic changes in blood pressure, cardiac output, cardiac index, systemic vascular resistance index (SVRI), and stroke volume. Changes in these hemodynamic parameters were monitored while performing repeated standardized Valsalva maneuvers. Baseline hemodynamic values were obtained in all 44 participants, and showed an interaction with age, accompanying a significant decline in cardiac index (r = -.66, p < .05) and stroke volume (r = -.68,p < .05), and an increase in SVRI (r = .67, p < .05) with increasing age. The Valsalva maneuver, performed in 20 participants, resulted in a change of 10% from baseline blood pressure and cardiac index, which was detected within 4.53 s (SD = 4.36) and 3.31 s (SD = 2.21), respectively. Noninvasive continuous cardiac monitoring demonstrated the ability to rapidly detect logical and predictable hemodynamic changes. These observations suggest that such Nexfin technology may have useful clinical applications.

Performance of a second generation pulmonary capnotracking system for continuous monitoring of cardiac output.

Technologies for minimally-invasive cardiac output measurement in patients during surgery remain little used in routine practice. We tested a redeveloped system based on CO2 elimination (VCO2) by the lungs for use in ventilated patients, which can be seamlessly integrated into a modern anesthesia/monitoring platform, and provides automated, continuous breath-by-breath cardiac output monitoring. A prototype measurement system was constructed to measure VCO2 and end-tidal CO2 concentration with each breath. A baseline measurement of non-shunt cardiac output was made during a brief oscillating change in ventilator rate, according to the differential CO2 Fick approach and repeated at 5-10min intervals. Continuous breath-by-breath monitoring of cardiac output was performed between these intervals from measurement of VCO2, using a derivation of the Fick equation applied to pulmonary CO2 elimination and cardiac output displayed in real time. Measurements were compared with simultaneous measurements by thermodilution in 50 patients undergoing cardiac surgery or liver transplantation. Overall mean bias [sd] for agreement in cardiac output measurement was - 0.3 [1.1] L/min, percentage error ± 38.7%, intraclass correlation coefficient = 0.91. Concordance in measurement of changes of at least 15% in cardiac output was 81.4%, with a mean angular bias of - 1.7°, and radial limits of agreement of ± 76.2° on polar plot analysis. The accuracy and precision compared favourably to other clinical techniques. The method is relatively seamless and automated and has potential for continuous, cardiac output monitoring in ventilated patients during anesthesia and critical care.

Noninvasive continuous blood pressure monitoring by the ClearSight system during robot-assisted laparoscopic radical prostatectomy.

Robot-assisted laparoscopic radical prostatectomy (RALRP) is commonly performed in the surgical treatment of prostate cancer. However, the steep Trendelenburg position (25) and pneumoperitoneum required for this procedure can sometimes cause hemodynamic changes. Although blood pressure is traditionally monitored invasively during RALRP, the ClearSight system (BMEYE, Amsterdam, The Netherlands) enables a totally noninvasive and simple continuous blood pressure and cardiac output monitoring based on finger arterial pressure pulse contour analysis. We therefore investigated whether noninvasive continuous arterial blood pressure measurements using the ClearSight system were comparable to those obtained invasively in patients undergoing RALRP. Ten patients scheduled for RALRP with American Society of Anesthesiologists physical status I-II were included in this study. At each of the seven defined time points, noninvasive and invasive blood pressure measurements were documented and compared in each patient using Bland-Altman analysis. Although the blood pressure measured with the ClearSight system correlated with that measured invasively, a large difference between the values obtained by the two devices was noted. The ClearSight system was unable to detect blood pressure accurately during RALRP, suggesting that blood pressure monitoring using this device alone is not feasible in this small patient population. J. Med. Invest. 65:69-73, February, 2018.

Robotic hysterectomy in Trendelenburg position in a severely anaemic JKa alloimmunised patient with impending high-output cardiac failure: An anaesthetic challenge.

Kidd blood group alloimmunisation, though extremely rare, may produce considerable morbidity, and even mortality. Severe anaemia and impending high-output cardiac failure requiring blood transfusion should be weighed against the risk of severe transfusion reactions even with fully cross-matched blood. Kidd antibodies are a common cause of delayed haemolytic transfusion reaction (DHTR) since they have a tendency remain undetectable in plasma. A low -grade DHTR (second hit) was grossly amplified by a second DHTR (third hit) superimposed on it in our patient leading to severe haemolysis with serum bilirubin reaching 68 mg%. Indirect antiglobulin test (indirect Coombs reaction) should ideally be performed in all patients (scheduled for major surgery requiring blood transfusion) who have experienced a previous pregnancy or blood transfusion. Non-invasive continuous haemoglobin monitoring and non-invasive cardiac output monitoring can prove invaluable tools in management.

The ultrasonic monitoring coupled with passive leg raising test for evaluation of fluid responsiveness in critical patients

Objective To explore the value of predicting fluid responsiveness using velocity time index variation (ΔVTI) and stroke volume variation (ΔSV) before and after passive leg raising (PLR) monitored by bedside temporary test equipment (TTE). Methods A cohort of 42 patients supported with mechanical ventilation in our hospital admitted from October 2014 to October 2015 were prospectively selected. The hemodynamic variables including heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), VTI, SV and other parameters were monitored before and after after undergoing PLR. Fluid resuscitation volume expansion test was carried out after stroke volume index (SVI) monitored by pulse indicator continuous cardiac output monitoring (PICCO). Patients were divided into fluid responsiveness positive group and fluid responsiveness negative group according to presence or absence of SVI ≥ 15% after fluid resuscitation volume expansion. Results Of 42 patients, 22 belonged to fluid responsiveness positive group, 20 got into fluid responsiveness negative group. There were no significant differences in basic clinical data between two groups. Before and after PLR, there were no distinct changes in HR and CVP(P>0.05), while MAP, VTI and SV increased significantly(P 0.05), but HR, CVP and VTI increased significantly(P<0.05) in fluid responsiveness negative group. The degrees of ΔVTI and ΔSV in fluid responsiveness positive group were much higher than those in fluid responsiveness negative group (P<0.05). According to SVI ≥ 15% monitored by PICCO after fluid resuscitation volume expansion test as a standard, the area under the ROC (AUC) of ΔVTI between pre-PLR and post-PLR was 0.75 (95%CI: 0.593-0.907, P<0.01), the sensitivity and specificity were 63.6% and 95% respectively using ΔVTI 15.6% as threshold value. The AUC of ΔSV was 0.844 (95%CI: 0.716-0.972, P<0.01), the sensitivity and specificity were 81.8% and 85.0% respectively using ΔSV 10.5% as threshold value. Conclusion ΔVTI and ΔSV monitored by TTE before and after PLR could be employed for predicting fluid responsiveness of critical patients under the status of spontaneous respiration.Their value for prediction of critical patients could be further improved by combined employment of these two indexes of variation. Key words: Transthoracic echocardiography; Fluid responsiveness; Passive leg raising

Maternal hemodynamics: a method to classify hypertensive disorders of pregnancy

The classification of hypertensive disorders of pregnancy is based on the time at the onset of hypertension, proteinuria, and other associated complications. Maternal hemodynamic interrogation in hypertensive disorders of pregnancy considers not only the peripheral blood pressure but also the entire cardiovascular system, and it might help to classify the different clinical phenotypes of this syndrome. This study aimed to examine cardiovascular parameters in a cohort of patients affected by hypertensive disorders of pregnancy according to the clinical phenotypes that prioritize fetoplacental characteristics and not the time at onset of hypertensive disorders of pregnancy. At the fetal-maternal medicine unit of Ziekenhuis Oost-Limburg (Genk, Belgium), maternal cardiovascular parameters were obtained through impedance cardiography using a noninvasive continuous cardiac output monitor with the patients placed in a standing position. The patients were classified as pregnant women with hypertensive disorders of pregnancy who delivered appropriate- and small-for-gestational-age fetuses. Normotensive pregnant women with an appropriate-for-gestational-age fetus at delivery were enrolled as the control group. The possible impact of obesity (body mass index ≥30 kg/m2) on maternal hemodynamics was reassessed in the same groups. Maternal age, parity, body mass index, and blood pressure were not significantly different between the hypertensive disorders of pregnancy/appropriate-for-gestational-age and hypertensive disorders of pregnancy/small-for-gestational-age groups. The mean uterine artery pulsatility index was significantly higher in the hypertensive disorders of pregnancy/small-for-gestational-age group. The cardiac output and cardiac index were significantly lower in the hypertensive disorders of pregnancy/small-for-gestational-age group (cardiac output 6.5 L/min, cardiac index 3.6) than in the hypertensive disorders of pregnancy/appropriate-for-gestational-age group (cardiac output 7.6 L/min, cardiac index 3.9) but not between the hypertensive disorders of pregnancy/appropriate-for-gestational-age and control groups (cardiac output 7.6 L/min, cardiac index 4.0). Total vascular resistance was significantly higherin the hypertensive disorders of pregnancy/small-for-gestational-age group than in the hypertensive disorders of pregnancy/appropriate-for-gestational-age group and the control group. All women with hypertensive disorders of pregnancy showed signs of central arterial dysfunction. The cardiovascular parameters were not influenced by gestational age at the onset of hypertensive disorders of pregnancy, and no difference was observed between the women with appropriate-for-gestational-age fetuses affected by preeclampsia or by gestational hypertension with appropriate-for-gestational-age fetuses. Women in the obese/hypertensive disorders of pregnancy/appropriate-for-gestational-age and obese/hypertensive disorders of pregnancy/small-for-gestational-age groups showed a significant increase in cardiac output, as well as significant changes in other parameters, compared with the nonobese/hypertensive disorders of pregnancy/appropriate-for-gestational-age and nonobese/hypertensive disorders of pregnancy/small-for-gestational-age groups. Significantly low cardiac output and high total vascular resistance characterized the women with hypertensive disorders of pregnancy associated with small for gestational age due to placental insufficiency, independent of the gestational age at the onset of hypertension. The cardiovascular parameters were not significantly different in the women with appropriate-for-gestational-age or small-for-gestational-age fetuses affected by preeclampsia or gestational hypertension. These findings support the view that maternal hemodynamics may be a candidate diagnostic tool to identify hypertensive disorders in pregnancies associated with small-for-gestational-age fetuses. This additional tool matches other reported evidence provided by uterine Doppler velocimetry, low vascular growth factors in the first trimester, and placental pathology. Obesity is associated with a significantly higher cardiac output and outweighs other determinants of hemodynamics in pregnancy; therefore, in future studies on hypertensive disorders, obesity should be studied as an additional disease and not simply as a demographic characteristic.

Risk factors for blood coagulation abnormality in patients undergoing off-pump coronary artery bypass grafting

Objective To screen the risk factors for blood coagulation abnormality in patients undergoing off-pump coronary artery bypass grafting(OPCABG). Methods A total of 140 patients undergoing elective OPCABG were included in this study, and combined intravenous-inhalational anesthesia was performed during operation.The patients were divided into normal group and abnormal group according to whether or not blood coagulation abnormality developed during operation and within 48 h after operation.The data such as gender, age, body mass index, American Society of Anesthesiologists physical status, the number of operation per year for surgeons, comorbidities (hypertension and diabetes mellitus), preoperative hematocrit (Hct), left ventricular ejection fraction, arterial oxygen pressure, liver function, operation time and requirement for intraoperative continuous cardiac output monitoring, positive end expiratory pressure, tranexamic acid, ulinastatin and hydroxyethyl starch, postoperative acidosis and hypothermia were recorded. Results Blood coagulation abnormality was found in 43 patients, and the incidence was 31%.The results of logistic regression analysis showed that the number of operation per year for surgeons<50, preoperative abnormal liver function, preoperative Hct<35%, surgery time≥240 min, no use of continuous cardiac output monitoring during operation and postoperative hypothermia were risk factors for blood coagulation abnormality in patients undergoing OPCABG. Conclusion The number of operation per year for surgeons<50, preoperative abnormal liver function, preoperative Hct <35%, operation time≥240 min, no use of continuous cardiac output monitoring during operation and postoperative hypothermia are risk factors for blood coagulation abnormality in patients undergoing OPCABG. Key words: Coronary artery bypass, off-pump; Blood coagulation, abnormal; Risk factors

Accuracy of different methods in predicting fluid responsiveness in septic patients: a comparison between ultrasound, PiCCO and traditional methods

Objective To compare the accuracy of ultrasound, pulse indicator continuous cardiac output monitoring (PiCCO) and traditional methods in predicting fluid responsiveness in septic patients. Methods Forty-six septic patients of both sexes, aged 18-72 yr, requiring mechanical ventilation treatment in the intensive care unit, were enrolled in the study.Venous blood samples were collected for determination of plasma B-type natriuretic peptide (BNP) concentrations by chemiluminescence assay, and central venous pressure (CVP) was recorded.Stroke volume variation (SVVTTE), distensibility index of inferior vena cava (dIVC) and velocity time integral changes of aortic blood flow (ΔVTI) were measured by ultrasound method.SVVPiCCO and global end-diastolic volume index (GEDVI) were measured by PiCCO method.The patients were divided into negative fluid responsiveness group and positive fluid responsiveness group according to the fluid responsiveness after volume expansion.The receiver operating characteristic curves of the parameters mentioned above in predicting fluid responsiveness were drawn.A consistency check for dIVC, ΔVTI and SVVPiCCO thresholds was conducted by using Kappa statistics.The agreement between SVVTTE and SVVPiCCO was analyzed by the Bland-Altman analysis. Results There were 24 patients in positive fluid responsiveness group and 22 patients in negative fluid responsiveness group.Compared with negative fluid responsiveness group, the plasma BNP concentration, CVP and GEDVI were significantly decreased, and SVVPiCCO, SVVTTE, dIVC and ΔVTI were increased before volume expansion in positive fluid responsiveness group (P<0.05). The area under the curve (95% confidence interval), sensitivity and specificity of the plasma BNP concentration were 0.894 (0.807-0.981), 81.8% and 79.2%, respectively, of CVP 0.859 (0.752-0.965), 81.8% and 79.2%, respectively, of GEDVI 0.772 (0.628-0.915), 72.7% and 75.0%, respectively, of SVVPiCCO 0.965 (0.922-1.008), 95.8% and 81.8%, respectively, of SVVTTE 0.940 (0.874-1.006), 91.7% and 86.4%, respectively, of dIVC 0.964 (0.920-1.008), 83.3% and 95.5%, respectively, and of ΔVTI 0.958 (0.909-1.008), 87.5% and 90.9%, respectively.The Kappa value for dIVC threshold and SVVPiCCO threshold was 0.826, and for ΔVTI threshold and SVVPiCCO threshold was 0.743 (P<0.01). The mean deviation of SVVTTE and SVVPiCCO was 0.209, 95% confidence interval (-2.967-3.385)%, and the limit of agreement (-2.46-2.62)%(P<0.05). Conclusion Ultrasound and PiCCO methods can accurately predict fluid responsiveness, have a good agreement and are superior to the traditional method in septic patients. Key words: Echocardiography; Monitoring, physiologic; Vascular capacitance; Sepsis

Effect of global end diastolic volume index guidance fluid resuscitation in elderly patients with septic shock

To evaluate the effect of global end diastolic volume index (GEDVI) on fluid resuscitation in elderly patients with septic shock. A prospective randomized controlled trial (RCT) was conducted. Septic shock patients over 65 years admitted to intensive care unit (ICU) of Shandong Province, Zibo Central Hospital from January 2013 to December 2015 were enrolled. The patients were randomly divided into control group and observation group, 20 cases in each group. In accordance with the guidelines for the treatment of septic shock, early goal-directed therapy (EGDT), rehydration in the control group was treated with the guide of central venous pressure (CVP); observation group was received pulse indicator continuous cardiac output (PiCCO) monitoring, and rehydration was treated according to the GEDVI and extravascular lung water index (EVLWI), i.e. GEDVI was maintained in 650-800 mL/m2, EVLWI was not obviously increased compared with the basic value and without the emphasis of CVP. Initial acute physiology and chronic health evaluation II (APACHE II) score, sequential organ failure score (SOFA), procalcitonin (PCT), mean arterial pressure (MAP), lactic acid (Lac) and oxygenation index (PaO2/FiO2); serial Lac, central venous to arterial carbon dioxide pressure (Pcv-aCO2), fluid balance, the amount of noradrenaline accumulation, PaO2/FiO2 after 6, 24 and 48 hours resuscitation; mechanical ventilation time, incidence of acute heart failure, ICU hospitalization time and 28-day mortality were recorded. There was no significant difference in gender, age, APACHE II score, SOFA score, primary disease, infection site and basal PCT, MAP, Lac, PaO2/FiO2 between the two groups. Compared with the control group, 6 hours Lac, Pcv-aCO2 recovery, positive fluid balance, noradrenaline accumulation and PaO2/FiO2 of the observation group showed no significant difference; positive fluid balance 24 hours in the recovery was significantly reduced (mL: 2 919.80±986.44 vs. 3 991.40±933.53), Pcv-aCO2 significantly decreased [mmHg (1 mmHg = 0.133 kPa): 5.55±1.43 vs. 7.10±2.38], PaO2/FiO2 significantly improved (mmHg: 194.80±28.57 vs. 177.65±23.46), and noradrenaline accumulation was increased significantly (mg: 40.99±20.69 vs. 27.31±19.34) with statistically significant difference (all P < 0.05); the blood level of Lac 48 hours in the recovery was significantly decreased (mmol/L: 1.16±0.89 vs. 1.85±1.01), Pcv-aCO2 (mmHg: 5.35±1.18 vs. 6.70±2.34), and PaO2/FiO2 (mmHg: 215.75±33.84 vs. 190.60±32.89) were further improved, the positive fluid balance was significantly reduced (mL: 3 141.55±1 245.69 vs. 4 533.85±1 416.67, all P < 0.05). Compared with the control group, mechanical ventilation time (days: 3.65±1.31 vs. 4.50±1.19), ICU hospitalization time (days: 5.80±1.67 vs. 7.15±2.30) was significantly shorter in the observation group (both P < 0.05), acute heart failure rate was decreased significantly (5.0% vs. 30.0%, P < 0.05), but the 28-day mortality showed no statistical significance (25.0% vs. 40.0%, P = 0.311). Compared to the conventional EGDT methods, fluid resuscitation under the guidance of GEDVI in elderly patients with septic shock with less liquid loading, can achieve better oxygenation and reduce heart failure, shorten the duration of mechanical ventilation and ICU stay, and play an important significant guidance for elderly patients' fluid resuscitation with septic shock.

Diagnostic Accuracy of Pulse Pressure Variation Compared to Thoracic Fluid Content in Mechanically Ventilated Patients after Cardiac Surgery

Background: In clinical area, assessment of body fluid and determination of the intravascular volume after major surgeries such as heart surgery is a significant challenge. The initial purpose of intravascular volume assessment in patients with hemodynamic instability is to determine whether they would benefit from fluid administration or not. Objectives: This study aims to compare pulse pressure variation (PPV) compared to thoracic fluid content in checking out and optimizing fluid volume in mechanically ventilated patients admitted to intensive care unit after cardiac surgery. Methods: In the present study a prospective descriptive-analytic design was used. Thirty mechanically ventilated patients admitted to intensive care units of Rajaie heart center, Tehran, Iran, were recruited in the current study after cardiac surgery based on inclusion criteria. Data collection tools included demographic and clinical data sheets. Hemodynamic parameters such as CVP and pulse pressure were recorded by bedside monitoring. Thoracic fluid content (TFC) was measured by non-invasive continuous cardiac output monitoring (NICCOMO) system. Data were analyzed in SPSS version 15, using statistical tests. Results: The mean values of CVP, before and five minutes after fluid administration were significantly different (10.10 ± 6.01 mmHg and 12.37 ± 6.34 mmHg, respectively, P = 0.015). The mean changes in arterial pulse pressure, before and five minutes after fluid administration were significantly different (16.94 ± 8.32 mmHg and 12.77 ± 4.02 mmHg, respectively, P = 0.005). PPV greater than 13% had sensitivity, specificity and positive predictive value of 40%, 71% and 75% respectively while CVP greater than 5 mmHg had sensitivity, specificity and positive predictive of 13%, 85% and 66% respectively compared with cardiac index as the gold standard for fluid responsiveness. These findings suggest a higher diagnostic power of PPV compared to CVP to assess fluid volume. Conclusions: It seems that in the mechanically ventilated patients after heart surgery, PPV dynamic index is preferred to CVP static index to evaluate and maintain fluid volume.

Application of pulse indicator continuous cardiac output monitoring in the fluid management of children with acute respiratory distress syndrome

Objective To explore the application value of pulse indicator continuous cardiac output (PiCCO) monitoring in the fluid management of children with acute respiratory distress syndrome(ARDS). Methods Thirty-two children with ARDS admitted to Pediatric Intensive Care Unit(PICU) of Zhengzhou Children′s Hospital, from April 2013 to April 2016, were divided into intervention group (15 cases) and control group (17 cases) by adopting random number table method.Fluid management of intervention group by PiCCO, control group by central venous pressure, the 2 groups′ oxygenation index (OI), acute lung injury score, mechanical ventilation time and 28 days mortality were statistically compared.The categorical data were analyzed by using SPSS 11.0 software, and the t test was used for the mea-surement data.The categorical data and mortality comparison were analyzed by adopting χ2 test.The difference was statistically significant at P<0.05. Results After 3 days of mechanical ventilation, the changes of OI in the intervention group were significantly higher than those in the control group [(175.0±43.7) mmHg vs.(143.0±42.8) mmHg(1 mmHg=0.133 kPa), t=2.090 0, P 0.05). Conclusions PiCCO monitoring and guidance in the fluid management of pediatric ARDS can improve oxygenation after 3 days, reduce mechanical ventilation time, but can not significantly reduce the 28-day mortality. Key words: Pulse indicator continuous cardiac output; Acute respiratory distress syndrome; Mortality; Extravascular lung water; Fluid management

Haemodynamic changes during labour: continuous minimally invasive monitoring in 20 healthy parturients

BackgroundThere are few studies on maternal haemodynamic changes during labour. None have used continuous cardiac output monitoring during all labour stages. In this observational study, we monitored haemodynamic variables continuously during the entire course of labour in healthy parturients. MethodsContinuous haemodynamic monitoring with the LiDCOplus technique was performed in 20 healthy parturients during spontaneous labour, vaginal delivery and for 15minutes postpartum. Cardiac output, stroke volume, heart rate, systemic vascular resistance, and systolic arterial pressure were measured longitudinally at baseline (periods between/without contractions) and during contractions in early and late stage 1, stage 2, during delivery, and postpartum, and were analysed with marginal linear models. ResultsTwenty parturients were included. In early stage 1, baseline cardiac output was 6.3L/min (95% CI 5.7 to 6.9). Baseline values were similar across both labour stages and postpartum for all haemodynamic variables. During stage 2 contractions, cardiac output decreased by 32%, stroke volume decreased by 44%, heart rate increased by 52%, systemic vascular resistance increased by 88%, and systolic arterial pressure increased by 36% compared to baseline. During stage 1 contractions, haemodynamic changes were less profound and less uniform than during stage 2. ConclusionProgression of labour had no major effect on haemodynamic baseline values. Haemodynamic stress during contractions was substantial in both labour stages, yet most pronounced during the second stage of labour. The absence of an increase in stroke volume and cardiac output postpartum questions the common belief in an immediate rise in cardiac output after delivery due to autotransfusion from the contracted uterus.