The Edwards Acumen IQ system using peripheral arterial catheter-based waveforms to estimate cardiac output is not accurate as compared to thermodilution in dogs.

OBJECTIVE: To assess the agreement between cardiac output (CO) estimated via evaluation of the arterial pressure waveform by a novel monitoring system (Edwards Acumen IQ sensor and HemoSphere Advanced Monitor Platform [HS-IQ]; Edwards LifeSciences) and measured by thermodilution (TD) in anesthetized, normovolemic, and hypovolemic dogs. To assess the agreement between the HS-IQ CO measurements in the radial artery and dorsal metatarsal artery. ANIMALS: 8 purpose-bred Beagles. METHODS: Dogs were placed under general anesthesia. CO was measured via TD and via the HS-IQ at radial and dorsal metatarsal arterial catheters. CO measurements were obtained at 4 time points including normovolemic and multiple hypovolemic states. Paired measurements of CO were evaluated via the method of Bland and Altman with acceptable limits of agreement (LOA) defined as < 30%. RESULTS: A total of 24 (dorsal metatarsal) and 21 (radial) paired measurements were collected in 8 dogs. The overall bias (CI) for comparison of TD to radial arterial HS-IQ CO measurements was -0.09 L/min. LOA and proportional LOA were -2.66 to 2.49 L/min and -140.72% to 104.94%. The overall bias (CI) for comparison of TD to dorsal metatarsal arterial HS-IQ CO measurements was -0.26 L/min. LOA and proportional LOA were -2.76 to 2.24 L/min and -135.96% to 93.25%. The overall proportional error for radial arterial was -17.9% and for dorsal metatarsal was -21.4%. CLINICAL RELEVANCE: CO measurements with the HS-IQ were easy to obtain but did not produce results within a clinically acceptable range for either measurement site, with a very wide LOA. The CO estimations from the HS-IQ are not appropriate for clinical use at this time.

Agreement of cardiac output measurements by esophageal Doppler and transesophageal echocardiography with intermittent pulmonary artery thermodilution during pharmacologic manipulation of hemodynamics in anesthetized dogs.

OBJECTIVE: To compare cardiac output (CO) measurements by transesophageal echocardiography (TEECO) and esophageal Doppler monitor (EDMCO) with pulmonary artery thermodilution (PATDCO) in anesthetized dogs subjected to pharmacological interventions. The effect of treatments on EDM-derived indexes was also investigated. ANIMALS: 6 healthy male dogs (10.8 ± 0.7 kg). METHODS: Dogs were anesthetized with propofol and isoflurane, mechanically ventilated, and monitored with invasive mean arterial pressure (MAP), end-tidal isoflurane concentration (ETISO), PATDCO, TEECO, EDMCO, and EDM-derived indexes. Four treatments were administered to all dogs by randomization. Baseline data were collected before each treatment: (1) dobutamine infusion; (2) esmolol infusion; (3) phenylephrine infusion; and (4) ETISO > 3%. Data were collected after 10-minute stabilization and after 30 minutes of washout between treatments. Statistical tests were pairwise t test, Bland-Altman analysis, Lin's concordance correlation (ρc), and polar plot analysis with P < .05 set as significance. RESULTS: The mean ± SD relative bias (limits of agreement) for TEECO was 0.35 ± 25.2% (-49.1% to 49.8%) and for EDMCO was -27.2 ± 22.5% (-71.4% to 17%) versus PATDCO. The percent error for TEECO and EDMCO was 27.6% and 44.1%, respectively. The ρc value was 0.82 for TEECO and 0.66 for EDMCO. TEECO and EDMCO showed good trending ability. EDM-derived indexes displayed significant changes specific to the drug administered (P < .001). CLINICAL RELEVANCE: For minimally invasive CO monitoring, TEE may provide more favorable performance than EDM in clinical settings; however, EDM-derived indexes yield valuable hemodynamic information that reliably follows trends in CO, thus supporting critical decision-making in canine patients.

Evaluation of transpulmonary ultrasound dilution cardiac output in piglets: accuracy, precision and trending ability with room temperature injectate.

OBJECTIVE: Transpulmonary ultrasound dilution (TPUD) is a minimally invasive technique to measure cardiac output (CO) using a 1 mL kg-1 isotonic 37 °C saline injectate indicator. The objective was to evaluate the performance of TPUD using a room temperature saline injectate. STUDY DESIGN: Prospective experimental trial. ANIMALS: A total of seven anesthetized male Yorkshire piglets. METHODS: Piglets aged 1 month and weighing 7.7-9.0 kg were anesthetized with detomidine-ketamine-hydromorphone-isoflurane and a pulmonary artery flow probe (PAFP) placed via a median sternotomy. The thoracic cavity remained open during measurement of CO by PAFP and TPUD. The TPUD indicators of 1 mL kg-1 0.9% saline at 37 °C and 20 °C were compared during infusions of phenylephrine and dobutamine, blood withdrawal and replacement. Bias, limits of agreement (LoAs) and percentage error (PE) between each iteration of PAFP and TPUD were measured with Bland-Altman plots. Trending ability via concordance, angular bias and radial LoA were compared. RESULTS: Bland-Altman plots showed negligible bias with varying LoAs. PEs of 22% and 38% were found for 37 °C and 20 °C saline injectates, respectively. In the four-quadrant plots, the concordance rate was 94% and 100% for measurements obtained with 37 °C and 20 °C saline injectates, respectively. Angular bias for both were < ±5 °, with radial LoA < ±7 °. CONCLUSIONS: TPUD was accurate when using 1 mL kg-1 of isotonic saline at 37 °C in a range of CO within 0.2-0.8 L minute-1, and it reliably tracked positive and negative changes in CO. Room temperature (20 °C) indicator was less accurate but equally able to track direction of changes in CO. CLINICAL RELEVANCE: The use of room temperature injectates allows an easy, readily available clinical application of TPUD CO monitoring while preserving the trending ability of the monitor.

Transpulmonary ultrasound dilution is an acceptable technique for cardiac output measurement in anesthetized pigs.

OBJECTIVE: To evaluate cardiac output (CO) measurements using transpulmonary ultrasound (TPUD) technology and compare results with those of the gold standard, pulmonary arterial catheter thermodilution (PACTD), in 6 healthy anesthetized pigs during acute hemodynamic changes caused by manipulation of the blood volume. ANIMALS: 6 healthy male Landrace pigs. PROCEDURES: Over a period of 1 week, pigs were anesthetized with isoflurane, mechanically ventilated, and underwent instrumentation in dorsal recumbency. They were subjected to sequential experimental states during which the blood volume was manipulated so that the animals transitioned from normovolemia to hypovolemia (20% and 40% of blood volume depletion), back to normovolemia (autologous blood transfusion), and then to hypervolemia (following colloid bolus). During each volume state, CO measurements were compared between TPUD and PACTD. RESULTS: The mean ± SD relative bias between TPUD and PACTD was 7.71% ± 21.2% with limits of agreement -33.9% to 49.3%, indicating TPUD slightly underestimated CO values, compared with values obtained with PACTD. The mean ± SD of the bias between the 2 methods was 0.13 ± 0.5 L/min. Only 5 of 36 (13.9%) TPUD CO measurements had an absolute value of relative bias > 30%. The percentage error calculated for TPUD was 29.4%. CLINICAL RELEVANCE: Results suggested that TPUD measurements have acceptable agreement with PACTD measurements. Moreover, TPUD exhibits promising potential in being used interchangeably with PACTD for future hemodynamic research involving swine as species of interest.

Lithium dilution cardiac output measurements in isoflurane-anaesthetised goats: Jugular versus cephalic lithium chloride administration.

The administration of lithium chloride (LiCl) for cardiac output (CO) measurement via a peripheral instead of a central vein has been described previously as a valid alternative route in pigs and dogs. The aim of the study was to compare CO measurements after administration of LiCl using two peripheral veins, cephalic or jugular, in goats. Ten adult, female, experimental goats undergoing bilateral stifle arthrotomy were recruited for the study. Paired CO measurements were taken two minutes apart during stable conditions in isoflurane-anaesthetised goats. Forty-two paired CO measurements were taken in total, and the median (range) of paired CO measurement per goat were 4.5 (3-6). The mean (SD) CO using the cephalic and jugular vein for injection of LiCl was 5.28 (1.29) L min-1 and 5.20 (1.24) L min-1 respectively. The Bland-Altman analysis showed an acceptable agreement with a mean bias of 1.33% with limits of agreement (LoA) of -18.43 to 21.09%. The percentage of error was 25%. The four-quadrant plot analysis showed a poor agreement (71%) between the two routes. The polar plot showed a poor trending ability. An 86% inclusion rate (18/21 points) was reached with a ± 35° radial sector size. The findings revealed that the agreement between the two routes is not as precise as the authors expected, however the results are comparable with studies published previously.

Effect of thermodilution injectate volume and temperature on the accuracy and precision of cardiac output measurements for healthy anesthetized horses.

OBJECTIVE: To compare the accuracy and precision of cardiac output (CO) measurements derived from 4 thermodilution protocols that used different injectate temperatures and volumes in healthy adult horses. ANIMALS: 8 healthy adult horses. PROCEDURES: Horses were anesthetized and instrumented with Swan-Ganz catheters. The CO was derived from each of 4 thermodilution protocols (IV injection of physiologic saline [0.9% NaCl] solution chilled to < 5 °C at volumes of 1 mL/15 kg of body weight [protocol A; control], 1 mL/25 kg [protocol B], and 1 mL/35 kg [protocol C] or maintained at 17 °C at a volume of 1 mL/15 kg [protocol D]) 3 times during each of 5 measurement cycles, with a 30-minute interval between cycles. During each measurement cycle, protocol A was performed first, and protocols B, C, and D were performed in a randomized order. Mean CO and within-subject variance in CO were compared among the 4 protocols. RESULTS: Mean CO did not differ significantly among the 4 protocols. The within-subject variance for CO measurements derived from protocols C and D, but not protocol B, was significantly greater than that for protocol A (control). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that, in healthy adult horses, decreasing the thermodilution injectate volume to 1 mL/25 kg from the recommended volume of 1 mL/15 kg did not adversely affect the accuracy or precision of CO measurements. However, use of smaller injectate volumes or use of injectate at approximately room temperature is not recommended owing to a clinically unacceptable increase in CO measurement variability.

Evaluation of the ability of haemodynamic variables obtained with minimally invasive techniques to assess fluid responsiveness in endotoxaemic Beagles.

OBJECTIVE: To examine the ability of different haemodynamic variables recorded by minimally invasive monitoring techniques to assess fluid responsiveness (FR) in endotoxaemic Beagles. STUDY DESIGN: Prospective terminal experimental study. ANIMALS: A group of six healthy, purpose-bred Beagle dogs (three intact females and males), age 5-9.8 years (range) and weighing 11.4-17.9 kg. METHODS: Endotoxaemic shock was induced by injecting 1 mg kg-1Escherichia coli lipopolysaccharide (LPS) intravenously in six sevoflurane-anaesthetized mechanically ventilated Beagles for another project. After 10 minutes, three Ringer's acetate boluses (10 mL kg-1) were administered each over 10 minutes with collection of haemodynamic data immediately before and after each bolus. Thereafter, arterial hypotension was treated with noradrenaline ± dexmedetomidine until arterial pressures increased to a target value. After a wash-out period of 20 minutes another three boluses of fluid were administered and measurements were repeated equally. For each fluid bolus, FR was considered positive when change (Δ) in stroke volume measured by pulmonary artery thermodilution was ≥15%. To test predictive accuracy for FR, we recorded heart rate, invasive arterial, right atrial and pulmonary capillary wedge pressures, pulse wave transit time with haemodynamic monitors, calculated pulse pressure, shock index and rate over pressure evaluation (ROPE) and measured stroke distance and corrected flow time (FTc) with oesophageal Doppler monitoring. RESULTS: A total of 35 measurements (19 positive and 16 negative responses) were evaluated. A FTc < 330 ms, Δ pulse pressure ≥20%, Δ shock index ≤-14% and ΔROPE ≤-17% were the most significant indicators of positive FR with an area under the receiver operating characteristics curve between 0.72 and 0.74. CONCLUSIONS AND CLINICAL RELEVANCE: In endotoxaemic Beagles, none of the assessed haemodynamic variables could predict FR with high sensitivity and specificity.

Use of perfusion index to detect hemodynamic changes in endotoxemic pigs.

OBJECTIVE: The perfusion index (PI) derived from plethysmographic signals provides a noninvasive indication of peripheral perfusion. This study aimed to investigate changes in PI and other hemodynamic variables in pigs subjected to endotoxemia. DESIGN: Prospective experimental study. SETTING: University teaching hospital. ANIMALS: Twelve healthy pigs weighing a mean (± standard deviation [SD]) of 31.7 ± 2.0 kg. INTERVENTIONS: Pigs were divided into control and endotoxin groups (n = 6 each). Endotoxemia was induced by IV infusion of lipopolysaccharide. Heart rate, mean arterial pressure, cardiac index (CI), central venous pressure, systemic vascular resistance index (SVRI), extravascular lung water index (ELWI), Global end-diastolic volume (GEDV) index, and pulmonary permeability index were measured using a transpulmonary thermodilution monitor in all pigs. PI was measured using a pulse oximeter probe attached to the tail. Pao2 , Paco2 , and plasma lactate concentration were measured by blood gas analysis. Measurements were taken at baseline (T0 ). Saline or lipopolysaccharide was then administered for 30 min to all pigs (control or endotoxemia group, respectively), and each parameter was measured every 30 min up to 270 min. Data were analyzed by analysis of variance and Student's t-tests. MEASUREMENTS AND MAIN RESULTS: There were no significant changes in any variables in the control group, but CI, SVRI, PI, ELWI, blood lactate concentration, and Pao2 changed significantly from baseline in the endotoxin group (P < 0.001, P = 0.0048, P < 0.001, P = 0.0064, P < 0.001, and P = 0.0220, respectively). In the endotoxin group, mean (± SD) %PI increased from T0 to 154 ± 34% at T60 (P = .001) and 135 ± 50% at T90 (P =0 .004), which mirrored significant changes in %CI and %SVRI. CONCLUSION: The PI may be useful to detect changes in CI and SVRI.

A preliminary study evaluating cardiac output measurement using Pressure Recording Analytical Method (PRAM) in anaesthetized dogs.

BACKGROUND: Haemodynamic variations normally occur in anaesthetized animals, in relation to the animal status, administered drugs, sympathetic and parasympathetic tone, fluid therapy and surgical stimulus. The possibility to measure some cardiovascular parameters, such as cardiac output (CO), during anaesthesia would be beneficial for both the anaesthesia management and its outcome. New techniques for the monitoring of CO are aimed at finding methods which are non invasive, accurate and with good trending ability, which can be used in a clinical setting. The aim of this study was to compare the Pressure Recording Analytical Method (PRAM) with the pulmonary artery thermodilution (TD) for the measurement of cardiac output in 6 anaesthetized critically ill dogs. RESULTS: Fifty-four pairs of CO measurements were obtained with a median (range) of 3.33 L/min (0.81-7.21) for PRAM-CO and 3.48 L/min (1.41-6.56) for TD-CO. The Bland-Altman analysis showed a mean bias of 0.17 L/min with limits of agreement (LoA) of - 0.46 to 0.81 L/min. The percentage error resulted 18.2%. The 4-quadrant plot analysis showed an acceptable concordance (93%) between the 2 methods. The polar plot showed a good trending ability with the mean angular bias of 3.9° and radial LoA ± 12.1°. CONCLUSIONS: The PRAM resulted in good precision, acceptable concordance and good trending ability for the measure of CO in the anaesthetized dog, representing a promising alternative to thermodilution for the measurement of CO. Among all the pulse contour methods available on the market it is the only one that does not require any calibration or adjustment of the measurement. Further studies are required to verify the ability of this method to accurately measure cardiac output even during unstable hemodynamic conditions.

Clinical monitoring of cardiac output assessed by transoesophageal echocardiography in anaesthetised dogs: a comparison with the thermodilution technique.

BACKGROUND: Cardiac output (CO) is an important haemodynamic parameter to monitor in patients during surgery. However, the majority of the techniques for measuring CO have a limited application in veterinary practice due to their invasive approach and associated complexity and risks. Transoesophageal echocardiography (TEE) is a technique used to monitor cardiac function in human patients during surgical procedures and allows CO to be measured non-invasively. This prospective clinical study aimed to compare the transoesophageal echocardiography using a transgastric view of the left ventricular outflow tract (LVOT) and the thermodilution (TD) technique for the assessment of CO during mean arterial pressure of 65-80 mmHg (normotension) and <65 mmHg (hypotension) in dogs undergoing elective surgery. Eight dogs were pre-medicated with acepromazine (0.05 mg/kg, IM), tramadol (4 mg/kg, IM) and atropine (0.03 mg/kg, IM), followed by anaesthetic induction with propofol (3-5 mg/kg IV) and maintenance with isoflurane associated with a continuous infusion rate of fentanyl (bolus of 3 µg/kg followed by 0.3 µg/kg/min). The CO was measured by TEE (COTEE) and TD (COTD) at the end of expiration during normotension and hypotension (induced by isoflurane). RESULTS: There was a strong positive correlation between COTEE and COTD ​​(r = 0.925; P < 0.0001). The bias between COTD and COTEE was 0.14 ± 0.29 L/min (limits of agreement, -0.44 to 0.72 L/min). The percentage error of CO measured by the two methods was 12.32%. In addition, a strong positive correlation was found between COTEE and COTD during normotension (r = 0.995; P < 0.0001) and hypotension (r = 0.78; P = 0.0223). CONCLUSIONS: The results of this study indicated that the transgastric view of the LVOT by TEE was a minimally invasive alternative to clinically monitoring CO in dogs during anaesthesia. However, during hypotension, the CO obtained by TEE was less reliable, although still acceptable.

Ability of pulse wave transit time to detect changes in stroke volume and to estimate cardiac output compared to thermodilution technique in isoflurane-anaesthetised dogs.

OBJECTIVE: To evaluate the ability of pulse wave transit time (PWTT) to detect changes in stroke volume (SV) and to estimate cardiac output (CO) compared with the thermodilution technique in isoflurane-anaesthetized dogs. STUDY DESIGN: Prospective, experimental study. ANIMALS: Eight adult laboratory dogs. METHODS: The dogs were anaesthetized with isoflurane and mechanically ventilated. Reference CO (TDCO) was measured via a pulmonary artery catheter using the thermodilution technique and reference SV (TDSV) was calculated. PWTT was calculated as the time from the electrocardiogram R-wave peak to the rise point of the pulse oximeter wave. Estimated CO (esCO) was derived from PWTT after calibration with arterial pulse pressure (both non-invasive and invasive methods) and TDCO. Haemodynamic changes were induced by administration of phenylephrine (vasoconstriction), high isoflurane (vasodilatation and negative inotropy) and dobutamine (vasodilatation and positive inotropy). Trending between percentage change in PWTT and TDSV was assessed using concordance analysis and receiver operator characteristic (ROC) curve. The agreement between esCO and TDCO was evaluated using the Bland-Altman method. RESULTS: The direction of percentage change between consecutive PWTT and the corresponding TDSV showed a concordance rate of 95%, with correlation coefficients of -0.86 (p<0.001). Area under the ROC curve for the change in PWTT to detect 15% change in TDSV was 0.91 (p<0.001). TDCO compared with esCO calibrated with invasive and non-invasive blood pressure showed a bias (precision of agreement) of 0.58 (1.54) and 0.57 (1.59) L minute-1 with a percentage error of ±61% and ±63%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: In isoflurane-anaesthetized dogs, PWTT showed a good trending ability to detect 15% changes in SV. This technique is easy to use, inexpensive, non-invasive and could become routine anaesthetic monitoring. However, the agreement between absolute esCO and TDCO was unacceptable.

Comparison of cardiac output measured by use of computed tomography and thermodilution in dogs.

OBJECTIVE To compare cardiac output (CO) measured by use of CT coronary angiography and thermodilution (criterion-referenced standard) at various CO values, record adverse effects, and determine the time needed to measure CO. ANIMALS 5 healthy purpose-bred Beagles (2 males and 3 females). PROCEDURES A prospective nonrandomized crossover study was conducted. Dogs were premedicated with butorphanol tartrate (0.2 mg•kg-1, IM). Anesthesia was induced by IV administration of etomidate (1 to 2 mg•kg-1) and midazolam (0.25 mg•kg-1). Orotracheal intubation was performed, and anesthesia was maintained by administration of isoflurane. The CO was determined by use of thermodilution and by use of CT at 3 CO values. Dobutamine was infused at various rates to obtain the 3 CO values. RESULTS 13 values were obtained and analyzed. The mean ± SD difference between methods was 0.09 ± 0.71 L•min-1 (95% confidence interval [CI], 0.52 to -0.34 L•min-1). Only 1 of 13 values was located on the 100% agreement line (ie, 0 line), 7 of 13 values were located within the 95% CI, and 5 of 13 values were outside the 95% CI. CONCLUSIONS AND CLINICAL RELEVANCE For this study, there was poor agreement between the 2 methods. The 95% CI interval was 0.52 to -0.34 L•min-1, and 5 of 13 values were outside the 95% CI. Therefore, results for the CT method appeared to be inappropriate for use in making clinical decisions.

Cardiac output measured by use of electrocardiogram-gated 64-slice multidector computed tomography, echocardiography, and thermodilution in healthy dogs.

OBJECTIVE To evaluate the accuracy of cardiac output (CO) estimated by use of ECG-gated multidetector CT (MDCT) and 1-, 2-, and 3-D echocardiography and by use of thermodilution. ANIMALS 6 healthy hound-cross dogs. PROCEDURES Electrocardiogram-gated contrast-enhanced 64-slice MDCT and 1-, 2-, and 3-D echocardiography were performed on each dog. The CO for ECG-gated MDCT was calculated as volumetric measurements of stroke volume multiplied by mean heart rate. Echocardiographic left ventricle end-diastolic volumes and end-systolic volumes were measured by use of the Teichholz method (1-D echocardiography) and a single-plane method of disks (2-D echocardiography). Real-time 3-D echocardiographic left ventricle volumes were measured with 3-D functional analysis software on right long-axis and left apical views. The CO of each dog was measured in triplicate by use of thermodilution. Mean CO values, correlations, and limits of agreement for MDCT, echocardiographic modalities, and thermodilution were compared. RESULTS CO measured by use of MDCT, 2-D echocardiography, and 3-D echocardiography had the strongest correlations with CO measured by use of thermodilution. No significant difference in CO was detected between MDCT, any echocardiographic method, and thermodilution. Bland-Altman analysis revealed a systematic underestimation of CO derived by use of MDCT, 2-D echocardiography, and 3-D echocardiography. CONCLUSIONS AND CLINICAL RELEVANCE Use of MDCT, 2-D echocardiography, and 3-D echocardiography to measure CO in healthy dogs was feasible. Measures of CO determined by use of 3-D echocardiography on the right long-axis view were strongly correlated with CO determined by use of thermodilution, with little variance and slight underestimation.

Provision of physiological data and reference values in awake and anaesthetized female sheep aged 6-12 months.

OBJECTIVE: To provide physiological data and reference values in awake and anaesthetized sheep aged 6-12 months. STUDY DESIGN: Descriptive study. ANIMALS: Data from 260 female sheep of the species Ovis orientalis aries aged 6-12 months were extracted from 10 experimental trials. METHODS: Data from pulmonary arterial thermodilution in awake (cohort 1; n = 109) and anaesthetized animals (cohort 2; n = 81), and transpulmonary thermodilution in anaesthetized animals (cohort 3; n = 70) were analysed. General anaesthesia was induced by intramuscular injection of S-ketamine and midazolam and maintained by inhaled isoflurane. Standard laboratory variables (blood gas and clinical chemistry) were assessed. RESULTS: A total of 7553 single data entries from 260 healthy sheep were included. Measurement errors or invalid data documentation meant that 313 data entries (4.1%) were excluded. A small confidence interval for median values was calculated for nearly all variables. The median body weight was 39.8 kg (2.5-97.5th percentile 30.6-48.1 kg). A set of reference values (2.5-97.5th percentiles) is provided for common cardiopulmonary and laboratory variables. Compared to awake animals, haemodynamic variables were markedly influenced by anaesthesia, as reflected by a considerably lower stroke volume index in anaesthetized sheep. There were also differences in stroke volume index between the cohorts of pulmonary artery and transpulmonary thermodilution. CONCLUSIONS AND CLINICAL RELEVANCE: The present work presents a large and consistent database of a variety of physiological variables measured in healthy juvenile female sheep. The data appear to be robust and allow the establishment of standardized inclusion criteria for experimental studies and may help to better evaluate past, present and future research. Differences between pulmonary artery and transpulmonary thermodilution should be assessed in future studies.

Electrical velocimetry for noninvasive cardiac output and stroke volume variation measurements in dogs undergoing cardiovascular surgery.

OBJECTIVE: To compare electrical velocimetry (EV) noninvasive measures of cardiac output (CO) and stroke volume variation (SVV) in dogs undergoing cardiovascular surgery with those obtained with the conventional thermodilution technique using a pulmonary artery catheter. STUDY DESIGN: Prospective experimental trial. ANIMALS: Seven adult Beagle dogs with a median weight of 13.6 kg. METHODS: Simultaneous, coupled cardiac index (CI; CO indexed to body surface area) measurements by EV (CIEV) and the reference pulmonary artery catheter thermodilution method (CIPAC) were obtained in seven sevoflurane-anaesthetized, mechanically ventilated dogs undergoing experimental open-chest cardiovascular surgery for isolated right ventricular failure. Relationships between SVV or central venous pressure (CVP) and stroke volume (SV) were analysed to estimate fluid responsiveness. Haemodynamic data were recorded intraoperatively and before and after fluid challenge. RESULTS: Bland-Altman analysis of 332 matched sets of CI data revealed an overall bias and precision of - 0.22 ± 0.52 L minute-1 m-2 for CIEV and CIPAC (percentage error: 30.4%). Trend analysis showed a concordance of 88% for CIEV. SVV showed a significant positive correlation (r2 = 0.442, p < 0.0001) with SV changes to a volume loading of 200 mL, but CVP did not (r2 = 0.0002, p = 0.94). Better prediction of SV responsiveness (rise of SV index of ≥ 10%) was observed for SVV (0.74 ± 0.09; p = 0.014) with a significant area under the receiver operating characteristic curve in comparison with CVP (0.53 ± 0.98; p = 0.78), with a cut-off value of 14.5% (60% specificity and 83% sensitivity). CONCLUSIONS AND CLINICAL RELEVANCE: In dogs undergoing cardiovascular surgery, EV provided accurate CO measurements compared with CIPAC, although its trending ability was poor. Further, SVV by EV, but not CVP, reliably predicted fluid responsiveness during mechanical ventilation in dogs.

Comparison of Transpulmonary Thermodilution and Calibrated Pulse Contour Analysis with Pulmonary Artery Thermodilution Cardiac Output Measurements in Anesthetized Dogs.

BACKGROUND: Transpulmonary thermodilution (TPTDCO ) and calibrated pulse contour analysis (PCACO ) are alternatives to pulmonary artery thermodilution cardiac output (PATDCO ) measurement. HYPOTHESIS: Ten mL of ice-cold thermal indicator (TI10 ) would improve the agreement and trending ability between TPTDCO and PATDCO compared to 5 mL of indicator (TI5 ) (Phase-1). The agreement and TA between PCACO and PATDCO would be poor during changes in systemic vascular resistance (SVR) (Phase-2). ANIMALS: Eight clinically normal dogs (20.8-31.5 kg). METHODS: Prospective, experimental study. Simultaneous TPTDCO and PATDCO (averaged from 3 repetitions) using TI5 and TI10 were obtained during isoflurane anesthesia combined or not with remifentanil or dobutamine (Phase-1). Triplicate PCACO and PATDCO measurements were recorded during phenylephrine-induced vasoconstriction and nitroprusside-induced vasodilation (Phase-2). RESULTS: Mean bias (limits of agreement: LOA) (L/min), percentage bias (PB), and percentage error (PE) were 0.62 (-0.11 to 1.35), 16%, and 19% for TI5 ; and 0.33 (-0.25 to 0.91), 9%, and 16% for TI10 . Mean bias (LOA), PB, and PE were 0.22 (-0.63 to 1.07), 6%, and 23% during phenylephrine; and 2.12 (0.70-3.55), 43%, and 29% during nitroprusside. Mean angular bias (radial LOA) values were 2° (-10° to 14°) and -1° (-9° to 6°) for TI5 and TI10 , respectively (Phase-1), and 38° (5°-71°) (Phase-2). CONCLUSIONS AND CLINICAL IMPORTANCE: Although TI10 slightly improves the agreement and trending ability between TPTDCO and PATDCO in comparison to TI5 , both volumes can be used for TPTDCO in replacement of PATDCO . Vasodilation worsens the agreement between PCACO and PATDCO . Because of PCACO 's poor agreement and trending ability with PATDCO during SVR changes, this method has limited clinical application.

Evaluation of agreement and trending ability between transpulmonary thermodilution and calibrated pulse contour and pulse power cardiac output monitoring methods against pulmonary artery thermodilution in anesthetized dogs.

OBJECTIVE: To assess agreement and trending ability of transpulmonary thermodilution (TPTD), calibrated pulse contour (PiCCO), and pulse power (PulseCO) methods compared to pulmonary artery thermodilution (PATD) for determination of cardiac output (CO) in anesthetized dogs. DESIGN: Experimental, prospective study. SETTING: University teaching hospital. ANIMALS: Six adult Beagle dogs. INTERVENTIONS: Dogs were anesthetized with sevoflurane and instrumented with pulmonary and femoral artery thermodilution catheters. CO was measured at baseline and at 5, 15, 30, 45, 60, 120, 180, and 240 minutes after IV administration of ketamine or s-ketamine. Baseline PATD and TPTD calibrated PulseCO and PiCCO, respectively. Agreement and trending ability was analyzed with Bland-Altman, concordance, and polar plot methodology. MEASUREMENTS AND MAIN RESULTS: Median (range) CO values of 2.27 (0.98-3.4) L/min were measured with PATD, and 2.8 (1.9-4.04) L/min with TPTD, which resulted in a mean bias (± standard deviation) of -0.66 (± 0.36) L/min. Concordance rate was 91% and radial limits of agreement (RLOA) were ±35°. PATD against PiCCO resulted in a mean bias of -0.71 (± 0.62) L/min and PATD against PulseCO in a mean bias of 0.13 (± 0.46) L/min. The continuous techniques resulted in concordance rates of 77% for PATD-PiCCO and 74% for PATD-PulseCO and RLOA of ±57° and ±60°, respectively. CONCLUSIONS: Intermittent TPTD showed marginal trending ability, while continuous pulse contour and pulse power methods showed poor trending ability over a 4-hour period. The poor performance and possible side effects of the methods tested in this study suggest that they should not be recommended for use in critical patients.

Comparison of cardiac output measurements using transpulmonary thermodilution and conventional thermodilution techniques in anaesthetized dogs with fluid overload.

OBJECTIVE: To evaluate the agreement between cardiac output (CO) values obtained using a transpulmonary thermodilution technique (TPTDCO) and conventional thermodilution technique (TDCO) in anaesthetized dogs with fluid overload. STUDY DESIGN: Prospective experimental study. ANIMALS: Six healthy Beagle dogs aged 7-8 years. METHODS: Dogs were anaesthetized with sevoflurane in oxygen, and catheters were inserted for TPTDCO and TDCO measurement. After instrumentation, baseline CO was measured using each technique at a central venous pressure (CVP) of 3-7 mmHg. Dogs were subsequently administered lactated Ringer's solution and 6% hydroxyethyl starch to induce fluid overload. CO measurements were obtained using each technique at CVP values of 8-12 mmHg, 13-17 mmHg, 18-22 mmHg and 23-27 mmHg. Agreements between CO measurements obtained with the respective techniques were analysed using Dunnett's test, Pearson's correlation coefficient and Bland-Altman analysis. RESULTS: Thirty pairs of CO values were obtained, ranging from 1.45 L minute(-1) to 4.69 L minute(-1) for TPTDCO and from 1.30 L minute(-1) to 4.61 L minute(-1) for TDCO. TPTDCO and TDCO values correlated strongly (r(2)  = 0.915, p < 0.001). The bias and mean relative bias between TPTDCO and TDCO were 0.26 ± 0.30 L minute(-1) (limits of agreement - 0.29 to 0.81 L minute(-1) ) and 9.7%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: TPTDCO and TDCO measurements obtained in anaesthetized dogs during fluid overload exhibited good agreement. Accordingly, transpulmonary thermodilution provides an accurate measurement of CO in dogs with fluid overload.

Produção científica da Enfermagem sobre promoção de saúde, condição crônica e envelhecimento / Producción científica de Enfermería de promoción de la salud, condición crónica y envejecimiento / Nursing scientific production on health promotion, chronic condition, and aging

RESUMOObjetivo:caracterizar a produção científica dos Programas de Pós-Graduação em Enfermagem do Brasil, sobre promoção da saúde com enfoque nas pessoas idosas em condição crônica, no período de 2006 a 2010.Método:pesquisa integrativa, realizada através da busca de dissertações e teses da base de dados do Centro de Estudos e Pesquisas em Enfermagem da Associação Brasileira de Enfermagem, publicados no período de 2006 a 2010, que focassem a promoção de saúde de idosos em condição crônica.Resultados:emergiram cinco categorias temáticas: "Convívio com a doença"; "Tecnologias de cuidado"; "Potencialidades para o autocuidado" "Dimensão psicoespiritual" e "Família cuidadora".Conclusão:pôde-se identificar a assistência de enfermagem como elemento fundamental para promover a saúde do indivíduo idoso e torná-lo mais independente de cuidados para conviver com suas limitações ou incapacidades, mesmo acometido por doenças crônicas.

RESUMENObjetivo:caracterizar la producción científica de la Postgraduate Nursing Brasil, en la promoción de la salud con especial atención a las personas mayores con enfermedades crónicas en el período 2006-2010.Método:la investigación integral realizada mediante la búsqueda de disertaciones y tesis en la base de datos del Centro de Estudios e Investigación en Enfermería Asociación Brasileña de Enfermería, publicada en el período 2006-2010, que se centrará en la promoción de la salud para las personas mayores con enfermedades crónicas.Resultados:cinco temas emergieron: "La convivencia con la enfermedad", "cuidado Technologies", "potencial para el propio cuidado" "dimensión psico-espiritual" y "cuidador familiar".Conclusión:se pudo identificar el cuidado de enfermería como un elemento clave para promover la salud de las personas mayores y que sea una atención más independiente que vivir con limitaciones o incapacidades, aún afectados por enfermedades crónicas.

ABSTRACTObjective:to characterize the scientific production of Postgraduate Programs Nursing in Brazil on health promotion with a focus on elderly people with chronic conditions in the period from 2006 to 2010.Method:integrative research developed by searching for dissertations and theses in the database of the Center for Nursing Studies and Research of the Brazilian Nursing Association published in the period from 2006 to 2010 and which focused on health promotion for elderly people with chronic conditions.Results:five themes emerged: "Living with the disease"; "Technologies of care", "Potential for self-care" "Psycho-spiritual dimension", and "Family caregiver".Conclusion:it was possible to identify nursing care as a key element to promote the health of elderly people and make them more independent in their care so as to live with their limitations or disabilities, even when affected by chronic diseases.

Evaluation of an oesophageal Doppler device for monitoring cardiac output in anaesthetised healthy normotensive dogs.

OBJECTIVES: To compare cardiac output measured by oesophageal Doppler and by thermodilution monitoring and to correlate the Doppler cardiac output-generated minute distance with thermodilution cardiac output in healthy anaesthetised beagle dogs. MATERIALS AND METHODS: Prospective experimental study. Six healthy adult beagle dogs were pre-medicated with intramuscular acepromazine (0 · 05 mg/kg) and methadone (0 · 3 mg/kg). Anaesthesia was induced with intravenous propofol (dose-effect) and maintained with isoflurane in oxygen. Simultaneously, a constant rate infusion of dopamine (3 µg/kg/minute) was administered to the dogs to prevent hypotension. The minute distance, Doppler and thermodilution cardiac outputs were assessed at three different end-tidal concentrations of isoflurane (1 · 0, 1 · 3 and 2 · 0%). RESULTS: Correlation between Doppler and thermodilution cardiac output (r(2) = 0 · 582) and between minute distance and thermodilution cardiac output (r(2) = 0 · 658) were moderately good, but the limits of agreement between Doppler and thermodilution cardiac outputs were above the recommended values (±39%, for a recommended value up to 30%). CLINICAL SIGNIFICANCE: Doppler and minute distance cannot be considered as an alternative method to thermodilution to monitor cardiac output in the healthy anaesthetised dog.