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.

Indirect calorimetry can be used to measure cardiac output in septic patients?

PURPOSE: The aim of this study was to compare two different cardiac output (CO) monitoring systems based on the thermodilution principle (Thermo-CO) and indirect calorimetry (Fick mixed-CO) in septic patients. METHODS: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Nineteen patients aged on average 45.4 +/- 21.5 years were enrolled in the study. Four series of hourly measurements by the two techniques were carried out simultaneously. RESULTS: No significant differences were observed between Thermo-CO and Fick mixed-CO (7.0 +/- 1.8 L.min-1 and 6.4 +/- 1.7 L.min-1.). Parallel analysis of Fick mixed-CO and Fick atrial-CO was performed introducing a correction factor for the eight atrial samples in order to adjust the values of oxygen saturation obtained from atrial blood (Fick corrected atrial-CO) to those obtained from mixed venous blood. No significant differences could be detected between Fick mixed-CO and Fick corrected atrial-CO. The correlation coefficients of Thermo CO/Fick mixed-CO and Fick mixed-CO/Fick corrected atrial-CO were 0.84 and 0.94, respectively. CONCLUSION: We observed that the agreement between the two methods was satisfactory on the basis of the decisions made for treatment. Indirect calorimetry is useful to measure CO in patients with septic shock.

Indirect calorimetry can be used to measure cardiac output in septic patients? / A calorimetria indireta pode ser utilizada para medir o débito cardíaco em pacientes sépticos?

PURPOSE: The aim of this study was to compare two different cardiac output (CO) monitoring systems based on the thermodilution principle (Thermo-CO) and indirect calorimetry (Fick mixed-CO) in septic patients. METHODS: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Nineteen patients aged on average 45.4 ± 21.5 years were enrolled in the study. Four series of hourly measurements by the two techniques were carried out simultaneously. RESULTS: No significant differences were observed between Thermo-CO and Fick mixed-CO (7.0 ± 1.8 L.min-1 and 6.4 ± 1.7 L.min-1.). Parallel analysis of Fick mixed-CO and Fick atrial-CO was performed introducing a correction factor for the eight atrial samples in order to adjust the values of oxygen saturation obtained from atrial blood (Fick corrected atrial-CO) to those obtained from mixed venous blood. No significant differences could be detected between Fick mixed-CO and Fick corrected atrial-CO. The correlation coefficients of Thermo CO/Fick mixed-CO and Fick mixed-CO/Fick corrected atrial-CO were 0.84 and 0.94, respectively. CONCLUSION: We observed that the agreement between the two methods was satisfactory on the basis of the decisions made for treatment. Indirect calorimetry is useful to measure CO in patients with septic shock.

OBJETIVO: O objetivo deste estudo foi comparar as medidas do débito cardíaco (DC) obtidas pela termodiluição (DC-termo) e pela calorimetria indireta (DC-Fick misto) em pacientes com choque séptico. MÉTODOS: Estudo prospectivo em pacientes sépticos internados em unidade de terapia intensiva de um hospital universitário. Foram estudados 19 pacientes (45,4 ± 21,5 anos). Foram realizadas quatro séries de medidas do DC pelos dois métodos, simultaneamente. RESULTADOS: Não houve diferenças significativas entre os valores do DC-termo e DC-Fick misto (7,0 ± 1,8 L.min-1 e 6,4 ± 1,7 L.min-1, respectivamente). Na avaliação dos oito casos (DC-Fick misto/DC Fick atrial), introduziu-se um fator de correção para aproximar os valores do conteúdo de O2 atrial (DC-Fick atrial corrigido) com o venoso misto. Não houve diferença significativa do DC-Fick misto e DC-Fick atrial corrigido nos 4 tempos. A correlação foi de 0.84 para o DC-termo/DC-Fick misto e de 0.94 para o DC-Fick misto/DC-Fick atrial corrigido. CONCLUSÃO: A calorimetria indireta é um bom método para a medida do DC em pacientes vítimas de choque séptico, sobretudo nos casos onde a monitorização hemodinâmica invasiva não está disponível ou está contra indicada.

Indirect calorimetry can be used to measure cardiac output in septic patients? / A calorimetria indireta pode ser utilizada para medir o débito cardíaco em pacientes sépticos?

PURPOSE: The aim of this study was to compare two different cardiac output (CO) monitoring systems based on the thermodilution principle (Thermo-CO) and indirect calorimetry (Fick mixed-CO) in septic patients. METHODS: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Nineteen patients aged on average 45.4 ± 21.5 years were enrolled in the study. Four series of hourly measurements by the two techniques were carried out simultaneously. RESULTS: No significant differences were observed between Thermo-CO and Fick mixed-CO (7.0 ± 1.8 L.min-1 and 6.4 ± 1.7 L.min-1.). Parallel analysis of Fick mixed-CO and Fick atrial-CO was performed introducing a correction factor for the eight atrial samples in order to adjust the values of oxygen saturation obtained from atrial blood (Fick corrected atrial-CO) to those obtained from mixed venous blood. No significant differences could be detected between Fick mixed-CO and Fick corrected atrial-CO. The correlation coefficients of Thermo CO/Fick mixed-CO and Fick mixed-CO/Fick corrected atrial-CO were 0.84 and 0.94, respectively. CONCLUSION: We observed that the agreement between the two methods was satisfactory on the basis of the decisions made for treatment. Indirect calorimetry is useful to measure CO in patients with septic shock.(AU)

OBJETIVO: O objetivo deste estudo foi comparar as medidas do débito cardíaco (DC) obtidas pela termodiluição (DC-termo) e pela calorimetria indireta (DC-Fick misto) em pacientes com choque séptico. MÉTODOS: Estudo prospectivo em pacientes sépticos internados em unidade de terapia intensiva de um hospital universitário. Foram estudados 19 pacientes (45,4 ± 21,5 anos). Foram realizadas quatro séries de medidas do DC pelos dois métodos, simultaneamente. RESULTADOS: Não houve diferenças significativas entre os valores do DC-termo e DC-Fick misto (7,0 ± 1,8 L.min-1 e 6,4 ± 1,7 L.min-1, respectivamente). Na avaliação dos oito casos (DC-Fick misto/DC Fick atrial), introduziu-se um fator de correção para aproximar os valores do conteúdo de O2 atrial (DC-Fick atrial corrigido) com o venoso misto. Não houve diferença significativa do DC-Fick misto e DC-Fick atrial corrigido nos 4 tempos. A correlação foi de 0.84 para o DC-termo/DC-Fick misto e de 0.94 para o DC-Fick misto/DC-Fick atrial corrigido. CONCLUSÃO: A calorimetria indireta é um bom método para a medida do DC em pacientes vítimas de choque séptico, sobretudo nos casos onde a monitorização hemodinâmica invasiva não está disponível ou está contra indicada.(AU)

[Comparison of cardiac output measurement in critical patients using transesophageal Doppler or thermodilution: a preliminary report]. / Determinación y análisis comparativo de gasto cardíaco en enfermos críticos mediante Doppler transesofágico y termodilución en bolos: experiencia preliminar.

BACKGROUND: Cardiac output can be measured non invasively by transesophageal Doppler. This is an alternative to measure it by thermodilution with a catheter in the pulmonary artery. AIM: To compare both methods of cardiac output measurement. MATERIAL AND METHODS: Simultaneous measurement of cardiac output by transesophageal Doppler and thermodilution with a catheter in the pulmonary artery in four male critical patients, aged 60+/-12 years, hospitalized in a University Hospital. The Bland and Altman method to compare the concordance between two measurements, was used. RESULTS: Forty measurements were performed. The results of both methods had a correlation coefficient of 0.98. According to the Bland and Altman method, the difference between both methods was -0.5 L with a precision of 0.52 L/min (95% confidence interval -1.51 to 0.52 L/min). Considering that a change between two sequential measurements is considered significant when the difference is more than 15%, both measurements agreed in 83% of cases, that there was a change in cardiac output. CONCLUSIONS: Transesophageal Doppler is a promising non invasive technique to measure cardiac output in critical care patients. It becomes a valid alternative to the thermodilution technique. This preliminary experience must be confirmed in a larger series.

Determinación y análisis comparativo de gasto cardíaco en enfermos críticos mediante Doppler transesofágico y termodilución en bolos: Experiencia preliminar / Comparison of cardiac output measurement in critical patients using transesophageal Doppler or thermodilution: A preliminary report

Background: Cardiac output can be measured non invasively by transesophageal Doppler. This is an alternative to measure it by thermodilution with a catheter in the pulmonary artery. Aim: To compare both methods of cardiac output measurement. Material and methods: Simultaneous measurement of cardiac output by transesophageal Doppler and thermodilution with a catheter in the pulmonary artery in four male critical patients, aged 60±12 years, hospitalized in a University Hospital. The Bland and Altman method to compare the concordance between two measurements, was used. Results: Forty measurements were performed. The results of both methods had a correlation coefficient of 0.98. According to the Bland and Altman method, the difference between both methods was -0.5 L with a precision of 0.52 L/min (95% confidence interval -1.51 to 0.52 L/min). Considering that a change between two sequential measurements is considered significant when the difference is more than 15%, both measurements agreed in 83% of cases, that there was a change in cardiac output. Conclusions:Transesophageal Doppler is a promising non invasive technique to measure cardiac output in critical care patients. It becomes a valid alternative to the thermodilution technique. This preliminary experience must be confirmed in a larger series.

Comparison between cardiac output values measured by thermodilution and partial carbon dioxide rebreathing in patients with acute lung injury

CONTEXTO: A termodiluição, considerada técnica padrão para medida do débito cardíaco em pacientes graves, não é isenta de riscos relevantes. Faz-se necessário encontrar métodos alternativos não invasivos, automáticos, simples e acurados para monitorar o débito cardíaco à beira do leito. OBJETIVO: Comparar as medidas do débito cardíaco obtido com os métodos termodiluição e reinalação parcial de gás carbônico em pacientes com lesão pulmonar aguda em dois níveis de gravidade (índice de lesão pulmonar - LIS abaixo de 2,5 grupo A; e acima de 2,5, grupo B). TIPO DO ESTUDO: Comparativo, prospectivo, controlado. LOCAL: Unidades de Terapia Intensiva de dois hospitais-escola. MÉTODOS: Vinte pacientes acometidos de insuficiência respiratória aguda (PaO2/FiO2 < 300), sob ventilação pulmonar artificial, nos quais foram realizadas 294 medidas, 164 medidas no grupo A (n = 11) e 130 no grupo B (n = 9),variando de 14 a 15 medidas por paciente, foram estudados. Débito cardíaco foi medido com termodiluição e reinalação parcial de gás carbônico. RESULTADOS: A correlação entre os métodos estudados foi fraca no grupos A (r = 0,52, p < 0,001*) e no B: r = 0,47, p < 0,001*). A aplicação do teste de Bland-Altman permitiu evidenciar a discordância entre os métodos (grupo A: -0,9 ± 2,71 l/min; IC 95% = - 1,14 a -0,48; e grupo B: -1,75 ± 2,05 l/min (IC 95% = -2,11 a -1,4). A comparação dos resultados (testes t para grupos emparelhados e Mann-Whitney) obtidos nos grupos e entre os grupos de estudo revelou diferenças ( p = 0,00*, p < 0,05). DISCUSSAO: Erros em estimar o CaCO2 (conteúdo arterial de CO2) através da ETCO2 (CO2 de final de corrente) e situações de circulação hiperdinâmica associados a espaço morto e/ou shunt possivelmente expliquem nossos resultados. CONCLUSAO: Em pacientes com lesão pulmonar aguda, o débito cardíaco determinado pela reinalação parcial de gás carbônico difere dos valores medidos com termodiluição. Esta diferença se acentua com a maior gravidade da lesão pulmonar.

Comparison between cardiac output values measured by thermodilution and partial carbon dioxide rebreathing in patients with acute lung injury.

CONTEXT: Thermodilution, which is considered to be a standard technique for measuring the cardiac output in critically ill patients, is not free from relevant risks. There is a need to find alternative, noninvasive, automatic, simple and accurate methods for monitoring cardiac output at the bedside. OBJECTIVE: To compare cardiac output measurements by thermodilution and partial carbon dioxide rebreathing in patients with acute lung injury at two levels of severity (lung injury score, LIS: below 2.5, group A; and above 2.5, group B). TYPE OF STUDY: Comparative, prospective and controlled study. SETTING: Intensive Care Units of two university hospitals. METHODS: Cardiac output was measured by thermodilution and partial carbon dioxide rebreathing. Twenty patients with acute lung failure (PaO2/FiO2 < 300) who were under mechanical ventilation and from whom 294 measurements were taken: 164 measurements in group A (n = 11) and 130 in group B (n = 9), ranging from 14 to 15 determinations per patient. RESULTS: There was a poor positive correlation between the methods studied for the patients from groups A (r = 0.52, p < 0.001) and B (r = 0.47, p < 0.001). The application of the Bland-Altman test made it possible to expose the lack of agreement between the methods (group A: -0.9 +/- 2.71 l/min; 95% CI = -1.14 to -0.48; and group B: -1.75 +/- 2.05 l/min; 95% CI = -2.11 to -1.4). The comparison of the results (Student t and Mann-Whitney tests) within each group and between the groups showed significant difference (p = 0.000, p < 0.05). DISCUSSION: Errors in estimating CaCO2 (arterial CO2 content) from ETCO2 (end-tidal CO2) and situations of hyperdynamic circulation associated with dead space and/or increased shunt possibly explain our results. CONCLUSION: Under the conditions of this study, the results obtained allow us to conclude that, in patients with acute lung injury, the cardiac output determined by partial rebreathing of CO2 differs from the measurements obtained by thermodilution. This difference becomes greater, the more critical the lung injury is.