ABSTRACT
The left ventricle, with its thickened myocardial walls, unlike the right ventricle has no measurable geometric shape. It has a conical apex and its function quantification, needs intensive, 2D, 3D and M mode transesophageal echocardiography, which is described in this review.
ABSTRACT
The continuous intravenous administration of isotopic bicarbonate (NaH13CO2) has been used for the determination of the retention of the 13CO2 fraction or the 13CO2 recovered in expired air. This determination is important for the calculation of substrate oxidation. The aim of the present study was to evaluate, in critically ill patients with sepsis under mechanical ventilation, the 13CO2 recovery fraction in expired air after continuous intravenous infusion of NaH13CO2 (3.8 µmol/kg diluted in 0.9 percent saline in ddH2O). A prospective study was conducted on 10 patients with septic shock between the second and fifth day of sepsis evolution (APACHE II, 25.9 ± 7.4). Initially, baseline CO2 was collected and indirect calorimetry was also performed. A primer of 5 mL NaH13CO2 was administered followed by continuous infusion of 5 mL/h for 6 h. Six CO2 production (VCO2) measurements (30 min each) were made with a portable metabolic cart connected to a respirator and hourly samples of expired air were obtained using a 750-mL gas collecting bag attached to the outlet of the respirator. 13CO2 enrichment in expired air was determined with a mass spectrometer. The patients presented a mean value of VCO2 of 182 ± 52 mL/min during the steady-state phase. The mean recovery fraction was 0.68 ± 0.06 percent, which is less than that reported in the literature (0.82 ± 0.03 percent). This suggests that the 13CO2 recovery fraction in septic patients following enteral feeding is incomplete, indicating retention of 13CO2 in the organism. The severity of septic shock in terms of the prognostic index APACHE II and the sepsis score was not associated with the 13CO2 recovery fraction in expired air.
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Carbon Dioxide/metabolism , Carbon Isotopes/metabolism , Pulmonary Gas Exchange , Respiration, Artificial , Sepsis/therapy , APACHE , Critical Illness , Carbon Dioxide/analysis , Carbon Isotopes/administration & dosage , Carbon Isotopes/analysis , Energy Metabolism , Infusions, Intravenous , Oxygen Consumption , Prognosis , Prospective Studies , Reference Values , Sodium Bicarbonate/administration & dosage , Young AdultABSTRACT
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.