Francisco Antônio Coletto

Correlação entre o consumo de oxigênio obtido pelo método de Fick e pela calorimetria indireta no paciente grave

OBJECTIVE To compare the oxygen consumption index measured by using indirect calorimetry (VO2I Delta) with a portable metabolic cart and calculated according to Ficks principle (VO2 I Fick) in critically ill patients. METHODS Fourteen patients (10 men and 4 women, mean age 39.4 +/- 5.4 years) were analyzed, 5 of them trauma victims and 9 sepsis victims. The following mean scores were obtained for these patients: APACHE II = 21.3+/-1.8, ISS = 24.8+/-6, and sepsis score = 19.6+/-2.3. The mortality risk (odds ratio), calculated from APACHE II, was 41.9+/-7.1%. All patients underwent mechanical ventilation and invasive hemodynamic monitoring with a Swan-Ganz catheter. VO2 was obtained using the 2 methods (VO2I Delta and VO2I Fick) at 4 different times (T1-T4). RESULTS A good correlation was found between the 2 methods (r=0.77) for the mean of the 4 serial measurements. No statistically significant differences were observed between indirect calorimetry and Ficks equation at T1 (VO2I Delta = 138+/-28 and VO2I Fick = 59+/-38 mL.min-2.m-2, P=0.10) and T3 (VO2I Delta = 144+/-26 and VO2I Fick = 158+/-35 mL.min-2.m-2, P=0.14), but a significant difference was observed at T2 (VO2I Delta = 141+/-27 and VO2I Fick = 155+/-26 mL.min-2.m-2, P=0.03) and T4 (VO2I Delta = 145+/-24 and VO2I Fick = 162+/-26 mL.min-2.m-2, P=0.01). CONCLUSION We may state that indirect calorimetry can be used for oxygen consumption analysis in critically ill patients and is as efficient as Ficks reverse equation, with the benefit of being a noninvasive and risk-free procedure.

Mechanical thrombectomy with solitaire stent retrieval for acute ischemic stroke in a Brazilian population

OBJECTIVE: Large vessel occlusion in acute ischemic stroke is associated with low recanalization rates under intravenous thrombolysis. We evaluated the safety and efficacy of the Solitaire AB stent in treating acute ischemic stroke. METHODS: Patients presenting with acute ischemic stroke were prospectively evaluated. The neurological outcomes were assessed using the National Institutes of Health Stroke Scale and the modified Rankin Scale. Time was recorded from the symptom onset to the recanalization and procedure time. Recanalization was assessed using the thrombolysis in cerebral infarction score. RESULTS: Twenty-one patients were evaluated. The mean patient age was 65, and the National Institutes of Health Stroke Scale scores ranged from 7 to 28 (average 17±6.36) at presentation. The vessel occlusions occurred in the middle cerebral artery (61.9%), distal internal carotid artery (14.3%), tandem carotid occlusion (14.3%), and basilar artery (9.5%). Primary thrombectomy, rescue treatment and a bridging approach represented 66.6%, 28.6%, and 4.8% of the performed procedures, respectively. The mean time from symptom onset to recanalization was 356.5±107.8 minutes (range, 80-586 minutes). The mean procedure time was 60.4±58.8 minutes (range, 14-240 minutes). The overall recanalization rate (thrombolysis in cerebral infarction scores of 3 or 2b) was 90.4%, and the symptomatic intracranial hemorrhage rate was 14.2%. The National Institutes of Health Stroke Scale scores at discharge ranged from 0 to 25 (average 6.9±7). At three months, 61.9% of the patients had a modified Rankin Scale score of 0 to 2, with an overall mortality rate of 9.5%. CONCLUSIONS: Intra-arterial thrombectomy with the Solitaire AB device appears to be safe and effective. Large randomized trials are necessary to confirm the benefits of this approach in acute ischemic stroke.

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.

13CO2 recovery fraction in expired air of septic patients under mechanical ventilation

Pro-Reitoria de Pesquisa da Universidade de Sao Paulo, and Fundacao de Amparo ao Ensino, Pesquisa e Assistencia, Hospital das Clinicas, Faculdade de Medicina de Ribeirao Preto, USP, and FAPESP

Correction Braz J Med Biol Res 2008; 41 (7): 563-570 - 13CO2 recovery fraction in expired air of septic patients under mechanical ventilation

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 micromol/kg diluted in 0.9% 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%, which is less than that reported in the literature (0.82 +/- 0.03%). 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.