Masamichi Hamaguchi

Possible role of increased oxidant stress in multiple organ failure after systemic inflammatory response syndrome

ObjectiveHost response to infection and other forms of tissue injury have been termed systemic inflammatory response syndrome (SIRS). This inflammatory response can frequently be accompanied by oxidative injury in one or more organ systems in the body. The objective of this report was to clarify the possible role of oxidative stress in the development of multiple organ failure (MOF) in patients with SIRS. DesignProspective clinical study. SettingIntensive care unit in a university hospital. PatientsA total of 214 consecutive patients (mean age, 57.1 ± 17.4 yrs; range, 13 to 84 yrs; 148 men and 66 women). At the time of admission, 139 patients fulfilled the clinical criteria for SIRS. InterventionsNone. Measurements and Main ResultsWe measured plasma concentrations of thiobarbituric acid reactant substances (TBARS), as an index of oxidative stress, every day from the point of admission to the intensive care unit until discharge or death. Furthermore, all variables of the SIRS score and the Sequential Organ Failure Assessment score were collected every day. At the time of admission, plasma TBARS concentrations in SIRS patients with MOF were significantly higher than those in SIRS patients without MOF (2.3 ± 0.9 vs. 1.9 ± 0.6 nmol/mL, p < .01), and there was a significant correlation between plasma TBARS concentration and Sequential Organ Failure Assessment score (r2 = .18, p < .001). Furthermore, the duration of SIRS persistence was significantly associated with the percentage increase in plasma TBARS concentration during SIRS persistence in those patients in whom the duration of SIRS was confirmed (r2 = .73, p < .001). The duration of SIRS was significantly higher in patients who developed MOF than in patients who did not develop MOF (6.9 vs. 3.2 days, p < .001). The percentage increase in plasma TBARS concentration during SIRS was also significantly higher in patients who developed MOF than in patients who did not develop MOF (57.1% vs. 15.8%, p < .001). ConclusionsIt can be concluded that processes of oxidative stress in connection with continued SIRS may promote the development of MOF.

Evaluation of oxygen consumption and resting energy expenditure in critically ill patients with systemic inflammatory response syndrome

OBJECTIVE To determine whether oxygen consumption VO2), CO2 production, and resting energy expenditure (REE) in critically ill patients differ in varying grades of systemic inflammatory response syndrome (SIRS). DESIGN Prospective, clinical study. SETTING Intensive care unit at a university hospital. PATIENTS Twenty-six critically ill patients requiring mechanical ventilation. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A total of 100 metabolic measurements were performed. The grade of SIRS and the Acute Physiology and Chronic Health Evaluation II score were evaluated at the time of the metabolic cart study. VO2 and REE differed among the groups inadequate for SIRS (non-SIRS), with SIRS without infection (nonseptic SIRS), and with SIRS with infection (septic SIRS) (125 +/- 37 mL/min/m2 and 855 +/- 204 kcal/day/m2, 135 +/- 33 mL/min/m2 and 948 +/- 214 kcal/day/m2, and 166 +/- 55 mL/min/m2 and 1149 +/- 339 kcal/day/m2, respectively; p < .005). Patients with septic SIRS had higher VO2 and REE than patients with non-SIRS and nonseptic SIRS. CONCLUSION VO2 and REE differ among groups of patients with non-SIRS, nonseptic SIRS, and septic SIRS. Patients with septic SIRS have higher VO2 and REE than patients with non-SIRS or nonseptic SIRS. The present study shows that classifying patients into three grades (non-SIRS, nonseptic SIRS, and septic SIRS) is a valid predictor of metabolic stress in critically ill patients.

NITROGEN DIOXIDE PRODUCTION IN A NITRIC OXIDE INHALATION SYSTEM USING THE SERVO VENTILATOR 900C

During nitric oxide (NO) inhalation therapy, toxicity may be produced by the reactive metabolite nitrogen dioxide (NO2). The purpose of the present study was to determine the NO2 concentration in a NO inhalation system used for respiratory failure in children at relatively low concentrations of NO (< 20 ppm). The production of NO2 in the NO inhalation system using the Servo Ventilator 900C connected to the test lung under each of 30 combinations of NO concentrations (0, 4, 8, 12, 16, and 19 ppm) and inspired oxygen (O2) concentrations (21, 40, 60, 80, and 100%). Pressure controlled ventilation was used with a respiratory rate of 20 breaths/min. NO and NO2 measurements were obtained on the inspiratory side of the Y‐piece connected to the test lung. At a given NO level, increases in the concentration of inspired O2 resulted in increases in the concentration of NO2 produced, as did increases in the amount of NO at a given concentration of O2. The mean NO2 concentration at the inspiratory site of the Y‐piece did not exceed 0.05 ppm (the limit of NO2 as an outdoor air pollutant in the United States) when the NO concentration did not exceed 8 ppm, regardless of the O2 concentration. NO inhalation therapy for children with severe respiratory failure using the Servo Ventilator 900C can be performed safely when the concentration of NO does not exceed 8 ppm.

INHALED NITRIC OXIDE FOLLOWED BY EXTRACORPOREAL MEMBRANE OXYGENATION IN RESUSCITATING A NEWBORN WITH HYPOXEMIA

In a newborn requiring cardiopulmonary resuscitation because of hypoxemia due to sepsis (oxygenation index > 40), inhalation of nitric oxide (NO) in a concentration of 16p.p.m. improved oxygenation and restored spontaneous circulation. Cannulation for extracorporeal membrane oxygenation (ECMO) then was performed safely under NO inhalation. ECMO was discontinued on day 7, and on day 14 the infant was extubated. During follow‐up examination at 5 months of age no neurological abnormalities were found. This case shows the usefulness of combining inhaled NO and ECMO.