[Postoperative hyponatremia in pediatric patients]. / Hiponatremia postoperatoria en pacientes pediátricos.

Fluid replacement therapy for pediatric patients in the past 50 years has meant the infusion of hypotonic solutions in amounts calculated using the Holliday-Segar formula. Recent studies have focused attention on the incidence of postoperative hyponatremia and associated morbidity and mortality rates, generating debate on the advisability of perioperative fluid therapy and calling into question both the effectiveness of this strategy and the quantities used. We report 3 cases of hyponatremic encephalopathy in children following different types of minor surgery. Free water excretion by the kidneys is known to be a conditioning factor in this therapy, yet the ideal way to provide pediatric fluid therapy is still hotly debated. The question cannot be resolved until large randomized clinical trials are carried out to compare the use of hypotonic and isotonic solutions. Some general recommendations can be offered, however, in the interest of lowering the incidence of electrolyte disturbances and diminishing their repercussions.

[In memoriam Fidel Pagés Miravé (1886-1923) on the 75th anniversary of the publication of "Anesthesia metamérica"]. / En memoria de Fidel Pagés Miravé (1886-1923) en el LXXV aniversario de la publicación de "Anestesia metamérica".

Fidel Pagés was born in Huesca on the 26th of January 1886. He completed his secondary studies in the same city, later receiving his degree in medicine and surgery from University of Zaragoza (1908) with high honors. The same year he joined the army medical corp, to be sent to serve in Melilla in 1909 with a rank of second medical officer. After being promoted in 1911 to first medical officer, he served in Tarragona, Toledo, Madrid (where received his doctoral degree), Ciudad Real, and once again in Madrid. In 1913 Pagés married and was destined to Mahón, only to return to work at the War Ministry in Madrid in 1915, after a brief sojourn in Alicante. The same year he placed first in competition for a staff position at Madrid's Hospital Provincial. In 1917, during World War I, he inspected POW camps in Austria and Hungary, while also serving in the military hospital in Vienna. In 1919 he became the founding editor of Revista Española de Cirugía, which published "Anestesia metamérica" in 1921, simultaneous to its publication in Revista de Sanidad Militar. In 1920 on he was assigned to Madrid's Hospital Militar de Urgencia, but was also briefly sent to Melilla in 1921 as a consequence of the military "Disaster at Annual". In 1922 he was promoted to the rank of Medical Commandant. On the 21st of September 1923, Pagés died in a traffic accident while returning to Madrid from San Sebastián. His work was soon forgotten, as can be seen from the credit long given to the Italian surgeon Dogliotti for the discovery of epidural anesthesia. Only with passing time, and through the effort of Argentinian and Spanish physicians, has the world come to recognize Pagés as the original author of this technique.

Monitorización continua de la saturación de oxígeno de la hemoglobina en la sange venosa mixta durante la anestesia torácia con ventilación selectiva unipulmonar

Objetivos. El decúbito lateral, la toracotomía y la ventilación selectiva unipulmonar producen graves alteraciones de la oxigenación. El objeto del estudio es examinar la utilidad de la monitorizaciónc continua de la saturación venosa mixta (SvO2) en condiciones especiales. Pacientes y Método. A 23 pacientes programados para reseción pulmonar mediante toracotomía en posición de cúbito lateral con ventilación unipulmonar, se les monitorizó continuamente la SvO2 mediante un sistema de oximetría de reflexión y un catéter de arteria pulmonar de fibra óptica (Abbott Oximetris 3). Se obtuvieron perfiles cardiorespiratoriosa los 15 min. de la inducción (M1), 15 min del decúbito lateral (M2), 5 min de la pleurotomía (M3), a los 5 min (M4) y 20 min (M5) del colapso pulmonar, 5 min del cierre de la pared torácica (M6) y 5 min del decúbito supino (M7). La SVO2 desciende de manera no estadísticamente signoficativa y alcanza su valor mínimo en M5, experimentando un ascenso significativo en M6 (p<0.05). Se encuentra una correlación significativa en todas la mediciones entre los valores de la SVO2 medicos con Oximetrix3 y cooxímetro. Con las C(a-v)O2 y EO2 existe correlación significativa en todas las mediciones con la PV=2 y Qva/Qt, excepto en la M6. el IVO2 presenta correlación inversa de M1 a M5 y el IC directa sólo emn M6 y M7, como el IDO2. Con la PaO2 y SaO2 hay correlación significativa durante la ventilación pulmonar (M4 y M5) y posteriormente M6. Los cambios combinados en la SaO2 el IC sólo explican los cambios en la SVO2 durante la ventilación selectiva y después de ésta y más probable que reflejan cambios en la SAO2 que en la IC. Conclusiones. En las condiciones del estudio, la monitorización continua con SVO2 es un método fiable que indica primariamente la oxigenación y secundariamente el GC, en especial durante la ventilación unipulmonar, y refleja el balance aporte/demanda de oxígeno de los tejidos perfundidos. Pero dada su falta de especificidad, ante un descenso brusco de sus valores, se realizarán determinaciones hemodinámicas y gasimétricas para diagnosticar la causa de la alteración de dicho balance aporte/demanda

[Comparison of oxygen saturations in mixed venous and central blood during thoracic anesthesia with selective single-lung ventilation]. / Comparición de las saturaciones de oxígeno en sangre venosa mixta y central durante la anestesia torácica con ventilación selectiva unipulmonar.

OBJECTIVES: To establish the ratio of oxygen saturation in mixed venous to that of central venous blood in patients undergoing thoracic surgery, in order to rationalize use of the pulmonary arterial catheter. MATERIAL AND METHODS: We compared simultaneous spectrophotometric in vivo measurements for SvO2 [Abbott Oximetrix 3/SvO2 (O)] and in vitro analysis of blood taken from the distal opening of the catheter (co-oximeter/SvO2 [CO]), with in vitro analysis of central venous blood from the superior vena cava (co-oximetry/SvcO2 [CO]) for 23 patients scheduled for lung resection by thoracotomy in lateral decubitus with single lung ventilation and the same type of monitoring and anesthesia. Measurements were taken 15 min after induction (M1), after 15 minutes in lateral decubitus (M2), 5 minutes after pleurotomy (M3), 5 min (M4) and 20 min (M5) after lung collapse, 5 min after closure of the thoracic wall (M6) and after 5 min supine (M7). RESULTS: SvO2(O) was higher than SvcO2 (CO) at M1, M3, M6 and M7 and the mean difference between the two concentrations was always less than 0.9%. SvcO2 (CO) was always higher than SvO2 (CO) (M1 to M7) and the mean difference was less than 1.3%. Simple linear correlation was significant (p < 0.001) for each of the measurements as well as for the whole sample. Both bias (0.2 and 0.7%) and its standard deviation (2.7 and 2.5%) between the two techniques were small and the differences between all measurements were less than 5% in 97 and 95.6%. CONCLUSION: For thoracic anesthesia in patients who are not good candidates for catheterization of the pulmonary artery, continuous measurement of SvO2 may be substituted for that of SvcO2 in order to monitor the balance of supply/demand.

[Continuous monitoring of hemoglobin oxygen saturation in mixed venous blood during thoracic anesthesia with selective single-lung ventilation]. / Monitorización continua de la saturación de oxígeno de la hemoglobina en la sangre venosa mixta durante la anestesia torácica con ventilación selectiva unipulmonar.

OBJECTIVES: The lateral decubitus position, the thoracotomy and selective single-lung ventilation all cause serious changes in oxygenation. The aim of this study is to examine the usefulness of continuous monitoring of mixed venous saturation (SvO2) under these conditions. MATERIAL AND METHODS: Twenty-three patients scheduled for pulmonary resection by thoracotomy in lateral decubitus position with single-lung ventilation were monitored continuously for SvO2 by reflection oximetry and a fiber-optic catheter in the pulmonary artery (Abbot Oximetrix 3). Cardiorespiratory profiles were obtained 15 minutes after induction (M1), after 15 minutes in lateral decubitus position (M2), 5 min after start of pleurotomy (M3), 5 min (M4) and 20 min (M5) after lung collapse, 5 min after closure of the thoracic wall (M6), and after 5 min in supine decubitus position (M7). RESULTS: The decrease in SvO2 was not statistically significant. It reached its lowest level at M5 and rose significantly in M6 (p < 0.05). For all SvO2 measurements there was a significant correlation between Oximetrix 3 and Co-oximeter readings. C(a-v)O2 and O2 uptake correlated significantly at all measurements, as did those of PvO2 and Qva/Qt except at M6. VO2I correlated inversely from M1 to M5, and CI an DO2I only at M6 and M7. PaO2 and SaO2 were significantly correlated during single-lung ventilation (M4 and M5) and later (M6). The combined changes in SaO2(a-v) and CI explain the changes in SvO2 only during and after selective ventilation, and the changes are more likely to be reflected by SaO2 than by CI. CONCLUSIONS: Under the conditions studied, continuous monitoring of SvO2 is a reliable method, indicating primarily oxygenation, and cardiac output secondarily, particularly during single-lung ventilation, and also reflecting the balance of oxygen supply and demand in tissues. Given the lack of specificity, however, hemodynamic and gas measurements must be taken to diagnose the cause of any change in the supply/demand balance whenever there is a sudden drop in SvO2.