RESUMEN
OBJECTIVE: Define the pressure-volume relationship of the cuff of paediatric cuffed tracheal tubes. STUDY DESIGN: Experimental study. MATERIALS AND METHODS: The cuff pressure was measured after incremental 0.1 ml filling volumes for 6 sizes (3.0 to 5.5 mm of internal diameter) of paediatric high volume-low pressure cuffed-tracheal tubes. The pressure-volume relationship of the cuff was assessed with and without resistance to the filling. Results were expressed with medium +/- SD. RESULT: Each increment increased the cuff pressure, without resistance, of 7.3 +/- 1.7 mmHg for sizes 3.0, 3.5 and 4.0, 4.8 +/- 1.6 mmHg for size 4.5, and 2.3 +/- 0.9 mmHg for sizes 5 and 5.5. The resistance decreased the filling volume of the cuff for each size of tracheal tubes. CONCLUSION: The margin of safety provided by cuff of smallest cuffed tracheal tubes is too small. Then, the smallest sizes (3.0 to 4.5) should not be called low pressure-high volume cuff.
Asunto(s)
Intubación Intratraqueal/instrumentación , Presión del Aire , Niño , Humanos , Tráquea/anatomía & histologíaRESUMEN
UNLABELLED: We compared the effects of position and fraction of inspired oxygen (F(IO)2) on oxygenation during thoracic surgery in 24 consenting patients randomly assigned to receive an F(IO)2 of 0.4 (eight patients, Group 0.4), 0.6 (eight patients, Group 0.6), or 1.0 (eight patients, Group 1.0) during the periods of two-lung (TLV) and one-lung ventilation (OLV) in the supine and lateral positions. TLV and OLV were maintained while the patients were first in the supine and then in the lateral position for 15 min each. Thereafter, respiratory mechanical data were obtained, and arterial blood gas samples were drawn. Pao2 decreased during OLV compared with TLV in both the supine and lateral positions. In all three groups, Pao2 was significantly higher during OLV in the lateral than in the supine position: 101 (72-201) vs 63 (57-144) mm Hg in Group 0.4; 268 (162-311) vs 155 (114-235) mm Hg in Group 0.6; and 486 (288-563) vs 301 (216-422) mm Hg in Group 1.0, respectively (P < 0.02, Wilcoxon's signed rank test). We conclude that, compared with the supine position, gravity augments the redistribution of perfusion as a result of hypoxic pulmonary vasoconstriction, when patients are in the lateral position, which explains the higher Pao2 during OLV. IMPLICATIONS: This study compares oxygenation during thoracic surgery during periods of two-lung and one-lung ventilation with patients in the supine and lateral positions when using three different fraction of inspired oxygen values. Arterial oxygen tension was decreased in all three groups during one-lung ventilation in comparison with the two-lung ventilation values, but the decrease was significantly less in the lateral, compared with the supine position.
Asunto(s)
Enfermedades Pulmonares Obstructivas/fisiopatología , Consumo de Oxígeno/fisiología , Postura/fisiología , Respiración Artificial , Adulto , Anciano , Análisis de los Gases de la Sangre , Método Doble Ciego , Femenino , Humanos , Pulmón/cirugía , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Pruebas de Función Respiratoria , Mecánica Respiratoria/fisiología , Posición Supina/fisiologíaRESUMEN
Following surgical closure of an interventricular communication complicating an anterior myocardial infarction, a 74-year-old woman developed severe right ventricular failure and hypoxemia due to the opening of a patent foramen ovale (PFO). Mean pulmonary artery pressure was 24 mm Hg. Treatment with inhaled nitric oxide (5 ppm) increased PaO2 from 47 to 90 mm Hg (FIo(2)1). The present observation points out that nitric oxide inhalation could be useful in the management of severe hypoxemia from a right-to-left shunt due to a PFO even when there is no significant pulmonary hypertension present.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , Defectos del Tabique Interatrial/tratamiento farmacológico , Óxido Nítrico/uso terapéutico , Consumo de Oxígeno/efectos de los fármacos , Arteria Pulmonar/efectos de los fármacos , Administración por Inhalación , Anciano , Femenino , Defectos del Tabique Interventricular/complicaciones , Defectos del Tabique Interventricular/cirugía , Humanos , Hipertensión Pulmonar , Hipoxia/etiología , Infarto del Miocardio/complicaciones , Óxido Nítrico/administración & dosificación , Intercambio Gaseoso Pulmonar/efectos de los fármacos , Disfunción Ventricular Derecha/etiologíaRESUMEN
Flow-volume loops were monitored continuously in 39 patients undergoing thoracic surgery requiring one-lung ventilation. In 26 of the 39 patients (67%), auto-positive end-expiratory pressure (auto-PEEP) was seen on the flow-volume curves during both two-lung and one-lung ventilation. Eighty-seven percent of the patients whose trachea was intubated with a smaller size (35- and 37-French gauge) double-lumen tracheal tube exhibited auto-PEEP, compared with patients in whom the tube used was larger (39- or 41-French gauge: 54% and 50%, respectively). Before operation, mean airway resistance was significantly greater in patients who exhibited auto-PEEP during anaesthesia (2.4 cm H2O litre-1 s) than in patients without auto-PEEP (1.7 cm H2O litre-1 s).