Articles: intubation.
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Comparative Study Clinical Trial Controlled Clinical Trial
Intra-ocular pressure changes during induction of anaesthesia and tracheal intubation. A comparison of thiopentone and propofol followed by vecuronium.
Intra-ocular pressure was measured during induction of anaesthesia with propofol (n = 40) or thiopentone (n = 40) followed by vecuronium to facilitate tracheal intubation which was carried out 3 minutes after the administration of relaxant. The average induction doses were 2.15 and 4.83 mg/kg for propofol and thiopentone, respectively. Half the patients in each group received a supplementary dose of the same induction agent (propofol 1.0 mg/kg or thiopentone 2.0 mg/kg) (corrected) prior to intubation. ⋯ Supplementary doses of induction agents before intubation attenuated the increase in intra-ocular pressure. Propofol was significantly more effective in this respect and this group showed the lowest intra-ocular pressure throughout the study period. However, administration of propofol resulted in a 30% incidence of pain on injection and a decrease in systolic arterial pressure of more than 30% in about half the patients.
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Comparative Study
Pressure support compensation for inspiratory work due to endotracheal tubes and demand continuous positive airway pressure.
We evaluated the use of pressure support to compensate for the added inspiratory work of breathing due to the resistances of endotracheal tubes and a ventilator demand-valve system for continuous positive airway pressure (CPAP). A mechanical model was used to simulate spontaneous breathing at five respiratory rates through 7-mm, 8-mm, and 9-mm endotracheal tubes with and without a ventilator demand CPAP circuit. Added work was measured as the integral of the product of airway pressure and volume during inspiration. ⋯ For each endotracheal tube and VT/TI, a level of pressure support (range, 2 to 20 cm H2O) was found which eliminated added work in the spontaneously breathing subject. This level correlated well with that predicted from the data derived using the mechanical model. We conclude that when adjusting for an endotracheal tube's diameter and VT/TI, pressure support can be used to compensate for the added inspiratory work due to artificial airway resistances.
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Critical care medicine · Mar 1988
Endotracheal tube occlusion associated with the use of heat and moisture exchangers in the intensive care unit.
A heat moisture exchanger (HME) with bacterial filtering capabilities was evaluated over an 8-month period in a total of 170 ICU patients. During this time there were 15 endotracheal tube (ETT) occlusions in 15 patients. Over the ensuing 4 months, cascade humidification was used for 81 patients and only one ETT occlusion occurred (p less than .01). ⋯ Most patients with ETT occlusion required minute volumes greater than 10 L and F10(2) greater than 0.4. We conclude that HMEs do not provide sufficient airway humidification for generalized ICU use. Their role outside of the operating room remains to be determined.
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The haemodynamic response to tracheal intubation was compared in 303 patients in whom anaesthesia was induced with either thiopentone 4 mg/kg, etomidate 0.3 mg/kg or propofol 2.5 mg/kg, with and without fentanyl 2 micrograms/kg. There was after propofol alone a significant decrease in arterial blood pressure, which did not increase above control values after intubation. ⋯ Increases in heart rate occurred with all agents after laryngoscopy. The use of fentanyl resulted in arterial pressures lower than those after the induction agent alone, and in an attenuation, but not abolition of the responses to laryngoscopy and intubation.