Articles: intubation.
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Comparative Study
Comparison of end-tidal carbon dioxide, oxygen saturation and clinical signs for the detection of oesophageal intubation.
The reliability of various methods for detecting oesophageal intubation was assessed by means of a single blind study in rats. Both oesophagus and trachea were simultaneously intubated. The presence or absence of various clinical signs was noted during tracheal or oesophageal ventilation and arterial blood gases and end-tidal CO2 were measured. ⋯ Moisture condensation in the tracheal tube (PPV = 1.0) and abdominal distension (PPV = 0.9) were judged to be the least reliable because each had a high false negative rate of 0.3. The most reliable method for the early detection of oesophageal intubation in rats was end-tidal, CO2 (sensitivity 1.0, specificity = 1.0, PPV = 1.0). In addition, end-tidal CO2 when used in conjunction with the four clinical signs improved the reliability of these signs.
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Randomized Controlled Trial Comparative Study Clinical Trial
Pressor and catecholamine response to nasal intubation of the trachea.
The catecholamine and cardiovascular responses to nasal intubation of the trachea with and without laryngoscopy have been compared in 23 patients allocated randomly to each treatment. Arterial pressure, heart rate and plasma concentrations of adrenaline and noradrenaline were measured before and after induction and at 1, 3 and 5 min after intubation of the trachea. There were significant increases in systolic and diastolic pressures after tracheal intubation in both groups. The values at 1 min after intubation were significantly higher in the group undergoing laryngoscopy and intubation compared with the group undergoing blind nasal intubation.
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The extent to which pH values of aspirates from feeding tubes could be used to differentiate between (a) gastric and intestinal placement, and (b) gastric and respiratory placement were determined in a clinical study. The sample consisted of 181 adult subjects, 94 with small-bore nasogastric tubes and 87 with nasointestinal tubes. Data were collected at the time of initial tube placement and again, when possible, after one or two days of tube feedings. ⋯ Findings indicated that pH readings were often effective in differentiating between gastric and intestinal placement (p less than .0001). For example, approximately 81% of the aspirates from nasogastric tubes had pH values ranging from 1 through 4, while almost 88% of the aspirates from nasointestinal tubes had pH values of 6 or greater. Only one aspirate from a tube inadvertently placed in the lung was tested; as expected it had an alkaline pH.