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Biomedical subjects

D N Thrush

Publications and source records attributed to D N Thrush.

22 records · Page 2Linked to original sources
PubMed1992

Incidence of arterial oxygen desaturation in cardiac patients premedicated with intramuscular scopolamine and morphine.

The effect of a standard preoperative medication combination, morphine and scopolamine, on arterial oxyhemoglobin saturation was measured continuously in 29 patients scheduled for elective coronary artery bypass grafting procedures. On the morning of operation, both before and after administration of preoperative medication, each patient was monitored continuously with a pulse oximeter (SpO2). Patients received 0.05 to 0.11 mg/kg of morphine (mean = 6.0 +/- 2.1 mg) intramuscularly (IM) and 0.2 to 0.4 mg of scopolamine (mean = 0.30 +/- 0.07 mg) IM. The mean arterial blood oxyhemoglobin saturation decreased from 92.0 +/- 1.8% before preoperative medication to 89.0 +/- 3.8% (P greater than .001) after preoperative medication. Forty-five percent of the patients had SpO2 less than 90% for at least 2 minutes, and 21% below 85%. In conclusion, significant arterial oxyhemoglobin desaturation occurred in this group of cardiac surgical patients after preoperative medication with morphine and scopolamine. Prophylactic administration of oxygen with preoperative medication might reduce the incidence of hypoxemia in this group of patients at risk for myocardial ischemia.

Aged↗
PubMedDate not supplied

Weaning with end-tidal CO2 and pulse oximetry.

STUDY OBJECTIVE: To determine whether continuous measurement of arterial oxyhemoglobin saturation (SpO2) and end-tidal carbon dioxide (P(ET)CO2) can be used to wean patients safely and efficiently from postoperative mechanical ventilation after cardiac surgery. DESIGN: Prospective study comparing SpO2 and P(ET)CO2 to calculated arterial oxygen saturation (SaO2) and arterial carbon dioxide tension (PaCO2) obtained from blood gas analysis. SETTING: Cardiac surgical intensive care unit at a university-affiliated hospital. PATIENTS: Ten patients requiring elective coronary artery bypass grafting (CABG) were studied in the postoperative period during weaning from mechanical ventilation. INTERVENTIONS: Continuous monitoring of SpO2 and P(ET)CO2 was used to wean patients from mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: The patients were weaned from mechanical ventilation in an average time of 6.5 +/- 1.5 hours (mean +/- SD). A plot of SaO2 versus SpO2 indicated a high correlation (r = 0.84) with sensitivity (100%) for hypoxemia (SaO2 less than 90%). P(ET)CO2 was a good indicator of PaCO2 (r = 0.76); its sensitivity to detect hypercarbia (PaCO2 less than 45 mmHg) was 95%. The gradient between SpO2 and SaO2 was not significantly affected by the weaning process, but the PaCO2-P(ET)CO2 gradient decreased significantly as the ventilator rate was decreased (p less than 0.001). The weaning process was discontinued on four separate occasions because of metabolic acidosis. Ninety-five percent of arterial blood samples confirmed the weaning recommendations based on the continuous monitoring of SpO2 and P(ET)CO2. CONCLUSIONS: Continuous monitorin of SpO2 and P(ET)CO2 can be used to wean patients safely and effectively after CABG when adjustment of minute ventilation compensates for an increased PaCO2-P(ET)CO2 gradient during controlled ventilation.

Carbon Dioxide↗
PubMedDate not supplied

Are automated anesthesia records better?

STUDY OBJECTIVE: To determine whether data recorded by an information management system is significantly different from that recorded manually. DESIGN: A comparison was made between 13 handwritten and 13 computer-generated anesthesia records by calculating the frequency with which recorded variables were outside predetermined acceptable ranges. Five physiologic variables [systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), end-tidal partial pressure of carbon dioxide (PETCO2), and oxygen saturation by pulse oximeter (SpO2)] were compared during the initial 1 1/2 hours of operation. SETTING: Surgical suite at a university-affiliated hospital. PATIENTS: Thirteen adult patients scheduled for operations that required general anesthesia for longer than 1 1/2 hours. INTERVENTION: In addition to the traditional handwritten anesthesia records, an information management system (ARKIVE Patient Management System, DIATEK, San Diego, CA) was used to collect data from each case. MEASUREMENTS AND MAIN RESULTS: No significant differences were found between the methods in the frequency of elevated SBP, elevated DBP, and tachycardia. However, the manual records showed low SBP, DBP, and HR with a significantly lower frequency (2%, 11%, 1%, respectively) than the automated records (6%, 26%, 5%, respectively; p < 0.01). The automated PETCO2 readings were higher than the upper limit (40 mmHg) with a higher frequency (18%) than the manual records (3%; p < 0.01). On the automated records, SpO2 was noted to be 90% or less on two occasions, but significant desaturation was noted only once on the manual charts. CONCLUSIONS: Observer bias, missed readings, and errors of memory, which affect manual anesthetic records, may cause significant inaccuracy and may be avoided by using automated records generated by information management systems.

Anesthesia, General↗