Biomedical subjects
S W Mentis
Publications and source records attributed to S W Mentis.
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.
The human immunodeficiency virus: knowledge and precautions among anesthesiology personnel.
STUDY OBJECTIVE: To compare actual infectious disease precautions with current recommendations and to determine the influence of age, clinical experience, human immunodeficiency virus (HIV) knowledge, previous personal HIV exposure, and education on practices. DESIGN: Direct clinical observations of infectious precautions and preeducation and posteducation surveys of clinical practices and general knowledge of the HIV. SETTING: University teaching hospital. PARTICIPANTS: Forty-six anesthesia department members completed a preeducation survey, and 24 completed a posteducation survey. MEASUREMENTS AND MAIN RESULTS: The survey showed that adequate precautions were used during less than 50% of the routine procedures. Significant positive correlations were found between years of clinical practice and precautions used while inserting vascular catheters. Significant positive correlation was found between years of clinical practice and precautions taken while handling soiled laryngoscopes. Knowledge about the HIV and HIV transmission was limited. We noted a negative correlation between knowledge and precautions during vascular cannulation procedures, emergency department resuscitation, and tracheal suction. More precautions were taken with patients who had proven HIV infections and those at high risk of infection. The posteducation survey demonstrated a significant increase only in the use of gloves during routine procedures. Knowledge scores were only slightly improved and did not significantly reflect infection control practices. CONCLUSIONS: Adequate infectious disease precautions were not taken by anesthesia personnel. An HIV educational program resulted in only a small increase in precautionary measures.