Biomedical subjects

L S Nolan

Publications and source records attributed to L S Nolan.

3 recordsLinked to original sources

PubMed1982

Sequential perioperative lactate determination. Physiological and clinical implications.

Sequential arterial blood lactate concentrations were determined pre-, intra-, and postoperatively in 12 high risk surgical patients. These levels were correlated with simultaneous measurements of arterial blood pressure, cardiac index (CI), and oxygen consumption (VO2). There was a marked increase in lactate values intraoperatively. This increase did not correspond to decreases in either mean arterial pressure (MAP) or CI, but did appear to correlate with decreased intraoperative VO2. Postoperatively, lactate levels remained elevated, and this elevation appeared to correlate with an estimation of intraoperative oxygen deficit. CI and VO2 were increased postoperatively; the data support the hypothesis that these postoperative increases in CI and VO2 represent physiological compensations for intraoperative oxygen deficits. Clinically, determinations of lactate values may prove useful in titrating postoperative therapy to support needed physiological compensations.

Adult↗

PubMed1982

Transcutaneous O2 and CO2 monitoring of high risk surgical patients during the perioperative period.

The usefulness of noninvasive transcutaneous oxygen (PtcO2) and carbon dioxide (PtcCO2) sensors as well as invasive monitoring of flow and oxygen transport were evaluated in the perioperative period of a small series of high risk surgical patients. We used the pattern of physiological events preceding intraoperative death as the criteria for evaluation of the relative usefulness of these variables. Cardiac output (CO), oxygen delivery (DO2), and O2 consumption (VO2) provided the earliest warning of impending circulatory deterioration and were most useful during critical nonlethal circulatory episodes; these were closely paralleled by the PtcO2 index (PtcO2/PaO2); the PtcCO2 was less sensitive. Heart rate (HR) and mean arterial pressure (MAP) were highly variable with frequent changes unrelated to change in flow and O2 transport.

Carbon Dioxide↗

PubMed1981

Transcutaneous PCO2 monitoring on adult patients in the ICU and the operating room.

Studies were performed on 44 patients who were monitored continuously with transcutaneous carbon dioxide (PtcCO2) sensors. The patients were monitored intermittently with arterial and mixed venous blood gases and full hemodynamic and oxygen transport data. Twenty of the studies were performed intraoperatively. A total of 411 data sets revealed a correlation coefficient, r, between arterial and transcutaneous PCO2 of 0.80 when the patients were not in low flow shock, i.e., cardiac index (CI) greater than 1.5 L/min x M2. On the basis of these data, the authors have found the normal arterial-transcutaneous carbon dioxide gradient, delta CO2, (delta CO2 = PtcCO2 -- PaCO2) to be 23 +/- 11 torr. The PtcCO2 monitor was found to be a valuable trend monitor of arterial CO2 tensions of adults during adequate cardiac function in the ICU and the operating room. Twenty-four data sets were collected while 3 patients were monitored during severe shock (CI less than 1.5 L/min x M2). PtcCO2 trended inversely with changes in CI during shock and did not follow PaCO2 (r = --0.85). During shock, delta CO2 = 61 %/- 25 torr. The severity of shock could be roughly determined by comparing the PtcCO2 values with arterial CO2 tensions.

Adult↗