Partial exchange transfusion with 8.5% pyridoxylated polyhemoglobin solution [PolyHb-PPa] was performed in five male chimpanzees weighing 22-30 kg. Serial blood and urine samples were obtained for 3 days. Percutaneous liver biopsies were performed on the 3rd to 4th, and the 9th to 11th days after PolyHb-PPa administration. Mean exchange volume was 42.5 +/- 10.7 ml/kg BW (26.8-54.6 ml/kg), mean Hb dose 3.7 +/- 0.9 g PolyHb-PPa/kg BW (2.4-4.8 g/kg), mean exchange rate 56.7 +/- 7.1% (48.2-67.4%). All animals survived long-term. Analysis of the plasma Hb concentration-time data showed a first order decline at a plasma level of 3.7 +/- 0.9 g PolyHb-PPa/kg BW. Mean intravascular half-life was 14.6 +/- 3.2 h. Total renal elimination of PolyHb-PPa was about 7%. PolyHb-PPa was absorbed and stored by Kupffer cells and transformed into hemosiderin. Siderosis of Kupffer cells and renal tubules had largely subsided 10 days after PolyHb-PPa indicating subsequent in vivo degradation and metabolization of the polymerized Hb fractions.
The aim of our retrospective study was to evaluate the efficacy of routine pulse oximetry and capnometry for detection of oesophageal tube misplacement. Patients undergoing ENT interventions at our hospital are routinely monitored by ECG, arterial blood pressure by cuff, capnography, and pulse oximetry. Beat-to-beat values of Sao2 and CO2 waveform were recorded by a graphic printer connected to a microcomputer, ASA I patients were routinely preventilated with FIO2 = 0.3, and ASA II-III patients with FIO2 = 1.0. Anaesthesia was performed by junior anaesthesiologists under the close supervision of a resident. During a 16-month period, 1372 patients were anaesthetized. The records of 21 patients with accidental oesophageal tube misplacement were available for retrospective evaluation. Nine patients were preventilated with FIO2 = 0.3 (ASA I), 12 patients with FIO2 = 1.0 (ASA II-III). Rapid detection of oesophageal tube position as early as the first ventilation is possible by capnometry, because of the highly significant difference in end-tidal CO2 (0.2 +/- 0.2 vol%; tracheal intubation: 3.7 +/- 0.9 vol.%; P less than 0.0001). The present advanced pulse oximetry method does not permit differentiation between oesophageal and tracheal tube position within 30 s in patients preventilated with FIO2 = 1.0. Oesophageal misplacement was detectable within 7.5 +/- 0.9 s in patients preventilated with FIO2 = 0.3 due to a 2.1 +/- 0.8% decrease in Sao2 (P less than 0.001). Our results underscore the significance of capnometry for rapid detection of inadvertent oesophageal intubation. High-resolution pulse oximetry is a valuable supplement but not a substitute for capnometry.
We continuously monitored spontaneous respiration after extubation by end-tidal CO2 tension (PETCO2) in 19 patients aged 20 to 72 years who had undergone major operations. The respiratory gas was sampled from the nasopharynx via a special nasal catheter and analyzed by a side-stream analyzer. In each case, optimal placement of the nasal catheter was determined by CO2 waveform and the capnograms were recorded for waveform analysis and trend monitoring. PETCO2 was compared with arterial CO2 tension (PaCO2) two to four times during the 2- to 19-hour observation periods by simultaneous measurements. For 65 simultaneous measurements, mean PETCO2 was 38.9 +/- 5.7 mm Hg (range, 26.3 to 48.3 mm Hg) and mean PaCO2 was 38.9 +/- 5.7 mm Hg (range, 26.8 to 46.0 mm Hg; r = 0.82; p less than 0.01). While the mean values for PETCO2 and PaCO2 were similar, several patients had large differences for PaCO2 to PETCO2. The differences of the individual patients did not differ significantly between the various times of measurement. We conclude that this form of capnometry is well suited for continuous, noninvasive monitoring of respiration in nonintubated, spontaneously breathing patients.
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