The accuracy and precision of transcutaneous pressure measurements of oxygen (Ptc,O2) and carbon dioxide (Ptc,CO2) in the monitoring of nocturnal assisted ventilation in adult patients were evaluated. Transcutaneous measurements obtained with two analysers, Radiometer TINA‐TCM3 (R) and Kontron MicroGas‐7650 (K), were compared with arterial blood gases analysed in blood samples withdrawn simultaneously in 10 patients. Sensors were heated to 43°C. Measurements of trascutaneous blood gases and arterial blood gases were collected six times at 1‐h intervals. The data obtained with both instruments were similar and did not significantly change over the 5 h test period. Measurement of Ptc,O2 underestimated arterial oxygen tension (Pa,O2) and this underestimation increased with the level of Pa,O2 (p<0.01). Measurements of Ptc,CO2 overestimated arterial carbon dioxide tension (Pa,CO2) and this overestimation increased with the level of Pa,CO2 (p<0.05). These errors suggested an instrumental bias. Mathematical correction of this bias neutralized the error in accuracy and improved the precision ( sd of the differences transcutaneous blood gases ‐ arterial blood gases). An additional correction, suppressing the between‐subject scattering, improved the actual precision: precision was reduced from 1.9 to 0.8 kPa (14.4 to 5.7 mmHg) (R) and from 1.7 to 0.5 kPa (13.1 to 3.7 mmHg) (K) for oxygen, and from 1.0 kPa (7.8 mmHg) (R) and 0.7 kPa (5.6 mmHg) (K) to 0.4 kPa (3.2 mmHg) for carbon dioxide (R and K). In conclusion, with these two successive corrections, transcutaneous oxygen and carbon dioxide provide a reliable estimation of blood gases to monitor nocturnal ventilation in adults with chronic respiratory failure.

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Fifty patients anaesthetized with nitrous oxide-oxygen, supplemented by thiopentone and pethidine, thiopentone and halothane, or droperidol and fentanyl, who received tubocurarine for the maintenance of muscular relaxation were divided into five groups each of ten. At the end of anaesthesia, the patients of groups A and B received intravenously atropine 6 /ig/kg and neostigmine 20 yug/kg, those in groups C and D atropine 12 /fg/kg and neostigmine 40 /ig/kg, and those in group E atropine 8 /ig/kg and neostigmine 20 /ig/kg. In groups A and C atropine was injected in 60 seconds and was followed 1 minute later by neostigmine also administered in 60 seconds. In groups B, D, and E atropine and neostigmine were injected together in 60 seconds. Reversal of residual neuromuscular block was achieved in all five groups without the development of any serious arrhythmias. Statistically significant tachycardia developed only in those groups (A and C) in which atropine was injected 2 minutes before the administration of neostigmine. Of the different dosages and sequences of administration investigated, the combined injection of atropine 6 /*g/kg and neostigmine 20 /tg/kg over 60 seconds appears to be most suitable for the reversal of residual neuromuscular block.