Gaseous nitric oxide (NO) is a potent selective pulmonary vasodilator. When mixed with O2 for more than 10-15 minutes it forms toxic amounts of nitrogen dioxide (NO!). We describe two techniques to administer 20 parts per million (ppm) during mechanical ventilation. A technique using flows of NO and 02 at low pressure to drive a Siemens Servo 900C ventilator provided a constant inspired concentration of NO. Another technique in which NO was added to the inspiratory limb of a Siemens Servo 900C ventilator driven by high pressure oxygen provided a highly variable concentration (9-53 ppm) of inspired NO.

Changes in thoracic electrical bioimpedance during the cardiac cycle are utilised by the BoMed NCCOM3 monitor to measure cardiac output (COTEs)' The technique provides a continuous noninvasive measurement but it has not been widely accepted. To determine the accuracy of the monitor, we compared its measurement with cardiac output measured by dye dilution (CODnJ during induced hypotension and recovery in 23 dogs. After calibration of the NCCOM3 monitor during a resting state in each dog [mean blood pressure 112 ± 17 (SD), mean CODD 3.22 ± 0.99I1minj, the mean difference (COTEIrCODnJ between paired measurements at the nadir of hypotension (blood pressure 55 ± 24 mmHg) was 0.29 ± 0.47 IImin whose limits of agreement (mean difference ± 2 SD) were + 111.8% and-59.1% of the mean hypotensive CODD (l.1O ± 0.66I1min). Upon recovery from hypotension (mean blood pressue 102 ± 20 mmHg), the mean difference between paired measurements was-0.28 ± 0.66 IImin, whose limits of agreement were + 44.1% and-67.8% of the mean CO DD (2.36 ± 1.01 IImin). The mean difference between the two techniques is too variable and excessive to permit substitution of one technique for the other. These results do not support the accuracy and reliability of the BoMed NCCOM3 cardiac output monitor.

We examined the ability of two transcutaneous devices (Fastrac,

We have built a device for use within the hospital and at home that is designed to warn of circuit disconnection when used in conjunction with continuous positive airway pressure (CPAP) therapy delivered via ventilators or CPAP generating systems. The Royal Children's Hospital CPAP alarm is a compact, battery operated alarm and monitor of circuit pressure. The device includes intrinsic safety features including a safety blow-off valve, a high pressure alarm and design features that make the device practical, safe and easy to use by both trained hospital personnel and home care attendants with limited training.