A B S T R A C TFor purposes of quantitation these curves are approximated by a simple hyperbolic function, the parameters of which are evaluated by a least squares fit of the data. The parameter A denotes curve shape such that the higher the value of A, the greater the increase in ventilation for a given decrease in PAO2 and hence the greater the hypoxic drive. Curves are highly reproducible for each subject and curves from different subjects are similar. In 10 normal subjects at resting PAcO2, A = 180.2 +14.5 (SEM). When PACO, is adjusted to levels 5 mm Hg above and below control in six subjects A = 453.4 ±103 and 30.2 ±6.8 respectively. These latter values differed significantly from control (P < 0.05). These changes in curve shape provide a clear graphic description of interaction between hypercapnic and hypoxic ventilatory stimuli. At normal PACo2 the VE-PAO2 curve has an inflection zone located over the same P02 range as the inflection in the oxygenhemoglobin dissociation curve. This indicated that ventilation might be a linear function of arterial oxygen saturation or content. Studies in four subjects have

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Background and Purpose-The Cincinnati Prehospital Stroke Scale (CPSS) is recommended for emergency medical services use in identifying patients with stroke. Data evaluating its performance in the field are limited. We assessed the impact of training and use of the CPSS on the accuracy of paramedics' stroke patient identification and on-scene time. Methods-A 1-hour interactive educational presentation on the use of the CPSS was conducted for paramedics transporting patients to an academic medical center. Patients with stroke/transient ischemic attack (TIA) were identified retrospectively from paramedic records and were compared with the hospital's prospective stroke registry for the year before and after the training. Results-There were 154 patients with suspected stroke/transient ischemic attack identified (56% women, 53% white, 44% black, mean age 67Ϯ16 years). There was no difference in paramedics' use of the CPSS (37.5% versus 23.8%, Pϭ0.123) or accuracy of stroke/TIA patient identification (40.5% versus 38.9%, Pϭ0.859) before and after training. Of responsive patients identified by paramedics as having a stroke/TIA, 57% had an abnormality in at least one CPSS item with no effect on on-scene time (17Ϯ6 minutes with a normal versus 18Ϯ6 minutes with an abnormal CPSS, Pϭ0.492). Those with a final diagnosis of stroke/TIA (nϭ61, 40%) more frequently had at least one abnormal CPSS item (70% versus 30%, Pϭ0.008, sensitivity 0.71, specificity 0.52) with 49% of patients with an abnormality having a discharge diagnosis of stroke/TIA. Conclusions-Paramedic

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