Characterization of non-cardiac arrest PulsePoint activations in public and private settings

BACKGROUND

Geospatial smartphone application alert systems are used in some communities to crowdsource community response for out-of-hospital cardiac arrest (OHCA). Although the clinical focus of this strategy is OHCA, dispatch identification of OHCA is imperfect so that activation may occur for the non-arrest patient. The frequency and clinical profile of such non-arrest patients has not been well-investigated.

METHODS

We undertook a prospective 3-year cohort investigation of patients for whom a smartphone geospatial application was activated for suspected OHCA in four United States communities (total population ~1 million). The current investigation evaluates those patients with an activation for suspected OHCA who did not experience cardiac arrest. The volunteer response cohort included off-duty, volunteer public safety personnel (verified responders) notified regardless of location (public or private) and laypersons notified to public locations. The study linked the smartphone application information with the EMS records to report the frequency, condition type, and EMS treatment for these non-arrest patients.

RESULTS

Of 1779 calls where volunteers were activated, 756 had suffered OHCA, resulting in 1023 non-arrest patients for study evaluation. The most common EMS assessments were syncope (15.9%, n=163), altered mental status (15.5%, n=159), seizure (14.3%, n=146), overdose (13.0%, n=133), and choking (10.5%, n=107). The assessment distribution was similar for private and public locations. Overall, the most common EMS interventions included placement of an intravenous line (43.1%, n=441), 12-Lead ECG(27.9%, n=285), naloxone treatment (9.8%, n=100), airway or ventilation assistance (8.7%, n=89), and oxygen administration (6.6%, n=68).

CONCLUSIONS

More than half of patients activated for suspected OHCA had conditions other than cardiac arrest. A subset of these conditions may benefit from earlier care that could be provided by both layperson and public safety volunteers if they were appropriately trained and equipped.

Ciprofloxacin and sparfloxacin penetration into human brain tissue and their activity as antagonists of GABAA receptor of rat vagus nerve

Patients undergoing elective surgery for removal of brain tumors, aneurysms, or other vascular malformations were administered a single oral dose of sparfloxacin (400 mg; 16 patients) or ciprofloxacin (750 mg; 5 patients) either 3 to 5 h or 22 to 26 h before surgery. Serum samples were taken from all patients at 0, 1, 3 to 5, 7 to 9, and 22 to 26 h after dosing; an additional serum sample was obtained at 48 h from patients who received sparfloxacin. A single sample of brain tissue was taken from all patients; a sample of cerebrospinal fluid (CSF) uncontaminated with blood was obtained from five patients. Serum and brain tissue samples were assayed by high-pressure liquid chromatography. Drug concentrations in brain tissue exceeded those in CSF by 1.8- to 19.4-fold. Kinetic modeling suggested that peak sparfloxacin concentrations in brain tissue may have occurred later than 3 to 5 h and that actual peak concentrations may therefore have been higher (up to 10 micrograms/g of tissue). The activities of ciprofloxacin and sparfloxacin as antagonists of the gamma-aminobutyric acid antagonist (GABAA) receptor were measured with the rat vagus nerve preparation. The 50% inhibitory concentration (IC50) of ciprofloxacin was 250 microM (95.25 micrograms/ml), but in the presence of biphenyl acetic acid (BPAA), the IC50 of ciprofloxacin was only 0.6 microM (0.23 microgram/ml). In contrast, the IC50 of sparfloxacin alone or in the presence of BPAA was > 300 microM (> 100 micrograms/ml). We conclude that the concentrations of ciprofloxacin and sparfloxacin in brain tissue may exceed serum drug concentrations and cannot be predicted from the concentrations in CSF. Sparfloxacin does not have any activity as a GABA antagonist, either alone or in the presence of BPAA, at the concentrations which are likely to be reached in human brain tissue.