Near-continuous, noninvasive blood pressure monitoring in the out-of-hospital setting.

OBJECTIVES: This study was conducted to test out-of-hospital performance of a noninvasive radial artery tonometry device to assess blood pressure (BP), providing readings every 10-12 seconds. The primary objective was to determine the correlation between noninvasive BPs calculated with radial artery tonometry and standard oscillometric cuff methods. The secondary objective was to determine whether the difference observed between the two techniques was consistent over the range of BPs measured. METHODS: This prospective trial enrolled adults transported by helicopter (n = 9 patients), fixed-wing airplane (n = 1), or ground vehicle (n = 10) of a single transport service. Patients had BP assessed simultaneously, by both standard automatic cuff and radial artery tonometry device, every 5 minutes. Data were assessed with correlation coefficients, and Bland-Altman techniques were utilized to assess for bias over the range of mean arterial pressures (MAPs) encountered. For all tests, p was set at 0.05. RESULTS: No major problem with radial artery tonometry device field performance was noted. There were 139 pairs of MAP assessments in 20 patients. The correlation coefficient for the two assessment modalities was 0.96. Bland-Altman bias plot and Pitman's test (p = 0.11) revealed good correlation between the two assessment mechanisms over the entire range of MAPs (42 to 163 mm Hg) encountered in the study. CONCLUSION: The radial artery tonometry device provided MAP assessments that were highly correlated with readings from a standard oscillometric device. The radial artery tonometry device performed well in a variety of patient types and in multiple transport vehicles, and there was no sign that its performance was adversely affected by the out-of-hospital setting.

Inadequate hemodynamic management in patients undergoing interfacility transfer for suspected aortic dissection.

The study goal was the analysis of effectiveness of hemodynamic management of patients undergoing interfacility transport for suspected acute aortic dissection (SAAD). Our retrospective, consecutive-case review examined 62 nonhypotensive patients transported by an air emergency medical services (EMS) service during 1998 to 2002, with referral hospital diagnosis of SAAD. Of patients with systolic blood pressure (SBP) less than 120 upon air EMS arrival, antihypertensives had been given in only 23/42 (54.8%). In 19 cases where pretransport SBP is less than 120, with no referral hospital antihypertensive therapy given, median pretransport SBP was 158 (range, 122-212). In 20/62 cases (32.3%), the air EMS agency instituted antihypertensive therapy, which was successful; of 42 cases with pretransport SBP less than 120, mean intratransport SBP decrement was 24 (95% confidence interval, 16-32). In patients undergoing transport for SAAD, pretransport hemodynamic therapy was frequently omitted and often inadequate, generating an opportunity for air EMS intervention. Education to improve SAAD care should focus upon both referral hospitals and transport services.

Use of a radial artery compression device for noninvasive, near-continuous blood pressure monitoring in the ED.

This study's goal was to test a novel device using continuous partial radial artery compression for mean arterial pressure (MAP) measurement. A prospective, nonblind, convenience-sample trial at a level I center (annual ED census 70,000) enrolled 15 adults with indwelling radial arterial catheters and accessible contralateral radial pulse. Subjects had MAPs measured simultaneously by test device (TEST assessments), oscillometric brachial artery cuff (OSC), and arterial line (ART). There was no difference between the three groups' MAP means (P = .98). R(2) values for ART/OSC and ART/TEST were 0.96 and 0.95, respectively (P <.001). TEST and OSC MAP readings were equally likely (P = 0.66) to be within 5 mm Hg of ART in both the overall set of 307 MAPs and in the subset of 120 cases in which ART MAPs were below 80 (P = .47). The TEST device performed at least as well as oscillometric assessment, offering advantages of noninvasive, near-continuous data.