Blood pressure measurement in patients with cardiogenic shock: the effect of norepinephrine.

BACKGROUND: Before arterial cannulation for invasive blood pressure monitoring, clinical decision-making depends on non-invasive blood pressure in critically ill patients. Whether non-invasive blood pressure is comparable to invasive measurement is not clearly elucidated. We address this issue as it relates to the use of norepinephrine in patients with cardiogenic shock. METHODS: We analysed invasive and non-invasive blood pressure in 85 patients admitted to the Coronary-Care Unit for cardiogenic shock. We compared initial blood pressure measurement (just after radial artery cannulation) and blood pressure taken during the first 72 hours after admission. Invasive blood pressure was used as the reference method. RESULTS: Initial invasive mean and systolic arterial pressures were in a good agreement with oscillometric blood pressure; mean differences were -0.4 ± 8.8 and +6.1 ± 14.4 mmHg with correlation coefficients of 0.76 and 0.74. Doses of norepinephrine were significant negative determinants of invasive/oscillometric blood pressure differences. The invasive/oscillometric mean arterial pressures and SBP differences were +0.1 ± 3.4 and 7.6 ± 1.6 mmHg in patients treated with nothing or a maximum norepinephrine dose of 0.6 µg/kg/min. However, treatment with very high doses of norepinephrine was associated with a steep rise in mean arterial pressures and SBP invasive/oscillometric differences (-9.5 ± 3.3 and -8.5 ± 5.2 mmHg). In a total of 967 sets of blood pressure measurements, invasive/oscillometric differences were relatively stable across blood pressure categories, with the exception of measurements assessed after very high norepinephrine doses. CONCLUSIONS: Non-invasive BP is a sufficient substitute for invasive measurement in cardiogenic shock patients, with the exception of those receiving very high doses of norepinephrine.

Factors influencing the accuracy of non-invasive blood pressure measurements in patients admitted for cardiogenic shock.

BACKGROUND: Although invasively measured blood pressure (invBP) is regarded as a "gold standard" in critically ill cardiac patients, the non-invasive BP is still widely used, at least at the initiation of medical care. The erroneous interpretation of BP can lead to clinical errors. We therefore investigated the agreement of both methods with respect to some common clinical situation. METHODS: We included 85 patients hospitalized for cardiogenic shock. We measured BP every 6 h for the first 72 h of hospitalization, in all patients. Each set of BP measurements included two invasive (invBP), two auscultatory (auscBP), and two oscillometric (oscBP) BP measurements. InvBP was considered as a gold standard. Mean non-invasive arterial pressure (MAP) was calculated as (diastolic pressure + (pulse pressure ÷ 3)). We used Bland-Altman analysis and we calculated concordance correlation coefficients to assess agreement between different BP methods. RESULTS: We obtained 967 sets of BP measurements. AuscMAP and oscMAP were on average only 0.4 ± 8.2 and 1.8 ± 8.5 mmHg higher than invMAP, respectively. On the other hand, auscSBP and oscSBP were on average - 6.1 ± 11.4 and - 4.1 ± 9.8 mmHg lower than invSBP, respectively. However, the mean differences and variability for systolic and diastolic BP variability were large; the 2 standard deviation differences were ± 24 and 18 mmHg. In hypotension, non-invasive BP tended to be higher than invBP while the opposite was true for high BP values. Clinical conditions associated with hypotension generally worsened the accuracy of non-invasive MAP. CONCLUSIONS: Mean arterial pressure measured non-invasively appears to be in good agreement with invasive MAP in patients admitted for cardiogenic shock. Several clinical associated with hypotension can affect accuracy of non-invasive measurement. Auscultatory and oscillometric measurements had similar accuracy even in patients with arrhythmia.

Access-site bleeding and radial artery occlusion in transradial primary percutaneous coronary intervention: influence of adjunctive antiplatelet therapy.

BACKGROUND: The aim of this study was to evaluate access-site complications in patients with ST-segment elevation myocardial infarction treated with a transradial primary percutaneous coronary intervention relative to three different P2Y12 platelet inhibitors. PATIENTS AND METHODS: We enrolled 334 consecutive patients (76.9% men, age: 59.4±9.1 years) treated by one of the following: clopidogrel (n=118), prasugrel (n=102), and ticagrelor (n=114). The use of the IIb/IIIa inhibitor, abciximab, was left to the operators' discretion. The time needed to achieve patent hemostasis, compression time, and local complications were analyzed. RESULTS: The baseline characteristics were similar in all three P2Y12 platelet inhibitor groups. Abciximab was used in 72 (21.6%) patients. Administration of abciximab was associated with a higher incidence of grade II and III hematomas (23.6 vs. 5.0%, P<0.0001, and 5.6 vs. 1.1%, P=0.041, respectively). Among different platelet P2Y12 receptor inhibitor groups, the incidences of hematomas grade II and III were similar in patients who did (P≥0.14) and did not (P≥0.31) receive abciximab. There were no grade IV or V hematomas in any of the groups. Patent hemostasis was achieved faster (24.5±13.4 vs. 43.5±30.0 min, P<0.0001) and compression time was shorter (113.2±53.6 vs. 217.8±115.5 min, P<0.0001) when abciximab was not used. Radial artery occlusion occurred in one (0.3%) patient. CONCLUSION: After transradial primary percutaneous coronary intervention, early patent hemostasis and short artery compression times were associated with a higher incidence of local hematomas. The incidence of hematomas was dependent on the use of abciximab, but unrelated to the type of P2Y12 inhibitor used. All hematomas were without clinical consequences.