Mortality rates increase dramatically below a systolic blood pressure of 105-mm Hg in septic surgical patients.
Clarke DL., Chipps JA., Sartorius B., Bruce J., Laing GL., Brysiewicz P.
<h4>Background</h4>This study used a prospective surgical database, to investigate the level of systolic blood pressure (SBP) at which the mortality rates begin to increase in septic surgical patients.<h4>Methods</h4>All acute, septic general surgical patients older than 15 years of age admitted between January 2012 and January 2015 were included in these analyses.<h4>Results</h4>Of a total of 6,020 adult surgical patients on the database, 3,053 elective patients, 1,664 nonseptic, 52 duplicates, and 11 patients with missing SBP were excluded to leave a cohort of 1,232 acute, septic surgical patients. The median age (intraquartile range [IQR]): 48 (32 to 62) and roughly 50:50 sex ratio (620 female: 609 male). Most of the patients were African: 988 (80.2%) followed by Asians (128 or 10.4%). More than two-thirds (852 or 69.2%) of the patient cohort underwent some form of surgery, and 152 or 12.3% required intensive care unit (ICU) admission. The median length of ICU stay (IQR) was 2 (1 to 4.5) days. The median length of total hospital stay (IQR) was 4 (2 to 9) days. The median SBP (IQR) on admission was 122 (107 to 138). A total of 167 patients died (13.6%). Those that died did have a significantly lower mean SBP compared with the survivors (116 vs 125, P <. 001). Six of 10 patients (60%) with a SBP less than 70 died. The receiver operating characteristic analysis suggests an optimal SBP cut-off of 111 when predicting mortality (area under the receiver operating characteristic curve: .6 [.551, .65]). This cut-off yields a moderate sensitivity (70%), high positive predictive value (90%) but low specificity, and negative predictive value when predicting mortality. Based on this optimal cut-off, 388 or 31.5% of the patients would be classified as shocked. The inflection curve below with fitted nonlinear curve (95% confidence intervals) clearly shows the upward change in observed mortality frequency at lower systolic and base excess (ie base deficit) values. Shocked patients had a significantly higher frequency of mortality (20% vs 11%, P < .001), a significantly higher median lactate (1.9 vs 1.5, P < .001), and mean base deficit (-2.8 vs -1.0, P = .001). No significant difference in mean age, ICU admission, duration of ICU admission, and total length of hospital stay was observed by shocked status.<h4>Conclusions</h4>Our data suggest that patients who die have a significantly lower SBP and clinically significant hypotension in sepsis with regard to increased mortality risk begins at a level of ∼111-mm Hg. This finding needs to be incorporated into bundles of care for surgical sepsis.