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Objective Nociceptive Assessment in Ventilated ICU Patients: A Feasibility Study Using Pupillometry and the Nociceptive Flexion Reflex
Published on: July 4, 2018
Association of Hypocalcemia and Mean Arterial Pressure With Patient Outcome in ICU
Fang-Yuan Li1, Yan Chen2, Xiang Zhou3
1Department of Medical Intensive Care Unit, Peking Union Medical College Hospital, Eight-year Program of Clinical Medicine, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
Insights
Hypocalcemia within 24 hours of ICU admission is linked to increased mortality. Blood pressure and its reactivity may mediate this association, offering potential therapeutic targets for improving outcomes.
Area of Science:
- Critical Care Medicine
- Electrolyte Balance
- Clinical Outcomes Research
Background:
- Hypocalcemia is a common electrolyte disturbance in critically ill patients.
- The relationship between early hypocalcemia and mortality in the ICU requires further elucidation.
- Potential mediating roles of hemodynamic parameters in the hypocalcemia-mortality link are not fully understood.
Purpose of the Study:
- To investigate the association between early hypocalcemia (within 24 hours of ICU admission) and ICU mortality.
- To explore the potential mediating effects of blood pressure and blood pressure reactivity on the relationship between ionized calcium (iCa) and mortality.
Main Methods:
- Retrospective observational study including 4947 nonhypercalcemic adult patients admitted to ICUs.
- Patients were grouped based on mean ionized calcium (iCa) levels within the first 24 hours (cutoff 1.1 mmol/L).
- Time-weighted average mean arterial pressure (TWA-MAP) and TWA-MAP/norepinephrine (TWA-MAP/NE) dose were used to assess blood pressure and reactivity.
Main Results:
- Hypocalcemia was present in 43.7% of patients.
- Early hypocalcemia was independently associated with increased ICU mortality (OR, 0.17; 95% CI, 0.04-0.79).
- Blood pressure (TWA-MAP-0) and blood pressure reactivity (TWA-MAP-0/NE) mediated ICU mortality by 4.55% and 2.6%, respectively.
- iCa showed a positive correlation with TWA-MAP (ρ = 0.17, p < 0.01).
Conclusions:
- Early hypocalcemia in nonhypercalcemic ICU patients is an independent predictor of mortality.
- Blood pressure and blood pressure reactivity potentially mediate the association between early iCa levels and ICU mortality.
- A positive association exists between iCa and TWA-MAP, but not between iCa and blood pressure reactivity (TWA-MAP/NE).
Objectives:
We aimed to verify the relationship between hypocalcemia in the first 24 hours of ICU admission and mortality, we also hypothesized that blood pressure and blood pressure reactivity are associated with ionized calcium (iCa) and might have mediation effects in the iCa-mortality association.
Design:
Retrospective, observational study.
Setting:
ICUs in a general hospital.
Patients:
Nonhypercalcemia adult patients were divided into two groups based on mean iCa within the first 24 hours after ICU admission using a cutoff of 1.1 mmol/L.
Interventions:
None.
Measurements And Main Results:
A total of 4947 patients from Peking Union Medical College Hospital between January 2013 and December 2022 were included in the study, with 2160 (43.7%) suffering from hypocalcemia. Overall, the median (interquartile range) age was 61 years (49-71 yr), with 2824 (57.1%) being female. Time-weighted average mean arterial pressure (TWA-MAP) above 0 and 65 mm Hg, respectively, during the first 24 hours were used to analyze the MAP of each patient and TWA-MAP/norepinephrine (TWA-MAP/NE) dose was calculated to examine blood pressure reactivity. Among 4091 patients eligible for multivariate analysis, iCa was independently associated with ICU mortality (odds ratio, 0.17; 95% CI, 0.04-0.79; p < 0.05). Both the blood pressure parameter (TWA-MAP above 0 mm Hg [TWA-MAP-0]) and pressure reactivity parameter (TWA-MAP-0/weight-adjusted dose of norepinephrine infusion in the first 24 hr after ICU admission [TWA-MAP-0/NE]) mediated the outcome of ICU mortality with a proportion of 4.55% (95% CI, 0.16-17%; p < 0.05) and 2.6% (95% CI, 0.02-11%; p < 0.05), respectively. TWA-MAP-0 correlated positively with iCa (Spearman rank test, ρ = 0.17; p < 0.01) while no significant association was found between iCa and TWA-MAP-0/NE (Spearman rank test, ρ = -0.07; p < 0.01).
Conclusions:
In this retrospective study on nonhypercalcemia patients, iCa of the first 24 hours after admission was independently associated with ICU mortality, which was potentially mediated by TWA-MAP and blood pressure reactivity (TWA-MAP/NE). iCa was also positively associated with TWA-MAP, while no general relationship was found between iCa and TWA-MAP/NE.
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