Article

Severe hyperlactatemia with normal base excess: A quantitative analysis using conventional and Stewart approaches

Servicio de Terapia Intensiva, Sanatorio Otamendi y Miroli, Buenos Aires, Argentina.
Critical care (London, England) (Impact Factor: 4.48). 05/2008; 12(3):R66. DOI: 10.1186/cc6896
Source: PubMed

ABSTRACT

Critically ill patients might present complex acid-base disorders, even when the pH, PCO2, [HCO3-], and base excess ([BE]) levels are normal. Our hypothesis was that the acidifying effect of severe hyperlactatemia is frequently masked by alkalinizing processes that normalize the [BE]. The goal of the present study was therefore to quantify these disorders using both Stewart and conventional approaches.
A total of 1,592 consecutive patients were prospectively evaluated on intensive care unit admission. Patients with severe hyperlactatemia (lactate level > or = 4.0 mmol/l) were grouped according to low or normal [BE] values (<-3 mmol/l or >-3 mmol/l).
Severe hyperlactatemia was present in 168 of the patients (11%). One hundred and thirty-four (80%) patients had low [BE] levels while 34 (20%) patients did not. Shock was more frequently present in the low [BE] group (46% versus 24%, P = 0.02) and chronic obstructive pulmonary disease in the normal [BE] group (38% versus 4%, P < 0.0001). Levels of lactate were slightly higher in patients with low [BE] (6.4 +/- 2.4 mmol/l versus 5.6 +/- 2.1 mmol/l, P = 0.08). According to our study design, the pH, [HCO3-], and strong-ion difference values were lower in patients with low [BE]. Patients with normal [BE] had lower plasma [Cl-] (100 +/- 6 mmol/l versus 107 +/- 5 mmol/l, P < 0.0001) and higher differences between the changes in anion gap and [HCO3-] (5 +/- 6 mmol/l versus 1 +/- 4 mmol/l, P < 0.0001).
Critically ill patients may present severe hyperlactatemia with normal values of pH, [HCO3-], and [BE] as a result of associated hypochloremic alkalosis.

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    • "We hypothesize that in ICU patients with normal pH, coexisting metabolic derangements will often be present but go unnoticed when applying the traditional approach. So far, studies largely report only single (mostly admission) values of ICU patients and do not focus on changes in response to institution of therapy and resolution of illness [13]. Serial measurements from the time of admission to the resuscitation and recovery phases will contribute to a better insight into the mechanisms and kinetics of acid-base derangements in the critically ill [8]. "

    Full-text · Dataset · Sep 2013
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    • "We hypothesize that in ICU patients with normal pH, coexisting metabolic derangements will often be present but go unnoticed when applying the traditional approach. So far, studies largely report only single (mostly admission) values of ICU patients and do not focus on changes in response to institution of therapy and resolution of illness [13]. Serial measurements from the time of admission to the resuscitation and recovery phases will contribute to a better insight into the mechanisms and kinetics of acid-base derangements in the critically ill [8]. "
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    ABSTRACT: This study aimed to describe Stewart parameters in critically ill patients with an apparently normal acid-base state and to determine the incidence of mixed metabolic acid-base disorders in these patients. We conducted a prospective, observational multicenter study of 312 consecutive Dutch intensive care unit patients with normal pH (7.35 ≤ pH ≤ 7.45) on days 3 to 5. Apparent (SIDa) and effective strong ion difference (SIDe) and strong ion gap (SIG) were calculated from 3 consecutive arterial blood samples. Multivariate linear regression analysis was performed to analyze factors potentially associated with levels of SIDa and SIG. A total of 137 patients (44%) were identified with an apparently normal acid-base state (normal pH and -2 < base excess < 2 and 35 < PaCO2 < 45 mm Hg). In this group, SIDa values were 36.6 ± 3.6 mEq/L, resulting from hyperchloremia (109 ± 4.6 mEq/L, sodium-chloride difference 30.0 ± 3.6 mEq/L); SIDe values were 33.5 ± 2.3 mEq/L, resulting from hypoalbuminemia (24.0 ± 6.2 g/L); and SIG values were 3.1 ± 3.1 mEq/L. During admission, base excess increased secondary to a decrease in SIG levels and, subsequently, an increase in SIDa levels. Levels of SIDa were associated with positive cation load, chloride load, and admission SIDa (multivariate r(2) = 0.40, P < .001). Levels of SIG were associated with kidney function, sepsis, and SIG levels at intensive care unit admission (multivariate r(2) = 0.28, P < .001). Intensive care unit patients with an apparently normal acid-base state have an underlying mixed metabolic acid-base disorder characterized by acidifying effects of a low SIDa (caused by hyperchloremia) and high SIG combined with the alkalinizing effect of hypoalbuminemia.
    Full-text · Article · Jul 2013 · Journal of critical care
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    • "Clinical manifestations of severe acidemia include cerebral edema, seizures, diaphragm dysfunction [9], decreased myocardial contractility, pulmonary vasoconstriction and systemic vasodilatation [3,10,11]. Acidemia is a potentially life-threatening condition, and previous studies have described the incidence and mechanisms of acidosis occurring in the ICU [1,12,13]. Surprisingly, however, these studies failed to focus specifically on severe acidemia. Furthermore, despite the fact that severe acidemia reflects a serious underlying disease that should be treated as soon as possible, the treatment of acidemia by itself with the administration of intravenous buffers remains controversial [7,8,14,15]. "
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    ABSTRACT: In this study, we sought describe the incidence and outcomes of severe metabolic or mixed acidemia in critically ill patients as well as the use of sodium bicarbonate therapy to treat these illnesses. We conducted a prospective, observational, multiple-center study. Consecutive patients who presented with severe acidemia, defined herein as plasma pH below 7.20, were screened. The incidence, sodium bicarbonate prescription and outcomes of either metabolic or mixed severe acidemia were analyzed. Among 2, 550 critically ill patients, 200 (8%) presented with severe acidemia, and 155 (6% of the total admissions) met the inclusion criteria. Almost all patients needed mechanical ventilation and vasopressors during their ICU stay, and 20% of them required renal replacement therapy within the first 24 hours of their ICU stay. Severe metabolic or mixed acidemia was associated with a mortality rate of 57% in the ICU. Delay of acidemia recovery as opposed to initial pH value was associated with increased mortality in the ICU. The type of acidemia did not influence the decision to administer sodium bicarbonate. The incidence of severe metabolic or mixed acidemia in critically ill patients was 6% in the present study, and it was associated with a 57% mortality rate in the ICU. In contradistinction with the initial acid-base parameters, the rapidity of acidemia recovery was an independent risk factor for mortality. Sodium bicarbonate prescription was very heterogeneous between ICUs. Further studies assessing specific treatments may be of interest in this population.
    Full-text · Article · Oct 2011 · Critical care (London, England)
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