Acidemia Detected on Venous Blood Gas After Out-of-Hospital Cardiac Arrest Predicts Likelihood to Survive to Hospital Discharge

Prognosis of patients with extreme acidosis on admission to the emergency department: A retrospective cohort study

AIM OF THE STUDY

The development of acidosis in critically ill patients is considered to be a negative prognostic factor, and when extreme, even incompatible with life. We aimed to test the prognosis of patients with a pH lower than 6.9 on emergency department admission.

METHODS

A retrospective cohort study in adult patients admitted to two emergency departments with a pH < 6.9 during the first 12 h of admission. Primary outcome was mortality within 24 h from emergency department admission. We performed a regression analysis of clinical and laboratory data in order to identify factors associated with mortality in this population.

RESULTS

We analyzed data of 206 admissions to the emergency departments between 2008 and 2018 with extreme acidosis. pH Values ranged from 6.898 to 6.35 (mean 6.8 and median 6.83). 60 (29%) of the patients survived the first 24 h. 35 patients (58%) of those also survived to hospital discharge, and of them 80% have returned to their previous functional status. Patient's age, type of acidosis, cardio-pulmonary resuscitation on arrival, and diagnosis on admission were correlated with survival.

CONCLUSIONS

A small but significant portion of patients with extreme acidosis on emergency department admission survive at least to 24 h and until hospital discharge. The clinical decision making should be based on other prognostic factors rather than pH value by itself.

Decompensated metabolic acidosis in the emergency department: Epidemiology, sodium bicarbonate therapy, and clinical outcomes

Objective

This article aims to describe the epidemiology of decompensated metabolic acidosis, the characteristics of sodium bicarbonate (SB) administration and outcomes in emergency department (ED) patients.

Design

This is a retrospective cohort study.

Setting

ED of a tertiary referral hospital in Melbourne, Australia.

Participants

Adult patients presenting to the ED between 1 July 2011 and 20 September 2020 with decompensated metabolic acidosis diagnosed on arterial blood gas (ABG).

Main outcome measures

We compared characteristics between those treated with or without SB. We studied SB administration characteristics, change in laboratory variables, factors associated with use and dose, and clinical outcomes.

Results

Among 753,613 ED patients, 314 had decompensated metabolic acidosis on ABG, with 17.8% receiving SB. Patients in the SB group had lower median pH, CO2, bicarbonate, and base excess (BE) levels compared with the No SB group (P < 0.01). The median number of SB doses in the SB group was one treatment. This was given at a median total dose of 100 mmol and at a median of 2.8 h after the diagnostic blood gas results. Only 42% of patients in the SB group had a subsequent blood gas measured. In such patients, there was no significant change in pH, bicarbonate, or BE. SB therapy was not independently associated with mortality.

Conclusions

ABG-confirmed decompensated metabolic acidosis was rare but associated with a high mortality. SB administration occurred in a minority of patients and in more acidaemic patients. However, SB dose was stereotypical and not tailored to acidosis severity. Assessment of SB effect was infrequent and showed no correction of acidosis. Systematic studies of titrated SB therapy are required to inform current practice.

Initial Blood pH, Lactate and Base Deficit Add No Value to Peri-Arrest Factors in Prognostication of Neurological Outcome After Out-of-Hospital Cardiac Arrest

Background: In cardiac arrest survivors, metabolic parameters [pH value, lactate concentration, and base deficit (BD)] are routinely added to peri-arrest factors (including age, sex, bystander cardiopulmonary resuscitation, shockable first rhythm, resuscitation duration, adrenaline dose) to enhance early outcome prediction. However, the additional value of this strategy remains unclear.

Methods: We used our resuscitation database to screen all patients ≥18 years who had suffered in- or out-of-hospital cardiac arrest (IHCA, OHCA) between January 1st, 2005 and May 1st, 2019. Patients with incomplete data, without return of spontaneous circulation or treatment with sodium bicarbonate were excluded. To analyse the added value of metabolic parameters to prognosticate neurological function, we built three models using logistic regression. These models included: (1) Peri-arrest factors only, (2) peri-arrest factors plus metabolic parameters and (3) metabolic parameters only. Receiver operating characteristics curves regarding 30-day good neurological function (Cerebral Performance Category 1-2) were analysed.

Results: A total of 2,317 patients (OHCA: n = 1842) were included. In patients with OHCA, model 1 and 2 had comparable predictive value. Model 3 was inferior compared to model 1. In IHCA patients, model 2 performed best, whereas both metabolic (model 3) and peri-arrest factors (model 1) demonstrated similar power. PH, lactate and BD had interchangeable areas under the curve in both IHCA and OHCA.

Conclusion: Although metabolic parameters may play a role in IHCA, no additional value in the prediction of good neurological outcome could be found in patients with OHCA. This highlights the importance of accurate anamnesis especially in patients with OHCA.