The use of venous blood gas in assessing arterial acid-base and oxygenation status - an analysis of aggregated data from multiple studies evaluating the venous to arterial conversion (v-TAC) method.

BACKGROUND: Several methods exist to reduce the number of arterial blood gases (ABGs). One method, Roche v-TAC, has been evaluated in different patient groups. This paper aggregates data from these studies, in different patient categories using common analysis criteria. RESEARCH DESIGN AND METHODS: We included studies evaluating v-TAC based on paired arterial and peripheral venous blood samples. Bland-Altman analysis compared measured and calculated arterial values of pH, PCO2, and PO2. Subgroup analyses were performed for normal, chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and acute and chronic base deficits. RESULTS: 811 samples from 12 studies were included. Bias and limits of agreement for measured and calculated values: pH 0.001 (-0.029 to 0.031), PCO2 -0.08 (-0.65 to 0.49) kPa, and PO2 0.04 (-1.71 to 1.78) kPa, with similar values for all sub-group analyses. CONCLUSION: These data suggest that v-TAC analysis may have a role in replacing ABGs, avoiding arterial puncture. Substantial data exist in patients with chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and in patients with relatively normal acid-base status, with similar bias and precision across groups and across study data. Limited data exist for patients with acute and chronic base deficits.

A new situation awareness model decreases clinical deterioration in the emergency departments-A controlled intervention study.

BACKGROUND: Studies have suggested that adding subjective parameters to early warning score (EWS) systems might prompt more proactive treatment and positively affect clinical outcomes. Hence, the study aimed to investigate effect of a situation awareness model consisting of objective and subjective parameters on clinical deterioration in adult emergency department (ED) patients. METHODS: This controlled pre-and-post interventional study was carried out in July-December 2016 and November 2017-April 2018. In ED patients ≥ 18 years, we examined if a situation awareness model compared with a conventional EWS system could reduce clinical deterioration. The new model consisted of a regional EWS, combined with skin observation, clinical concern and patients' and relatives' concerns, pain, dyspnea, and team risk assessment. Clinical deterioration was defined as change in vital signs requiring increased observation or physician assessment, that is, increase in early warning score from either 0 or 1 to score ≥2 or an increase from score ≥2 and above. Secondary outcomes were mortality, intensive care unit (ICU) admissions, and readmissions. RESULTS: We included 34 556 patients. Patients with two or more registered EWS were included in the primary analysis (N = 21 839). Using difference-in-difference regression, we found a reduced odds of clinical deterioration of 21% (OR 0.79 95% CI [0.69; 0.90]) in the intervention groups compared with controls. No impact on mortality, ICU, or readmissions was found. CONCLUSION: The situation awareness model reduces odds of clinical deterioration, defined as a clinically relevant increase in EWS, in an unselected adult population of ED patients. However, there was no effect on secondary outcomes.

Consensus on predictors of clinical deterioration in emergency departments: A Delphi process study.

AIM: The study aim was to determine relevance and applicability of generic predictors of clinical deterioration in emergency departments based on consensus among clinicians. METHODS: Thirty-three predictors of clinical deterioration identified from literature were assessed in a modified two-stage Delphi-process. Sixty-eight clinicians (physicians and nurses) participated in the first round and 48 in the second round; all treating hospitalized patients in Danish emergency departments, some with pre-hospital experience. The panel rated the predictors for relevance (relevant marker of clinical deterioration) and applicability (change in clinical presentation over time, generic in nature and possible to detect bedside). They rated their level of agreement on a 9-point Likert scale and were also invited to propose additional generic predictors between the rounds. New predictors suggested by more than one clinician were included in the second round along with non-consensus predictors from the first round. Final decisions of non-consensus predictors after second round were made by a research group and an impartial physician. RESULTS: The Delphi-process resulted in 19 clinically relevant and applicable predictors based on vital signs and parameters (respiratory rate, saturation, dyspnoea, systolic blood pressure, pulse rate, abnormal electrocardiogram, altered mental state and temperature), biochemical tests (serum c-reactive protein, serum bicarbonate, serum lactate, serum pH, serum potassium, glucose, leucocyte counts and serum haemoglobin), objective clinical observations (skin conditions) and subjective clinical observations (pain reported as new or escalating, and relatives' concerns). CONCLUSION: The Delphi-process led to consensus of 19 potential predictors of clinical deterioration widely accepted as relevant and applicable in emergency departments.

Mathematical arterialization of venous blood in emergency medicine patients.

OBJECTIVES: Arterial punctures represent a painful and unpleasant experience. Acid-base and oxygenation status can be assessed from peripheral venous blood, but agreement with arterial values is not always clinically acceptable. This study evaluates a method for mathematically transforming peripheral venous values into arterial values in emergency medicine patients. METHODS: Paired arterial and peripheral venous samples were analysed in groups A (47 patients) and B (101 patients), corresponding to the clinical need for arterial blood sampling (A) and without (B). Venous values were input into the mathematical arterialization method and the values of arterial pH, PCO2 and PO2 were calculated and compared with the measured values. RESULTS: The calculated and measured arterial pH and PCO2 values correlated well with the correlation coefficients (r ) of group A, pH 0.94, PCO2 0.97; group B, pH 0.87, PCO2 0.83; and Bland-Altman limits of agreement well within the limits of acceptable laboratory and clinical performance. The calculated values of arterial PO2 followed a set of predefined rules relating calculated and measured PO2 levels in all cases. The method represents an improvement on the use of venous blood alone where the correlation coefficients were as follows: group A, pH 0.85, PCO2 0.88; group B, pH 0.79, PCO2 0.59; and limits of agreement for PCO2 at the border of (group A) or beyond (group B) acceptable clinical limits. CONCLUSION: Application of the mathematical arterialization method may reduce the pain associated with assessment of acid-base and oxygenation status, maximize the information obtained from peripheral venous blood and allow venous measurements to be presented as more commonly interpreted arterial values.