Quality Improvement Report: Linking guideline to regular feedback to increase appropriate requests for clinical tests: blood gas analysis in intensive care

Introduction. Reliable results of an arterial blood gas (ABG) analysis are crucial for the implementation of appropriate diagnostics and therapy. We aimed to investigate the differences (Δ) between ABG parameters obtained from point-of-care testing (POCT) and central laboratory (CL) measurements, taking into account the turnaround time (TAT). Materials and methods. A number of 208 paired samples were collected from 54 intensive care unit (ICU) patients. Analyses were performed using Siemens RAPIDPoint 500 Blood Gas System on the samples just after blood retrieval at the ICU and after delivery to the CL. Results. The median TAT was 56 minutes (IQR 39-74). Differences were found for all ABG parameters. Median Δs for acid-base balance ere: ΔpH=0.006 (IQR –0.0070–0.0195), ΔBEef=–0.9 (IQR –2.0–0.4) and HCO3–act=–1.05 (IQR –2.25–0.35). For ventilatory parameters they were: ΔpO2=–8.3 mmHg (IQR –20.9–0.8) and ΔpCO2=–2.2 mmHg (IQR –4.2––0.4). For electrolytes balance the differences were: ΔNa+=1.55 mM/L (IQR 0.10–2.85), ΔK+=–0.120 mM/L (IQR –0.295–0.135) and ΔCl–=1.0 mM/L (IQR –1.0–3.0). Although the Δs might have caused misdiagnosis in 51 samples, Bland-Altman analysis revealed that only for pO2 the difference was of clinical significance (mean: –10.1 mmHg, ±1.96SD –58.5; +38.3). There was an important correlation between TAT and ΔpH (R=0.45, p<0.01) with the safest time delay for proper assessment being less than 39 minutes. Conclusions. Differences between POCT and CL results in ABG analysis may be clinically important and cause misdiagnosis, especially for pO2. POCT should be advised for ABG analysis due to the impact of TAT, which seems to be the most important for the analysis of pH.

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Transcutaneous Po2 Monitoring in Routine Management of Infants and Children With Cardiorespiratory Problems

PEDIATRICS ◽

10.1542/peds.57.5.681 ◽

1976 ◽

Vol 57 (5) ◽

pp. 681-690

Author(s):

R. Huch ◽

A. Huch ◽

M. Albani ◽

M. Gabriel ◽

F. J. Schulte ◽

...

Keyword(s):

Intensive Care ◽

Pediatric Intensive Care ◽

Blood Gas Analysis ◽

Gas Analysis ◽

Blood Gas ◽

Close Correspondence ◽

Arterial Po2 ◽

Transcutaneous Po2 ◽

Made In

Results are reported concerning the clinical application of the transcutaneous Po2 method (tc Po2 method) according to Huch et al. for monitoring arterial Po2. Thirty long-term continuous tc Po2 recordings were made in 22 ventilated children and infants with cardiorespiratory problems in four different pediatric intensive care units (Zürich, Göttingen, Kassel, and Mainz). These recordings were compared with 132 arterial Po2 determinations made during the same period of time. There was a linear relationship and a close correspondence between arterial Po2 and tc Po2 (r = .94). The continuous recordings have shown that the variability of Po2 is much greater than assumed so far by single blood gas analysis. This fact restricts greatly the value of single samples. Continuous tc Po2 monitoring has proved to be a great help in optimal respirator setting.

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Comparing the Liquid Heparin Syringe with Dry Bound Heparin Syringe for Blood Gas Analysis

Journal of Cardiac Critical Care TSS ◽

10.1055/s-0040-1709624 ◽

2019 ◽

Vol 3 (02) ◽

pp. 059-067

Author(s):

Manoj Kumar Sahu ◽

Seshagiribabu Yagani ◽

Dharmraj Singh ◽

Umed Singh ◽

Sarvesh Pal Singh ◽

...

Keyword(s):

Intensive Care ◽

Partial Pressure ◽

Blood Gas Analysis ◽

Gas Analysis ◽

Surgical Patients ◽

Arterial Oxygen ◽

Surgical Intensive Care Unit ◽

Blood Gas ◽

Surgical Intensive Care ◽

Accurate Analysis

Abstract Background Blood gas (BG) analysis is routine today for patient management in intensive care units. Accurate analysis of different parameters in the BG is essential for managing critical patients. Errors in BG analysis can happen at many levels, with one of them being at sampling and heparinization. We compared self-prepared heparinized syringes rinsed with liquid heparin (LH) and the standard commercially available syringes with dry bound heparin (DBH) for arterial BG analysis of postoperative cardiac surgical patients. Methods This prospective observational study was conducted in 100 consecutive adult cardiac surgical patients in the cardiac surgical intensive care unit. Paired samples were collected, analyzed immediately, and statistically compared for pH, partial pressure of arterial oxygen (pO2), partial pressure of arterial carbon dioxide (pCO2), oxyhemoglobin saturation (SaO2), HCO, Na+, K+, Cl–, Ca2+, Mg2+, base excess (BE), hemoglobin (Hb), hematocrit, glucose, and lactate. Paired parameters were compared and agreement was evaluated using Bland–Altman difference plots. The 95% limits of absolute agreement (LOA) were compared with total allowable error (TEa). Results The BG parameters analyzed by two types of heparinized (LH and DBH) syringes were found to be comparable with a negligible mean difference and had an agreement outside the TEa of 8% for pO2, pCO2, and hematocrit, 7% for BE, 6% for Mg2+, 5% for K+, Ca2+, and lactate, 4% for HCOand Na+, 3% for pH, Cl–, Hb, and glucose, and zero for SaO2. The two types of syringes did not show clinically relevant discrepancies among many different parameters as per LOA and TEa limits. Conclusion In this study, we found that the BG parameters—respiratory, metabolic, and electrolytes—were comparable between the two types of syringes used for sampling. Unlike some previous studies, we did not find statistically significant differences among these analytes, which might have been due to appropriate self-preparation of heparin syringes.

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Working accuracy of pulse oximetry in COVID-19 patients stepping down from intensive care: a clinical evaluation

BMJ Open Respiratory Research ◽

10.1136/bmjresp-2020-000778 ◽

2020 ◽

Vol 7 (1) ◽

pp. e000778

Author(s):

Keir Elmslie James Philip ◽

Benjamin Bennett ◽

Silas Fuller ◽

Bradley Lonergan ◽

Charles McFadyen ◽

...

Keyword(s):

Intensive Care ◽

Pulse Oximetry ◽

Blood Gas Analysis ◽

Gas Analysis ◽

Blood Gas ◽

Limits Of Agreement ◽

Arterial Blood Gas ◽

Paired Samples ◽

Arterial Blood ◽

Step Down

IntroductionUK guidelines suggest that pulse oximetry, rather than blood gas sampling, is adequate for monitoring of patients with COVID-19 if CO2 retention is not suspected. However, pulse oximetry has impaired accuracy in certain patient groups, and data are lacking on its accuracy in patients with COVID-19 stepping down from intensive care unit (ICU) to non-ICU settings or being transferred to another ICU.MethodsWe assessed the bias, precision and limits of agreement using 90 paired SpO2 and SaO2 from 30 patients (3 paired samples per patient). To assess the agreement between pulse oximetry (SpO2) and arterial blood gas analysis (SaO2) in patients with COVID-19, deemed clinically stable to step down from an ICU to a non-ICU ward, or be transferred to another ICU. This was done to evaluate whether the guidelines were appropriate for our setting.ResultsMean difference between SaO2 and SpO2 (bias) was 0.4%, with an SD of 2.4 (precision). The limits of agreement between SpO2 and SaO2 were as follows: upper limit of 5.2% (95% CI 6.5% to 4.2%) and lower limit of −4.3% (95% CI −3.4% to −5.7%).ConclusionsIn our setting, pulse oximetry showed a level of agreement with SaO2 measurement that was slightly suboptimal, although within acceptable levels for Food and Drug Authority approval, in people with COVID-19 judged clinically ready to step down from ICU to a non-ICU ward, or who were being transferred to another hospital’s ICU. In such patients, SpO2 should be interpreted with caution. Arterial blood gas assessment of SaO2 may still be clinically indicated.

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Iatrogenic Anaemia in the Critically Ill: A Survey of the Frequency of Blood Testing in a Teaching Hospital Intensive Care Unit

Journal of the Intensive Care Society ◽

10.1177/175114370901000413 ◽

2009 ◽

Vol 10 (4) ◽

pp. 279-281 ◽

Cited By ~ 1

Author(s):

Tim Astles

Keyword(s):

Intensive Care ◽

Critically Ill ◽

Teaching Hospital ◽

Blood Gas Analysis ◽

Gas Analysis ◽

Blood Gas ◽

Arterial Blood Gas ◽

Day Range ◽

Arterial Blood ◽

Blood Gas Analyses

Anaemia in the critically ill remains a contentious issue. Despite adoption of lower haemoglobin levels as transfusion triggers, many patients on intensive care units (ICUs) still require blood transfusions during their illness. One factor that contributes to the critically ill becoming anaemic is regular phlebotomy. Over a two week period, all blood tests performed on patients in a busy, teaching hospital ICU were surveyed to allow calculation of the total volume of blood that had been taken. On average, 52.4 mL of blood was taken per patient per day, and 366.8 mL per patient per week. The most frequently performed tests were arterial blood gas analyses, performed on average 5.8 times per patient per day (range 0–21 times per day). Arterial blood gas analysis alone accounted for taking of 29 mL of blood per patient per day, ie 203 mL per patient per week. Several methods for reducing the amount of blood taken from ICU patients have been identified and discussed. By implementing some of these simple changes in our institution, it would be possible to reduce the volume of blood taken by 43%.

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Blood gas analysis may lead to iatrogenic anaemia in intensive care

Australian Critical Care ◽

10.1016/s1036-7314(00)70615-1 ◽

2000 ◽

Vol 13 (1) ◽

pp. 30 ◽

Cited By ~ 3

Author(s):

M. Greenwood

Keyword(s):

Intensive Care ◽

Blood Gas Analysis ◽

Gas Analysis ◽

Blood Gas

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Unpredictable error in calculated bicarbonate homeostasis during pediatric intensive care: the delusion of fixed pK'.

Clinical Chemistry ◽

10.1093/clinchem/29.1.69 ◽

1983 ◽

Vol 29 (1) ◽

pp. 69-73 ◽

Cited By ~ 13

Author(s):

R C Rosan ◽

D Enlander ◽

J Ellis

Keyword(s):

Intensive Care ◽

Pediatric Patients ◽

Pediatric Intensive Care ◽

Blood Gas Analysis ◽

Gas Analysis ◽

Blood Gas ◽

Hasselbalch Equation

Abstract Bicarbonate balance is usually calculated from indirect total CO2 values determined by blood-gas analysis. Total CO2 is computed from the Henderson-Hasselbalch equation, under the assumption that the pK' is constant or at most varies insignificantly. In pediatric patients in intensive care, we have found instances of large errors in this assumption. We join Natelson and Nobel in asserting that total CO2 should be measured. Little reliance should be placed on bicarbonate estimation.

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