Venous Blood Gas
Venous Blood Gas - Related Videos
09:38
Femoral Arterial and Venous Catheterization for Blood Sampling, Drug Administration and Conscious Blood Pressure and Heart Rate Measurements
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Cited by 53 •
2012
Chronic catheterization of blood vessels in the rat is often required for administration of substances, obtain blood sample over a period of time or for direct conscious blood pressure measurements. Femoral arterial catheterization of the rat and corresponding measurements of blood pressure in the conscious animal will be demonstrated.
01:20
Gas Exchange and Transport
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2019
Gas exchange, the intake of molecular oxygen (O2) from the environment and the outflow of carbon dioxide (CO2) into the environment, is necessary for cellular function. Gas exchange during respiration occurs largely via the movement of gas molecules along pressure gradients. Gas travels from areas of higher partial pressure to areas of lower partial pressure. In mammals, gas exchange occurs in the alveoli of the lungs, which are adjacent to capillaries and share a membrane with them. When the...
08:14
Central Venous Catheter Insertion: Subclavian Vein
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2023
Source: James W Bonz, MD, Emergency Medicine, Yale School of Medicine, New Haven, Connecticut, USA Central venous access is necessary in a multitude of clinical situations for hemodynamic monitoring, medication delivery, and blood sampling. There are three veins in the body that are accessed for central venous cannulation: the internal jugular, the subclavian, and the femoral vein. Central venous access via the subclavian vein has several advantages over other possible locations. The subclavian...
06:08
A Novel Method: Super-selective Adrenal Venous Sampling
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Cited by 44 •
2017
'Super-selective' adrenal venous sampling (ssAVS, also called segmental adrenal venous sampling: sAVS) was performed using a micro-catheter to identify adrenal segment(s) that produce excessive amounts of hormones. The ssAVS technique was described, cases in which adrenal segmental lesion(s) were identified by ssAVS were presented, and the usefulness of ssAVS in future adrenal research was discussed.
10:45
Central Venous Catheter Insertion: Femoral Vein
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2023
Source: James W Bonz, MD, Emergency Medicine, Yale School of Medicine, New Haven, Connecticut, USA Central venous access is necessary in a multitude of clinical situations, including vascular access, vasopressor and caustic medication delivery, central venous pressure monitoring, volume resuscitation, total parental nutrition, hemodialysis, and frequent phlebotomy. There are three veins in the body that are accessed for central venous cannulation: the internal jugular, the subclavian, and the...
FAQs
Venous blood has already passed through tissues, so its oxygen measurement reflects oxygen remaining after tissue exchange rather than oxygen entering the circulation. This makes venous oxygen values unsuitable for precise assessment of oxygenation. The same sampling context remains useful for evaluating acid–base and ventilatory abnormalities when the clinical question does not depend on an exact oxygen measurement.
Tissue exchange alters venous blood before collection, producing values that differ from arterial blood. Carbon dioxide and acid–base measurements therefore need to be interpreted as venous results rather than treated as direct arterial equivalents. This distinction is important when assessing hypercapnia or metabolic disturbances and when deciding whether arterial sampling is needed for additional clarification.
The principal measurements include pH, partial pressure of carbon dioxide, bicarbonate, and, when reported, lactate. Together, these variables provide information about acid–base balance and ventilation, while lactate can add information in metabolic emergencies. Oxygen-related results require more caution because venous oxygen reflects blood after tissue exchange rather than precise oxygenation status.
Arterial sampling is necessary when precise oxygenation assessment is required. A VBG can support evaluation of acid–base disturbances and ventilation, but its oxygen measurement does not provide the same information needed for an exact assessment of oxygenation. The choice therefore depends on the clinical question, particularly whether oxygen status or acid–base and respiratory variables are the priority.
The workflow consists of collecting blood from a vein, submitting the sample for analyzer measurement, and reviewing the reported acid–base and respiratory variables in clinical context. Depending on the analyzer, lactate may also be available. Results can then be used to assess the patient’s metabolic or ventilatory state and to determine whether further arterial testing is required.
Clinicians use venous results when they need a rapid assessment of acid–base disturbances, hypercapnia, or metabolic emergencies without necessarily performing an arterial puncture. The measurements can help characterize the patient’s current metabolic and ventilatory state. They may also support decisions about whether the initial evaluation is sufficient or whether precise arterial oxygenation data must be obtained.
Repeated venous measurements can show whether acid–base or ventilatory variables are changing during management. Comparing results over time may help clinicians assess treatment response in patients with metabolic disturbances, hypercapnia, or metabolic emergencies. This use remains focused on trends in the measured variables, while arterial testing is retained when ongoing decisions require precise oxygenation assessment.