Reassessment of the Assumed A-V Oxygen Content Difference in the Shunt Calculation

Costa

et al. 2013

Critical Care Medicine

Section: Discussionsupporting

confidence: 74%

Section: Definitionsmentioning

confidence: 99%

Section: Definitionsmentioning

confidence: 99%

Section: Definitionsmentioning

confidence: 99%

See 2 more Smart Citations

Bedside Estimation of Nonaerated Lung Tissue Using Blood Gas Analysis*

Costa

et al. 2013

Critical Care Medicine

Canad. Anaesth. Soc. J.

“…7 We also assumed the PAoz tO be proportional to Flu2 as we did when estimating A-aDo2. The oxygen saturation, which in this case is not directly measured, was obtained from the homogram for oxygen-haemoglobin dissociation curve (Severinghauz).…”

Section: Shunt ("Clinical Short-cut" Method)mentioning

confidence: 99%

Comparison between a clinical short-cut method and a precise laboratory estimation of intrapulmonary shunt and A-aDo2

Fournier¹,

Major

1981

This study shows the application to 20 patients of a very simple formula to estimate A-aD02 and intrapulmonary shunt, from data commonly available in patients with oxygenation disorders. The values obtained by the "clinical short cut" method and the more sophisticated one are in statistically significant correlation.KEY WORDS: MEASUREMENT TECHNIQUES; LUNG, Shunting.RESPIRATORY INSUFFICIENCY is mainly the consequence of hypoventilation or impairment of the ventilation perfusion-ratio. Hypoventilation by itself is relatively easy to diagnose. On the other hand, impairment of the ventilation-perfusion ratio is more intricate to evaluate. It is seen with an intrapulmonary shunP or imbalance of the alveolo-arterial gradient. These two parameters can be estimated precisely with proper laboratory instrumentation. 2 This apparatus is not generally available to the clinician. However it would certainly be helpful to be able to estimate these two values accurately 3 from clinical data commonly measured. We have tried to find a method of estimation which will give results close to the values which would be obtained by sophisticated laboratory measurements. MATERIAL AND METHODSThe study was conducted on twenty intensive care adult patients who needed respiratory assistance following major surgery or for severe cardiac disease.All these patients had a catbeterisation of the pulmonary artery with a Swan-Ganz catheter. Radial artery puncture was done on each of them for blood gas analysis using an Astrup Radiometer blood analyser. Total haemoglobin was determined by Coleman jr. spectrophotometer. A-aDo2 (Precise Laboratory EstimatioJOFormula: Alveolo-arterial gradient was obtained using the following equation: For Pip2, R and Fin2 determinations, respiratory gases were sampled with 50ml glass syringes, previously washed with mineral oil or lactic acid. The inspiratory gases were sampled directly in the inspiratory tube of the MA-I ventilator with the syringe and expiratory gases were gathered from a five litre bag to insure adequate mixing of the expiratory air. This bag was attached to a three-way directional valve placed in the expiratory tube, before the MA-I manifold, in order to have pure expiratory gases. The few patients who were not intubated were connected to this system through a facial mask. Expiratory minute volume was measured with a Wright spirometer at flow corresponding to normal ventilation for each patient.

Vet Record Case Reports

Seizures and prolonged recovery from general anaesthesia in a horse with guttural pouch mycosis undergoing bilateral arterial coil embolisation

Henze

Wiederkehr

Schwarz

et al. 2022

An 11-year-old Holstein mare was referred after profuse bilateral epistaxis due to fungal plaques. Clinical evaluation was unremarkable except for mild tachycardia. General anaesthesia was induced for coil embolisation of the left internal carotid artery, right external carotid and maxillary arteries. Under anaesthesia, cardiorespiratory stability was ensured, and six coils were deployed under fluoroscopy, whereas three previously deployed coils were found. During recovery from anaesthesia, generalised seizures, fast horizontal nystagmus and a breath-holding breathing pattern were evident. Diazepam and medetomidine were administered, but the seizures resumed shortly after. After the administration of hypertonic saline solution and hydrocortisone, the seizures ceased. However, the horse remained unresponsive for 3 hours despite supportive care consisting of oxygen, glucose, fluid therapy and warming. Although a poor prognosis was presumed, the horse recovered after one attempt, 180 minutes after isoflurane cessation. The present case report highlights the importance of adequate support during recovery from anaesthesia.