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Tuesday, May 3, 2016

ERRORS THAT CAN HAPPEN WITH THE SAMPLING FOR ARTERIAL BLOOD GAS ANALYSIS AND POSSIBLE CONSEQUENCES


❎AIR BUBBLES IN SYRINGE: may wrongly increase the Pao2 , Sao2 and pH

❎DILUTION OF THE SAMPLE WITH SALINE FLUSH OR HEPARIN: may wrongly increase Pao2 , while it decrease Paco2 , glucose, lactate , potassium and hemoglobin 

❎VENEPUNCURE DURING SAMLE COLLECTION: may wrongly decrease Po2 and So2 while it increases Pco2

❎ CLOTTING OF THE SAMPLE: may wrongly increase the potassium concentration 

#ABGerrors , #abg , #AbgSampling

ERRORS THAT MAY HAPPEN, IF AN ARTERIAL BLOOD GAS SAMPLE IS LEFT FOR SOME TIME, BEFORE ANALYSIS



🔹Reduced pH (anaerobic metabolism)
🔹Reduced PaO2 (utilization of dissolved oxygen)
🔹Raised PaCO2 ( production of CO2 from continued metabolism)
🔹Reduced glucose ( utilization if glucose stores)
🔹Increased lactate( anaerobic metabolism)

#abg , #AbgErrors

CALCULATION OF THE VOLUME OF OXYGEN CYLINDER REQUIRED FOR A TRANSFER


▫️For this, we should know:
     1. Oxygen delivered = FiO2 x Minute Volume 
     2. Duration of the transfer

▫️For e.g. If we are expecting a duration of 2 hours (120 minutes) and we are having Size E cylinders and also need to deliver an FiO2 of 1 @ 6L / min

1. O2 delivered = 1 x 6 = 6L/ min
2. Size E has 660 L of O2, which will suffice for 660/6= 110 minutes ; so for 120 minutes, we need 2 cylinders 

#AnesthesiaGas , #OxygenCylinder


Monday, May 2, 2016

DIPPING IN DOPPLER


🎯The Doppler effect can be explained by considering a series of water-waves travelling out from the centre of a pond, in a circular form

🎯The frequency of the waves is related to the medium and the speed at which they are travelling. 

🎯The frequency of the waves reaching the periphery is less than the frequency nearer the centre. 

🎯If a detector was in the periphery it would detect the frequency of the waves whose frequency will be less

🎯But if the detector then started moving towards the source, the frequency would increase as the detector would be picking the waves nearer to the centre, whose frequency will be more.

🎯The Doppler effect describes the change in frequency of sound waves if the source of sound is moving in relation to the detector. The frequency is increased if the source is moving towards the detector and reduced if it is moving away.

🎯APPLICATIONS OF DOPPLER EFFECT

✔️It allows the confirmation of flow within peripheral arteries as well as in the brain, where the circle of Willis can be scanned.

✔️In echocardiography

✔️in obstetric practice when a fetal heart rate monitor is used

#doppler ,#anesthesia , #usg

Thursday, April 28, 2016

MOBILE PHONES & MEDICAL EQUIPMENTS


🔹Researchers at University of Amsterdam have recorded nearly 50 incidents of electromagnetic interference in hospitals and classified 75% of them as hazardous.

🔹Researchers are of the opinion that mobile phones should not come within 1 meter to hospital beds and equipment 

🔹They are likely to induce errors in the functioning of equipments such as Ventilators , Pacemakers , Syringe pumps etc

🔹They observed that the General Packet Radio Service ( GPRS ) signal generation technology that allows wireless internet access has been particularly associated with the problem 

🔹 More studies are needed to get more clear information about this issue.

#MobilePhoneHazards , #ICUequipments , #MobilephonesHospital





Monday, April 25, 2016

FUROSEMIDE , THIAZIDES & NSAIDs : A FEW FACTS❗️


⚜Furosemide is a loop diuretic

⚜It interferes with the concentrating capacity of the loop of Henle.

⚜It is effective in patients with renal dysfunction, whereas the thiazides are NOT.

⚜It potentiates the nephrotoxic effects of cephalosporins and the ototoxic effects of aminoglycosides.

⚜NSAIDs inhibit renal prostaglandin, causing sodium to be retained, which reduces the diuresis caused by furosemide.

⚜ Furosemide is a venous and arteriolar dilator and thus reduces both preload and afterload in a time frame just before the period of onset of a significant diuresis.



Thursday, April 21, 2016

PERIOPERATIVE CONCERNS IN THE SURGICAL MANAGEMENT OF PATIENTS WITH MOYAMOYA SYNDROME

Moyamoya disease is characterized by bilateral stenosis of the distal portion of the internal carotid artery and the proximal anterior and middle cerebral arteries

There is a compensatory formation of an abnormal network of perforating blood vessels providing collateral circulation. 


Patients are at risk for both hemorrhagic and ischemic stroke. 

On cerebral angiography, in more advanced stages of the disease, the hemispheric perfusion appears as a ‘puff of smoke’, from which the disease derives its name (Moyamoya= Puff of smoke in Japanese).

Usual neurosurgical treatment involves Superficial Temporal Artery to Middle Cerebral Artery (MCA) Anastamosis through a small craniotomy, if there is a suitable MCA target. If not, an encephalo-duro-arterio-synangiosis (EDAS) can be performed by opposing a Superficial Temporal Artery pedicle to the cortical surface; neovascularization occurs over time (months to years).

Excessive hypertension may cause hemorrhage from friable vessels and hypotension may cause ischemic stroke from hypoperfusion

Blood pressure, blood volume, and PaCO2 require careful monitoring because moyamoya patients have a diminished cerebral perfusion reserve and deviation from normal levels can result in stroke.

So we have to take special care to avoid hypotension , hypovolemia ( give optimal preoperative, intraoperative and postoperative hydration) hyperthermia, and hypocarbia ( to avoid hypocarbia induced cerebral vasoconstriction)


Reference 

Surgical Management of Moyamoya Syndrome Edward R. Smith, R. Michael Scott , Skull Base. 2005;15(1):15-26.

Parray T, Martin TW, Siddiqui S. Moyamoya disease: a review of the disease and anesthetic management. J Neurosurg Anesthesiol. 2011 Apr;23(2):100-9. 

Wednesday, April 20, 2016

DEXAMETHASONE AS AN ANTIEMETIC; THINGS TO BE KEPT IN MIND


▫️Dexamethasone is an extremely effective antiemetic for children.

▫️Usually a one-off dose of 4 mg is given. 

▫️This single dose has not been shown to produce significant adverse effects such as immunosuppression and poor wound healing.

▫️Has rescue antiemetic properties

▫️Most effective if given early on in the operation.

▫️An awake patient may complain of an uncomfortable sensation of perineal warmth, when dexamethasone is given

#ponv , #antiemetics , #dexamethasone , #anesthesia , #pharmacology , #CriticalCare

Sunday, April 17, 2016

SUB DURAL HEMATOMA (SDH) FACTS FOR THE ANESTHESIOLOGIST


✔️10–20% of all patients with craniocerebral trauma. 

✔️Blood between the dura mater and arachnoid 

✔️Usually venous bleeding 

✔️A blow to the head puts tension on the cerebral veins, and they typically tear at their attachment to the dural sinuses.

✔️Acute subdural hematomas are an absolute emergency indication 

✔️In 95 % of all cases, the lesion is supratentorial (especially frontoparietal) 

 ✔️Bilateral hematoma is present in 15% of all cases.

 ✔️Imaging Modality of choice: CT

✔️CT findings (Acute subdural hematoma): 

〰Hyperdense crescent-shaped hemorrhage(early acute components can appear hypodense) 
〰Not bounded by sutures 
〰subdural hematoma is concave
〰Significant mass effect: midline displacement 
〰Obstructed flow of CSF, blockage of the interventricular foramen of Monro
〰Reduced demarcation between gray and white matter 
〰Cisterna ambiens obliterated 
〰Usually there is no visible fracture 

✔️Postoperative contralateral rebleeding may occur in response to removal of the tamponade. 

✔️Chronic subdural hematoma: Isodense or hypodense collection of blood in a crescent along the brain 

✔️With isointense hematomas, the midline displacement is often the only detectable sign of a hematoma

✔️The contrast enhancement of the cerebral vessels after IV administration of contrast agent aids in differentiating the hematoma from brain tissue 

✔️Significant mass effect 

✔️MRI is not indicated in an acute subdural hematoma 

✔️In a chronic subdural hematoma, MRI can be used to estimate the age of the lesion 

✔️Anisocoria or suddenly fixed pupils are an alarm signal but a late sign . Patients are often intubated.

✔️Prognosis is usually poor if concomitant administration of drugs such as acetylsalicylic acid and clopidogrel has been there

✔️In the CT, clinician should look for :
Extent • Midline displacement • Size of basal cisterns • Obstructed flow of CSF.

✔️Be careful to avoid missing of bilateral isodense chronic subdural hematomas.

#sdh ,#neurosurgery ,#anesthesiology , #BrainImaging , #CTbrain