Pages

Monday, September 19, 2016

A FEW FACTS ABOUT THE ADJUSTABLE PRESSURE LIMITING (APL) VALVE [📖]

🔗 When fully opened the APL valve maintains a pressure of around 1.5 cm of H2O 

🔗 As we close the APL valve, the pressure builds up inside and there is a safety overpressure release valve is incorporated in modern APL valves, to avoid this rising to dangerous levels. This system starts opening at  a pressure of 30 cm of H2O and fully opens at 60 cm of H2O and at this point, allows the gases to escape at a rate of 50L/ min 

🔗 When the patient inspires, the APL valve , if intact, should not allow entrainment of air from the environment 

🔗As the modern reservoir bags are less compliant, compared to the older latex ones, the importance of overpressure relief valves has increased

🔗 As the APL valve will always produce a small resistance to expiration, even when maximally loosened, it helps to maintain PEEP

#Anesthesia , #Anaesthesia

AMNIOTIC FLUID EMBOLISM (AFE) : WHICH ARE THE CONSISTENT CLINICAL FEATURES @ PRESENTATION❓

🎯 Hypotension , Hypoxemia and DIC are hallmarks (Ⓜ️NEMO> "AFE is Highly Dangerous")

🎯 Hypotension & Fetal Distress occur in 100% of cases

🎯 DIC occur in 83% and indicate a bad prognosis 

🎯 Cardiac arrest occur in around 87% of patients

🎯 Mortality is >60% ; it has been observed that only 15% survive with intact neurological function 

🎯 Pulmonary Hypertension, CHF and DIC are key events in the pathogenesis

🎯 Pulmonary edema (occur in >90% of cases),Dyspnoea (occur in 49%) & Bronchospasm (occur in 15%) are the respiratory signs

Reference: Dedhia JD, Mushambi M. Amniotic fluid embolism. Contin Educ Anaesth Crit Care Pain. 2007; 7(5): 152–156. Gist RS, Stafford IP, Leibowitz AB et al. Amniotic fluid embolism. Anaesth Analg. 108(5): 1599–1602.


Wednesday, September 14, 2016

EXAMPLES OF 'SMALL' THINGS WHICH CAN SIGNIFICANTLY IMPAIR PATIENT'S SATISFACTION

The Risk Factors as per EuroSCORE II System used for risk stratification of patients undergoing Cardiac Surgery


📊Patient factors 

• Sex: Female 
• Age: >60 years 
• Co-morbidities including renal, neurological and extra-cardiac arterial disease 

📊Disease factors 

• Recent MI 
• Left ventricular dysfunction 
• Unstable angina 

📊Operative factors 

• Redo or emergency surgery 
• Non-isolated coronary artery bypass grafting


EPIDURAL NEEDLE & CATHETER : KNOW THE MEASUREMENTS

📐 The adult needle is 10 cms long ( shaft measures 8 cms ). 15 cms long needles are also available for obese patients 

📐 The markings are 1 cm apart for the adult needle and 0.5 cm for the pediatric one

📐 For the adult 16 & 18 G are the commonly used ones, whereas for the pediatric 19 G needles are available 

📐 Touhy is the commonly used needle

📐 Regarding the tip: ✔️The bevel is angled at 20 degree with the shaft ✔️ It is known as Huber point ✔️ It's blunt ✔️ All these features aid in the effectiveness of Loss of Resistance Technique 

📐 Regarding the catheter: ✔️ It's made of nylon or teflon ✔️ The distal tip is rounded and closed ✔️So fluid can escape only through the side ports. All these features helps to reduce chances of dural puncture and vascular injury

📐 The adult catheter is 90 cms long

#anaesthesia , #anesthesia

Tuesday, September 6, 2016

HOW METABOLISM AFFECTS THE JOURNEY OF DRUGS TO THE TARGET SITE❓

🚀Oral administration --> cross the gut mucosa --> enter portal circulation -->  pass through the liver -->  enter the systemic circulation. 

🚀Only un-ionised molecules can cross the mucosal barrier

🚀Weakly acidic drugs (e.g. aspirin) begin to be absorbed in the acidic environment of the stomach

🚀Weakly basic drugs only begin to be absorbed in the small intestine.

🚀Drugs that are permanently ionised (e.g. the NDMR) are not absorbed from the gut at all.

 🚀Metabolism occurring in the liver is called ‘first-pass’ metabolism. The metabolism which happens in gut wall as in case of NTG is also first-pass metabolism. First-pass metabolism reduces the amount of drug that reaches its target site.

🚀If liver is having a high metabolic capacity, in case of a particular drug, any drug entering the hepatocyte is quickly broken down. Now the drug fraction which is protein bound dissociates freely and enters hepatocyte. In this case the overall hepatic metabolism is mainly related to hepatic blood flow. E.g. Propranolol 

🚀In case of drugs with lower hepatic metabolic capacity remains bound to protein and so,  the degree of protein binding influences entry to the hepatocyte than the hepatic blood flow 

🚀Sublingual and nasal routes have the advantage of rapid onset and bypassing of the portal circulation and hence avoidance of first-pass metabolism.

🚀Rectal  route also avoids first-pass metabolism, but absorption is slow and can be incomplete.