Thursday, October 20, 2016


🦂Is a common chronic pain condition, characterised by 

🖌Pain ( Spontaneous, widespread , diffuse, worse in the morning, hypersensitivity to all painful stimuli, >3 months duration, 11 out of 18 defined tender points produce tenderness on digital palpation)

🖌 Sleep disturbances

🖌 Fatigue 

🦂Pathophysiology may include 

🖌dysfunction of descending inhibitory pathways 

🖌abnormal neurotransmitter release

🖌central sensitisation etc

🦂Tricyclic antidepressants ( like Amitriptyline 5-10 mg ) may be effective in fibromyalgia as they reduce pain & fatigue and improve sleep

🦂Other therapies used:

🖌 Pregabalin


🖌Newer MAO inhibitors like pirlindole



🖌Intravenous lignocaine

🖌Injection of trigger points

🖌Cognitive Behavioural Therapy

🖌Warm bath

🖌Complimentary therapies

#pain , #fibromyalgia , #PainManagement

Reference: Dedhia JT, Bone ME. Pain and fibromyalgia. Contin Educ Anaesth Crit Care Pain. 2009; 9(5): 162–166.

Tuesday, October 18, 2016



🐨 Pituitary tumours can be hypo or hyper secretory : so they may exhibit Cushingoid status or cortisol deficiency. Accordingly the anesthetist has to look for diseases which are associated with these conditions

🐨 During the Pre Anesthetic Check up (PAC), we should screen for the presence of factors affecting airway management, like

✔️ Macroglossia

✔️ Soft tissue hypertrophy

✔️Obstructive Sleep Apnea (OSA)

And also for other associations like

✔️ DM

✔️ Systemic Hypertension 

✔️ Ischemic Heart Disease

✔️ Heart failure

✔️ Pulmonary Hypertension 

 🐨 If there is cortisol deficiency ( can be diagnosed by short synacthen test) glucocorticoid supplementation should be continued peri-operatively.

🐨 The trans nasal trans sphenoidal approach offers better visibility and lesser incidence of postoperative Diabetes Insipidus (DI). NB: Both DI and SIADH can occur as postoperative complications; but incidence of DI is much higher (upto 50%) compared to that of SIADH.

🐨Trans nasal surgery requires oro-tracheal intubation, insertion of a throat pack to prevent blood going to trachea and stomach and infiltration of the nasal mucosa with local anesthetic and vasopressor ( by surgeon )

🐨 Establishment of an arterial line will help to intervene promptly during hemodynamic fluctuations that happens with infiltration or intense surgical stimulation 

🐨 Surgeon may request various 'helps' from the anesthesiologist to make the suprasellar part of the tumor prolapse down into the sella, like:

✔️ Insertion of a lumbar drain and letting out of CSF

✔️ Maintenance of hypercapnea (upto 60 mm of Hg)

✔️ Fluid administration

🐨 As the patient is positioned with upper part of trunk and head elevated, there is chance for venous air embolism

🐨 Use of short acting drugs facilitate a rapid and smooth emergence which will help in neurological assessment 

🐨 Presence of blood in pharynx, nasal packs and preexisting OSA, pose additional problems in managing the airway

🐨 We can't apply a nasal CPAP mask in such cases as it can cause pneumocephalus, meningitis and air embolism

Reference: Lim M, Williams D, Maartens N. Anaesthesia for pituitary surgery. J Clin Neurosci. 2006; 13(4): 413–418.

Thursday, October 13, 2016


✔️ Inherited as Autosomal Dominant (Ⓜ️NEMO> Sickle Cell Disease is a SAD disease; S=SCD, AD=Autosomal Dominant)

✔️ A single DNA base change ( Beta chain) causes SCD

✔️ DNA base change is Adenine for Thymine & the resultant amino acid change is Valine for Glutamic Acid ( Ⓜ️NEMO> Addition of bases other than Thymine results in Valueless Goods )

✔️ Thus Hb S is produced. As Valine is hydrophobic, the deoxygenated Hb is less water soluble and gets precipitated & polymerized inside the RBC

✔️ This polymerization slightly reduces the overall affinity for O2; otherwise the affinity for O2 is same for Hb A and Hb S

✔️ These changes also make the RBS more rigid and contributes to sickling and microvascular occlusion

✔️ Regarding hypoxaemia, HbS will precipitate at a PO2 of 5–6 kPa (37-45 mm of Hg). As venous PO2 lies in this range, in case of homozygous individuals having only abnormal Hb will have continuous sickling

✔️ Patients with sickle cell trait experience sickling at much lower partial pressures (2.5–4 kPa / 19-30 mm of Hg )

✔️ Sickledex test produces a turbidity and becomes positive even with a very small amount of Hb S: so it CAN NOT differentiate between homo & heterozygous states

Reference: Smith T, Pinnock C, Lin T. Fundamentals of Anaesthesia, 3rd edn. Cambridge: Cambridge University Press, 2009; pp. 234–5 

#Anesthesia , #hematology , #medicine , #SickleCellDisease

Tuesday, October 11, 2016


🔸The ICP waveform is a modified arterial pressure tracing

🔸 It has 3 peaks: P1, P2 & P3

🔸 P1 is a result of transmitted pressure from choroid plexus

🔸 The amplitude of P2 changes with brain compliance. If compliance is poor, amplitude will be high ( can even exceed that of P1) and vice versa

🔸P3 represents the dicrotic notch

🔸 Lundberg (A) or Plateau waves are steep rise of ICP to over 50 mm of Hg and lasting for 5-20 minutes; then it falls abruptly. Are always pathological and indicates significantly reduced compliance

🔸 Lundberg (B) waves are oscillations occurring every 1-2 minutes where ICP rises to over 20-30 mm of Hg from baseline in a crescendo manner. They are supposed to be result of altered cerebral (B)lood volume and altered tone of cerebral (B)lood vessels 

🔸 Lundberg (C) waves are oscillations whose amplitude is less than that of B waves and are supposed to result because of interactions between cardiac and respiratory (C)ycles. They occur also in healthy individuals 


 Intraventricular catheter - ventriculostomy represents the "gold standard" for pressure measurement
✔️Normally placed in the frontal horn of lateral ventricle 

✔️Allows therapeutic CSF drainage 

✔️Creates a pathway for infection 

✔️Potential for accidental venting of CSF

✔️Possible subdural haemorrhage or upward brain herniation 

✔️ Catheter obstruction & ventricular haemorrhage may occur 

 Subdural bolt 

✔️ "Richmond Screw" or "Leeds device" inserted through a burr hole & an opening in the dura & arachnoid remains intact
✔️connects via a fluid couple to a transducer 

✔️ less invasive 

✔️ may underestimate high ICP and damping is a problem

 Subdural catheter 

✔️ Usually subdural space over frontal lobe of non-dominant hemisphere is selected
✔️ Prone to signal damping and calibration drift 

✔️ Potential risk of infection 

✔️ Doesn't require penetration of brain tissue

 Intracerebral transducer 

✔️Inability to check zero calibration & drain CSF 

✔️ Risk of infection

✔️Less reliable

🔸The incidence of infection ~ 2-7% with monitoring ≥ 5 days

🔸The risks are slightly greater with dural penetration 

🔸The zero reference point of the transducer is usually taken as the external auditory meatus 

🔸 Rather than the waveform type, the important factors appear to be the degree and duration of ICP elevation


🚶🏻Tyrosine derived from thyroglobulin is combined with iodine to produce T3 & T4 (Thyroxin)

🚶🏻T3 is 5 times more active than T4, though T4 is produced in larger amounts 


✔️ Increase the size & number of thyroid gland cells
✔️ Increase iodide binding
✔️ Increase the release of thyroglobulin into the colloid of the gland
✔️Increase pinocytosis of colloid by the thyroid cells
✔️Increase hormone production 
✔️ Increase release of already produced hormone from the bound thyroglobulin and into the bloodstream 

🚶🏻In bloodstream the hormones are 99% protein bound. 

🚶🏻Thyroxin Binding Globulin (TBG) has the greatest affinity; but Albumin has the greatest capacity for binding the hormones. Thyroxine-binding prealbumin (TBPA) also bind them


✔️ For regulation of the hormonal levels, the negative feedback is mediated by the unbound free fraction 
✔️ Stress inhibits production 
✔️ Warmth decreases production 
✔️ Cold increases production 
✔️ Glucocorticoids, dopamine & somatostatin inhibit TSH secretion

Reference: Smith T, Pinnock C, Lin T. Fundamentals of Anaesthesia, 3rd edn. Cambridge: Cambridge University Press, 2009; p. 474 .

#Thyroid , #Thyroxin , #Medicine , #Physiology

Wednesday, September 28, 2016


🔵 SSI is an index which measures the surgical stress response in patients under anesthesia

🔵 It assess the balance between the intensity of surgical stimulation and the level of antinociception (e.g. Opioid analgesia , neuraxial or nerve blockade)

🔵 SSI uses two continuous cardiovascular variables, both obtained from Photo Plethysmography (PPG) waveforms of SpO2 

(1) The interval between successive hearts beats (HBI) 

(2) PPG amplitude (PPGA) 

🔵Photoplethysmography (PPG), i.e. pulse oximetry, is primarily used to produce an estimation of the relative concentration of oxyhemoglobin in blood.

🔵 PPG is related to volume changes and contains information about the peripheral blood circulation, including skin vasomotion. Skin vasomotion is controlled by the sympathetic nervous system, which is activated during surgical stress.

🔵 Changes in PPG amplitude (PPGA) reflect changes in the peripheral vascular bed, controlled by the sympathetic nervous system . Increased PPGA response has been associated with nociception during general anesthesia.

🔵SSI values near 100 correspond to a high stress level, and values near zero to a low stress level.

🔵 In trials, SSI correlated positively with the intensity of painful stimuli and negatively with the analgesic concentration

🔵 SSI has been shown to be capable of differentiating decreases in HR achieved with opioid from those accomplished with a beta blocker (Ahonen et al. 2007). 

🔵 An optimal range for SSI during anesthesia has not yet been recommended.

Reference: Measurements of adequacy of anesthesia and level of consciousness during surgery and intensive care, Johanna Wennervirta, Department of Anesthesiology and Intensive Care Medicine, Helsinki University Hospital

#anaesthesia , #anaesthesiology , #anaesthesiologist


🎯 Most effective for children <20 Kg (~ under 6 years of age) and for dermatomes below T10

🎯Common side effects are weakness of legs, urinary retention etc

🎯 The incidence of epidural hematoma has been reported as 1 in 80000 cases

🎯 Because of this, sometimes a caudal block may necessitate overnight admission 

🎯 Dose calculation can be done using Armitage ( 0.5 mL/kg for lumbosacral & 1 mL/kg for lumbar blockade, with 0.25% levobupivacaine ) or Scott formulas

🎯 Additives used in caudal block:

💉 Preservative free Ketamine: Extend duration of analgesia; not used in infants <6 months of age due to fear of neurotoxicity 

 💉 Clonidine : Extend duration of analgesia; not used in preterm infants and neonates due to higher incidence of bradycardia and apnoea. Provides postoperative sedation also.

🎯 Opioids when used as additives produce side effects like respiratory depression, pruritus & PONV

#EpiduralBlock , #Anaesthesia , #Anesthesia

References: De Beer DAH, Thomas ML. Caudal additives in children: solutions or problems? Br J Anaesth. 2003; 90: 487–498. Patel D. Epidural analgesia for children. Contin Educ Anaesth Crit Care Pain. 2006; 6(2): 63–66.


🌋Carcinoid tumours are neuroendocrine tumours originating from enterochromaffin cells [GIT(~90%), gonads and bronchus mainly]

🌋 Some patients develop Carcinoid Syndrome, where the tumour secretes neuropeptides into systemic circulation 

🌋 Usually they undergo firstpass metabolism in liver

🌋 If the patient is becoming symptomatic, due to the neuropeptide secretion, it's either due to their production in large amounts to overwhelm the metabolic capacity of the liver or that they are released without going through the portal circulation 

🌋 They secrete bio-active compounds like serotonin, histamine, catecholamines, bradykinin, kallikrein, substance-P, motilin etc

🌋 This can cause symptoms like bronchospasm, hypotension, hypertension, flushing etc

🌋 Pharmacologic treatment of intraoperative/ acute/ hemodynamic crises are with i.v. Octreotide, whereas for treatment of chronic symptoms, Somatostatin analogues like Lanreotide are used. Octreotide can also be used for prophylaxis. Should be continued postoperatively.

🌋 Vasoactive drugs like catecholamines and histamine releasing drugs like morphine, atracurium, succinylcholine, thiopentone etc should be avoided. Use of a test dose may reduce adverse events. 

🌋 Antihistamines are also given prophylactically in case of gastric tumours

🌋 Another concern for the anesthesiologist in such patients is the possibility of Carcinoid heart disease.  Here, the patient develops thickened valves resulting in tricuspid and pulmonary regurgitation and pulmonary stenosis (mitral and aortic insufficiency can also occur,; but are less frequent). Pericarditis or myocardial metastases can also occur.

#Anesthesia , #Anaesthesia , #anesthesiologist