CAUSES OF DETERIORATION OF #GCS IN #NEUROSURGICAL #ICU

☑️IN A PATIENT WITH ANEURYSMAL-SAH, AFTER CLIPPING OR COILING 

❓Re-bleed 

❓Acute hydrocephalus 

❓Cerebral vasospasm 

❓Seizure

☑️ IN A PATIENT WITH TRAUMATIC BRAIN INJURY (#TBI)

❓Re-accumulation of haematoma 

❓ Haemorrhage into contusion 

❓ Oedema 

❓ Seizure

☑️IN A PATIENT, WHO UNDERWENT #CRANIOTOMY

❓ Haematoma (sub-dural/intracerebral etc.) 

❓ Oedema 

❓ Seizure 

❓ Pneumocephalus/ Air Encephalocoele

#NeuroAnesthesia , #NeuroCriticalCare , #NeuroIntensiveCare , #NeuroICU , #Anaesthesiology , #Anesthesiologist , #Anesthesia , #CriticalCare

#Brainstem Testing for diagnosis of #BrainDeath

➖The brain stem often fails from the rostral to caudal direction and therefore it is logical to undertake testing in the same manner.

▶️PUPILLARY REFLEXES : 

➖The pupillary light reflex involves cranial nerves II and III and localizes to midbrain. The pupils should be nonreactive to both direct and consensual light reflex. 

POINTS: 

➖Pinpoint pupils are indicative of damage to descending sympathetic fibers as a result of damage to pons. 

➖The size of the pupils only provides an indication of the site of brainstem involvement and is not crucial for testing brain stem death.

▶️OCULOCEPHALIC REFLEX :

➖It involves cranial nerves III, VI, and VIII and interneurons within the midbrain and pons. On head movement toward right or left, the eyes remain “fixed” on a point in an intact patient. In the brain-dead patient, the eyes move with the head, hence the name “dolls eye” reflex.

POINTS: 

➖Before performing this test the physician must rule out cervical fracture or instability. 

▶️CORNEAL REFLEX : 

➖The reflex tests the V, VII, and III cranial nerves and localizes entirely to the pons. In the intact patient, touching the cornea with a cotton swab causes eyelid closure. 

➖The eye rotates upward, demonstrating the cranial nerve III component, known as “bell’s phenomenon.”

▶️OCULOVESTIBULAR REFLEX :

 ➖The oculovestibular reflex tests cranial nerves III, VI, VIII, and IV. It involves the entire pons and midbrain. 

PROCEDURE : 

➖Elevate the head 30°C. Irrigate tympanic membrane with 50-cc iced water or saline. Wait 1 min for response. Repeat test on the other side after waiting 5 min. If the oculovestibular reflex is intact using cold water as stimulus, the eyes tonically deviate toward the side of the stimulus immediately followed by a fast recoil toward the contralateral side (apparent nystagmus). In the brain stem dead patient this response is absent.

▶️GAG AND COUGH REFLEXES :

 ➖They require a functioning medulla and test cranial nerves IX and X. Both reflexes should be absent in brain stem death. 

➖The cough reflex is easily tested by stimulation of carina by suction through the endotracheal tube. The gag reflex can be elicited by stimulating the posterior pharynx with a tongue blade. 

▶️APNEA TESTING : 

➖This final test aims to demonstrate the failure of medullary centers to drive ventilation. Apnea test should be the last brain stem reflex to be tested. 

OBJECTIVE:  

➖is to stimulate the medulla while avoiding hypoxia and hemodynamic compromise associated with acidosis secondary to hypercarbia. 

PROCEDURE: 

➖After ensuring preoxygenation for 10 min a blood gas is performed to confirm baseline PaCO2 and SaO2 . 

➖With oxygen saturation greater than 95% the ventilatior is disconnected inducing apnea for a period of time to achieve ETCO2 above 6 KPa (=45 mmHg). A repeat arterial blood gases is used to confirm that the PaCO2 is at least 6 KPa and the pH is less than 7.40. 

➖An oxygen flow rate of 2–5 L/min via an endotracheal catheter or in difficult cases CPAP may be used to maintain oxygenation till this state is attained. 

➖Apnea is continued for a further 5 min after a PaCO2 of 6 KPa (=45 mmHg) has been achieved. 

➖If there is no spontaneous respiratory response, a presumption of absence of respiratory activity is made. 

➖A further blood gas can be done to confirm that the PaCO2 has risen by 0.5 KPa (=4 mmHg) from the initial 45 mmHg baseline.

Reference: Brain Death in Neurosurgical Critical Care Amit Prakash,  Basil Matta , Essentials of Neurosurgical Anesthesia & Critical Care 2012

UPPER GI BLEED IN ICU PATIENTS: THE POINTS WHICH YOU SHOULD KEEP IN MIND

💥Incidence of overt Upper GI Bleed (UGIB) ranges from 1.5 to 8.5% of all ICU patients but may be as high as 15% if no prophylaxis is used.

💥RISK FACTORS 

☢Mechanical ventilation >48 h 

☢Coagulopathy – INR >1.5 or platelet count <50,000 

☢Others: ✔️ Shock ✔️Sepsis ✔️Hepatic failure ✔️Acute Renal failure ✔️Multiple trauma ✔️Burns >35% of total body surface area ✔️Organ transplantation ✔️Head trauma ✔️Spinal trauma ✔️History of PUD or UGIB

💥SPECIFIC POINTS REGARDING TREATMENT 

🔸Thrombocytopenia can develop in neurosurgical patients on H2 Blockers

🔸The use of H2Bs and PPIs may increase the frequency of nosocomial pneumonia.

💥PROPHYLAXIS IS RECOMMENDED FOR ICU PATIENTS WHO EXHIBIT:

🔸Coagulopathy (platelet count < 50,000 per m 3 , INR > 1.5, partial thromboplastin time (PTT) >2 times the control value) 

🔸Mechanical ventilation >48 h 

🔸History of GI ulceration or bleeding within the past year 

🔸Two or more of the following risk factors: sepsis; ICU stay >1 week; occult GIB ≥6 days; glucocorticoid therapy (>250 mg hydrocortisone).

💥REASONS FOR UGIB IN ICU PATIENTS: 

🔸The glycoprotein mucous layer may be denuded by increased concentrations of refluxed bile salts or uremic toxins common in critically ill. Alternatively, or in addition, mucosal integrity may be compromised due to poor perfusion associated with shock, sepsis, and trauma. 

🔸Excessive gastrin stimulation of parietal cells has been detected in patients with head trauma as oppose to be normal or subnormal in most other ICU patients.

🔸Systemic steroids double the risk of a new episode of UGIB or perforation. Concomitant use with high doses of NSAIDs has been associated with a 12-fold increased risk for upper GI complications.

🔸Helicobacter pylori infection 

💥EMPIRICAL THERAPY

⚛ Start with an IV bolus of 80 mg and continue IV infusion at 8 mg/h for a total of 72 h. If no signs of rebleeding after 24 h, switch to oral PPI. 

⚛Octreotide is used in variceal bleeding. Start with an IV bolus of 50 mcg and continue IV infusion at 50 mcg/h for 3–5 days.

💥 UGIB IN HEAD INJURY & OTHER NEUROSURGICAL PATIENTS:

🔸They are more prone for UGIB because of ✔️ Frequent use of systemic steroids ✔️ Increased gastrin secretion ✔️ Significant gastric intramucosal acidosis is common in severe head injury. ✔️Primary insult to the central nervous system may result in derangement of splanchnic blood flow secondary to neurohumoral mechanisms.

🔸 In head injury, GI dysfunction also may manifest as ✔️gastroparesis✔️ileus, ✔️increased intestinal mucosal permeability, 

🔸 Plasma levels of cortisol and age are independent predictors of stress ulcers following acute head injury.

Reference: Gastrointestinal Hemorrhage in Neurosurgical Critical Care Meghan Bost, Kamila Vagnerova  , Ch:84, Essentials of Neurosurgical Anesthesia & Critical Care 2012 Strategies for Prevention, Early Detection, and Successful Management of Perioperative Complications

Static Compliance , Dynamic Compliance & Plateau Pressure

🔵 Compliance is a measurement of the distensibility of the lung

🔵 Compliance of both the chest wall and the lung tissue is known as Total Lung Compliance

🔵 Total Lung Compliance = Change in volume / Change in pressure 

🔵 Static Compliance is the truest measure of the compliance of the lung tissue

🔵 It is measured when there are no gases flowing into or out of the lungs

🔵 Static Compliance = Exhaled Tidal Volume /  (Plateau Pressure-PEEP)

🔵 The Plateau Pressure is obtained by instituiting a 2 second inspiratory pause at the peak of inspiration. This pause creates the condition of no gases flowing into the lungs.

🔵 This reflects the pressure due to the elastic recoil forces of the lung tissue alone . No pressure resulting from the flow of gases is measured. 

🔵 Normal value for Static Compliance is 70-100 mL/cm H2O. This means that for every 1 cm H2O pressure change in the lungs , there is a change in volume of 70-100 mL of gas

🔵 As Dynamic Compliance is a measurement taken while gases are moving in the lungs , it measures both the Compliance of the lung tissue and the resistance to air flow

🔵 It is easier to obtain as it doesn't require the inspiratory hold maneuver

🔵 Dynamic Compliance = Exhaled Tidal Volume / (Peak Inspiratory Pressure-PEEP)

🔵 The normal value for Dynamic Compliance is 50-80 mL/cm H2O

🔵 Dynamic Compliance measures are always always smaller than Static Compliance because Peak Airway Pressure is always greater than Plateau Pressure 

🔵 A decrease in Dynamic Compliance may indicate a decrease in lung compliance or an increase in airway resistance.

VITAMIN K

♈️Vitamin K is so named as it was originally called Koagulationsvitamin.

♈️The body stores about 1 week’s supply of vitamin K.

♈️Vitamin K is a fat-soluble vitamin

♈️ Vitamin K is required for the synthesis of six factors in the clotting cascade : factors II, VII, IX, X and the anticoagulants protein C and protein S.

♈️ γ -Carboxylation of these factors is carried out by the vitamin K-dependent carboxylase. This reaction subsequently allows calcium binding and the conformational change required to become active. The reaction involves the oxidation of vitamin K. Warfarin works by stopping the reversal of this oxidation.

♈️ Bile is required for absorption of vitamin K in the gut.

♈️ Menadiol, a synthesized form of vitamin K (K3), is water-soluble and therefore can be absorbed in conditions in which bile secretion is low. But, it is not recommended for use in neonates as it may produce haemolysis.

♈️ Haemorrhagic disease of the newborn is caused by a relative vitamin K deficiency.

♈️ Prophylaxis against haemorrhagic disease of the newborn is usually given at birth as an injection of the naturally occurring fat-soluble phytomenadione.

#VitaminK , #nutrition , #Vitamin , #medicine , #MedicalExam