The portal vein arises from the splenic and mesenteric veins, and is the biggest vessel in the portal venous system, accounting for about 75% of the hepatic blood flow.

It is responsible for draining blood from parts of the gastrointestinal system, the spleen, the pancreas and the gallbladder into the liver.

Pituitary macroadenoma is a benign tumour with growth larger than 10mm (those under 10mm are called microadenoma)

Compression of optic chiasm by pituitary adenoma is responsible for causing visual field defects like bitemporal hemianopia, optic neuropathy.

Bell’s palsy is facial muscle weakness or paralysis that arises from idiopathic damage to the facial nerve. It can occur at any age but is commonly associated with some conditions:
1. pregnancy
2. diabetes
3. upper respiratory ailment
4. GBS
5. Toxins

The common symptoms of Bell’s palsy are:
1. Abnormal corneal reflex as the facial nerve controls the motor aspect of the corneal reflex.
2. The loss of control of facial muscles and eyelids leads to decreased tear production.
3. mild weakness to total paralysis on one side of the face, occurring within hours to days.
4. Bell’s palsy is a lower motor neuron lesion that usually spares the forehead while the upper motor near lesions, like stroke, involves the entire face.
5. The anterior two-thirds of the tongue is supplied by the chorda tympani branch of the facial nerve, thus resulting in loss of taste.
6. Ptosis can be a feature of Bell’s palsy but Bell’s palsy would typically show unilateral symptoms rather than bilateral.

Penicillinase is a narrow spectrum ?-lactamase that opens the ?-lactam ring and inactivates Penicillin G and some closely related congeners. The majority of Staphylococci and some strains of gonococci, B. subtilis, E. coli, and a few other bacteria produce penicillinase.

N. meningitidis is sensitive to penicillin and less than 20% resistance is found in pseudomonas.

Desflurane is a highly fluorinated methyl ethyl ether used for the maintenance of general anaesthesia. It has been identified as a weak triggering anaesthetic of malignant hyperthermia. That, in the absence of succinylcholine, may produce a delayed onset of symptoms.

Level 1 – High-quality randomised controlled trial with statistically significant difference or no statistically significant difference but narrow confidence intervals (prospective controlled)

Level 2 – Prospective comparative study (prospective uncontrolled)

Level 3 – Case-control study, retrospective comparative study (retrospective controlled)

Level 4 – Case series (retrospective uncontrolled)

Level 5 – Expert opinion.

The following are some basic assumptions:

Extracellular fluid (ECF) makes up one-third of total body water (TBW), while intracellular fluid makes up the other two-thirds (ICF).
One-quarter of ECF is plasma, and three-quarters is interstitial fluid (ISF).
The volume receptors have a 7-10% blood volume change threshold. The osmoreceptors are sensitive to changes in osmolality of 1-2 percent.
Prior to the transfusion, the plasma osmolality is normal (between 287 and 290 mOsm/kg).
[Na+] in 0.9 percent N. saline is 154 mmol/L, which is similar to that of extracellular fluid. When given intravenously, this limits its distribution within the extracellular space, resulting in a plasma compartment:ISF volume ratio of 1:3.
In this time frame, one litre of 0.9 percent N. saline will increase plasma volume by about 250 mL, which could be the threshold for activation of the volume receptors in the atria, resulting in the release of atrial natriuretic peptide (ANP).

Because 0.9 percent N. saline is isosmotic, after a 1 L infusion, plasma osmolality will not change. No changes in antidiuretic hormone secretion will be detected by the hypothalamic osmoreceptors.

Because normal saline is protein-free, the oncotic pressure in the blood is slightly reduced after the saline infusion. As a result, fluid movement into the ISF is favoured (Starling’s hypothesis), and the lower oncotic pressure causes an immediate increase in the glomerular filtration rate (GFR) and a reduction in water reabsorption in the proximal tubule.

The flow of urine increases. There is no hormonal intermediary in this effect, so it is strictly local. Urine flow immediately increases. The fluid returns to the intravascular compartment, and urine flow continues until all of the transfused fluid has been excreted.

Blood pressure changes associated with a 1 L fluid infusion are unlikely to affect high-pressure baroreceptors in the carotid sinus.

The juxta-glomerular cells of the afferent arteriole are adjacent to the specialised cells (macula densa) of distal tubules. The sodium and chloride ions in the tubular fluid are detected by the macula densa. Renin release is inhibited when the tubular fluid contains too much sodium chloride. Hormonal changes take longer to manifest than physical changes that control glomerulotubular balance.
Hypertonic saline, not 0.9 percent N saline, is an osmotic diuretic.

The concentration of solute particles per litre (mosm/L) = the osmolarity of a solution. Changes in water content, ambient temperature, and pressure affects osmolarity. The osmolarity of any solution can be calculated by adding the concentration of key solutes in it.

Individual manufacturers of crystalloids and colloids may have different absolute values but they are similar to these.

0.45% N. Saline with 5% glucose:
Tonicity – hypertonic
Osmolarity – 405 mosm/L
Kilocalories (kCal) – 107

0.9% N. Saline:
Tonicity – isotonic
Osmolarity – 308 mosm/L
Kilocalories (kCal) – 0

5% Dextrose:
Tonicity – isotonic
Osmolarity – 253 mosm/L
Kilocalories (kCal) – 170

Gelofusine (154 mmol/L Na, 120 mmol/L Cl):
Tonicity – isotonic
Osmolarity – 274 mosm/L
Kilocalories (kCal) – 0

Hartmann’s solution:
Tonicity – isotonic
Osmolarity – 273 mosm/L
Kilocalories (kCal) – 9

Carbon dioxide absorbs the most infrared (IR) light between the wavelengths of 4.2-4.4m (4.26m is ideal).

Nitrous oxide absorbs infrared light at wavelengths of 4.4-4.6m (very similar to CO2) and less so at 3.9m.

At a frequency of 4.7m, carbon monoxide absorbs the most IR light.

At 3.3 m and throughout the ranges 8-12 m, the volatile agents have strong absorption bands.

Although oxygen does not absorb infrared light, it collides with CO2 molecules, interfering with absorption. The absorption band is widened as a result of this (so called collision or pressure broadening). A drop of 0.5 percent in measured CO2 can be caused by 95% oxygen.

Nitrous oxide causes a greater inaccuracy of 0.1 percent per ten percent of nitrous oxide.

Water vapour absorbs infrared light as well, resulting in absorption band overlap, collision broadening, and partial pressure dilution. Water traps and water permeable tubing are used to reduce inaccuracies.

Collision broadening is compensated for in modern gas multi-gas analysers.

Only on rare occasions has it been found that the prevalence and incidence were same. Incidence can be greater than prevalence in acute cases only. In case of chronic diseases prevalence is far greater than incidence. One needs to have a deeper understanding of both the concepts to understand the health literature.

The pH of CSF is 7.31 which is lower than plasma.

Compared to plasma, it has a lower concentration of potassium, calcium, and protein and a higher concentration of sodium, chloride, bicarbonate and magnesium.

CSF usually has no cells present but if white cells are present, there should be no more than 4/ml.

The pressure of CSF should be less than 20 cm of water.

The concentration of glucose is approximately two-thirds of that of plasma, and it has a concentration of approximately 3.3-4 mmol/L.

Certain skeletal muscles are more resistant to the effects of neuromuscular blocking agents, both non-depolarizing and depolarizing. The diaphragm is the most resistant. The muscles of the larynx and the corrugator supercilii are less resistant. The abdominal, orbicularis oris, and limb peripheral muscles are the most sensitive muscles.

Twitch stimulation patterns:

Supramaximal single stimulus:

The frequency ranges from 1 Hz to 0.1 Hz (one every second to one every 10 seconds)
The response is proportional to the frequency of the event.
It has limited clinical utility because it only tells you whether or not a patient is paralysed (no information on degree of paralysis).

Over the course of 0.5 seconds (2 Hz), four supramaximal stimulate were applied:

It is possible to see ‘fade’ and use it as a basis for evaluation.
This stimulation pattern is used to determine the degree of blockade (1-2 twitches is appropriate for abdominal surgery)
If the train of four (TOF) count is 1-2, reversal agents can be used in conjunction with medium-acting neuromuscular blocking agents.

Ratio of TOF:

This is the ratio of the 4th twitch amplitude to the 1st twitch amplitude.
The ratio decreases with non-depolarising block and is inversely proportional to the degree of block, allowing objective measurement of residual neuromuscular blockade.
To achieve adequate reversal, the ratio (as measured by accelerography) must be between 0.7 and 0.9.

Count of twitches after a tetanic experience(PTC):

50 Hz for 5 seconds, then a 3 second pause, followed by a single 1 Hz twitch stimulus.
When the TOF count is zero, this stimulation pattern is used to assess deep blockade (that is, in neurosurgery, microsurgery or ophthalmic surgery when even small movements of a patient will disturb the surgical field)
It gives an estimate of how long it will take for the response to return to single twitches, allowing assessment of blocks that are too deep for any other technique.
A palpable post-tetanic count (PTC) of 2 indicates no twitch response for about 20-30 minutes, and a PTC of 5 indicates no twitch response for about 10-15 minutes.

This is without a doubt the best way to keep track of paralysis in patients who need to avoid diaphragmatic movement. It’s best to use drug infusions and aim for a PTC of 2. After a tetanic stimulus, acetylcholine is mobilised, causing post-tetanic potentiation.

Stimulation in Two Bursts:

750 milliseconds between two short bursts of 50 Hz
This stimulation pattern is used to assess small amounts of residual blockade manually (tactile).

Choosing an appropriate dose of local anaesthetic to reduce the chance of toxicity is the most important safety aspect in performing a caudal block.

The caudal will have to be inserted following induction of anaesthesia as performing it in an awake child is not a viable option.

The patient is placed in the lateral position and the sacral hiatus is identified. Under strict asepsis, a needle ( usually a 21-23FG needle) is advanced at an angle of approximately 55-65° to the coronal plane at the apex of the sacrococcygeal membrane. When there is loss of resistance, thats the endpoint. The needle must first be aspirated before anaesthetic agent is injected because there is a risk (1 in 2000) of perforating the dura or vascular puncture.

Alternatively, a 22-gauge plastic cannula can be used. Following perforation of the sacrococcygeal membrane, the stilette is removed and only the blunter plastic cannula is advanced. This reduces the risk of intravascular perforation.

Eliciting an appropriate end motor response at an appropriate current strength when the caudal and epidural spaces are stimulated helps in improving the efficacy and safety of neural blockade. A 22G insulated needle is advanced in the caudal canal until a pop is felt. If the needle is placed correctly, an anal sphincter contractions (S2 to S4) is seen when an electrical stimulation of 1-10 mA is applied.

The application of ultrasound guidance in identification of the caudal epidural space has been shown to prevent inadvertent dural puncture and to increase the safety and efficacy of the block in children.

Spirometry measures the total volume of air that can be forced out in one maximum breath, that is the total lung capacity (TLC), to maximal expiration, that is the residual volume (RV).

It is conducted using a spirometer which is capable of measuring lung volumes using techniques of dilution.

During spirometry, the following measurements can be determined:
Forced vital capacity (FVC)/vital capacity (VC): The maximum volume of air exhaled in one single forced breathe.
Forced expiratory volume in one second (FEV1)
FEV1/FVC ratio
Peak expiratory flow (PEF): the maximum amount of air flow exhaled in one blow.
Forced expiratory flow (mid expiratory flow): the flow at 25%, 50% and 75% of FVC
Inspiratory vital capacity (IVC): The maximum volume of air inhaled after a full total expiration.

Anatomical dead space is measured using a single breath nitrogen washout called the Fowler’s method.

Residual volume and total lung capacity are both measured using the body plethysmograph or helium dilution

The functional residual capacity is usually measured using a nitrogen washout or the helium dilution technique.

Chest compressions are an essential part of cardiopulmonary resuscitation (CPR) which helps restore spontaneous circulation (ROSC).

Sodium bicarbonate is only prescribed in patients with cardiac arrests as a result of an overdose of tricyclic antidepressants or hyperkalaemia. Its use causes the body to produce more CO2 which causes:

Exacerbation of intracellular acidosis
Negative inotropy to ischaemic myocardium
Increased osmotic load of sodium into failing brain and body
Shift of oxygen dissociation curve to the left.

THAM is often used to treat metabolic acidosis as a result of cardiac bypass surgery and also cardiac arrest, when other standard methods have failed.

Carbicarb (Na2CO3 0.33 molar NaHCO3 0.33 molar) has only mild effects on acidosis. It also causes an increase in arterial CO2 pressure and lactate concentration.

Prostaglandins do not play a major role in regulating RBF in healthy resting individuals. However, during pathophysiological conditions such as haemorrhage and reduced extracellular fluid volume (ECVF), prostaglandins (PGI2, PGE1, and PGE2) are produced locally within the kidneys and serve to increase RBF without changing GFR. Prostaglandins increase RBF by dampening the vasoconstrictor effects of both sympathetic activation and angiotensin II. These effects are important because they prevent severe and potentially harmful vasoconstriction and renal ischemia. Synthesis of prostaglandins is stimulated by ECVF depletion and stress (e.g. surgery, anaesthesia), angiotensin II, and sympathetic nerves.

Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, potently inhibit prostaglandin synthesis. Thus administration of these drugs during renal ischemia and hemorrhagic shock is contraindicated because, by blocking the production of prostaglandins, they decrease RBF and increase renal ischemia. Prostaglandins also play an increasingly important role in maintaining RBF and GFR as individuals age. Accordingly, NSAIDs can significantly reduce RBF and GFR in the elderly.

Being the part of a meta analysis, forest plots are more valued as evidence then randomised control trials.

The notion that forest plots can only be used if the results are substantial is not true. They are good indicators of the significance of the data. If the diamond intersects the central line, the data is rendered significant. It also aggregates means and confidence intervals from studies conducted in the past which makes the study much more reliable as errors associated with individual studies tend to have less of an impact in this way.

The suggestion that forest plots are primarily used for qualitative data is factually incorrect. Forest plots require numerical values to function.

All in all, forest plots help us in determining whether or not there is a significant trend in that particular field of study.

Observation bias occurs when the behaviour of an individual changes that results from their awareness of being observed.

Recall bias introduced when participants in a study are systematically more or less likely to recall and relate information on exposure depending on their outcome status.

Attrition bias is a systematic error caused by unequal loss of participants from a randomized controlled trial (RCT). In clinical trials, participants might dropout due to unsatisfactory treatment or efficacy, intolerable adverse events, or even death.

Selection bias introduced when the individuals are not chosen randomly to take a part in the study. It usually occurs when the research decides who is going to be studied, they are not the representative of the population.

Lead-time bias occurs when a disease is detected by a screening test at an earlier time point rather than it would have been diagnosed by its clinical appearance. In this bias, earlier detection improves the survival time in the intervention group.

Patients who present for surgery may be on prescription medication or natural/herbal therapies. These have relevance for anaesthesia since they can cause drug interactions.

Ephedra (Ma Huang) is a drug derived from the plant Ephedra sinica that is used as a CNS stimulant, weight reduction aid, and asthma therapy. It is a combination of alkaloids that includes ephedrine which stimulates noradrenaline release from pre-synaptic neurones by acting directly on alpha and beta adrenoreceptors. The use of sympathomimetic drugs together can cause cardiovascular instability.

Ginkgo Biloba contains anti-oxidant characteristics and is used to treat Alzheimer’s disease, vascular dementia, and peripheral vascular disease. It lowers platelet adhesiveness and raises the risk of bleeding by decreasing platelet activating factor (PAF), especially in individuals who are also taking anticoagulants and antiplatelet drugs.

The extract from St. John’s Wort is utilised as an antidepressant because it is a cytochrome P450 isoenzyme inhibitor as well as a serotonin uptake inhibitor. When drugs like fentanyl or tramadol are used during an anaesthetic, there is a risk of serotonin syndrome developing.

The root of a pepper is used to make kava (Piper methysticum). It is a weak GABAA agonist which has the potential to augment the effects of propofol and benzodiazepines, which are volatile anaesthetics.

Garlic is made from the allium sativum plant and is used to treat hypertension and hyperlipidaemia. It includes cysteine, which inhibits platelet aggregation irreversibly, amplifying the effects of aspirin and NSAIDs.

Echinacea is a common herbal medicine that stimulates the immune system by modulating cytokine signalling. In individuals who require organ transplantation, it should be avoided.

Eye damage is the most common potential hazard associated with laser energy. Everyone in the laser treatment room has the risk of eye exposure when working with a Class 3b or Class 4 healthcare laser system, and damage to various structures in the eye depending on wavelength of the laser if they are unprotected.

Red and near-infrared light (400-1400 nm) has very high penetration power. The light causes painless burns on the retina after it is absorbed by melanin in the pigment epithelium just behind the photoreceptors.

Infrared radiation (IR), or infrared light (>1060 nm), is a type of radiant energy that’s invisible to human eyes and hence won’t elicit the protective blink.

Ultraviolet light (<400 nm) is also a form of electromagnetic radiation which is can penetrate the cornea and be absorbed by the iris or the pupil and cause burn injuries or cataract occur due to irreversible photochemical retinal damage. Safety eyewear is the best method of providing eye protection and are designed to absorb light specific to the laser being used. Laser protective eyewear (LPE) includes glasses or goggles of proper optical density (OD). The lenses should not be glass or plastic. The LPE should withstand direct and diffuse scattered laser beams. The laser protection supervisor (LPS) or LSO is an individual who is responsible for any clinical area in which lasers are used. They are expected to have a certain level of equipment and determine what control measures are appropriate, for each individual system, but their presence does not guarantee the chances of having an eye injury. Class 1 lasers are generally safe under every conceivable condition and is not likely to cause any eye damage. Class 3b or Class 4 medical laser systems are utilized in healthcare which have their own safety precautions. Polarized spectacles can make your eyes more comfortable by eliminated glare, however, they will not be able to offer any protection against wavelengths at which laser act.
Using short bursts to reduce energy is also not correct as it would still be harmful to eye.

The structures in the porta hepatis from anterior to posterior are:

The ducts: Most anterior are the left and right hepatic ducts.

The arteries: Next are the left and right hepatic arteries

The veins: Next is the portal vein

The epiploic foramen of Winslow lies most posterior at the porta hepatis.

The heart receives blood supply from coronary arteries. The right and left coronary arteries branch off the aorta and supply oxygenated blood to all heart muscle parts.

The left main coronary artery branches into:
1. Circumflex artery – supplies the left atrium, side, and back of the left ventricle. The left marginal artery arises from the left circumflex artery. It travels along the obtuse margin of the heart.
2. Left Anterior Descending (LAD) artery – supplies the front and bottom of the left ventricle and front of the interventricular septum

The left anterior descending coronary artery is the largest coronary artery. It courses anterior to the interventricular septum in the anterior interventricular groove, extending from the base of the heart to its apex. Around the apex, the LAD anastomosis with the terminal branches of the posterior descending artery (branch of the right coronary artery).
Atherosclerosis or thrombotic occlusion of LAD causes myocardial infarction in large areas of the anterior, septal, and apical portions of the heart muscle. It can lead to a serious deterioration in heart performance.

Occlusion of the LAD causes anteroseptal myocardial infarction, which is evident on the ECG with changes in leads V1-V4. Occlusion of the left circumflex artery causes lateral, posterior, or anterolateral MI. However, as it does not run towards the apex in the interventricular septum of the heart, it is not the correct answer for this question.

The right coronary artery branches into:
1. Right marginal artery
2. Posterior descending artery

The right coronary artery supplies the right atrium, right ventricle, interatrial septum, and the inferior posterior third of the interventricular septum. Occlusion of the right coronary artery causes inferior MI, which is indicated on ECG with changes in leads II, III, and aVF.

Drug A is a pure agonist for the receptor, with high intrinsic efficacy and affinity, according to the log-dose response curve.

Drug B, on the other hand, works as a competitive antagonist. It binds to the receptor but has no inherent efficacy. Drug A’s efficacy will not change, but its potency will be reduced.

A partial agonist is a drug with partial intrinsic efficacy and affinity for the receptor. Giving a partial agonist after a pure agonist will not increase receptor occupancy or decrease receptor activity, and thus will not affect drug A’s efficacy. The inverse agonist flumazenil can reverse all benzodiazepines.

An inverse agonist is a drug that binds to the receptor but has the opposite pharmacological effect.

A non-competitive antagonist is a drug that has affinity for a receptor but has different pharmacological effects and reduces the efficacy of an agonist for that receptor.

With respect to oxygen transport in cells, almost all oxygen is transported within erythrocytes. There is limited solubility and only 1% is carried as solution. Thus, the amount of oxygen transported depends upon haemoglobin concentration and its degree of saturation.

Haemoglobin is a globular protein composed of 4 subunits. Haem is made up of a protoporphyrin ring surrounding an iron atom in its ferrous state. The iron can form two additional bonds – one is with oxygen and the other with a polypeptide chain.
There are two alpha and two beta subunits to this polypeptide chain in an adult and together these form globin. Globin cannot bind oxygen but can bind to CO2 and hydrogen ions.
The beta chains are able to bind to 2,3 diphosphoglycerate. The oxygenation of haemoglobin is a reversible reaction. The molecular shape of haemoglobin is such that binding of one oxygen molecule facilitates the binding of subsequent molecules.

The oxygen dissociation curve (ODC) describes the relationship between the percentage of saturated haemoglobin and partial pressure of oxygen in the blood.
Of note, it is not affected by haemoglobin concentration.

Chronic anaemia causes 2, 3 DPG levels to increase, hence shifting the curve to the right

Haldane effect – Causes the ODC to shift to the left. For a given oxygen tension there is increased saturation of Hb with oxygen i.e. Decreased oxygen delivery to tissues.
This can be caused by:
-HbF, methaemoglobin, carboxyhaemoglobin
-low [H+] (alkali)
-low pCO2
-ow 2,3-DPG
-ow temperature

Bohr effect – causes the ODC to shifts to the right = for given oxygen tension there is reduced saturation of Hb with oxygen i.e. Enhanced oxygen delivery to tissues. This can be caused by:
– raised [H+] (acidic)
– raised pCO2
-raised 2,3-DPG
-raised temperature

Propofol is a short-acting medication used for starting and maintenance of general anaesthesia, sedation for mechanically ventilated adults, and procedural sedation.
The dose of propofol is 1-2 mg/kg.

Dose of some other important drugs are listed below:
Thiopental dose: 3-7 mg/kg
Ketamine dose: 1-2 mg/kg
Etomidate dose: 0.3 mg/kg
Methohexitone dose: 1.0-1.5 mg/kg

Hepatotoxicity due to halothane administration is relatively common and is a major factor in its rapidly declining use. Type 1 hepatotoxicity has an incidence of 20% to 30%. A comprehensive report in 1969 demonstrated an incidence of type 2 hepatotoxicity (hepatitis) of 1 case per 6000 to 20000 cases, with fatal cases occurring approximately once in 35000 patients following a single exposure to the anaesthetic. This incidence of fatal cases increases to approximately 1 in 1000 patients following multiple exposures. Following this study was a large-scale review in the United Kingdom, which showed similar results. To put this into perspective, there is only a single case of hepatotoxicity confirmed after the administration of desflurane and 2 cases per 1 million after enflurane. By the 1970s, halothane was the most common cause of drug-induced liver failure.

Halothane-induced hepatotoxicity has a female to male ratio of two to one. Younger patients are less likely to be affected; 80% of the cases are typically in patients 40 years or older. Other risk factors include obesity and underlying liver dysfunction. Medications such as phenobarbital, alcohol, and isoniazid may play a role in affecting CYP2E1 metabolism, increasing one’s risk.

The subclavian artery and vein have a similar path throughout their course, with the subclavian vein running anterior to the subclavian artery. The artery and vein are separated by the insertion of the scalenus anterior muscle.

There are three scalene muscles, found on each side of the neck:
1. Anterior scalene
2. Middle scalene
3. Posterior scalene

The scalenus anterior muscle is the anterior most of the three scalene muscles. It originates from the transverse processes of vertebrae C3-C6 and is inserted in the first rib.

The blood alcohol concentration depends on:

-The rate of alcohol absorption from the gastrointestinal tract
-The volume of distribution of alcohol in the body, and
-The rate of elimination of alcohol from the body.

Total body water is approximately 50% in a female as compared to 60% in a typical male. This means that the volume of distribution of alcohol is lower in female compared with men. This is the principal reason for higher peak in alcohol levels.

About 4% of ingested alcohol is metabolised by the liver accounting for first pass metabolism and 0.4% is metabolised by gastric alcohol dehydrogenase (ADH). The absorbed alcohol is NOT distributed to fat cells but it is distributed throughout the water compartments (plasma, interstitial and intracellular) of the body. Women have very little gastric ADH, which further influences this exaggerated rise.

85-98% of the alcohol is oxidised by the liver to acetaldehyde and then to acetate. The metabolic pathway initially observes first order kinetics and then saturation or zero order kinetics leading to peaks in alcohol levels.

Clearance of ethanol per unit lean body mass is lower in male. The calculated alcohol elimination rate and liver volume per kilogram of lean body mass were 33% and 38% higher in women than in men, respectively.

Available evidence in the literature about the relationship of alcohol metabolism to the phases of the menstrual cycle is conflicting.

The intrinsic pathway is best assessed by the aPTT time.

D-dimer is a fibrin degradation product which is raised in the presence of blood clots.

A 50:50 mixing study is used to assess if a prolonged PT or aPTT is due to factor deficiency or a factor inhibitor.

The thrombin time is a test used to assess fibrin formation from fibrinogen in plasma. Factors that prolong the thrombin time include heparin, fibrin degradation products, and fibrinogen deficiency.

Intrinsic pathway – Best assessed by APTT. Factors 8,9,11,12 are involved. Prolonged aPTT can be seen in haemophilia and use of heparin.

Extrinsic pathway – Best assessed by Increased PT. Factor 7 involved.

Common pathway – Best assessed by APTT & PT. Factors 2,5,10 involved.

Vitamin K dependent factors are factors 2,7,9,10

The patient in the case has a fluid volume requirement of 30 mL/kg/day. His basic electrolyte requirement per day is:

Sodium at 2 mmol/kg/day x 110 = 220 mmol/day
Potassium at 1 mmol/kg/day x 110 = 110 mmol/day

His energy requirement per day is:

35 kcal/kg/day x 110 kg = 3850 kcal/day

One gram of glucose in fluid can provide approximately 4 kilocalories.

The following are the electrolyte components of the different intravenous fluids:

Fluid Na (mmol/L) K (mmol/L)
0.9% Normal saline (NSS) 154 0
0.45% NSS + 5% dextrose 77 0
0.18% NSS + 4% dextrose 30 0
Hartmann’s 131 5
5% dextrose 0 0

1000 mL of 5% dextrose has 50 g of glucose

Option B is inadequate for his sodium and caloric requirements (30 mmol of Na+ and 560 kcal). It is adequate for his K+ requirement (120 mmol of K+).

Option C is in excess of his Na+ requirement (462 mmol of Na+). Moreover, it does not provide any K+ replacement.

Option D is inadequate for his caloric requirement (600 kcal) and K+ requirement (60 mmol of K+). Moreover it does not provide any Na+ replacement.

Option E is in excess of his Na+ requirement (393 mmol of Na+), and is inadequate for his potassium requirement (15 mmol of K+)

Option A has adequate amounts for his Na+ (231 mmol of Na+) and K+ (120 mmol of K+) requirements. It is inadequate for his caloric requirement (600 kcal).