To begin, one must determine the child’s approximate weight. There are a variety of formulas to choose from. It is acceptable to use the advanced paediatric life support formula:

(Age + 4) 2 = Weight

A 5-year-old child will weigh around 18 kilogrammes.

10 mcg/kg (0.1 ml/kg of 1 in 10 000 adrenaline) = 180 mcg is the appropriate dose of intravenous or intraosseous adrenaline.

The correct energy level to deliver is 4 J/kg, which equals 72 joules.

The pad size that is appropriate for this patient is 8-12 cm. For an infant, a 4.5 cm pad is appropriate.

To allow adequate separation in infants and small children, the pads should be placed anteriorly and posteriorly on the chest.

When using a bag and mask to ventilate, take two breaths for every 15 chest compressions. If chest compressions are being applied intubated and without interruption, a ventilation rate of 10-20 breaths per minute should be given.

Chest compressions should be done at a rate of 100-120 per minute, the same as an adult.

The ureter starts from the hilum of the kidney and has different relations with structures along its journey to the bladder.
It runs anterior to the psoas major muscle.
The testicular vessels (males) or the ovarian vessels (females) cross in front of the ureter.
The ureter passes in front of the common iliac artery where it bifurcates into the internal and external iliac arteries.
The ureter passes medial to the branches of the internal iliac vessel downwards and forwards to towards the bladder.
In males, the ductus deferens crosses the pelvic ureter medially.
In females. the ureter passes through the base of the broad ligament
In females, the pelvic part initially has the same relations as in males but, anterior to the internal iliac artery, it is immediately behind the ovary, forming the posterior boundary of the ovarian fossa. It is in extraperitoneal connective tissue in the inferomedial part of the broad ligament of the uterus. In the broad ligament, the uterine artery is anterosuperior to the ureter for approximately 2.5 cm and then crosses to its medial side to ascend alongside the uterus. The ureter turns forwards slightly above the lateral vaginal fornix and is, generally, 2 cm lateral to the supravaginal part of the uterine cervix in this location. It then inclines medially to reach the bladder.

Correlation doesn’t justify causality. Correlation coefficient gives us an idea whether or not the two parameters provide have any relation of some sort or not i.e. does change in one prompt any change in other? It has nothing to do with predictions. For that purpose linear regression is used.

Mapleson classified breathing systems into A, B, C, D and E. Jackson-Rees subsequently modified the Mapleson E by adding a double-ended bag to the end of the reservoir tubing, creating the Mapleson F. A Mapleson E or T-piece does not have a reservoir bag.

A Mapleson A system is a very efficient system for use during spontaneous ventilation. However, it is not suitable for use with patients less than 25 kg, due to the increased dead space at the distal / patient end. This system can be modified into a Lack system or coaxial Mapleson A, where the fresh gas flows through an outer tube (30 mm) and exhaled gases flow through the inner tube (14 mm).

The adjustable pressure limiting valve (APL) or expiratory valve allows exhaled gas and excess fresh gas to leave the breathing system. It is a one-way, adjustable spring-loaded valve, and gases escape when the pressure in the system exceeds the valve opening pressure. During spontaneous ventilation a pressure of less than 1 cm of water (0.1 kPa) is needed when the valve is in the open position (not 2 cm of H2O).

The reservoir bag is highly compliant and when over inflated, the rubber bag can limit the pressure in the system to about 40 cm of H2O.

This is due to the law of Laplace, which states that the pressure will fall as the radius of the bag increases:

Pressure = 2 x tension/radius.

Lorazepam is an intermediate-acting benzodiazepine that binds to the GABA-A receptor subunit to increase the frequency of chloride channel opening and cause membrane hyperpolarization.

Lorazepam has emerged as the preferred benzodiazepine for acute management of status epilepticus. Lorazepam differs from diazepam in two important respects. It is less lipid-soluble than diazepam, with a distribution half-life of two to three hours versus 15 minutes for diazepam. Therefore, it should have a longer duration of clinical effect. Lorazepam also binds the GABAergic receptor more tightly than diazepam, resulting in a longer duration of action. The anticonvulsant effects of lorazepam last six to 12 hours, and the typical dose ranges from 4 to 8 mg. This agent also has a broad spectrum of efficacy, terminating seizures in 75-80% of cases. Its adverse effects are identical to those of diazepam. Thus, lorazepam also is an effective choice for acute seizure management, with the added possibility of a longer duration of action than diazepam.

Phenobarbitone is a long-acting barbiturate that binds to GABA-A receptor site and increase the duration of chloride channel opening. It also blocks glutamic acid neurotransmission, and, at high doses, can block sodium channels. It is considered as the drug of choice for seizures in infants.

Phenytoin is an anti-seizure drug that blocks voltage-gated sodium channels. It is preferred in prolonged therapy of status epilepticus because it is less sedating.

In cases wherein airway protection is required, thiopentone and propofol are the preferred drugs.

The first rib is an atypical rib. It is short, wide, and flattened and lies in an oblique plane.

It has a small scalene tubercle on its medial border which marks the point of attachment of scalenus anterior. The lower surface lies on the pleura and is smooth.

The tubercle on the upper surface separates an anterior groove for the subclavian vein and a posterior groove for the subclavian artery and lower trunk of the brachial plexus.

Scalenus medius is attached to a roughened area posterior to the groove for the subclavian artery.

The upper surface gives attachment anteriorly to the subclavius muscle and costoclavicular ligament.

A compound that contains an asymmetric centre (chiral atom or chiral centre) and thus can occur in two non-superimposable mirror-image forms (enantiomers) are called chiral compounds.

Desflurane, Halothane, and isoflurane are chiral compounds but Sevoflurane is not a chiral compound.

The ascending cervical artery lies media the phrenic nerve on scalenus anterior and can easily be mistaken for the phrenic nerve at operation.

The phrenic nerve passes across scalenus anterior and medius inferiorly.

The subclavian artery is separated from the vein by the scalenus anterior.

The brachiocephalic vein is formed at the medial border of scalenus anterior by the subclavian vein and the internal jugular vein.

Emerging from the lateral border of scalenus anterior are the trunks of the brachial plexus .

With regards to the autonomic nervous system (ANS)

1. It is not under voluntary control
2. It uses reflex pathways and different to the somatic nervous system.
3. The hypothalamus is the central point of integration of the ANS. However, the gut can coordinate some secretions and information from the baroreceptors which are processed in the medulla.

With regards to the central nervous system (CNS)
1. There are myelinated preganglionic fibres which lead to the
ganglion where the nerve cell bodies of the non-myelinated post ganglionic nerves are organised.
2. From the ganglion, the post ganglionic nerves then lead on to the innervated organ.

Most organs are under control of both systems although one system normally predominates.

The nerves of the sympathetic nervous system (SNS) originate from the lateral horns of the spinal cord, pass into the anterior primary rami and then pass via the white rami communicates into the ganglia from T1-L2.

There are short pre-ganglionic and long post ganglionic fibres.
Pre-ganglionic synapses use acetylcholine (ACh) as a neurotransmitter on nicotinic receptors.
Post ganglionic synapses uses adrenoceptors with norepinephrine / epinephrine as the neurotransmitter.
However, in sweat glands, piloerector muscles and few blood vessels, ACh is still used as a neurotransmitter with nicotinic receptors.

The ganglia form the sympathetic trunk – this is a collection of nerves that begin at the base of the skull and travel 2-3 cm lateral to the vertebrae, extending to the coccyx.

There are cervical, thoracic, lumbar and sacral ganglia and visceral sympathetic innervation is by cardiac, coeliac and hypogastric plexi.

Juxta glomerular apparatus, piloerector muscles and adipose tissue are all organs under sole sympathetic control.

The PNS has a craniosacral outflow. It causes reduced arousal and cardiovascular stimulation and increases visceral activity.

The cranial outflow consists of
1. The oculomotor nerve (CN III) to the eye via the ciliary ganglion,
2. Facial nerve (CN VII) to the submandibular, sublingual and lacrimal glands via the pterygopalatine and submandibular ganglions
3. Glossopharyngeal (CN IX) to lungs, larynx and tracheobronchial tree via otic ganglion
4. The vagus nerve (CN X), the largest contributor and carries ¾ of fibres covering innervation of the heart, lungs, larynx, tracheobronchial tree parotid gland and proximal gut to the splenic flexure, liver and pancreas

The sacral outflow (S2 to S4) innervates the bladder, distal gut and genitalia.

The PNS has long preganglionic and short post ganglionic fibres.
Preganglionic synapses, like in the SNS, use ACh as the neuro transmitter with nicotinic receptors.
Post ganglionic synapses also use ACh as the neurotransmitter but have muscarinic receptors.

Different types of these muscarinic receptors are present in different organs:
There are:
M1 = pupillary constriction, gastric acid secretion stimulation
M2 = inhibition of cardiac stimulation
M3 = visceral vasodilation, coronary artery constriction, increased secretions in salivary, lacrimal glands and pancreas
M4 = brain and adrenal medulla
M5 = brain

The lacrimal glands are solely under parasympathetic control.

The left coronary artery arises from the left posterior aortic sinus and divides into the circumflex arteries and the left anterior descending (LAD) artery.

The right coronary artery arises from the anterior aortic sinus and supplies:
– the right ventricle
– part of the interventricular septum
– the atrioventricular (A-V) node and
– in 85% of cases the inferior part of the left ventricle.
The right coronary artery provides a posterior interventricular branch and a marginal branch that anastomoses with the LAD at the apex.

The oblique vein together with the small, middle and great cardiac veins drain into the coronary sinus, which drains into the right atrium.

The anterior cardiac vein drains directly into the right atrium.

Funnel plot is essentially a scatterplot of the effect of treatment against a particular measure of study precision. Its primal purpose is to serve as a visual aid and help in detection of bias or systematic heterogenity.

Because of the low pH in the stomach, paracetamol absorption is minimal (pKa value is 9.5). Paracetamol is absorbed quickly and completely in the alkaline environment of the small intestine. Oral bioavailability is approaching 100%. As a result, measuring paracetamol levels in plasma after an oral paracetamol dose has been used as a surrogate marker of gastric emptying. This method has been used to investigate the effects of drugs on gastric emptying. At clinically used doses, paracetamol is ideal because it has very few side effects.

Scintigraphic imaging is the gold standard for determining gastric emptying.

Although aspirin (acetyl salicylic acid) is absorbed primarily in the small intestine, some may also be absorbed in the stomach. The oral bioavailability ranges from 70 to 100 percent, making it less reliable than paracetamol.

Propranolol is a lipophilic drug that is rapidly absorbed after administration. However, it is highly metabolised by the liver in the first pass, and only about 25% of propranolol reaches the systemic circulation. It’s not the best indicator of gastric emptying.

Oral bioavailability of gentamicin and vancomycin is low. Only antibiotic-induced pseudomembranous colitis is treated with oral vancomycin.

Erythromycin is a pro-kinetic agent that acts as a motilin receptor agonist.

The option that is most responsible is the progressive decrease in venous return of blood to the right atrium. The heart rate does not usually change with PEEP so the fall in cardiac output is due to a reduction in left ventricular (LV) stroke volume (SV).

Note that the interventricular septum does shift toward the left and there is an increased pulmonary vascular resistance (PVR) from overdistention of alveolar air sacs that contribute to the reduction in cardiac output. Any increase in PVR will be associated with reduced pulmonary vascular capacitance.

The major action of ADH is to increase reabsorption of osmotically unencumbered water from the glomerular filtrate and decreases the volume of urine passed. The osmolarity of urine is increased to a maximum of four times that of plasma (approx. 1200 mOsm/kg) by Increasing water reabsorption.

Chronic water loading, Lithium, potassium deficiency, cortisol and calcium excess, all blunt the action of ADH. This leads to nephrogenic diabetes insipidus.

ADH’s primary site of action is the distal tubule and collecting duct.

Prilocaine is the drug of choice for intravenous regional anaesthesia. 0.5% prilocaine (40 ml) is indicated for this condition.
Lidocaine is another alternative for this condition but volume and dose are likely to be inadequate for the procedure.

There are different types of temperature measurement. These include:

Thermistor – this is a type of semiconductor, meaning they have greater resistance than conducting materials, but lower resistance than insulating materials. There are small beads of semiconductor material (e.g. metal oxide) which are incorporated into a Wheatstone bridge circuit. As the temperature increases, the resistance of the bead decreases exponentially

Thermocouple – Two different metals make up a thermocouple. Generally, in the form of two wires twisted, welded, or crimped together. Temperature is sensed by measuring the voltage. A potential difference is created that is proportional to the temperature at the junction (Seebeck effect)

Platinum resistance thermometers (PTR) – uses platinum for determining the temperature. The principle used is that the resistance of platinum changes with the change of temperature. The thermometer measures the temperature over the range of 200°C to1200°C. Resistance in metals show a linear increase with temperature

Tympanic thermometers – uses infrared radiation which is emitted by all living beings. It analyses the intensity and wavelength and then transduces the heat energy into a measurable electrical output

Gauge/dial thermometers – Uses coils of different metals with different co-efficient of expansion. These either tighten or relax with changes in temperature, moving a lever on a calibrated dial.

The tracheobronchial tree is subdivided into the conducting and the respiratory zones.

The zones from proximal to distal are:

Trachea
Bronchi
Bronchioles
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sacs

from the trachea to terminal bronchioles are the conducting zone while the respiratory zone is from the respiratory bronchioles to the alveola sacs

The metabolism of drugs in the liver occurs in 3 phases

Phase I: This involves functionalization reactions, which are of 3 types, namely hydrolysis, oxidation and reduction reactions catalysed by the cytochrome P450 (CYP) enzymes.

Phase II: This involves conjugation or acetylation reactions. The goal is to create water soluble metabolites that can be excreted from the body.

The liver is the second largest organ. It’s smallest functional unit is the acinus which is divided into 3 zones:

Zone I (periportal): This zone receives the largest amount of oxygen supply as it is the closest to the blood vessels. It is the site of plasma protein synthesis.

Zone II (mediolobular): This is located between the portal triad and central vein.

Zone III (centrilobular): This is closest to the central vein and receives the least amount of oxygen supply.

Kupffer cells are specialized macrophages found in the periportal zone of the liver, and function to remove foreign particles and breakdown red blood cells via phagocytosis.

Ito cells are fat-storing liver cells found in the space of Disse. Their function is to take-uo, store and secrete retinoids, as well as manufacture and release proteins that make up the extracellular matrix.

The left atrium is supplied by the left coronary artery and its major branch the left circumflex.

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.
The left marginal artery, a branch of the circumflex artery, supplies the left ventricle.
2. Left Anterior Descending (LAD) artery – supplies the front and bottom of the left ventricle and front of the interventricular septum

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. It also supplies the atrioventricular node + sinoatrial node in most patients. The posterior descending artery supplies the posterior third of the interventricular septum.

Electromagnetic waves are categorized according to their frequency or equivalently according to their wavelength. Visible light makes up a small part of the full electromagnetic spectrum.

Electromagnetic waves with shorter wavelengths and higher frequencies include ultraviolet light, X-rays, and gamma rays. Electromagnetic waves with longer wavelengths and lower frequencies include infrared light, microwaves, and radio and televisions waves.

Different electromagnetic waves according to their wavelength from shorter to longer are X-rays, ultraviolet radiations, visible light, infrared radiation, radio waves. X-ray among electromagnetic waves has the shortest wavelength and higher frequency with wavelengths ranging from 10*-8 to 10* -12 and corresponding frequencies.

Case control studies in particular are prone to recall bias, people who are suffering from COPD might sometimes relate the ailment to marijuana usage in past and hence contrary to the control group, they are more able to describe to what extent they have been using the drug in the past.

As recommended, all the doctors should make sure that there practice is based on evidence and thus it is paramount that the doctors learn to appraise the paper in a critical manner i.e. ability to detect any potential source of bias.

Detection Bias: Outcomes are more looked for in one group than the other.

Observer Bias: Subjectivity of observers regarding the outcome.

Publication bias: Not publishing the results of a valid study just because they are negative or uninteresting can be termed as publication bias.

Recall bias: Recall bias is specifically appropriate to the case control studies that is when ever the memories retrieved by the participants differ in accuracy.

Response Bias: The participants that filled out the response forms containing information that was going to be used for a trial, don’t represent the target population.

The body of the Entonox cylinder is usually blue (occasionally white), with blue and white shoulders. Entonox contains a 50:50 mixture of oxygen and nitrous oxide, with a full cylinder pressure of 13700 KPa (137 bar). The cylinder is equipped with a two-stage pressure regulator for safe operation.

The cylinder body and shoulder of nitrous oxide are (French) blue.

In today’s anaesthetic workstations, carbon dioxide cylinders are no longer used.

The body of an oxygen cylinder is black, with a white shoulder.

The white Heliox (21 percent oxygen and 79 percent helium) cylinder has a brown and white shoulder. The administration of this gas mixture, which is less dense than air, is used to reduce turbulence (stridor) of inspiratory flow in patients with upper airway obstruction.

There are different types of temperature measurement. These include:

Thermistor – this is a type of semiconductor, meaning they have greater resistance than conducting materials, but lower resistance than insulating materials. There are small beads of semiconductor material (e.g. metal oxide) which are incorporated into a Wheatstone bridge circuit. As the temperature increases, the resistance of the bead decreases exponentially

Thermocouple – Two different metals make up a thermocouple. Generally, in the form of two wires twisted, welded, or crimped together. Temperature is sensed by measuring the voltage. A potential difference is created that is proportional to the temperature at the junction (Seebeck effect)

Platinum resistance thermometers (PTR) – uses platinum for determining the temperature. The principle used is that the resistance of platinum changes with the change of temperature. The thermometer measures the temperature over the range of 200°C to1200°C. Resistance in metals show a linear increase with temperature

Tympanic thermometers – uses infrared radiation which is emitted by all living beings. It analyses the intensity and wavelength and then transduces the heat energy into a measurable electrical output

Gauge/dial thermometers – Uses coils of different metals with different co-efficient of expansion. These either tighten or relax with changes in temperature, moving a lever on a calibrated dial.

Ketamine is usually used as a racemic mixture, i.e. (R/S)-ketamine. For over 20 years, use of the more potent (S)-enantiomer by anaesthesiologists has become a preferred option due to the assumption of increased anaesthetic and analgesic properties, a more suitable control of anaesthesia, and of an improved recovery from anaesthesia.

The use of ketamine in anaesthesia and psychiatry may be accompanied by the manifestation of somatic and especially psychomimetic symptoms such as perceptual disturbances, experiences of dissociation, euphoria, and anxiety.

The incidence of a disease is the number of new cases of the disease in a population over a defined time period.

The prevalence of a disease is the number of cases of the disease in a population over a defined time period describes. It is NOT the number of new cases.

The number of new cases of a disease only, has no denominator (time period or population) from which to derive an incidence.

The number of new cases of a disease seeking medical treatment is the incidence of patients seeking medical treatment NOT the incidence of the disease in a population.

The death rate from a disease is the number of patients dying from the disease in a population.

Standard wire gauge cannulas for intravenous and intraarterial use are available (SWG or G). The SWG is a former imperial unit (which requires metric conversion). The cross sectional area of wires is becoming more popular as a size measurement.

The number of wires that will fit into a standard hole template is referred to as SWG.

This standard sized hole can accommodate 22 thin wires side by side (each wire the diameter of a 22 gauge cannula)
In the same hole, 14 thicker wires would fit (each wire the diameter of a 14 gauge cannula)

While the diameter and thus radius of a parallel sided tube are the most important determinants of fluid flow rate, they are not commonly used to compare cannula sizes.

The circumference of French gauge (FG) catheters (urinary or chest drains) is measured. Sizes of double lumen tracheal tubes are FG. Internal diameter is used to measure single lumen tubes.

The renal arteries branch from the abdominal aorta just below the origin of the superior mesenteric artery. The right renal artery is higher and longer than the left renal artery. The left renal artery passes behind the left renal vein, the body of the pancreas, and the splenic vein.

The important landmarks of vessels arising from the abdominal aorta at different levels of vertebrae are:

T10 – oesophageal opening in the diaphragm

T12 – Coeliac trunk, aortic hiatus in the diaphragm

L1 – Left renal artery

L2 – Testicular or ovarian arteries

L3 – Inferior mesenteric artery

L4 – Bifurcation of the abdominal aorta

The wall of an artery has three layers: (innermost to outermost)
1. Tunica intima – in direct contact with the blood inside the vessel and contains endothelial cells separated by gap junctions.
2. Tunica media – contains smooth muscle cells and is separated from the intima by the internal elastic lamina and the adventitia by the external elastic lamina.
3. Tunica adventitia – contains the vasa vasorum, fibroblast, and collagen.

Aortic dissection is when a tear arises in the innermost layer of the aorta and penetrates through the tear, entering the media layer. The inner and middle layers of the aorta split (dissect).

The femoral triangle is a wedge-shaped area found within the superomedial aspect of the anterior thigh. It is a passageway for structures to leave and enter the anterior thigh.

Superior: Inguinal ligament
Medial: Adductor longus
Lateral: Sartorius
Floor: Iliopsoas, adductor longus and pectineus

The contents include: (medial to lateral)
Femoral vein
Femoral artery-pulse palpated at the mid inguinal point
Femoral nerve
Deep and superficial inguinal lymph nodes
Lateral cutaneous nerve
Great saphenous vein
Femoral branch of the genitofemoral nerve

ARR= (Risk factor associated with the new drug group) — (Risk factor associated with the currently available drug)

So,

ARR= (10/400)-(20/400)

ARR= 0.025-0.05

ARR= 0.025 (Numerical Value)