Calcium channel blocker (CCB) blocks L-type of voltage-gated calcium channels present in blood vessels and the heart. By inhibiting the calcium channels, these agents decrease the frequency of opening of calcium channels activity of the heart, decrease heart rate, AV conduction, and contractility.

Three groups of CCBs include
1) Phenylalkylamines: Verapamil, Norverapamil
2) Benzothiazepines : Diltiazem
3) Dihydropyridine : Nifedipine, Nicardipine, Nimodipine, Nislodipine, Nitrendipine, Isradipine, Lacidipine, Felodipine and Amlodipine.

Even though verapamil as good absorption from GIT, its oral bioavailability is low due to high first-pass metabolism.

Nimodipine is a Cerebro-selective CCB, used to reverse the compensatory vasoconstriction after sub-arachnoid haemorrhage and is more lipid soluble analogue of nifedipine

Calcium channel antagonist can potentiate the effect of non-depolarising muscle relaxants.

The cardiac action potential has several phases which have different mechanisms of action as seen below:
Phase 0: Rapid depolarisation – caused by a rapid sodium influx.
These channels automatically deactivate after a few ms

Phase 1: caused by early repolarisation and an efflux of potassium.

Phase 2: Plateau – caused by a slow influx of calcium.

Phase 3 – Final repolarisation – caused by an efflux of potassium.

Phase 4 – Restoration of ionic concentrations – The resting potential is restored by Na+/K+ATPase.
There is slow entry of Na+into the cell which decreases the potential difference until the threshold potential is reached. This then triggers a new action potential

Of note, cardiac muscle remains contracted 10-15 times longer than skeletal muscle.

Different sites have different conduction velocities:
1. Atrial conduction – Spreads along ordinary atrial myocardial fibres at 1 m/sec

2. AV node conduction – 0.05 m/sec

3. Ventricular conduction – Purkinje fibres are of large diameter and achieve velocities of 2-4 m/sec, the fastest conduction in the heart. This allows a rapid and coordinated contraction of the ventricles

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 bispectral index (BIS) monitors works to determine the level of consciousness of a patient by processing electroencephalographic (EEG) signals to obtain a value between 0 and 100, where 0 reflects no brain activity, and 100 reflects a patient is completely awake.

The general meaning of BIS values are:

>95: Patient is in an awake state.
65-85: Patient is in a sedated state.
40-65: Patient is in a state that is optimal for general surgery.
<40: Patient is in a deep hypnotic state It is important in measuring the depths of anaesthesia to prevent haemodynamic changes or patient awareness during surgery. The nature of anaesthetic agent used is a determinant factor in resultant BIS values. Intravenous agents, such as propofol, thiopental and midazolam, result in a deeper hypnotic state, whilst inhalation agents have a lesser hypnotic effect at the same BIS values. Certain agents result in inaccurate BIS values such as ketamine and nitrous oxide (NO). These two agents appear to increase the BIS value, whilst putting the patient in a deeper hypnotic state, and should therefore not be used with BIS monitoring. Hypothermia also affects the BIS value as it causes a 1.12 per °C decrease in body temperature.

The static-response defines how a measuring system behaves while it is in equilibrium (i.e. when the measured values are not changing). If the value being measured changes over time, the reaction of a measuring system will change as well which would be a dynamic response.
The dynamic response of a measuring system can be subdivided into zero-order, first-order and second-order responses:

Zero-order:
Consider a thermometer that has been left in a room for a week. The thermometer will display the current ambient temperature when you enter the room.

First-order:
Consider the use of a mercury thermometer to check a patient’s temperature. It is comprised of a mercury column that expands as it warms up. The scale’s initial temperature is room temperature, but when it’s placed under the patient’s tongue, the temperature readings rise until they reach body temperature.

Second-order
Consider putting weights on a mechanical weighing scale. The weight as reported on the measuring dial, will wobble around the correct value at first until reaching equilibrium. An example of this is in clinical practice is the direct measurement of arterial pressure with a transducer. The value of the input fluctuates around a central point.

Drift is the progressive deterioration of a measurement system’s precision. With time, the measurement deviates from the genuine, calibrated value. The graph between this measurement and the real value should, ideally, be linear (e.g. on the y-axis the measured end-tidal CO2 against true value of the end-tidal CO2). Drift is split into three types: zero-offset, gradient, and zonal drift.

A forest plot is a graphical representation that summarizes the findings of several research, such as a meta-analysis of a series of randomized controlled trials.

The Kaplan-Meier estimate shows survival over time, for example, plotting the number of patients still alive seven years after chemotherapy for lung cancer.

Fisher’s exact test similarly uses contingency tables to assess statistical significance, however, it is typically used when sample sizes are small.

Chi-square test assesses whether an association exists between two categorical variables using the observed and expected frequencies. For instance, is social class (I-V) related to body mass index (BMI) category? Using the observed and anticipated frequencies, the Chi-square test determines whether a connection exists between two categorical variables. For example, is socio-economic status related to BMI category?

Linear regression is a technique which attempts to model the relationship between two variables by fitting a linear equation to observed data. Linear regression uses correlation between two continuous variables. As correlation only indicates the strength of an association only, it cannot be used to forecast the change in one variable when a second variable is altered.

This equation takes the form y = mx + c, where ‘y’ is the dependent variable, ‘x’ is the independent variable, ‘m’ is the slope of the line and ‘c’ is the intercept. In this example, for a range of heights, it would be possible to map a line of best fit to a scatter plot and thus predict the forced expiratory volume (FEV1) for an individual.

If the afterload and myocardiac contractility remains unchanged, an increase in the preload can be attributed to an increase in end-diastolic volume.

Preload can be defined as the initial stretching of the cardiac myocytes prior to contraction. Preload, therefore, is related to muscle sarcomere length. Because sarcomere length cannot be determined in the intact heart, other indices of preload are used such as ventricular end-diastolic volume or pressure. When venous return to the heart is increased, the end-diastolic pressure and volume of the ventricles are increased, which stretches the sarcomeres, thereby increasing their preload.

There are two types of defibrillators
AC defibrillator
DC defibrillator

AC defibrillator,
consists of a step-up transformer with primary and secondary winding and two switches. Since secondary coil consists of more turns of wire than the primary coil, it induces larger voltage. A voltage value ranging between 250V to 750V is applied for AC external defibrillator. And used to enable the charging of a capacitor.

DC defibrillator,
consists of auto transformer T1 that acts as primary of the high voltage transformer T2. Is an iron core that transfers energy between 2 circuits by electromagnetic induction. Transformers are used to isolate circuits, change impedance and alter voltage output. transformers do not convert AC to DC.

Diode rectifier composed of 4 diodes made of semiconductor material allows current to flow only in one direction. Alternating current (AC) passing through these diodes produces direct current (DC). Capacitor stores the charge in the form of an electrostatic field.

Capacitor is used to convert the rectified AC voltage to produce DC voltage but capacitors do not directly convert AC to DC.

Inductor induces a counter electromotive force(emf) that reduces the capacitor discharge value.

In step-down transformer primary coils has more turns of wire than secondary coil, so induced voltage is smaller in the secondary coil.

Erythromycin binds to the 50s subunit of bacterial rRNA complex and inhibits protein synthesis.

Gentamicin is a broad-spectrum antibiotic whose mechanism of action involves inhibition of protein synthesis by binding to 30s ribosomes. Its major adverse effect is nephrotoxicity and ototoxicity

Aminoglycoside bind to 30s subunit of ribosome causing misreading of mRNA

Tetracyclines inhibit protein synthesis through reversible binding to bacterial 30s ribosomal subunits, which prevent binding of new incoming amino acids (aminoacyl-tRNA) and thus interfere with peptide growth.

The patient’s diagnosis is microcytic hypochromic anaemia which is often as a result of iron deficiency and thalassaemia.

Macrocytic anaemia is often caused by folate and B12 deficiencies and alcohol abuse.

Normocytic normochromic anaemia is often caused by acute blood loss, haemolytic anaemia, anaemia of chronic disease and leucoerythroblastic anaemias.

Approximately 25% of phase-1 drug reactions is made responsible by CYP2D6.

As much as a 1,000-fold difference in the ability to metabolise drugs by CYP2D6 can happen between phenotypes, and this may result in adverse drug reactions (ADRs).

The metabolism of antiemetics, beta-blockers, codeine, tramadol, oxycodone, hydrocodone, tamoxifen, antidepressants, neuroleptics, and antiarrhythmics is also as a result of CYP2D6.

Patients who take drugs that are metabolised by CYP2D6 but have poor CYP2D6 metabolism are more likely to have ADRs. People with ultra-rapid CYP2D6 metabolism may have a decreased drug effect due to low plasma concentrations of these drugs.

All the other CYP enzymes are subject to genetic polymorphism. Variants are less likely to lead to adverse drug reactions.

The emulsification and absorption of fats requires Bile salts.

Absorption of fats is associated with the activation of lipases in the intestine.

Bile salts are involved in fat soluble vitamin absorption and are reabsorbed in the terminal ileum (B12 is NOT fat soluble).

Although Vitamin B12 is also absorbed in the terminal ileum, it is a water soluble vitamin (as are B1, nicotinic acid, folic acid and vitamin C) .

The gastric parietal cells secretes Intrinsic factor that is essential for the absorption of B12.

Ampicillin belongs to the family of penicillin. Resistance to this group of drugs is due to ?-lactamase production which 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.

Resistance to cephalosporins is due to changes in penicillin-binding proteins.

Resistance to macrolides are due to post-transcriptional methylation of 23s bacterial ribosomal RNA

Resistance to fluoroquinolones is due to mutations in DNA gyrase.

Classification of hemorrhagic shock according to Advanced Trauma Life Support is as follows:

– Class I haemorrhage (blood loss up to 15%) in which there is no change in blood pressure, RR, or pulse pressure.

– Class II haemorrhage (15-30% blood volume loss) where there is tachycardia, tachypnoea, and a decrease in pulse pressure.

– Class III haemorrhage (30-40% blood volume loss) where clinical signs of inadequate perfusion, marked tachycardia, tachypnoea, significant changes in mental state, and measurable fall in systolic pressure is seen. It almost always requires a blood transfusion.

– Class IV haemorrhage (> 40% blood volume loss) in which marked tachycardia, significant depression in systolic pressure and very narrow pulse pressure, and markedly depressed mental state with cold and pale skin are seen.

Loss of >50% results in loss of consciousness, pulse, and blood pressure.

The cardiac muscle’s contractile fibres have a much more stable resting potential than its conductive fibres. In the ventricular fibres it is -90mV and in the atrial fibres it is -80mV.

The cardiac action potential has several phases which have different mechanisms of action as seen below:

Phase 0: Rapid depolarisation – caused by a rapid sodium influx.
These channels automatically deactivate after a few ms. (QRS complex)

Phase 1: caused by early repolarisation and an efflux of potassium.

Phase 2: Plateau – caused by a slow influx of calcium.

Phase 3 – Final repolarisation – caused by an efflux of potassium.

Phase 4 – Restoration of ionic concentrations – The resting potential is restored by Na+/K+ATPase.
There is slow entry of Na+into the cell which decreases the potential difference until the threshold potential is reached. This then triggers a new action potential

Of note, cardiac muscle remains contracted 10-15 times longer than skeletal muscle.

Different sites have different conduction velocities:
1. Atrial conduction – Spreads along ordinary atrial myocardial fibres at 1 m/sec

2. AV node conduction – 0.05 m/sec

3. Ventricular conduction – Purkinje fibres are of large diameter and achieve velocities of 2-4 m/sec, the fastest conduction in the heart. This allows a rapid and coordinated contraction of the ventricles

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

Nitric oxide (NO), an endothelial-derived relaxant factor (EDRF), is a powerful vasodilator. Its cell-signalling molecule is calcium-dependant and generated endogenous by nitric oxide synthetases from the precursor L-arginine, oxygen and NADPH. Three main isoforms have been isolated and they are inducible (iNO), neuronal (nNO) and endothelial (eNO).

Endothelial NO stimulates intracellular guanylyl cyclase which generates cyclic GMP (cGMP) from its action on guanylyl tri-phosphate (GTP). The cGMP goes on to activate protein kinase G (PKG). PKG phosphorylates cell membrane proteins that regulate intracellular calcium concentrations and level of calcium sensitisation.

Smooth muscle vasodilatation results from:

1. Light chain phosphatase activation.
2. Inhibition of calcium entry into the cell (reducing Ca2+ concentrations) and
3. Hyperpolarisation of cells by activation of H+ channels.

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.

From superior to inferior, the following structures enter the orbit through the superior orbital fissure:
1. Lacrimal nerve
2. Frontal nerve
3. Superior ophthalmic vein
4. Trochlear nerve
5. Superior division of the oculomotor nerve*
6. Nasociliary nerve*
7. Inferior division of the oculomotor nerve*
8. Abducent nerve*
9. Inferior ophthalmic vein.

The superior and inferior division of the oculomotor nerve, nasociliary nerve, and abducent nerve are within the tendinous ring.

The common origin of the four rectus muscles is the tendinous ring (also known as the annulus of Zinn). The tendinous ring’s lateral portion straddles the superior orbital fissure, while the medial portion encloses the optic foramen, through which the optic nerve and ophthalmic artery pass.

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.

Haemorrhage, including intracranial bleeding, is a common and potentially fatal side effect of warfarin therapy, and reversing anticoagulation quickly and completely can save lives. When complete and immediate correction of the coagulation defect is required in orally anticoagulated patients with life-threatening haemorrhage, clotting factor concentrates are the only viable option.

For rapid reversal of vitamin K anticoagulants, prothrombin complex concentrates (PCC) are recommended. They contain the vitamin K-dependent clotting factors II, VII, IX, and X and are derived from human plasma. They can be used as an adjunctive therapy in patients with major bleeding because they normalise vitamin K dependent clotting factors and restore haemostasis.

The most common treatments are fresh frozen plasma (FFP) and vitamin K. The efficacy of this approach is questioned due to the variable content of vitamin K-dependent clotting factors in FFP and the effects of dilution. Significant intravascular volume challenge, as well as the possibility of rare complications like transfusion-associated lung injury or blood-borne infection, are all potential issues.

To avoid anaphylactic reactions, vitamin K should be given as a slow intravenous infusion over 30 minutes. Regardless of the route of administration, the reversal of INRs with vitamin K can take up to 24 hours to reach its maximum effect.

Reversal of anticoagulation in patients with warfarin-associated intracranial haemorrhage may be considered with factor VIIa (recombinant), but its use is controversial. There are concerns about thromboembolic events following treatment, as well as questions about assessing efficacy in changes in the INR. If the drug is to be administered, patients should be screened for an increased risk of thrombosis before the drug is given.

The patient is rebreathing carbon dioxide that has been exhaled.

Exhaustion of the soda lime and failure of the expiratory valve are the two most likely causes. A leak in the inspiratory limb is a less likely cause. Increased inhaled and exhaled carbon dioxide levels may appear with a normal-looking capnogram if the expiratory valve is ineffective.

The patient will exhale into both the inspiratory and expiratory limbs if the inspiratory valve is inoperable. A slanted downstroke inspiratory phase (as the patient inhales carbon dioxide-containing gas from the inspiratory limb) and increased end-tidal carbon dioxide can be seen on the capnogram.

Even if the soda lime were exhausted, a high fresh gas flow would be enough to prevent rebreathing. The difference in oxygen concentrations in inspired and expired breaths would be less pronounced.

Hypercapnia is caused by respiratory obstruction and malignant hyperthermia, but not by rebreathing.

Elimination of phenytoin from the body follows first-order kinetics. This means that the rate of elimination is proportional to plasma concentration.

The rate of elimination can be described by the equation:

C = C0·e-kt

Where:

C = drug concentration
C0 = drug concentration at time zero (extrapolated)
k = Rate constant
t = Time

Enzyme systems become saturated when phenytoin concentrations exceed the normal range and elimination of the drug becomes zero-order. At this point, the drug is metabolised at a fixed rate and metabolism is independent of plasma concentration.

Aspirin and ethyl alcohol are other drugs that behave this way.

Intra-arterial blood pressure monitoring is a common place procedure in the ICU. It is used to provide accurate beat-to-beat information using a pressure wave displayed on a monitor.

It involves catheter insertion in a peripheral artery (most commonly the radial, brachial and dorsalis pedis arteries). Each subsequent contraction of cardiac muscles results in pressure wave which induces a mechanical motion of flow in the catheter. This mechanical motion is then passed on to a transducer through a rigid fluid-filled tubing. The transducer is the able to process this mechanical motion into electrical signals which are displayed as arterial waves and pressure represented numerically on the monitor.

The transducer should be placed at the same level as the heart on the phlebostatic axis, and at the level of the atria (the 4th intercostal space, in the mid-axillary line).

Air bubbles and catheter tubing with longer lengths result in wave dampening (rounding of the resulting pressure waves). This dampening causes a decrease in systolic pressure, and an increase in diastolic pressure.

Monosynaptic reflexes is a type of reflex arc providing direct communication between motor and sensory innervation in a muscle. It occurs very quickly as it arises and ends in the same muscle. Examples include: biceps reflex, brachioradialis reflex, extensor digitorum reflex, triceps reflex, Achilles reflex and patellar reflex.

Polysynaptic reflexes facilitates contraction and inhibition in muscle by providing communication between multiple muscles.

Atrial natriuretic peptide (ANP) is secreted mainly from myocytes of right atrium and ventricle in response to increased blood volume.
It is secreted by both the right and left atria (right >> left).

It is a 28 amino acid peptide hormone, which acts via cGMP
degraded by endopeptidases.

It serves to promote the excretion of sodium, lowers blood pressure, and antagonise the actions of angiotensin II and aldosterone.

The SI unit of pressure is the pascal (Pa) and it is equal to one newton (N) per square meter (m2) or N/m2.

1 atmosphere (atm) is the equivalent of:

101325 Pa760 mmHg
1.01325 bar
1033.23 cmH2O.
14.69 pounds per square inch (psi)
1013.25 millibar (mbar) or hectopascals (hPa), and

14.69 psi is equal to one atmosphere. The other values are equal to two atmospheres of pressure.

Number needed to treat can be defined as the number of patients who need to be treated to prevent one additional bad outcome.

It can be found as:

NNT=1/Absolute Risk Reduction (rounded to the next integer since number of patients can be integer only).

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

So,

ARR= (43.9-37.3)

ARR= 6.6

NNT= 1000/6.6

NNT=151.5

The coeliac axis refers to one of the splanchnic arteries located within the abdomen.

It arises from the aorta almost horizontally at the level of the T12 vertebrae