Moderately high doses of dopamine produce a positive inotropic (direct?1 and D1 action + that due to Noradrenaline release), but the little chronotropic effect on the heart.

Vasoconstriction (?1 action) occurs only when large doses are infused.

At doses normally employed, it raises cardiac output and systolic BP with little effect on diastolic BP. It has practically no effect on nonvascular ? and ? receptors; does not penetrate the blood-brain barrier—no CNS effects.

The neuroleptic malignant syndrome (NMS) is a rare complication in response to neuroleptic or antipsychotic medication.

The main features are:
– Elevated creatinine kinase
– Hyperthermia and tachycardia
– Altered mental state
– Increased white cell count
– Insidious onset over 1-3 days
– Extrapyramidal dysfunction (muscle rigidity, tremor, dystonia)
– Autonomic dysfunction (Labile blood pressure, sweating, salivation, urinary incontinence)

Management is supportive of ICU care, anticholinergic drugs, increasing dopaminergic activity with Amantadine, L-dopa, and dantrolene, and non- depolarising neuromuscular blockade drugs.

Since Olanzapine is a potential cause of NMS it is not a treatment.

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

The fibrotendinous ring formed by the congregation of the rectus muscles at the apex of the orbit does not include superior oblique. This muscle is completely outside the ring and so it is the most difficult muscle to anaesthetise completely. A good grasp of the anatomy of the area being anaesthetised is important with all regional anaesthetic techniques so that potential problems and complications with a block can be anticipated.

The borders of this pyramid whose apex points upwards and outwards of the bony orbit are as follows:
Floor – Zygoma and Maxilla
Roof – frontal bone
Medial wall – maxilla, ethmoid, sphenoid and lacrimal bones.
Lateral wall – greater wing of the sphenoid and the zygoma.

The four recti muscles (superior, medial, lateral and inferior) originate from a tendinous ring (the annulus of Zinn) and extend anteriorly to insert beyond the equator of the globe. Bands of connective tissue are present between the rectus muscles forming a conical structure and hinder the passage of local anaesthetic.

The superior oblique muscle is situated outside this ring and is the most difficult muscle to anaesthetise completely, particularly with a single inferotemporal peribulbar injection. An additional medial injection may help to prevent this.

The cranial nerve supply to the extraocular muscles are:
3rd (inferior oblique, inferior recti, medial and superior)
4th (superior oblique), and
6th (lateral rectus).

The long and short ciliary nerves provide the sensory supply to the globe and these are branches of the nasociliary nerve, (which is itself a branch of the ophthalmic division of the trigeminal nerve).

To achieve anaesthesia for the eye, these nerves which enter the fibrotendinous ring need to be fully blocked to anaesthetise the eye for surgery.

The relative risk (also known as risk ratio [RR]) is the ratio of risk of an event in one group (e.g., exposed group) versus the risk of the event in the other group (e.g., nonexposed group).

The odds ratio (OR) is the ratio of odds of an event in one group versus the odds of the event in the other group.

Once the decision to deliver a baby by caesarean section has been made, it should be carried out with a level of urgency commensurate with the risk to the baby and the mother’s safety.

There are four types of caesarean section urgency:

Category 1 – Endangering the life of the mother or the foetus
Category 2 – Maternal or foetal compromise that is not immediately life threatening
Category 3 – Early delivery is required, but there is no risk to the mother or the foetus.
Category 4: Elective delivery at a time that is convenient for both the mother and the maternity staff.

Caesarean sections for categories 1 and 2 should be performed as soon as possible after the decision is made, especially for category 1. For category 1 caesarean sections, a decision to deliver time of 30 minutes is currently used.

In most cases, Category 2 caesarean sections should be performed within 75 minutes of making the decision.

The condition of the woman and the unborn baby should be considered when making a decision for a quick delivery, as it may be harmful in some cases.

There is no evidence of foetal compromise in the example above (early foetal pulse decelerations and a pH of less than 7.25). Early foetal pulse decelerations are most likely caused by the uterus compressing the foetal head. The foetus is not harmed by these. A spinal anaesthetic is preferred over a general anaesthetic whenever possible.

If the foetal scalp blood pH is greater than 7.25, it’s a good idea to repeat the test later and look for any changes. When a foetus decelerates, the mother should be given oxygen, kept in a left lateral position, and kept hydrated to avoid the need for a caesarean section.

Iliacus, and Psoas major are the most important muscles that produce flexion at the hip.

They are collectively called the iliopsoas muscle. The iliacus muscle originates from the ilium while the psoas major muscle takes its origin from the lumbar vertebrae and sacrum. Their insertion is the lesser trochanter of the femur. They work together to produce flexion and external rotation of the hip. The nerve supply is from branches of the lumbar plexus (L1, 2, 3) femoral nerve (L2, 3, 4) and short direct muscular branches (T12, L1, L2, L3 and L4).

Sartorius, Rectus femoris, Tensor fasciae latae, and Pectineus muscles are two-joint muscles acting at the knee and having less influence on hip flexion:

Rectus femoris and sartorius are involved in extension of the knee. They are supplied by branches of the femoral nerve.

Myotomes associated with key movement of the lower limb are:

L1/L2 – Hip flexion
L2/L3/L4 – Hip adduction, quadriceps (knee extension)
L4/L5 – Hip abduction
L5 – Great toe dorsiflexion.

Since knee extension is not affected, L2, L3 and L4 are still intact.

Pipeline gases (in the UK this includes: Oxygen, Nitrous oxide, Medical air, and Entonox) are supplied at 4 bar (or 400 kPa), and compressed air is supplied at 7 bar for power tools.

Carbon dioxide and nitric oxide are usually only supplied in cylinders.

Dorsal column (ascending tract) – Proprioception, vibration, discriminative

Spinocerebellar (ascending tract) – Subconscious muscle position and tone

Corticospinal (descending tract) – Voluntary muscle

Rubrospinal (descending tract) – Flexor muscle tone

Vestibulospinal (descending tract) – Reflexes and muscle tone

Reticulospinal(descending tract) – Voluntary movements, head position.-

Autonomic – Descending tract.

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.