Pharmacology for Dentistry

142 Section 3/ Drugs Acting on ANS

• Severe pulmonary hypertension


• Percardial tamponade


• Coarctation of aorta
  IV Distributive shock


• Anaphylaxis


• Septic shock


• Neurogenic shock


• Endocrinologic shock


• Due to toxic products e.g. overdose

TREATMENT

CARDIOGENIC SHOCK

It is characterized by severe, persisting
pain, shock and hypotension with possible
development of arrhythmias and is due to
severe depression of systolic cardiac
performance, systolic arterial pressure is
below 80 mm Hg, low cardiac index,
ventricular filling pressure is elevated and
pulmonary edema may or may not be
evident. The most frequent cause is
infarction involving more than fourty
percent of the left ventricular myocardiam,
leading to a severe reduction in left
ventricular contractility contradictively and
failure of the left ventricular pump.

Acute myocarditis and depression of
myocardial contractility following cardiac
arrest and prologed cardiac surgery also the
causes of cardiogenic shock.

Cardiogenic shock is also caused by
mechanical abnormalities of the ventricle.
Acute mitral or ventricular aneurysm,
usually caused by acute myocardial
infarction, can cause a severe reduction in
forward cardiac output and thereby result
in cardiogenic shock.

The management of cardiogenic shock
when it is due to myocardial infarction (after

mechanical causes have been excluded), the

therapy should be directed toward reducing

ischemia and salvaging severely, ischemic

but reversibly damaged myocardium at the

infart border. This may also be supported

by administration of oxygen and nitrates,

intraaortic balloon pumping and depending

upon the specific condition, thrombolytic

agents may be added.

The repaired myocardium may be treated

by combination of intraaoritc balloon

couterpulsation and sympathomimetics

amines e.g. dopamine, dobutamine, etc.

In other conditions of cardrogenic shock

(due to mechanical abnormalities) e.g. acute

mitral regurgitation or ventricular septal

defect, surgical correction is usually

required.

OLIGEMIC OR HYPOVOLEMIC SHOCK

It occur due to haemorrhage or a large

loss of body fluids secondary to diarrhoea,

vomiting, burn or dehydration leads to

inadequate ventricular filling i.e. to decreased

preload severely, decreased right and left

ventricular end-diastolic volumes and

pressures. These changes leads to oligemic

shock by causing an inadequate stroke

volume and inadequate cardiac output.

Oligemic shock may be managed by

rapid infusion of blood plasma or plasma

substitutes/expanders and simultaneously

the source of blood / fluid loss in identified

and corrected.

EXTRACARDIAC OBSTRUCTIVE

SHOCK

Pericardial temponade is the main cause

of extracardric obstructive shock, which is