Tell me the management of hypotension

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"Hypotension"[MeSH Terms] AND management

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adult hypotension emergency management guideline initial assessment fluids vasopressors

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https://pmc.ncbi.nlm.nih.gov/articles/PMC10389095/

Management of hypotension

Treat hypotension as an emergency if there are signs of poor perfusion: confusion, syncope, cold/clammy skin, chest pain, breathlessness, oliguria, rising lactate, or persistent systolic BP below about 90 mmHg. Call emergency services or obtain urgent senior/critical-care help.

Immediate approach: ABCDE

Airway and breathing
- Ensure airway patency.
- Give oxygen if hypoxaemic or in shock.
- Assist ventilation if respiratory failure, severe work of breathing, or reduced consciousness.
Circulation
- Place the patient supine and elevate legs temporarily if tolerated.
- Attach continuous monitoring: BP frequently or continuously, ECG, oxygen saturation, temperature, urine output.
- Obtain two large-bore IV cannulas. Send blood tests: CBC, electrolytes/renal function, glucose, lactate, blood gas, troponin where indicated, and crossmatch if bleeding is possible.
- Check bedside glucose and correct hypoglycaemia.
- Perform focused assessment for cause: bleeding, dehydration, sepsis, anaphylaxis, cardiac ischaemia/arrhythmia, pulmonary embolism, tamponade, pneumothorax, adrenal crisis, and drug toxicity. ECG and point-of-care ultrasound can help rapidly classify shock.
Fluid resuscitation, only when appropriate
- For likely volume depletion or distributive shock, give an IV crystalloid bolus, then reassess BP, lung findings, perfusion, urine output, and fluid responsiveness.
- A typical adult challenge is 500 mL crystalloid over 20-30 minutes. If major dehydration, haemorrhage, or sepsis is evident, larger initial volumes may be needed.
- Use smaller boluses, about 125-250 mL, with close reassessment if cardiogenic shock, pulmonary oedema, significant heart failure, or renal failure is possible. Uncontrolled fluid administration may worsen pulmonary oedema.
  Goldman-Cecil Medicine, IV Fluids section, lines 2465-2471.
If hypotension persists after appropriate fluid
- Start a vasopressor in a monitored setting. Norepinephrine is generally first line for distributive shock and is also commonly preferred in profound cardiogenic shock.
- Aim initially for a mean arterial pressure around 65 mmHg, then individualise according to baseline BP, mentation, urine output, lactate, and organ perfusion.
- Arrange critical-care involvement. An arterial line and central access may be needed, although vasopressor initiation should not be delayed solely to obtain central access.
Treat the underlying cause at the same time

Likely cause	Key treatment
Haemorrhage	Control external bleeding, activate major-haemorrhage protocol if appropriate, give blood products early, urgent surgery/endoscopy/interventional radiology as indicated.
Sepsis	Cultures where feasible without delaying treatment, early broad-spectrum IV antibiotics, IV crystalloids, source control, norepinephrine if still hypotensive. Textbook principles include oxygen, crystalloid, antibiotics, and vasopressors as needed. Frameworks for Internal Medicine, p. 300.
Anaphylaxis	IM epinephrine immediately in the outer thigh, airway/oxygen support, IV fluids, repeat epinephrine as needed. Antihistamines and steroids are adjuncts, not substitutes.
Cardiogenic shock	Urgent ECG/echo and cardiology input. Avoid routine large-volume fluids if congestion is present; use cautious fluid challenge only if underfilling is plausible. Revascularisation for acute MI, treat arrhythmia, vasopressor/inotrope as clinically indicated.
Obstructive shock	Treat the obstruction: needle decompression for tension pneumothorax, urgent pericardiocentesis for tamponade, reperfusion/thrombolysis or embolectomy for massive pulmonary embolism when indicated.
Medication-related or orthostatic hypotension	Stop or adjust precipitating drugs if safe, such as diuretics, nitrates, vasodilators, beta-blockers, sedatives, and adrenergic blockers; correct dehydration and review autonomic dysfunction.
Adrenal crisis	Give IV hydrocortisone and isotonic fluid promptly, correct hypoglycaemia/electrolytes, and treat the precipitant.

Ongoing reassessment

Recheck BP, mental state, capillary refill, skin temperature, urine output, lactate, and lung examination after every intervention.
Do not manage only the BP number. The priority is restoring tissue perfusion while avoiding fluid overload.
Admit patients with sustained, recurrent, unexplained, or symptomatic hypotension for evaluation.

A contemporary emergency-department review supports prompt recognition of shock, fluid resuscitation with balanced crystalloids when appropriate, norepinephrine for septic or profound cardiogenic shock, and cause-specific treatment, with ultrasound helping identify the shock type and fluid responsiveness (review in PMC).

Recent-evidence note: a 2025 systematic review (PMID 38870081) concerns intraoperative hypotension and does not replace this general emergency approach.

Help me to learn about pda according to what I know as a cardiac student

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"patent ductus arteriosus" AND treatment

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patent ductus arteriosus adult congenital heart disease guideline closure indications

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patent ductus arteriosus anatomy diagram left to right shunt

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PMID: 40548426

Patent ductus arteriosus (PDA): cardiac-student approach

1. Start with the normal fetal ductus

The ductus arteriosus is a normal fetal vascular channel between the proximal descending aorta and the left pulmonary artery.

In fetal life:

Pulmonary artery → ductus arteriosus → descending aorta

This bypasses the high-resistance fetal lungs. After birth, lung expansion lowers pulmonary vascular resistance and rising arterial oxygen tension plus reduced prostaglandin activity constrict the ductus. Functional closure normally occurs in the first few days, then it becomes the ligamentum arteriosum by about 12 weeks.
The Developing Human: Clinically Oriented Embryology, p. 880.

PDA means persistence of this channel beyond the normal neonatal transition.

2. The core haemodynamic idea

After birth, systemic vascular resistance is higher than pulmonary vascular resistance. Therefore, in usual PDA:

Aorta → pulmonary artery, producing a continuous left-to-right shunt.

Think of it as recirculation:

LV → aorta → PDA → pulmonary artery → lungs → LA → LV

So the principal chamber consequence is:

Increased pulmonary blood flow
Increased pulmonary venous return
Left atrial and left ventricular volume overload
Not initially RV volume overload, unlike ASD

The size of the shunt depends on:

Duct diameter and length
Pressure gradient between aorta and pulmonary artery
Pulmonary vascular resistance (PVR)

3. Clinical spectrum

Small or restrictive PDA

Usually asymptomatic
Normal pulses and no cardiomegaly
May be detected because of the characteristic murmur
Risk of infective endarteritis/endocarditis remains a reason to consider closure

Moderate PDA

Exertional dyspnoea, poor weight gain or recurrent chest infections in children
Bounding pulses
Wide pulse pressure
Left atrial and LV dilatation on echocardiography

Large PDA

Major left-to-right shunt
Pulmonary overcirculation and heart failure
In infants: tachypnoea, feeding difficulty, sweating while feeding, hepatomegaly, failure to thrive
May cause pulmonary hypertension

Long-standing large PDA

Pulmonary vascular disease may develop:

Left-to-right shunt → pulmonary hypertension → equalisation of pressures → right-to-left shunt

This is Eisenmenger physiology. At that point, closure can be dangerous because the PDA may be functioning as a pressure-relief pathway for the right heart.

4. Classical examination findings

Murmur

The classic finding is a continuous “machinery” murmur, best heard at the left upper sternal border, classically around the left second intercostal space.

Why continuous?
Aortic pressure exceeds pulmonary artery pressure in both systole and diastole, so flow through the duct persists throughout the cardiac cycle.

Other signs of a significant shunt:

Bounding or collapsing pulses
Wide pulse pressure
Hyperdynamic precordium
Apical diastolic flow murmur may occur if increased mitral flow is substantial
Signs of heart failure in large shunts

Important advanced sign: differential cyanosis

In PDA with Eisenmenger syndrome, deoxygenated blood enters the descending aorta distal to the branches to the head and upper limbs. Thus:

Lower limbs: cyanosis and clubbing
Upper limbs: relatively spared

This is called differential cyanosis/differential clubbing.

5. Investigations

Echocardiography with colour Doppler: first-line

It identifies:

The duct and direction of shunting
Ductal anatomy and size
LA/LV dilatation
Pulmonary artery pressure estimate
Associated defects
Flow reversal in descending aorta if shunt is large

Bailey and Love describes colour-flow Doppler echocardiography as the best confirmation test. Bailey and Love's Short Practice of Surgery, Patent ductus arteriosus section.

ECG

Small PDA: often normal
Moderate/large PDA: LA enlargement and LV hypertrophy/volume overload
Severe pulmonary hypertension: RV hypertrophy may appear

Chest radiograph

With significant PDA:

Cardiomegaly, mainly LA/LV enlargement
Pulmonary plethora
Prominent pulmonary arteries

Cardiac catheterisation

Not routine for a straightforward PDA in a child. It is useful when:

Pulmonary hypertension is suspected
PVR and operability need assessment
The anatomy is unclear
Adult PDA closure is being considered

Key numbers to know:

Qp:Qs quantifies pulmonary-to-systemic flow.
A significant left-to-right shunt is often considered at Qp:Qs ≥1.5:1, especially with LV volume overload.
PVR determines whether closure is safe.

6. PDA in preterm infants versus term infants

Preterm infant PDA

PDA is common because ductal smooth muscle and the postnatal closure response are immature.

A haemodynamically significant PDA may contribute to:

Pulmonary oedema and ventilator dependence
Systemic hypoperfusion
Feeding intolerance
Renal hypoperfusion
Potentially intraventricular haemorrhage or necrotising enterocolitis, although causation and ideal treatment remain debated

Management is individualised, based on clinical condition and echo findings. It may involve:

Conservative care: optimise ventilation, fluid management, and monitoring
Pharmacologic closure: ibuprofen, indomethacin, or sometimes paracetamol/acetaminophen
Transcatheter or surgical closure when clinically significant PDA persists despite appropriate medical management or medical treatment is unsuitable

Do not memorise “every preterm PDA needs immediate drug closure.” A 2025 Cochrane review of 19 RCTs found early treatment of haemodynamically significant PDA in preterm infants produced little or no difference in mortality or chronic lung disease compared with expectant management, supporting a selective rather than automatic treatment strategy (Cochrane review, PMID 40548426).

Term infant, child, or adult PDA

Spontaneous closure after infancy is uncommon. A persistent audible or haemodynamically meaningful PDA is usually closed, most often with a transcatheter occlusion device.

7. Indications and contraindication for closure

Close the PDA when there is:

Symptoms attributable to the shunt
LV volume overload or LV dilatation
A significant left-to-right shunt, commonly Qp:Qs ≥1.5
Prior infective endarteritis/endocarditis
An audible PDA, depending on institutional practice and anatomy
Suitable anatomy for device closure

Do not simply close every PDA in pulmonary hypertension

If there is severe, irreversible pulmonary vascular disease or established right-to-left shunting/Eisenmenger syndrome, closure is generally contraindicated.

The reasoning: closing the ductus removes the decompression route for the high-pressure pulmonary circuit and may precipitate right ventricular failure.

For adults with pulmonary hypertension, specialist congenital-heart-disease assessment, invasive PVR measurement, and sometimes test occlusion are needed. The ESC adult congenital guidance uses PVR to guide PDA closure decisions.

8. Treatment methods

1. Medical closure

Principally for preterm infants.

Indomethacin: COX inhibitor, reduces prostaglandin-mediated ductal patency
Ibuprofen: commonly used alternative
Paracetamol/acetaminophen: alternative in selected circumstances

Avoid or use with caution when there is:

Significant renal dysfunction
Thrombocytopenia/bleeding risk
Necrotising enterocolitis or major gastrointestinal risk
Certain contraindications to NSAIDs

2. Transcatheter device closure

This is preferred for most anatomically suitable PDAs beyond infancy.

Benefits:

No thoracotomy
High closure success
Short recovery

Complications to know:

Device embolisation
Residual shunt or haemolysis
Obstruction of the left pulmonary artery or descending aorta, especially in small infants
Vascular access complications

3. Surgical ligation/division

Used when:

Very small infant size limits device options
Anatomy is unsuitable
Catheter closure fails or is unavailable
PDA is managed during another cardiac operation

9. Exam comparison: PDA versus other shunts

Feature	PDA	ASD	VSD
Shunt level	Great-vessel level	Atrial level	Ventricular level
Usual shunt	Aorta to PA	LA to RA	LV to RV
Main volume-loaded chamber	LA and LV	RA and RV	LA and LV
Typical murmur	Continuous machinery	Ejection systolic with fixed split S2	Harsh pansystolic
Pulse pressure	Often wide in significant PDA	Usually normal	Usually normal
Eisenmenger clue	Differential cyanosis	Central cyanosis	Central cyanosis

10. High-yield viva answers

What is PDA?
Persistent patency after birth of the fetal communication between the descending aorta and the left pulmonary artery.

What is the usual shunt direction?
Left-to-right, from aorta to pulmonary artery.

Why is the murmur continuous?
The aorta remains at higher pressure than the pulmonary artery during both systole and diastole.

Which chambers enlarge?
Left atrium and left ventricle, due to increased pulmonary venous return.

Why are pulses bounding?
Runoff from the aorta into the low-resistance pulmonary circulation lowers diastolic pressure, creating wide pulse pressure.

What is differential cyanosis?
Cyanosis and clubbing of the lower limbs with relatively spared upper limbs in PDA with Eisenmenger physiology.

What is the usual definitive treatment?
Transcatheter device closure if the PDA is haemodynamically significant and pulmonary vascular disease is not irreversible.

When should PDA not be closed?
In established irreversible pulmonary hypertension with right-to-left shunting/Eisenmenger physiology, unless an expert congenital team determines otherwise.

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