Episode 6B - Bonus Episode! Deep Dive into Dyspnoea, PART 2

1.The GP hook

Part two of our dyspnoea series gets hands-on: simple, fast T-POCUS decisions, what normal looks like, when to suspect asthma or DKA, and which treatments to reach for in the first hour—without tipping patients over the edge.

Part two of our dyspnoea deep dive goes practical: finish T‑POCUS, read the glide sign, treat the “clean scan” cat, spot FATE fast and choose safe first‑hour moves—keeping the patient on the right side of the edge.

If you’ve ever faced a loudly breathing cat beside a silent lateral x‑ray machine, you know the moment. Oxygen on, nurse at the door, probe in your hand… and your brain asking, “Wet lung, air, heart, or something pretending to be lung?” This episode finishes the focused point‑of‑care ultrasound (T‑POCUS) checklist and walks through what to do when scans are normal, what diagnostics to grab fast, and which treatments to consider in that critical first hour.

2.Finish T‑POCUS: pneumothorax and the glide sign

Common trap: seeing B‑lines then hunting for a glide in the same spot. If B‑lines are present, pneumothorax is very unlikely there.

• Don’t panic if you can’t nail pneumothorax at first — it’s subtle and not that common. Practice.
• Key rule: if you see B‑lines at your probe site, you don’t have pneumothorax there. Air between lung and chest wall reflects the ultrasound beam; B‑lines won’t appear across an air layer.
• The glide sign:
• Look for a bright pleural line between ribs that shimmers with respiration. Think “ants marching” or a glittering pleural line.
• A completely static line is suspicious for pneumothorax.
• If unsure, scan ventrally on the same side: air rises, so you may lose dorsal glide but retain ventral glide.
• Practical tip: in trauma, mark where the glide returns (Sharpie) to track progression or to guide where to tap.
• Don’t overtrust T‑FAST for pneumothorax; if the patient is severely dyspnoeic or trauma suggests it, a rapid DV radiograph or needle thoracocentesis may still be needed.

3.Cardiac T‑POCUS without tears: LA:Ao and “is it squeezing?”

• In emergency T‑POCUS you’re not doing full echo. The two questions are:
• Is the left atrium enlarged relative to the aorta (LA:Ao)?
• Is contractility roughly adequate?
• Practical LA:Ao hints:
• Probe just caudal to the right elbow and fan cranially to find the aortic cross‑section (“Mercedes” sign).
• In many dyspnoeic cats with cardiogenic pulmonary oedema the LA is obvious — often you don’t need measurements.
• Contractility:
• A visual assessment is often sufficient. Markedly poor contraction is usually obvious and clinically useful.
• Positioning tips:
• Draw the right forelimb forward and nudge the patient a small amount so the heart falls closer to the chest wall — tiny angle changes can transform an image.
• If you can, scan a few calm normals to learn what “normal” looks like. It makes spotting abnormal much easier.

4.When T‑POCUS is “normal”: airways, parenchyma and look‑alikes

• A clean T‑POCUS doesn’t mean “nothing wrong.” Think:
• Airway disease (feline asthma), which often has a long cough history and can be mistaken by owners for “furballing.”
• Diffuse parenchymal disease (neoplasia, fibrosis) that won’t be visible on ultrasound if there’s no superficial fluid — air reflects the beam.
• Systemic look‑alikes: DKA cats hyperventilate to compensate for metabolic acidosis; pyrexia, hyperthermia or panic can also sound scary.
• Quick bedside checks:
• If clean POCUS + heavy breathing: ask about cough history, seasonality and “furball” episodes → think asthma.
• If clean POCUS + malaise or polyuria/polydipsia: check blood glucose, ketones and basic biochemistry → think DKA.
• If noisy but the patient’s been stressed/fighting outside, settle in oxygen and reassess—many calm down.

5.Saddle thrombus (FATE): recognise fast, act with context

• Classic signs: sudden hindlimb paresis/anaesthesia with severe pain, cold hind feet with absent femoral pulses, and low rectal temperature.
• Most FATE cats you’ll see have a markedly enlarged LA on T‑POCUS; sometimes you’ll even visualise spontaneous echocontrast (“smoke”).
• Practical approach:
• If both hindlimbs are cold, pulseless and anaesthetic with low rectal temp — FATE is likely.
• If limbs are warm and nociception present after trauma, consider spinal/neurological causes.
• Management is very case‑dependent. Discussion with the owner about prognosis, breathing status and likely hospital course is essential; many severe, dyspnoeic cats face a poor prognosis and euthanasia is often considered as part of shared decision‑making, but milder unilateral cases may be managed with intensive care when appropriate.

6.Quick diagnostics that change decisions

Clinical pearl: If the heart on ultrasound looks like it’s “buzzing” (very rapid mechanical activity), confirm with ECG — you might be staring at an arrhythmia.

• Blood pressure: cheap, quick and useful. Bear in mind device limitations and white‑coat effects — persistent extreme values are more meaningful than a single borderline reading.
• Minimum database from a tiny IV sample can give PCV/TS, glucose, lactate, BUN and a smear — rapid, decision‑shaping data.
• Blood gases: arterial gas best reflects oxygenation but may not be practical. Venous blood gas + clinical picture is often informative in emergencies.
• ECG: a short lead II (10–20 s) can flip management — look for rhythm, very fast or slow rates and ventricular‑looking beats. Rapid tachyarrhythmias can be missed on auscultation alone.

7.First‑hour treatments you’ll actually use (practical caveats)

• Cardiogenic pulmonary oedema:
• Use IV diuretics as the core immediate therapy. In very sick patients repeat boluses more frequently until response is seen, then space them out. Verify doses and regimens against current guidelines and your local formulary before use.
• Be mindful of renal function and of potassium trends after aggressive diuresis; check bloods when feasible.
• Consider switching diuretic class if response is inadequate; this typically signals more advanced disease and needs clear owner counselling.
• Pimobendan can help appropriate cases (e.g. certain mitral valve disease or poor contractility), but avoid if you suspect left ventricular outflow tract obstruction. Discuss costs and expectations with owners.
• Pleural effusion and pyothorax:
• Thoracocentesis is both diagnostic and therapeutic — send fluid for cytology/culture where possible.
• Pyothorax commonly requires repeated drainage and often chest drains; warm saline lavages can help loosen thick pus. Plan and consent early for intensive care when needed.
• Trauma and pulmonary contusions:
• Treat what you see. Contusions are bruising — stabilise shock but avoid excessive fluid rates thereafter to prevent worsening lung oedema.
• Not all traumatic pneumothoraces need immediate drainage; intervene based on respiratory compromise.
• Feline asthma (acute):
• IV or IM bronchodilator therapy and systemic steroids are used in emergencies; inhaled bronchodilators via spacer can supplement if tolerated. Confirm specific agent choices and dosing with current references before use.
• Aspiration pneumonia (including BOAS‑prone dogs):
• Start appropriate IV antibiotics guided by hospital policy and culture where possible. Check local guidelines for agent choice and dosing frequency.
• Upper airway obstruction and BOAS crisis:
• Opioid sedation (e.g. butorphanol) can help some patients; many require more support.
• Medetomidine (careful patient selection and monitoring) can break the panic cycle in selected non‑cyanotic patients; plan airway backup.
• If cyanotic or failing, induction and intubation with controlled ventilation (propofol CRI commonly used in hospital) may be lifesaving. Consider a sedative/analgesic plan for the extubation/recovery window to avoid immediate recurrence.

8.Radiographs: when, how — and when not

• Lateral radiographs can tip a dyspnoeic patient over. Prioritise oxygen, T‑POCUS and stabilisation.
• If imaging is needed and tolerated, a DV view in sternal is safer than lateral for many dyspnoeic patients.
• If POCUS already demonstrates pleural effusion, wet lungs or frank pneumothorax, treat first and image later if the result would change management.

9.Practical scanning and team flow

• Small ergonomic tricks: pull the right elbow forward, tilt the patient a whisker so the heart falls to the chest, use a nurse to freeze or steady the patient.
• “Good enough to decide” beats “perfect image” in an emergency. Document what you can without delaying care.
• Build a one‑page T‑POCUS checklist for nurse‑vet pairs: roles, views to prioritise, when to mark the chest, and triggers to escalate to ECG, bloods or thoracocentesis.

10.The calm flow in dyspnoea

Oxygen. Minimise stress. Observe. T‑POCUS. Decide. Treat. Then add tests that change decisions. If your focused scan is clean, think airways, invisible parenchymal disease or systemic look‑alikes (DKA, hyperthermia, panic). When it’s cardiac you’ll often know fast: wet lungs with an enlarged LA or poor squeeze. Treat the pattern in front of you and keep an eye on kidneys, electrolytes and patient comfort.

Closing takeaway

A quick, calm T‑POCUS + basic diagnostics and good team choreography will change most dyspnoea cases. Practice the normal views, mark what you find, and focus treatment on the confirmed pattern — the perfect image can wait; breathing can’t.

If you want clarification on any of these approaches or a follow‑up on a case example, get in touch — we’ll tackle it on the next episode.

Bonus material

Bonus material – managing hyperthermia in brachycephalics