7.3 Maternal Shock States: Hemorrhagic, Distributive, Cardiogenic & Obstructive
Key Takeaways
- Maternal shock states are classified pathophysiologically into four distinct categories: Hemorrhagic (hypovolemic, driven by massive blood loss), Distributive (septic, anaphylactic, or neurogenic, driven by pathologically reduced systemic vascular resistance), Cardiogenic (pump failure from peripartum cardiomyopathy, myocardial infarction, or myocarditis), and Obstructive (physical impediment to cardiac filling or outflow from massive pulmonary embolism, tension pneumothorax, or cardiac tamponade).
- Normal maternal physiology (a 40-50% expansion in blood volume and baseline resting tachycardia) masks early hypovolemic shock; classic signs such as hypotension and marked tachycardia often do not appear until class III hemorrhage (>30% blood volume loss, or >1,500 mL), necessitating reliance on the Shock Index (Heart Rate / Systolic Blood Pressure; SI >=0.9 indicates critical hypoperfusion) for early detection.
- Norepinephrine is the first-line vasopressor for septic and distributive shock in pregnancy (titrated to maintain MAP >=65 mmHg to preserve maternal organ and uteroplacental perfusion), whereas Epinephrine is the primary drug of choice for anaphylaxis (0.3 to 0.5 mg IM into the anterolateral thigh) and cardiac arrest, and Dobutamine or Milrinone serve as first-line inotropes for acute cardiogenic shock with preserved blood pressure.
- Obstructive shock etiologies represent procedural and surgical emergencies requiring immediate, etiology-specific decompression: emergent needle/finger thoracostomy for tension pneumothorax, urgent bedside subxiphoid pericardiocentesis for cardiac tamponade, and systemic thrombolysis (Alteplase 50 to 100 mg IV) or catheter-directed embolectomy for massive saddle pulmonary embolism with acute right heart strain.
- Multimodal hemodynamic assessment—incorporating invasive arterial line monitoring, central venous pressure, point-of-care cardiac and lung ultrasound (POCUS/FoCUS), and advanced non-invasive cardiac output monitoring—is essential to accurately differentiate preload deficiency, contractile failure, systemic vasodilation, and RV outflow obstruction in undifferentiated maternal shock.
Maternal Shock States: Hemorrhagic, Distributive, Cardiogenic & Obstructive
Shock is defined as an acute, life-threatening state of circulatory failure resulting in inadequate cellular oxygen delivery ($DO_2$) relative to cellular oxygen consumption ($VO_2$). When cellular oxygen demands are unmet, tissues shift from aerobic respiration to anaerobic glycolysis, generating systemic lactic acidosis, cellular dysoxia, ATP depletion, loss of membrane integrity, and progressive multi-organ dysfunction syndrome (MODS).
In pregnant patients, physiological adaptations significantly alter baseline hemodynamic parameters, frequently obscuring classic early signs of shock until sudden, catastrophic decompensation occurs.
1. Pathophysiologic Foundation & The Obstetric Shock Index
The Maternal Physiological "Mask"
During pregnancy, maternal blood volume increases by 40% to 50% (approx. 1,500 mL), baseline cardiac output rises by 30% to 50%, systemic vascular resistance (SVR) decreases, and baseline resting heart rate increases by 10 to 15 bpm.
Because of this hypervolemic reserve, a gravid woman can lose 1,000 to 1,500 mL of blood (up to 30% of total blood volume) before developing overt arterial hypotension (systolic BP <90 mmHg). Compensatory maternal vasoconstriction maintains normal systemic blood pressure while shunting blood away from the uterine circulation. Consequently, fetal distress on fetal monitoring (persistent decelerations, bradycardia) is frequently the earliest indicator of maternal hypoperfusion and occult shock!
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| THE OBSTETRIC SHOCK INDEX (SI) |
| |
| Heart Rate (HR in beats per minute) |
| Shock Index (SI) = ---------------------------------------- |
| Systolic Blood Pressure (SBP in mmHg) |
| |
| • Normal Non-Pregnant & Healthy Pregnant Range: **0.5 to 0.7** |
| • Mild Elevation / Early Warning Threshold: **0.7 to 0.9** |
| • CRITICAL CLINICAL THRESHOLD: **SI >= 0.9** |
| - Strongly predicts severe blood loss (>1,500 mL), Massive Transfusion Protocol (MTP) |
| activation, intensive care unit (ICU) admission, and emergent surgical intervention. |
| • DECOMPENSATED SHOCK THRESHOLD: **SI >= 1.4** |
| - Indicates profound circulatory collapse, impending cardiac arrest, and >40% volume loss. |
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2. The Four Major Maternal Shock Taxonomies
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| MATERNAL SHOCK CLASSIFICATION MATRIX |
| |
| 1. HEMORRHAGIC / HYPOVOLEMIC SHOCK: |
| • Primary Defect: Depleted intravascular circulating volume (decreased preload). |
| • Obstetric Causes: Postpartum hemorrhage (atony 70%, PAS, lacerations, rupture, abruption), |
| ectopic pregnancy rupture, subcapsular liver hematoma rupture. |
| |
| 2. DISTRIBUTIVE SHOCK: |
| • Primary Defect: Pathological systemic vasodilation & capillary leak (severely decreased SVR)|
| • Obstetric Causes: Septic shock (chorioamnionitis, pyelonephritis, Group A Strep), |
| Anaphylactic shock (beta-lactams, latex, iron), Neurogenic shock (high spinal/epidural). |
| |
| 3. CARDIOGENIC SHOCK: |
| • Primary Defect: Primary myocardial contractile / pump failure (severely decreased CI / CO). |
| • Obstetric Causes: Peripartum cardiomyopathy (PPCM), Spontaneous coronary artery dissection |
| (SCAD), acute myocardial infarction (AMI), myocarditis, severe valvular decompensation. |
| |
| 4. OBSTRUCTIVE SHOCK: |
| • Primary Defect: Physical mechanical barrier to cardiac filling or outflow. |
| • Obstetric Causes: Massive pulmonary embolism (PE), tension pneumothorax, cardiac tamponade, |
| severe dynamic aortocaval compression. |
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A. Hemorrhagic / Hypovolemic Shock in Obstetrics
Obstetric hemorrhage remains the most prevalent cause of maternal shock globally. Staging based on estimated blood loss and hemodynamic parameters guides resuscitation:
| Hemorrhage Class | Blood Loss (% and mL) | Heart Rate (bpm) | Blood Pressure | Shock Index | Mental Status & Urine Output | Clinical Action & Transfusion Protocol |
|---|---|---|---|---|---|---|
| Class I | <15% (<750–1000 mL) | Normal (<100) | Normal | <0.7 | Alert; Normal (>30 mL/hr) | Uterotonics, crystalloid maintenance, monitor closely. |
| Class II (Mild) | 15–30% (1000–1500 mL) | Mild tachycardia (100–110) | Normal / Orthostatic | 0.7–0.9 | Mild anxiety; 20–30 mL/hr | Type & crossmatch, active uterotonics, TXA 1 g IV, prepare blood. |
| Class III (Moderate) | 30–40% (1500–2000 mL) | Tachycardia (110–130) | Hypotension (SBP <90) | 0.9–1.4 | Agitated / Confused; Oliguria (5–15 mL/hr) | Activate MTP (1:1:1), Cryoprecipitate, TXA 1 g IV, intrauterine balloon / surgery. |
| Class IV (Severe) | >40% (>2000 mL) | Severe (>130 / bradycardia) | Profound (<70 mmHg) | >1.4 | Lethargic / Comatose; Anuria (<5 mL/hr) | Emergent surgical hemostasis / Damage control laparotomy / MTP. |
B. Distributive Shock: Sepsis, Anaphylaxis & Neurogenic
1. Obstetric Septic Shock
Sepsis in pregnancy arises from intra-amniotic infection (chorioamnionitis), postpartum endometritis, acute pyelonephritis, septic abortion, or soft-tissue necrotizing fasciitis (e.g., Streptococcus pyogenes / Group A Strep, Escherichia coli).
- Diagnosis: Validated obstetric screening tools include the Sepsis in Obstetrics Score (S.O.S.) and the Obstetric-Modified Sequential Organ Failure Assessment (omSOFA) score.
- Surviving Sepsis Hour-1 Care Bundle:
- Measure serum lactate level (re-measure if initial lactate >2 mmol/L).
- Obtain blood cultures prior to antibiotic administration (two sets from distinct venipuncture sites).
- Administer broad-spectrum empiric IV antibiotics within 1 hour (e.g., Ampicillin-Sulbactam 3 g IV + Gentamicin 5 mg/kg, or Meropenem 1 g IV + Vancomycin 15–20 mg/kg for septic shock).
- Rapid IV crystalloid administration: 30 mL/kg of balanced crystalloid (Lactated Ringer's) within the first 3 hours for hypotension or lactate >=4 mmol/L.
- Vasopressors: Initiate Norepinephrine infusion to maintain Mean Arterial Pressure (MAP) >=65 mmHg if hypotension persists after initial fluid loading.
2. Maternal Anaphylactic Shock
Anaphylaxis during labor and delivery is commonly triggered by intravenous beta-lactam antibiotics (cefazolin, ampicillin), latex, neuromuscular blocking agents (succinylcholine, rocuronium), intravenous iron infusions, or uterotonics.
- Clinical Manifestations: Acute cutaneous signs (urticaria, pruritus, flushing, angioedema) combined with rapid respiratory compromise (stridor, severe bronchospasm) and profound distributive cardiovascular collapse.
- First-Line Pharmacological Protocol:
- Epinephrine 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1,000 [1 mg/mL] solution) Intramuscularly (IM) into the anterolateral thigh immediately! Repeat every 5 to 15 minutes if symptoms persist.
- Refractory Shock: Initiate continuous IV Epinephrine infusion (0.05 to 0.5 mcg/kg/min).
- Secondary Adjuncts (Administer ONLY AFTER Epinephrine): Rapid crystalloid bolus (1–2 L LR), Diphenhydramine 50 mg IV (H1 blocker), Famotidine 20 mg IV (H2 blocker), and Methylprednisolone 125 mg IV.
3. Neurogenic Shock (High / Total Spinal Block)
Occurs from cephalad spread of local anesthetic agents following spinal or epidural administration, blocking sympathetic preganglionic fibers (T1 to L2).
- Manifestations: Profound systemic vasodilation and hypotension paired with paradoxical bradycardia (loss of cardiac accelerator fibers T1–T4) and warm, flushed skin.
- Management: Rapid crystalloid IV bolus, Left Uterine Displacement, Ephedrine 5 to 10 mg IV boluses (mixed alpha/beta agonist increases both HR and SVR), Phenylephrine 50 to 100 mcg IV (if heart rate is elevated), and Epinephrine 10 to 50 mcg IV if pulseless or profound bradycardia occurs.
C. Cardiogenic Shock in Pregnancy
Cardiogenic shock occurs when primary pump failure results in inadequate forward cardiac output (Cardiac Index <2.2 L/min/m2) despite adequate intravascular volume and ventricular filling pressure (PCWP >15–18 mmHg).
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| MAJOR CAUSES OF MATERNAL CARDIOGENIC SHOCK |
| |
| 1. PERIPARTUM CARDIOMYOPATHY (PPCM): |
| • Idiopathic heart failure with Left Ventricular Ejection Fraction (LVEF) <45% presenting |
| in the last month of pregnancy or first 5 months postpartum in the absence of prior heart |
| disease. Triggered by anti-angiogenic 16-kDa prolactin cleavage fragments (vasoinhibin). |
| • Pharmacotherapy: Inotropes (Dobutamine, Milrinone), Bromocriptine (2.5 mg daily for 1-4 wks |
| to inhibit prolactin secretion), anticoagulation (high thromboembolism risk when EF <35%). |
| |
| 2. SPONTANEOUS CORONARY ARTERY DISSECTION (SCAD) & ACUTE MI: |
| • Pregnancy hormones and vascular shear stress cause non-atherosclerotic intramural hematoma |
| and dissection, predominantly affecting the Left Anterior Descending (LAD) coronary artery. |
| • Management: Conservative medical therapy preferred; avoid aggressive stenting unless flow is|
| completely occluded. Inotropes and mechanical circulatory support for shock. |
| |
| 3. ACUTE MYOCARDITIS & DECOMPENSATED VALVULAR DISEASE: |
| • Viral myocarditis, severe mitral stenosis with pulmonary edema, or severe aortic stenosis. |
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D. Obstructive Shock: Mechanical Blockades
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| OBSTRUCTIVE SHOCK ETIOLOGIES & IMMEDIATE INTERVENTIONS |
| |
| 1. MASSIVE PULMONARY EMBOLISM (PE): |
| • Mechanism: Saddle thrombus occludes >50% of pulmonary arterial tree, triggering acute RV |
| dilation, failure, and obstructive cardiogenic collapse. |
| • Emergency Treatment: Systemic Thrombolysis (**Alteplase / tPA 50 to 100 mg IV infusion over |
| 2 hours**, or 50 mg IV bolus during cardiac arrest) OR catheter-directed thrombectomy. |
| |
| 2. TENSION PNEUMOTHORAX: |
| • Mechanism: Positive intrapleural pressure compresses the lung, shifts the mediastinum, and |
| completely collapses the superior and inferior vena cava, abolishing venous return. |
| • Emergency Treatment: **Immediate Needle Decompression** (14-gauge catheter in 2nd intercostal|
| space midclavicular line or 4th/5th intercostal space anterior axillary line) or emergent |
| **Finger Thoracostomy**, followed immediately by 28-32 Fr chest tube thoracostomy. |
| |
| 3. CARDIAC TAMPONADE: |
| • Mechanism: Pericardial fluid under pressure prevents diastolic ventricular filling. |
| • Classic Triad (Beck's Triad): Hypotension, Jugular Venous Distension, Muffled Heart Sounds. |
| • Emergency Treatment: **Immediate Bedside Ultrasound-Guided Subxiphoid Pericardiocentesis**. |
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3. Comprehensive Hemodynamic Parameter & Profile Comparison
Understanding the distinctive hemodynamic fingerprint of each shock category is essential for making precise clinical diagnoses at the bedside:
| Shock Category | Preload: RV (CVP) | Preload: LV (PCWP) | Pump Function: (CO / CI) | Afterload: (SVR) | Afterload: (PVR) | Mixed Venous Oxygen (ScvO2) | Primary Pathophysiologic Mechanism & Echo Findings |
|---|---|---|---|---|---|---|---|
| Hemorrhagic (Hypovolemic) | Decreased (<4 mmHg) | Decreased (<6 mmHg) | Decreased (<2.0 L/min/m2) | Increased (>1400 dynes) | Normal / Decreased | Decreased (<65%) | Intravascular volume depletion; compensatory vasoconstriction. Hyperdynamic, small, underfilled ventricles (kissing walls). |
| Distributive (Septic - Early / Warm) | Normal / Decreased | Normal / Decreased | Increased (>3.5 L/min/m2) | Severely Decreased (<600 dynes) | Normal | Increased (>75–80%) | Vasomotor paralysis and endothelial leak; hyperdynamic LV contractility, warm extremities, widened pulse pressure. |
| Distributive (Late / Cold Sepsis) | Variable | Variable | Decreased (<2.2 L/min/m2) | Variable / Normal | Increased | Decreased (<65%) | Myocardial depression and profound capillary leak; cool mottled extremities. |
| Distributive (Anaphylactic) | Decreased | Decreased | Variable / Decreased | Severely Decreased (<500 dynes) | Increased (bronchospasm) | Decreased | Massive histamine/tryptase mediated vasodilation and capillary fluid extravasation. |
| Cardiogenic (PPCM / MI) | Elevated (>12–15 mmHg) | Markedly Elevated (>18 mmHg) | Severely Decreased (<1.8 L/min/m2) | Increased (>1500 dynes) | Elevated | Severely Decreased (<55%) | Primary pump failure; dilated LV, severely reduced ejection fraction (<45%), pulmonary congestion/B-lines. |
| Obstructive (Massive PE) | Markedly Elevated (>15 mmHg) | Normal / Decreased (<10 mmHg) | Severely Decreased (<1.8 L/min/m2) | Increased | Severely Elevated (>300 dynes) | Decreased (<60%) | RV outflow obstruction; massive RV dilation, McConnel's sign, D-sign, underfilled LV. |
| Obstructive (Tamponade) | Markedly Elevated (>15 mmHg) | Markedly Elevated (Equalized) | Severely Decreased (<1.8 L/min/m2) | Increased | Normal / Elevated | Decreased (<60%) | Ventricular diastolic filling restriction; equalized diastolic pressures (CVP = PCWP = RV diastole), swinging heart. |
4. Vasoactive & Inotropic Pharmacology in Pregnancy
Selecting vasoactive pharmacotherapy in pregnancy requires balancing maternal hemodynamic stabilization against potential uteroplacental vasoconstriction. Maternal perfusion takes absolute precedence—restoring maternal Mean Arterial Pressure (MAP) is the single most important determinant of uterine blood flow during shock.
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| MATERNAL VASOACTIVE & INOTROPIC PHARMACOLOGY |
| |
| 1. NOREPINEPHRINE (First-Line Vasopressor for Septic / Distributive Shock): |
| • Receptor Profile: Alpha-1 (++++), Beta-1 (++), Beta-2 (0). |
| • Infusion Dose: 0.02 to 0.5 mcg/kg/min (titrate to MAP >=65 mmHg). |
| • Actions: Potent peripheral vasoconstriction restores SVR while modest inotropy preserves CO.|
| • Maternal-Fetal Impact: Restoring maternal perfusion pressure increases uteroplacental |
| blood flow; first-line drug of choice in maternal septic shock. |
| |
| 2. EPINEPHRINE (First-Line for Anaphylaxis & Cardiac Arrest; Inotrope in Refractory Shock): |
| • Receptor Profile: Beta-1 (++++), Beta-2 (+++), Alpha-1 (++++ at higher doses). |
| • Dosing: Anaphylaxis: 0.3 to 0.5 mg IM; Cardiac Arrest: 1 mg IV q3-5min; |
| Shock Infusion: 0.02 to 0.3 mcg/kg/min IV. |
| • Actions: Powerful chronotrope, inotrope, peripheral vasoconstrictor, and bronchodilator. |
| |
| 3. VASOPRESSIN (Second-Line / Adjunct Vasopressor): |
| • Receptor Profile: V1 vascular receptors (++++), V2 renal receptors. |
| • Fixed Infusion Dose: 0.03 to 0.04 units/min IV (do not titrate). |
| • Actions: Non-adrenergic vasoconstriction, highly effective during profound acidosis. |
| • Pulmonary Vascular Sparing: Causes systemic vasoconstriction with selective pulmonary |
| vasodilation (lowers PVR/SVR ratio); excellent adjunct in septic shock and RV failure. |
| |
| 4. PHENYLEPHRINE (Pure Alpha-1 Vasopressor): |
| • Receptor Profile: Alpha-1 (+++++), Zero Beta activity. |
| • Dosing: Bolus: 50 to 100 mcg IV; Infusion: 0.5 to 2.0 mcg/kg/min. |
| • Actions: Pure systemic vasoconstriction. Can cause reflex bradycardia and reduce cardiac |
| output. Drug of choice for post-spinal hypotension in awake, non-shocked cesarean patients. |
| |
| 5. DOBUTAMINE (First-Line Inotrope for Pure Cardiogenic Shock): |
| • Receptor Profile: Beta-1 (++++), Beta-2 (++), Minimal Alpha. |
| • Infusion Dose: 2.5 to 20 mcg/kg/min IV. |
| • Actions: Increases myocardial contractility and heart rate; induces mild peripheral |
| vasodilation (reduces afterload). First-line inotrope for PPCM with adequate MAP. |
| |
| 6. MILRINONE (Inodilator for RV Failure & Pulmonary Hypertension): |
| • Mechanism: Phosphodiesterase-3 (PDE3) inhibitor. |
| • Infusion Dose: 0.25 to 0.75 mcg/kg/min IV (omit loading bolus). |
| • Actions: Increases myocardial contractility while relaxing pulmonary and systemic vascular |
| smooth muscle; ideal for biventricular failure with elevated PVR. Must combine with |
| Norepinephrine if MAP is low. |
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5. Bedside Hemodynamic Monitoring & Echocardiography (POCUS / FoCUS)
In the modern obstetric critical care unit, Point-of-Care Ultrasound (POCUS) and Focused Cardiac Ultrasound (FoCUS) provide instantaneous diagnostic clarity for undifferentiated maternal shock:
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| POCUS RAPID EVALUATION ALGORITHM IN MATERNAL SHOCK |
| |
| 1. INFERIOR VENA CAVA (IVC) COLLAPSIBILITY (Subcostal View): |
| • Small, Collapsible IVC (<1.5 cm diameter, >50% inspiratory collapse): |
| -> Indicates HYPOVOLEMIC / HEMORRHAGIC or EARLY DISTRIBUTIVE SHOCK. Responds to fluids/blood.|
| • Plethoric, Distended IVC (>2.1 cm diameter, <50% inspiratory collapse): |
| -> Indicates CARDIOGENIC or OBSTRUCTIVE SHOCK (RV failure, massive PE, tamponade). |
| -> CRYSTALLOID FLUID BOLUSES ARE STRICTLY CONTRAINDICATED! |
| |
| 2. LEFT VENTRICULAR (LV) CONTRACTILITY (Parasternal Long & Short Axis Views): |
| • Hyperdynamic LV with small end-systolic cavity (kissing papillary muscles): |
| -> Hypovolemic or Distributive (Septic/Anaphylactic) shock. |
| • Dilated, Globally Hypokinetic LV with reduced Fractional Shortening / Ejection Fraction: |
| -> Cardiogenic shock (PPCM, SCAD, myocarditis). |
| |
| 3. RIGHT VENTRICULAR (RV) STRAIN & INTERDEPENDENCE (Apical 4-Chamber View): |
| • RV Dilation (RV:LV basal diameter ratio >1.0) + Interventricular Septal Flattening (D-sign):|
| -> Acute Cor Pulmonale from Massive Pulmonary Embolism or Amniotic Fluid Embolism. |
| • McConnell's Sign: Hyperdynamic RV apex with akinesia/hypokinesia of the RV mid-free wall. |
| -> Highly specific for Massive Pulmonary Embolism. |
| |
| 4. PERICARDIAL SPACE EVALUATION: |
| • Anechoic fluid collection surrounding myocardium + Right Atrial systolic collapse / |
| Right Ventricular diastolic collapse: |
| -> CARDIAC TAMPONADE -> Perform STAT Ultrasound-Guided Pericardiocentesis! |
| |
| 5. LUNG ULTRASOUND (BLUE Protocol): |
| • A-lines (Horizontal artifacts) with normal lung sliding: Normal aerated lung. |
| • Multiple B-lines ('Lung Rockets' >=3 per intercostal space bilaterally): Alveolar-interstitial|
| edema (Cardiogenic pulmonary edema vs ARDS). |
| • Absence of Lung Sliding + Presence of 'Lung Point': PATHOGNOMONIC FOR PNEUMOTHORAX. |
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A 24-year-old G1P0 at 36 weeks of gestation with acute chorioamnionitis exhibits persistent arterial hypotension (blood pressure 76/40 mmHg, Mean Arterial Pressure 52 mmHg) and a serum lactate of 4.2 mmol/L following the rapid infusion of 30 mL/kg of Lactated Ringer's solution. Which of the following vasoactive agents represents the first-line pharmacotherapeutic choice to restore maternal systemic vascular resistance and organ perfusion?
A 30-year-old G2P1 at 39 weeks of gestation receives an intravenous infusion of cefazolin for surgical prophylaxis prior to scheduled cesarean delivery. Two minutes into the infusion, she develops diffuse urticaria, facial angioedema, inspiratory stridor, severe wheezing, and profound hypotension with a blood pressure of 60/30 mmHg. Which immediate intervention takes absolute priority?
A 36-year-old G3P2 on postpartum day 2 following an uncomplicated vaginal delivery develops acute severe dyspnea, pleuritic right-sided chest pain, and syncope. Vital signs show a heart rate of 138 bpm, blood pressure of 72/40 mmHg, respiratory rate of 34 breaths/min, and SpO2 of 81% on room air. Bedside echocardiogram demonstrates severe right ventricular enlargement, McConnell's sign, and a plethoric, non-collapsible inferior vena cava. What is the most appropriate definitive emergency therapy for this patient's obstructive shock state?
A 32-year-old patient on postpartum day 14 presents to the emergency department with severe progressive orthopnea, bilateral lower extremity edema, and fatigue. Blood pressure is 98/62 mmHg, heart rate is 112 bpm, and oxygen saturation is 88% on room air. Bedside echocardiogram reveals a dilated left ventricle with a Left Ventricular Ejection Fraction (LVEF) of 25%, an elevated PCWP of 24 mmHg, and a reduced cardiac index of 1.7 L/min/m2. Bilateral diffuse B-lines are present on lung ultrasound. What is the primary diagnosis and the most appropriate inotropic agent for hemodynamic support?