Cyanosis medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Initial management of neonantal cyanosis
- Newborns with cyanosis require adequate tissue perfusion and oxygenation.
- A hyperoxia test is a test that is performed to determine whether the patient's cyanosis is due to lung disease or a problem with blood circulation. It is performed by measuring the arterial blood gases of the patient while they breathe room air, then re-measuring the blood gases after the patient has breathed 100% oxygen for 10 minutes.
- An infant who fails the hyperoxia test and does not have persistent pulmonary hypertension of the newborn or a chest radiograph consistent with lung disease is likely to have a cyanotic CHD.
- Monitoring of oxygen level and tissue perfusion is necessary.
- An adequate airway should be established immediately, mechanical ventilation may be needed in case of failed spontaneous respiration.
- Initiating oxygen therapy with 40–60% O2 is sufficient. Exposures to hyperoxia increases oxidative stress and damage lung parenchymal and vascular function.
- Placement of secure intravenous and intraarterial catheters is most easily accomplished via the umbilical vessels.
- Inotropic agents such as dopamine or dobutamine may be necessary to correct hypotension.
- An isovolumetric partial exchange transfusion should be performed with saline to reduce the hematocrit in cases of severe polycythemia.
- Maintenance a blood glucose > 55 mg/dL should be considered.
- Acidosis should be corrected with infusions of sodium bicarbonate.
- Hypocalcemia should be corrected based on the ionized calcium.
- Broad spectrum antibiotics should be initiated (ampicillin and gentamicin).
Prostaglandins
- In case of a minimal response to oxygen, cardiac disease should be suspected and need for PGE1 should be discussed.
- Closure of the ductus arteriosus can precipitate rapid clinical deterioration with significant life-threatening changes. It may increase pulmonary blood flow and decrease systemic blood flow.
- Interventions are initiated to maintain patency of the ductus arteriosus for ductal-dependent lesions.
- The initial dose is dependent on the clinical setting, as the risk of apnea.
- If the ductus is known to be large in a patient with duct-dependent physiology, the initial dose is 0.01 mcg/kg per minute.
- If the ductus is restrictive or the status of the ductus is unknown, the initial dose is 0.05 mcg/kgper minute.
- The dose of prostaglandin can be increased as needed to a maximum dose of 0.1 mcg/kg per minute.
- Complications of prostaglandin E1 infusion include hypotension, tachycardia, and apnea.
Respiratory distress syndrome
Surfactant therapy
- Exogenous surfactant replacement therapy is effective in reducing RDS mortality and morbidity in preterm infants [27-30].
Types of surfactant
- It may be natural or synthetic surfactants.
- Natural surfactants have been shown to be more efficient with lower inspired oxygen concentration and ventilator pressures, decreased mortality, and lower rate of RDS complications in preterm infants. [3,33,34]
- Poractant alfa: Porcine lung minced extract
- Calfactant: Bovine lung lavage extract
- Beractant: Bovine lung minced extract
Indications
All patients with RDS, and intubate and administer surfactant to those with persistent severe respiratory distress (defined as requiring a fraction of inspired oxygen [FiO2] of 0.40 or higher to maintain oxygen saturation above 90 percent) or who are apneic (algorithm 1) [1-3].
Response to initial dose
Additional doses of surfactant therapy are administered if the patient has a persistent requirement of an FiO2 >0.30. Subsequent surfactant administration may decrease mortality and morbidity in infants less than 30 weeks gestation with RDS [27,39]. (See 'Management approach' below and "Mechanical ventilation in neonates", section on 'Indications for ventilation'.)
If the infant maintains adequate respiratory efforts and has an FiO2 requirement less than 0.30, no additional doses of surfactant are needed and the patient can be extubated to nCPAP [27,39].
Timing
If surfactant therapy is used, it is most effective when given within the first 30 to 60 minutes of life following placement of a pulse oximeter and clinical confirmation of correct endotracheal tube placement. However, the potential benefits of timely administration of surfactant must be balanced with adequate time for an initial trial of nCPAP [27,40,41].
Endotracheal administration
Endotracheal intubation has been the standard technique of surfactant administration. However, surfactant administration may be complicated by transient airway obstruction [3,42] or inadvertent instillation into only the right main stem bronchus if the endotracheal tube is advanced too far in the airway. During administration, oxygen saturation needs to be monitored, as oxygen desaturation may occur. Other complications associated with intubation and mechanical ventilation include pulmonary injury due to volutrauma and barotrauma associated with intermittent positive pressure ventilation, pulmonary air leak, and airway injury due to intubation. (See 'Endotracheal tube complications' below.)
Ebstein's anomaly
- Control of the heart rhythm with antiarrhythmic drugs: Ebstein's anomaly may present with an AV nodal reentrant tachycardia with associated pre-excitation. Among these patients, the preferred pharmacological treatment agent is procainamide. Since AV-blockade may promote conduction over the accessory pathway, drugs such as beta blockers, calcium channel blockers and digoxin are contraindicated. If there is atrial fibrillation with pre-excitation, treatment options include procainamide, flecainide, propafenone, dofetilide and ibutilide since these medications slow conduction in the accessory pathwaycausing the tachycardia and should be administered before considering electrical cardioversion. Intravenous amiodarone may also convert atrial fibrillation and/or slow the ventricular response.
- Inotropic agents and diuretics for heart failure.
- Anticoagulation in patients with atrial fibrillation and paradoxical embolization Tricuspid valve repair is indicated in patients in which there is symptoms or deteriorating exercise capacity, cyanosis (oxygen saturation less than 90%), paradoxical embolism, progressive cardiomegaly on chest x-ray or progressive right ventricular dilation or reduction of right ventricular systolic function. When possible, repair is favored over replacement. Warfarin is recommended for patients with Ebstein’s anomaly with a history of paradoxical embolus or atrial fibrillation.
Coarctation of aorta
Preoperative
- Beta blockers are the treatment of choice.
- Caution should be taken as too much control of hypertension in upper limb can cause hypotension in lower limbs.
- Surgical treatment of the lesion should not be delayed for the correction of hypertension.
Postoperative
- Immediate post operative hypertension - use short-term vasodilators for e.g. sodium nitroprusside, or intravenous beta-blockers like esmolol.
- Long-term antihypertensive post surgery
- Monotherapy with beta-blockers
- ACE inhibitors or angiotensin II antagonists may be added if hypertension continues with beta-blocker monotherapy.
Eisenmenger syndrome
- If surgical intervention is not available, treatment is mostly palliative
- Anticoagulants
- Pulmonary vasodilators such as bosentan
- PGE 5 inhibitor
- Prostacyclin may improve pulmonary artery pressure and may improve length of life
- Antibiotic prophylaxis to prevent endocarditis
- Phlebotomy to treat polycythemia
- Maintaining proper fluid balance
- These measures can prolong lifespan and improve quality of life
Methemoglobinemia
Methemoglobinemia is treated with supplemental oxygen and methylene blue 1% solution (10mg/ml) 1-2mg/kg administered intravenously slowly over five minutes followed by IV flush with normal saline. Methylene blue restores the iron in hemoglobin to its normal (reduced) oxygen-carrying state. This is achieved through the enzyme inducing effect of methylene blue on levels of diaphorase II (NADPH methemoglobin reductase). Diaphorase II normally contributes only a small percentage of the red blood cells reducing capacity but is pharmacologically activated by exogenous cofactors, such as methylene blue, to 5 times its normal level of activity. Genetically induced chronic low-level methemoglobinemia may be treated with oral methylene blue daily.
Peripheral cyanosis treatment
Raynaud's phenomenon
- Drug treatment is normally with a calcium channel blocker, frequently nifedipine to prevent arterioconstriction. It has the usual side effects of headache, flushing, and ankle edema, and patients often stop treatment, preferring the symptoms of Raynaud's to the symptoms of the drug.
- The extract of the Ginkgo biloba leaves (Egb 761, 80mg) reduces symptoms in two weeks.
- There is some evidence that Angiotensin II receptor antagonists (often Losartan) reduce frequency and severity of attacks.
- In intractable cases, sympathectomy and infusions of prostaglandins, e.g. prostacyclin, may be tried, with amputation in exceptionally severe cases.
- Alpha-1 adrenergic blockers such as prazosin can be used to control Raynaud's vasospasms under supervision of a health care provider.
- In a study published in the November 8, 2005 issue of Circulation, sildenafil (Viagra) improved both microcirculation and symptoms in patients with secondary Raynaud's phenomenon resistant to vasodilatory therapy. The authors, led by Dr Roland Fries (Gotthard-Schettler-Klinik, Bad Schönborn, Germany), report: "In the present study, capillary blood flow was severely impaired and sometimes hardly detectable in patients with Raynaud's phenomenon. Sildenafil led to a more than 400% increase of flow velocity."
- Two separate gels combined on the fingertip (somewhat like two-part epoxy, they cannot be combined before use because they will react) increased blood flow in the fingertips by about three times. One gel contained 5% sodium nitrite and the other contained 5% ascorbic acid. The milliliter of combined gel covered an area of ~3 cm². The gel was wiped off after a few seconds. Tucker, A.T. et al., The Lancet, Vol. 354, November 13, 1999, pp..
Peripheral vascular disease
- Urgent measures should be taken to ensure blood flow and protect the limb:
- ICU admission
- Administration of heparin for anticoagulation
- Electrolytes, acid- base and renal status monitoring
- Limb status monitoring and frequent assessment of the need for fasciotomy.
- If the limb is not immediately threatened:
- Continue treatment with thrombolytic therapy for 14 days.
- If the limb ischemia is critical:
- Consider percutaneous transluminal angioplasty
- Consider surgery: thromboembolectomy, bypass grafting
- Send sample for pathologic examination (myxoma may be present)
Exercise rehabilitation
- A regular walking program four times a week for six month results in an average of 6.5 minutes improvement in the walking time.
- It opens up collateral circulation.
- It reduces cardiovascular mortality.
- It improves quality of life.
Cilostazol
- Cilostazol is a phosphodiesterase III inhibitor.
- It is FDA approved.
- Cilostazol is not administered to all PAD cases but rather to selected cases where regular walking program has failed to improve the walking time and capacity.
- It is contraindicated in congestive heart failure.
- Side effects:
- Headache
- Diarrhea
- Gastric upset
- Palpitations
- Dizziness
Endovascular Revascularization Modalities
- PTAC
- Stents
- Atherectomy
- Laser
- Cutting balloons
- Thermal angioplasty
- Fibrinolysis/Fibrinectomy