PULMONARY HYPERTENSION
Section snippets
DEFINITION
Pulmonary hypertension comprises a family of disorders occurring as a primary disease or as a complication of numerous systemic, cardiac, or pulmonary conditions. The normal pulmonary artery pressure at sea level ranges from a peak systolic volume of 18 to 25 mm Hg and a mean value ranging from 12 to 16 mm Hg. Pulmonary hypertension is defined as a resting pulmonary artery systolic or mean pressure exceeding 30 mm Hg or 20 mm Hg, respectively.
PATHOPHYSIOLOGY
The pulmonary circulation must be able to provide blood flow that is matched to the air supply. The normal pulmonary circulation is a low pressure system with remarkably low resistance that can accommodate large increases in blood flow with only slight increases in pulmonary artery pressure. A fourfold increase in blood flow (CO) during exercise is accompanied by a doubling of mean pulmonary artery pressure through recruitment and dilation of vessels.53 The increase in pulmonary capillary wedge
RESPONSE TO FACTORS
The pulmonary circulation is particularly sensitive to reduction in alveolar oxygen tension, and it appears that the resulting pulmonary vasoconstriction is important as a local compensatory mechanism to regional ventilation/perfusion imbalances.46 The response to hypoxia appears to be both age and species dependent. Young people appear to have an exaggerated response that diminishes with aging. The global response to alveolar hypoxia and resulting increase in PVR can be demonstrated in
PRIMARY PULMONARY HYPERTENSION
Primary pulmonary hypertension (PPH) is a condition defined by sustained elevation of pulmonary artery pressure without a demonstrable cause. The incidence ranges between 1 to 2 cases per 1 million people in the general population.63 A similar clinical picture can occur in patients with portal hypertension,20 human immunodeficiency virus (HIV) infection,49 or a history of cocaine inhalation,65 and in those taking appetite suppressant medications.1
Familial PPH is inherited as an autosomal
DIAGNOSIS
The diagnosis of PPH is complicated by the nonspecific nature of the symptoms and subtlety of the signs of less advanced disease. The mean interval from the onset of symptoms to diagnosis is about 2 years in PPH.56 In about 10% of patients, however, the diagnosis is delayed until after 3 years of symptoms.56 The most common presenting symptom for seeking medical advice is the development of dyspnea. The median period of survival after diagnosis, as reported in the National Institutes of Health
SECONDARY PULMONARY HYPERTENSION
The incidence of secondary pulmonary hypertension is far more common than that of PPH and results from an identifiable cause. A classification based on hemodynamic causes is given in Table 1. Cardiac disorders produce pulmonary hypertension by increasing the resistance to pulmonary venous drainage or pulmonary blood flow. The increased resistance to pulmonary venous drainage may arise from various disorders but is most commonly seen in patients exhibiting left-sided valvular disorders (aortic
Nitric Oxide
The discovery of endogenous nitric oxide production evolved from studies of the role of the endothelium in modulating vascular tone. Furchgott and Zawadzki25 observed that vascular rings relaxed only if the endothelium was intact. The vasodilator effects were the result of an endothelium substance (EDRF) that diffused into the smooth muscle and caused smooth muscle relaxation. In 1987, two groups independently showed that EDRF and nitric oxide were the same substance.31, 46 Nitric oxide is a
ANESTHESIA MANAGEMENT
The anesthetic management of patients with pulmonary hypertension presents a clinical challenge because the normal physiologic changes that accompany anesthesia and surgery can result in acute increases in PVR, leading to right ventricular failure. The increased morbidity and mortality with anesthesia and surgery have been well documented.9, 15, 42 Maternal mortality in Eisenmenger's syndrome and PPH exceeds 50%.76 The risks associated with PPH are more frequent than those related to secondary
SUMMARY
Considerable progress has been made in the treatment and anesthetic management of patients with pulmonary hypertension. Preoperative pulmonary vasodilator testing can provide an estimation of risk and provide therapeutic options in the perioperative period. Further advances in understanding of the pathologic process as well as new pharmacologic options will further improve the anesthesiologist's approach to this difficult group of disorders.
References (76)
- et al.
Inhaled nitric oxide and hemodynamic evaluation of patients with pulmonary hypertension before transplantation
J Am Coll Cardiol
(1995) - et al.
Influence of preoperative pulmonary artery pressure on mortality after heart transplantation: Testing of potential reversibility of pulmonary hypertension with nitroprusside is useful in defining a high risk group
J Am Coll Cardiol
(1992) - et al.
Coexistent pulmonary and portal hypertension: Morphologic and clinical features
J Am Coll Cardiol
(1987) - et al.
Comparison of the effects of isoflurane with those of propofol on pulmonary vascular impedance in experimental embolic pulmonary hypertension
Br J Anaesth
(1997) - et al.
Effects of oxygen breathing on pulmonary vascular input impedance in patients with pulmonary hypertension
Chest
(1983) - et al.
The human preproendothelin-1 gene: Complete nucleotide sequence and regulation of expression
J Biol Chem
(1989) - et al.
Adverse hemodynamic and clinical effects of calcium channel blockade in pulmonary hypertension secondary to obliterative pulmonary vascular disease
J Am Coll Cardiol
(1984) - et al.
Inhaled nitric oxide as a cause of selective pulmonary vasodilatation in pulmonary hypertension
Lancet
(1991) - et al.
Prostaglandin E2 and prostacyclin inhibit the production and secretion of endothelin from cultured endothelial cells
J Biol Chem
(1994) - et al.
Magnitude and implications of spontaneous hemodynamic variability in primary pulmonary hypertension
Am J Cardiol
(1985)
Primary pulmonary hypertension
Chest
Pulmonary hypertension associated with long-term inhalation of “crank” methamphetamine
Chest
Hemodynamic effects of inhaled nitric oxide in heart failure
J Am Coll Cardiol
Inhaled nitric oxide in patients with normal and increased pulmonary vascular resistance after cardiac surgery
Br J Anaesth
Cyanotic congenital heart disease and pregnancy: Natural selection, pulmonary hypertension, and anesthesia
J Clin Anesth
Appetite-suppressant drugs and the risk of primary pulmonary hypertension. International Primary Pulmonary Hypertension Study Group
N Engl J Med
Elevated pulmonary vascular resistance and cardiac transplantation
Circulation
Coagulation and fibrinolytic parameters in patients with pulmonary hypertension
Clin Cardiol
Thoracic epidural anaesthesia and primary pulmonary hypertension
Anaesthesia
Epidural anesthesia for cesarean section in a patient with severe pulmonary hypertension
Acta Anaesthesiol Scand
Cardiac output and related measurements and pressure values in the rigid heart and associated vessels, together with an analysis of the hemodynamic response to the inhalation of high oxygen mixture in healthy subject
J Lab Clin Med
A comparison of continuous intravenous epoprostenol (prostacyclin) with conventional therapy for primary pulmonary hypertension. The Primary Pulmonary Hypertension Study Group
N Engl J Med
Pulmonary hypertension in children: Perioperative management
Can Anaesth Soc J
Primary pulmonary hypertension with death during right heart catheterization: A case report and a survey of reported fatalities
Am J Cardiol
Isoflurane and primary pulmonary hypertension
Anaesthesia
Correlation of anatomic pulmonary emphysema and right ventricular hypertrophy
Am Rev Respir Dis
The nature of pulmonary hypertension in mitral stenosis
Br Heart J
Epidural anaesthesia for vascular surgery in a patient with primary pulmonary hypertension
Anaesth Intensive Care
Contribution of the endothelium to the response to anoxia in the canine femoral artery
Arch Int Pharmacodyn Ther
Impairment of endothelium-dependent pulmonary artery relaxation in chronic obstructive lung disease
N Engl J Med
Improved evaluation of pulmonary vascular resistance prior to heart transplantation
Transplant Proc
Endothelium and growth factors in vascular remodeling of hypertension
Hypertension
Hypoxia on the pulmonary circulation: How and where it acts
Circ Res
Pulmonary circulation
ACCP-NHLBI national conference on oxygen therapy
Chest
The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine
Nature
The effect of ketamine on pulmonary artery pressure
Anaesthesia
Acute right ventricular failure after pulmonary hypertensive responses to airway instrumentation: Effect of fentanyl dose
Anesthesiology
Cited by (2)
Simultaneous repair of bilateral multiple emphysematous bullae with a secundum atrial septal defect
2004, Journal of Cardiothoracic and Vascular AnesthesiaOctreotide-induced hypoxemia and pulmonary hypertension in premature neonates
2003, Journal of Pediatric SurgeryCitation Excerpt :Besides the elevated vascular resistance in these infants, the pulmonary airway resistance also is increased typical of neonates with very low birth weight and respiratory distress.13 So the prolonged and sustained vasoconstrictive effect of octreotide may lead to increased pulmonary vascular pressure and further exacerbate their BPD that would lead to pulmonary hypertension.14 Glasser et al,15 in 1993, reported on a series of 8 patients with persistent hyperinsulinemic hypoglycemia of infancy (included are 2 infants of 33 weeks and 34 weeks gestational age) who received subcutaneous octreotide at a starting dose of 4 to 5 μg/kg/d and maintained up to 10 μg/kg/d for several years.
Address reprint requests to Irwin Gratz, DO, Department of Anesthesiology, Cooper Health System, Robert Wood Johnson Medical School at Camden, Camden, NJ 08103, e-mail: [email protected]