Anesthetic
Management
of a Hypothyroid
Cardiac
Surgical
Patient
Charles W. Whitten, MD, Terry W. Latson, MD, Kevin W. Klein, MD, Jeff Elmore, MD, Roger Spencer, MD, and Patty Duggar, MD ANY IMPORTANT . lik -L. - in a pZtieiìi
anesthetic
considerations
exist
L..__rL.._.,.:rl:,.- 1 ‘IPI____ IlCbC:__1..2_. mcl”“~;
Wiih ~‘ypuulylululsul.
(1) increased sensitivity to depressant drugs (which may be marked in some patients); (2) a hypodynamic cardiovascular system characterized by decreased heart rate, stroke volume, and cardiac output; (3) decreased oxygen demand; (4) slowed metabolism of drugs, particularly opioids; (5) decreased intravascular fluid volume; (6) impaired ventilatory response to arterial hypoxemia and/or elevation in partial pressure of carbon dioxide; (7) delayed gastric emptying time; (Sj impaired ciearance of free water with resultant hyponatremia; (9) hypothermia; (10) anemia; (11) hypoglycemia; (12) altered neuromuscular excitability, which may interfere with estimation of neuromuscular blockade’; and (13) multiple alterations in the adrenergic nervous system.‘.’ Adrenergic alterations include (1) unresponsive baroreceptor reflexes; (2) primary adrenal insufficiency; (3) decreased sensitivity of p-adrenergic receptors; and (4) decreased number of P-adrenergic receptors. These potential physiological alterations have significant implications regarding patient assessment, use of appropriate invasive monitors in the perioperative period, and selection of both anesthetic and cardioactive drugs. Responses to inotropic drugs may bc influcnced by the accompanying alterations in the adrenergic nervous system. In theory, an inotropic drug that does not denend --r ---- on B-receptor interactions for its effects, would be particularly advantageous in these patients. Amrinone, which exerts its inotropic action via phosphodiesterase (PDE) inhibition, may warrant special consideration in these patients. A case is reported of a patient with coronaq artery disease, aortic stenosis, and concomitant hypothyroidism, who was scheduled to undergo coronary artery bypass grafting (CABG) and aortic valve replacement (AVR). The management of a cardiac surgical patient presenting with hypothyroidism is reviewed. CASE REPORT A ól-year-old white woman with critical aortic stenosis was scheduled for AVR and triple CABG. The patient had a history of angina with minima1 exertion. Past medical history was significant 111, &L..__I> ^Ll^rl__ n ..^^_^ ___..1_.._1.. rpL___ ._.^^ -1 tnyro,o a”lal‘“ll Y yea1s p’evrously. 1 IKLt: was 11” omy I”r history of syncope, congestive heart failure, diabetes mellitus, hypertension, hyperlipidemia, or smoking. In the periadmission period it was felt that the patient had suffered an apical subendocardia1 infarction. At the time of this hospitalization she was taking no medications. Preoperative evaluation showed an ill-appearing
From the Division of CardiovascularlThoracic Anesthesiology, Department of Anesthesiology, University of Texas Southwestem Medical Center, Dallas, TX. Address reprint requests to Charles W. Whitten, MD, Assistant Professor, Associate Directer, Divìsion of CardiovascularlThoracic Anesthesiology, Depatiment of Anesthesiology, 5323 Hany Hines Blvd, Dallas, TX 75235-9068. Copyright 0 1991 by W. B. Saunders Company 1053-077019llO.502-0014$03.00/0
156
white woman in no acute distress whose major complaint was an ..“__..:..._A . ..rl. a ûecnase ,.......,..:,,t, In ..“J_*+ I,...” LI~~I”*llllaLc ,u-I”1L .wGrgl,l ,“I>, aXY”L‘ dLG” .WLLII in appetite. Physical examination was remarkable only for a 216 peak midsystolic murmur at the base of the heart, with radiation to the carotids. NO S, or S, was appreciated. Electrocardiogram (ECG) showed a mild ventricular conduction delay and nonspecific ST-T wave changes in leads V, and V,. Preoperative echocardiography showed normal left ventricular (LV) dimensions and concentric LV hypertrophy, moderate posterior hypokinesis, and a diffusely thickened aortic valve with decreased excursion. One-plus mitral regurgitation and 2+ aortic insufficiency were also noted. Cardiac catheterization showed critical aortic stenosis (valve area = 0.8 cm?) and severe three-vessel coronary artery disease (75% right coronary artery, 90% posterior descending artery, 100% left anterior descending, and 90% left circumflex lesions). Pulmonary artery pressure was 1617 mm Hg and pulmonary capillary wedge pressure was 6 mm Hg. Laboratory studies showed an I.-thyroxine (TJ leve1 of 1.0 &dL (normal, 4.5 to 11.5), a Resin triiodothyronine uptake (T,UR) of 1.0 (normal, 0.X to 1.1), a free thyroid index (T, x T,UR) of 1.O (normal, 4.5 to 11..5), and a thyroid stimulating hormone (TSH) concentration of 36.7 pIU/mL (normal,
Management
of a Hypothyroid
Cardiac
Surgical
Patient
Charles W. Whitten, MD, Terry W. Latson, MD, Kevin W. Klein, MD, Jeff Elmore, MD, Roger Spencer, MD, and Patty Duggar, MD ANY IMPORTANT . lik -L. - in a pZtieiìi
anesthetic
considerations
exist
L..__rL.._.,.:rl:,.- 1 ‘IPI____ IlCbC:__1..2_. mcl”“~;
Wiih ~‘ypuulylululsul.
(1) increased sensitivity to depressant drugs (which may be marked in some patients); (2) a hypodynamic cardiovascular system characterized by decreased heart rate, stroke volume, and cardiac output; (3) decreased oxygen demand; (4) slowed metabolism of drugs, particularly opioids; (5) decreased intravascular fluid volume; (6) impaired ventilatory response to arterial hypoxemia and/or elevation in partial pressure of carbon dioxide; (7) delayed gastric emptying time; (Sj impaired ciearance of free water with resultant hyponatremia; (9) hypothermia; (10) anemia; (11) hypoglycemia; (12) altered neuromuscular excitability, which may interfere with estimation of neuromuscular blockade’; and (13) multiple alterations in the adrenergic nervous system.‘.’ Adrenergic alterations include (1) unresponsive baroreceptor reflexes; (2) primary adrenal insufficiency; (3) decreased sensitivity of p-adrenergic receptors; and (4) decreased number of P-adrenergic receptors. These potential physiological alterations have significant implications regarding patient assessment, use of appropriate invasive monitors in the perioperative period, and selection of both anesthetic and cardioactive drugs. Responses to inotropic drugs may bc influcnced by the accompanying alterations in the adrenergic nervous system. In theory, an inotropic drug that does not denend --r ---- on B-receptor interactions for its effects, would be particularly advantageous in these patients. Amrinone, which exerts its inotropic action via phosphodiesterase (PDE) inhibition, may warrant special consideration in these patients. A case is reported of a patient with coronaq artery disease, aortic stenosis, and concomitant hypothyroidism, who was scheduled to undergo coronary artery bypass grafting (CABG) and aortic valve replacement (AVR). The management of a cardiac surgical patient presenting with hypothyroidism is reviewed. CASE REPORT A ól-year-old white woman with critical aortic stenosis was scheduled for AVR and triple CABG. The patient had a history of angina with minima1 exertion. Past medical history was significant 111, &L..__I> ^Ll^rl__ n ..^^_^ ___..1_.._1.. rpL___ ._.^^ -1 tnyro,o a”lal‘“ll Y yea1s p’evrously. 1 IKLt: was 11” omy I”r history of syncope, congestive heart failure, diabetes mellitus, hypertension, hyperlipidemia, or smoking. In the periadmission period it was felt that the patient had suffered an apical subendocardia1 infarction. At the time of this hospitalization she was taking no medications. Preoperative evaluation showed an ill-appearing
From the Division of CardiovascularlThoracic Anesthesiology, Department of Anesthesiology, University of Texas Southwestem Medical Center, Dallas, TX. Address reprint requests to Charles W. Whitten, MD, Assistant Professor, Associate Directer, Divìsion of CardiovascularlThoracic Anesthesiology, Depatiment of Anesthesiology, 5323 Hany Hines Blvd, Dallas, TX 75235-9068. Copyright 0 1991 by W. B. Saunders Company 1053-077019llO.502-0014$03.00/0
156
white woman in no acute distress whose major complaint was an ..“__..:..._A . ..rl. a ûecnase ,.......,..:,,t, In ..“J_*+ I,...” LI~~I”*llllaLc ,u-I”1L .wGrgl,l ,“I>, aXY”L‘ dLG” .WLLII in appetite. Physical examination was remarkable only for a 216 peak midsystolic murmur at the base of the heart, with radiation to the carotids. NO S, or S, was appreciated. Electrocardiogram (ECG) showed a mild ventricular conduction delay and nonspecific ST-T wave changes in leads V, and V,. Preoperative echocardiography showed normal left ventricular (LV) dimensions and concentric LV hypertrophy, moderate posterior hypokinesis, and a diffusely thickened aortic valve with decreased excursion. One-plus mitral regurgitation and 2+ aortic insufficiency were also noted. Cardiac catheterization showed critical aortic stenosis (valve area = 0.8 cm?) and severe three-vessel coronary artery disease (75% right coronary artery, 90% posterior descending artery, 100% left anterior descending, and 90% left circumflex lesions). Pulmonary artery pressure was 1617 mm Hg and pulmonary capillary wedge pressure was 6 mm Hg. Laboratory studies showed an I.-thyroxine (TJ leve1 of 1.0 &dL (normal, 4.5 to 11.5), a Resin triiodothyronine uptake (T,UR) of 1.0 (normal, 0.X to 1.1), a free thyroid index (T, x T,UR) of 1.O (normal, 4.5 to 11..5), and a thyroid stimulating hormone (TSH) concentration of 36.7 pIU/mL (normal,
