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Preoperative glucose-insulin-K+ therapy for cardiac protection: What can be recommended?
CORRESPONDENCE
Total Anomalous Pulmonary Venous Connection To the Editor: I am writing to comment on the excellent article by Drs Adnan Cobanoglu and Victor D. Menashe entitled "Total anomalous pulmonary venous connection in neonates and young infants: repair in the current era" [l]. This fine review article points out the improved success in the management of patients with total anomalous pulmonary venous connection. I want to emphasize the important points of surgical technique in the repair of these anomalies. Because of embryologic variations, the tissue volume of the left atrium of these patients is reduced by the volume of anomalous vein diverted elsewhere (ascending or descending vein). Therefore, our technique has been to use the ascending and descending veins as part of the repair: During bypass cooling before circulatory arrest, the confluence and ascending or descending veins are extensively mobilized. These veins are then ligated and transected and the incision in the ascending and descending vein is taken widely into the confluence. Hence, we are left with a Y-shaped vein. Depending on whether it is an ascending or descending vein, this large, Y-shaped vein is anastomosed to the left atrium and often carried obliquely to the tip of the left atrial appendage. The anastomosis is fashioned so that the long limb of the Y is rotated in the appropriate fashion, making the total diameter of the anastomosis larger than the mitral valve orifice. This simplified surgical repair allows direct suture closure of the atrial septa1 defect and essentially doubles the left atrial side. Late follow-up has demonstrated normal size and growth of the left atrium [2].
index was even slightly better in a subgroup of patients in whom initial cardiac index was less than 2.5 L . min . m '. Our major concern with the GIK infusion protocol proposed in this study is the risk of delayed hypoglycemia from the high insulin doses. In fact, Girard and co-workers note in the Comment section of the article that hypoglycemia did occur and that the risk was greatest at 3 hours postoperatively. However, examination of the serum glucose data at that period shows no significant difference between the groups: 12.2 2 2.8 mmol/L with GIK therapy and 13.3 ? 3.8 mmol/L for the controls. Thus, we have no insight into, or evidence of, the extent of the risk of hypoglycemia caused by the protocol, as outlined; there is only a statement by Girard and co-workers that there is no longer a risk of hypoglycemia with their present practice of administering glucose postoperatively at 15 g/h for 8 hours. Therefore, what protocol of GIK therapy can be supported at this time? If GIK therapy is contemplated, the recommendation of Wiese and Askanazi [3] for use of a modest glucose concentration administered over many hours preoperatively appears to have merit. They particularly note the protocol studied by Oldfield and colleagues (41, which involved administration of 1,000 mL of 20% glucose containing 10 units of soluble insulin, 45 mmol of KCI, and 2000 units of heparin over a 12-hour period before the operation; this procedure was associated with a 56% increase in cardiac glycogen content (p < 0.001) and fewer hemodynamic complications and dysrhythmias 141.
Vajubhai T. Sanchala, M D Mario A. lnchiosa, jr, PhD Departments of Anesthesiology and Pharniacology
Steven 1. Phillips, M D
New York Medical College
The Heart Center 41 1 Laurel, Suite 3250 Des Moines, ZA 50314
References
References 1. Cobanoglu A, Menashe VD. ,Total anomalous pulmonary venous connection in neonates and young infants: repair in the current era. Ann Thorac Surg 1993;55:4>9. 2. Phillips SJ, Kongtahworn C, Zeff RH, Skinner JR, Chandramouli B, Gay JH. Correction of total anomalous pulmonary venous connection below the diaphragm. Ann Thorac Surg 1990;49:7349.
Preoperative Glucose-Insulin-K+ Therapy for Cardiac Protection: What Can Be Recommended? To the Editor: Glucose-in~u1in-K~ (GIK) therapy is widely used for its potential benefits during hypoxic cardioplegia associated with cardiac operations. Girard and co-workers [ l ] recently reported in The Annals the results of their investigations on the value of a 1-hour infusion of large doses of glucose (0.5 g kg * h- I ) and insulin (1.0 U kg I * h I ) immediately before cardiopulmonary bypass. Girard and co-workers note that the high doses and high insulin/ glucose ratio chosen for this study were patterned after the study of Haider and associates [2]. Both the earlier [Z] and recent study [I] suggest that the cardioprotective effects anticipated or observed with these high doses may be due to increased synthesis or preservation of cardiac glycogen; cardiac glycogen levels were not measured in either study, however. Girard and co-workers [l] demonstrated significantly improved cardiac index and decreased systemic vascular resistance at certain periods after cardiopulmonary bypass; the percent improvement in cardiac
0 1993 by The Society of Thoracic Surgeons
Valhalla. NY
10595
1. Girard C, Quentin P, Bouvier H, et al. Glucose and insulin supply before cardiopulmonary bypass in cardiac surgery: a double-blind study. Ann Thorac Surg 1992;54:25943. 2. Haider W, Benzer H, Schutz W, Wolner E. Improvement of cardiac preservation by preoperative high insulin supply. J Thorac Cardiovasc Surg 1984;88:294-300. 3. Wiese S, Askanazi J. Glucose/insulin/potassium therapy: a reevaluation of myocardial benefits during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 1992;6:517-20. 4. Oldfield GS, Commerford PJ, Opie LH. Effects of preoperative glucose-insulin-potassium on myocardial glycogen levels and on complications of mitral valve replacement. J Thorac Cardiovasc Surg 1986;91:87&8.
How to Prevent Pleural Opening in Harvesting the Internal Mammary Arteries To the Editor: In dissecting the internal mammary artery (IMA) for coronary artery bypass grafting, the pleura may be kept intact when possible, or it may be opened intentionally [I]. Pleural opening, however, is apparently disadvantageous because of the unnoticed pooling of circulatory blood in the pleural cavity during cardiopulmonary bypass, the requirement of airtight chest tubes, and possible injury of the lung during redo operation. Kecently, Noera and colleagues [2] reported that postoperative complications including bleeding, surgical reexploration, pleural effusion, hemidiaphragm impairment, pericarditis, sternal infection, chest pain, and respiratory insufficiency in the group without pleurotomy were significantly less than those in the group with pleurotomy. Because of the relatively high frequency of pleural Ann Thorac Surg 1993;56:395402
*
0003-4975/93/$6.00
Total Anomalous Pulmonary Venous Connection To the Editor: I am writing to comment on the excellent article by Drs Adnan Cobanoglu and Victor D. Menashe entitled "Total anomalous pulmonary venous connection in neonates and young infants: repair in the current era" [l]. This fine review article points out the improved success in the management of patients with total anomalous pulmonary venous connection. I want to emphasize the important points of surgical technique in the repair of these anomalies. Because of embryologic variations, the tissue volume of the left atrium of these patients is reduced by the volume of anomalous vein diverted elsewhere (ascending or descending vein). Therefore, our technique has been to use the ascending and descending veins as part of the repair: During bypass cooling before circulatory arrest, the confluence and ascending or descending veins are extensively mobilized. These veins are then ligated and transected and the incision in the ascending and descending vein is taken widely into the confluence. Hence, we are left with a Y-shaped vein. Depending on whether it is an ascending or descending vein, this large, Y-shaped vein is anastomosed to the left atrium and often carried obliquely to the tip of the left atrial appendage. The anastomosis is fashioned so that the long limb of the Y is rotated in the appropriate fashion, making the total diameter of the anastomosis larger than the mitral valve orifice. This simplified surgical repair allows direct suture closure of the atrial septa1 defect and essentially doubles the left atrial side. Late follow-up has demonstrated normal size and growth of the left atrium [2].
index was even slightly better in a subgroup of patients in whom initial cardiac index was less than 2.5 L . min . m '. Our major concern with the GIK infusion protocol proposed in this study is the risk of delayed hypoglycemia from the high insulin doses. In fact, Girard and co-workers note in the Comment section of the article that hypoglycemia did occur and that the risk was greatest at 3 hours postoperatively. However, examination of the serum glucose data at that period shows no significant difference between the groups: 12.2 2 2.8 mmol/L with GIK therapy and 13.3 ? 3.8 mmol/L for the controls. Thus, we have no insight into, or evidence of, the extent of the risk of hypoglycemia caused by the protocol, as outlined; there is only a statement by Girard and co-workers that there is no longer a risk of hypoglycemia with their present practice of administering glucose postoperatively at 15 g/h for 8 hours. Therefore, what protocol of GIK therapy can be supported at this time? If GIK therapy is contemplated, the recommendation of Wiese and Askanazi [3] for use of a modest glucose concentration administered over many hours preoperatively appears to have merit. They particularly note the protocol studied by Oldfield and colleagues (41, which involved administration of 1,000 mL of 20% glucose containing 10 units of soluble insulin, 45 mmol of KCI, and 2000 units of heparin over a 12-hour period before the operation; this procedure was associated with a 56% increase in cardiac glycogen content (p < 0.001) and fewer hemodynamic complications and dysrhythmias 141.
Vajubhai T. Sanchala, M D Mario A. lnchiosa, jr, PhD Departments of Anesthesiology and Pharniacology
Steven 1. Phillips, M D
New York Medical College
The Heart Center 41 1 Laurel, Suite 3250 Des Moines, ZA 50314
References
References 1. Cobanoglu A, Menashe VD. ,Total anomalous pulmonary venous connection in neonates and young infants: repair in the current era. Ann Thorac Surg 1993;55:4>9. 2. Phillips SJ, Kongtahworn C, Zeff RH, Skinner JR, Chandramouli B, Gay JH. Correction of total anomalous pulmonary venous connection below the diaphragm. Ann Thorac Surg 1990;49:7349.
Preoperative Glucose-Insulin-K+ Therapy for Cardiac Protection: What Can Be Recommended? To the Editor: Glucose-in~u1in-K~ (GIK) therapy is widely used for its potential benefits during hypoxic cardioplegia associated with cardiac operations. Girard and co-workers [ l ] recently reported in The Annals the results of their investigations on the value of a 1-hour infusion of large doses of glucose (0.5 g kg * h- I ) and insulin (1.0 U kg I * h I ) immediately before cardiopulmonary bypass. Girard and co-workers note that the high doses and high insulin/ glucose ratio chosen for this study were patterned after the study of Haider and associates [2]. Both the earlier [Z] and recent study [I] suggest that the cardioprotective effects anticipated or observed with these high doses may be due to increased synthesis or preservation of cardiac glycogen; cardiac glycogen levels were not measured in either study, however. Girard and co-workers [l] demonstrated significantly improved cardiac index and decreased systemic vascular resistance at certain periods after cardiopulmonary bypass; the percent improvement in cardiac
0 1993 by The Society of Thoracic Surgeons
Valhalla. NY
10595
1. Girard C, Quentin P, Bouvier H, et al. Glucose and insulin supply before cardiopulmonary bypass in cardiac surgery: a double-blind study. Ann Thorac Surg 1992;54:25943. 2. Haider W, Benzer H, Schutz W, Wolner E. Improvement of cardiac preservation by preoperative high insulin supply. J Thorac Cardiovasc Surg 1984;88:294-300. 3. Wiese S, Askanazi J. Glucose/insulin/potassium therapy: a reevaluation of myocardial benefits during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 1992;6:517-20. 4. Oldfield GS, Commerford PJ, Opie LH. Effects of preoperative glucose-insulin-potassium on myocardial glycogen levels and on complications of mitral valve replacement. J Thorac Cardiovasc Surg 1986;91:87&8.
How to Prevent Pleural Opening in Harvesting the Internal Mammary Arteries To the Editor: In dissecting the internal mammary artery (IMA) for coronary artery bypass grafting, the pleura may be kept intact when possible, or it may be opened intentionally [I]. Pleural opening, however, is apparently disadvantageous because of the unnoticed pooling of circulatory blood in the pleural cavity during cardiopulmonary bypass, the requirement of airtight chest tubes, and possible injury of the lung during redo operation. Kecently, Noera and colleagues [2] reported that postoperative complications including bleeding, surgical reexploration, pleural effusion, hemidiaphragm impairment, pericarditis, sternal infection, chest pain, and respiratory insufficiency in the group without pleurotomy were significantly less than those in the group with pleurotomy. Because of the relatively high frequency of pleural Ann Thorac Surg 1993;56:395402
*
0003-4975/93/$6.00