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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The QRS complex in lead V5 was studied during cardiac surgery. R wave amplitude decreased after induction of anesthesia to approximately 50% to 60% of the preanesthetic level before the institution of CPB (P < 0.001). An rS complex appeared immediately after cardioversion and changed in configuration to an Rs complex 15 to 30 minutes after aortic declamping. The R wave continued to recover toward the preanesthetic level at sternal closure. Patients with coronary artery disease had a poorer recovery of the R wave (P < 0.05) than patients with valvular heart disease; the former recovered to only 50% of the preanesthetic level at sternal closure. Nonsurvivors had much smaller R waves (26.1 +/- 20.5%) than survivors (P < 0.001). The R wave peaked 30 to 40 ms after initiation of the QRS complex, which indicates recovery of conductivity and the activation sequence of the left ventricular (LV) free wall, which is easily disturbed by hypothermia, cardioplegia, and ischemia during aortic cross-clamping. Monitoring QRS complex changes in lead V5 appears to be important on weaning from cardiopulmonary bypass to detect regional ischemia, and also to observe electrophysiologic recovery of the LV free wall.
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PMID:QRS complex changes in the V5 ECG lead during cardiac surgery. 147 59

Potassium homeostasis was studied in 30 patients undergoing cardiac surgery by employing cardiopulmonary bypass (CPB) and moderate hypothermia, and using morphine, N2O, relaxant anaesthesia. There was a trend for hypokalemia, and for maintaining a K+ level of 4-4.5 mmol/l, K+ infusion was required during CPB (9.017 mmol/m2 BSA/h). K+ infusion required in the post-operative period was considerably less (1.532 mmol/m2 BSA/h). There was no significant difference in the K+ levels of patients receiving preoperative diuretic therapy, as compared to those not receiving such therapy. Potassium requirement was significantly higher in patients under-going CABG and valvular heart disease, as compared to congenital heart disease. The mean urinary loss of K+ during bypass was found to be 2.95 mmol/m2 BSA/h, which was only 32 per cent of that required to be infused (9.017 mmol/m2 BSA/h). The mean excretion of K+ in the post operative period was significantly higher (4.53 mmol/m2 BSA/h) than K+ required to be infused during this period (1.532 mmol/m2 BSA/h).
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PMID:Potassium homeostasis during & after cardiopulmonary bypass. 207 59

Blood cardioplegia is considered to be superior in oxygenating potential, buffering potential, oncotic, and other physiologic effects. In clinical cases, however, it is unproven whether aerobic metabolism can be obtained by using blood cardioplegia during aortic cross-clamping. Aerobic metabolism during aortic cross-clamping was therefore evaluated in patients with valvular heart disease who underwent relatively long periods of ischemic arrest. Myocardial metabolism of oxygen, lactate and pyruvate was studied in 14 patients under 126 +/- 41.2 min of cardiac arrest, and intramyocardial carbon dioxide tension (PmCO2) was also monitored continuously in 23 patients who received 121 +/- 29.8 min of aortic cross-clamping. After aortic cross-clamping, 4 degrees C St. Thomas solution was infused for immediate cooling, followed by blood cardioplegia for replenishment every 20-25 min. Blood cardioplegia and myocardial temperature were maintained within 15-20 degrees C by using an automatic cardiac hypothermia control system. Myocardial oxygen extraction during the pre-ischemic period was 26.8 +/- 13.3%. At 15 and 30 min after reperfusion, it was 30.0 +/- 10.8% and 33.8 +/- 8.2%, respectively. During ischemic arrest, myocardial oxygen extraction decreased, but the infusion of blood cardioplegia kept it above 14.0 +/- 9.3% at all times. As for lactate metabolism, although some cases showed lactate production even before the aortic cross-clamping, lactate extraction was attained in some cases during blood cardioplegia perfusion. Changes in excess lactate and redox potential of lactate and pyruvate (delta Eh) showed that aerobic metabolism could be obtained in 13/32 (41%) infusions of blood cardioplegia. PmCO2 at the aortic cross-clamp was 47.0 +/- 27.7 mmHg, and gradually rose during the ischemic arrest, but only as far as 68.4 +/- 64.8 mmHg at the time of cross-clamp release. PmCO2 decreased with each infusion of blood cardioplegia, and the decrease lasted up to 10 minutes. Though PmCO2 began to rise thereafter, the effect of blood cardioplegia continued as long as 20-25 min after the infusion. In conclusion, blood cardioplegia provides aerobic metabolism during aortic cross-clamping even in clinical setting, provided that cardiac hypothermia and delivery of cardioplegic solution are maintained appropriately.
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PMID:[Clinical study of blood cardioplegia--for aerobic metabolism during aortic cross-clamping]. 276 7

In the period between the opening of our heart center in November 1984 and May 1986, 2001 cardiac operations were performed with the aid of cardiopulmonary bypass. Almost three quarters (73.5%, n = 1471) of the patients had coronary artery disease and 20% (n = 359) had acquired valvular heart disease. In 47 of 1471 patients who underwent coronary artery bypass grafting, a simultaneous carotid endarterectomy was performed. They included 36 men and 11 women, aged between 51 and 78 years (mean 64 years). Preoperatively, 12 patients had cerebrovascular symptoms and 35 were neurologically asymptomatic. Twenty-three had unilateral carotid stenosis and 24 had bilateral or multiple vessel disease of the extracranial arteries. All except four patients had triple-vessel coronary artery disease. In three patients with aortic valve disease, coronary bypass, carotid endarterectomy, and aortic valve replacement were performed simultaneously. Cardiopulmonary bypass was instituted before carotid endarterectomy was performed, with mild hypothermia and hemodilution for added protection. Electroencephalographic monitoring was used throughout the operation. Forty-six of the 47 patients survived the operation without neurologic or cardiac complications. One patient had a neurologic deficit with hemiplegia and coma, which was lethal. We conclude that simultaneous endarterectomy of significant extracranial artery stenosis in candidates for coronary bypass is a method safe enough to justify its routine use.
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PMID:Operative strategy in combined coronary and carotid artery disease. 333 97

The interrelation between the energy and nitrogenous metabolism of the myocardium during cardioplegia has been studied in patients with congenital valvular heart disease (tetralogy of Fallot--12 patients, ventricular septal defect--5 patients). Whole body hypothermia with repeated heart reperfusion with cold cardioplegic blood perfusate was used for the protection of the myocardium. However, ATP level of the myocardium of some patients decreased by 20% and more of the baseline. This loss was accompanied by a reduction in glutamate and aspartate levels and a rise in ammonium and alanine levels in the myocardium (by 17.7 +/- 3.8; 17.6 +/- 5.9; 61.4 +/- 12.5 and 92.4 +/- 26.3% of the baseline, respectively).
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PMID:[Effect of cardioplegia on nitrogen and energy metabolism of the human heart]. 366 4

Intramyocardial pH and temperature data recorded in 100 patients undergoing cardiac operations were analyzed to elucidate the effects of ventricular fibrillation and reflow. All patients underwent a single period of aortic clamping. Systemic hypothermia (25 degrees C) and intermittent cold crystalloid K+ cardioplegia were employed for myocardial protection. Baseline myocardial pH was 6.88 +/- 0.03 at a temperature of 36.5 degrees +/- 0.2 degree C. During the period of hypothermic ventricular fibrillation prior to aortic clamping, ventricular fibrillation did not affect myocardial pH in 45 patients (Group 1). In 21 patients (Group 2), it caused a significant drop in intramyocardial pH despite cooling. Group 2 patients had a higher incidence of valvular heart disease and left ventricular hypertrophy. They also exhibited low intramyocardial pH values during the subsequent periods of aortic clamping and reflow, indicating inadequate myocardial protection. During the period of reflow, reperfusion acidosis (pH less than 6.8 at 32 degrees C) was encountered in 39 patients (Group B) as opposed to 37 patients (Group A) whose pH remained well above 6.8 during that period. Group B patients had a higher incidence of valvular heart disease and left ventricular hypertrophy, tended to have more ischemic anterior walls prior to cardiopulmonary bypass, sustained longer periods of aortic clamping, had intramyocardial pH evidence of suboptimal protection during aortic clamping, were affected more adversely by ventricular fibrillation during reflow, and tended to have a higher operative mortality. Thus: Depending on the underlying myocardial disease, the adequacy of protection during aortic clamping, and the conditions of reflow, intramyocardial pH in man can fall significantly during ventricular fibrillation and reflow. The metabolic correlate of injury with reflow is a reperfusion acidosis that can reach as low as pH 5.98. When encountered, reperfusion acidosis can be minimized by prompt defibrillation.
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PMID:Observations on 100 patients with continuous intraoperative monitoring of intramyocardial pH. The adverse effects of ventricular fibrillation and reperfusion. 396 2

Between November, 1964 and January, 1983, 70 consecutive patients underwent primary repair of complex valvular heart disease, defined as repair or replacement of two or more cardiac values alone or with other concomitant cardiac procedures. A total of 163 operative procedures were performed on the 70 patients for an average of 2.33 procedures per patient. Review of these cases allowed the patients to be divided into two distinct groups, those receiving systemic hypothermia and cold potassium cardioplegic arrest of the heart (C) and those having other myocardial preservation techniques (NC). Thirty-three patients received C and are compared with 37 patients who received NC. The two patient groups were comparable when considered for preoperative cardiac index and functional classification though patients in C group were older. In the C group, 10 of 32 patients (31%) had associated coronary artery bypass grafting in contrast to 2 of 37 patients (5.4%) in the NC era. The mortality of the C group was 2 of 33 (6%) vs 14 of 37 (37.8%) in the NC group (P less than .001). Of the 14 deaths in the NC patients, 10 were due to low cardiac output syndrome. While other factors have undoubtedly played a role, improved myocardial preservation by the use of C and attention to coronary artery pathology may have contributed to the improved operative mortality in this group of patients with complex valvular heart disease.
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PMID:The effect of myocardial preservation technique on operative mortality in complex valvular heart disease. 399 62

Recent studies suggest that plasma levels of alpha-hANP may reflect the severity of heart failure, but mechanism whereby ANP secretion increase is not known. Changes in alpha-hANP concentration in the arterial (A-ANP) and coronary sinus blood (CS-ANP) during and after the cardiopulmonary bypass (CPB) were measured to investigate the role of ANP in patients undergoing cardiac surgery. Fifteen patients were divided into 2 group; Group I, valvular heart disease (n = 9), Group II, coronary artery disease (n = 6). Both A-ANP and CS-ANP were significantly higher in the Group I than Group II before and during CPB. The difference between two groups decreased and was insignificant after CPB. The CS-ANP was twice as high as A-ANP at simultaneous sampling point. Significant correlations between the changes in PCWP (delta PCWP) and delta A-ANP (p < 0.01), delta RAP and delta A-ANP (p < 0.02) and an inverse linear correlation between CI and A-ANP (p < 0.01) were observed. Not a significant correlation was found between ANP and urine volume, urinary sodium excretion and other renal functional parameters during and after CPB. Hypothermia and the use of mannitol in large quantities were considered to be factors. In the Group I, A-ANPs were also measured in the postoperative follow-up period. A-ANP remained elevated above 100 pg/ml in patients with poor and decreased below 100 pg/ml with good prognostic signs 3 to 6 months postoperatively. From these results, it is suggested that alpha hANP is secreted from the atrial wall to the coronary sinus vein and the levels of alpha-hANP in the perioperative and follow-up period after heart surgery, especially in the valvular heart disease, are considered to reflect the cardiac performance.
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PMID:[Changes of alpha hANP concentration in arterial and coronary sinus blood during and after cardiopulmonary bypass]. 851 51

Arrhythmia is the most common perioperative cardiac complication during noncardiac surgery. Most perioperative arrhythmia is benign, but fatal arrhythmia can occur, requiring emergency care. Arrhythmia is divided into tachycardia and bradycardia. Both arrhythmias often result in cardiac failure. Ischemic heart disease often causes premature ventricular contraction or ventricular tachycardia. Hypertensive heart disease or valvular heart disease can lead to atrial fibrillation or supraventricular tachycardia. Although patients may not have cardiac disease, hypoxia, hypovolemia, electrolyte disturbance, acidosis, and hypothermia can also cause arrhythmia. Patients with pacemakers or implantable cardiodefibrillators (ICDs) are affected by electric cauterization, which interferes with the sensing and inhibits the pacing of pacemakers as well as ICDs If this occurs, the mode of pacemakers and ICDs must be reset during surgery.
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PMID:[Non-cardiac surgery for patients with arrhythmia]. 1593 53

We reviewed our experience of intraoperative type A aortic dissection during cardiovascular surgery. From January 1998 to May 2009, intraoperative aortic dissection occurred in 10 of 3421 cardiac surgical patients (M:F=4:6, 62.4+/-8.0 years). Preoperative diagnoses were valvular heart disease (n=6), ischemic heart disease (n=2), combined disease (n=1) and aortic aneurysm (n=1). All underwent total circulatory arrest (TCA) with retrograde cerebral perfusion and the torn aorta was replaced (n=8) or repaired (n=2). Iatrogenic type A dissection occurred in 0.29% of patients. It was related with cannulation of ascending aorta (n=4), axillary artery (n=2), aortic root (n=2), and femoral artery (n=1) and aortotomy repair (n=1). Mortality rate was 40% (4/10). After adoption of routine intraoperative transesophageal echocardiography, mortality rate decreased from 75% (3/4) to 17% (1/6) (P=0.190). We initiated TCA before achieving deep hypothermia in three of four non-survivors. There was a trend of increased mortality when the disease extended beyond aortic arch (67%, 4/6 vs. 0%, 0/4; P=0.076). Although intraoperative aortic dissection occurred in <0.3% of our patient population, mortality was high, especially when it extended beyond the arch vessels. Better results were expected when early recognition and proper treatment under deep hypothermic circulatory arrest could be performed.
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PMID:Iatrogenic type A aortic dissection during cardiac surgery. 2029 47


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