PubMed Health⌕ Search

Biomedical subjects

C L Lake

Publications and source records attributed to C L Lake.

At least 19 recordsLinked to original sources
PubMed1994

Transoesophageal echocardiography: its role in the operating theatre.

Transoesophageal echocardiography, initially described in 1976, presently includes M-mode, two-dimensional, pulsed wave, continuous wave, and colour flow Doppler imaging techniques. Although transthoracic and epicardial echocardiography may have utility during some surgical procedures, only the transoesophageal approach provides continuous imaging without interruption of surgery in patients ranging in size from 3 kg to adults. Limitations to its uses include the presence of oesophageal disease or abnormal coagulation. The risk of complications in a large series of conscious or anaesthetized patients is small (less than 0.2%). Examples of its perioperative use in detection of air embolism, delineation of aortic pathology, determination of pericardial tamponade, evaluation of septal integrity, and identification of cardiac chamber contents are described. Critical evaluation of its use to evaluate regional and global biventricular function and native/prosthetic valvular function is provided.

Adult↗
PubMed1993

American monitoring: standard and state of the art.

Monitoring of the anesthetized patient, the anesthesia machine, and the patient-machine interface is an essential component of anesthetic practice in order to prevent anesthetic-related injuries resulting from equipment failure or human error. While the optimal monitor to detect anesthetic problems (hypoxia, esophageal intubation, hemodynamic compromise, for example) is unclear at present, American standards require continuous presence of qualified personnel who evaluate patient oxygenation, ventilation, circulation, and temperature. A common monitoring array includes electrocardiogram, autosphygmomanometer, pulse plethysmography/oximetry, stethoscope, anesthetic gas analyzer, thermistor, and nerve stimulator. The role of emerging technologies, including transesophageal echocardiography, automated electrocardiographic analysis of ST segments, transcranial Doppler, and transcranial near infrared spectroscopy are discussed.

Adult↗
PubMed1991

Hemodynamic consequences of desmopressin administration after cardiopulmonary bypass.

Desmopressin acetate is used to reduce blood loss after cardiac surgery. However, there have been reports that hypotension can occur with infusion of desmopressin and that postoperative blood loss is not reduced. In this randomized, double-blinded study, we investigated the effects of desmopressin on hemodynamics, coagulation, and postoperative blood loss in patients undergoing primary elective coronary artery bypass grafting (CABG). After reversal of heparin effect, 20 patients received desmopressin 0.3 micrograms.kg-1, infused over 15 min, and 20 patients received a placebo. Desmopressin produced a small but significant decrease in diastolic blood pressure when compared with the placebo (50.8 mmHg vs. 57.6 mmHg for the desmopressin- and placebo-treated groups, respectively; P = 0.0372). A 20% or greater decrease in mean arterial pressure was observed in 7 of 20 patients receiving desmopressin, whereas only one patient in the placebo-treated group experienced a decrease of this magnitude (P = 0.0177). Reductions in arterial pressure were secondary to decreases in systemic vascular resistance (SVR) (mean SVR before and after the drug infusion, 1,006 and 766 dyn.s.cm-5, respectively, for the desmopressin-treated group; and 994 and 1,104 dyn.s.cm-5, respectively, for the placebo-treated group; P = 0.0078).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Loss, Surgical↗
PubMed1986

Lidocaine enhances intraoperative ventricular defibrillation.

The efficacy of lidocaine during myocardial reperfusion in coronary artery bypass surgery was evaluated in 20 patients randomly assigned to a control group (n = 10) or to receive lidocaine, 1 mg/kg intravenously 5 min before aortic unclamping and cardiac reperfusion, followed by infusion at 40 micrograms X kg-1 X min-1 (n = 10). We recorded ECG leads II and V5 continuously, and number, energy, and current of direct current (DC) shocks starting at 1 joule. The number of low energy DC shocks to sustained defibrillation (5.5 +/- 2.0 vs 3.5 +/- 2.0, mean +/- SD, P less than 0.05) decreased significantly with lidocaine infusion. The energy (11.0 +/- 6.3 vs 5.6 +/- 3.9 joules, P less than 0.05) and current (12.7 +/- 4.2 vs 8.9 +/- 4.7 amperes, not significant) likewise decreased with lidocaine infusion. Energy and current for the first successful shock, although lower in the lidocaine group, were not statistically significantly lower than in the control group. Initial reperfusion rhythm was not influenced by lidocaine. Plasma electrolyte levels, arterial blood gas tensions, myocardial temperature, and surgical technique--factors known to influence defibrillation--were similar in all patients. Administration of lidocaine during myocardial reperfusion allows defibrillation with fewer DC shocks of lower energy and current.

Catecholamines↗
PubMed1985

Influence of magnesium ion on human ventricular defibrillation after aortocoronary bypass surgery.

The administration of magnesium ion (Mg++) has been reported to defibrillate the ventricles and to decrease the incidence of arrhythmias after cardiopulmonary bypass. In a prospective study of 76 randomly selected patients undergoing coronary artery bypass grafting, patients received either no Mg++, 0.25 mEq/kg of Mg++ during cardiopulmonary bypass with the aorta clamped, or 0.375 mEq/kg of Mg++ before cardiopulmonary bypass. Spontaneous resumption of a cardiac rhythm or spontaneous defibrillation during reperfusion was not significantly affected by Mg++ administration. However, the number of shocks to initial and to sustained defibrillation and the energy required for the last direct-current shock was greatest in patients who received Mg++ before bypass and in those whose plasma Mg++ was greater than 2.26 mg/dl. Thus, the administration of Mg++ may have adverse effects on the heart if intraoperative plasma Mg++ exceeds 2.26 mg/dl.

Cardiopulmonary Bypass↗
PubMed1985

Low-energy defibrillation: safe and effective.

During cardiopulmonary bypass, 150 cardiac surgical patients were prospectively evaluated for the number, energy, current, and success rates of direct current (DC) shocks required to terminate reperfusion ventricular fibrillation (1 degree) or ventricular fibrillation occurring subsequent to a nonfibrillatory reperfusion rhythm (2 degrees). Thirty-one percent of 1-J shocks and 58% of 2.5-J shocks defibrillated. Above 2.5 J, the defibrillation success rate reached a plateau of 50-60%. Myocardial resistance decreased significantly after the first shock but remained stable during subsequent shocks. Lower defibrillating currents and myocardial resistances than had been previously reported were observed. The feasibility of low-energy defibrillation during cardiopulmonary bypass was therefore documented.

Cardiopulmonary Bypass↗
PubMed1985

Arch vessel injury during pulmonary artery catheter placement.

We have observed seven instances of unintentional cannulation of major arteries with 8F sheaths during preparation for open-heart operation. When the sheath was removed and the operation delayed, there were no complications; in the two instances in which the open-heart operation was performed immediately after arterial cannulation, there was 1 death due to hemorrhage and 1 false aneurysm of the carotid artery. Elective open-heart operations should be delayed if unintentional cannulation of a major artery occurs.

Cardiac Surgical Procedures↗
PubMed1985

Effects of coronary grafting technique upon reperfusion cardiac rhythm, ventricular function, and other variables.

The effects of different techniques of aortocoronary bypass grafting on reperfusion cardiac rhythm and ventricular function have not been systematically evaluated for possible advantages or disadvantages. The placement of proximal anastomoses before cardiopulmonary bypass and sequential coronary grafting with reperfusion via both the grafts and the native circulation were prospectively compared to traditional grafting and reperfusion via native arteries. More than 40 biochemical, thermal, temporal, hemodynamic, and other variables, including arrhythmias and myocardial failure, were measured intraoperatively and postoperatively. Spontaneous resumption of a cardiac rhythm occurred more frequently with traditional grafting technique in association with a larger cardioplegia volume and a higher serum potassium. However, the disadvantage of the traditional technique was a higher incidence of cardiac failure postoperatively and greater use of isoproterenol after discontinuation of bypass. While cardiac rhythm resumed spontaneously more often with the traditional technique, the increased incidence of cardiac failure postoperatively has serious implications. Thus, placement of proximal anastomoses before cardiopulmonary bypass seems warranted.

Arrhythmias, Cardiac↗