Search PubMed⌕ Search

Biomedical subjects

D L Reich

Publications and source records attributed to D L Reich.

70 records · Page 4Linked to original sources
PubMed1991

Haemodynamic response to induction of anaesthesia with ketamine/midazolam.

The haemodynamic responses following induction of anaesthesia with ketamine and midazolam have not been determined previously. Twenty adult patients for elective myocardial revascularization were randomized to two regimens for induction of anaesthesia. Patients in Group I received ketamine, 2 mg.kg-1, and midazolam, 0.2 mg.kg-1 and those in Group II received ketamine, 2 mg.kg-1, and midazolam, 0.4 mg.kg-1. Measurements were recorded at baseline, 1 min post-induction, and at one, three, five and ten minutes after tracheal intubation. Tachycardia and hypertension (greater than 20% increases from awake baseline values) were treated with esmolol, 250 micrograms.kg-1. There were 11 patients in Group I and nine patients in Group II. There were no significant intergroup differences in demographic or haemodynamic variables. Both groups had decreases (P less than 0.05), in stroke volume, pulmonary capillary wedge pressure, and right ventricular end-diastolic volume at multiple study intervals following anaesthetic induction. None of these changes required clinical intervention. Five patients (all in Group II) had hypertensive responses to tracheal intubation. Preoperative hypertension (mean arterial pressure greater than or equal to 100 mmHg) was a predictor (P less than 0.05) of a hypertensive response to intubation, independent of the midazolam dose. Intravenous ketamine and midazolam was associated with a high incidence (25%) of haemodynamic responses to tracheal intubation. The higher dose of midazolam did not provide any haemodynamic advantage.

Aged↗
PubMed1991

Desmopressin acetate is a mild vasodilator that does not reduce blood loss in uncomplicated cardiac surgical procedures.

Desmopressin acetate (DA) is a synthetic analog of vasopressin that may improve perioperative coagulation in cardiac surgical patients. Twenty-seven adult patients with good left ventricular function and normal preoperative coagulation profiles scheduled to undergo elective cardiac surgery participated in the double-blinded, placebo-controlled study. The 14 patients in the DA group received the drug over 10 minutes (starting 15 minutes after protamine administration). The 13 patients in the placebo group received an equal volume of saline. Preoperative template bleeding time was longer in the placebo group (P = 0.04). Otherwise, there were no statistically significant differences between the groups in demographics, coagulation variables, renal concentrating function, blood loss, or transfusion requirements at any study interval. The only significant hemodynamic differences detected were an increase in cardiac output in the DA group and a corresponding decrease in systemic vascular resistance. Five of 13 patients who received DA required treatment for hypotension, whereas none of 12 patients who received placebo required treatment during the infusion (P = 0.008). The authors conclude that DA causes mild vasodilation, but does not reduce blood loss or transfusion requirements in patients undergoing primary uncomplicated cardiac surgical procedures.

Anesthesia, Intravenous↗
PubMed1990

Nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction in patients with mitral valvular disease.

Using the rapid-response thermistor pulmonary artery catheter and transoesophageal echocardiography, this study examined the effects of 100 per cent oxygen, 70 per cent nitrous oxide/30 per cent oxygen, and 70 per cent nitrogen/30 per cent oxygen on the pulmonary circulation and ventricular function in ten patients with pulmonary hypertension. In comparison with baseline measurements, nitrous oxide administration resulted in small but statistically significant (P less than 0.05) changes in mean arterial pressure (76 +/- 14 to 67 +/- 12), mean pulmonary arterial pressure (37 +/- 14 to 33 +/- 13 mmHg), and cardiac output (3.7 +/- 1.4 to 3.2 +/- 1.1 L.min-1). Seventy per cent nitrogen resulted in no significant changes from baseline. The repeat 100 per cent oxygen measurements were nearly identical to the nitrous oxide measurements. It is concluded that nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction during high-dose fentanyl anaesthesia in patients with mitral valvular disease.

Adult↗
PubMed1990

Importance of atrial systole to ventricular filling predicted by transesophageal echocardiography.

This study documented mitral flow velocity patterns in anesthetized patients with ischemic heart disease and left ventricular dysfunction and investigated the relationship between transmitral flow velocity measurements and the hemodynamic response to ventricular pacing. Twenty-four patients in sinus rhythm without evidence of mitral valve disease undergoing elective myocardial revascularization were studied. Anesthesia consisted of a high-dose opioid-muscle relaxant-oxygen technique. After endotracheal intubation a 3.5-MHz phased-array transesophageal echocardiographic probe was inserted and positioned to obtain a long-axis view of the left atrium and left ventricle. The Doppler sample volume was placed at the mitral annulus with minimal cursor angulation, and the biphasic velocity tracing of transmitral blood flow was recorded. A hemodynamic profile was obtained, and cardiac output was measured in triplicate by thermodilution. Ventricular pacing was then instituted and the hemodynamic and thermodilution measurements were repeated. The peak early filling (E) velocity was 0.34 +/- 0.11 m/s, and the peak atrial (A) velocity was 0.38 +/- 0.09 m/s. The mean E:A ratio was 0.91 +/- 0.3, and the median value was 0.88. In sinus rhythm the cardiac index of those patients with an E:A greater than 0.88 (group 1) was 1.97 +/- 0.32 l/min and those with an E:A less than 0.88 (group 2) was 1.76 +/- 0.50 (NS). During ventricular pacing the patients in group 1 (1.56 +/- 0.32 l/min) had significantly higher cardiac indices than those in group 2 (1.21 +/- 0.31 l/min) (P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The pericardium exerts constraint on the right ventricle during cardiac surgery.

The right ventricle may be particularly susceptible to the effects of pericardial constraint. This study examined the effects of pericardiotomy on right ventricular function. Twenty-four anesthetized patients with coronary artery disease, but without evidence of pericardial pathology, were studied. Anesthesia consisted of fentanyl (100 micrograms.kg-1), diazepam, pancuronium, and 100% oxygen. The American Edwards REF-1 Cardiac Output Computer, rapid-response thermistor pulmonary arterial catheter, and a radial arterial catheter were used to measure hemodynamic variables. Baseline measurements were obtained with the sternum fully retracted. The measurements were then repeated following pericardiotomy by a midline incision. There were significant (P less than 0.05) changes in systolic arterial pressure (+4.5%), mean arterial pressure (+3.7%), systolic pulmonary arterial pressure (+11.8%), cardiac output (+9.1%), stroke volume (+6.9%), right ventricular end-diastolic volume (+7.6%), and right atrial pressure (-8.6%). In the current study, pericardiotomy augmented right ventricular diastolic filling and stroke volume, while the right atrial pressure decreased. These results support the concept of pericardial constraint.

Adult↗
PubMed1989

Ketamine: an update on the first twenty-five years of clinical experience.

In nearly 25 years of clinical experience, the benefits and limitations of ketamine analgesia and anaesthesia have generally been well-defined. The extensive review of White et al. and the cardiovascular review of Reves et al. are broad in their scope and have advanced the understanding of dissociative anaesthesia. Nevertheless, recent research continues to illuminate different aspects of ketamine pharmacology, and suggests new clinical uses for this drug. The identification of the N-methylaspartate receptor gives further support to the concept that ketamine's analgesic and anaesthetic effects are mediated by separate mechanisms. The stereospecific binding of (+)ketamine to opiate receptors in vitro, more rapid emergence from anaesthesia, and the lower incidence of emergence sequelae, make (+)ketamine a promising drug for future research. Clinical applications of ketamine that have emerged recently, and are likely to increase in the future, are the use of oral, rectal, and intranasal preparations for the purposes of analgesia, sedation, and anaesthetic induction. Ketamine is now considered a reasonable option for anaesthetic induction in the hypotensive preterm neonate. The initial experience with epidural and intrathecal ketamine administration has not been very promising but the data are only preliminary in this area. The use of ketamine in military and catastrophic settings is likely to become more common. The clinical availability of midazolam will complement ketamine anaesthesia in several ways. This rapidly metabolized benzodiazepine reduces ketamine's cardiovascular stimulation and emergence phenomena, and does not have active metabolites. It is dispensed in an aqueous medium, which is usually non-irritating on intravenous injection, unlike diazepam. The combination of ketamine and midazolam is expected to achieve high patient acceptance, which never occurred with ketamine as a sole agent. Finally, it is necessary to point out the potential for abuse of ketamine. While ketamine is not a controlled substance (in the United States), the prudent physician should take appropriate precautions against the unauthorized use of this drug.

Administration, Rectal↗
PubMed1989

Effects of doxacurium chloride on biventricular cardiac function in patients with cardiac disease.

The effects of doxacurium chloride, a new long-acting non-depolarizing neuromuscular blocking drug, on cardiac performance were studied in 45 patients undergoing high-dose fentanyl-diazepam-oxygen anaesthesia for cardiac surgery. Data were collected at baseline (10 min after tracheal intubation), and at 2, 5 and 10 min after an i.v. bolus of doxacurium with a rapid-response thermistor pulmonary arterial catheter, using two-dimensional transoesophageal echocardiography, and direct arterial pressure measurement. The patients were allocated to four groups based on the type of surgery and dose of doxacurium (0.05 or 0.08 mg kg-1). No changes in left or right ventricular dimensions or contractility were detected in any group. Although significant changes (P less than 0.05) occurred in several groups, all these changes were clinically insignificant (less than 10% change from baseline values), and were similar to those seen in unstimulated anaesthetized patients. Doxacurium appears to be a safe drug for use in patients undergoing cardiac surgery, and is devoid of significant cardiovascular side effects in the doses tested.

Adolescent↗
PubMed1989

Trendelenburg position and passive leg raising do not significantly improve cardiopulmonary performance in the anesthetized patient with coronary artery disease.

The effects of the Trendelenburg (TREND) position and passive straight leg raising (PLR) on cardiopulmonary performance in 18 anesthetized patients undergoing myocardial revascularization were studied with a two-dimensional transesophageal echocardiography probe and a thermodilution right ventricular ejection fraction (RVEF) pulmonary artery catheter. The TREND position (at 20 degrees) and PLR (at 60 degrees) were studied in relation to the level-supine position in random order. At 3 min, the TREND caused significant (p less than .05) decreases in heart rate (62 +/- 9 to 58 +/- 10 [SD] beat/min) and RVEF (0.48 +/- 0.11 to 0.44 +/- 0.10), and significant increases in mean arterial pressure (77 +/- 11 to 82 +/- 11 mm Hg), mean pulmonary artery pressure (16 +/- 4.3 to 19 +/- 5.5 mm Hg), wedge pressure (11 +/- 4 to 13 +/- 4 mm Hg), cardiac index (CI) (2.36 +/- 0.79 to 2.52 +/- 0.93 L/min.m2), right ventricular end-systolic volume index (44 +/- 21 to 58 +/- 21 ml/m2), right ventricular end-diastolic volume index (83 +/- 24 to 102 +/- 22 ml/m2), and shunt fraction (0.16 +/- 0.06 to 0.19 +/- 0.06). CVP and left ventricular areas did not change significantly. PLR had similar effects as the TREND position, except CI did not change significantly. Thus, the TREND and PLR resulted in minor hemodynamic improvement with right ventricular dilation, decreased RVEF, and impaired oxygenation in the anesthetized cardiac surgical patient.

Anesthesia, General↗
PubMedDate not supplied

Hemostasis in aortic and cardiothoracic surgery.

Hemostasis abnormalities in cardiovascular and aortic surgery remain a major source of morbidity and mortality in patients undergoing such complex procedures. The need for frequent transfusions of red cell and other blood products increases risks and costs to patients and institutions providing patient care. Specifically in cardiovascular and aortic surgery, the nature of the surgery is, at best, semi-elective, and careful preparation to preserve the hemostatic mechanisms of the body is essential. Contact of blood with the extracorporeal circuit induces a hemorrhagic diathesis through a variety of different mechanisms. Dilution of the patient's blood volume by the extracorporeal circuit prime causes depletion of platelets and coagulation factor levels. Aorto intimal disease initiates fibrinolysis by the release of tissue plasminogen activator. Due to the numerous etiologies of bleeding, a combination of blood conservation strategies is suggested. The ideal combination of interventions has yet to be determined and is currently dependent on patient variables, physician and institutional practices, and economic pressures.

Aminocaproic Acid↗