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Biomedical subjects

R D Latimer

Publications and source records attributed to R D Latimer.

At least 19 recordsLinked to original sources
PubMed1997

Effect of aspirin in coronary artery bypass grafting.

OBJECTIVES: To evaluate the effect of aspirin (ASA) therapy on postoperative blood loss, transfusion requirements, reoperation for bleeding, duration of stay in the intensive care unit and in the hospital in a selected population undergoing a first coronary artery bypass grafting (CABG) surgery. DESIGN: Prospective observational study in consecutive patients during a 3-month period. SETTING: A teaching cardiothoracic center. PARTICIPANTS: Two hundred forty consecutive patients undergoing elective coronary artery bypass grafting surgery for the first time. INTERVENTIONS: Two hundred forty consecutive patients admitted for a first CABG the day before surgery were visited. patients with an abnormal routine coagulation screen or taking drugs that might have affected their coagulation mechanisms were prospectively excluded (n = 96). The date of the last dose of ASA was recorded in the 144 remaining patients, and data were acquired prospectively. MEASUREMENTS AND MAIN RESULTS: Total mediastinal blood drainage, blood products usage, reopening, and duration of intensive care unit and hospital stay were recorded. Patients were grouped by days free of ASA. There were no significant differences detected between groups. CONCLUSIONS: In patients undergoing a first CABG and with no known factors affecting their coagulation, ASA therapy did not appear to increase blood loss, reopening for bleeding, or blood products usage requirements during the hospital stay. ASA therapy did not influence the duration of stay in intensive care or in the hospital.

Adult↗
PubMed1996

Extraction of nitric oxide and nitrogen dioxide from an oxygen carrier using molecular sieve 5A.

Nitric oxide (NO) is effective in the management of pulmonary hypertension and shunt-related hypoxia. Nitrogen dioxide (NO2) is formed when the gas is delivered with oxygen. Both oxides of nitrogen have well recognized adverse effects. The scavenging properties of several forms of soda lime have been investigated. A gas flow containing NO 70 ppm and NO2 5 ppm in oxygen was introduced into a vertically mounted Waters' canister containing: (i) 125 g of molecular sieve 5A (a calcium aluminosilicate zeolite) and (ii) 135 g of soda lime containing a potassium permanganate marker. NO and NO2 concentrations were measured at hourly intervals at the entry and exit points using an electrochemical analyser. Extraction ratios (gradient/ inlet x 100) were calculated for a 24-h period. High extraction ratios (in excess of 90%) of NO and NO2 were observed with both compounds for up to 1 h but these declined rapidly after this time with soda lime. In contrast, the molecular sieve produced extraction ratios in excess of 98% for both gases over the 24-h period. We conclude that the molecular seive 5A is a highly effective scavenger of NO and NO2.

Absorption↗
PubMed1995

Treatment of perioperative low cardiac output syndrome.

New approaches to the treatment of perioperative low cardiac output are considered. In particular, use of the phosphodiesterase III inhibitors and their cardiovascular actions are reviewed and contrasted with those of conventional inotropic agents. The increasing recognition of right-sided dysfunction is highlighted, and appropriate therapeutic strategies are considered. The increasing role of pulmonary-specific vasodilators such as inhaled nitric oxide is emphasized. Strategies to preserve right heart perfusion while producing pulmonary vasodilatation are discussed.

Cardiac Output, Low↗
PubMed1995

Somatostatin-induced contraction of human isolated saphenous vein involves sst2 receptor-mediated activation of L-type calcium channels.

A range of somatostatin (SRIF) analogues have been used to characterize the SRIF receptor-mediating contraction of the human saphenous vein. SRIF produced concentration-dependent contractions with an EC50 value of approximately 20 nM. The peptidase inhibitors phosphoramidon and amastatin did not alter the potency of SRIF. The sst2 receptor-selective peptide BIM-23027 was approximately three times more potent than SRIF in contracting the vein, whereas the sst5 receptor-selective peptide L-362855 was approximately 50 times weaker. The sst3 receptor-selective peptide BIM-23056 did not contract the saphenous vein. Contractions to SRIF were not antagonised by the putative SRIF receptor blocker cyclo(7-aminoheptanoyl-Phe-D Trp-Lys-Thr[Bzl]) (CPP), phentolamine, or indomethacin. Decreasing the external calcium concentration reduced the maximum contraction to SRIF in a concentration-dependent manner without altering the EC50 value. Nifedipine and verapamil also markedly reduced the SRIF-induced contraction. SRIF and several SRIF analogues caused contraction of the human saphenous vein by what appeared to be a direct effect on the smooth muscle. Their relative potencies suggest that their effects were mediated by a somatostatin receptor that is like the recombinant sst2 receptor. The receptor transduction mechanism appears to involve activation of L-type calcium channels and entry of extracellular calcium.

Aged↗
PubMed1994

Inhaled nitric oxide in patients with normal and increased pulmonary vascular resistance after cardiac surgery.

We studied the haemodynamic effects of inhaled nitric oxide 40 p.p.m. in two groups of patients after cardiac surgery (mitral valve surgery or coronary artery bypass grafting). Nitric oxide caused a significant reduction in pulmonary vascular resistance after mitral valve surgery in patients who had pre-existing pulmonary hypertension, but no change in haemodynamic state in the coronary artery bypass group of patients, who had normal pulmonary arterial pressures.

Administration, Inhalation↗
PubMed1994

The role of soda lime during administration of inhaled nitric oxide.

We have studied the ability of three commercially available preparations of soda lime to act as nitrogen dioxide scavengers during administration of inhaled nitric oxide. Soda lime, with a green to brown colour change (indicator = potassium permanganate), markedly reduced concentrations of nitrogen dioxide, but also markedly reduced inhaled concentrations of nitric oxide. The other varieties of soda lime, with colour changes from pink to white (indicator = kenazol yellow) or white to violet (indicator = ethyl violet), produced little effect on concentrations of nitrogen dioxide. None of the above soda limes can be recommended for use as a nitrogen dioxide scavenger during administration of inhaled nitric oxide.

Calcium Compounds↗
PubMed1993

Endotoxin-induced organ injury.

OBJECTIVE: To review the effects of endotoxemia on the major organ systems of the body and discuss potential mechanisms of tissue injury. DESIGN: Appraisal of 60 articles representing a cross section of studies relating to in vivo and in vitro responses to endotoxin. MAIN METHODS: Cell cultures, isolated tissue preparations, animal and human studies. RESULTS: Endotoxemia results in the activation of numerous cellular and hematogenous mediators. These mediators range from prostaglandins, thromboxanes, and leukotrienes, to complement components. Tumor necrosis factor may be responsible for initiating many of the observed responses to endotoxin. Species and tissue specificity are a prominent feature of the response to endotoxin. CONCLUSIONS: No single agent can yet be implicated as the common mediator of endotoxin-induced organ injury. Endotoxin initiates the elaboration of a cascade of secondary mediators that amplify the response to the initial insult. The relative importance of individual agents as mediators of the response to endotoxin varies with the experimental model studied.

Animals↗
PubMed1990

Management of donors for heart and heart-lung transplantation.

The quality of donor organs will determine the quality of life for the recipient and the importance of optimal management of the multi-organ donor is that the organs may benefit up to five, critically ill, patients. The basic principle is to maintain sufficient preload to minimise the need for inotropic support and it is recommended that all multiple organ donors should have central venous and arterial pressure monitoring in addition to adequate venous access. The importance of the choice of fluid for volume expansion and the management of the hormonal disturbances which follow brain death are considered.

Brain Death↗
PubMed1990

Management of low cardiac output syndrome after cardiac surgery using enoximone.

This case report describes the use of enoximone, a potent phosphodiesterase F-IV inhibitor with inotropic and vasodilator actions, to treat low output syndrome after cardiac surgery. The reduced cardiac output was unresponsive to a combination of inotropic drugs and intra-aortic balloon counterpulsation was contraindicated. Cardiac output was increased dramatically by enoximone, but systemic vascular resistance and perfusion pressure remained low until the addition of metaraminol.

Aged↗
PubMed1990

Effects of intravenous enoximone following coronary artery bypass surgery.

The effects of intravenous enoximone were investigated in patients with reduced left ventricular ejection fraction following coronary artery bypass graft surgery. Pulmonary capillary wedge pressure was maintained at its original level during therapy. Results showed an improvement in cardiac index of approximately 35% and a reduction of systemic vascular resistance of approximately 30% in 10 out of 16 patients. In an attempt to explain the failure of 6 patients to respond to enoximone therapy, preliminary studies revealed that a repeat dose of enoximone may elicit a response. It is further suggested that postsurgical trauma may change the behaviour of the heart in response to this agent, perhaps due to a reduction in high-energy phosphate levels.

Cardiotonic Agents↗
PubMed1988

Dopexamine hydrochloride, a beta 2 adrenergic and dopaminergic agonist; haemodynamic effects following cardiac surgery.

Twelve patients recovering from open heart surgery received an intravenous infusion of dopexamine hydrochloride, a novel beta 2 adrenergic and dopamine receptor agonist. The mean cardiac index increased from 2.58 to a maximum of 3.64 1 min-1 m-2 (P less than 0.001) and the systemic vascular resistance (SVR) decreased from 1527 to 1116 dyne s cm-5 (P less than 0.001) at a dose of 3 micrograms kg-1 min-1. Heart rate increased with dose from 85 beats min-1 to a maximum of 119 beats min-1 (P less than 0.001). There was no significant change in the pulmonary vascular resistance (PVR) with treatment in the group as a whole. However, PVR decreased (P less than 0.05) in patients who had aortic-valve replacement (AVR) only, whereas in patients who had mitral-valve replacement (MVR) the PVR increased (P less than 0.05). We conclude that dopexamine hydrochloride was well tolerated in patients following cardiac surgery. It produced a significant increase in cardiac output with evidence of afterload reduction and, although the increase in heart rate may limit its use in some patients, dopexamine hydrochloride is potentially of value in the treatment of low cardiac output state following cardiac surgery.

Adrenergic beta-Agonists↗