摘要:

Cardiac output (CO) and peripheral resistance (PR), the two major determinants of systemic arterial blood pressure (BP), are regulated principally by the adrenergic (ADR) and renin–angiotensin–aldosterone (RAA) systems. Antihypertensive medications ultimately decrease CO, PR, or both, by acting at various sites in the ADR and RAA pathways or affecting cardiovascular functions directly. Beta–ADR–receptor blockers decrease heart rate (HR) and stroke volume (SV) by preventing the cardiostimulating effects of catecholamines and inhibiting renin release. Alpha–ADR–receptor blockers prevent the vasoconstricting effects of catecholamines and reduce PR (afterload). Angiotensin–converting enzyme inhibitors (ACEI) block the formation of angiotensin, a potent peripheral vasoconstrictor and aldosterone releaser. Hence, ACEI cause a decrease in both PR and CO, the latter by preventing salt and water retention by aldosterone, thereby reducing plasma volume and venous return. Direct vasorelaxation and, thus, a fall in PR can be achieved by vasodilators. These include drugs (e.g. calcium antagonists) that prevent the entry of calcium ions into vascular smooth muscle cells, and others (e.g. nitrovasodilators) that boost the intracellular levels of vasodilating second messengers (e.g. cyclic GMP). Antihypertensives from different classes are often combined to improve the ratio between therapeutic and a

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03818.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The efficacy of flexible fibreoptic bronchoscopy through the laryngeal mask was investigated in 20 patients under total intravenous anaesthesia with propofol, fentanyl, atropine and suxamethonium. Mask size 4 was used for men and size 3 for women. Ventilation was performed with oxygen in air, FIO20.6. The ventilatory pressures were median 18 (9–40) cmH2O (1.8 (0.9–3.9) kPa) before the bronchoscope was inserted. When the tip of the bronchoscope was above the vocal cords the ventilatory pressures increased to 22 (10–43) mmHg (2.2(1.0–4.2) kPa) (P<0.001), and when the tip was situated at the mid‐tracheal level there was a further increase to 24 (12–50) mmHg (2.4(1.2–4.9) kPa) (P<0.001). Maximal gas leakages were median 1 (0–2) 1/min‐1. PEEP at the mid‐tracheal level was 3 (0–7) cmH2O (0.3(0–0.7) kPa). When 15 min of the procedure had elapsed, Pao2was 232 (112–350) mmHg (30.9(14.9–46.6) kPa) and Paco239 (33–46) mmHg (5.2(4.4–6.1) kPa). The lowest oxygen saturation was median 98 (96–100)% and the highest end‐tidal CO234 (24–41) mmHg (4.5(3.2–5.5) kPa). It was easy to examine the laryngeal opening and a good assessment of vocal cord function was allowed when muscle relaxation ceased. We conclude that flexible fibreoptic bronchoscopy through the laryngeal mask is a safe technique provided that total intravenous anaesthesia is used. It is a valuable alternative to flexible bronchos

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03589.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Perioperative hypertension is primarily due to increased systemic vascular resistance (SVR). Therefore, the major therapeutic approaches are directed at reducing vasoconstriction, using drugs that increase cyclic nucleotides or block calcium entry into vascular smooth muscle. Nitroprusside and other nitric oxide–derived vasodilators affect both the resistance vessels and the vascular capacitance bed. Antihypertensive drugs that affect venous return can have unpredictable effects on blood pressure and calculated SVR. The new intravenous dihydropyridine calcium antagonists have arterial vasodilating actions and are especially promising as new therapeutic approaches for perioperative hypertension. Following coronary bypass–grafting, patients have undergone direct mechanical manipulation of their native grafts, coronary arteries, and internal mammary artery, creating a potential risk for coronary or internal mammary spasm. Calcium antagonists may be an important therapy for perioperative hypertension in such patients. Experimental models have demonstrated that calcium antagonists can attenuate the production of inflammatory mediators and thereby reduce cellular damage following reperfusion. These potential anti–inflammatory drugs may prove to offer additional benefits in the therapy of perioperative hypertension. The potential anti–inflammatory and cytoprotective effects of calcium antagonists may make them the ideal agents for the treatment of acute perioperative hyper

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03819.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Changes in arterial oxygen saturation during induction of anaesthesia and intubation were studied using the pulse oximeter. Seventy‐five young ASA I patients undergoing elective uncomplicated surgery were divided equally into three groups. The patients were preoxygenated with 100% oxygen, 50% oxygen: 50% nitrous oxide or 30% oxygen: 70% nitrous oxide for 1 min. All were then induced with thiopentone, paralysed with suxamethonium and orally intubated. Arterial oxygen saturations were continuously recorded by a separate investigator. All groups showed similar arterial desaturation during suxamethonium‐induced apnoea and intubation, but the degree of desaturation was not clinically significant and no patient showed clinical signs of hypoxaemia. Preoxygenation with mixtures of oxygen and nitrous oxide can hasten the build‐up of alveol nitrous oxide concentration and help to smooth induction without compromising oxygenation of pat

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03591.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Shock treatment seems optimal when a “balanced” fluid and volume regimen, including both crystalloid (Ringer's acetate) and about 3% colloid, is used. Dextran is the colloid of choice due to its beneficial effects on plasma volume, hemorrheology, and microvascular blood flow. Dextrans exert, in addition, inhibiting effects on the shock‐ and trauma‐induced activation of the cascade system, whereby the risk of complications in the form of multiple organ failure is reduced. Infusion of red blood cells, plasma or thrombocytes should be based on a proper assessment of each individual patient's actual need of oxygen transporters and coagulation

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb05069.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Isradipine is a new dihydropyridine–derived calcium antagonist. It possesses marked vascular selectivity, resulting in a powerful vasodilating action, whereas, in practical terms, it is devoid of cardiac effects. The usefulness of isradipine in the treatment of arterial hypertension is well documented, both when used as single–drug treatment and in combination with other agents, particularly beta–blockers. Isradipine is well tolerated and does not negatively affect quality of life or capacity for physical exercise. It does not cause metabolic disturbances and, apart from the typical dihydropyridine–type vascular side–effects, specifically, flushing and ankle oedema, there are no specific adverse effects. Even ankle oedema is apparently relatively rare with this compound. Studies in animal models show that isradipine has a potent antiatherosclerotic effect, and a brain tissue–preserving effect after experimental stroke, in doses that are relevant for antihypertensive treatment. If such results can be confirmed in humans, they will undoubtedly be of great clinical

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03820.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03821.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03622.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1991.tb05071.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The significant effects of isradipine in producing arterial vasodilatation and mild negative chronotropic effects without significant negative inotropic effects suggests that this agent should provide excellent antihypertensive efficacy in the treatment of perioperative hypertension. Isradipine may prove to be a safe antihypertensive treatment in patients with impaired ventricular function (cardiac failure), impaired myocardial perfusion (ischaemia), and in cases of selected conduction abnormalities or arrhythmias. The demonstration that its effects are limited to vascular resistance rather than vascular capacitance is an important distinguishing feature of isradipine compared with other antihypertensive agents. Finally, the potential application of this dihydropyridine calcium antagonist for cytoprotection and its effects on atherosclerosis remain exciting therapeutic prospects.

ISSN:0001-5172    

DOI:10.1111/j.1399-6576.1993.tb03822.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY