Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The management of increased intracranial pressure (ICP) in patients with an associated acute lung injury is difficult. High levels of PaCO2 as tolerated for permissive hypercapnia are deleterious for cerebral circulation. In such circumstances, tracheal gas insufflation (TGI), which was recently proposed to reduce PaCO2, may be of benefit. We report the cases of two patients with severe adult respiratory distress syndrome and head trauma complicated with elevated ICP. The introduction of TGI decreased PaCO2 by 17 and 26%, decreased ICP, and increased calculated cerebral perfusion pressure. We conclude that TGI could be added to a pressure-targeted strategy of ventilatory management when severe adult respiratory distress syndrome was associated to an intracranial hypertension.
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PMID:Intracranial hypertension and adult respiratory distress syndrome: usefulness of tracheal gas insufflation. 747 82

Controversy has been raised about the effects of systemic carbon dioxide accumulation versus the intra-abdominal pressure on hemodynamics during laparoscopy. We compared the acid-base and hemodynamic changes during pneumoperitoneum in a randomized cross-over study between CO2 and nitrogen gases to test the hypothesis that the CO2 absorbed during laparoscopy, rather than the 15 mmHg intra-abdominal pressure created, accounted for these changes. Eight adult pigs were anesthetized and ventilated with a fixed minute ventilation. Metabolic function was measured from analysis of expired flow by a metabolic measurement cart. After baseline periods, animals were randomized into two groups, for 2 hr of either CO2 or nitrogen pneumoperitoneum at 15 mmHg intra-abdominal pressure, followed by 1 hr of recovery. After at least a 48-hr recovery period, the experiment was repeated with the other gas. Metabolic data revealed that there was a significant absorption of CO2 gas across the peritoneal epithelium during CO2 pneumoperitoneum. Animals insufflated with CO2 gas experienced a 75% increase in pulmonary CO2 excretion, with significant acidemia and hypercapnia, whereas there were no acid-base disturbances in those with nitrogen insufflation. Oxygen consumption remained essentially unchanged in both groups, even during pneumoperitoneum. CO2 pneumoperitoneum was also associated with systemic and pulmonary arterial hypertension and a reduction in stroke volume of up to 15%. Pneumoperitoneum alone did not compromise hemodynamics. Pneumoperitoneum using CO2 gas during laparoscopy resulted in systemic CO2 absorption across the peritoneum. This led to acidemia, hypercapnea, and depressed hemodynamics. The intra-abdominal pressure routinely used during laparoscopic surgery did not affect metabolic function, acid-base balance, or hemodynamics in the experimental model.
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PMID:Effector of hemodynamics during laparoscopy: CO2 absorption or intra-abdominal pressure? 756 24

Among the techniques of cerebral protection, the use of controlled arterial hypertension is based on the following arguments: 1) Cerebral ischaemia is the final common pathway of any insult to the brain, particularly through secondary lesions. Causes of secondary cerebral lesions include pressure under the brain retractors, temporary clipping, arterial hypotension, hypoxaemia, anaemia and hypercapnia. 2) In the brain, the critical lower value for cerebral blood flow is around 25 mL.100g-1.min-1, under which two types of ischaemic areas can be defined: the penlucida type where cerebral function is abolished, without permanent cerebral lesion and the penumbra type where cerebral tissue recovers only if flow is rapidly restored. In the latter case the duration of ischaemia is very important. 3) Cerebral blood flow is maintained stable within a large range of variations of mean arterial pressure through the autoregulation mechanisms, which is based on vasomotricity of the cerebral circulation, which implies major variations in cerebral blood volume. However, autoregulation needs several dozens of seconds to be achieved. Therefore, sudden variations in mean arterial pressure are associated with short lasting but major variations in cerebral blood volume. 4) In case of increased intracranial pressure, a decrease in cerebral perfusion pressure causes cerebral vasodilation through the autoregulation mechanism, with an increase in cerebral blood volume which will, in turn, increase intracranial pressure and thus decrease cerebral perfusion pressure, and so on. This is the vasodilatory cascade. The therapeutical increase in mean arterial pressure will correct this phenomenon and decrease intracranial pressure. This is called the vasoconstrictive cascade.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Controlled hypertension and cerebral protection]. 767 93

We measured regional cerebral blood flow (rCBF) in young and old Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats by a minimally invasive microsphere technique. Blood flows to the cerebrum, diencephalon, mesencephalon, cerebellum and pons-medulla during normocapnia were determined. To test the ability of the vessels to dilate, rCBF was also measured during hypercapnia. Reactivity to CO2 was calculated as delta rCBF/delta paCO2. In the old SHR, blood flow to the pons-medulla (88 +/- 8 ml/min/100 g, mean +/- SEM) was markedly lower than that in the young SHR (107 +/- 4 ml/min/100 g, p < 0.05), whereas the difference of those values in the old and young WKY rats was slight (0.05 < p < 0.1). There were no differences in the values of blood flow to the cerebrum, diencephalon, mesencephalon or cerebellum between the young and old rats in both species. Cerebrovascular CO2 reactivity was markedly impaired in the old SHR (p < 0.05) compared to that in the young SHR, but the difference in reactivity in the WKY rats was not significant. The results indicate that blood flow to the pons-medulla is reduced in association with age, particularly in the hypertensive animals, and that the ability of the cerebral vessels to dilate is impaired homogeneously by the combination of chronic hypertension and aging.
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PMID:Effects of aging and chronic hypertension on cerebral blood flow and cerebrovascular CO2 reactivity in the rat. 773 29

This randomized double-blind study compared the hemodynamic and metabolic effects of pancuronium and vecuronium during treatment of shivering after cardiac surgery with hypothermic cardiopulmonary bypass. Thirty sedated and pain-free patients who shivered after cardiac surgery were treated with pancuronium (n = 15) or vecuronium (n = 15) 0.08 mg/kg. Baseline values of heart rate (HR), mean arterial pressure, arterial and venous blood gases, total body oxygen consumption indexed to body surface area (VO2-I), and pressure work index (PWI, an estimate of myocardial oxygen consumption) were measured on arrival in the intensive care unit, at onset of shivering, and repeatedly for 2 h after treatment. Continuous ST segment analysis of leads II and V5 were used for detection of myocardial ischemia. Treatment of shivering with pancuronium decreased VO2-I by 32% (P = 0.0001). This was accompanied by a 14% increase in HR (P = 0.001) and a 10% increase in PWI (P = 0.03). Vecuronium decreased VO2-I by 36% (P = 0.003) with a 4% decrease in HR (P = 0.04) and a 6% decrease in PWI (P = 0.06). Myocardial ischemia (n = 3) and ventricular arrhythmias (n = 3) occurred in five patients treated with pancuronium. Only one patient treated with vecuronium had ventricular arrhythmia (P = 0.08). Seven patients treated with pancuronium and eight treated with vecuronium were taking beta-adrenergic blockers preoperatively which was associated with lower HR (96 +/- 16 vs 109 +/- 15 bpm; P = 0.025) and lower PWI (8.8 +/- 1.2 vs 10.7 +/- 1.92 mL.min-1 x 100 g-1; P = 0.003) at onset of shivering. However, beta-adrenergic blockers did not attenuate the relative HR increase induced by pancuronium. No relationship was found between hypercapnia and tachycardia or hypertension. These results suggest that, when compared to pancuronium for treatment of postoperative shivering, vecuronium may be advantageous because it does not increase myocardial work. The disproportionate relationship between VO2-I and PWI after treatment with muscle relaxants indicates that increased VO2-I does not contribute significantly to the hemodynamic disturbances associated with shivering. These disturbances are more likely the results of increased adrenergic activity related to pain and recovery from anesthesia. Shivering and its associated hemodynamic disturbances appear to be concomitant but independent signs of awakening.
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PMID:Pancuronium or vecuronium for treatment of shivering after cardiac surgery. 791 90

Fenoldopam (FE), a dopamine DA1-receptor agonist, has been introduced for treatment of arterial hypertension and heart failure and for preservation of renal function. Vasodilators are generally assumed to affect all vascular beds including the cerebral circulation. We have evaluated effects of FE-induced (4 micrograms.kg-1.min-1) arterial hypotension on intracranial pressure (ICP) and intraocular pressure (IOP) under conditions of normal and increased intracranial elastance. ICP and IOP responses to hypertension were tested by infusion of angiotensin II (15 micrograms.kg-1.min-1), and the response to hypercapnia was tested by elimination and reintegration of soda lime canisters in the breathing circuit. Intracranial elastance was increased by infusing mock cerebrospinal fluid (CSF) into the lateral ventricle (20 +/- 3 ml.h-1). Arterial hypotension induced with FE did not increase ICP. With increased intracranial elastance, the infusion rate of mock CSF had to be reduced while administering FE to avoid a rise in ICP (p < 0.05 compared with preinfusion value); this indicates a shift on the volume-pressure curve to the right. There were no indicators that cerebral autoregulation or CO2 reactivity of the cerebral vasculature were affected by FE in this anesthetized porcine model, as speculated from analysis of the time course of delta ICP. There are, however, indicators of increased intracranial elastance, most likely caused by vasodilation. Caution should hence be exercised when FE is administered to patients with increased intracranial elastance.
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PMID:Effects of fenoldopam on intracranial pressure and hemodynamic variables at normal and elevated intracranial pressure in anesthetized pigs. 791 22

Laparoscopic techniques in general surgery have become a widely accepted method, especially for treatment of symptomatic gallstone disease. Many reports have investigated the indications, contraindications, equipment, techniques and outcome of laparoscopic procedures. However, as yet, relatively few studies have discussed the problems concerning patient's monitoring and care during the postoperative course. In the present paper, the authors review the pertinent literature analyzing the management of the postoperative period after laparoscopic surgery of the upper abdomen. Obviously, most data have regarded cholecystectomy, that is the most frequent procedure. Surgical laparoscopists have utilized knowledge deriving from gynecological experience, but these procedures are generally short and performed on young, otherwise healthy female patients. On the contrary, laparoscopic digestive surgery shows both gastrointestinal and peculiar general problems. These procedures are frequently performed on older patients who may have pre-existing diseases and require longer periods of peritoneal insufflation. During surgery of the upper abdomen, the pneumoperitoneum and the patient's operative position produce haemodynamic and respiratory changes coupled with acid-base disturbances. Intraabdominal hypertension causes a venous stasis along the inferior vena caval territory that can lead to a decrease in cardiac preload and in cardiac output. Usually, a compensatory increase in peripheral vascular resistance ensures normal or mildly high values of arterial tension. Furthermore, a hypercapnia and a mild mixed acidosis can develop as a result of the concomitance of different pathogenetic factors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Postoperative course after laparoscopic surgery of the upper abdomen]. 799 Nov 66

Obstructive sleep apnoeas (OSA) exert immediate marked cardiovascular effects, and may favour the development of systemic and pulmonary hypertension in the long-term. As for the pathogenesis of the acute cardiovascular changes, the first studies high-lighted the role of OSA-induced hypoxia and mechanical changes. However, more recent work pointed to the role played by the arousal reaction terminating OSA, and to the activity of the autonomic nervous system during apnoea and inter-apnoeic phase. As for the pathogenesis of chronic cardiovascular changes, recent findings suggest that the link between OSA and systemic hypertension may be through an abnormal function of the carotid body and underline the importance of chronic intermittent hypoxia versus continuous hypoxia in the development of stable systemic hypertension. On the other hand, OSA do not appear to enhance strongly the development of stable pulmonary hypertension. In this review, we analyze OSA-induced cardiovascular changes with particular emphasis on to the interplay of the possible pathogenic mechanisms involved. Acute OSA-induced cardiovascular alterations during the apnoeic phase appear to result mainly from the mechanical effects of OSA, while during the interapnoeic phase they seem mostly determined by chemical factors (hypoxia, hypercapnia) and by the arousal reaction. In addition, the role of reflex changes elicited by resumption of ventilation should be reconsidered, since lung inflation seems to exert a positive effect on the cardiovascular changes occurring at the end of OSA. This would be in contrast with the inhibitory effects described as "lung inflation reflex", and deserves further study.
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PMID:The cardiovascular effects of obstructive sleep apnoeas: analysis of pathogenic mechanisms. 800 63

During the last 4 years, fifty-seven patients of acute severe asthma (ASA) were admitted to intensive care unit (ICU). Twenty-three patients required mechanical ventilation (MV) on 25 occasions. Indications to intubate were persistent hypoxia (PaO2 < or = 55 mm Hg) or hypercapnia with respiratory acidosis (64%), abnormal mentation (24%) and respiratory arrest (12%). All the patients were monitored for clinical features, arterial blood gases (ABG) and peak airway pressure (PAP). During MV, there was one case of pneumothorax (4%), seven (28%) cases of transient hypertension and one (4%) patient died. Mean duration of MV was 3 days and the outcome was favourable. Therefore, resorting to aggressive treatment early in the course of disease proves life saving in acute severe asthma.
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PMID:Role of mechanical ventilation in acute severe asthma. 803 18

Analysis of the first year's experience of 94 patients in a tertiary referral center showed that 21% had had previous surgery. Fifty-seven percent had medical problems: 17.8% hypertension, 16% cardiac problems, 8.9% diabetes mellitus, and 6.2% chronic renal insufficiency. Four patients had hypercarbia and were acidotic. The conversion rate to open cholecystectomy was 8.7%. Only one patient required reoperation for a bile leak. Fifty-five percent of our procedures took < or = 2 h, but 45% took > or = 3 h. Just over 50% of our patients stayed 48 h postoperatively. In this complex group of patients, it appears possible to achieve results similar to those previously published, but more time was required for surgery, and length of stay was increased.
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PMID:Laparoscopic cholecystectomy in a tertiary referral center. 811 58


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