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Biomedical subjects

G Perrin

Publications and source records attributed to G Perrin.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Dopexamine: a new dopaminergic agonist].

Dopexamine hydrochloride is a new synthetic catecholamine for intravenous use in low cardiac output states with co-existing raised systemic or pulmonary vascular resistance. Dopamine has been commonly used since several years in these situations. The drawbacks of dopamine include a vasoconstrictive effect with high infusion rates, and a marked tendency for ventricular ectopy due to the potent beta-1 adrenergic stimulation. Dopexamine hydrochloride has interesting vasodilator properties, with marked intrinsic agonist activity at beta-2 adrenoreceptors and a lesser agonist activity at dopaminergic receptors (DA1 and DA2). Its mild inotropic activity arises primarily from baroreceptor reflex stimulation with a possible contribution from direct stimulation of myocardial beta 2-adrenoreceptors. Dopexamine hydrochloride is responsible for an inhibition of neuronal re-uptake of catecholamines (uptake-1), producing an indirect stimulation of cardiac beta 1-receptors. This catecholamine has no effect at alpha 1 and alpha 2-adrenoreceptors, and only very weak and clinically insignificant beta 1-adrenoreceptor agonist activity. Dopexamine hydrochloride improves cardiac performance by a marked vasodilation and a mild inotropic activity. The specific activity at dopaminergic receptors increases cerebral, myocardial, splanchnic and renal blood flows. These haemodynamic effects are associated with an increase in diuresis and natriuresis. These benefits are achieved without side effects such as an increased myocardial oxygen consumption, although induced tachycardia may be responsible for chest pain/anginae pain in patients with ischaemic heart disease. In clinical practice, dopexamine hydrochloride is easy to use; the short plasma half-life (6 minutes in healthy volunteers and 11 minutes in patients with low cardiac output) allows a rapid return to pretreatment status at discontinuation of the infusion. Preliminary studies have shown that dopexamine hydrochloride can produce beneficial effects in patients with acute heart failure or with compromised left ventricular function following cardiac surgery. The drug has also been assessed in patients with septic shock, most often in association with dopamine or norepinephrine. In these patients, dopexamine produces a dose-related increase in cardiac index, stroke volume, heart rate and a decrease in systemic vascular resistance. Its use in this indication must be cautious, particularly in patients with hypotension or decreased venous return. Comparative therapeutic trials are clearly required to establish the efficiency and tolerance of dopexamine hydrochloride in comparison with dopamine and dobutamine, before its place in therapy can fully be defined.

Adrenergic Agonists↗
PubMed1993

Effect of bolus doses of midazolam on intracranial pressure and cerebral perfusion pressure in patients with severe head injury.

We have studied the effects of bolus doses of midazolam 0.15 mg kg-1 i.v. on intracranial pressure (ICP), mean arterial pressure (MAP) and cerebral perfusion pressure (CPP) in 12 patients with severe head injury (Glasgow Coma Scale score < or = 6). The study was performed in patients aged 17-44 yr who were sedated (phenoperidine 20 micrograms kg-1 h-1) and paralysed (vecuronium 2 mg h-1). Midazolam reduced MAP from 89.0 mmHg to 75.0 mmHg (P < 0.0001), while CPP decreased from 71.0 mmHg to 55.8 mmHg (P < 0.0001). During the study, CPP decreased to less than 50 mmHg in four patients. Midazolam induced small, non-significant changes in ICP. However, when control ICP was less than 18 mmHg (n = 7 patients), an increase in ICP was observed. The remaining five patients (control ICP > or = 18 mmHg) exhibited a slight decrease in ICP. These findings suggest that bolus administration of midazolam should be performed with great caution in patients with severe head injury, especially when ICP is less than 18 mmHg.

Adolescent↗
PubMed1993

Norepinephrine or dopamine for the treatment of hyperdynamic septic shock?

STUDY OBJECTIVE: To compare the ability of dopamine and norepinephrine to reverse hemodynamic and metabolic abnormalities of human hyperdynamic septic shock. DESIGN: Prospective, double-blind, randomized trial. SETTING: An ICU in a university hospital. PATIENTS: Adult patients with hyperdynamic septic shock after fluid resuscitation. INTERVENTIONS: Patients were assigned to receive either dopamine (2.5 to 25 micrograms/kg/min) or norepinephrine (0.5 to 5.0 micrograms/kg/min). If hemodynamic and metabolic abnormalities were not corrected with the maximum dose of one drug, the other was added. MEASUREMENTS AND RESULTS: The aim of therapy was to achieve and maintain for at least 6 h all of the following: (1) systemic vascular resistance index > 1,100 dynes.s/cm5.m2 and/or mean systemic blood pressure > or = 80 mm Hg; (2) cardiac index > or = 4.0 L/min/m2; (3) oxygen delivery > 550 ml/min/m2; and (4) oxygen uptake > 150 ml/min/m2. With the use of dopamine 10 to 25 micrograms/kg/min, 5 of 16 patients (31 percent) were successfully treated, as compared with 15 of 16 patients (93 percent) by norepinephrine at a dose of 1.5 +/- 1.2 micrograms/kg/min (p < 0.001). Ten of 11 patients who did not respond to dopamine and remained hypotensive and oliguric were successfully treated with the addition of norepinephrine. CONCLUSIONS: At the doses tested, norepinephrine was found, in the present study, to be more effective and reliable than dopamine to reverse the abnormalities of hyperdynamic septic shock. In the great majority of the study patients, norepinephrine was able to increase mean perfusing pressure without apparent adverse effect on peripheral blood flow or on renal blood flow (since urine flow was reestablished). At the same time, oxygen uptake was increased.

Dopamine↗
PubMed1993

Management of nonfunctioning pituitary adenomas.

Clinically nonfunctioning pituitary adenomas represent one-third of pituitary tumours submitted to surgery. Symptoms consist mainly of visual impairment and there is no evidence of hormonal hypersecretion. Most nonfunctioning pituitary adenomas express genes of glycoprotein hormone subunit(s), and release these hormones in vitro. Thirty per cent of tumours do not synthesize any recognizable pituitary hormones. The first-line treatment is surgery, with the aim of removing as much of the tumour as possible and of reducing visual defects without excessive risks 80% of patients show visual improvement postoperatively. Tumour remnants exist in 30 to 50% of cases; radiation therapy is applied when tumour removal is incomplete. Recurrence of tumour and visual signs and/or an increase in the size of the tumour is noted in about 20% of cases even after radiation therapy. Medical treatment is used when tumour resection is impossible or hazardous. Long-term dopamine agonist treatment in a few cases can induce rapid and partial improvement and small decrease in tumour size in about 15%. Somatostatin analogues can induce an early visual improvement in limited cases, but little visible tumour shrinkage. GnRH analogues have been used in gonadotrophin-secreting tumours; super agonists seem unable to reduce secretion and tumour size.

Adenoma↗
PubMed1992

Monitoring of central venous oxygen saturation versus mixed venous oxygen saturation in critically ill patients.

Continuous monitoring of mixed venous (SvO2) and central venous (ScO2) oxygen saturation was compared in 7 critically-ill patients (Apache II score: 19 +/- 2.1) to determine whether or not information derived from ScO2 were reliable in clinical practice. Patients were catheterized with both a pulmonary artery (PA) and a central venous (CV) catheter, each of them mounted with fiberoptic sensors (Opticath PA Catheter P7110 and Opticath CV Catheter U440, Abbott). A total of 580 comparative measurements were obtained during periods without and with therapeutic interventions (drug-titration, bronchial suction, use of PEEP, changes in FiO2 ...). The systematic error between the 2 measurement techniques was 0.6% and 0.3% in periods with and without therapeutic interventions, respectively. The variability between the 2 techniques was 10% for both periods. Differences between the values were greater than or equal to 5% in 49% of values during periods of stability and in 50% of values during periods with therapeutic interventions. There were poor correlations between the values during periods without (r = 0.48) and with therapeutic interventions (r = 0.62). Better, but still less than ideal, correlations were obtained with changes in SvO2 and ScO2 during periods without (r = 0.70) and with therapeutic interventions (r = 0.77). Although there is a need to develop a simple technique to monitor mixed venous oxygen saturation, the present study indicates that ScO2 monitoring was not reliable in the study patients.

Adult↗
PubMed1992

Performance evaluation of three vaporizing humidifiers and two heat and moisture exchangers in patients with minute ventilation > 10 L/min.

STUDY OBJECTIVE: To compare the thermal and humidification capacity of three heated hot water systems (HHWSs) and two heat and moisture exchangers (HMEs) in ICU patients submitted to minute ventilation > 10 L/min. DESIGN: Prospective, controlled, randomized, not blinded study. SETTING: ICU of a university hospital. PATIENTS: ICU patients requiring controlled mechanical ventilation with minute ventilation > 10 L/min. Patients had to be sedated and paralyzed and had to require ventilation for more than four days. INTERVENTIONS: Following a randomized order, the patients were ventilated for 24-h periods with three HHWSs (Bennett Cascade 2 humidifier, Fisher-Paykel MR 460 and MR 600) and two HMEs (Pall Ultipor and Hygrobac filter). MEASUREMENTS AND RESULTS: In each patient and for each 24-h period, absolute humidity, (AH), relative humidity (RH) of inspired gases, and tracheal temperature were obtained. Two HHWSs (Bennett and Fisher-Paykel MR 460) had a better thermal and humidification capacity than any other systems (p < 0.001). The hydrophobic HME (Pall filter) had a poor thermal and humidification capacity (RH: 79 +/- 8.7 percent; AH: 20.6 +/- 2.3 mg H2O/L). The hygroscopic filter (Hygrobac filter) had better thermal and humidification capacity than the Pall filter (RH: 92.5 +/- 3.6 percent; AH: 29.1 +/- 1.8 mg H2O/L; p < 0.001). Tracheal temperature was well preserved by all systems. The thermic and humidification capability of the Hygrobac filter declined over 24 h. Since the Pall filter could not achieve an AH > 25 mg H2O/L in any patient, it was not studied beyond the first measurement. CONCLUSIONS: The Hygrobac filter had a thermal and humidification capability closed to the two HHWSs (81 to 97 percent) but the capability declines over 24 h. The Pall filter had a poor capability (54 to 74 percent of that of HHWSs).

Adolescent↗
PubMed1992

Safety of interventional rigid bronchoscopy using intravenous anesthesia and spontaneous assisted ventilation. A prospective study.

STUDY OBJECTIVE: To investigate the safety of total intravenous anesthesia and spontaneous assisted ventilation during interventional rigid bronchoscopy (IRB). DESIGN: Prospective, noncomparative study. SETTING: A university hospital thoracic endoscopy and laser center. PATIENTS: Eighty-three patients underwent a total of 124 procedures (including Nd:Yag laser therapy, stent insertions, transbronchial biopsies/bronchoalveolar lavages (TBB/BALs) in transplant patients and others). Results of preanesthesia consultation, endoscopic and anesthesia intervention, perioperative complications, and time spent in recovery room were recorded prospectively. RESULTS: Respiratory complications occurred in 22 procedures (18 percent) and included severe intraoperative or postoperative oxyhemoglobin desaturations (19 cases), bronchospasms/laryngospasms (two cases), and one recurrent pneumothorax. These complications were mostly related to the endobronchial surgical procedure. Respiratory complications occurred more frequently in patients with American Society of Anesthesiologists (ASA) 3 and 4 status (p < 0.005) and in patients with a karnofsky Performance Scale (KPS) below 70 (p < 0.05). No cardiac complications were noted, although 13 patients had significant underlying heart disease. Propofol was used in 121 procedures. Etomidate was used 15 times for induction and three times for both induction and maintenance in patients with ASA status 4 or low blood pressure before induction. CONCLUSION: Total intravenous anesthesia and spontaneous assisted ventilation is a well-suited technique for IRB. Severe hypoxemia, however, may occur in approximately 15 percent of patients. This complication is usually related to the procedure itself and is easy to reverse. Propofol is well tolerated in the majority of patients but it must be used with care in patients with poor functional or cardiovascular status.

Adolescent↗
PubMed1992

Results of surgical treatment for cervicobrachial neuralgia. A retrospective study of 122 patients with long-term follow-up.

Surgical nerve root decompression is rarely needed in the treatment of cervicobrachial neuralgia. In patients with prolonged and resistant pain or neurological deficits, or when signs of associated spinal cord suffering have been found, various surgical procedures can be used, but is most cases the disco-arthro-radicular conflict can be solved by the anterior approach with or without bone graft. This review of long-term résults in a series of 122 patients operated upon and re-examined more than 3 years later shows that the radicular symptoms were relieved in 95% of the cases. Evaluation of anatomical results did not reveal any instability or aggravation of discarthrosis at the site of surgery. However, in 30% of the cases disc degeneration was increased in the over- and underlying levels but without recurrence of clinical symptoms; 4% of the patients in this series were reoperated upon for this aggravated or de novo disc disease. The authors underline the importance of a thorough radioanatomical examination not only to decide whether or not a "soft hernia" or an arthrotic hypertrophy should be operated, but also to evaluate the extent of the decompressive operation to be performed.

Adult↗
PubMed1991

Surgical outcome and pathological effects of bromocriptine preoperative treatment in prolactinomas.

The case histories of 40 patients with prolactinomas were retrospectively reviewed. Twenty patients treated preoperatively with bromocriptine were compared to 20 untreated patients. The two groups were comparable according to tumor size and sex. All the patients had an immuno-cytochemically confirmed prolactin adenoma. They were operated on by a transsphenoidal approach. Intraoperative findings were studied. The surgical cure rates (serum PRL level less than 30 micrograms/l) of the bromocriptine-treated group were higher than those of the control group, both in microprolactinomas (87.5% vs 50%) and macroprolactinomas (33% vs 17%). This improvement of surgical success rate may not be due solely to bromocriptine. Surgical cure also depends on preoperative serum PRL levels (less than 500 micrograms/l) and tumoral size (less than grade II0). Tumoral tissue remained in all cases. No increase in fibrosis was observed. By inducing tumoral shrinkage, bromocriptine makes surgical removal of macroprolactinomas easier and safer. This tumoral shrinkage could be explained not only by reduction of cell size, but also by decrease in intratumoral hemorrhage. Preoperative bromocriptine treatment does not adversely affect surgical outcome. Moreover, it may be useful in cases of macroprolactinomas with suprasellar extension.

Adult↗
PubMed1991

[Idiopathic giant cell granulomas of the pituitary gland. Apropos of 2 cases].

Two cases are reported of two women who had developed progressive hypopituitarism without visual disturbances. Pituitary tumors were evoked by radiological findings. The patients underwent surgical removal of invasive intrasellar tumor by transphenoidal route. Giant-cell granuloma was histologically demonstrated with negative special staining for tuberculosis acid-fast bacilli, bacteria and fungi. Secondary granuloma due to tuberculosis, brucellosis or neurosarcoidosis was ruled out by serological grounds. The prognosis was discusses through a follow-up of 7 years in the first case and 7 months in the second one. The appropriately documented 31 cases collected from the literature were compared with our two cases.

Adult↗
PubMed1990

[Risk of thrombosis in prolonged catheterization of the radial artery: comparison of 2 types of catheters].

The thrombosis rate after long-term cannulation of the radial artery was assessed prospectively in 48 intensive care patients randomly assigned to groupe A (polyethylene Leader-Cath 115-09 catheter; n = 50, aged 55 +/- 20 years, 74% male patients) or groupe B (Teflon Viggo Floswitch 4441 catheter; n = 48, aged 58.6 +/- 16 years, 73% male patients). Bedside angiography was carried out with 10 to 15 ml Hexabrix before removal of the catheter. The two groups were similar with regard to anthropometric parameters, used drugs, pathological events during the stay in ICU, arterial cannulation technique and its duration. There was no case of clinically significant ischaemia. The rate of X-ray total arterial thrombosis was 20% in group A, and 2% in group B (p less than 0.01). There was no difference in the rate of partial thrombosis (54% vs. 41.7% respectively, NS) and of lack of thrombosis (26% vs. 56.3% respectively, NS). The overall rate of thrombosis was greater in group A than in group B, but not significantly (74% vs. 43.7% respectively). The duration of arterial cannulation did not influence the rate of thrombosis. However it was higher in males of Group A than in those of Group B (p less than 0.01), when heparin was not given (p less than 0.05); when vaso-active drugs were used (p less than 0.05); and when the time required for cannula insertion was greater than 5 min (p less than 0.01). It is concluded that Teflon catheters are more biocompatible than polyethylene catheters.

Adult↗
PubMed1990

Heat and moisture exchangers and vaporizing humidifiers in the intensive care unit.

A prospective, randomized, controlled study was undertaken to compare the Pall Ultipor breathing circuit filter (PUBCF), a heat-and-moisture exchanger, and heated hot water systems (HHWSs) in ICU patients submitted to controlled mechanical ventilation. Humidification of inspired gas and bacterial contamination of breathing circuits were evaluated. During the study, there were six episodes of tracheostomy tube (TT) occlusion in six patients included in the PUBCF group. No patient out of 42 included in the HHWS group experienced this complication (p less than 0.01). There were 4 percent of days with thick and tenacious bronchial secretions in the PUBCF group and no case in the HHWS group (p less than 0.02). In the PUBCF group, 23 percent of days with hypothermia were noted as opposed to 12 percent in the HHWS group (p less than 0.01). Fewer breathing circuits were found to be contaminated in the PUBCF group (11 percent) than in the HHWS group (54 percent, p less than 0.01). In patients with an organism growing in bronchial specimens, the same organism was found to contaminate the breathing circuit in 10 percent of cases in the PUBCF group and 77 percent of cases in the HHWS (p less than 0.01). We conclude that, in the conditions of this study, the PUBCF did not provide sufficient humidification of inspired gas in ICU patients. Protection against contamination of breathing circuits was effective, but 10 percent of patients remained at risk for this complication.

Adult↗
PubMed1990

[Normal and tumorous human gonadotropic cells].

Gonadotropic cells are scattered in the anterior and tuberal lobes and make up 10 to 20% of the anterior pituitary cells. Having a morphofunctional plasticity, they secrete FSH and LH, most often simultaneously. These hormones are stored together in the granulations. In addition, under the action of regulating factors, especially GnRH, the cells can secrete one hormone or the other, or even the alpha subunit. Gonadotropic adenomas range third in frequency among operated pituitary adenomas (12% in our series). The diagnosis is based on the presence of at least 5% of immunoreactive cells with specific antibodies to gonadotropic hormones. These adenomas are distributed into 3 major types: FSH-LH adenoma, the most frequent one, FSH adenoma and alpha-subunit adenoma. The LH adenoma and the beta FSH and beta LH adenomas are very rare. Tumoral gonadotropic cells lose their morphofunctional differentiation. They also lose, to an extent varying according to the cases, their control mechanisms as well as their capacity of synthesis and excretion of both subunits. The alpha subunit, the oldest one in ontogeny, remains the most often and longest-secreted substance. There is a continuum from the gonadotropic adenoma with high plasma gonadotropins levels to the non-functioning adenoma.

Adenoma↗