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Biomedical subjects

P Welfringer

Publications and source records attributed to P Welfringer.

8 recordsLinked to original sources
PubMed1997

Is endotoxin and cytokine release related to a decrease in gastric intramucosal pH after hemorrhagic shock?

OBJECTIVES: (a) To investigate the relationship between gut ischemia parameters (gastric intramucosal pH [pHi], mucosal-arterial carbon dioxide difference [PCO2-gap]), and endotoxin or cytokine release during hemorrhagic shock; (b) to compare the predictive value of pHi, PCO2-gap and arterial lactate concentrations. DESIGN: Prospective study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: 20 multiple trauma patients with severe hemorrhagic shock. INTERVENTIONS: Intramucosal measurements and blood samples were obtained on admission to the emergency room and repeatedly over 48 h. MEASUREMENTS AND RESULTS: Endotoxin was measured using a chromogenic limulus amoebocyte assay. Cytokine [tumor necrosis factor-alpha (TNF alpha) and interleukin-6 (IL-6)] values were evaluated by immunoradiometric assays. Only 3 patients had positive blood cultures but endotoxins were detected at least once in all patients. Endotoxin levels were similar in survivors and non-survivors over the study period and were not related to pHi or PCO2-gap. Initially, high levels of IL-6 were observed in both nonsurvivors and survivors [median 1778 pg/ml (range 435-44,540) vs 2068 pg/ml (range 996-92,300)]. IL-6 levels progressively decreased in the survivors but not significantly. On admission, TNF alpha concentrations were similar in nonsurvivors and survivors (42 +/- 35 vs 46 +/- 27 pg/ml). From the 24th h, TNF alpha values were higher in the nonsurvivors than in the survivors (24 h: 72 +/- 38 vs 34 +/- 17 pg/ml, p < 0.05). The greatest IL-6 levels were found for a pHi < 7.20 (28.5 +/- 36.5 vs 1.8 +/- 1.3 ng/ml, p < 0.05) or a PCO2-gap > 7.5 mmHg (1 kPa) (32.5 +/- 37.5 vs 1.7 +/- 1.3 ng/ml, p < 0.01). With the same pHi threshold, no difference was found in endotoxin levels. The lactate concentrations were predictive for outcome from the 12th h (9.5 +/- 5.9 vs 3.6 +/- 2.3 mmol/l, p < 0.05). CONCLUSIONS: During severe hemorrhagic shock, endotoxin translocation from the gut was a common phenomenon that seemed independent of both pHi values and outcome. It could not explain IL-6 and TNF alpha release. In severe hemorrhagic shock, neither pHi nor PCO2-gap provides additional information to the lactate measurements.

Adult↗
PubMed1997

Differential quantitative blood cultures in the diagnosis of catheter-related sepsis in intensive care units.

The aim of this prospective study was to compare differential blood cultures and quantitative catheter tip cultures for the diagnosis of catheter-related sepsis. Over a period of 2 years, 283 central venous catheters were inserted in 190 adult patients. Catheters were removed when they were no longer needed or when infection was suspected. Immediately before removal of the central venous catheters, blood cultures were performed, with blood drawn simultaneously from the catheter and the peripheral vein. After removal, quantitative catheter culture was performed according to the Brun-Buisson modified Cleri technique. Fifty-five quantitative catheter cultures were positive. They were classified as contaminated (n = 18), colonized (n = 23), or infected (n = 14). Differential blood cultures correctly identified 13 infections. With a catheter/peripheral cfu ratio of 8, differential blood cultures had a sensitivity of 92.8% and a specificity of 98.8%. When the catheters were removed because of suspected infection, differential blood cultures had a sensitivity of 92.8% and a specificity of 100%. Differential blood culture, a technique that does not necessitate catheter removal, seems effective in the diagnosis of catheter-related sepsis in patients in the intensive care unit.

Adult↗
PubMed1992

[Clonidine premedication and isoflurane anesthesia to reduce bleeding in otologic surgery].

Seventy-seven ASA 1 patients scheduled for ear surgery were premedicated orally, 90 min before anaesthesia. They were randomly assigned to two groups, according to the drug used: hydroxyzine alone (group T, n = 39) or combined with clonidine (4.9 +/- 0.3 micrograms.kg-1) (group C, n = 38). Anaesthesia was induced with midazolam (0.3 mg.kg-1) and alfentanil (30 micrograms.kg-1). Ventilation was controlled with a 50/50 v/v mixture of oxygen and nitrous oxide (FETCO2 = 4 to 4.5%), and anaesthesia was maintained with repeated injections of alfentanil (15 micrograms.kg-1 at the start of surgery, and then every 15 min) and with isoflurane (mean end-expiratory concentration 0.6 +/- 0.3 vol %). Surgical bleeding was assessed every ten minutes on a numerical scale with four values. A bloodless surgical field was obtained by adjusting the isoflurane concentration up to 2 MAC, and by using a trinitrine infusion as required. Cardiovascular monitoring included an electrocardioscope and automatic blood pressure measurements. Before induction of anaesthesia, the blood pressure was lower in group C (84.7 +/- 11.2 vs. 95.9 +/- 106 mmHg) (p less than 0.001); the difference in heart rate was not significant (65 +/- 15 vs. 70.6 +/- 14 b.min-1). Moderate stable intraoperative hypotension was obtained in both groups. However, mean arterial blood pressure (C:65.8 +/- 7.8 mmHg; T: 73 +/- 9.4 mmHg) and heart rate (C: 53.4 +/- 6.8 b.min-1; T: 60.4 +/- 8 b.min-1) were significantly lower in the patients premedicated with clonidine (p less than 0.001). There were more periods of sinus bradycardia (heart rate less than or equal to 50 b.min-1), mostly seen before the beginning of surgery, in group C patients (p less than 0.01); atropine was also required more often (when the heart rate was less than or equal to 40 b.min-1) in this group of patients (NS). The comparative assessment of surgical field quality was in favour of group C (no troublesome bleeding) as opposed to the control group (16% troublesome bleeding); there were also more bloodless surgical fields in the former group (73.7% vs. 48.7% in group T, p less than 0.05). This study therefore demonstrated that clonidine premedication before anaesthesia with isoflurane was helpful in decreasing bleeding during ear surgery.

Adult↗
PubMed1986

[Nasopharyngeal fibroma. Excision under hemodilution and delayed autotransfusion].

The surgical treatment of juvenile naso-pharyngeal angiofibroma involved a potential haemorrhagic risk: the average intra-operative blood loss was estimated at between 1,300 and 2,800 ml in many reports. Two cases are reported in which haemodilution and autologous blood transfusion were used. The method consisted in pre-operative repeated phlebotomies ("leap-frog") and normovolaemic acute haemodilution; thus, 1,700 ml of autologous blood was collected in the first case, and 2,300 ml in the second one. Autotransfusion was carried out and no homologous blood transfusion was used in the peri-operative period. The use of this method, although compelling, had many advantages (financial saving, suppression of adverse reactions with homologous transfusion, transfusion of fresh blood, reduction of postoperative oedema).

Adult↗
PubMedDate not supplied

[Circulatory and respiratory repercussions to direct suspension laryngoscopy in the adult: value of a propofol-alfentanil combination].

The clinical effects of a propofol-alfentanil association were studied in fifteen patients ASA II (mean age 50.1 +/- 14.1) anaesthetized for E.N.T. endoscopy after informed consent. All the patients received an intramuscular premedication with 0.10 to 0.15 mg.kg-1 midazolam. Propofol 2.5 mg.kg-1 was injected in a peripheral venous line with alfentanil 10 micrograms.kg-1, followed by continuous automatic injection of propofol at a dose of 5 to 10 mg.kg.h-1 and alfentanil 5 micrograms.kg-1 given just before suspension. After induction and during maintenance of anaesthesia, the patients were allowed to breathe oxygen spontaneously O2 assisted when apneic. The following variables were studied before induction (to), after induction (t1), during suspension (t2) and when stopping the infusion (t3): haemodynamic parameters using an invasive method and blood gases. Statistical analysis was performed using the Student's test for paired samples. Surgical conditions and anaesthetic quality were good with early recovery of consciousness and return of all reflexes. After an initial period of cardio vascular depression, the haemodynamic parameters did not vary much during the anaesthesia and propofol-alfentanil appeared to limit considerably the hypertension due to laryngoscopy. However, there was a moderate degree of hypercapnia (p less than 0.001) in most patients, giving evidence of some respiratory depression and possibly a greater depth of anaesthesia than desirable. Indeed, the doses of alfentanil required seemed to be more important with propofol because of a probably interference between the two drugs; the doses of these drugs should therefore be modified according to the length of surgery.

Adult↗
PubMedDate not supplied

[Anesthesia in resections and anastomoses of the trachea].

Resections and end-to-end anastomosis have been effective in correcting localized tracheal strictures. Important clinical considerations are the precise preoperative assessment of the lesion, careful planning of anesthetic management and choice of the appropriate decision. Surgical procedures involving sharing of the air way between the anaesthetist and the surgeon impose special problems on the anaesthetist. On the one hand, the surgeon requires unrestricted access to the operating site and on the other, the anaesthetist must ensure adequate anaesthesia, oxygenation and carbon dioxide elimination, preferably without contamination of the lung fields. The more commonly employed technique is the use of a tracheal tube so that anaesthesia can be maintained using conventional IPPV. In our experience, the majority of strictures in adults can be managed as well, or better, by using a conventional endotracheal tube.

Adult↗