Biomedical subjects

J Klossner

Publications and source records attributed to J Klossner.

At least 19 recordsLinked to original sources

PubMed2002

Osteodistraction of a previously irradiated mandible with or without adjunctive hyperbaric oxygenation: an experimental study in rabbits.

The purpose of this study was to analyse the effects of irradiation and hyperbaric oxygenation (HBO) on mandibular osteodistraction (OD). Eighteen rabbits were divided into three groups: 1. Irradiation (R), 2. Irradiation+HBO (R-HO), and 3. Control group (C). Animals of groups R and R-HO received in the mandible irradiation 22.4 Gy in four 5.6 Gy fractions (equivalent to 50 Gy/25 fractions). In addition, group R-HO was given HBO at 2.5 ATA for 90 min per day 18 times preoperatively. Unilateral osteotomy was made 1 month after completion of radiotherapy. After a 1 week latency period bone distraction was started at rate of 1 mm per day, continued for 2 weeks, and left to consolidate for 4 weeks. Amount of new bone was measured histomorphometrically from midsagittal sections. Area of new bone was equal in all groups. Bone was more mature and bone spicules better organized in group C than in groups R and R-HO. Cartilaginous cells were found in distracted bone in all groups but larger chondroid islands were evident only in group R. It seems that despite delayed bone formation, OD can be performed after radiotherapy. HBO had a beneficial effect on bone quality of a previously irradiated mandible.

Animals↗

PubMed2000

Hyperbaric oxygen increases parasympathetic activity in professional divers.

The role of autonomic nervous system in hyperoxic bradycardia was evaluated by using the power-spectral analysis of heart-rate variability (HRV). Ten professional divers went through two hyperbaric hyperoxic experiments: (1) hyperbaric oxygen (HBO), 100% oxygen at 2.5 ATA, (2) hyperbaric air (HBAIR), O(2) 21% at 2.5 ATA. Four-minute traces of ECG were registered and subjected to power-spectral analysis. Cardiac conduction parameters were evaluated by a diagnostic 12-lead ECG and arrhythmias by a continuous 3-lead ECG. Statistical analysis was made using analysis of variance for repeated measurements. Heart rate decreased (P < 0. 001), but the response was similar during both treatments (P=0.14). Total power increased significantly more during HBO than HBAIR (P=0.003). High-frequency (HF) power (P < 0.001), Hayano's index (P=0.001) and normalized units of HF power (P=0.002) increased and LF/HF index (P < 0.001) decreased more during HBO than HBAIR. There were no changes in cardiac conduction or incidence of arrhythmias. In conclusion, 100% oxygen at 2.5 ATA caused marked increase in parasympathetic tone compared with 21% oxygen at 2.5 ATA.

Analysis of Variance↗

PubMed1999

Heart rate variability in healthy volunteers during normobaric and hyperbaric hyperoxia.

Inhaled supranormal partial pressure of oxygen induces bradycardia and peripheral vasoconstriction. The exact mechanism of the decreasing heart rate is not clear, but the autonomic nervous system is partly involved. In the present study the role of the autonomic nervous system in hyperoxic bradycardia was evaluated by using the power spectral analysis of heart rate variability. Ten healthy volunteers participated in four experiments: (i) hyperbaric oxygen treatment (100% oxygen at 2.5 ATA), (ii) hyperbaric air treatment (O2 21% at 2.5 ATA), (iii) oxygen treatment at normal pressure (100% O2, 1 ATA) and (iv) air breathing at normal pressure (21% O2, 1 ATA). During the experiments, ECG was registered and subjected to power spectral analysis. The volunteers rated their perception of temperature, ear discomfort, sweating and excitement on a visual analogue scale. Statistical comparison of the results of the four trials was conducted with a two-way ANOVA for repeated measurements. Heart rate decreased during all interventions, but there were no statistically significant differences between the sessions. High frequency variability of heart rate variability and Hayano's index of HF power increased and LF/HF ratio decreased with increasing partial pressure of oxygen. Our results suggest, that normobaric and hyperbaric hyperoxia increase parasympathetic influence in the regulation of the heart.

Adult↗

PubMed1999

Effect of hyperbaric conditions on plasma stress hormone levels and endothelin-1.

To study a generalized stress reaction as well as endothelin-1 concentrations during moderate hyperbaria and hyperbaric oxygen (HBO2), eight professional divers were exposed to air (O2 21%, AIR) and oxygen (O2 100%, HBO2) at 2.5 atm abs for 60 min in separate sessions. Plasma concentrations of epinephrine, norepinephrine, dihydroxyphenylglycol (metabolite of norepinephrine), cortisol, ADH, renin, aldosterone, pro-ANP, and endothelin-1 were analyzed before, during, and 20 min after the treatments. Endothelin-1 increased significantly (6% during HBO2 and 18% during AIR, and 30 and 34% after the treatments, respectively, P = 0.032). There was no statistically significant difference in the changes of mean norepinephrine and dihydroxyphenylglycol levels between the treatments, although both seemed to change slightly during the treatments, but not over the baseline (time effect P = 0.031 and P = 0.011, respectively). Cortisol levels decreased significantly (P = 0.001) during the treatments. No significant changes were found in other analyzed hormones. The authors concluded that a) HBO2, and hyperbaric air at 2.5 atm abs do not induce a generalized hormonal stress reaction, and b) endothelin-1 increases during HBO2 and hyperbaric air at 2.5 atm abs.

Aldosterone↗

PubMed1999

Management of clostridial gas gangrene and the role of hyperbaric oxygen.

BACKGROUND AND AIMS: Clostridial gas gangrene is one of the most dreaded infections in surgery. The aim of this study was to investigate the efficacy of surgery, antibiotic treatment, surgical intensive care and especially the role of hyperbaric oxygen in the management of clostridial gas gangrene. MATERIAL AND METHODS: 53 patients, 42 of them submitted from other hospitals in Finland. After the diagnosis had been made the patients underwent surgical debridement, broad spectrum antibiotic therapy and a series of hyperbaric oxygen (HBO) treatments at 2.5 ATA pressure. The necrotic tissue was excised and incisions were made in the affected areas. Amputations were performed when necessary. RESULTS: Twelve patients died (22.6%). Hyperbaric oxygen therapy decreased the systemic toxicity and prevented further extension of the infection thereby improving the overall outcome of the patients. CONCLUSION: Hyperbaric oxygen therapy of gas gangrene seems to be life-, limb- and tissue saving. Early diagnosis remains essential. Patient survival can be improved if the disease is recognized early and appropriate therapy applied promptly. Surgical and antibiotic therapy as well as HBO treatment combined with surgical intensive care must be started as soon as possible.

Adult↗

PubMed1997

Enalaprilat decreases plasma endothelin and atrial natriuretic peptide levels and preload in patients with left ventricular dysfunction after cardiac surgery.

OBJECTIVE: To study the acute effects of angiotensin-converting enzyme inhibition by intravenous enalaprilat infusion in patients with left ventricular dysfunction after cardiac surgery. DESIGN: Prospective, consecutive sample, before-after trial. SETTING: Surgical intensive care unit in a tertiary care university hospital. PARTICIPANTS: Eight patients with left ventricular dysfunction after cardiac surgery. Patients were defined as having left ventricular dysfunction if the pulmonary capillary wedge pressure persisted above 18 mmHg in spite of conventional vasoactive medication (inotropic or vasodilating and diuretic drugs) and intermittent mandatory ventilation during the first postoperative week. INTERVENTIONS: Enalaprilat was infused initially at 1 mg/ hour. The rate was doubled every 30 minutes until pulmonary capillary wedge pressure decreased at least 20% or until a maximum total dose of 10 mg was achieved. MEASUREMENTS AND RESULTS: Central hemodynamics, systemic oxygenation, and hormonal regulation of circulation (plasma renin activity, plasma endothelin, atrial natriuretic peptide, norepinephrine, epinephrine, and vasopressin concentrations, serum angiotensin-converting enzyme activity, and serum levels of aldosterone) were assessed at baseline before enalaprilat infusion, and repeatedly over 2 hours after the infusion. Enalaprilat infusion (median dose, 2.0 mg; infusion time, 48 minutes) caused a significant decrease in pulmonary capillary wedge pressure (p = 0.004), lasting until the end of the 2 hours' follow-up. This coincided with inhibition of serum angiotensin-converting enzyme activity (p < 0.001), an increase in plasma renin activity (p = 0.022), and decreases in plasma endothelin (p = 0.035), atrial natriuretic peptide (p = 0.005), and serum aldosterone (p = 0.001) concentrations. Cardiac output, venous admixture, and oxygen delivery and consumption remained unchanged. CONCLUSIONS: Adding enalaprilat to conventional therapy makes it possible to unload the left ventricle and to relieve overt neurohormonal activation temporarily while maintaining cardiac function and systemic oxygenation.

Adult↗

PubMed1995

A modified protocol to treat early osteoradionecrosis of the mandible.

Hyperbaric oxygen (HBO) increases oxygen availability to hypoxic tissues thereby inducing fibroblastic proliferation and capillary formation in bone and soft tissue. From 1981 to 1991 we used a monoplace hyperbaric chamber, and since 1992 a multiplace chamber, for HBO treatments. HBO was given at 2.5-2.8 atm abs for 90-120 min, once per day. We used five to seven preoperative and five to seven postoperative sessions. Altogether, 17 patients with osteoradionecrosis (ORN) of the mandible or maxilla were treated with surgery and HBO. Surgical therapy consisted of decortication of the affected bone that was subsequently covered with a free periosteal transplant from the tibia. The shortest follow-up time is 18 mo. Sixteen patients have remained symptom free after the first treatment period. One case was a failure in the early protocol but was successfully treated using a free microvascular flap. It is concluded that HBO is a promising adjunct to surgery in treating mandibular or maxillary ORN.

Adult↗

PubMed1994

Aspoxicillin versus piperacillin in severe abdominal infections--a comparative phase III study.

We compared aspoxicillin, a new broad-spectrum penicillin derivative, with piperacillin in severe abdominal infection. Aspoxicillin 4 g administered tds (n = 52) or piperacillin 4 g qds (n = 53) usually as monotherapy were randomly given to patients suffering from perforated appendicitis, acute cholecystitis, ulcer or colon perforation, or intra-abdominal abscess. Blood, tissue and exudate cultures were obtained when applicable for pathogen identification and susceptibility testing. The efficacy rates were similar in the two study groups. Of the 50 evaluable aspoxicillin patients 45 (90%) were considered as treatment responders compared with 48 patients out of 53 (91%) in the piperacillin group (NS). The 95% confidence interval for the efficacy difference was -12% to +11% thus showing no difference between the two drugs. Both drugs were generally well tolerated and no serious drug-related adverse events were noted. However, five patients died because of their illness and one patient had a fatal myocardial infarction. In conclusion, aspoxicillin 4 g tds was shown to be equal to piperacillin 4 g qds in severe abdominal infections.

Abdominal Abscess↗

PubMed1988

Anaesthesia for cardioversion: a comparison of propofol and thiopentone.

Propofol (2,6-diisopropylphenol) 2.5 mg.kg-1 IV was compared with thiopentone 5 mg.kg-1 IV as an induction agent in anaesthesia for elective cardioversion. Thirty-five patients (ASA physical status II-III) with atrial fibrillation were included. Thirty patients were randomized to receive propofol or thiopentone. Five patients were treated twice during the study period and anaesthetized with both agents (the first treatment according to the random order and the second with the agent not used on the first occasion). The induction characteristics and the haemodynamic response for propofol and thiopentone were similar. The success rate of cardioversion did not differ between the groups. Recovery times were shorter after propofol than after thiopentone with respect to ocular muscle balance, central integration and subjective sedation of patients. The incidence of side-effects did not differ between the groups. None of the patients reported any awareness during the procedure. All five patients treated twice (with both agents) assessed the anaesthetic procedure with propofol as being more pleasant than that with thiopentone.

Anesthesia, Intravenous↗

PubMed1988

Continuous positive airway pressure with and without high-frequency ventilation: hemodynamics, oxygenation, and endocrine response.

After 18 h of mechanical ventilation following open heart surgery, central hemodynamics, systemic oxygen delivery (DO2), and oxygen consumption were assessed in ten consecutive patients receiving continuous positive airway pressure (CPAP) therapy. Plasma vasopressin, norepinephrine, and epinephrine levels were analyzed. While maintaining the mean airway pressure, two CPAP methods were studied: a demand CPAP with continuous flow without (CPAP) and one with high-frequency ventilation (CPAP-HFV). The frequency used during CPAP-HFV was 300 cycle/min. The spontaneous ventilatory rate was found to be equal during CPAP and CPAP-HFV. The cardiac and stroke volume indices were slightly higher (p less than .05) during CPAP-HFV, which accounted for the finding that DO2 was also slightly higher (p less than .05) during CPAP-HFV. The epinephrine and norepinephrine levels did not differ, whereas the vasopressin level was somewhat higher during CPAP-HFV, which might indicate a higher level of vigilance. It is concluded that cardiac output was slightly higher during CPAP-HFV compared to that during CPAP. This may be due to an effect of the oscillations on circulation or to differences in the level of vigilance.

Aged↗

PubMed1986

Branched chain amino acid enriched parenteral nutrition in surgical intensive care patients.

The metabolic responses to branched chain amino acid enriched total parenteral nutrition were studied in surgical intensive care patients with documented severe catabolism. Twenty-four patients were randomised to receive total parenteral nutrition with either 50% (BCAA) or 15% (CONTROL) of its amino acid content as branched chain amino acids. The daily intake of nitrogen was 0.24 g per kg b. wt and that of energy, at steady state, 45 kcal per kg b. wt. Total parenteral nutrition resulted in similar nitrogen balances (Day 1 BCAA: -0.07 +/- 0.09, CONTROL: -0.05 +/- 0.10; Day 4 BCAA: -0.12 +/- 0.07, CONTROL: -0.06 +/- 0.09; Day 5 BCAA: -0.07 +/- 0.08, CONTROL: -0.05 +/- 0.08 g/kg b. wt day; mean +/- S.D.) in both treatment groups throughout the study. The urinary excretion of 3-methylhistidine was higher before feeding in the control group but the rates were similar during total parenteral nutrition in both groups. There were no differences between the groups in the decrease of serum prealbumin during the study. We conclude that the proposed benefits, if any, from enriching nutritional regimens with branched chain amino acids are unlikely to be of major therapeutic relevance in severe catabolism.

Journal Article↗

PubMed1985

Hypophosphatemia in hypercatabolic patients.

Twenty-four hypercatabolic surgical intensive care patients were treated with a daily phosphate dosage of 0.5 mmol/kg b.wt during the postoperative total parenteral nutrition (TPN). The adequacy of this regimen was evaluated by measuring the plasma phosphate concentration before and after five days of TPN. All the patients were in negative nitrogen balance throughout the study. Ten of them were hypophosphatemic at the beginning, while none was hypophosphatemic at the end of the study. Hyperphosphatemia was observed once, at the end of the study. The catabolic surgical patient receiving parenteral nutrition is at risk of hypophosphatemia, and particularly vulnerable to its consequences. A daily dosage of 0.5 mmol/kg b.wt of phosphate appeared adequate in covering the increased requirements of these patients.

Humans↗

PubMed1981

Bioavailability of rectal aspirin in neurosurgical patients.

Serum salicylate levels were determined fluorimetrically in 12 neurosurgical patients after rectal and oral administration of 1.0 g aspirin. There was no significant difference in the AUC-value between the two routes of administration, but a slower rate of absorption with no clear peak effect was found after rectal administration. Rectal aspirin is useful in clinical situations in which mediation is difficult by the oral route, e.g. after neurosurgical and open-heart surgical interventions.

Administration, Oral↗

PubMed1981

Central haemodynamics and oxygen transport during CPAP with and without mandatory ventilations.

Ten patients, subjected 16 h earlier to open-heart surgery (aortocoronary bypass and/or aortic valve replacement), were studied during the weaning period after postoperative mechanical ventilation. Central haemodynamics and oxygen transport were assessed along with total oxygen consumption during continuous positive airway pressure with four mandatory ventilations per minute (mode CPAP + IMV) and, subsequently, during CPAP alone. During the two modes of ventilation, airway pressure was adjusted to be equal during the spontaneous inspiratory phases. All parameters of haemodynamics, oxygenation and oxygen consumption were found to be essentially satisfactory and unchanged during both modes of ventilation. Our observations suggest that, as the parameters studied were unaltered with the change from CPAP + IMV to CPAP, the use of ventilatory support for these patients during the weaning period (in the form of four mandatory ventilations per minute) appears, in terms of central haemodynamics and oxygen transport, to be well tolerated in cases where adequate spontaneous ventilation is in doubt.

Adult↗

PubMed1981