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Biomedical subjects

R Kuhlen

Publications and source records attributed to R Kuhlen.

At least 37 records · Page 2Linked to original sources
PubMed2004

[Neuromonitoring with S-100 protein in the intensive care unit].

During the last years biochemical neuromonitoring with various molecules such as S-100 protein has become popular. A huge number of investigations both experimental and clinical have been undertaken to determine diagnosis and prognosis of patients with acute neurologic diseases. This article gives a review on the current knowledge, indications and limitations on the use of S-100 protein with regard to most of the acute neurological diseases an intensivist is confronted with in everyday practice.

Brain Injuries↗
PubMed2004

[Analgesia and sedation in intensive care medicine].

Sedation and analgesia are relevant aspects for the adequate treatment of patients in an intensive care unit. Recent drug developments and new strategies for ventilation provide improved sedation management allowing better adaptation to the clinical background and individual needs of the patient. This article provides an overview on the application of different substance groups. Focus is placed on newly developed pharmaceuticals such as dexmedetomidine. Another aspect is scoring system-related and EEG-based monitoring of depth of sedation. Modern concepts of analgesia and sedation for ICU patients have been developed based on the interaction of different parameters such as adaptive sedation and analgesia management (ASAM).

Analgesia↗
PubMed2004

Factors independently associated with increased risk of pain development after ophthalmic surgery.

BACKGROUND AND OBJECTIVE: Little has been documented about the development of pain after ophthalmic surgery. This study was designed to assess the incidence and severity of postoperative pain following ophthalmic surgery, and to identify key factors independently associated with development of such pain. METHODS: In a prospective, observational cohort study, 500 patients undergoing elective ophthalmic surgery were examined by assessing numerical analogue scales and analgesic requirements. RESULTS: Depending on anatomical location of surgery, operations could be classified into creating 'more severe' or 'less severe pain'. Patients undergoing posterior segment, corneal and muscle surgery exhibited the highest numerical analogue scale scores (risk ratio 4.5, 95% CI 3.01-6.79, P < 0.0001). Anterior segment surgery, which per se did not create much pain, resulted in significantly more pain when performed under general anaesthesia compared to regional anaesthesia (risk ratio 6.52, 95% CI 2.33-18.2, P < 0.0001). No other factors independently associated with an increased risk of developing serious postoperative pain could be identified. CONCLUSIONS: Patients undergoing certain ophthalmic operations, especially if performed under general anaesthesia, are more likely to experience serious postoperative pain.

Adult↗
PubMed2004

[Propofol-LCT versus propofol-MCT/LCT with or without lidocaine - a comparison on pain on injection].

OBJECTIVE: A disadvantage of Propofol (commercial preparation containing long-chain triglycerides; Propofol-LCT) is pain on injection, which is reported by 54 - 100 % of the patients. Many different approaches have been used in an attempt to decrease the pain on injection of propofol. The currently most efficacious treatment is lidocaine given intravenously with a tourniquet prior to Propofol injection. In previous studies, larger concentrations of free propofol in the aqueous phase of an emulsion were associated with more pain on injection. A new formulation of propofol (a mixture of long-chain and medium-chain triglycerides in the carrier emulsion; Propofol-MCT/LCT) reduces the incidence of pain on bolus injection. This study was designed to investigate, whether the use of Propofol-MCT/LCT alleviates pain on injection to a similar degree as pretreatment with lidocaine. METHODS: Eighty patients (ASA I - III) were randomly assigned to four groups according to a double-blinded protocol, to receive either lidocaine 2 % or normal saline given iv. with a 60 seconds tourniquet time before the injection of Propofol-LCT or Propofol-MCT/LCT. (group 1: 2 ml NaCl 0,9 %, Propofol-LCT; group 2: 2 ml NaCl 0,9 %, Propofol-MCT/LCT; group 3: 2 ml lidocaine 2 %, Propofol-LCT; group 4: 2 ml lidocaine 2 %, Propofol-MCT/LCT). Assessment of pain on injection was performed after 30 % of the induction dose was given. RESULTS: Pain on injection caused by Propofol-LCT with pre-treatment of lidocaine and Propofol-MCT/LCT alone is shown to be equivalent. Comparison of Propofol-MCT/LCT with pre-treatment of lidocaine and Propofol-LCT alone shows a statistical noticeable p-value of 0.035. Propofol-MCT/LCT with pre-treatment of lidocaine suggests a tendency of causing less pain compared to Propofol-MCT/LCT. Analysis of the postoperative questionnaire supplies no significant difference. CONCLUSION: The results suggest that pain on injection is reduced equivalent using either Propofol-MCT/LCT alone or Propofol-LCT with pre-treatment of lidocaine. Pre-treatment with lidocaine before Propofol-MCT/LCT seems to have an additional effect.

Adult↗
PubMed2004

Anesthetic considerations in patients with chronic pulmonary diseases.

AIM: Increasing age and co-morbidities of patients admitted for surgery impose new challenges on the anesthesiologist. METHODS: Review of current literature regarding the perioperative management of patients with chronic pulmonary disease. RESULTS: If patients are treated adequately, surgery can be safely performed under regional and general anaesthesia. Major risk factors include type of surgery, type and duration of anesthesia, general health status and smoking history, but not certain lung function parameters. Regional anesthesia remains the first choice for intra- and postoperative care, and if general anesthesia is necessary, early extubation should be achieved. Non-invasive ventilation could be a possible alternative in weaning failure. CONCLUSION: Assessing the functional status of patients admitted to surgery remains a difficult task, and in patients identified at risk by clinical examination additional spirometry and blood gases may be helpful. If there are signs of respiratory failure, the anaesthetist should monitor the patient closely and invasively, yet there is no reason to deny any patient a substantially beneficial operation.

Anesthesia↗
PubMed2003

[Evidence-based medicine of the acute respiratory distress syndrome].

Different therapeutic approaches have recently been developed for treatment of acute respiratory distress syndrome (ARDS) with the aim of improving the outcome. The clinical significance and success of these therapies is variable with respect to evidence based medicine. Lung protective ventilation is accepted as a proven therapy and the use of positive end-expiratory pressure as well as spontaneous breathing during controlled ventilation are common therapies. High frequency ventilation, partial liquid ventilation and pulmonary surfactant application are still in the experimental stage. The prone position is recommended for severe cases of ARDS and the application of inhaled nitric oxide and of extracorporeal membrane oxygenation is established in specialized centers for patients with imminent hypoxia. But for the routine use of these three therapies a clear improvement in outcome could not demonstrated. Recommended drug therapy is limited to the administration of stress doses of corticosteroids and a special anti-inflammatory enteral diet.

Evidence-Based Medicine↗
PubMed2003

[Proportional assist ventilation combined with automatic tube compensation. A promising concept of augmented spontaneous breathing?].

The combination of proportional assist ventilation (PAV) and automatic tube compensation (ATC) is a promising concept for partial ventilatory support. In contrast to conventional pressure support ventilation (PSV), PAV+ATC provides dynamic pressure support depending on the patient's initial inspiratory effort. PAV+ATC should selectively unload the respiratory muscles from the additional workload imposed by increased respiratory system resistance and elastance as well as by endotracheal tube resistance. Patients have the ability to modify the tidal volume in response to changes in ventilatory demand, thereby improving patient-ventilator interaction and breathing comfort when compared with PSV. However, since routine measurements of respiratory mechanics during augmented spontaneous breathing are currently unavailable but would be necessary for setting the support level as a function of respiratory system mechanics during PAV, this mode cannot yet be generally recommended for routine clinical use.

Air Pressure↗
PubMed2003

[Hyperpyrexia and rhabdomyolysis after ecstasy (MDMA) intoxication].

Abuse of 3,4-methylenedioxymethamphetamine (MDMA,Ecstasy) is still growing over the last years and reports of severe or even fatal complications, such as arrhythmias, hyperpyrexia, rhabdomyolysis, disseminated intravascular coagulopathy (DIC), acute renal or liver failure or brain oedema are also increasing. We report the case of a 21-year-old male who took a suicidal overdose of MDMA and subsequently developed severe hyperpyrexia (>43 degrees C/109.4 degrees F), rhabdomyolysis with an initial myoglobin level of 88,000 microg/l, disseminated intravascular coagulation (DIC) and beginning renal and liver failure. Infusing dantrolene 140 mg (2.5 mg/kg body weight) i.v. and using supportive cooling was effective in treating hyperpyrexia. To support renal function and diuresis we increased the intravenous fluid supply up to 5 l per day which led to a raised elimination of myoglobin, urea nitrogen and creatinine within 1 week. Hemodialysis was not necessary. DIC was treated according to laboratory parameters by supply of antithrombin (AT) III, fresh frozen plasma, prothrombin complex concentrates (PPSB) and continuous aprotinin 100,000 IE/h.

Acute Kidney Injury↗
PubMed2003

Breathing pattern and workload during automatic tube compensation, pressure support and T-piece trials in weaning patients.

BACKGROUND AND OBJECTIVE: Automatic tube compensation has been designed as a new ventilatory mode to compensate for the non-linear resistance of the endotracheal tube. The study investigated the effects of automatic tube compensation compared with breathing through a T-piece or pressure support during a trial of spontaneous breathing used for weaning patients from mechanical ventilation of the lungs. METHODS: Twelve patients were studied who were ready for weaning after prolonged mechanical ventilation (10.2 +/- 8.4 days) due to acute respiratory failure. Patients with chronic obstructive pulmonary disease were excluded. Thirty minutes of automatic tube compensation were compared with 30 min periods of 7 cmH2O pressure support and T-piece breathing. Breathing patterns and workload indices were measured at the end of each study period. RESULTS: During T-piece breathing, the peak inspiratory flow rate (0.65 +/- 0.20 L s(-1)) and minute ventilation (8.9 +/- 2.7L min(-1)) were lower than during either pressure support (peak inspiratory flow rate 0.81 +/- 0.25 L s(-1) minute ventilation 10.2 +/- 2.3 L min(-1), respectively) or automatic tube compensation (peak inspiratory flow rate 0.75 +/- 0.26L s(-1); minute ventilation 10.8 +/- 2.7 L min(-1)). The pressure-time product as well as patients' work of breathing were comparable during automatic tube compensation (pressure-time product 214.5 +/- 104.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)) and T-piece breathing (pressure-time product 208.3 +/- 121.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)), whereas pressure support resulted in a significant decrease in workload indices (pressure-time product 121.2 +/- 64.1 cmH2O s(-1) min(-1), patient work of breathing 0.7 +/- 0.4 J L(-1)). CONCLUSIONS: In weaning from mechanical lung ventilation, patients' work of breathing during spontaneous breathing trials is clearly reduced by the application of pressure support 7 cmH2O, whereas the workload during automatic tube compensation corresponded closely to the values during trials of breathing through a T-piece.

Adult↗
PubMed2003

Replacement of physiologically autoinhaled nitric oxide in intubated patients.

Autoinhaled nitric oxide (NO) is produced mainly in the upper airways. Orotracheal intubation disrupts the natural autoinhalation of NO from the naso- and oropharynx. The effect of disrupting and then replacing autoinhaled NO on arterial oxygenation was investigated in intubated patients. Two groups of nine patients without lung disease were examined during anaesthesia using an inspired oxygen fraction of 0.50. In both groups, the individually produced NO of the whole respiratory tract and the upper airways was determined. The amount of NO normally autoinhaled from the upper airways was replaced for 5 min after orotracheal intubation in one group. The amount of NO from the upper respiratory tract was 47+/-19 parts per billion (ppb) in the test group and the replaced NO concentration was 48+/-20 ppb. No significant increase in arterial oxygen tension could be detected during the replacement of the autoinhaled NO. Haemodynamic parameters remained unchanged. In the control group, the NO from the upper airways was 34+/-16 ppb. In contrast to the test group, it was not replaced after intubation. These findings suggest that in healthy subjects the autoinhalation of nitric oxide does not play an important role in arterial oxygenation during anaesthesia.

Aged↗
PubMed2002

Increased airway resistance during xenon anaesthesia in pigs is attributed to physical properties of the gas.

BACKGROUND: In this study we investigated the effects of the physical properties of xenon on respiratory mechanisms in pigs. METHODS: With institutional approval, 10 female pigs (mean 25.2 (SD 2.5) kg) were anaesthetized with thiopental, remifentanil, and pancuronium. Gas flow and pressure were recorded continuously at the proximal end of the tracheal tube during constant flow ventilation for control, with 100% oxygen (control), followed by 1.5% isoflurane in 70/30% nitrogen/oxygen, 1.0% isoflurane in 70/30% nitrous oxide/oxygen, and 70/30% xenon/oxygen in random order. Compliance (C) and resistance (R) were calculated using a single compartment model. Resistance was corrected for gas viscosities eta and also for densities pho and viscosities eta as (pho*eta)(1/2) to compare assumptions of laminar and mixed flow in the airways. RESULTS: With constant flow ventilation, xenon increases inspiratory pressure compared with other gas mixtures. There were no significant differences in resistance, corrected for laminar or mixed flow, between the gas mixtures. Xenon anaesthesia did not affect compliance. CONCLUSIONS: The increase in airway pressure observed with xenon anaesthesia is attributed completely to its higher density and viscosity. Therefore, determination of airway resistance must take into account the physical properties of the gas. Xenon does not exert any major effect on airway diameter.

Airway Resistance↗
PubMed2001

Effects of combined high-dose partial liquid ventilation and almitrine on pulmonary gas exchange and hemodynamics in an animal model of acute lung injury.

OBJECTIVES: To determine possible additive effects of combined high-dose partial liquid ventilation (PLV) and almitrine bismesylate (ALM) on pulmonary gas exchange and hemodynamics in an animal model of acute lung injury (ALI). DESIGN AND SETTING: Prospective, controlled animal study in an animal research facility of a university hospital. INTERVENTIONS: ALI was induced in 12 anesthetized and mechanically ventilated pigs by repeated wash-out of surfactant. After initiation of PLV with 30 ml/kg perfluorocarbon the animals were randomly assigned to receive either accumulating doses of ALM (0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 micrograms/kg per minute) for 30 min each (n = 6) or the solvent malic acid (n = 6). MEASUREMENT AND RESULTS: Pulmonary gas exchange and hemodynamics were measured at the end of each infusion period. Compared to ALI, PLV alone significantly increased arterial oxygen partial pressure (PaO2) and decreased venous admixture (QVA/QT) and mean pulmonary artery pressure (MPAP). Administration of ALM did not result in a further improvement in PaO2, QVA/QT or MPAP compared to PLV alone but decreased PaO2 and increased QVA/QT and MPAP when 16 micrograms/kg per min ALM was compared to PLV alone. CONCLUSIONS: In an animal model of surfactant depletion induced ALI the combined treatment of PLV and ALM induced no significant improvement in pulmonary gas exchange or hemodynamics when compared to PLV alone. Moreover, high-dose ALM significantly impaired gas exchange and pulmonary hemodynamics.

Almitrine↗
PubMed2001

Effect of inhaled prostacyclin in combination with almitrine on ventilation-perfusion distributions in experimental lung injury.

BACKGROUND: Inhaled prostacyclin and intravenous almitrine have both been shown to improve pulmonary gas exchange in acute lung injury (ALI). This study was performed to investigate a possible additive effect of prostacyclin and almitrine on pulmonary ventilation-perfusion (VA/Q) ratio in ALI compared with inhaled prostacyclin or intravenous almitrine alone. METHODS: Experimental ALI was established in 24 pigs by repeated lung lavage. Animals were randomly assigned to receive either 25 ng.kg(-1).min(-1) inhaled prostacyclin alone, 1 microg.kg(-1).min(-1) almitrine alone, 25 ng.kg(-1).min(-1) inhaled prostacyclin in combination with 1 microg.kg(-1).min(-1) almitrine, or no specific treatment (controls) for 30 min. For each intervention, pulmonary gas exchange and hemodynamics were analyzed and VA/Q distributions were calculated using the multiple inert gas elimination technique. The data was analyzed within and between the groups by analysis of variance for repeated measurements, followed by the Student-Newman-Keuls test for multiple comparison when analysis of variance revealed significant differences. RESULTS: All values are expressed as mean +/- SD. In controls, pulmonary gas exchange, hemodynamics, and VA/Q distribution remained unchanged. With prostacyclin alone and almitrine alone, arterial oxygen partial pressure (PaO2) increased, whereas intrapulmonary shunt (QS/QT) decreased (P < 0.05). Combined prostacyclin and almitrine also increased PaO2 and decreased QS/QT (P < 0.05). When compared with either prostacyclin or almitrine alone, the combined application of both drugs revealed no additional effect in gas exchange or VA/Q distribution. CONCLUSIONS: The authors conclude that, in this experimental model of ALI, the combination of 25 ng.kg(-1).min(-1) prostacyclin and 1 microg.kg(-1).min(-1) almitrine does not result in an additive improvement of pulmonary gas exchange or VA/Q distribution when compared with prostacyclin or almitrine alone.

Almitrine↗
PubMed2000

Time-dependency of improvements in arterial oxygenation during partial liquid ventilation in experimental acute respiratory distress syndrome.

BACKGROUND: The mechanisms by which partial liquid ventilation (PLV) can improve gas exchange in acute lung injury are still unclear. Therefore, we examined the time- and dose-dependency of the improvements in arterial oxygen tension (PaO2) due to PLV in eight pigs with experimental lung injury, in order to discriminate increases due to oxygen dissolved in perfluorocarbon before its intrapulmonary instillation from a persistent diffusion of the respiratory gas through the liquid column. RESULTS: Application of four sequential doses of perfluorocarbon resulted in a dose-dependent increase in PaO2. Comparison of measurements 5 and 30 min after instillation of each dose revealed a time-dependent decrease in PaO2 for doses that approximated the functional residual capacity of the animals. CONCLUSION: Although oxygen dissolved in perfluorocarbon at the onset of PLV can cause a short-term improvement in arterial oxygenation, diffusion of oxygen through the liquid may not be sufficient to maintain the initially observed increase in PaO2.

Analysis of Variance↗
PubMed2000

Effect of inhaled nitric oxide in combination with almitrine on ventilation-perfusion distributions in experimental lung injury.

OBJECTIVE: To investigate a possible additive effect of combined nitric oxide (NO) and almitrine bismesylate (ALM) on pulmonary ventilation-perfusion (V(A)/Q) ratio. DESIGN: Prospective, controlled animal study. SETTING: Animal research facility of a university hospital. INTERVENTIONS: Three conditions were studied in ten female pigs with experimental acute lung injury (ALI) induced by repeated lung lavage: 1) 10 ppm NO, 2) 10 ppm NO with 1 microg/kg per min ALM, 3) 1 microg/ kg per min ALM. For each condition, gas exchange, hemodynamics and V(A)/Q distributions were analyzed using the multiple inert gas elimination technique (MIGET). MEASUREMENT AND RESULTS: With NO + ALM, arterial oxygen partial pressure (PaO2) increased from 63 +/- 18 mmHg to 202 +/- 97 mmHg while intrapulmonary shunt decreased from 50 +/- 15 % to 26 +/- 12% and blood flow to regions with a normal V(A)/Q ratio increased from 49 +/- 16 % to 72 +/- 15 %. These changes were significant when compared to untreated ALI (p < 0.05) and NO or ALM alone (p < 0.05), although improvements due to NO or ALM also reached statistical significance compared to ALI values (p < 0.05). CONCLUSIONS: We conclude that NO + ALM results in an additive improvement of pulmonary gas exchange in an experimental model of ALI by diverting additional blood flow from non-ventilated lung regions towards those with normal V(A)/Q relationships.

Administration, Inhalation↗
PubMed2000

Nasal, pulmonary and autoinhaled nitric oxide at rest and during moderate exercise.

OBJECTIVE: To investigate nasal nitric oxide (NO) excretion, pulmonary NO excretion, and autoinhalation of nasally released NO at rest compared with that during moderate exercise in smokers and non-smokers. DESIGN: Prospective observational study. SETTING: University laboratory. PARTICIPANTS: Fourteen healthy adult volunteers. INTERVENTIONS: Breathing of NO-purified air supplied via a tube system at rest and during a bicycle-ergometer workload of 60 Watt over a time of 10 min. MEASUREMENT AND RESULTS: We examined nasal and pulmonary NO excretion in smoking (n = 7) and non-smoking (n = 7) adult human volunteers. At rest, we measured constant nasal NO excretion rates of 311 +/- 89 nl/min for non-smokers and 261 +/- 142 nl/min for smokers (mean +/- SD, n.s.). During 60 W exercise, nasal NO release remained unchanged, while pulmonary NO excretion doubled compared with the rates at rest (non-smokers: 40 +/- 21 nl/min versus 23 +/- 14 nl/min, p < 0.05; smokers: 41 +/- 8 nl/min versus 22 +/- 8 nl/min, p < 0.05). The differences between smokers and non-smokers in nasal or pulmonary NO excretion were not significant. To determine the autoinhaled amount of nasally released NO, we also measured the NO concentration within the nasopharynx of five volunteers during nasal breathing. The average inhaled NO concentration was 17.8 +/- 3.1 ppb at rest and this decreased to 9.3 +/- 1.8 ppb during exercise of 60 W, while minute ventilation approximately doubled from 9 +/- 2 to 21 +/- 3 l/min. CONCLUSION: Our results demonstrate that moderate exercise increased exclusively pulmonary NO excretion. Nasal NO release, which is 10 times higher at rest, was not changed. The decrease in autoinhaled NO concentration during exercise results from dilution of the continuous nasal release by the increased respiratory gas flow. The individual NO release allows no conclusion about smoking habits.

Adult↗