Helge Opdahl - Academia.edu (original) (raw)

Papers by Helge Opdahl

$Research paper thumbnail of Intramedullary nailing of femoral shaft fractures in polytraumatized patients. a longitudinal, prospective and observational study of the procedure-related impact on cardiopulmonary- and inflammatory responses$

Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 2012

BackgroundEarly intramedullary nailing (IMN) of long bone fractures in severely injured patients ... more BackgroundEarly intramedullary nailing (IMN) of long bone fractures in severely injured patients has been evaluated as beneficial, but has also been associated with increased inflammation, multi organ failure (MOF) and morbidity. This study was initiated to evaluate the impact of primary femoral IMN on coagulation-, fibrinolysis-, inflammatory- and cardiopulmonary responses in polytraumatized patients.MethodsTwelve adult polytraumatized patients with femoral shaft fractures were included. Serial blood samples were collected to evaluate coagulation-, fibrinolytic-, and cytokine activation in arterial blood. A flow-directed pulmonary artery (PA) catheter was inserted prior to IMN. Cardiopulmonary function parameters were recorded peri- and postoperatively. The clinical course of the patients and complications were monitored and recorded daily.ResultsMean Injury Severity Score (ISS) was 31 ± 2.6. No procedure-related effect of the primary IMN on coagulation- and fibrinolysis activation...

Tidsskrift for Den norske legeforening

Acute poisoning caused by inhalation of carbon monoxide and other toxic substances is the primary... more Acute poisoning caused by inhalation of carbon monoxide and other toxic substances is the primary cause of death in fires and may occur without signs of external injury. Life-threatening symptoms may arise immediately, as in cyanide poisoning, or over a longer period, as in carbon monoxide poisoning. Severe inhalation injury may also occur independently of systemic poisoning and should always be suspected in patients with soot on their face and in the respiratory tract, or hoarseness and wheezing.

BMJ Open Respiratory Research, 2017

Introduction Removal of pulmonary secretions in mechanically ventilated patients usually requires... more Introduction Removal of pulmonary secretions in mechanically ventilated patients usually requires suction with closed catheter systems or flexible bronchoscopes. Manual ventilation is occasionally performed during such procedures if clinicians suspect inadequate ventilation. Suctioning can also be performed with the ventilator entirely disconnected from the endotracheal tube (ETT). The aim of this study was to investigate if these two procedures generate negative airway pressures, which may contribute to atelectasis. Methods The effects of device insertion and suctioning in ETTs were examined in a mechanical lung model with a pressure transducer inserted distal to ETTs of 9 mm, 8 mm and 7 mm internal diameter (ID). A 16 Fr bronchoscope and 12, 14 and 16 Fr suction catheters were used at two different vacuum levels during manual ventilation and with the ETTs disconnected. Results During manual ventilation with ETTs of 9 mm, 8 mm and 7 mm ID, and bronchoscopic suctioning at moderate suction level, peak pressure (P PEAK) dropped from 23, 22 and 24.5 cm H 2 O to 16, 16 and 15 cm H 2 O, respectively. Maximum suction reduced P PEAK to 20, 17 and 11 cm H 2 O, respectively, and the end-expiratory pressure fell from 5, 5.5 and 4.5 cm H 2 O to-2,-6 and-17 cm H 2 O. Suctioning through disconnected ETTs (open suction procedure) gave negative model airway pressures throughout the duration of the procedures. Conclusions Manual ventilation and open suction procedures induce negative end-expiratory pressure during endotracheal suctioning, which may have clinical implications in patients who need high PEEP (positive end-expiratory pressure).

BMC Anesthesiology, 2015

Background: The insertion of suction devices through endotracheal tubes (ETTs) increases airway r... more Background: The insertion of suction devices through endotracheal tubes (ETTs) increases airway resistance and the subsequent suctioning may reduce airway pressures and facilitate atelectasis. The aim of this study was to investigate how airway pressures and tidal volumes change when different combinations of suction equipment and ETT sizes are used, and to what extent unfavorable effects can be ameliorated by choice of ventilator settings. Methods: A mechanical ventilator was connected to a lung model by ETTs of 9 mm, 8 mm or 7 mm internal diameter (ID) with a pressure transducer inserted distal to the ETT. The effects of suction procedures with bronchoscope and closed catheter systems were investigated during pressure controlled ventilation (PCV) and volume controlled ventilation (VCV). In each mode, the effects of changes in inspiration:expiration (I:E) ratio, trigger sensitivity and suction pressure were examined. Results: The variables that contributed most to negative model airway pressures and loss of tidal volume during suctioning were (in descending order); 1) Small-size ETTs (7-8 mm ID) combined with large diameter suction devices (14-16 Fr); 2) inverse I:E ratio ventilation (in VCV); 3) negative ventilator trigger sensitivity; and 4) strong suction pressure. The pressure changes observed distal to the ETTs were not identical to those detected by the ventilator. Conclusions: Negative model airway pressure was induced by suctioning through small-size ETTs. The most extreme pressure and volume changes were ameliorated when conventional ventilator settings were used, such as PCV mode with short inspiration time and a trigger function sensitive to flow changes.

Anaesthesia and intensive care, 2011

Bronchoscope insertion through an endotracheal tube increases airflow resistance. Constant tidal ... more Bronchoscope insertion through an endotracheal tube increases airflow resistance. Constant tidal volume (T(v)) ventilation can be maintained by augmenting the inspiratory pressure, but increased outflow resistance cannot be compensated for. Air trapping distal to the tube may lead to higher airway pressures in volume controlled (VC) mode and reduced T(v) in pressure controlled (PC) mode. Increased end-expiratory airway pressures will not be detected by ventilator pressure sensors. In mechanically ventilated and sedated patients, the effects of bronchoscope insertion on intrabronchial pressures were recorded by a pressure transducer distal to the endoscope. In half of the patients, the ventilator was set in VC mode prior to bronchoscope insertion, keeping the previous T(v) constant. In the other half the ventilator was set in PC mode, keeping previous peak inspiratory pressures constant. All patients underwent sequences of VC-PC-VC or PC-VC-PC ventilation with two-minute intervals be...

UNLABELLED Generation of reactive oxygen intermediates by activated polymorphonuclear neutrophil ... more UNLABELLED Generation of reactive oxygen intermediates by activated polymorphonuclear neutrophil granulocytes plays an important role in development of microcirculatory injury. The effect of the beta 2-adrenergic receptor agonists (beta 2-agonists) isoprenaline and terbutaline on the chemiluminescence or oxygen consumption of human granulocytes in response to activation with n-formyl-methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA) was examined. The beta 2-agonist effect on activated cell aggregation and volume change was examined as well. As E. Coli lipopolysaccharide and FMLP may prime granulocytes for enhanced generation of reactive oxygen intermediates in response to other activators, the effect of beta 2-agonists on the priming effect of these agents was also investigated. RESULTS 1) Optimal concentrations of beta 2-agonists decrease the human granulocyte generation of reactive oxygen intermediates in response to activation with FMLP by 40-60%, without affecting the response to PMA. 2) beta 2-Agonists modify the priming effect of FMLP on activation with PMA, but do not interfere with the priming effect of E. Coli lipopolysaccharide on activation with FMLP. 3) Isoprenaline have different effects on generation of reactive oxygen intermediates and cell aggregation in FMLP-activated granulocytes. 4) High concentrations of isoprenaline and terbutaline have contrasting non-specific effects on the chemiluminescence, but not on the oxygen consumption, of activated granulocytes.

Tidsskrift for Den norske legeforening, 2010

Tidsskrift for Den norske legeforening, 2012

The Journal of Trauma: Injury, Infection, and Critical Care, 2010

Intramedullary reaming and nailing increases intramedullary pressure. This may cause intravasatio... more Intramedullary reaming and nailing increases intramedullary pressure. This may cause intravasation of bone marrow contents, leading to bone marrow embolization and altered cardiopulmonary function. Possible beneficial effects of attenuation of the intramedullary pressure increase by the use of a reamer-irrigator-aspirator (RIA) system were studied with the hypothesis that the RIA technique would cause lower numbers of pulmonary embolisms (PEs) and lesser cardiopulmonary affection than traditional reaming (TR). Intramedullary reaming and nailing was performed in intact femora of young Norwegian landrace pigs using either a standard intramedullary nailing technique (n = 8) or a RIA technique (n = 7). The hemodynamic and pulmonary effects were investigated during the reaming and nailing procedure and for 2 hours postoperatively. The animals were killed after 72 hours, and the lung/carcass weight ratio and the numbers of PEs were investigated. The pattern of the procedure-related hemodynamic and pulmonary effects did not differ significantly between the RIA and the TR groups. The RIA group had lower numbers (ns) of embolisms per square centimeter lung area than the TR group. After reaming with the TR device, two animals died of PEs, the first postoperative day. The patients with femoral shaft fracture and additional cardiopulmonary injury or preexisting reduced cardiopulmonary function, however, need special attention, and the use of RIA may, in these cases, represent a better operative alternative with a lesser operative burden.

Injury, 2011

Operations in trauma patients represent a second insult and the extent of the surgical procedures... more Operations in trauma patients represent a second insult and the extent of the surgical procedures influences the magnitude of the inflammatory response. Our hypothesis was that a reamer-irrigator-aspirator (RIA) system would cause a lesser inflammatory response than traditional reaming (TR). Coagulation, fibrinolysis and cytokine responses were studied in Norwegian landrace pigs during and after intramedullary nailing (IMN) with two different reaming systems using ELISA and chromogenic peptide substrate assays. The TR (n=8) and the RIA (n=7) reaming systems were compared to a control group (n=7). The animals were followed for 72 h. Arterial, mixed venous and femoral vein blood were withdrawn simultaneously peroperatively and until 2 h after the nail was inserted for demonstration of local, pulmonary and systemic activation of the cascade systems. At 6 h, 24 h, 48 h and 72 h postoperatively arterial blood samples were withdrawn. Significantly procedure-related increased levels were found for thrombin-antithrombin (TAT) and tissue plasminogen activator (t-PA) in the TR group and TAT in the RIA group. The local and the pulmonary activation of coagulation and fibrinolysis were more pronounced in the TR than in the RIA group, the difference reached significance for plasminogen activator inhibitor-1 (PAI-1) (arterial blood). The cytokine response, mainly represented by IL-6 increase, was more pronounced in the TR than the RIA group, and was significant for IL-6 in femoral vein blood. The arterial levels of IL-6 exceeded the mixed venous levels indicating an additional pulmonary activation of IL-6. Two animals in the TR group, who died of pulmonary embolism (PE) prior to planned study end point, had a more pronounced response compared to the rest of the TR group. A procedure-related coagulation and fibrinolytic response was demonstrated in both reaming groups, with more pronounced response in the TR than in the RIA group. Elevated levels of cytokines were demonstrated related to reaming and nailing, with significantly higher IL-6 levels in the TR than in the RIA group.

Injury, 2010

Introduction: Intramedullary orthopaedic procedures may increase the intramedullary pressure (IMP... more Introduction: Intramedullary orthopaedic procedures may increase the intramedullary pressure (IMP) and thereby cause intravasation of bone marrow contents. In recent studies by the authors the reamer-irrigator-aspirator (RIA) has been demonstrated to reduce IMP and coagulation-, fibrinolysis-and cytokine responses, but did not prove any significant difference in cardiopulmonary function parameters or numbers of emboli when compared to a traditional reaming (TR) system. The correlations between IMP increase, regardless type of reamer, and inflammatory-and coagulation responses, pulmonary embolization, and cardiopulmonary alterations have, however, not previously been analyzed in this material. Our hypothesis was that a lower IMP would result in reduced occurrence of pulmonary embolization, reduced inflammatoryand coagulation responses, as well as reduced cardiopulmonary alterations. Materials and Methods: Twenty-eight young Norwegian landrace pigs were exposed to femoral intramedullary reaming, with either the TR (n = 10) or the RIA (n = 10) system, or used as controls (n = 8). IMP was recorded during reaming and nailing. Serial blood samples for demonstration of coagulation-, fibrinolysis-, and cytokine activation were withdrawn peroperatively and until 72 hours post nail insertion. Circulatory and pulmonary effects were monitored peroperatively and until two hours postoperatively. The animals were sacrificed 72 hours post nail insertion and lung tissue biopsies were harvested and examined for lung emboli. Results and Conclusions: A strong correlation between increased IMP and increased coagulationand cytokine responses was found. The number of emboli was not significantly correlated to IMP, but was strongly correlated to changes in the coagulation-and cytokine responses. No clinical relevant correlations were observed between increased IMP or numbers of lung emboli and changes in hemodynamic-or pulmonary function parameters. A correlation between coagulation activation and cytokine activation was observed. This study confirms the connection between increased IMP, increased coagulation activation and the magnitude of pulmonary emboli in a model evaluating the effects of intramedullary reaming of intact pig femora. In this model, the lowering of IMP during reaming, as obtained with RIA, reduced the magnitude of and the effects of bone marrow extravasation.

Inflammation, 1993

Polymorphonuclear neutrophil granulocytes (PMN) may contribute to the lung injury induced by nonp... more Polymorphonuclear neutrophil granulocytes (PMN) may contribute to the lung injury induced by nonpulmonary infections with gram-negative bacteria. The direct effect of E. coli lipopolysaccharide (LPS) on isolated human PMN or mixed leukocytes (ML), as well as the priming effect of preincubating cells with LPS, was examined in assays measuring the maximal rate of oxygen consumption (OC), cell chemiluminescence (CHML), and aggregation (AGG). LPS, 1-10 micrograms/ml, caused no acute response in PMN or ML suspended in Fisher's-HEPES medium with BSA (FHA), but increased both CHML and AGG of cells suspended in autologous plasma. Preincubation in FHA with LPS, 1 microgram/ml, for more than 15 min increased the OC of PMN activated with zymosan-activated plasma (ZAP) or n-formyl-methionyl-leu-cyl-phenylalanine (FMLP) by more than 100%. A similar increase in the CHML of such cells was seen after FMLP, but not after ZAP. ZAP, however, primed the CHML response of the cells to subsequent activation with FMLP more than did preincubation with LPS. Previous exposure to both agents had an additive effect. Preincubation of PMN with LPS decreased the time interval from addition of phorbol myristate acetate (PMA) to peak OC response, but less so than previous activation with FMLP. Neither agent affected the maximal rate of OC after addition of PMA. LPS also increased the PMN aggregation induced by ZAP and FMLP, but not by PMA. Cells preincubated with LPS, 0.01 microgram/ml, increased their CHML in response to FMLP if suspended in Krebs-Ringer balanced salt solution, but not if suspended in FHA. Such preincubation had no effect on OC of similarly activated cells in any of the media.

Critical Care Medicine, 1997

To determine the oxyhemoglobin dissociation curve in blood with pH of approximately 6.3 due to me... more To determine the oxyhemoglobin dissociation curve in blood with pH of approximately 6.3 due to metabolic and superimposed respiratory acidosis, and to evaluate the oxygen delivery capacity of the blood under these circumstances. In vitro study. A blood gas laboratory in a university institute for respiratory physiology. Heparinized normal human blood. The oxyhemoglobin dissociation curve was determined by measuring PO2, pH, PCO2, and hemoglobin oxygen saturation at 37 degrees C in mixtures of blood from two reservoirs, both prepared by titration with lactic acid to a pH of 6.3 during tonometry with gases containing 4.2% CO2 and high and low oxygen percentages, respectively. For determination of the effect of additional increases in PCO2, the reservoir blood thus produced was prepared by further tonometry with gases containing 12.8% CO2 and the same oxygen percentages. With the same degree of lactic acidosis (blood lactate concentration of 52 mmol/L), the position of the oxyhemoglobin dissociation curve was the same for blood with PCO2 of 30 torr (4 kPa) and pH of 6.295 and for blood with PCO2 of 90 torr (12 kPa) and pH of 6.165. During tonometry with a gas with PCO2 of 30 torr (4 kPa) and PO2 of 20 torr (2.7 kPa) and addition of increasing amounts of lactic acid, leading to a stepwise change in pH from 6.7 to 6.0, hemoglobin oxygen saturation decreased with decreasing pH from 6.7 to 6.4, but remained the same at a pH of between 6.4 and 6.0. The measured rightward shift of the oxyhemoglobin dissociation curve at such a low pH was clearly less pronounced than that calculated using commonly applied equations, in particular, at the lowest pH. The beneficial effects of the rightward shift of the oxyhemoglobin dissociation curve on the estimates of extractable oxygen at a given venous PO2 decrease with decreasing pH, and disappear rapidly when the Pao2 is reduced below normal. The acidemia-induced rightward shift of the oxyhemoglobin dissociation curve does not increase further at a pH < 6.4, and is, at such extreme acidemia, less pronounced than calculated by the commonly used equations. To obtain optimal tissue oxygenation in patients with severe circulatory failure and extreme metabolic acidosis, Pao2 should be > 250 torr (> 33.3 kPa).

Critical Care, 2009

Quality assurance report on the use of continuous positive airway pressure and end-tidal carbon d... more Quality assurance report on the use of continuous positive airway pressure and end-tidal carbon dioxide during respiratory distress in field emergency care D Lain, S Bourn P7 Cardiogenic oscillations extracted from spontaneous breathing airway pressure and flow signal are related to chest wall motility and continuous positive airway pressure

$Research paper thumbnail of Intramedullary nailing of femoral shaft fractures. Part II: Fracture-healing with static interlocking fixation$

The Journal of Bone and …, 1988

The PDF of the article you requested follows this cover page. This is an enhanced PDF from The Jo... more The PDF of the article you requested follows this cover page. This is an enhanced PDF from The Journal of Bone and Joint Surgery ... 1988;70:1453-1462. J Bone Joint Surg Am. RJ Brumback, S Uwagie-Ero, RP Lakatos, A Poka, GH Bathon and AR Burgess

Acta Physiologica Scandinavica, 1985

Acta Anaesthesiologica Scandinavica, 2005

We describe an unusual case of acute myocardial infarction (AMI) and cardiogenic shock in a 25-ye... more We describe an unusual case of acute myocardial infarction (AMI) and cardiogenic shock in a 25-year-old woman. After coronary revascularization, a thyrotoxic storm developed and the patient's cardiac failure changed into a hyperdynamic circulation without obvious changes in the patient's vital signs. This report will focus on three issues: (1) the benefit of advanced hemodynamic monitoring in circulatory unstable patients, (2) the confounding effects of untreated hyperthyroidism on the circulation, and (3) previous cancer treatment as a cause of AMI in young persons.

Acta Anaesthesiologica Scandinavica, 1993

E. coli LPS was infused (1 microgram/kg to 5 mg/kg over 30 min) to spontaneously breathing rabbit... more E. coli LPS was infused (1 microgram/kg to 5 mg/kg over 30 min) to spontaneously breathing rabbits, and their arterial blood pressure (ABP), blood leukocyte count and blood gases were observed for 2.5-3.5 h. Pulmonary vascular and airway function were subsequently evaluated in vitro by comparing weight changes, fluid filtration rates, pulmonary vascular resistance (PVR) and airway pressures in their isolated, blood-perfused lungs with those in lungs from untreated rabbits. Lung preparations from both groups of animals were then exposed to autologous zymosan-activated plasma (ZAP) or n-formyl-methionyl-leucyl-phenylalanine (FMLP) and perfused for 2 more hours. LPS addition to isolated rabbit leukocytes increased cell aggregation; cell chemiluminescence after activation with FMLP was also enhanced. Infusion of 1-5 mg/kg LPS decreased the count of all types of leukocytes and caused a metabolic acidosis (BE < -8 mmol), but no decrease in ABP. PAO2-Pao2 increased by about 2.0 kPa. No vascular permeability increase was detected in the lungs of these animals during subsequent in vitro perfusion. Addition of ZAP or FMLP during perfusion markedly increased the PVR in lungs from LPS animals, but did not induce major microvascular leakage. No significant differences in edema between lungs from LPS-treated and control animals were found by microscopy.

Acta Anaesthesiologica Scandinavica, 1987

The amount of reactive oxygen intermediates (ROI) generated by activated polymorphonuclear neutro... more The amount of reactive oxygen intermediates (ROI) generated by activated polymorphonuclear neutrophils (PMN), as well as the closeness of contact between PMN and vessel wall, may determine whether PMN activators will induce the adult respiratory distress syndrome. We examined the ROI-generating and aggregating effects of zymosan activated plasma (ZAP), phorbol myristate acetate (PMA) and n-formyl-methionyl-leucyl-phenylalanine (FMLP), on isolated human and rabbit PMN. PMA, after a short lag phase, induced a large and long-lasting increase in ROI generation. The initial peak response was higher and more rapid in human than in rabbit cells. The reaction to FMLP occurred almost instantaneously, but was much weaker than that to PMA, and ROI generation returned to near baseline in less than 10 min. No species difference was seen. ZAP caused an FMLP-like ROI response in human cells, whereas no response was observed in rabbit PMN. PMN aggregation was induced by all three activators, most markedly by PMA. No species difference was detected for PMA; FMLP gave a stronger aggregation of rabbit than of human PMN, however, while the opposite was true for ZAP. In conclusion, ZAP was a potent stimulus for PMN aggregation, but had modest (or no) effects on the production of ROI. Marked differences between human and rabbit PMN responses were observed.