Biomedical subjects

Jürgen Peters

Publications and source records attributed to Jürgen Peters.

At least 19 recordsLinked to original sources

PubMed2007

Extracellular proteasome in the human alveolar space: a new housekeeping enzyme?

We hypothesized that 20S proteasome is present and functional in the extracellular alveolar space in humans. Proteasomal activity was measured in bronchoalveolar lavage (BAL) supernatant from eight humans using specific proteasomal fluorogenic substrates and I(125)-albumin with and without specific proteasome inhibitors. Furthermore, gelfiltration, Western blot technique, and mass spectrometry were applied for proteasome characterization. All proteasomal fluorogenic substrates were hydrolyzed by BAL supernatant, with hydrolysis inhibited by epoxomicin (P = 0.024) and other proteasome inhibitors as well. E64, a lysosomal inhibitor, did not inhibit enzyme activity. The majority of proteolytic activity was detected in BAL supernatant rather than in the cell pellet. No correlation was found between proteasomal hydrolysis in BAL supernatant and lactate dehydrogenase activity, the total cell count in the cell pellet, and the fraction of avital cells in the cell pellet, ruling out cell lysis as a major source of proteasomal activity. Gelfiltration revealed hydrolyzing activity in the supernatant at 660 kDa and proteasome core proteins after analysis by ESI-QqTOF mass spectrometry. Furthermore, Western blots using a polyclonal antibody against proteasomal alpha-/beta-subunits detected proteasomal proteins in the typical 20- to 30-kDa range in BAL supernatant. Incubation of BAL supernatant with I(125)-albumin showed a high mean cleavage rate (101.8 microg/ml x h lavage +/- 46 SD) that was inhibited by epoxomicin (P = 0.013) and was ATP and ubiquitin independent. We identified for the first time extracellular, biologically active, ATP- and ubiquitin-independent 20S proteasome in the human alveolar space, with a high albumin cleavage rate. Possibly, the proteasome assists in maintenance of a low intra-alveolar oncotic pressure and/or alveolar protein degradation.

Aged↗

PubMed2006

A cemented caval vein filter: case report.

STUDY DESIGN: Case report. OBJECTIVE: To present a previously undescribed complication of bone cement use during spinal surgery. SUMMARY OF BACKGROUND DATA: Surgical cement reaching the circulation is a frequently described complication. The placement of caval vein filters is a routine measure in specific patients to prevent thrombotic material, usually from deep venous thrombosis in the lower extremities, from reaching the pulmonary circulation. A case of bone cement getting trapped in the caval filter rendering it unremovable has not been published. METHODS: A 66-year-old patient underwent dorsal spondylodesis of the lumbar spine for superinfected metastasis with instability. Because of deep venous thrombosis of both femoral and iliac veins, a caval filter had been placed before surgery. Bone cement from the surgical procedure migrated into the venous bloodstream and got caught in the caval filter, thus rendering the filter unremovable. RESULTS: Surgical removal of the filter was necessary. CONCLUSION: If caval filters are present in patients undergoing surgery involving the use of bone cement, the possibility of cement being caught by the filter must be considered.

Aged↗

PubMed2006

The predisposition to inspiratory upper airway collapse during partial neuromuscular blockade.

RATIONALE: Partial neuromuscular transmission failure by acetylcholine receptor blockade (neuromuscular blockade) or antibody-mediated functional loss (myasthenia gravis), even with a magnitude of muscle weakness that does not evoke respiratory symptoms, can evoke dysphagia and decreased inspiratory airflow, and increases the risk of susceptible patients to develop severe pulmonary complications. OBJECTIVES: To assess whether impaired neuromuscular transmission predisposes individuals to inspiratory upper airway collapse, we assessed supraglottic airway diameter and volume by respiratory-gated magnetic resonance imaging, upper airway dilator muscle function (genioglossus force and EMG), and changes in lung volume, respiratory timing, and peripheral muscle function before, during, and after partial neuromuscular blockade in healthy, awake volunteers. MEASUREMENTS AND MAIN RESULTS: Partial neuromuscular blockade (train-of-four [TOF] ratio: 0.5 and 0.8) was associated with the following: (1) a decrease of inspiratory retropalatal and retroglossal upper airway volume to 66 +/- 22 and 82 +/- 12% of baseline, which was significantly more intense in the retropalatal area; (2) an attenuation of the normal increase in anteroposterior upper airway diameter during forced inspiration to 74 +/- 18% of baseline; (3) a decrease in genioglossus activity during maximum voluntary tongue protrusion to 39 +/- 19% (TOF, 0.5) and 73 +/- 29% (TOF, 0.8) of baseline; and (4) no effects on upper airway size during expiration, lung volume, and respiratory timing. CONCLUSIONS: Thus, impaired neuromuscular transmission, even to a degree insufficient to evoke respiratory symptoms, markedly impairs upper airway dimensions and function. This may be explained by an impairment of the balance between upper airway dilating forces and negative intraluminal pressure generated during inspiration by respiratory "pump" muscles.

Adult↗

PubMed2006

Treatment of severe acute respiratory distress syndrome: role of extracorporeal gas exchange.

OBJECTIVE: To evaluate the effect of extracorporeal gas exchange (ECMO) on mortality of patients referred with severe acute respiratory distress syndrome (ARDS). DESIGN AND SETTING: Prospective observational study in a university hospital ICU. PATIENTS: 150 patients with severe ARDS. INTERVENTIONS: Multimodal treatment with and without ECMO. MEASUREMENTS AND MAIN RESULTS: We treated 118 patients (78.7%) conservatively and 32 patients with ECMO. Patients in the ECMO group presented with significantly more severe disease (lung injury score 3.8+/-0.3 vs. 3.3+/-0.4; SOFA score 52+/-14 vs. 43+/-12; and SAPS score 14+/-3.3 vs. 10+/-3.5). Mortality in ECMO-treated patients tended to be higher than that with conservative treatment (46.9% vs. 28.8%, p=0.059). Multivariate logistic regression analyses with backward selection excluded ECMO as predictor of mortality (p=0.79). Independent predictors of mortality were age (odds ratio 1.044, 95% confidence interval 1.014-1.075, p=0.004), mean pulmonary artery pressure (1.082, 1.026-1.141, p=0.036), sequential organ failure assessment score (1.148, 1.018-1.294, p=0.024), and days of mechanical ventilation prior to referral (1.064, 1.008-1.123, p=0.025). CONCLUSION: ECMO treatment does not predict mortality in patients with most severe ARDS.

Adult↗

PubMed2006

Size matters for the tripeptidylpeptidase II complex from Drosophila: The 6-MDa spindle form stabilizes the activated state.

Tripeptidylpeptidase II (TPP II) is an exopeptidase of the subtilisin type of serine proteases, a key component of the protein degradation cascade in many eukaryotes, which cleaves tripeptides from the N terminus of proteasome-released products. The Drosophila TPP II is a large homooligomeric complex (approximately 6 MDa) that is organized in a unique repetitive structure with two strands each composed of ten stacked homodimers; two strands intertwine to form a spindle-shaped structure. We report a novel procedure of preparing an active, structurally homogeneous TPP II holo-complex overexpressed in Escherichia coli. Assembly studies revealed that the specific activity of TPP II increases with oligomer size, which in turn is strongly concentration-dependent. At a TPP II concentration such as prevailing in Drosophila, equilibration of size and activity proceeds on a time scale of hours and leads to spindle formation at a TPP II concentration of > or =0.03 mg/ml. Before equilibrium is reached, activation lags behind assembly, suggesting that activation occurs in a two-step process consisting of (i) assembly and (ii) a subsequent conformational change leading to a switch from basal to full activity. We propose a model consistent with the hyperbolic increase of activity with oligomer size. Spindle formation by strand pairing causes both significant thermodynamic and kinetic stabilization. The strands inherently heterogeneous in length are thus locked into a discrete oligomeric state. Our data indicate that the unique spindle form of the holo-complex represents an assembly motif stabilizing a highly active state.

Aminopeptidases↗

PubMed2006

Frequency and outcomes of acute renal failure following thoracic aortic stent-graft placement.

We assessed the incidence, correlates, and outcomes of acute renal failure (ARF) after thoracic aortic stent-graft placement. Postprocedural ARF is an inherent complication of catheter-based interventional procedures that use intra-arterial contrast agents and has adverse effects on short- and long-term outcomes. However, few data exist on the incidence, predictors, and outcomes of ARF after thoracic aortic stent-graft placement. We analyzed data of 97 patients (64.4 +/- 11.6 years of age; 73% men) who underwent thoracic aortic stent-graft placement from July 1999 to October 2005. Postprocedural ARF was defined as an increase > or = 25% and/or > or = 0.5 mg/dl in preprocedural serum creatinine at 48 hours after the procedure. Baseline estimated glomerular filtration rate was 65 +/- 24 ml/min/1.73 m2. Chronic kidney disease (glomerular filtration rate < or = 60 ml/min/1.73 m2) at baseline was present in 45% of patients. During the stent-graft procedure, patients received 307 +/- 188 ml of nonionic contrast medium. Postprocedural ARF occurred in 33 patients (34%), and 3 required dialysis. Multivariable analysis identified American Society of Anesthesiologists class > 3 (odds ratio 5.53, 95% confidence interval 1.71 to 17.85, p = 0.004) and duration of the stent-graft procedure (odds ratio 1.01, 95% confidence interval 1.001 to 1.014, p = 0.022) as independent predictors of postprocedural ARF. Compared with patients without ARF, those with ARF had markedly higher 30-day (18.2 +/- 6.7% vs 1.6 +/- 1.6%, p = 0.0022) and 1-year (35.2 +/- 8.6% vs 10.1 +/- 3.9%, p = 0.001) mortality. In conclusion, postprocedural ARF is a frequent complication of thoracic aortic stent-graft placement and has a significant adverse effect on 30-day and 1-year survival. Baseline factors identified in our study as associated with increased risk of ARF may facilitate a comprehensive informed consent process by way of patient education. In addition, identification of an at-risk subset may allow modification of reversible periprocedural factors that may help decrease postprocedural ARF.

Acute Kidney Injury↗

PubMed2006

Prevalence of pulmonary hypertension associated with severe acute respiratory distress syndrome: predictive value of computed tomography.

OBJECTIVE: To evaluate the prevalence of pulmonary hypertension associated with severe acute respiratory distress syndrome (ARDS) and to asses the value of pulmonary artery trunk diameter (PAT) to predict pulmonary hypertension. DESIGN: Prospective study SETTING: University teaching hospital and ARDS referral center. PATIENTS: 103 patients with ARDS, who received both right heart catheterization and chest computed tomography. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: 95 patients (92.2%) with ARDS had pulmonary artery hypertension, 16 of them (16.8%) mild, 72 (75.8%) moderate, and 7 (7.4%) severe, as assessed by right heart catheterization. Of the patients with moderate and severe pulmonary hypertension, 43 had a pulmonary artery trunk diameter >or=29 mm yielding a sensitivity of 0.54 and a specificity of 0.63. Pulmonary artery trunk diameter correlated significantly but weakly with mean pulmonary artery pressure (r=0.34, p=0.0004). The positive predictive value was 0.83, and the negative predictive value was 0.28. The diagnosis of pulmonary hypertension by PAT diameter measurements was incorrect in 43.7% of patients with ARDS. CONCLUSIONS: Pulmonary artery hypertension has a high prevalence in patients with severe ARDS. Measurement of PAT diameter on admission CT scan is an unreliable tool for identification of ARDS patients with pulmonary hypertension.

Comorbidity↗

PubMed2006

Inter-domain orientation and motions in VAT-N explored by residual dipolar couplings and 15N backbone relaxation.

The N-terminal domain of VAT (Valosine-containing protein-like ATPase of Thermoplasma acidophilum), VAT-N (20.5 kDa), is considered to be the primary substrate-recognition site of the complex. The solution structure of VAT-N derived in our laboratory using conventionally obtained NMR restraints shows the existence of two equally sized sub-domains, VAT-Nn and VAT-Nc, together forming a kidney-shaped overall structure. The putative substrate-binding site of VAT-N involves free loops and a highly charged groove located on the surface of the protein. Alternatively, the opening of the cleft between the domains to accommodate substrate has been proposed to be part of the functional mechanism. We have used the residual dipolar couplings (RDCs) obtained in a bicelle medium to refine the structure of VAT-N. The long-range information available from RDCs both defines the sub-domain orientation and probes possible inter-domain motions. In addition, 15N backbone relaxation data were obtained and analysed within the model-free framework. Together, the data provides a refined structure with improved local geometry, but with the overall kidney shape intact. Further, the protein is rigid overall, with no evidence of inter-domain motions.

Adenosine Triphosphatases↗

PubMed2006

Endovascular stent-graft treatment of penetrating aortic ulcer: results over a median follow-up of 27 months.

BACKGROUND: Penetrating aortic ulcer (PAU) is increasingly acknowledged as a pathological variant of classic false-lumen aortic dissection with a high incidence of bleeding complications and rupture in up to 40% of patients. The objective of this study was to investigate the results of endovascular stent-graft placement for the treatment of patients with PAUs. METHODS: Between July 1999 and December 2004, endovascular stent-graft repair of PAU was performed in 22 patients (69.1 +/- 7.8 years, 16 men), 3 (14%) of whom had contained aortic rupture. Stent-graft placement was performed in the cardiac catheterization laboratory with the patient under general anesthesia, using a surgical access. RESULTS: Procedural success was achieved in all but 1 patient (technical success rate 96%). Postoperatively, 1 (5%) patient had minor stroke with transient amentia. There were no other inhospital complications or deaths. During a median follow-up of 27 (range 1-62) months, 1 patient underwent adjunctive stent-graft placement for type I endoleak. Three patients died unrelated to the aortic disease late during follow-up. Overall survival rates were 100% at 30 days, 100% at 1 year, 82.5% +/- 11.3% at 2 years, and 61.9% +/- 20.0% at 5 years. CONCLUSIONS: Endovascular stent-graft treatment is an effective treatment for patients with PAU and is associated with low procedural morbidity. Both acute and midterm mortality of this novel treatment concept appear to be favorable compared with the natural course of the disease.

Aged↗

PubMed2006

The vasopressin system: physiology and clinical strategies.

Vasopressin, synthesized in the hypothalamus, is released by increased plasma osmolality, decreased arterial pressure, and reductions in cardiac volume. Three subtypes of vasopressin receptors, V1, V2, and V3, have been identified, mediating vasoconstriction, water reabsorption, and central nervous system effects, respectively. Vasopressin and its analogs have been studied intensively for the treatment of states of "relative vasopressin deficiency," such as sepsis, vasodilatory shock, intraoperative hypotension, and cardiopulmonary resuscitation. Infusion of vasopressin (0.01-0.04 U/min) decreases catecholamine requirements in patients with sepsis and other types of vasodilatory shock. Bolus application of 1 mg terlipressin, the V1 agonist, reverses refractory hypotension in anesthetized patients and has been studied in patients with septic shock and chronic liver failure. During cardiopulmonary resuscitation, a 40-U bolus dose of vasopressin may be considered to replace the first or second bolus of epinephrine regardless of the initial rhythm. The side effects of vasopressin and its analogs must be further characterized.

Adrenocorticotropic Hormone↗

PubMed2006

Postoperative upper airway obstruction after recovery of the train of four ratio of the adductor pollicis muscle from neuromuscular blockade.

Anesthetics, and even minimal residual neuromuscular blockade, may lead to upper airway obstruction (UAO). In this study we assessed by spirometry in patients with a train-of-four (TOF) ratio >0.9 the incidence of UAO (i.e., the ratio of maximal expiratory flow and maximal inspiratory flow at 50% of vital capacity [MEF50/MIF50] >1) and determined if UAO is induced by neuromuscular blockade (defined by a forced vital capacity [FVC] fade, i.e., a decrease in values of FVC from the first to the second consecutive spirometric maneuver of > or =10%). Patients received propofol and opioids for anesthesia. Spirometry was performed by a series of 3 repetitive spirometric maneuvers: the first before induction (under midazolam premedication), the second after tracheal extubation (TOF ratio: 0.9 or more), and the third 30 min later. Immediately after tracheal extubation and 30 min later, 48 and 6 of 130 patients, respectively, were not able to perform spirometry appropriately because of sedation. The incidence of UAO increased significantly (P < 0.01) from 82 of 130 patients (63%) at preinduction baseline to 70 of 82 patients (85%) after extubation, and subsequently decreased within 30 min to values observed at baseline (80 of 124 patients, 65%). The mean maximal expiratory flow and maximal inspiratory flow at 50% of vital capacity ratio after tracheal extubation was significantly increased from baseline (by 20%; 1.39 +/- 1.01 versus 1.73 +/- 1.02; P < 0.01), and subsequently decreased significantly to values observed at baseline (1.49 +/- 0.93). A statistically significant FVC fade was not present, and a FVC fade of > or =10% was observed in only 2 patients after extubation. Thus, recovery of the TOF ratio to 0.9 predicts with high probability an absence of neuromuscular blocking drug-induced UAO, but outliers, i.e., persistent effects of neuromuscular blockade on upper airway integrity despite recovery of the TOF ratio, may still occur.

Adult↗

PubMed2005

VAT, the thermoplasma homolog of mammalian p97/VCP, is an N domain-regulated protein unfoldase.

The Thermoplasma VCP-like ATPase from Thermoplasma acidophilum (VAT) ATPase is a member of the two-domain AAA ATPases and homologous to the mammalian p97/VCP and NSF proteins. We show here that the VAT ATPase complex unfolds green fluorescent protein (GFP) labeled with the ssrA-degradation tag. Increasing the Mg2+ concentration derepresses the ATPase activity and concomitantly stimulates the unfolding activity of VAT. Similarly, the VATDeltaN complex, a mutant of VAT deleted for the N domain, displays up to 24-fold enhanced ATP hydrolysis and 250-fold enhanced GFP unfolding activity when compared with wild-type VAT. To determine the individual contribution of the two AAA domains to ATP hydrolysis and GFP unfolding we performed extensive site-directed mutagenesis of the Walker A, Walker B, sensor-1, and pore residues in both AAA domains. Analysis of the VAT mutant proteins, where ATP hydrolysis was confined to a single AAA domain, revealed that the first domain (D1) is sufficient to exert GFP unfolding indistinguishable from wild-type VAT, while the second AAA domain (D2), although active, is significantly less efficient than wild-type VAT. A single conserved aromatic residue in the D1 section of the pore was found to be essential for GFP unfolding. In contrast, two neighboring residues in the D2 section of the pore had to be exchanged simultaneously, to achieve a drastic inhibition of GFP unfolding.

Adenosine Triphosphatases↗

PubMed2005

Lethal acute respiratory distress syndrome during anti-TNF-alpha therapy for rheumatoid arthritis.

Tumor necrosis factor alpha (TNF-alpha) blocking drugs improve therapy for rheumatic diseases, but the risk of additional immunosuppression and infection is unclear. We report on a patient with rheumatoid arthritis treated with etanercept for 2 years, in addition to methotrexate and prednyliden, who developed fulminant pneumococcal pneumonia with rapid progression to fatal acute respiratory distress syndrome (ARDS) and septic shock. In patients receiving anti-TNF-alpha therapy, especially in combination with corticosteroids, signs of pulmonary infection should be regarded as very serious, as fulminant pneumonia with ARDS and severe sepsis may develop within 24 h.

Arthritis, Rheumatoid↗

PubMed2005

Molecular architecture and assembly mechanism of Drosophila tripeptidyl peptidase II.

In eukaryotes, tripeptidyl peptidase II (TPPII) is a crucial component of the proteolytic cascade acting downstream of the 26S proteasome in the ubiquitin-proteasome pathway. It is an amino peptidase belonging to the subtilase family removing tripeptides from the free N terminus of oligopeptides. The 150-kDa subunits of Drosophila TPPII assemble into a giant proteolytic complex of 6 MDa with a remarkable architecture consisting of two segmented and twisted strands that form a spindle-shaped structure. A refined 3D model has been obtained by cryoelectron microscopy, which reveals details of the molecular architecture and, in conjunction with biochemical data, provides insight into the assembly mechanism. The building blocks of this complex are apparently dimers, within which the 150-kDa monomers are oriented head to head. Stacking of these dimers leads to the formation of twisted single strands, two of which comprise the fully assembled spindle. This spindle also forms when TPPII is heterologously expressed in Escherichia coli, demonstrating that no scaffolding protein is required for complex formation and length determination. Reciprocal interactions of the N-terminal part of subunits from neighboring strands are probably involved in the formation of the native quaternary structure, lending the TPPII spindle a stability higher than that of single strands.

Aminopeptidases↗

PubMed2005

Endovascular stent-graft treatment of aortic dissection: determinants of post-interventional outcome.

AIMS: To investigate the results of endovascular stent-graft placement for the treatment of patients with type B aortic dissection (B-AD). METHODS AND RESULTS: A total of 38 patients (62+/-10 years, 32 male) with acute (n=10) and chronic (n=28) type B-AD were treated with endovascular stent-grafts. The implantation procedure was successful in all patients. Peri-procedural non-fatal complications occurred in four (11%) patients. Overall, 4/38 (11%) patients died during the in-hospital period. Patients undergoing stent-graft placement for acute AD had a significantly higher in-hospital mortality than patients with chronic AD (40 vs. 0%, P=0.001). During a median follow-up of 18 (1-57) months, there were six additional deaths. Overall survival rates were 97.4+/-2.6% at 30 days, 80.4+/-6.7% at 1 year, 73.2+/-7.8% at 2 years, and 54.9+/-16.9% at 4 years. Patients with a poor clinical health status (ASA class > 3) had a significantly reduced life expectancy compared with patients with only moderate co-morbidities (ASA class </= 3) (1-year survival rate 28.6+/-17.1 vs. 92.6+/-6.7%, P=0.0001). Multivariable analysis revealed that a poor clinical health status (ASA>3) pre-operatively (HR=29.5, 95% CI 1.5-581.9, P=0.026) and increased age (HR=1.1, 95% CI 0.9-1.2, P=0.084) were independent determinants of post-interventional mortality. CONCLUSION: Endovascular stent-graft treatment is a safe alternative for patients with AD. The pre-operative clinical health status of the patient is the most important determinant of post-interventional outcome. Careful patient selection is thus of particular importance.

Acute Disease↗

PubMed2005

Endovascular stent-graft placement for acute and contained rupture of the descending thoracic aorta.

OBJECTIVES: To identify determinants of postinterventional death after endovascular stent-graft placement for acute rupture of the descending thoracic aorta, an emerging therapeutic modality for this highly life-threatening condition. METHODS: Between July 1999 and November 2004, 17 patients (14 males; mean age, 65+/-16 (25-83) years) underwent stent-graft repair of the descending thoracic aorta for acute rupture from a thoracic aneurysm (TAA, n=6), acute aortic dissection (AAD, n=6), penetrating aortic ulcer (PAU, n=3), or blunt chest trauma (n=2). Immediate, 30-day, 1-year, and 3-year mortality was assessed. Twenty-one clinical and procedural variables were evaluated in a post-hoc analysis regarding their influence on mortality. Of these, four preprocedural factors with the greatest impact were used to construct a rupture score with a scale from 0 (no adverse prognostic factors present) to 4 (all four adverse factors present). RESULTS: Stent-graft placement was technically feasible in all patients. Complete exclusion of the ruptured aortic pathology could be achieved in only 11 (65%) patients, despite implantation of 1.6+/-0.9 stent-grafts per patient, with a median length of 130 mm. There was one procedure-related early complication (bleeding at the access site). One patient died immediately following the procedure because of progressive mediastinal hematoma, although the rupture site was effectively sealed. Overall survival rates were (76.5+/-10.3)% at 30 days and (52.9+/-12.1)% at 1 year and remained at (52.9+/-12.1)% at 3 years. The four most important preprocedural denominators of death were (1) TAA or AAD as the underlying etiology of aortic rupture (P=0.024), (2) maximum aortic diameter>5 cm (P=0.024), (3) presence of mediastinal hematoma (P=0.056), and (4) an estimated lesion length requiring >1 stent-graft to be covered (P=0.009). Furthermore, residual leakage at the conclusion of the procedure (P=0.009), postprocedural need for dialysis (P=0.004), and prolonged ventilation (P=0.043) were significantly associated with postprocedural death. Using a threshold of >or=3, the rupture score constructed on the basis of the four preprocedural denominators of death was found to be well suited to discriminate postprocedural death (1-year survival: (20.0+/-12.7)% in patients with a rupture score>or=3 vs. 100% in patients with a rupture score<3, P=0.001). CONCLUSION: Endovascular stent-graft placement in patients with acute aortic rupture was technically feasible, albeit still associated with high mortality. A simple risk score constructed in retrospect, on the basis of preprocedural prognostic factors, appeared to provide a useful separation of candidates who are likely to benefit from a straightforward endovascular procedure and should be tested prospectively in future studies.

Acute Disease↗

PubMed2005

Inspired oxygen fraction of 0.8 does not attenuate postoperative nausea and vomiting after strabismus surgery.

BACKGROUND: Postoperative nausea and vomiting (PONV) is a distressing problem after strabismus surgery. An inspired oxygen fraction has been reported to decrease PONV in patients after colon resection and to be more effective than ondansetron after gynecologic laparoscopy. Therefore, in a randomized, prospective, placebo-controlled study, the authors tested whether an inspired oxygen fraction of 0.8 decreases PONV in patients undergoing strabismus surgery and whether oxygen is more effective than ondansetron. METHODS: With approval of the authors' institutional review board, 210 patients were randomly assigned to receive one of three treatments: (1) 30% inspired oxygen in air plus intravenous administration of saline, (2) 80% inspired oxygen in air plus intravenous administration of saline, or (3) 30% inspired oxygen in air plus 75 microg/kg ondansetron intravenously during induction. General anesthesia was standardized and included etomidate, alfentanil, and mivacurium for induction and sevoflurane for maintenance. PONV was evaluated 6 and 24 h postoperatively by an investigator unaware of treatment assignment. RESULTS: Overall postoperative incidence of nausea and vomiting was 41% for inspired oxygen fraction of 0.3 plus placebo, 38% for inspired oxygen fraction of 0.8 plus placebo, and 28% for inspired oxygen fraction of 0.3 plus ondansetron, respectively (P = 0.279). Therefore, there was no statistically significant difference of PONV incidence among groups. CONCLUSIONS: An inspired oxygen fraction of 0.8 during general anesthesia with sevoflurane does not decrease PONV in patients undergoing strabismus repair. Ondansetron also did not significantly decrease PONV in our study setting.

Adolescent↗

PubMed2005

Conservative treatment of tracheal injuries.

Tracheal injuries, independent of their origin, may be life-threatening. Surgical repair is regarded as the treatment of choice but has not been compared with other approaches. We hypothesized that defects bridgeable by an artificial airway may enable conservative treatment. We report on five patients with tracheal injuries, two in the trachea's upper third resulting from trauma and intubation and three in its middle third after percutaneous dilational tracheostomy. Tracheal defects were bridged by endotracheal or tracheostomy tubes under bronchoscopic guidance and the cuff was inflated distal to the lesion. Air leakage stopped immediately and all tracheal defects healed without further interventions. No case of stenosis or mediastinitis was observed. These results suggest that treating tracheal injuries conservatively by placing an artificial airway under bronchoscopic guidance may be effective and offers a convenient starting position for secondary surgical repair in selected patients when conservative treatment fails.

Accidental Falls↗