Hypoxia decreases exhaled nitric oxide in mountaineers susceptible to high-altitude pulmonary edema

An exaggerated hypoxic pulmonary vasoconstriction is essential for development of high-altitude pulmonary edema (HAPE). We hypothesized that susceptibility to HAPE may be related to decreased production of nitric oxide (NO), an endogenous modulator of pulmonary vascular resistance, and that a decrease in exhaled NO could be detected during hypoxic exposure. Therefore, we investigated respiratory tract NO excretion by chemiluminescence and pulmonary artery systolic pressure (Ppa,s) by echocardiography in nine HAPE-susceptible mountaineers and nine HAPE-resistant control subjects during normoxia and acute hypoxia (fraction of inspired oxygen [FI(O2)] = 0.12). The subjects performed oral breathing. Nasally excreted NO was separated from respiratory gas by suction via a nasal mask. In HAPE-susceptible subjects, NO excretion in expired gas significantly decreased (p < 0.05) during hypoxia of 2 h in comparison with normoxia (28 +/- 4 versus 21 +/- 2 nl/min, mean +/- SEM). In contrast, the NO excretion rate of control subjects remained unchanged (31 +/- 6 versus 33 +/- 6 nl/ min, NS). Nasal NO excretion did not differ significantly between groups during normoxia (HAPE-susceptible group, 183 +/- 16 nl/ min; control subjects, 297 +/- 55 nl/min, NS) and was not influenced by hypoxia. The changes in Ppa,s with hypoxia correlated with the percent changes in lower respiratory tract NO excretion (R = -0.49, p = 0.04). Our data provide the first evidence of decreased pulmonary NO production in HAPE-susceptible subjects during acute hypoxia that may contribute among other factors to their enhanced hypoxic pulmonary vascular response.

Critical illness polyneuropathy and myopathy in patients with acute respiratory distress syndrome

OBJECTIVE

Critical illness polyneuropathy/myopathy (CIP/CIM) is frequently described in critically ill patients who survive severe sepsis. Clinically relevant paresis is major symptom of CIP/CIM. We aimed at determining risk factors and diagnostic value of electrophysiologic testing for CIP/CIM in patients with acute respiratory distress syndrome (ARDS).

DESIGN

Single-center, retrospective analysis, using charts.

SETTING

University medical center.

PATIENTS

Fifty consecutive ARDS patients in our intensive care unit.

INTERVENTIONS

Patient characteristics and clinical course were analyzed. All patients received early electrophysiologic testing. CIP/CIM was diagnosed by the presence of clinical relevant paresis.

MEASUREMENTS AND MAIN RESULTS

Clinically relevant paresis was confirmed in 27 ARDS patients (60%), whereas in 18 patients no paresis was determined (controls); five patients died before clinical assessment of paresis was feasible. Patients with paresis were older, had more days on mechanical ventilation, and had increased intensive care unit length of stay compared with controls. Patients who developed paresis had elevated daily peak blood glucose levels during 28 days of intensive care unit treatment: 166 (134, 200) mg/dL in CIP/CIM patients vs. 144 (132, 161) mg/dL in controls (median, quartiles). Twenty-five of 27 patients with paresis revealed reduced motor unit potentials, fibrillation potentials, or positive sharp waves on early electrophysiologic testing indicating CIP/CIM, whereas 16 of 18 control patients did not.

CONCLUSIONS

In ARDS patients, paresis is a frequent complication causing prolonged mechanical ventilation and intensive care unit length of stay. An association between hyperglycemia and CIP/CIM has been found. However, since this is a retrospective survey, a causal relation is not clearly supported. In this study, the use of early electrophysiologic testing in ARDS patients was a valuable diagnostic tool for detecting CIP/CIM.

Dose-response characteristics during long-term inhalation of nitric oxide in patients with severe acute respiratory distress syndrome: a prospective, randomized, controlled study

Inhaled nitric oxide (NO) improves systemic oxygenation (PaO2/FIO2) in adult patients with acute respiratory distress syndrome (ARDS). However, individual response varies, and previous trials demonstrated no outcome benefit. This prospective, randomized study in 40 ARDS patients analyzed dose-response (DR) characteristics during long-term inhaled NO. Patients were randomized for conventional therapy (control) or continuous treatment with 10 parts per million (ppm) inhaled NO until weaning was initiated. We measured DR curves of PaO2/FIO2 versus the inhaled NO dose at regular intervals. Before treatment (Day 0), peak improvement in PaO2/FIO2 was achieved at 10 ppm for both control and NO-treated patients. After 4 days, the DR curve of the NO-treated patients was left shifted with a peak response at 1 ppm. At higher doses (10 and 100 ppm), oxygenation deteriorated, and the response to inhaled NO disappeared in several patients. This effect was not observed in the control group. There was no effect of inhaled NO on duration of mechanical ventilation or stay at the intensive care unit. In conclusion, long-term inhaled NO with constant doses of 10 ppm leads to enhanced sensitivity after several days and does do not allow reduction of ventilation parameters. Hence, previous trials on therapy with inhaled NO in ARDS should be carefully interpreted, as they used constant NO concentrations, which may have become overdoses leading to deterioration of oxygenation after several days.

Rapid emergence of secondary resistance to gentamicin and colistin following selective digestive decontamination in patients with KPC-2-producing Klebsiella pneumoniae: a single-centre experience

After a single patient was transferred to Leipzig University Hospital from a hospital in Rhodes, Greece, the hospital experienced the largest outbreak due to a KPC-2-producing Klebsiella pneumoniae (KPC-2-KP) strain thus far observed in Germany. Ninety patients hospitalised between July 2010 and October 2012 were affected. In an attempt to eliminate KPC-2-KP from their digestive tracts, 14 consecutive patients (16%) were treated with a short course (7 days) of selective digestive decontamination (SDD), employing colistin (1 million units q.i.d.) and gentamicin (80 mg q.i.d.) as oral solutions, and applying colistin/gentamicin gel (0.5 g) to the oral cavity. In a retrospective analysis, these 14 SDD patients were compared with the remaining 76 patients harbouring KPC-2-KP. KPC-2-KP carrier status was followed in all 14 SDD patients by submitting stool samples to KPC-specific PCR. The mean follow-up period was 48 days (range 12-103 days). Successful elimination of KPC-2-KP was defined as a minimum of three consecutive negative PCR test results separated by ≥48 h each. Decolonisation of KPC-2-KP was achieved in 6/14 patients (43%) after a mean of 21 days (range 12-40 days), but was also observed in 23/76 (30%) of the non-SDD controls (P = 0.102). SDD treatment resulted in the development of secondary resistance to colistin (19% increase in resistance rate) and gentamicin (45% increase) in post-treatment isolates. In the control group, no secondary resistance occurred. We conclude that the SDD protocol applied in this study was not sufficiently effective for decolonisation and was associated with resistance development.

Reduced nitric oxide in sinus epithelium of patients with radiologic maxillary sinusitis and sepsis

Radiologic maxillary sinusitis is an important risk factor for development of bronchopneumonia in mechanically ventilated patients. Nitric oxide produced within the paranasal sinuses is considered to provide an antibacterial environment and to modulate mucociliary clearance function. We hypothesized that a reduced formation of nitric oxide might contribute to the compromised local host defense in radiologic maxillary sinusitis and measured nitric oxide levels directly within maxillary sinuses of septic patients with radiologic maxillary sinusitis (n = 11), whose sinuses were fenestrated to eliminate a possible septic focus. Data were compared with those of patients without airway inflammation (n = 11, control subjects). Despite local inflammation and infection, we found considerably lower maxillary nitric oxide levels than in control subjects (31 +/- 10 versus 2554 +/- 385 parts per billion, mean +/- standard error of the mean, p < 0.001). Consistently, immunohistochemical and in situ hybridization investigations revealed strongly reduced expression of inducible nitric oxide synthase. By applying ultrastructural immunolocalization, we identified cilia and microvilli of the maxillary sinus epithelium as the major nitric oxide production site in control subjects. Our findings provide evidence of markedly reduced nitric oxide production in maxillary sinuses of patients with radiologic maxillary sinusitis and sepsis, implicating impaired local host defense and an increased risk for secondary infections.

Long-term carriage of Klebsiella pneumoniae carbapenemase-2-producing K pneumoniae after a large single-center outbreak in Germany

BACKGROUND

The natural progress of intestinal colonization with Klebsiella pneumoniae carbapenemase-2-producing K pneumoniae (KPC-2-KP) is almost unknown.

METHODS

After a large, single-center outbreak of KPC-2-KP, we analyzed carrier prevalence through retrospective and prospective investigation of intestinal KPC-2-KP carriage 1 month, 3 months, 6 months, 1 year, and 2 years after acquisition, defined as the earliest date of KPC-2-KP detection. Rectal swabs or stool samples were collected at baseline and at each visit and submitted for both culture and KPC-specific polymerase chain reaction. Resolution of intestinal KPC-2-KP carriage was defined as a minimum of 3 consecutive negative polymerase chain reaction test results separated by at least 48 hours.

RESULTS

In patients available for long-term evaluation 26 out of 84 patients (31%) tested negative for KPC-2-KP after 1 month, 14 out of 34 (41%) after 3 months, 17 out of 26 (65%) after 6 months, 14 out of 19 (74%) after 1 year, and 5 out of 6 (83%) after 2 years. Decolonization of KPC-2-KP was hampered in patients with prolonged or repeated hospitalization (P = .044-.140, depending on the time interval). Two patients retested positive for KPC-2-KP after they had previously shown 3 consecutive negative tests. The longest positive KPC-2-KP carrier status so far was observed after nearly 40 months (1,191 days).

CONCLUSIONS

The majority of patients experienced spontaneous decolonization within 6 months after acquisition, mainly after discharge from the hospital. However, long-term carriage of >3 years is possible. Appropriate infection control measures must be taken when these patients are readmitted to health care facilities. A series of at least 4 consecutive negative rectal swabs or stool samples separated by sufficient time intervals appears necessary before the declaration of successful KPC-2-KP decolonization is made.

Motion of dark solitons in trapped bose-einstein condensates

We use a multiple time scale boundary layer theory to derive the equation of motion for a dark (or grey) soliton propagating through an effectively one-dimensional cloud of Bose-Einstein condensate, assuming only that the background density and velocity vary slowly on the soliton scale. We show that solitons can exhibit viscous or radiative acceleration (antidamping), which we estimate as slow but observable on experimental time scales.

Vascular complications related to intraaortic balloon counterpulsation: an analysis of ten years experience

We have performed a retrospective review of our experience with the intraaortic balloon counterpulsation pump (IABP) during the last decade, to identify aspects of risk factors, complications, and management that affect peripheral vascular morbidity and mortality. Data from 472 patients who had the IABP inserted during the ten-year period from December 1985 to December 1995 were retrospectively reviewed. Risk factors, implantation techniques, complications, and significant variables were evaluated. One hundred forty-five vascular complications needed surgical therapy in 116 patients. Mean age was 62.2 +/- 12.9 years. There were 84 (72.5%) men and 32 (27.5%) women. Mortality rate was 28.3% (n = 181). The mortality for patients with ischemic vascular complications was significantly higher than in patients who did not suffer any vascular complication (59.6% vs 30.1%, p = 0.0001). Complications included acute limb arterial occlusion in 99 cases (68.3%), compartment syndrome in 27 (18.6%), groin hematoma in 15 (10.3%), and persistent lymph fistula in 4 (2.8%). Of these, 97 (76.9%) occurred during IABP therapy and 29 (23.1%) after IABP explantation. Thromboembolectomy was required for 61 (42.2%) of the ischemic limbs. Associated procedures were 24 (16.5%) profundaplasties, 10 (7%) infrainguinal bypasses (5 (3.4%) femoropopliteal supragenicular, 3 (2.2%) femoropopliteal infragenicular, and 2 (1.4%) infrapopliteal), 26 (17.9%) fasciotomies, and 5 (3.4%) amputations. A history of peripheral vascular disease (31 patients [43.6%] with vs 95 [23.6%] without, p < 0.05) and the presence of diabetes mellitus (70 patients [49.2%] with vs 56 [16.9%] without) increased the risk of limb ischemia significantly. Female sex, insertion of IABP by percutaneous technique, and direct removal with groin compression were associated with higher ischemic complication rates, the differences however were not significant. Itis concluded that 1. Limb ischemia remains the primary complication after IABP insertion; 2. Femoral artery thromboembolectomy is usually sufficient for revascularisation; 3. Adequate implantation and surgical explantation techniques are essential to reduce the IABP-related morbidity; 4. Identification of subclinical disease may aid in the management of subsequent acute limb ischemia; 5. The presence of peripheral vascular disease and diabetes mellitus are associated with higher ischemic complication rates.

Exhaled nitric oxide does not provide a marker of vascular endothelial function in healthy humans

In the lung, nitric oxide synthase (NOS) has been found in both alveolar epithelial and vascular endothelial cells. Nitric oxide (NO) in the exhaled air stemming from the lower respiratory tract has been claimed to represent a marker of the vascular endothelial NO production. Experimental evidence for this concept, however, is lacking. We compared, in eight healthy volunteers, effects on exhaled NO of epithelial NOS inhibition by N (G)-monomethyl-L-arginine (L-NMMA) inhalation (6 mg/kg over 15 min) with those of endothelial NOS inhibition by L-NMMA infusion (25 microgram/kg/min for 30 min). We also measured blood pressure, heart rate, and L-NMMA plasma concentration. The major new findings were that L-NMMA inhalation which did not have any detectable effect on hemodynamics and L-NMMA plasma concentration, decreased the pulmonary exhaled NO by almost 40%. In contrast, L-NMMA infusion that inhibited endothelial NOS, as evidenced by an increase in blood pressure and a decrease in heart rate, had only a barely detectable effect on exhaled NO (-11 +/- 4% from baseline). Pulmonary exhaled NO is mostly of epithelial rather than endothelial origin, and does not provide a marker for vascular endothelial NO production and/or endothelial function in healthy humans.

Improvement of impaired renal function in heart transplant recipients treated with mycophenolate mofetil and low-dose cyclosporine

BACKGROUND

Cyclosporine (CsA) nephrotoxicity is a common problem after cardiac transplantation. We have studied the impact of CsA dose reduction in association with mycophenolate mofetil (MMF) treatment on renal function in heart transplant recipients with suspected CsA nephrotoxicity (serum creatinine level >2 mg/dl).

METHODS

Twelve heart transplant recipients (11 men, 1 woman; 111 to 1813 days after transplantation) with CsA-based immunosuppression (plus azathioprine and/or steroids) and a serum creatinine level >2.0 mg/dl were started on a daily dose of 2000 mg of MMF. Dilated cardiomyopathy was the underlying disease in nine patients, ischemic cardiomyopathy in three patients. Mean patient age was 57 years (range 44-69 years). Azathioprine was discontinued and CsA slowly tapered. Creatinine clearance, serum creatinine level, urea nitrogen, and uric acid were monitored. CsA levels were measured, and CsA dose was adjusted for whole blood levels of 70-120 microg/L. Ten patients still had endomyocardial biopsies, whereas one had echocardiographic controls only.

RESULTS

One grade 1B rejection episode according to ISHLT (International Society for Heart and Lung Transplantation) was observed until 1 year after the switch to MMF. One patient was excluded due to gastrointestinal side effects.

CONCLUSIONS

Conversion from azathioprine to MMF with consecutive reduction of CsA in heart transplant recipients with CsA-impaired renal function improves renal function as evidenced by lower serum creatinine, urea nitrogen, uric acid, and higher creatinine clearance.

Dark-bright solitons in inhomogeneous Bose-Einstein condensates

We investigate dark-bright vector solitary wave solutions to the coupled nonlinear Schrödinger equations which describe an inhomogeneous two-species Bose-Einstein condensate. While these structures are well known in nonlinear fiber optics, we show that spatial inhomogeneity strongly affects their motion, stability, and interaction, and that current technology suffices for their creation and control in ultracold trapped gases. The effect of controllably different interparticle scattering lengths is examined, and stability against three-dimensional deformations is considered.

Chest re-exploration for complications after lung surgery

BACKGROUND

Review of the most recent chest re-explorations for lung surgery complications may show methods by which risks can effectively be reduced.

METHODS

The data on rethoracotomies following lung surgery over the past 14 years in our department were retrospectively reviewed. The indication, the type of operation, the outcome, and various factors influencing the postoperative mortality were analyzed. From 1983 to 1996, 1960 patients underwent primary thoracotomies for various lung diseases. Among these, 73 (3.7%) patients required re-exploration for various postoperative complications.

RESULTS

Mean age was 56.8 years (15-80 years). There were 66 (90.4%) men and 7 (9.6%) women. The most common indication for rethoracotomy was hemorrhage in 38 (52%) patients. The source of bleeding was a mediastinal and/or bronchial blood vessel in 8 patients and an intercostal blood vessel in 6 patients. Six patients had to be reoperated because of hemorrhage from a major artery of the hilus. In 14 cases the postoperative hemothorax occurred without evident surgical origin. Further indications for rethoracotomy were bronchopleural fistula (BPF) in 13 (17.8%) patients, and persistent parenchymal leak in 8 (10.9%) patients. There were 8 additional causes distributed among the remaining 14 (19.3%) patients. The overall mortality rate was 17.8% (13/73), with the highest (38.4%) among BPF patients.

CONCLUSIONS

Postoperative complications following lung surgery which require rethoracotomy are rare. The most common complication is postoperative bleeding. This is followed by bronchial stump insufficiency which is associated with the highest mortality and morbidity. Our experience shows that the need for re-exploration can hardly be reduced but the indication for re-exploration should be established as early as possible to avoid late complications.

Myocardial consequences of remifentanil in patients with coronary artery disease

Remifentanil may be an alternative to conventional opioids for minimally invasive direct coronary artery bypass surgery because of its extremely short duration of action. The aim of this study was to investigate the effects of remifentanil on myocardial blood flow, metabolism and systemic haemodynamic variables in patients with coronary artery disease. After approval by the local ethics committee, 12 male patients were investigated before elective coronary artery bypass grafting. Systemic haemodynamic variables, myocardial blood flow and metabolism were measured when patients were awake and when they were anaesthetized with high-dose remifentanil (2.0 micrograms kg-1 min-1), or with remifentanil 0.5 microgram kg-1 min-1 combined with propofol (target-controlled infusion aiming at a plasma concentration of 2.0 micrograms ml-1). Myocardial blood flow was measured using a modified Kety-Schmidt technique. High-dose remifentanil anaesthesia significantly reduced cardiac index (CI) (-25%) as a consequence of a decrease in stroke volume index (SVI) (-14%) and heart rate (-13%). Mean arterial pressure (MAP) was 30% lower than that in the awake patient. Myocardial blood flow and myocardial oxygen uptake (MVO2) decreased by 30% and 42%, respectively. In contrast to high-dose remifentanil anaesthesia, systemic vascular resistance index (-14%) during remifentanil/propofol anaesthesia was significantly lower than that in the awake patient. Other haemodynamic variables, and myocardial blood flow and MVO2, did not significantly differ from the high-dose remifentanil period. In conclusion, high-dose remifentanil reduces SVI, heart rate, MAP, myocardial blood flow and MVO2 and its effects do not differ from those of remifentanil/propofol anaesthesia.

Epidemiology and Resistance Patterns of Bacterial and Fungal Colonization of Biliary Plastic Stents: A Prospective Cohort Study

Background

Plastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stent-associated biofilms, with particular emphasis on antimicrobial resistance.

Methods

Patients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH).

Results

Among 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1–1274 days). The stent occlusion rate was 11.5% and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycin-resistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for 32.9% of the respective isolates.

Conclusions

Enterococci and Candida species play an important role in the microbial colonization of biliary stents. Therefore, empirical antimicrobial treatment of stent-associated cholangitis should be guided toward enterococci, Enterobacteriaceae, streptococci, anaerobes, and Candida. To determine causative pathogens, an accurate microbiological analysis of the extracted stent(s) may be helpful.

Childhood asthma: exhaled nitric oxide in relation to clinical symptoms

Bronchial asthma is associated with increased levels of exhaled nitric oxide which are suppressible by glucocorticosteroid inhalation. Children with bronchial asthma were studied to elucidate the relation between endogenous NO release and recent symptoms of bronchial obstruction. Twenty-five children with atopic asthma and 11 healthy control subjects were enrolled and exhaled NO was studied using chemiluminescence analysis. The subjects breathed purified air (<0.5 parts per billion (ppb) NO) exclusively through their mouths. Orally expired NO was measured during continuous nasal aspiration (1.3 L x min(-1)) to remove nasally produced NO. Nasal NO concentration was determined within the aspirated gas. Orally expired NO concentration was 2.5+/-0.3 ppb (mean +/-SEM) in healthy control subjects, 3.19+/-0.88 ppb (NS) in symptom-free children, and 8.28+/-0.81 ppb (p< or =0.01) in children with bronchial asthma who had had recent symptoms of bronchial obstruction. Similarly, in the subgroup of children treated regularly with inhaled glucocorticosteroids those with recent symptoms had significantly higher orally exhaled NO concentrations than healthy control subjects (9.5+/-1.5 ppb, p<0.05). The nasal NO concentration was 152.8+/-12.7 ppb in healthy control subjects and not significantly different in asthmatic children. In this group of asthmatic children, recent symptoms of bronchial obstruction were linked to significantly higher concentrations of NO in orally exhaled gas and to increased oral NO excretion rates. If substantiated by further studies, measurement of orally exhaled NO during nasal aspiration may become useful to monitor disease control in asthmatic children.

Association Studies and Direct DNA Sequencing Implicate Genetic Susceptibility Loci in the Etiology of Nonsyndromic Orofacial Clefts in Sub-Saharan African Populations

Orofacial clefts (OFCs) are congenital dysmorphologies of the human face and oral cavity, with a global incidence of 1 per 700 live births. These anomalies exhibit a multifactorial pattern of inheritance, with genetic and environmental factors both playing crucial roles. Many loci have been implicated in the etiology of nonsyndromic cleft lip with or without cleft palate (NSCL/P) in populations of Asian and European ancestries, through genome-wide association studies and candidate gene studies. However, few populations of African descent have been studied to date. Here, the authors show evidence of an association of some loci with NSCL/P and nonsyndromic cleft palate only (NSCPO) in cohorts from Africa (Ghana, Ethiopia, and Nigeria). The authors genotyped 48 single-nucleotide polymorphisms that were selected from previous genome-wide association studies and candidate gene studies. These markers were successfully genotyped on 701 NSCL/P and 163 NSCPO cases, 1,070 unaffected relatives, and 1,078 unrelated controls. The authors also directly sequenced 7 genes in 184 nonsyndromic OFC (NSOFC) cases and 96 controls from Ghana. Population-specific associations were observed in the case-control analyses of the subpopulations, with West African subpopulations (Ghana and Nigeria) showing a similar pattern of associations. In meta-analyses of the case-control cohort, PAX7 (rs742071, P = 5.10 × 10(-3)), 8q24 (rs987525, P = 1.22 × 10(-3)), and VAX1 (rs7078160, P = 0.04) were nominally associated with NSCL/P, and MSX1 (rs115200552, P = 0.01), TULP4 (rs651333, P = 0.04), CRISPLD2 (rs4783099, P = 0.02), and NOG1 (rs17760296, P = 0.04) were nominally associated with NSCPO. Moreover, 7 loci exhibited evidence of threshold overtransmission in NSOFC cases through the transmission disequilibrium test and through analyses of the family-based association for disease traits. Through DNA sequencing, the authors also identified 2 novel, rare, potentially pathogenic variants (p.Asn323Asp and p.Lys426IlefsTer6) in ARHGAP29 In conclusion, the authors have shown evidence for the association of many loci with NSCL/P and NSCPO. To the best of this knowledge, this study is the first to demonstrate any of these association signals in any African population.

Selective pulmonary vasodilation in acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is characterized by a marked maldistribution of pulmonary perfusion in favor of nonventilated, atelectatic areas of the lungs, and it is the main cause of pulmonary right-to-left shunting and hypoxemia. Therapeutic interventions to selectively influence pulmonary perfusion in ARDS became feasible with the introduction of inhaled nitric oxide, which provided a means not only to reduce pulmonary hypertension, but also to improve matching of ventilation to perfusion and, thus, hypoxemia. Clinical studies in ARDS subsequently demonstrated that the combination of inhaled nitric oxide with other interventions, such as positive end-expiratory pressure and prone positioning, yielded beneficial and additive effects on arterial oxygenation. Although the available randomized, controlled trials of this novel concept have so far failed to show an improved outcome in ARDS, inhaled nitric oxide is a clinically valuable option for the treatment of severe refractory hypoxemia in ARDS, and largely promoted the concept of selective pulmonary vasodilation in intensive care practice. Currently, aerosolization of various vasodilators, in particular prostaglandins, is under evaluation in models of acute lung injury and human ARDS. Ongoing research aims to augment the effectiveness of vasodilators with specific inhibitors of phosphodiesterases or by combination with intravenous vasoconstrictors. Consequently, several alternative ways to selectively modulate pulmonary vascular tone in patients with ARDS may be available in the near future. Cost-benefit analysis of these therapeutic options will largely determine their future perspective.

Ischaemic complications with intra-aortic balloon counter-pulsation: incidence and management

The most important limitation of the use of the intra-aortic balloon pump is the risk of vascular complications. The aim of this study was to identify risk factors and aspects of diagnosis and management that may decrease the risk of vascular morbidity associated with intra-aortic balloon pumps. Risk factors, surgical techniques, complications and other variables were retrospectively evaluated in 524 patients who had an intra-aortic balloon pump inserted between January 1988 and December 1998. Of the total, 140 (26.7%) patients with an intra-aortic balloon pump had ischaemic complications that needed surgery. The mean age was 65.2 +/-12.3 years (66.7% men and 27.5% women). The mortality rate was 28.1%. The mortality for patients with ischaemic vascular complications was significantly higher than in those patients without (59.6 versus 30.1%, P = 0.001). One-hundred and eight (77.2%) ischaemic complications occurred during therapy with an intra-aortic balloon pump and 32 (22.8%) complications after intra-aortic balloon pumping had been stopped. Thromboembolectomy was required in 71 (50.7%) patients. Associated surgical procedures were performed in 69 (49.3%) patients. A history of peripheral vascular disease (43.6 versus 23.6%, P < 0.05) and the presence of diabetes mellitus (49.2 versus 16.9%, P < 0.05) increased the risk of limb ischaemia significantly. Limb ischaemia remains the major complication after intra-aortic balloon pump insertion. Independent predictors for vascular complications included peripheral vascular disease and diabetes. Intra-aortic balloon pump removal and thrombectomy is usually sufficient to provide revascularization. Identification of subclinical disease may aid in the management of subsequent acute limb ischaemia.