Intermittent Cross-Clamp Fibrillation Versus Cardioplegic Arrest During Coronary Surgery in 6,680 Patients: A Contemporary Review of an Historical Technique.

OBJECTIVE: Myocardial management during on-pump coronary artery bypass grafting (CABG) surgery includes aortic cross-clamping followed by fibrillation (XCF) and aortic cross-clamping followed by diastolic cardioplegia (cardioplegia). The authors wished to compare in-hospital and survival outcomes between these procedures. DESIGN: A retrospective observational study utilizing propensity matching. SETTING: Tertiary Referral Centre for Heart Surgery. PARTICIPANTS: A total of 8,875 consecutive patients undergoing CABG surgery between August 1999 and February 2018. INTERVENTIONS: After 1:1 matching, the authors had 3,340 patients in the cardioplegia group and 3,340 in the XCF group. MEASUREMENTS AND MAIN RESULTS: Baseline characteristics were not significant between the matched cardioplegia and XCF groups. The XCF group had shorter pump times (61.8 minutes +/-26.8 v 74.7 minutes +/-29.5, p < 0.0001) and shorter cross-clamp times (27.80 minutes +/-10.5 v 44.44 minutes +/-18.0, p < 0.0001) compared with the cardioplegia group despite a similar median number of distal anastomoses (3 v 3, p = 0.08). After surgery, atrial arrhythmias (32% v 36%, p = 0.01) and inotropic requirement (25% v 28%, p = 0.006) were less in the XCF group compared with the cardioplegia group, respectively. Other postoperative outcomes (such as mortality and cerebrovascular events) were not statistically different. There was a mean survival advantage in using cardioplegia compared with XCF (15.4 years versus 14.7 years, log-rank, p = 0.014; 10-year survival 64% v 61% and 18-year survival 38% v 34%). CONCLUSION: This is the largest analysis of XCF. XCF does not adversely affect in-hospital outcomes. Long-term results demonstrate cardioplegic arrest may convey a survival advantage that would preclude routine XCF in the modern era.

The effect of deep hypothermia on the human pulmonary circulation.

OBJECTIVE: Acute rises in pulmonary artery pressures following complex cardiac surgery are associated with high morbidity and mortality. We hypothesised that periods of deep hypothermia predispose to elevated pulmonary pressures upon rewarming. We investigated the effect of this hypothermic preconditioning on isolated human pulmonary arteries and isolated perfused lungs. METHODS: Isometric tension was measured in human pulmonary artery rings (n=24). We assessed the constriction and dilation of these arteries at 37 °C and 17 °C. Isolated perfused human lung models consisted of lobes ventilated via a bronchial cannula and perfused with Krebs via a pulmonary artery cannula. Bronchial and pulmonary artery pressures were recorded. We investigated the effect of temperature using a heat exchanger. RESULTS: Rewarming from 17 °C to 37 °C caused a 1.3 fold increase in resting tension (p<0.05). Arteries constricted 8.6 times greater to 30 nM KCl, constricted 17 times greater to 1 nM Endothelin-1 and dilated 30.3 times greater to 100 µM SNP at 37 °C than at 17 °C (p<0.005). No difference was observed in the responses of arteries originally maintained at 37 °C compared to those arteries maintained at 17 °C and rewarmed to 37 °C. Hypothermia blunted the increase in pulmonary artery pressures to stimulants such as potassium chloride as well as to H-R but did not precondition arteries to higher pulmonary artery pressures upon re-warming. CONCLUSIONS: Deep hypothermia reduces the responsiveness of human pulmonary arteries but does not, however, precondition an exaggerated response to vasoactive agents upon re-warming.

An analysis of long-term survival after pneumonectomy for lung cancer: A retrospective study of 20 years.

INTRODUCTION: The incidence of pneumonectomy for lung cancer in the UK is continuing to decline in the era of minimally invasive thoracic surgery totalling approximately 3.5% of lung cancer resections annually. Literature is lacking for long-term survival of pneumonectomies. This study updates our previous results. Between 1998 and 2008, 206 patients underwent pneumonectomy compared to 98 patients between 2009 and 2018. METHODS: From January 1998 until December 2018, 304 patients underwent pneumonectomy. This was a retrospective study; data was analysed for age, gender, laterality, histology and time period. RESULTS: Operative mortality was 4.3% overall which was lower than the national average of 5.8%. In the last five years, there were no in-hospital, operative or 30-day mortality. During this period, 90-day mortality was 9.2%. Left-sided pneumonectomies had significantly better overall survival (3.00 vs. 2.03 years; p = 0.0015), squamous cell carcinoma (3.23 vs. 1.54 years; p = 0.00012) as well as those aged less than 70 (2.79 vs. 2.13 years; p = 0.011). There was no significant difference in survival between gender (p = 0.48). Intervention from 1998 to 2008 had significantly greater survival compared to the latter 10 years (2.68 vs. 2.46 years; p = 0.031). The Cox model shows that laterality, age, histology and time period remain significant with multivariate testing. No patient survived after 16 years. DISCUSSION: Our updated retrospective study has built on our previous results by reinforcing the success of pneumonectomies. The incidence of pneumonectomies is likely to decrease with the deployment of nation-wide lung cancer screening in the UK due to earlier detection.

Electromagnetic Navigational Bronchoscopy Learning Curve Regarding Pneumothorax Rate and Diagnostic Yield.

Electromagnetic navigational bronchoscopy (ENB) has emerged as an innovative technique for diagnosing peripheral and central nodules, offering an improved diagnostic yield compared to conventional bronchoscopy with fewer complications. That being said, pneumothorax remains a frequent complication. This retrospective study conducted at Castle Hill Hospital, UK, analysed ENB procedures over four years to assess the diagnostic yield and pneumothorax rates, exploring learning curves and procedural improvements specifically focusing on the diagnostic yield and pneumothorax rate as markers of change. A total of 246 patients underwent 358 peripheral lung biopsies, revealing an overall diagnostic yield of 61.3%. The diagnostic yield increased from 58.2% in 2020-2021 to 66.0% in 2022-2023 while the pneumothorax rate decreased significantly from 9.8% to 3.4% (p = 0.021*). The majority of pneumothorax cases occurred following upper lobe procedures. The study depicts the importance of procedural experience in improving outcomes, suggesting a learning curve effect. Additionally, it emphasizes the potential for technological advancements, such as robotic assistance, to mitigate operator-dependent variability and improve reproducibility in ENB procedures. These findings contribute to optimizing diagnostic pathways for lung lesions and improving patient safety in ENB interventions.

Impact of lung cancer screening on surgical stage distribution and surgical practice: a regional analysis of patients operated in and out of a screening program.

OBJECTIVES: The aim of this study was to assess variations in surgical stage distribution in 2 centres within the same UK region. One centre was covered by an active screening program started in November 2018 and the other was not covered by screening. METHODS: Retrospective analysis of 1895 patients undergoing lung resections (2018-2022) in 2 centres. Temporal distribution was tested using Chi-squared for trends. A lowess curve was used to plot the proportion of stage 1A patients amongst those operated over the years. RESULTS: The surgical populations in the 2 centres were similar. In the screening unit (SU), we observed a 18% increase in the proportion of patients with clinical stage IA in the recent phase compared to the early phase (59% vs 50%, P = 0.004), whilst this increase was not seen in the unit without screening. This difference was attributable to an increase of cT1aN0 patients in the SU (16% vs 11%, P = 0.035) which was not observed in the other unit (10% vs 8.2%, P = 0.41). In the SU, there was also a three-fold increase in the proportion of sublobar resections performed in the recent phase compared to the early one (35% vs 12%, P < 0.001). This finding was not evident in the unit without screening. CONCLUSIONS: Lung cancer screening is associated with a higher proportion of lung cancers being detected at an earlier stage with a consequent increased practice of sublobar resections.

Inflammatory stimuli up-regulate transient receptor potential vanilloid-1 expression in human bronchial fibroblasts.

Lung fibroblasts are involved in interstitial lung disease, chronic asthma, and chronic obstructive pulmonary disease (COPD). The expanded fibroblast population in airway disease leads to airway remodeling and contributes to the inflammatory process seen in these diseases. The cation channel transient receptor potential vanilloid-1 (TRPV1) is activated by noxious stimuli, including capsaicin, protons, and high temperatures and is thought to have a role in inflammation. Although TRPV1 expression is primarily reported to be neuronal, some extraneuronal expression has been reported. The authors therefore sought to determine whether human primary bronchial fibroblasts (HPBFs) express TRPV1 and whether inflammatory mediators can induce TRPV1 expression. The authors show that fibroblasts are predominantly TRPV1 negative; however, following stimulation with 3 common inflammatory mediators, tumor necrosis factor α (TNF-α), lipopolysaccharide (LPS), and interleukin-1α (IL-1α), TRPV1 mRNA was observed at 24 and 48 hours post treatment with all 3 mediators. Using Western blotting an increase in TRPV1 expression with all 3 inflammatory mediators was detected with significant increases seen at 72 hours post LPS and IL-1α treatment. In stark contrast to the untreated fibroblasts, significant calcium signaling in response to capsaicin and resiniferatoxin in HPBFs treated for 24 and 48 hours with TNF-α, LPS, or IL-1α was also observed. These results indicate that TRPV1 can be expressed on bronchial fibroblasts in situations where an underlying inflammatory stimulus exists, as is the case in airway diseases such as asthma and COPD.

The impact of antiarrhythmics on human pulmonary arteries: Ex vivo characterization.

Background and Aim: The safety and efficacy of the antiarrhythmic agents, amiodarone, and digoxin, in patients with pulmonary hypertension (PH), is not described well in the literature, although their use is common practice. Our study aims to investigate the effect of these drugs on pulmonary arteries (PA) which may have implications for their use in patients with PH. Methods: Human PAs were obtained from consenting patients undergoing lobectomies. Arterials rings (n=40 from ten patients) were dissected form the tissue and mounted onto a multiwire myograph. The rings were preconstricted using prostaglandin F2α before the addition of additive dilutions of amiodarone and digoxin. Finally, the reagents were washed out and the arterial rings' viability was confirmed using acetylcholine and potassium chloride. Results: Amiodarone had a slightly vasodilatory effect on the arterial rings, whereas digoxin had a relatively neutral effect. Amiodarone caused the greatest vasodilatory response at 100 µM with an active tension of -0.494 gram force with an EC50 of 9.42 µM. Digoxin produced no significant vasodilatory or vasoconstrictive response. Conclusions: This study demonstrated the ex vivo effects of amiodarone and digoxin on human pulmonary arterial tension. The results of the study showed that neither amiodarone nor digoxin had any vasoconstrictive effects. Amiodarone also exhibited vasodilatory properties and, therefore, may be used preferentially as it could help reduce the impact of PH. However, more studies need to be conducted before we can confirm the safety of these drugs. Relevance for Patients: The ambivalence surrounding treatment of postoperative arrhythmias in patients with PH results is a significant disparity between individual cases. Our study takes the first step in elucidating, in which drugs may be a safer treatment for patients with the aim to resolve the doubts clinicians may have about using these treatments. The principal goal of our work is to ensure that we are providing patients with the most effective and, more importantly, safest treatment.

Detection of microplastics in human lung tissue using µFTIR spectroscopy.

Airborne microplastics (MPs) have been sampled globally, and their concentration is known to increase in areas of high human population and activity, especially indoors. Respiratory symptoms and disease following exposure to occupational levels of MPs within industry settings have also been reported. It remains to be seen whether MPs from the environment can be inhaled, deposited and accumulated within the human lungs. This study analysed digested human lung tissue samples (n = 13) using µFTIR spectroscopy (size limitation of 3 µm) to detect and characterise any MPs present. In total, 39 MPs were identified within 11 of the 13 lung tissue samples with an average of 1.42 ± 1.50 MP/g of tissue (expressed as 0.69 ± 0.84 MP/g after background subtraction adjustments). The MP levels within tissue samples were significantly higher than those identified within combined procedural/laboratory blanks (n = 9 MPs, with a mean ± SD of 0.53 ± 1.07, p = 0.001). Of the MPs detected, 12 polymer types were identified with polypropylene, PP (23%), polyethylene terephthalate, PET (18%) and resin (15%) the most abundant. MPs (unadjusted) were identified within all regions of the lung categorised as upper (0.80 ± 0.96 MP/g), middle/lingular (0.41 ± 0.37 MP/g), and with significantly higher levels detected in the lower (3.12 ± 1.30 MP/g) region compared with the upper (p = 0.026) and mid (p = 0.038) lung regions. After subtracting blanks, these levels became 0.23 ± 0.28, 0.33 ± 0.37 and 1.65 ± 0.88 MP/g respectively. The study demonstrates the highest level of contamination control and reports unadjusted values alongside different contamination adjustment techniques. These results support inhalation as a route of exposure for environmental MPs, and this characterisation of types and levels can now inform realistic conditions for laboratory exposure experiments, with the aim of determining health impacts.

Changing clinical profiles and in-hospital outcomes of octogenarians undergoing cardiac surgery over 18 years: a single-centre experience†.

OBJECTIVES: With an ageing population, increasing numbers of octogenarians are undergoing high-risk cardiac surgery. We examine the changing characteristics and in-hospital outcomes for octogenarians over an 18-year period. METHODS: Clinical data from our prospective database for all octogenarians who had cardiac surgery from March 1999 through May 2016 were reviewed. We examined trends, risk profiles and in-hospital outcomes over 3 eras, namely early (1999-2004), middle (2005-2010) and late (2011-2016). A multivariable analysis was performed to identify independent predictors for adverse outcomes. RESULTS: There were 1022 patients aged 80-94 years in our study cohort. The octogenarian population increased progressively from early to late eras (4.5%, n = 255 vs 7.1%, n = 321 vs 9.3%, n = 446), as the average logistic EuroSCORE predicted mortality (9% vs 9.7% vs 10.1%, P < 0.01). On the contrary, observed mortality declined substantially (9.4% vs 7.8% vs 4.7%, P = 0.04) over this period. While cardiac morbidity and respiratory comorbidities were more prevalent in the late era, chronic renal failure was more frequent in the early era. Over time, more procedures were performed electively (P = 0.05). Common operations across all eras were coronary artery bypass grafting (CABG), aortic valve replacement and CABG + aortic valve replacement. Emergency operation [odds ratio (OR) 4.96, 95% confidence interval (CI) 1.51-16.35; P < 0.01], poor ejection fraction (OR 3.38, 95% CI 1.80-6.32; P < 0.01) and bypass time (OR 1.01, 95% CI 1.00-1.02; P < 0.01) were predictors of in-hospital mortality. The late era of surgery (OR 0.41, 95% CI 0.23-0.73; P < 0.01) was associated with reduced mortality risk. CONCLUSIONS: The operative outcome in this growing surgical population is steadily improving despite the increasing prevalence of comorbidities, and surgery should be performed electively as much as possible.

Are initial valve operations in octogenarians still high-risk in the current era?

BACKGROUND AND AIM OF THE STUDY: The average age of cardiac patients continues to increase. As more octogenarians undergo surgery during the current era, the outcome of valve surgery was investigated to determine the operative risk in these patients. METHODS: Among 350 patients aged > or = 80 years who had initial surgery between 1998 and 2006, a total of 188 (105 females, 83 males) underwent valve surgery. A prospective analysis was conducted of the collected data. RESULTS: The median age of patients was 82 years (IQR: 81-84 years), and over half of them presented with severe symptoms (NYHA class III/IV; n = 96), controlled heart failure (n = 108), hypertension (n = 101) and coronary artery disease (n = 108). Concomitant coronary artery bypass grafting (CABG) was performed in 89 cases (47%). Perioperative hemodynamic support with inotropes was common (47%). Hospital death after isolated aortic valve replacement (AVR) (n = 89) and mitral valve replacement (MVR) (n = 10) occurred in four patients (4.5%, median additive EuroSCORE 9.0%) and one patient (10%, median additive EuroSCORE 9.8%), respectively. Concomitant CABG led to a doubling of the operative mortality which, for AVR, declined from 5.4% to 3.8% during the latter half of the study period. The median length of stay was 24 h (IQR 21-44 h) in the intensive care unit, and 10 days (IQR 7-14 days) postoperatively. The risk factors for operative mortality were urgent/emergent surgery (HR 3.27, 95% CI 1.12-9.58, p = 0.03), preoperative gastrointestinal disease (HR 3.15, 95% CI 1.12-8.9, p = 0.03), left ventricular ejection fraction <0.30 (HR 4.37, 95% CI 1.29-14.82, p = 0.02), and ischemic time (HR 1.04, 95% CI 1.004-1.07, p = 0.02). CONCLUSION: Elective isolated AVR can be performed with modest operative risk in octogenarians with good left ventricular systolic function. Additional procedures impose long ischemic times and increase the operative risk, as does MVR. Strategies to minimize the complexity and extent of surgery should benefit these patients.

Early neurological complications after coronary artery bypass grafting and valve surgery in octogenarians.

OBJECTIVE: To determine the incidence and risk factors for neurological events complicating cardiac surgery, and the implications for operative outcome in octogenarians. METHODS: Of 6791 who underwent primary on-pump CABG and/or valve surgery from 1998 through 2006, 383 were aged > or =80 years. Neurological complications, classified as reversible or permanent, were investigated by head CT scan in patients who did not recover soon after an event. RESULTS: There were more females (47% vs 26%, p<0.0001) among octogenarians (n=383, median age 82 years) than among younger patients (n=6408, median age 66 years). Controlled heart failure, NYHA class III/IV and chronic obstructive pulmonary disease were more prevalent in octogenarians while preoperative myocardial infarction was predominant in younger patients. Octogenarians were at higher operative risk (median EuroScore 6 vs 2, p<0.0001). Operative procedures differed between octogenarians and younger patients (p<0.0001); respective frequencies were 45% vs 77% for CABG, 26% vs 10% for AVR, and 23% vs 6% for AVR+CABG. Mortality was higher for octogenarians (8.9% vs 2.1, p<0.0001). Early neurological complications observed in 3.9% of the entire study population were mostly reversible (3.2%). Age > or =80 years (odds ratio [OR] 2.82, 95% confidence interval [CI] 1.89-4.21, p<0.0001), prior cerebrovascular disease (OR 2.23, 95% CI 1.56-3.18, p<0.0001), AVR+CABG (OR 2.92, 95% CI 1.60-5.33, p<0.0001) and MVR+CABG (OR 4.77, 95% CI 2.10-10.85, p<0.0001) were predictive of neurological complications. More octogenarians experienced neurological events (p<0.0001): overall 12.8% vs 3.4%, reversible 11.5% vs 2.8%, permanent 1.3% vs 0.6%. Among octogenarians, neurological complication was associated with elevated operative mortality (18% vs 8% for those without neurological complication, p=0.03), and prolonged ventilation, intensive care stay and hospitalisation. Predictors of neurological complications in octogenarians were blood and/or blood product transfusion (OR 3.60, 95% CI 1.56-8.32, p=0.003) and NYHA class III/IV (OR 7.6, 95% CI 1.47-39.70, p=0.02). CONCLUSION: Octogenarians undergoing on-pump CABG and/or valve repair/replacement are at higher risk of neurological dysfunction, from which the majority recover fully. The adverse implications for operative mortality and morbidity, however, are profound. Blood product transfusion which has a powerful correlation with neurological complication should be reduced by rigorous haemostasis with parsimonious use of sealants when appropriate.

Is post-sternotomy percutaneous dilatational tracheostomy a predictor for sternal wound infections?

OBJECTIVE: Early post-sternotomy tracheostomy is not infrequently considered in this era of percutaneous tracheostomy. There is, however, some controversy about its association with sternal wound infections. METHODS: Consecutive patients who had percutaneous tracheostomy following median sternotomy for cardiac operation at our institution from March 1998 through January 2007 were studied, and compared to contemporaneous patients. We identified risk factors for tracheostomy, and investigated the association between percutaneous tracheostomy and deep sternal wound infection (mediastinitis) by multivariate analysis. RESULTS: Of 7002 patients, 100 (1.4%) had percutaneous tracheostomy. The procedure-specific rates were: 8.6% for aortic surgery, 2.7% for mitral valve repair/replacement (MVR), 1.1% for aortic valve replacement (AVR), and 0.9% for coronary artery bypass grafting (CABG). Tracheostomy patients differed vastly from other patients on account of older age, severe symptoms, preoperative support, lower ejection fraction, more comorbidities, more non-elective and complex operations and higher EuroScore. Risk factors for tracheostomy were New York Heart Association class III/IV (OR 6.01, 95% CI 2.28-16.23, p<0.0001), chronic obstructive pulmonary disease (OR 1.84, 95% CI 1.01-3.37, p=0.05), preoperative renal failure (OR 3.57, 95% CI 1.41-9.01, p=0.007), prior stroke (OR 3.08, 95% CI 1.75-5.42, p<0.0001), ejection fraction<0.30% (OR 2.73, 95% CI 1.23-6.07, p=0.01), and bypass time (OR 1.008, 95% CI 1.004-1.012, p<0.0001). The incidences of deep (9% vs 0.7%, p<0.0001) and superficial sternal infections (31% vs 6.5%, p<0.0001) were significantly higher among tracheostomy patients. Multivariate analysis identified percutaneous tracheostomy as a predictor for deep sternal wound infection (OR 3.22, 95% CI 1.14-9.31, p<0.0001). CONCLUSIONS: Tracheostomy, often performed in high-risk patients, may further complicate recovery with sternal wound infections, including mediastinitis, therefore, patients and timing should be carefully selected for post-sternotomy tracheostomy.

Management options for Kommerell's diverticulum.

An aberrant right subclavian artery (ARSA) arising from a left-sided aortic arch (LAA) is an uncommon aortic arch anomaly. Aneurysms of ARSA arising from different degrees of Kommerell's diverticulum may modify surgical approach. We describe a safe technique for the surgical management of ARSA aneurysm in a 67-year-old gentleman. We performed exclusion of an ARSA aneurysm using left heart bypass, with concomitant R axillary to RSCA bypass. This obviated the need for any major procedure such as an aortic arch replacement.

Harlequin syndrome following upper lobectomy.

A 58-year-old women developed unilateral facial flushing and sweating on the left side of her face immediately after a right thoracotomy upper lobectomy and paravertebral block. She was diagnosed with Harlequin syndrome in the absence of any other neurological signs or symptoms. She had recovered completely from this episode on follow-up.

Mini-extracorporeal circulation technology, conventional bypass and prime displacement in isolated coronary and aortic valve surgery: a propensity-matched in-hospital and survival analysis.

OBJECTIVES: Conventional cardiopulmonary bypass is the most commonly used means of artificial circulation in cardiac surgery. However, it suffers from the effects of haemodilution and activation of inflammatory/coagulation cascades. Prime displacement (PD) can offset haemodilution and mini-extracorporeal technology (MIECT) can offset both. So far, no study has compared all of these modalities together; hence, we compared the outcomes of these 3 modalities at our institution. METHODS: This was a retrospective analysis of our cardiac surgical database. A total of 9626 patients underwent conventional bypass (CB), 3125 patients underwent a modification of CB, called PD, and 904 underwent MIECT. A 1:1 propensity-matching algorithm was employed using IBM SPSS 24 to match (i) 813 MIECT patients with 813 CB patients and (ii) 717 MIECT patients with 717 PD patients. The patients included coronary artery bypass grafting and valve surgery. RESULTS: MIECT had significantly (P < 0.05) longer bypass and cross-clamp times compared to CB and PD. MIECT had significantly higher rates of postoperative atrial fibrillation associated with it compared to CB. The mean red cell blood transfusion was significantly lower in the MIECT group compared to the CB group as was the mean platelet transfusion and fresh frozen plasma transfusion. The overall 5-year survival was higher in the MIECT group compared to the CB group (log-rank, P = 0.018). Between the MIECT and the PD groups, we found the incidence of renal failure and gastrointestinal complications to be significantly higher in the PD group compared to the MIECT group. CONCLUSIONS: MIECT has short-term advantages over CB and PD. However, due to the retrospective limitations of the study, including calendar time bias, a multicentre randomized controlled trial comparing all 3 modalities will be beneficial for the larger cardiac community.

Pneumothorax and pregnancy.

BACKGROUND: Though more common in male patients, primary spontaneous pneumothorax might be expected to occur reasonably often in female patients of child-bearing age. However, < 50 cases of pneumothorax in pregnancy have been previously reported. Special risks are posed for both the mother and the fetus in this situation. Previous management strategies have varied widely, without describing the more modern and less invasive techniques, and existing pneumothorax guidelines do not incorporate this difficult scenario. METHODS: A retrospective search of our database of 250 spontaneous pneumothorax patients over a 10-year period, in a stable local population of 500,000 patients, identified five cases of pneumothorax occurring in pregnancy. We report our experience, the largest series yet described, review the medical literature, and make management recommendations. RESULTS: We found favorable outcomes for both mothers and infants in our series, with modern techniques such as simple aspiration, elective assisted delivery at or near term with regional anesthesia, and video-assisted thoracoscopic surgery. CONCLUSIONS: Future guidelines on the management of pneumothorax should consider the inclusion of advice on the problems of pregnancy, based on previous published experience, and utilizing the modern and less invasive techniques. Such advice would inform and support those specialists involved in managing a potentially hazardous situation to the benefit of both mother and child.

Assessing appetitive and consummatory phases of ethanol self-administration in C57BL/6J mice under operant conditions: regulation by mGlu5 receptor antagonism.

RATIONALE: The development of mouse models of ethanol consumption and ethanol-seeking behavior is of particular importance in understanding the underlying mechanisms of drug abuse because these models can enable an analysis of an effect of specific genotype on drug-seeking behavior and the interaction of potential therapeutics with genotype. However, there are some limitations with present models, notably the inability to examine appetitive and consummatory behavior separately. MATERIALS AND METHODS: In the present study, C57BL/6 mice were trained to self-administer 10% ethanol in a modified operant protocol that allowed a clear delineation of consummatory and appetitive phases. The utility of this procedure was confirmed with the use of the metabotropic glutamate 5 (mGlu5) receptor antagonist 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine (MTEP). RESULTS: Limited-access consumption during the dark phase of the light-dark cycle with intermittent access (every second or third day) led to a high level of consumption by the mice. MTEP caused a dose-dependent decrease in both the consumption of ethanol and the appetitive response for ethanol. Furthermore, this effect was unrelated to any effect of MTEP on locomotor activity. CONCLUSIONS: The model provides a useful paradigm for examining both the appetitive and consummatory phases of ethanol consumption in mice; furthermore, the data indicate mGlu5 receptors are involved in both phases.