Lung Volume Reduction Surgery Reduces Pulmonary Arterial Hypertension Associated With Severe Lung Emphysema and Hypercapnia.

Lung volume reduction surgery (LVRS) represents a standard surgical approach for patients with severe pulmonary emphysema. One of the relevant risk factors for LVRS is the presence of pulmonary arterial hypertension (PAH). The aim of this study is to assess the postoperative changes in pulmonary arterial pressure (PAP) after LVRS for patients with severe pulmonary emphysema compared with preoperative measures. N = 61 consecutive patients with severe pulmonary emphysema and preoperative evidence for PAH (pulmonary arterial systolic pressure [PASP] ≥ 35 mmHg) were prospectively included into this study. In all patients, thoracoscopic LVRS was performed. PASP was assessed by echocardiography before surgery, early postoperatively, and 3 months after surgery. Data were prospectively recorded and analyzed retrospectively. Primary end points were the postoperative changes in PASP as well as the 90 day mortality rate. Secondary endpoints included: pulmonary function test, exercise capacity, quality of life, and dyspnea symptoms (Borg scale). Early after surgery, a significant reduction in PASP was observed at the day of discharge and at 3 month follow-up. In n = 34 patients, no tricuspid valve regurgitation was detectable anymore suggesting normal PAP. In n = 3 patients, venovenous extracorporeal lung support (VV ECLS) was already implemented preoperatively. In the remaining cases, VV ECLS was applied intraoperatively and continued postoperatively. Mean duration of postoperative ECLS support was 2 days. Four patients died due to acute right heart failure, two patients from sepsis with multiorgan failure, and one patient from acute pulmonary embolism. Ninety day mortality was 11.5 %. A significant improvement was postoperatively observed regarding the performance status, dyspnea scale, as well as quality of life. This study suggests a beneficial effect of LVRS on PAP, which may ultimately help to protect and stabilize right ventricular function. Further studies, implementing pre- and postoperative right heart catheterizations including invasive PAP evaluation, are necessary to support the findings in this study in greater detail.

Dexmedetomidine versus propofol for operator-directed nurse-administered procedural sedation during catheter ablation of atrial fibrillation: A randomized controlled study.

BACKGROUND: Operator-directed nurse-administered (ODNA) sedation with propofol (PRO) is the preferred sedation technique for catheter ablation of atrial fibrillation (AF) in many centers. OBJECTIVE: The purpose of this study was to investigate whether dexmedetomidine (DEX), an α2-adrenergic receptor agonist, is superior to propofol. METHODS: We randomized 160 consecutive patients undergoing first AF ablation to ODNA sedation by DEX (DEX group) vs PRO (PRO group), according to a standardized protocol. Patients were unaware of treatment allocation. The primary endpoint was a composite of inefficient sedation, termination/change of sedation protocol or procedure abortion, hypercapnia (transcutaneous CO2 >55 mm Hg), hypoxemia (SpO2 <90%) or intubation, prolonged hypotension (systolic blood pressure <80 mm Hg), and sustained bradycardia necessitating cardiac pacing. Secondary endpoints were the components of the primary endpoint and patient satisfaction with procedural sedation, as assessed by a standardized questionnaire given the day after ablation. RESULTS: The primary endpoint occurred in 15 DEX group and 25 PRO group patients (19% vs 31%; P = .068). Hypercapnia was significantly more frequent in PRO group patients (29% vs 10%; P = .003). There was no significant difference for the other components of the primary endpoint, and no procedure was aborted. Patient satisfaction was significantly better among PRO group patients (visual analogue scale 0-100; median 100 in PRO group vs median 93 in DEX group; P <.001). CONCLUSION: Efficacy of ODNA sedation with DEX was not different from that with PRO. Hypercapnia occurs less frequently with DEX, but patient satisfaction is better with PRO sedation. In selected patients, DEX may be used as an alternative to PRO for ODNA sedation during AF ablation.

Veno-Venous Extracorporeal Lung Support as a Bridge to or Through Lung Volume Reduction Surgery in Patients with Severe Hypercapnia.

Extracorporeal lung support (ECLS) represents an essential support tool especially for critically ill patients undergoing thoracic surgical procedures. Lung volume reduction surgery (LVRS) is an important treatment option for end-stage lung emphysema in carefully selected patients. Here, we report the efficacy of veno-venous ECLS (VV ECLS) as a bridge to or through LVRS in patients with end-stage lung emphysema and severe hypercapnia. Between January 2016 and May 2017, 125 patients with end-stage lung emphysema undergoing LVRS were prospectively enrolled into this study. Patients with severe hypercapnia caused by chronic respiratory failure were bridged to or through LVRS with low-flow VV ECLS (65 patients, group 1). Patients with preoperative normocapnia served as a control group (60 patients, group 2). In group 1, VV ECLS was implemented preoperatively in five patients and in 60 patients intraoperatively. Extracorporeal lung support was continued postoperatively in all 65 patients. Mean length of postoperative VV ECLS support was 3 ± 1 day. The 90 day mortality rate was 7.8% in group 1 compared with 5% in group 2 (p = 0.5). Postoperatively, a significant improvement was observed in quality of life, exercise capacity, and dyspnea symptoms in both groups. VV ECLS in patients with severe hypercapnia undergoing LVRS is an effective and well-tolerated treatment option. In particular, it increases the intraoperative safety, supports de-escalation of ventilatory strategies, and reduces the rate of postoperative complications in a cohort of patients considered "high risk" for LVRS in the current literature.

Effects of hypercapnia on postoperative nausea and vomiting after laparoscopic surgery: a double-blind randomized controlled study.

BACKGROUND: Laparoscopic surgery is associated with a high incidence of postoperative nausea and vomiting (PONV). The use of CO2 pneumoperitoneum has been proposed as a potential cause of high PONV incidence. However, intraoperative hypercarbia may be related to enhanced perfusion to the main effector sites for PONV, including the brain and gastrointestinal tract. In this study, we investigated whether an increase in intraoperative CO2 partial pressure in arterial blood (PaCO2) reduces the incidence of PONV. METHODS: This study enrolled 400 female patients aged 20-60 years who were undergoing laparoscopic gynecologic surgery. The patients were allocated randomly to one of three groups with the following intraoperative PaCO2 levels: 36-40 mmHg (Group 1), 41-45 mmHg (Group 2), or 46-50 mmHg (Group 3). The anesthetic regimen used a standardized total intravenous anesthesia consisting of propofol and remifentanil for all patients. The arterial blood gas analysis was performed to identify the difference in CO2 partial pressure between arterial blood and end-tidal gas. The PONV incidence was evaluated for the periods of 0-2, 2-6, and 6-24 h after anesthesia. The incidence and severity of PONV and the administration of rescue antiemetics were recorded. RESULTS: The three groups were comparable for the patient, anesthesia, and surgical characteristics. The average PaCO2 level during surgery was 38-39, 43-44, and 47-48 mmHg in Groups 1, 2, and 3, respectively. The incidence and severity of PONV and use of rescue antiemetics were not significantly different among the groups. The overall incidence of nausea during the first 24-h postoperative period was 54, 48, and 50% in Groups 1, 2, and 3, respectively (P = 0.593). CONCLUSION: Our data suggest that mild to moderate intraoperative hypercapnia did not decrease the incidence and severity of PONV or the requirement for rescue antiemetics after gynecologic laparoscopic surgery.

Cardiac autonomic ganglia ablation suppresses atrial fibrillation in a canine model of acute intermittent hypoxia.

BACKGROUND: Atrial fibrillation (AF) is associated with hypoxia in which cardiac autonomic nerve system (ANS) plays an important role. Our previous studies indicated that ANS is activated in an intermittent hypoxia model and contributes to AF initiation. This study aimed to investigate the effects of cardiac ganglionated plexus (GP) ablation on AF in this model. METHODS AND RESULTS: In thirteen anesthetized male dogs, GP ablation was applied after 1h of intermittent hypoxia in the first group (n=7) and before that in the second group (n=6). The heart rate (HR), blood pressure (BP), arterial blood gases, heart rate viability indices, atrial effective refractory period (ERP) and window of vulnerability (WOV), the sum of WOVs (ΣWOV) were measured. In both groups, HR, BP increased and then declined during hypoxia, and not significantly affected by GP ablation. Hypoxemia, hypercapnia and acidosis were observed after intermittent hypoxia. In the first group, both of low frequency power (LF) and high frequency power (HF) increased during hypoxia. At the end of intermittent hypoxia, LF/HF ratio decreased, ERP shortened and ΣWOV increased. The following GP ablation resulted in increases in LF, LF/HF, ERP and decreases in HF, ΣWOV. In the second group, GP ablation caused increases in LF, LF/HF, ERP and decrease in HF. Subsequently, ERP shortened at several sites after intermittent hypoxia. However, there were no significant changes in LF/HF ratio or ΣWOV. CONCLUSIONS: Cardiac ANS plays an important role in hypoxia-induced AF. AF associated with hypoxia might be prevented or reversed by GP ablation.

Endoscopic lung volume reduction coil treatment in patients with chronic hypercapnic respiratory failure: an observational study.

BACKGROUND: Endoscopic lung volume reduction coil (LVRC) treatment is an option for selected patients with severe emphysema. In the advanced stages, emphysema leads to respiratory failure: hypoxemia and eventually chronic hypercapnic respiratory failure. It can be hypothesized that LVRC treatment, a procedure targeting hyperinflation and thereby reducing ventilatory workload, may be especially beneficial in patients with chronic hypercapnic respiratory failure. This study was conducted to gain first insights into the effects and the safety of LVRC treatment in patients with emphysema and chronic hypercapnic respiratory failure. METHODS: A retrospective observational study conducted in the Department of Respiratory Medicine at the University Medical Center Hamburg-Eppendorf, Germany on all patients with chronic hypercapnic respiratory failure in whom bilateral LVRC treatment was performed between 1 April 2012 and 30 September 2015. RESULTS: During the study period, bilateral LVRC treatment was performed in 10 patients with chronic hypercapnic respiratory failure. Compared with baseline, bilateral LVRC treatment led to a significant increase in mean forced expiratory volume in one second (FEV1) from 0.5 ± 0.1 l to 0.6 ± 0.2 l ( p = 0.004), a decrease in residual volume (RV) from 6.1 ± 0.9 l to 5.6 ± 1.1 l ( p = 0.02) and a reduction in partial pressure of carbon dioxide in arterial blood (PaCO2) from 53 ± 5 mmHg to 48 ± 4 mmHg ( p = 0.03). One case of hemoptysis requiring readmission to hospital was the only severe adverse event. CONCLUSIONS: LVRC treatment was safe and effective in patients with nonsevere chronic hypercapnic respiratory failure. It led not only to an improvement in lung function but also to a significant decrease in PaCO2.

Intraoperative Management of Hypercapnia With an Extracorporeal Carbon Dioxide Removal Device During Giant Bullectomy.

Extracorporeal CO2-removal devices have been introduced in clinical practice to provide protective and ultraprotective ventilation strategies in different settings to avoid retention of carbon dioxide. The need to facilitate lung-protective ventilation is required not only for the treatment of acute respiratory distress syndrome but also in thoracic surgery during complex operations, especially in respiratory compromised patients. This report describes a case of giant bullectomy for vanishing lung syndrome in which intraoperative hypercapnia secondary to protective ventilation was managed with a CO2-removal device (Decap-Hemodec s.r.l., Salerno, Italy). To the best of our knowledge, this is the first report in the literature of the intraoperative use of the Decap system for giant bullectomy.

Normalization of cerebral vasoreactivity using BOLD MRI after intravascular stenting.

BACKGROUND AND PURPOSE: Intravascular angioplasty and stenting of intracranial arterial stenosis provided controversial results. Besides the expertise of the practitioners, the selection of the patients remains challenging. BOLD MRI of the cerebral vasoreactivity (BOLD MRI CVR) to hypercapnia provides reproducible maps of the entire brain of the vascular reserve, and could be helpful to assess the best therapeutic strategy. CASE HISTORY: We report the case of a 63-year-old woman referred for a severe stenosis of the proximal portion of the left middle cerebral artery, revealed by a lenticulostriate and precentral infarction. Despite an aggressive medical treatment during 5 months, the occurrence of iterative transient ischemic attacks motivated intravascular stenting. Functional MRI of the vasoreactivity to hypercapnia using both Blood Oxygen Level Dependent (BOLD) and arterial spin labeling sequences showed normal basal perfusion and impaired vasoreactivity in the left middle cerebral artery territory. Three months after stenting, the BOLD MRI CVR showed vasoreactivity normalization. Since, the patient remains free of ischemic disorders one year after stenting. CONCLUSION: BOLD MRI of the CVR to hypercapnia may be helpful to optimize the treatment of patients with intracranial arterial stenosis, and could be performed in future therapeutic trials.

Use of extracorporeal membrane lung assist device (Novalung) in H1N1 patients.

We present three patients with severe respiratory failure secondary to H1N1 influenza type A pneumonitis, in whom hypercapnia and respiratory acidosis were not controlled by the conventional mechanical lung ventilation or high-frequency oscillatory ventilation. Use of a pumpless arteriovenous extracorporeal carbon dioxide removal device (Novalung™, Inspiration Healthcare Ltd, Leicester, UK) resulted in reduced carbon dioxide levels, improved pH, and a reduction in inspiratory pressures, allowing for a less-harmful ventilator strategy. These cases demonstrate that the Novalung is a safe and effective device to use in patients with H1N1 pneumonitis refractory to the conventional therapy and may be an alternative to extracorporeal membrane oxygenation (ECMO) in selected cases.

Bronchoconstriction during alveolar hypocapnia and systemic hypercapnia in dogs with a cardiopulmonary bypass.

The roles of the alveolar and systemic CO2 on the lung mechanics were investigated in dogs subjected to cardiopulmonary bypass. Low-frequency pulmonary impedance data (Z(L)) were collected in open-chest dogs with an alveolar CO2 level (FA(CO2)) of 0.2-7% and during systemic hypercapnia before and after elimination of the vagal tone. Airway resistance (R(aw)), inertance (I(aw)), parenchymal damping (G) and elastance (H) were estimated from the Z(L). The highest R(aw) observed at 0.2% FA(CO2),which decreased markedly up to a FA(CO2) of 2% (212 ± 24%), and remained unchanged under normo- and hypercapnia (FA(CO2) 2-7%). These changes were associated with smaller decreases in I(aw) (-16.6 ± 3.7%), mild elevations in G (25.7 ± 4.7%), and no change in H. Significant increases in all mechanical parameters were observed following systemic hypercapnia; atropine counteracted the R(aw) rises. We conclude that severe alveolar hypocapnia may contribute to minimization of the ventilation-perfusion mismatch by constricting the airways in poorly perfused lung regions. The constrictor potential of systemic hypercapnia is mediated by vagal reflexes.

Hypoxemia and hypoventilation syndrome improvement after laparoscopic bariatric surgery in patients with morbid obesity.

BACKGROUND: The objective of this study was to evaluate the relationship between oxygen partial pressure (pO(2)), awake oxymetric saturation (SpO(2)), body mass index (BMI), and percentage of excess weight loss (EWL) in extremely severe obesity (BMI >50 kg m(-2)) and hypoxemia, before and after laparoscopic Roux-en-Y gastric bypass. PATIENTS AND METHODS: A group of 11 obese patients aged 41.2 + or - 10.2 years (4 men, 7 women, median BMI=52.3 kg/m(2), range 50.2-57.1) were prospectively enrolled in the study. BMI, arterial blood gas measurements, and spirometry were obtained before and after (6 and 12 months) surgery. RESULTS: The main preoperative parameters were SpO(2)=88.3 + or - 3.9%, predicted forced vital capacity (FVC)=84.5 + or - 8.3%, predicted forced expiratory volume exhaled in one second (FEV1)=79.9+/-10.1%. No relationship (p>0.01) was found between BMI, SpO(2), and FEV1. A significant correlation between SpO(2) and both paO(2) (R=0.74, p=0.009) and EWL (R=-0.75, p=0.008) was found. Three, 6, and 12 months after surgery EWL was 18.9%, 26.4%, and 39.6% (p<0.001), respectively. At one-year follow-up SpO(2), FVC, and FEV1 were 96.2 + or - 3.2% (p<0.001), 112.3 + or - 9.9% (p<0.001), and 101.6 + or - 18.8% (p=0.003), respectively. CONCLUSION: In patients with extremely severe obesity, bariatric surgery may improve significantly both SpO(2) and spirometric parameters, and EWL represents the factor that impacted the results.

Reoperation for parathyroid adenoma: a contemporary experience.

BACKGROUND: We reviewed reoperations for persistent or recurrent sporadic parathyroid adenoma to evaluate and compare our current results and outcomes to our previous experience. METHODS: From 1996 to 2008, 237 patients with persistent or recurrent hyperparathyroidism after failed operation underwent reoperation. Patients were re-explored with the assistance of non-invasive and sometimes invasive imaging. RESULTS: A missed adenoma was suspected pre-operatively in 163 patients. Reoperation resulted in long-term resolution of hypercalcemia in 92%. Adenomas were in entopic locations in 32%; the most frequent ectopic location was the thymus (20%). Sestamibi scanning and ultrasonography were the most successful non-invasive imaging studies (96% positive predictive value (PPV) and 84% PPV respectively). Forty-four percent of patients had a reoperation based solely on non-invasive imaging. Of the invasive procedures performed, arteriography resulted in the best localization (92% PPV). Permanent recurrent laryngeal nerve injury occurred in 1.8%. CONCLUSION: Compared to our prior experience (1982-1995), outcomes remained similar (92% resolution of hypercalcemia and 1.8% recurrent nerve injury currently versus 96% and 1.3% previously). Fewer patients received invasive studies for pre-operative localization (56% vs 73%, respectively). The decreased use of invasive imaging is due to technical improvements and greater confidence in the combination of ultrasonography and sestamibi scanning.

Severe bullous emphysema and hypercapnia successfully treated by bronchoscopic lung volume reduction.

Patients with severe COPD may develop hypercapnic respiratory failure requiring mechanical ventilation and are at risk of becoming ventilator-dependent. We describe a patient with uncontrollable hypercapnic respiratory failure on mechanical ventilation whose respiratory condition and life were improved after bronchoscopic lung volume reduction. Further discussion of the possibility of bronchoscopic lung volume reduction in patients who require mechanical ventilation due to hypercapnic respiratory failure is warranted.

Congenital diaphragmatic hernia in 120 infants treated consecutively with permissive hypercapnea/spontaneous respiration/elective repair.

BACKGROUND/PURPOSE: Poor prognosis (approximately 50% survival rate and significant morbidity) traditionally has been associated with congenital diaphragmatic hernia (CDH). The authors reviewed a single institution experience and challenged conventional wisdom in the context of a care strategy based on permissive hypercapnea/spontaneous respiration/elective repair. METHODS: From August 1992 through February 2000, all infants with CDH and (1) respiratory distress requiring mechanical ventilation, (2) in-born or (3) transferred preoperatively within hours of birth are reported. All respiratory care strategy used permissive hypercapnea/spontaneous respiration and combined with elective repair. Arterial blood gas values and concomitant ventilator support were recorded. Outcome markers were (1) need for extracorporeal membrane oxygenation ECMO, (2) discharge to home, (3) supplemental oxygen need at discharge, and (4) influence of non-ECMO ancillary therapies (surfactant, nitric oxide, high-frequency oscillatory ventilation). RESULTS: One hundred twenty consecutive infants were reviewed. Overall survival rate was 75.8%, but, excluding 18 of 120 not treated (6 lethal anomalies, 10 overwhelming pulmonary hypoplasia, 3 prerepair ECMO-related neurocomplications), 84.4% survived to discharge. A total of 67/120 were inborn. Non-ECMO ancillary treatments had no impact on survival rate. ECMO was used in 13.3%. Surgery was transabdominal; prosthetics were used in 7%. Tube thoracostomy was rare. Every inborn patient (n = 11) requiring a chest tube for pneumothorax died. Respiratory support before surgery was peak inspiratory pressure (PIP), 22, FIO(2),.43 with PaO(2), 66 torr; PaCO(2), 41 torr; and pH, 7.32. The survivors discharged on oxygen (n = 2) died at 4 and 7 months. CONCLUSIONS: The majority of infants with life-threatening CDH treated with permissive hypercapnea/spontaneous respiration/elective surgery survive to discharge with minimal pulmonary morbidity.

Significance of percutaneous cardiopulmonary bypass support for volume reduction surgery with severe hypercapnia.

In patients with reduced respiratory function, lung resection is associated with high risk because separate ventilation is generally needed for safe management. For patients with end-stage emphysema, intraoperative respiratory management is important and particularly difficult because neither incomplete oxygenation nor selective ventilation can be performed, so the operation may be interrupted. In this study, we assess the effectiveness of the percutaneous cardiopulmonary support (PCPS) system for lung volume reduction surgery in patients with severe hypercapnia (arterial carbon dioxide tension >50 mm Hg) and discuss the significance of PCPS for patients who are beyond the standard criteria for lung volume reduction surgery (LVRS). We studied 3 patients with severe hypercapnia due to emphysema who underwent volume reduction surgery. One patient was previously treated surgically for contralateral pneumothorax. All patients had a severe smoking history and were suspected to have fragile lungs. During the operation. PCPS provided sufficient support flow. Intraoperative management using PCPS was easy, and no severe complications were observed. One patient exhibited severe hemodynamic deterioration on postoperative Day 15. Other patients' PaCO2 improved postoperatively. One had a calcification of a femoral artery, but there was no trouble inserting a cannula. Bilateral or unilateral volume reduction surgery was performed under PCPS in patients with end-stage emphysema. We conclude that PCPS is an adjunct to LVRS, useful for intraoperative management of some patients with severe hypercapnea, and the LVRS indications can be extended.

Improvements in lung function, exercise, and quality of life in hypercapnic COPD patients after lung volume reduction surgery.

STUDY OBJECTIVE: To determine the impact of preoperative resting hypercapnia on patient outcome after bilateral lung volume reduction surgery (LVRS). METHODS: We prospectively examined morbidity, mortality, quality of life (QOL), and physiologic outcome, including spirometry, gas exchange, and exercise performance in 15 patients with severe emphysema and a resting PaCO2 of > 45 mm Hg (group 1), and compared the results with those from 31 patients with a PaCO2 of < 45 mm Hg (group 2). RESULTS: All preoperative physiologic and QOL indices were more impaired in the hypercapnic patients than in the eucapnic patients. The hypercapnic patients exhibited a lower preoperative FEV1, a lower diffusing capacity of the lung for carbon monoxide, a lower ratio of PaO2 to the fraction of inspired oxygen, a lower 6-min walk distance, and higher oxygen requirements. However, after surgery both groups exhibited improvements in FVC (group 1, p < 0.01; group 2, p < 0.001), FEV1 (group 1, p=0.04; group 2, p < 0.001), total lung capacity (TLC; group 1, p=0.02; group 2, p < 0.001), residual volume (RV; group 1, p=0.002; group 2, p < 0.001), RV/TLC ratio (group 1, p=0.03; group 2, p < 0.001), PaCO2 (group 1, p=0.002; group 2, p=0.02), 6-min walk distance (group 1, p=0.005; group 2, p < 0.001), oxygen consumption at peak exercise (group 1, p=0.02; group 2, p=0.02), total exercise time (group 1, p=0.02; group 2, p=0.02), and the perceived overall QOL scores (group 1, p=0.001; group 2, p < 0.001). However, because the magnitude of improvement was similar in both groups, and the hypercapnic group was more impaired, the spirometry, lung volumes, and 6-min walk distance remained significantly lower post-LVRS in the hypercapnic patients. There was no difference in mortality between the groups (p=0.9). CONCLUSIONS: Patients with moderate to severe resting hypercapnia exhibit significant improvements in spirometry, gas exchange, perceived QOL, and exercise performance after bilateral LVRS. The maximal achievable improvements in postoperative lung function are related to preoperative level of function; however, the magnitude of improvement can be expected to be similar to patients with lower resting PaCO2 levels. Patients should not be excluded from LVRS based solely on the presence of resting hypercapnia. The long-term benefit of LVRS in hypercapnic patient remains to be determined.