Intrapleural Pressure Research Articles

Equine exercise-induced pulmonary hemorrhage: the role of high left-heart pressures secondary to exercise-induced hypervolemia, and high inspiratory pressures.

Exercise-induced hypervolemia is normal in racehorses. Stress failure of the blood-gas barrier causes EIPH and occurs when the transmural pulmonary capillary (Pcap)-alveolar pressure difference (Ptm) exceeds the barrier's stress failure threshold. Why Pcap increases is incompletely understood. We hypothesized that alterations in blood volume (BV) affect left ventricular (LV) and pulmonary arterial wedge (PAW) pressures, and Pcap, and correspondingly affect EIPH severity. Six thoroughbreds with EIPH underwent treadmill exercise at the same speed (≈11.9m/s [11.1, 12.2]; median [IQR]) before (≈119%V̇O2max; B), 2hr after 14L depletion of blood (≈132%V̇O2max; D) and 2hr after reinfusing the blood (≈111%V̇O2max; R). LV, pulmonary arterial (PAP), PAW and intrapleural (Ppl) pressures were measured throughout exercise. Pcap = (PAP+PAW)/2 and Ptm = Pcap - Ppl. EIPH severity was assessed 60min post-exercise by tracheoendoscopy (EIPHgrade) and bronchoalveolar lavage erythrocyte count (BALRBC). A mixed-effect model and Tukey post-hoc test analyzed effects of BV changes on LV, PAW, Pcap, Ppl, Ptm and EIPH. p≤0.05 was significant. EIPH severity was affected by BV (EIPHgrade: p=0.01, BALRBC: p=0.003). Peak Ptm was not different between B (146mmHg [140; 151]) and R (151mmHg [137; 160]) but was lower for D (128mmHg [127; 130]; B: p=0.005, R: p=0.02). LV end diastolic pressure (LVED) was correlated with maxPcap (r2=0.52, p=0.001). Ppl was unaffected by changes in BV. Vascular pressures and Ppl fluctuated constantly during exercise and independently influenced Ptm. Circulating BV but not exercise intensity had a major effect on LVED, Pcap and Ptm, and was correlated with EIPH severity in thoroughbred racehorses (r2=0.48, p=0.001).

Assessment of Chest Tube Management Knowledge among Critical Care Nurses in a Tertiary Care Cardiac Hospital: A Descriptive Study

Objectives: Chest tubes play a critical role in managing intra-pleural pressure imbalances and preventing potentially fatal outcomes such as pulmonary collapse. The management of chest tubes is primarily the responsibility of nursing care in patients reliant on this intervention. This study aimed to assess the level of knowledge regarding chest tube management among critical care nurses at a tertiary care cardiac hospital in Karachi, Pakistan. Methodology: This descriptive cross-sectional study utilized a convenient sampling method, involving a sample size of n=120 participants. Data collection involved a structured questionnaire comprising demographic parameters followed by an 18-item questionnaire assessing knowledge of chest tube management. Knowledge scores were calculated as the percentage of correct responses to the 18 knowledge-related questions. Results: Among the 120 nurses surveyed, 59.2% (71) were male, 55% (66) were under 36 years of age, and 66.7% (80) had up to 10 years of work experience. Only 20% (24) had participated in training courses regarding thoracic diseases. The mean knowledge score was 57.3 ± 17.2, with 30% (36) categorized as having low knowledge (<50%), 65% (78) as moderate knowledge (50% to 80%), and 5% (6) as high knowledge (>80%). Conclusion: The study revealed a moderate level of knowledge concerning chest tube management among critical care nurses in a tertiary care cardiac center. There is a need for structured and comprehensive training programs focusing specifically on chest tube management to enhance nurses proficiency in this critical area of patient care.

Hybrid (Digital/Water Seal) Chest Drainage System - An Innovative Device for Patients with Anticipated Air Leaks.

To date, several chest drainage systems are available, such as digital drainage systems (DDS) and traditional systems with continuous suction or water seal. However, none of these systems were yet shown to be favorable in the treatment of complex situations such as persistent air leaks or residual spaces. We present in-vitro as well as clinical data of a novel hybrid drainage system consisting of an optimized digital drainage system (ODDS) and an underwater seal drainage system (UWSD). For in-vitro analysis, a DDS and an ODDS were connected to a pleural cavity simulator. Different air leaks were produced and data on intrapleural pressure and air flow were analyzed. Furthermore, we tested the hybrid drainage system in 10 patients with potential air leaks after pulmonary surgery. In in-vitro analysis, we could show, that with advanced pump technology, pressure fluctuations caused by the drainage system when trying to maintain a set pressure level in patients with airleaks were much smaller when using an ODDS and could even be eliminated when using a fluid collection canister with sufficient buffer capacity. This minimized air leak boosts caused by the drainage system. Optimizing the auto-pressure regulation algorithms also led to a reduced airflow through the fistula and promoted rest. Switching to a passive UWSD also reduced the amount of airflow. Clinical application of the hybrid drainage system yielded promising results. The novel hybrid drainage system shows promising results in the treatment of patients with complex clinical situations such as persistent air leaks.

Development of a multivariable prediction model for prolonged air leak after lung resection.

Prolonged air leak (PAL) is a common complication of lung resection. Research on predictors of PAL using a digital drainage system (DDS) remains insufficient. In this study, we investigated the predictive factors of PAL to establish a novel early postoperative prediction model for PAL. A retrospective cohort study and validation study were conducted. We examined patients who underwent lung resection with DDS at our institute. The relationship between the clinical factors and measurements of the DDS, including the difference between the set and measured intrapleural pressure (named: additional negative pressure [ANP]) at postoperative hour (POH) 3, with PAL was analyzed. A total of 494 patients were enrolled, 29 of whom had PAL. Percent forced expiratory volume in 1s<60%, ANP <1cmH2O, air leak flow >20mL/min and pleural adhesion findings at surgery were independent predictors of PAL according to a multivariable analysis. The PAL rate was clearly stratified according to our novel risk scoring system, which simply notes the presence of the above four factors, that is, the rate increases when the score increases. The area under the curve (AUC) of the receiver operating characteristic (ROC) analysis for this scoring system was 0.818. Analysis of the validation cohort (n=133) revealed that this scoring system showed a sufficient ability to predict PAL. ANP at POH 3 is an independent predictor of PAL. Thus, the risk-scoring system proposed in this study is useful for predicting PAL in the early postoperative period.

Re-expansion Pulmonary Edema

Re-expansion pulmonary edema (RPE) is a rare complication of pleural puncture (thoracentesis) and chest tube insertion. The incidence of RPE is low (1%), but mortality can be up to 20%. The main pathophysiological mechanism is pulmonary edema due to increased permeability and increased hydrostatic pressure in the pulmonary capillaries. Risk factors include duration of lung collapse (&gt;3 to 7 days), size of pneumothorax (&gt;30%), volume of aspirated air or fluid (&gt;1.5 to 3 L), excessive negative intrapleural pressure, diabetes mellitus, and chronic hypoxemia. Prevention includes limiting the volume of aspirated air or fluid (&lt;1.5 L), air or fluid evacuation in a controlled manner, and preventing excessive negative intrapleural pressure. Treatment is supportive care through cardiovascular and respiratory monitoring, oxygen and decubitus positioning.

Respiratory patterns in spontaneously breathing near-term lambs delivered by caesarean section under spinal anaesthesia.

The transition to newborn life has typically been studied in intubated and mechanically ventilated newborn lambs delivered via caesarean section (CS) under general anaesthesia. As a result, little is known of the spontaneous breathing patterns in lambs at birth, particularly those at risk of developing respiratory distress (RD). We have developed a method for delivering spontaneously breathing near-term lambs to characterise their breathing patterns in the immediate newborn period. At 137-8 days gestation (2-3 days prior to delivery; term ∼147 days), fetal lambs (n = 7) were partially exteriorised for instrumentation (insertion of catheters and flow probes) before they were returned to the uterus. At 140 days, lambs were delivered via CS under light maternal sedation and spinal anaesthesia. Lambs were physically stimulated and when continuous breathing was established, the umbilical cord was clamped. Breathing patterns were assessed by measuring intrapleural and upper-tracheal pressures during the first four hours after birth. Newborn lambs display significant heterogeneity in respiratory patterns in the immediate newborn period that change with time after birth. Seven distinct breathing patterns were identified including: (i) quiet (tidal) breathing, (ii) breathing during active periods, (iii) breathing during oral feeding, (iv) tachypnoea, (v) expiratory braking manoeuvres, (vi) expiratory pauses or holding, and (vii) step changes in ventilation. We have described normal respiratory behaviour in newborn lambs, in order to identify respiratory behaviours that are indicative of RD in term newborn infants.

Distribution of transpulmonary pressure during one-lung ventilation in pigs at different body positions.

Background. Global and regional transpulmonary pressure (PL) during one-lung ventilation (OLV) is poorly characterized. We hypothesized that global and regional PL and driving PL (ΔPL) increase during protective low tidal volume OLV compared to two-lung ventilation (TLV), and vary with body position. Methods. In sixteen anesthetized juvenile pigs, intra-pleural pressure sensors were placed in ventral, dorsal, and caudal zones of the left hemithorax by video-assisted thoracoscopy. A right thoracotomy was performed and lipopolysaccharide administered intravenously to mimic the inflammatory response due to thoracic surgery. Animals were ventilated in a volume-controlled mode with a tidal volume (VT) of 6mLkg-1 during TLV and of 5mLkg-1 during OLV and a positive end-expiratory pressure (PEEP) of 5 cmH2O. Global and local transpulmonary pressures were calculated. Lung instability was defined as end-expiratory PL<2.9 cmH2O according to previous investigations. Variables were acquired during TLV (TLVsupine), left lung ventilation in supine (OLVsupine), semilateral (OLVsemilateral), lateral (OLVlateral) and prone (OLVprone) positions randomized according to Latin-square sequence. Effects of position were tested using repeated measures ANOVA. Results. End-expiratory PL and ΔPL were higher during OLVsupine than TLVsupine. During OLV, regional end-inspiratory PL and ΔPL did not differ significantly among body positions. Yet, end-expiratory PL was lower in semilateral (ventral: 4.8 ± 2.9 cmH2O; caudal: 3.1 ± 2.6 cmH2O) and lateral (ventral: 1.9 ± 3.3 cmH2O; caudal: 2.7 ± 1.7 cmH2O) compared to supine (ventral: 4.8 ± 2.9 cmH2O; caudal: 3.1 ± 2.6 cmH2O) and prone position (ventral: 1.7 ± 2.5 cmH2O; caudal: 3.3 ± 1.6 cmH2O), mainly in ventral (p ≤ 0.001) and caudal (p = 0.007) regions. Lung instability was detected more often in semilateral (26 out of 48 measurements; p = 0.012) and lateral (29 out of 48 measurements, p < 0.001) as compared to supine position (15 out of 48 measurements), and more often in lateral as compared to prone position (19 out of 48 measurements, p = 0.027). Conclusion. Compared to TLV, OLV increased lung stress. Body position did not affect stress of the ventilated lung during OLV, but lung stability was lowest in semilateral and lateral decubitus position.

C11 LARGE PLEURAL AND PERICARDIAL EFFUSION: WHICH DRAIN FIRST?

Abstract Introduction Large pleural and pericardial effusion is a common finding in lung cancer patients. However, a chronic large pleural effusion and the “lung entrapment” fenomenon, due to the neoplastic lung infiltration, could precipitate the re–expansion pulmonary edema (REPO) after the thoracentesis procedure. REPO is a rare and potentially life–threatening complication after large volume thoracentesis. It is characterized by alveolar infiltration in the reexpanded lung.Indeed, in the presence of “lung entrapment”, REPO development could be due not only to and excessive fluid removal, but also to the development of an excessively negative intrapleural pressure (&amp;lt; – 20 mmHg). As the REPO is often associated to an hemodynamic impairment, in patients with concomitant severe pericardial effusion, this condition could cause cardiac tamponade and the optimal therapeutic approach could be challenging.In this perspective, the decision on the effusion to be drained first, in this population, is not always straightforward.Case report In a 62 years –old woman with severe respiratory failure, a chest CT scan showed a massive left –sided pleural effusion with a complete collapse of the left lung, a severe pericardial effusion (35 mm) and the presence of malignant mediastinal nodes. (Figure 1).In the ICU a left thoracentesis was performed, with an early drainage of 1400 ml, the drain was then clamped. 30 minutes later, the patient developed a severe acute respiratory failure. An urgent chest x ray revealed an ipsilateral pulmonary oedema (Figure2). The patient was then treated with respiratory support with cPAP and intravenous diuretic therapy. Afterward, a rapid hemodynamic derangement occurred, with cardiac tamponade. An emergency echoguided pericardiocentesis was then performed followed by an immediate recovery. A repeated thorax CT scan revealed an advanced pulmonary tumor (Figure 3). Discussion In this case all the risk factors for REPO were coexistent: chronic pleural effusion and lung cancer. In addition, the large pericardial effusion represented a complicating factor in this situation as both the cPAP and the REPO’s hypovolemia may have brought to a clinical tamponade. In this context, where a neoplastic severe pleural and pericardial effusions are coexistent, it is essential to know which possible complications may occur after a large volume thoracentesis in order to prevent a high risk urgent pericardial drainage in patient with severe respiratory distress.

Negative Pressure Pneumomediastinum: A Novel Concept of Spontaneous Pneumomediastinum Without Mediastinal Widening Following Weight Loss.

Spontaneous pneumomediastinum, supposedly attributed to air leakage from the respiratory tract, is a common complication of interstitial lung disease often resulting in mediastinal widening. However, several cases of pneumomediastinum without mediastinal widening have been observed. This study aimed to investigate the cause of pneumomediastinum in patients without mediastinal widening. This study included 41 patients diagnosed with pneumomediastinum using computed tomography (CT) between July 2011 and September 2021 at Yokohama Minamikyosai Hospital; patients had undergone previous CT showing no gas density. Based on a comparison with previous CT images, the patients were classified into two groups: without mediastinal widening and with mediastinal widening. Of the 41 patients, 13 and 28 had pneumomediastinum without and with mediastinal widening, respectively. There were no significant differences in the sex, age, body mass index, or pneumomediastinum distribution between the groups. However, the rate of weight loss per month was significantly greater in the group without mediastinal widening than in that with mediastinal widening. No significant differences were observed in the respiratory function test results between the two groups; that said, 10 of the 13 patients without mediastinal widening had restrictive disorders. Pulmonary disease in this group included idiopathic pulmonary fibrosis (n = 6), interstitial lung disease with collagen disease (n = 4), and other disease (n = 1). Pneumomediastinum occurred during periods of weight loss in all patients without widening, excluding two patients without data. Pneumomediastinum without mediastinal widening occurs during rapid weight loss and is often associated with restrictive lung disorders. The negative pressure attributed to the decreased plasticity of the lungs, which complements the space where the mediastinal fat has disappeared, is presumably the cause of pneumomediastinum. This pathophysiology is different from that of conventional pneumomediastinum attributed to increased intrapleural space pressure; thus, we propose to name the abovementioned pathophysiology "negative pressure pneumomediastinum".

Misconnected chest tube: An extremely unusual fatal complication of secondary pneumothorax.

A rare and fatal complication of suction drainage of secondary spontaneous pneumothorax is reported. The patient, likely by a mistake, arbitrarily connected the oxygen supply tube to the thoracic drain. The sharp increase of intrapleural pressure combined with the atmospheric intraalveolar environment caused diffuse lung injury and cardiopulmonary collapse without a direct lung injury. The conflicting interests of patient autonomy and patient safety require further consideration.

Trapped lung: a review of literature and recent cases

A trapped lung, one that cannot expand due to a restrictive fibrous visceral pleural peel, is caused by malignancy, chest trauma, thoracic surgery, complicated infection, and autoimmune conditions. Suspicion for and evaluation of this condition should be considered early on in a patient with history of the above conditions that presents with a chronic pleural effusion of stable volume. Diagnosis is reached with pleural fluid analysis, manometry that shows negative intrapleural pressure that is further reduced with fluid aspiration, and imaging that shows a chronic effusion and pleural thickening. Treatment is dependent on symptomatology and overall patient condition, and ranges from observation to fluid removal, fibrinolytic therapy, talc pleurodesis, indwelling pleural catheter, and surgical decortication. A review of English literature from the last 10 years including case reports, case series, and observational reviews was conducted. A majority of these patients presented with trapped lung due to malignancy, infection, or autoimmune conditions. Treatment varied depending on the cause of the trapped lung, underlying conditions, and patient preference; a majority of these patients received either pleurodesis, intrapleural fibrinolytic therapy, or surgical decortication.

Negative-pressure pulmonary edema and alveolar hemorrhage are potentially life-threatening complications of upper airway obstruction

Negative pressure pulmonary edema and alveolar hemorrhage are potentially life-threatening complications after relief of upper airway obstruction. The laryngeal-pharyngeal obstruction results in high negative intrapleural pressures. The increased intrapleural pressures affect the integrity of the alveolo-capillary membrane due to various factors. This review describes clinical symptoms, etiologic factors, pathophysiology and treatment strategies associated with each of these factors. The aim of this review is to equip clinicians with the knowledge base necessary to identify patients at increased risk for negative pressure pulmonary edema and alveolar hemorrhage.

The effects of chest drainage on pressure-controlled ventilation

BackgroundThe use of pressure-controlled ventilation (PCV) for anesthesia management is becoming more commonly used. Chest drainage is commonly performed after thoracic surgery, and the negative pressure it generates might affect the transpulmonary pressure (TPP). In the present study, we investigated how chest drainage could affect ventilating conditions during PCV.MethodsWe created a hand-made simple thoracic and lung model, which was connected to an anesthesia machine. The tidal volume (TV) was measured with positive end-expiratory pressure (PEEP) 0 and no chest drainage (baseline), followed by 10 cmH2O PEEP/no drainage, 10 cmH2O PEEP/drainage with − 10 cmH2O and 10 cmH2O PEEP/drainage with − 20 cmH2O. Finally, TV with 20 cmH2O and 30 cmH2O PEEP/no drainage was measured. Driving (inspiratory) pressure was maintained at 20 cmH2O during the whole experiment.ResultsTV was significantly increased by applying 10 cmH2O PEEP compared with baseline, further increased by applying − 10 cmH2O by drainage, similar to the value with PEEP 20 cmH2O with no drainage (end-tidal TPP of 20 cmH2O for both). TV decreased to < 50% of the baseline by applying 10 cmH2O PEEP with − 20 cmH2O by drainage, which was similar to that with 30 cmH2O PEEP with no drainage (end-tidal TPP of 30 cmH2O for both).ConclusionsTV was maintained at similar levels with the same TPP, regardless of PEEP or negative pressure by chest drainage change, suggesting that negative intrapleural pressure by the chest tube drainage system might mimic PEEP from the point of TV.

ABDOMINAL COMPRESSION IN END-STAGE FIBROTIC INTERSTITIAL LUNG DISEASE (ILD) IMPROVES RESPIRATORY COMPLIANCE

ABDOMINAL COMPRESSION IN END-STAGE FIBROTIC INTERSTITIAL LUNG DISEASE (ILD) IMPROVES RESPIRATORY COMPLIANCE

Intratidal compliance of the lung and the total respiratory system

Objective. The worldwide rising quantity of surgeries and the corresponding need of mechanical ventilation means a rising number of patients are at risk of suffering from post-operative pulmonary complications. To prevent this risk, individual mechanics of the lung should be considered when setting the parameters of mechanical ventilation. Intratidal compliance analysis based on transpulmonal pressure would provide an estimate for individual lung mechanics. The downside of such measure, however, is its invasiveness. Accurate measurement requires recording of the esophageal pressure as surrogate for the actual pleural pressure. Measuring pressure at the airway opening is considerably easier, but the resulting mechanics of the respiratory system may not represent the actual lung mechanics in a straightforward fashion. Approach. In order to evaluate if the mechanics of the lungs are represented by analysis of the mechanics of the respiratory system we determined intratidal dynamic compliance-volume profiles of both in 23 lung-healthy mechanically ventilated patients undergoing elective surgery. We also compared the accuracy of the compliance profiles resulting from analysis of the total breath with those resulting from the analysis of inspiration data only. Main results. When the whole breath was analyzed 54.3%, and with only inspiration data 69.6%, of compliance profiles of the respiratory system matched those of the lung. With both approaches profiles of the lung and the respiratory system matched or deviated by only one neighboring step (75% whole breath, 91.3% inspiration only), and never contradicted each other. Significance. Compliance profiles calculated from volume and pressure data of the respiratory system are an adequate surrogate for the compliance profiles of the lungs of lung-healthy patients. Therefore, invasive assessment of esophageal pressure for achievement of intrapleural pressure is unnecessary. The compliance profiles based on only inspiratory data appear more sensitive for indicating intratidal derecruitment than those based on data of the whole breath.

Effects of combined one-lung ventilation and intrathoracic carbon dioxide insufflation on intrathoracic working space when performing thoracoscopy in dogs.

To evaluate the effects of combining one-lung ventilation and carbon dioxide insufflation (OLV-CDI) on intrathoracic working space (determined by means of CT) during thoracoscopy in dogs and investigate conditions that could safely improve working space compared with OLV alone. 6 healthy Beagles. Dogs were anesthetized, and right- or left-sided (n = 3/side) OLV was instituted. On the blocked side, a laparoscopic trocar sleeve was placed in the ninth intercostal space for CDI. CT was performed under 3 conditions: with OLV alone, with OLV-CDI at an intrapleural pressure (IPP) of 3 mm Hg, and with OLV-CDI at an IPP of 5 mm Hg. Working space volume (WSV), ventilation space volume (VSV), and thoracic cavity volume (TCV) were determined from CT images. With OLV-CDI at an IPP of 3 or 5 mm Hg, WSV and TCV were significantly increased, compared with values obtained during OLV alone. With OLV-CDI at an IPP of 5 mm Hg, VSV and Spo2 were significantly decreased, compared with values obtained during OLV alone. Additionally, contralateral pneumothorax was observed in 4 dogs at an IPP of 5 mm Hg. Combining OLV and CDI could provide a larger working space than OLV alone, even with an IPP of 3 mm Hg, in dogs of limited size. However, an evaluation of the effects on oxygenation and cardiovascular variables is needed before clinical use.

Experimentally-guided development of a sensor for pleural cavity pressure sensing.

The precise monitoring of the intrapleural pressures, necessitates the development of a specific instrumental approach to select the correct shape, dimensions and material to implement the sensing balloon which will be inserted into the pleural cavity. We demonstrate that a 10 cm diameter disk, printed with filaments of TPU (Thermoplastic polyurethane) with hardness 92A offers the best compromise in terms of static sensitivity (0.28 mV/cmHg) and dynamic frequency response (48 Hz).

Non-invasive cardiac output monitoring before and after baby extubation – A feasibility study (NICOMBabe study)

BackgroundMechanical ventilation induces changes in intrapleural, intrathoracic and intra-abdominal pressure. These changes have various implications on cardiac output (CO). AimsThe aim of this study was to determine the feasibility of measuring changes in CO after elective extubation in neonates using the principle of transthoracic bioreactance (TBR). Study designThis was a prospective observational cohort study in a level III neonatal centre. CO, stroke volume (SV) and heart rate were measured continuously for 2 h before and 2 h after elective extubation by TBR. SubjectsNeonates undergoing elective extubation were eligible for enrolment. Outcome measuresThe primary outcome of the study was change in CO post elective extubation. ResultsTen neonates were enrolled, seven (70 %) had a statistically significant decrease in CO after extubation, three (30 %) infants had a statistically significant increase in CO after extubation. Changes in CO were primarily driven by changes in SV and the pattern of change was related to patent ductus arteriosus (PDA) status prior to extubation. ConclusionExtubation significantly influences CO in neonatal patients and the pattern of change appears to be related to PDA status.

Safety and efficacy of vacuum bottle plus catheter for drainage of iatrogenic pneumothorax

BackgroundIatrogenic pneumothorax is common after thoracic procedures. For patients with pneumothorax larger than 15%, simple aspiration is suggested. Although vacuum bottle plus non-tunneled catheter drainage has been performed in many institutions, its safety and efficacy remain to be assessed.MethodsThrough this prospective cohort study (NCT03724721), we evaluated the safety and efficacy of vacuum bottle plus non-tunneled catheter drainage. Patients older than 20 years old who developed post-procedural pneumothorax were enrolled. A non-tunneled catheter was placed at the intersection of the midclavicular line and the second intercostal space. A 3-way stopcock, a drainage set, and a digital pressure gauge were connected. The stopcock was manipulated to connect the pleural space to the pressure gauge for measurement of end-expiration intrapleural pressure or to the vacuum bottle for air drainage. The rate of successful drainage, the end-expiration intrapleural pressure before, during, and after the procedure and the duration of hospitalization were recorded.ResultsFrom August 2018 to February 2020, 21 patients underwent vacuum bottle plus catheter drainage (intervention group) and 31 patients received conservative treatment (control group). The end-expiration intrapleural pressure of all patients remained less than − 20 cmH2O during drainage. No procedure related complication was observed. Large pneumothorax (≥ 15%) was associated with higher risk of persistent air leak (Odds ratio 12, 95% CI 1.2–569.7). Vacuum bottle assisted air drainage yielded shorter event-free duration than that of conservative treatment (2 days vs 5 days [interquartile range 1–4 days vs 3–7 days], p < .05). Vacuum bottle assisted air drainage also help identifying patients with persistent pneumothorax and necessitate the subsequent management. The event-free duration of persistent air leak in the intervention group was also comparable with that of conservative treatment (5 days vs 5 days [interquartile range 5–8 days vs 3–7 days], p = .45).ConclusionsVacuum bottle plus catheter drainage of iatrogenic pneumothorax is a safe and efficient procedure. It may be considered as an alternative management of stable post-procedural pneumothorax with size larger than 15%.Trial registration The study protocol was approved by the Research Ethics Committee of National Taiwan University Hospital (No. 201805105DINA) on 6th August, 2018. The first participant was enrolled on 23rd August, 2018 after Research Ethics Committee approval. This clinical trial complete registration at U.S. National Library of Medicine clinicaltrials.gov with identifier NCT03724721 and URL: https://clinicaltrials.gov/ct2/show/NCT03724721 on 30th October, 2018.

A case requiring re-thoracotomy due to a significant reduction of tidal volume after commencement of chest tube drainage under pressure control ventilation following lower lobectomy

BackgroundThe use of pressure-controlled ventilation (PCV) during one lung ventilation (OLV) has been popular to avoid high airway pressure. We experienced a case of a significant reduction of tidal volume (TV) after commencement of chest tube drainage under PCV following lower lobectomy, which required re-thoracotomy to evaluate the degree of air leak.Case presentationA 70-year-old man was scheduled for a lower lobectomy. OLV was managed by PCV. The driving pressure was set at 15–20 cmH2O with 4 cmH2O of positive end-expiratory pressure (PEEP). A chest drainage tube was placed after completion of lobectomy. To switch OLV to two lung ventilation (TLV), PCV settings were changed to the driving pressure at 10 cmH2O with 4 cmH2O of PEEP, which generated 450 ml of TV. Immediately after applying drainage (−10 cmH2O), TV decreased down to 250 ml. To maintain 450 ml of TV, PCV was switched to volume-controlled ventilation with 450 ml of TV, which raised the plateau pressure close to 24 cmH2O. Re-thoracotomy was done; however, significant findings were not detected.ConclusionsWe experienced a case of a significant reduction of TV immediately after chest tube drainage following lower lobectomy. Probably, negative intrapleural pressure increased the residual volume, which might have significantly affected the limited lung volume after lobectomy, resulting in decreasing TV during PCV.