Underwater Seal Research Articles

Management of empyema - Role of a surgeon

Postpneumonic empyema still remains quite common in developing countries, especially during the hot and humid months. While most cases would respond to antibiotic therapy, needle aspiration and intercostal drainage, few cases require further surgical management.<br>The most common nontubercular etiological agent is Staphylococcus. Tubercular etiology is not uncommon in India, especially due to delayed presentation, multiresistant strains, mismanaged cases, and noncompliance with antitubercular treatment amidst malnutrition and anemia. Clinical symptoms, a skiagram chest followed by thoracentesis are enough for diagnosis. Pleural fluid is usually diagnostic and helps in choosing the appropriate antibiotics. Further investigations and management depends on the stage of the disease. Thoracentesis alone may be sufficient for the exudative phase. In fibrinopurulent stage, a properly sized and well-placed tube thoracostomy with underwater seal is curative in most cases. Interventional radiologists have placed small-bore catheters, specifically directed to the loculated collection and have used fibrinolytics like urokinase, streptokinase, and tissue plasminogen activator (TPA) to break loculations, ameliorate fibrous peel formation, and fibrin deposition.<br>Thoracoscopic debridement and thoracoscopic decortication is an alternative with distinct advantages over thoracotmy and are indicated if there was no response with intercostal drainage procedure. In the organizing stage, a thoracotomy (for decortication) would be required if there is a loculated empyema, underlying lung disease or persistently symptomatic effusions. Timely institution of proper management prevents the need for any surgical intervention and avoids long-term morbid complications.<br>

High-vacuum drains rival conventional underwater-seal drains after pediatric heart surgery

The collection of fluid in the mediastinum after cardiac surgery is traditionally prevented using underwater seal drains that may be connected to low-pressure suction. High-vacuum drains (redivac drains) are a potential alternative to this arrangement and have previously been utilized in areas of general surgery, as well as in the treatment of post-sternotomy mediastinitis. There has been no study to date addressing the safety and efficacy of these drains following pediatric cardiac surgery. Five hundred and forty-six patients were prospectively randomised to receive either the redivac drains or the conventional underwater-seal drains attached to low-pressure wall suction. We sought to test the null hypothesis that there was no difference in the incidence of residual pericardial or pleural collections requiring drainage between the 2 drainage systems. Secondary endpoints included time to drain removal, volume of drainage and drain size. Analysis was performed on an intention to treat basis. Two hundred and thirty-seven patients were allocated to the redivac group, while 241 were allocated to the conventional drain group. Age and gender distribution, the use of cardiopulmonary bypass, numbers of patients with univentricular morphology and number of drains utilized were similar in the 2 groups. The use of redivac drains resulted in a significantly lower incidence of residual pleural effusions requiring drainage (4 vs. 18, P=0.003). There was no difference in the incidence of pericardial effusion requiring drainage. Redivac drains drained an equivalent volume through smaller calibre tubes (12 Ch vs. 16 Ch, P<0.0001) over a shorter period of time (42h (IQR 22-45) vs. 43h (IQR 27-52), P<0.01) than the conventional drainage system. Redivac drains are as safe and effective as conventional drains in the pediatric setting, and resulted in a lower incidence of residual pleural effusions requiring drainage. Together with their ease of care, earlier mobilisation of patients and greater cost-effectiveness, the routine use of high-vacuum drains can be recommended following pediatric heart surgery.

A Prospective, Randomized Trial of Underwater Seal for Spontaneous and Iatrogenic Pneumothorax

A Prospective, Randomized Trial of Underwater Seal for Spontaneous and Iatrogenic Pneumothorax

Higher risk of complications with underwater seal drains

Higher risk of complications with underwater seal drains

A comparison of the continuous positive airway pressures produced by two systems

To compare the generation of continuous positive airway pressure using a hand-made device (underwater seal) or a ventilator (Inter 3). Two positive airway pressure generation systems were compared through laboratory simulations. Measurements were not considered if the mechanical ventilator required calibration or in the presence of gas flow variation (flowmeter sphere oscillation). Recordings were assessed in terms of the capacity to produce the desired pressure (3, 5 and 6 cmH2O) when submitted to three different flow values (8, 10 and 12 l/min). For that end, Student's t test for paired samples and the nonparametric Man-Whitney test for independent samples were employed. We verified that the systems behave in different manners under the same conditions of flow and positive end expiratory pressure. For the mechanical ventilator, the mean pressure behavior under continuous positive airway pressure at 3 cmH2O with flows of 8, 10 and 12 l/min were 2.26+/-0.41, 2.22+/-0.37, 2.04+/-0.41, respectively; under positive end-expiratory pressure at 5 cmH2O we found 3.96+/-0.41, 3.87+/-0.43 and 3.75+/-0.52; and under positive end-expiratory pressure at 6 cmH2O the values recorded were 4.94+/-0.40, 4.85+/-0.41 and 4.72+/-0.37. For the underwater seal, the mean pressure behavior under continuous positive airway pressure at 3 cmH2O with flows of 8, 10 and 12 l/min were 4.24+/-0.24, 4.46+/-0.26, 4.72+/-0.37, respectively; at 5 cmH2O the values were 5.97+/-0.17, 6.28+/-0.18, 6.47+/-0.31; and at 6 cmH2O we recorded 6.85+/-0.20, 7.17+/-0.29 and 7.53+/-0.31. All the comparisons were statistically significant (p = 0.000). Through our recordings it was possible to observe that the Inter 3 continuous positive airway pressure system was more stable than the underwater seal.

Combined endovascular and video-assisted thoracoscopic procedure for treatment of a ruptured pulmonary arteriovenous fistula: case report and review of the literature

A35-year-old woman with a medical history of hereditary and recurrent epistaxis and lip telangiectasia was admitted with sudden left thoracic pain and dyspnea. There was no recent history of fever or thoracic trauma. Biologic data were as follows: hemoglobin level, 8.8 g/L; hematocrit level, 28%; oxygen saturation, 97%; and fraction of inspired oxygen, 10 L/min. Chest radiography and computed tomographic (CT) scanning revealed a left hemothorax with a suspicion of a vascular malformation in the left lower lobe (Figure 1). There were no aortic or pericardial abnormalities. An intercostal drain was placed in the left pleural cavity, and 2000 mL of blood was drained, leading to a significant clinical improvement. Pulmonary angiography confirmed the presence of 2 arteriovenous fistulas in the upper part of the left lower lung and in the lingula (Figure 2). Rendu-Osler-Weber syndrome (ROW) was diagnosed on the basis of the patient’s history and clinical and radiologic data. Embolization of the lower lobe fistula was performed during general anesthesia with 3 Guglielmi Detachable Coils (Boston Scientific, Target Therapeutics, Fremont, Calif). One 3-dimensional shaped coil of 8 20 mm and 2 fibered coils of 6 20 mm and 4 20 mm, respectively, were placed with a 0.018-inch microcatheter (Boston Scientific, Target Therapeutics) in the feeding artery. Occlusion was completed with the injection of 0.3 mL of enbucrilate (Histoacryl; Braun Aesculap, Tuttlingen, Germany) emulsified with iodized oil (Lipiodol; Guerbet, Aulnay-sous-Bois, France). Catheterization of the lingula fistula was technically more difficult, and occlusion was achieved with a 4 20–mm fibered spiral placed with a 0.018-inch microcatheter (Boston Scientific; Figure 3). Immediately after the endovascular procedure, video-assisted thoracoscopic surgery was performed to remove any residual clot and exclude further bleeding. The patient was placed in the right decubitus position. A single-lumen endotracheal tube was inserted, and ventilation was performed with reduced tidal volume throughout the procedure. A 10-mm trocar was introduced through a skin incision into the fifth intercostal space in the midaxillary line for insertion of a 0° endoscope (Karl Storz, Tuttlingen, Germany). Numerous clots and a large hemothorax in the left thoracic cavity were observed. Two additional ports were then inserted under direct vision. After the entire thoracic cavity had been rinsed with saline and clots had been removed, pulmonary arteriovenous fistulas were visible on the surface of the lung (Figure 4). No active bleeding was observed, and no further operations were required. Two 28F chest drains were introduced through the trocar incisions, one in the eighth and one in the anterior fifth intercostal spaces. The tubes were connected to an underwater seal suction device (Pleurevac; Genzime, Cergy-Pontoise, France) with a negative pressure of 20 cm H2O. The patient was extubated 3 hours after the operation, and pain was managed with a patient-controlled analgesia pump. Intercostal drainage was continued for 4 days, with a total volume of 975 mL. No air leak was observed, and the postoperative hospital stay was 6 days. Follow-up angiography at 1 month and CT scanning at 3 months revealed recurrent limited flow in the lingula fistula (Figure 5). Repeat embolization was performed with 2 coils (1 fibered coil of 2 50 mm and 1 coil of 2 30 mm) placed with a 0.018-inch microcatheter (Boston Scientific). The occlusion was completed without injection of enbucrilate. Follow-up CT scans at 3 months and 2 years showed no recurrence.

Bilateral pneumothorax complicating miliary tuberculosis in children: case report and review of the literature

An 11-year-old boy presented with a 4-week history of fever and 2 weeks later developed a cough with breathlessness. His chest X-ray showed bilateral miliary shadows with pneumothorax on the left side. While on antituberculous therapy which was started on admission, he developed right-sided pneumothorax with significant collapse of the left lung. He was managed by tube thoracotomy with underwater seal but died 4 hours after the procedure was completed.

Underwater calling rates of harp and Weddell seals as a function of hydrophone location

Stereo recordings of harp seal (Pagophilus groenlandicus) and Weddell seal (Leptonychotes weddellii) underwater vocalizations were made near breeding groups using separations between two hydrophones of 159–339 m. Within a large herd, harp seal call numbers varied slightly between channels. Counts of Weddell seal calls were higher near a small herd on the ice than 159–180 m away. Repeat counts of harp seal calls by a single observer differed significantly. Source levels of Weddell seal calls varied and higher amplitude calls would be detected up to 2 orders of magnitude farther away than quieter calls. Hydrophone location (especially near small groups), observer variability and call source level differences will bias the use of monitoring underwater seal vocalizations to index locations, population size or underwater behaviours. Using hydrophone arrays and multiple observers may mitigate these problems.

Estudio comparativo de distintos métodos de drenaje pleural en un modelo experimental de neumotórax

To observe the usefulness of several procedures for draining pneumothorax in an animal model and to identify the best pleural drainage system with minimal impairment of respiratory function. Thirty-four New Zealand white rabbits weighting 1687 +/- 78 g and aged a mean 59 days were randomly placed in groups as follows. Unilateral pneumothorax was induced in the first problem group (P1) rabbits (n = 10) by thoracostomy, with pleural drainage. In the second problem group (P2) of rabbits (n = 10), bilateral pneumothorax was similarly induced by thoracostomy with pleural drainage. The control groups underwent unilateral (C1; n = 7) and bilateral (C2; n = 7) thoracostomy and drainage. Every 7 minutes the chest tube was connected successfully in each animal to an underwater seal with a dead-space volume of 35.58 ml (neonatal Bülau unit) or to a 3,940 ml system (chest drainage unit) and to pleural aspirations of -5 and -20 cmH2O. We analyzed mortality, fluctuations of the hydrostatic column of the underwater seal, heart rate (HR), respiratory rate (RR), PaCO2, SaO2, pH and arterial blood gas measures. Intraoperative mortality was significantly higher (particularly in the P2 group) when connection was to a large volume system without aspiration. Recovery after pneumothorax was more satisfactory with aspiration of -5 and -20 cmH2O. The results suggest that a pleural drainage unit with a large dead space between the pleural cavity and the underwater seal is a frequent cause of respiratory failure or insufficiency. We believe that when an underwater seal without pleural suction is applied, the Bülau unit should be used with the smallest possible volume.

Tactical Management of Urban Warfare Casualties in Special Operations

CAPT Frank K. Butler CAPT Butler is a Navy ophthalmologist and diving medical officer. For the past 10 years, he has been the Director of Biomedical Research for the Naval Special Warfare Command. CAFT Butler has served previously as a platoon commander in the Navy Underwater Demolition and SEAL (Sea/Air/Land commando) teams. He also spent 5 years as a Diving Medical Research officer at the Navy Experimental Diving Unit. CAPT Butler was the Chief of Ophthalmology at the Naval Hospital Pensacola before assuming his current duties at the Naval Special Warfare Command. He also serves as an ophthalmic consultant to the Divers Alert Network.

Patients' experiences of having an underwater seal chest drain: a replication study.

The nursing management of patients who have a chest drain in situ has received little attention. The findings of a single small-scale study previously indicated that such patients' needs for information are not always fully met and pain control is inadequate. This small-scale study was replicated to produce broadly similar findings in a second hospital 2 years later. Despite some differences in the approach to management it was apparent that patients were still not well prepared pre-operatively and there was scope for improving pain control. All the patients reported considerable discomfort and pain of moderate to severe intensity. The type of pain described is typical of deep somatic/visceral pain.

Perforation of the right ventricle by a suction drain

Suction drains can be used as alternatives to conventional underwater seal drains following cardiac surgery, and may be advantageous under some circumstances. The authors present a case where a suction drain eroded into the right ventricle causing near-fatal haemorrhage following coronary artery surgery. Caution should be exercised in taking the decision to use suction drains, the material from which they are manufactured should be chosen carefully, and close attention paid to their positioning within the mediastinum.

A 16-Year-Old With Left-sided Pneumothorax

A 16-year-old boy with features of Marfan's syndrome, previously in good health, had left sided chest pain and dyspnea of 6 days' duration, which had worsened considerably on the day of admission. A posteroanterior chest radiograph showed complete pneumothorax on the left side and a partial pneumothorax on the right side. A chest tube was inserted on the left side and connected to an underwater seal drain. The patient became more dyspneic immediately. A repeat chest radiograph showed air space shadowing over the entire left lung field and an increase in the size of the pneumothorax on the right side (Fig 1) .

Perforation of the Right Ventricle by a Suction Drain

Suction drains can be used as alternatives to conventional underwater seal drains following cardiac surgery, and may be advantageous under some circumstances. The authors present a case where a suction drain eroded into the right ventricle causing near-fatal haemorrhage following coronary artery surgery. Caution should be exercised in taking the decision to use suction drains, the material from which they are manufactured should be chosen carefully, and close attention paid to their positioning within the mediastinum.

Massive Systemic Air Embolism Following a Blunt Chest Injury

Massive Systemic Air Embolism Following a Blunt Chest Injury

A Comparison of Underwater Bubble Continuous Positive Airway Pressure with Ventilator-Derived Continuous Positive Airway Pressure in Premature Neonates Ready for Extubation

Objective and methods: As the result of vigorous bubbling, infants receiving continuous positive airway pressure (CPAP) by an underwater seal (bubble CPAP) were observed to have vibrations of their chests at frequencies similar to high-frequency ventilation (HFV). We performed a randomized crossover study in 10 premature infants ready for extubation to test whether bubble CPAP contributes to gas exchange compared to conventional ventilator-derived CPAP. Measurements of tidal volume and minute volume were made using the Bear Cub neonatal volume monitor, and gas exchange was measured using an oxygen saturation monitor and a transcutaneous carbon dioxide (tcpCO₂) monitor. Results: There was a 39% reduction in minute volume (p < 0.001) and a 7% reduction in respiratory rate (p = 0.004) with no change in tcpCO₂ or O₂ saturation for infants supported with bubble versus ventilator-derived CPAP. Conclusions: The lack of difference in blood gas parameters associated with a decrease in the infant’s minute volume and respiratory rate with bubble CPAP compared with ventilator-derived CPAP suggests that the chest vibrations produced with bubble CPAP may have contributed to gas exchange. Bubble CPAP may offer an effective and inexpensive option for providing respiratory support to premature infants.

Underwater seal chest drains: the patient's experience

Chest drains are routinely inserted during thoracic surgery and to conservatively manage spontaneous pneumothorax. An extensive search of the literature revealed only a small number of highly prescriptive articles to advise the nurse on the specific care needs of this patient group. An exploratory study undertaken with 18 patients drew attention to the persistent discomfort and pain experienced by patients throughout the entire time that the chest drain remained in situ. Most of the patients also experienced short-lasting but intense pain when the chest drain was removed. Patients appeared ill-prepared for their experiences despite opportunities to obtain verbal and written information from staff.

Underwater seal chest drains: the patient's experience

Underwater seal chest drains: the patient's experience

Repertoire and Geographic Variation in Underwater Vocalisations of Weddell Seals (Leptonychotes weddellii, Pinnipedia : Phocidae) at the Vestfold Hills, Antarctica

The underwater vocalisations of Weddell seals (Leptonychotes weddellii) near Davis, Antarctica, were many and varied. A total of 11029 vocalisations recorded throughout and immediately after the breeding season were analysed. Vocalisations were classified by cluster analysis techniques, based on differences in frequency, duration, call shape, waveform and number of elements. Thirteen broad call categories (many with subdivisions) were identified. Twelve call types (belonging to nine categories) made up 91· 9% of the vocalisations and were present at all seven study sites within the Vestfold Hills, and a single site at the Larsemann Hills approximately 150 km away. A further eight call types (five categories) made up another 6·7% of the vocalisations. These were not detected at every recording site. An additional 29 call types (11 categories) were infrequent and probably reflect the diversity of individual seals. This study strengthens the case for macrogeographic variation in underwater Weddell seal vocalisations around Antarctica. Microgeographic differences, between sites within 150 km, were weak and not consistent between sites or years. Some adult females move to different breeding sites within the Vestfold Hills area between years. This would probably preclude the establishment of site-specific (microgeographic) repertoire differences.

Evaluation of Conventional Chest Tube Therapy for Iatrogenic Pneumothorax

To assess conventional, large chest tube therapy in iatrogenic pneumothorax and to determine the optimal moment when to use more invasive procedures. Retrospective chart review. Medical intensive care unit of a university hospital. Forty-seven patients with needle-induced iatrogenic pneumothorax. Twenty-four patients had an underlying pleural or pulmonary disorder. After insertion of a 20- to 24-French plastic chest tube connected to an underwater seal, suction was maintained until gas egress stopped or up to 10 days in patients with a persisting gas leak. In 96 percent, a definite occlusion of the pneumothorax was achieved. In all patients without an underlying lung disorder, gas egress stopped definitely after 72 h. In the presence of an underlying lung disorder, 92 percent of the pneumothoraces were healed after 10 days of continuous suction therapy. At 72 h, only 71 percent of the latter group were healed (p < 0.05 vs patients without lung disease). No major complication of chest tube therapy occurred. Conventional chest tube therapy is a safe and effective treatment for iatrogenic pneumothorax. In patients with an underlying lung disease, gas egress may last for up to 10 days. In these patients, the earlier use of a more invasive approach may be justified if the air leak persists.