Suspected systemic gas embolism associated with lung tissue perforation caused by a previously inserted chest drain in a dog

OBJECTIVE

To report a case of systemic gas embolism associated with removal of a chest drain perforating a lung lobe in a dog undergoing sternotomy under general anesthesia and intermittent positive pressure ventilation.

CASE SUMMARY

An 8-year-old Cocker Spaniel underwent an exploratory thoracotomy via median sternotomy for surgical management of pyothorax that was treated conservatively for 7 days prior to referral following bilateral chest drain placement. The surgical procedure consisted of a subphrenic mediastinectomy and pericardiectomy. During surgery, it became apparent that the right drain was perforating the right middle lung lobe. Sudden desaturation and rapid hemodynamic deterioration occurred after the drain was removed. A systemic gas embolism was suspected on the basis of clinical signs and results of an arterial blood gas analysis, and immediate supportive treatment was started with an adequate response. Once the surgical procedure was completed, a clear "mill wheel" sound was audible on cardiac auscultation and point-of-care cardiac ultrasound confirmed the presence of gas bubbles in the cardiac chambers. The dog recovered from anesthesia and was managed in the intensive care unit where arterial blood gas analyses were nearly normal and the dog made a full recovery.

NEW OR UNIQUE INFORMATION PROVIDED

In people, there are reports of fatal air embolism related to the use of chest drains. To our knowledge, this is the first case report in dogs of a systemic gas embolism during open-chest surgery caused by a chest drain perforating a lung lobe. Immediate recognition and aggressive treatment of this life-threatening condition should be provided in order to achieve a favorable outcome.

Complications and outcome of traumatic diaphragmatic hernia repair without post-operative chest drain: Retrospective study in 90 cats

Background

Diaphragmatic herniorraphy is the treatment of choice for traumatic diaphragmatic hernia (TDH). Several methods have been described for the removal of residual air and fluid during and after surgery, such as the insertion of chest drains, intercostal thoracentesis, and transdiaphragmatic thoracentesis. However, there are no indications regarding the most useful technique and the impact that choice of technique could have in the immediate postoperative period.

Aim

To evaluate the development of complications and outcomes associated with the use of intraoperative transdiaphragmatic thoracentesis in cats undergoing diaphragmatic herniorrhaphy for TDH.

Methods

Medical records of cats treated for acute and chronic TDH between 2010 and 2019 were reviewed. Cats were included if intraoperative pneumothorax was treated with transdiaphragmatic thoracentesis, without the use of intercostal chest drain. Outcome, intra- and post-operative complications were recorded.

Results

Intraoperative and postoperative complication rates were 3.3% and 12.4%, respectively. Development of postoperative pneumothorax was associated with the presence of comorbidities (p = 0.046). The overall survival rate was 93.3%. Long-term survival had a significant association with the presence of comorbidities (p = 0.045), if the procedure was performed as an emergency (p = 0.041) or in older cats (p = 0.011).

Conclusion

Intraoperative transdiaphragmatic thoracentesis could be considered an effective method for the removal of residual air after surgery for TDH, because it ensures a good outcome for the patient, with low development of complications, especially for uncomplicated cases. The presence of comorbidities, the need to perform a surgical procedure in emergency, and the age of the patient can be considered factors influencing the development of complications. Critical patient selection, based on assessment of potential risk factors for complications is warranted to understand which patient will benefit from thoracostomy tube placement.

In vitro evaluation of negative pressure generated during application of negative suction volumes by use of various syringes with and without thoracostomy tubes

OBJECTIVE

To determine the amount of negative pressure generated by syringes of various sizes with and without an attached thoracostomy tube and whether composition of thoracostomy tubes altered the negative pressure generated.

SAMPLE

Syringes ranging from 1 to 60 mL and 4 thoracostomy tubes of various compositions (1 red rubber catheter, 1 polyvinyl tube, and 2 silicone tubes).

PROCEDURES

A syringe or syringe with attached thoracostomy tube was connected to a pneumatic transducer. Each syringe was used to aspirate a volume of air 10 times. Negative pressure generated was measured and compared among the various syringe sizes and various thoracostomy tubes.

RESULTS

The negative pressure generated decreased as size of the syringe increased for a fixed volume across syringes. Addition of a thoracostomy tube further decreased the amount of negative pressure. The red rubber catheter resulted in the least amount of negative pressure, followed by the polyvinyl tube and then the silicone tubes. There was no significant difference in negative pressure between the 2 silicone tubes. The smallest amount of negative pressure generated was -74 to -83 mm Hg.

CONCLUSIONS AND CLINICAL RELEVANCE

Limited data are available on the negative pressure generated during intermittent evacuation of the thoracic cavity. For the present study, use of a syringe of ≥ 20 mL and application of 1 mL of negative suction volume resulted in in vitro pressures much more negative than the currently recommended pressure of -14.71 mm Hg for continuous suction. Additional in vitro or cadaveric studies are needed.

Fluoroscopically guided wide-bore thoracostomy tube placement: Description of the technique and comparison to blind placement

OBJECTIVE

To describe and compare fluoroscopic guidance for placement of wide-bore thoracostomy tubes (FGTT) to traditional, blind placement of thoracostomy tubes (BPTT).

STUDY DESIGN

Prospective clinical trial.

ANIMALS

Twenty client-owned dogs.

METHODS

Dogs requiring medical management of pleural effusion received a BPTT, whereas dogs undergoing postoperative management of pneumothorax and/or pleural fluid after lateral thoracotomy received an FGTT. Time of placement, accuracy of positioning, radiation exposure, and complications were compared between groups.

RESULTS

Initial placement of BPTT took a mean of 168 seconds (range, 89-197), whereas adequate placement was radiographically confirmed at 20 minutes and 38 seconds (range, 7 minutes and 57 seconds to 39 min). Initial placement of FGTT took a mean time of 108 seconds (range, 50-341, P = .17), and adequate placement was confirmed at 125 seconds (range, 50-341, P < .001). Major errors in placement requiring removal and replacement occurred in 2 dogs for BPTT and in none for FGTT. Procedural complications did not differ between groups, and no postoperative complication occurred within the first 12 hours after placement. Radiation entrance surface dose was lower in the BPTT group (P = .004), but stochastic radiation doses did not differ.

CONCLUSION

Fluoroscopic guidance of wide-bore thoracostomy tubes accelerated the time to accurate tube placement and alleviated the requirement for removal and replacement in this population. Although use of fluoroscopy increased radiation entrance surface dose, the dose was not clinically significant.

CLINICAL SIGNIFICANCE

Fluoroscopic guidance of wide-bore thoracostomy tubes should be considered as an alternative to traditional, blind placement.

Use of vascular access ports with intrathoracic drains for treatment of pleural effusion in three dogs

CASE DESCRIPTION

3 dogs (9 to 12 years old) were evaluated because of recurrent pleural effusion that was refractory to treatment of the underlying cause.

CLINICAL FINDINGS

Dogs were evaluated because of cough, dyspnea, tachypnea, or lethargy or a combination of these clinical signs. Radiography, ultrasonography, or thoracocentesis were used to confirm the presence of pleural fluid in each dog. A neoplastic cause of pleural effusion was confirmed in 2 dogs. In 1 dog, fasciitis of the mediastinum and the left parietal pleura was diagnosed, with no evidence of neoplasia.

TREATMENT AND OUTCOME

Each dog was anesthestized, and thoracotomy was performed with manual perforation of the mediastinum. Permanent, subcutaneously placed vascular access ports were attached to intrathoracic, Jackson-Pratt drain tubing for repeated drainage of pleural fluid. Drains were used successfully in the 3 dogs for periods of 6 weeks, 11 weeks, and > 3 years.

CLINICAL RELEVANCE

Findings suggest that subcutaneous vascular access ports attached to intrathoracic drain tubing may be an effective way to remove recurrent pleural effusion in dogs.

The efficacy of mechanical abrasion and talc slurry as methods of pleurodesis in normal dogs

OBJECTIVE

To determine the efficacy of mechanical abrasion and talc slurry as methods for pleurodesis in normal dogs.

STUDY DESIGN

Experimental study.

ANIMALS OR SAMPLE POPULATION

Ten normal beagle dogs.

METHODS

Group I dogs had mechanical abrasion (MA) of the pulmonary and costal pleurae performed in one hemithorax with a dry gauze sponge with a median sternotomy approach. Group II dogs had 100 mL of a 1 g talc slurry (TS) administered into one hemithorax through a tube thoracostomy. Administration of the TS was visualized by using video thoracoscopy. All dogs were evaluated at 2, 10, 20, and 30 days postoperatively by means of thoracic radiography and ultrasonographic thoracic wall measurement. The dogs were euthanatized 30 days postoperatively and a gross necropsy was performed. Hemithoraces were assigned a pleurodesis score (0-4) and an obliteration grade (0-6). Tissues were collected for histopathologic examination of pulmonary pleura, costal pleura, and pleural adhesions. Pulmonary and costal pleurae were graded for the degree of fibrosis (0-4).

RESULTS

Obliteration grade and costal pleural fibrosis score were significantly higher for the treated sides in the MA dogs compared with the TS dogs. MA Dogs: Mechanical abrasion dogs had pleurodesis, obliteration, and pleural fibrosis scores that were greater on the treated side than the untreated side, however, the differences were not statistically significant. Only two MA dogs had firm adhesion of the pulmonary pleura to the costal pleura in portions of the cranial and middle lung lobes in the treated hemithorax. Thoracic wall surface area covered with adhesions was 15% and 21% in each of these two dogs. The median pulmonary pleural fibrosis score of all MA dogs for the treated hemithorax was 3 compared to 0 on the untreated side. TS Dogs: There was no statistical difference for pleurodesis scores and obliteration grades between the treated and untreated sides. No dogs showed evidence of pulmonary to costal pleural adhesions. Histopathology showed talc crossover into the untreated side in all five dogs. Median pulmonary fibrosis score of the treated hemithorax was 1 compared with 0 on the untreated side.

CONCLUSIONS

Neither method of pleurodesis produced sufficient pleural adhesions to obliterate the pleural space. It is possible that the degree of pulmonary pleural fibrosis present in MA dogs may be sufficient to limit air leakage from pulmonary blebs and bullae resulting in successful treatment of spontaneous pneumothorax.

Pneumothorax secondary to Dirofilaria immitis infection in two cats

Dirofilariasis was diagnosed in 2 cats with spontaneous pneumothorax. One cat had a 3-week history of a cough, and the other had an 11-month history of vomiting and tachypnea. Pneumothorax was managed in cats by thoracocentesis and supportive care. Diagnosis of dirofilariasis was made on the basis of heartworm antigen and antibody test results and radiographic findings. Clinical signs of heartworm infection improved after treatment with corticosteroids. Cats had good extended outcomes. Heartworm disease should be one of the differential diagnoses considered in cats with spontaneous pneumothorax.