Retrospective evaluation of the impact of hypoxemia during thoracic surgery in dogs on outcome: a multicenter analysis of 94 cases.

OBJECTIVE: To investigate the statistical association of severe intraoperative hypoxemia in thoracic surgery with mortality, postoperative hospitalization times and cost of care. STUDY DESIGN: Retrospective study. ANIMALS: Dogs that underwent thoracic surgery in three veterinary hospitals between October 1, 2018 and October 1, 2020. METHODS: Anesthesia and hospitalization records from 112 dogs were reviewed and 94 cases met inclusion criteria. Recorded data included signalment, disease etiology, pulmonary or extrapulmonary nature of disease, surgical procedure performed, episodes of severe intraoperative hypoxemia defined as a pulse oximetry reading (SpO2) <90% of 5 minutes or longer duration, survival to discharge, time from extubation to hospital discharge and total invoice cost for clinical visit. Dogs were divided into two groups, those that experienced severe hypoxemia (group A) and those in which SpO2 reading <90% was not observed throughout the procedure (group B). RESULTS: Group A had a greater risk of mortality (odds ratio 10.6, 95% confidence interval 1.9-106.7; p = 0.002), prolonged hospitalization (median 62 hours versus 46 hours; p = 0.035) and more expensive cost of care (median US$10,287 versus $8506; p = 0.056) than group B. No significant difference was found for the type of surgical procedure or pulmonary versus extrapulmonary nature of disease. CONCLUSIONS AND CLINICAL RELEVANCE: Severe intraoperative hypoxemia was statistically associated with an increased risk of mortality and longer postoperative hospitalization times. Although not achieving statistical significance, there was a trend toward increased costs to the client for animals with intraoperative hypoxemia.

Crimped monofilament nylon leader for median sternotomy closure in 10 dogs.

OBJECTIVE: To describe and report the outcomes after closure of median sternotomies with crimped monofilament nylon leader (MNL) in dogs. STUDY DESIGN: Retrospective observational study. ANIMALS: Dogs (n = 10) that underwent intrathoracic surgery through a median sternotomy approach. METHODS: The median sternotomy was closed in a peristernal figure eight pattern with crimped MNL. Medical records were reviewed for clinical and histopathological findings and complications. Owners or veterinarians were contacted to collect long-term follow-up information. RESULTS: The technique was simple, with no intraoperative complications. Postoperative infection was documented in one dog, requiring removal of a single MNL and associated crimp clamp. Delayed healing of the surgical incision in one dog was managed conservatively. No other complications were documented throughout long-term follow-up at a median of 488 days (range, 199-608). CONCLUSION: Median sternotomies were successfully closed with crimped MNL and were associated with a low complication rate. CLINICAL SIGNIFICANCE: Crimped MNL represents an alternative method to close median sternotomies in dogs.

Thoracic dog bite wounds in dogs: A retrospective study of 123 cases (2003-2016).

OBJECTIVE: To report the clinical, radiographic, and surgical findings and determine prognostic factors for outcome in dogs with thoracic dog bite wounds. STUDY DESIGN: Retrospective study. ANIMALS: Client-owned dogs (n = 123). METHODS: Medical records of dogs with thoracic dog bite wounds between October 2003 to July 2016 were reviewed for presenting findings, management, and outcomes. Standard wound management included debridement and sterile probing, extending the level of exploration to the depth of the wound. Univariable and multivariable binary logistic regression were used to assess risk factors for exploratory thoracotomy, lung lobectomy, and mortality. RESULTS: Twenty-five dogs underwent exploratory thoracotomy, including lung lobectomy in 12 of these dogs. Presence of pneumothorax (odds ratio [OR] 25.4, confidence interval (CI) 5.2-123.2, P < .001), pseudo-flail chest (OR 15.8, CI 3.2-77.3, P = .001), or rib fracture (OR 11.2, CI 2.5-51.2, P = .002) was associated with increased odds of undergoing exploratory thoracotomy. Presence of pleural effusion (OR 12.1, CI 1.2-120.2, P = .033) and obtaining a positive bacterial culture (OR 23.4, CI 1.6-337.9, P = .021) were associated with increased odds of mortality. The level of wound management correlated with the length of hospitalization (Spearman rank order correlation = 0.52, P < .001) but was not associated with mortality. CONCLUSION: Dogs that sustained pseudo-flail chest, rib fracture, or pneumothorax were more likely to undergo exploratory thoracotomy. Nonsurvival was more likely in dogs with pleural effusion or positive bacterial culture. CLINICAL SIGNIFICANCE: Presence of pseudo-flail, rib fracture, or pneumothorax should raise suspicion of intrathoracic injury. Strong consideration should be given to radiography, surgical exploration, and debridement of all thoracic dog bite wounds.

Prospective evaluation of surgical management of sliding hiatal hernia and gastroesophageal reflux in dogs.

OBJECTIVE: To evaluate response to surgical management of sliding hiatal hernia (SHH) and gastroesophageal reflux (GER) in dogs using standardized clinical scoring, videofluoroscopic swallow studies, and impedance planimetry. STUDY DESIGN: Prospective clinical trial. ANIMALS: A total of 17 client-owned dogs. METHODS: Dogs were included if they had clinical signs and videofluoroscopic evidence of SHH and/or GER. Owners were asked to complete a standardized canine dysphagia assessment tool (CDAT) preoperatively and postoperatively. Conscious videofluoroscopic swallowing studies and impedance planimetry (IP) were used to evaluate esophageal function and lower esophageal sphincter location and geometry preoperatively and in a subsection of dogs postoperatively. RESULTS: Preoperatively, 13/17 dogs included in the study had a history of regurgitation, and 4/17 had radiographic evidence of aspiration pneumonia. Postprandial regurgitation improved in 8/10 dogs with preoperative regurgitation, and for which completed preoperative and postoperative CDAT questionnaires were available (P < .01). The hiatal hernia severity score improved postoperatively (P = .046) in dogs with preoperative and postoperative videofluoroscopic swallowing studies (n = 12). However, hernia frequency score (P = .2) and IP parameters did not differ significantly between time points. CONCLUSION: Clinical signs of SHH generally improved with surgery but did not consistently resolve. Videofluoroscopic studies provide evidence that GER and SHH can persist postoperatively in some patients. Based on IP findings, clinical improvement may be attributed to a mechanism independent of lower esophageal sphincter attenuation.

The effect of experience, simulator-training and biometric feedback on manual ventilation technique.

OBJECTIVE: To determine the frequency of provision and main providers (veterinary surgeons, nurses or trainees) of manual ventilation in UK veterinary practices. Furthermore, to determine the variation in peak inspiratory (inflation) pressure (PIP), applied to a lung model during manual ventilation, by three different groups of operators (inexperienced, experienced and specialist), before and after training. STUDY DESIGN: Questionnaire survey, lung model simulator development and prospective testing. METHODS: Postal questionnaires were sent to 100 randomly selected veterinary practices. The lung model simulator was manually ventilated in a staged process over 3 weeks, with and without real-time biometric feedback (PIP display), by three groups of volunteer operators: inexperienced, experienced and specialist. RESULTS: The questionnaires determined that veterinary nurses were responsible for providing the majority of manual ventilation in veterinary practices, mainly drawing on theoretical knowledge rather than any specific training. Thoracic surgery and apnoea were the main reasons for provision of manual ventilation. Specialists performed well when manually ventilating the lung model, regardless of feedback training. Both inexperienced and experienced operators showed significant improvement in technique when using the feedback training tool: variation in PIP decreased significantly until operators provided manual ventilation at PIPs within the defined optimum range. Preferences for different forms of feedback (graphical, numerical or scale display), revealed that the operators' choice was not always the method which gave least variation in PIP. CONCLUSIONS AND CLINICAL RELEVANCE: This study highlighted a need for training in manual ventilation at an early stage in veterinary and veterinary nursing careers and demonstrated how feedback is important in the process of experiential learning. A manometer device which can provide immediate feedback during training, or indeed in a real clinical setting, should improve patient safety.

Reparo de lesão penetrante em parede torácica de cão, ocasionada por javali (Sus scrofa scrofa), com flape unipediculado de músculo reto abdominal / Unipediculated flap of muscle rectos abdominales to repair a penetrating injury caused by javali (Sus scrofa scrofa) on the thoracic wall of a dog

Lesões penetrantes no tórax causadas por interação animal são frequentes em cães e caracterizam-se por dano extenso e desvitalização dos tecidos moles adjacentes. Quando a musculatura local é insuficiente para a reconstrução, retalhos musculares podem ser mobilizados para reparar o defeito torácico. O presente relato tem como objetivo demonstrar uma alternativa para o reparo de defeito da parede torácica em um cão, ocasionada por interação com javali (Sus scrofa scrofa), utilizando flape unipediculado de músculo reto abdominal. Com base na literatura consultada, essa técnica reconstrutiva ainda não foi descrita. O flape de músculo reto abdominal mostrou-se uma alternativa viável no reparo de lesão extensa e infectada na parede torácica em cães.(AU)

Penetrating thoracic wounds caused by animal bites are common in dogs and are characterized by extensive trauma and adjacent soft tissue devitalization. When the local musculature is insufficient for the reconstruction, muscle flaps can be taken to repair the thoracic defect. The aim of the present report is to demonstrate an alternative to the thoracic wall defect repair in a dog which was attacked by javali (Sus scrofa scrofa), using unipediculated flap of the rectus abdominis muscle. Based on the literature, this reconstructive technique has not yet been described. The rectus abdominis muscle flap proves to be a useful alternative for the repair of extensive and infected thoracic wall lesion in dogs.(AU)

Rabbit Soft Tissue Surgery.

This article summarizes the available information on different soft tissue surgical procedures in rabbits, based on the literature and the authors' experiences, emphasizing the differences between rabbits and the more familiar dogs and cats. The major surgical principles in rabbits are discussed, and common surgical procedures, such as abdominal exploration, gastrotomy, enterotomy, liver lobectomy, nephrectomy, cystotomy, cystectomy, ovariohysterectomy, ovariectomy, orchidectomy, are described.

Current concepts in minimally invasive surgery of the thorax.

Thoracoscopy is a technique that has been shown to decrease patient morbidity and is rapidly becoming more diversely applied for diagnostic and therapeutic interventions in veterinary medicine. This article describes the basic equipment and application of thoracoscopy in small animal surgery. The diagnostic and therapeutic applications are introduced and briefly described.

Preventive incisional negative pressure wound therapy (Prevena) for an at-risk-surgical closure in a female Rottweiler.

This case report describes a combination of negative pressure-wound-therapy (NPWT) and NPWT assisted incision management after resection of an abscess located at the right thoracic wall in a Rottweiler. The patient had a history of severe incisional complications after surgical interventions performed in the past, including repeated episodes of wound dehiscence, major skin necrosis and infection with and without a multiresistant strain of Staphylococcus aureus and several episodes of open wound management with healing rates between months and a year. Wound closure after resection of the mass was performed as a staged procedure. After two days of open NPWT the wound was primarily closed and a preventive incisional vacuum assisted therapy (CI-NPWT) was started for 7 days. The patient was discharged during therapy with the portable device in place. The Unit was removed at day 7 post wound closure, suture removal followed at day 10. Wound healing was uneventful and no major complications occurred at a follow up time of 8 months. This is the first description of closed incisional negative pressure wound therapy in the dog.

Surgical repair of a congenital sternal cleft in a cat.

OBJECTIVE: To describe the clinical findings, diagnosis, and treatment of an incomplete cleft of the 5th-8th sternebra and a cranioventral abdominal wall hernia in a 2 month old Ragdoll kitten and to evaluate the short- and long-term outcome. STUDY DESIGN: Clinical report. ANIMALS: Ragdoll cat (n = 1), 2 months old. METHODS: Sternal cleft was confirmed by thoracic radiographs. Computed tomography (CT) was used to plan an optimal surgical approach. A ventral median incision was made, starting at the 3rd sternebra and extended into the abdomen. Ostectomy of the proximal part of the 5th left sternebra was performed. Lateral periosteal flaps were created, unfolded, and absorbable monofilament sutures preplaced to facilitate closure and the repair was reinforced by 2 peristernal sutures. A bone graft was applied, and the free margin of the omentum was sutured to the cranial aspect of the wound. RESULTS: No major complications occurred. At 3 weeks, CT scan confirmed approximation of the hemisternebrae and at 10 months, complete fusion of the hemisternebrae had not occurred, but a strong connection of the sternal bars was present. CONCLUSION: Sternal cleft is a rare congenital abnormality that can be corrected surgically with favorable outcome.

Predictors of outcome in dogs undergoing thoracic surgery (2002-2011).

OBJECTIVE: To evaluate mortality in a canine population undergoing thoracic surgery and identify factors which may be associated with outcome. STUDY DESIGN: Retrospective cohort study. ANIMALS: 286 dogs anaesthetized for thoracic surgery at the Royal Veterinary College between June 2002 - June 2011. METHODS: Variables examined included: signalment; ASA status; nature of disease; presence of co-morbidities; pre-anaesthetic oxygen requirement; surgical approach; anaesthesia management [anaesthetic agents; requirement for thoracocentesis; central venous pressure measurement; duration of surgery and anaesthesia; use of colloids, blood products, inotropes or neuromuscular blocking agents (NMBA)]. Outcome was defined as either non-survival to 24 hours after surgery or (having survived to 24 hours) to discharge. Univariate and multivariable logistic regressions were performed to identify risk factors associated with non-survival. RESULTS: Overall non-survival (excluding those euthanased) to discharge was 5.9%. Non-survival was 2.2% at 24 hours and 3.6% at time of discharge. Non-survival to 24 hours was associated with pre-anaesthetic oxygen requirement (odds ratio (OR) 12.2 [95% CI 1.8-84.5]) and NMBA use (OR 9.6 [95% CI 1.6-57.9]). Non-survival to discharge was associated with surgical duration, with surgeries >180 minutes having OR 16.9 [95% CI 2.0-144.0] compared to surgeries ≤90 minutes and blood product use (OR 4.6 [95% CI 1.3-14.6]). No association was found between ASA category and non-survival at 24 hours (OR 1.4 [95% CI 0.2-11.7]) or discharge (OR 4.4 [95% CI 0.6-34.3]). Significant associations were found between NMBA use and ASA category (p = 0.046), surgical duration (p = 0.002), use of colloids (p = 0.011), blood products (p = 0.001) and inotropes and/or vasopressors (p < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE: Variables significantly associated with non-survival from canine thoracic surgery at 24 hours include NMBA use and pre-anaesthetic oxygen requirement. Blood product use and increasing surgical duration were associated with non-survival to hospital discharge. The associations may relate to the need for such products in the most complicated cases.

Prevalence, outcome and risk factors for postoperative pyothorax in 232 dogs undergoing thoracic surgery.

OBJECTIVE: To determine the prevalence, outcome and risk factors for postoperative pyothorax in dogs undergoing thoracic surgery. METHODS: Case records were reviewed retrospectively to identify dogs with post thoracic surgery pyothorax, defined as septic neutrophilic inflammation within the pleural space based on cytology and/or a positive bacterial culture of pleural fluid. Those identified were reviewed for potential risk factors for postoperative pyothorax based on biological plausibility and previously published data. These potential risk factors were explored by multivariable logistic regression. RESULTS: Of 232 dogs undergoing thoracic surgery, 15 (6.5%) dogs developed pyothorax. Bacteria cultured included methicillin-resistant Staphylococcus aureus and multi-resistant Escherichia coli. Of these dogs, six died, four were euthanased and five were treated successfully. A diagnosis of idiopathic chylothorax [Odds Ratio (OR)=12.5, 95% Confidence Interval (CI)=2.7-58.5, P=0.001], preoperative intrathoracic biopsy (OR=14.3, 95% CI=1.7-118.7, P=0.014) and preoperative thoracocentesis (OR=11.2, 95% CI=1.6-78.2, P=0.015) were identified as independent risk factors for development of postoperative pyothorax. CLINICAL SIGNIFICANCE: Idiopathic chylothorax, intrathoracic biopsy and prior thoracocentesis are independent risk factors for postoperative pyothorax, which was associated with a 67% mortality rate.

Clean technique for prolonged nonsurvival cardiothoracic surgery in swine (Sus scrofa).

Laboratory animal regulations provide little guidance regarding duration of nonsurvival surgery requiring aseptic technique. We hypothesized that swine would experience no sepsis during nonsurvival cardiothoracic surgery accomplished by using clean technique and lasting 8 h or less. Incision sites of 5 male farm pigs (Sus scrofa) were shaved and then cleaned with alcohol and povidone-iodine. The surgeon wore sterile gloves, clean scrubs, and hair bonnet; assistants wore clean scrubs and nonsterile gloves; most instruments were autoclaved. A median sternotomy incision was used for thoracic cavity exposure, and the skull was exposed to allow induction of brain death. Heart rate, body temperature, and blood samples were obtained before surgery (0 h; baseline) and at 2, 4, 5 or 6, and 7 or 8 h thereafter. Statistical analysis by t-tests showed that heart rate was unchanged and body temperature increased after the 0-h (baseline) time point. Aerobic blood cultures were negative except for 2 samples that were positive for coagulase-negative Staphylococcus spp. at 4 h. RBC, Hgb, and Hct levels were decreased at 2 and 4 h, but WBC and platelets were unchanged. Other alterations included decreased glucose (at 7 or 8 h), increased BUN (at 5 or 6 h and 7 or 8 h) and creatinine (at 5 or 6 h), decreased Na(+) and Ca and increased K(+) (most time points), decreased total protein and albumin (most time points), and decreased globulin (at 7 or 8 h). Liver enzymes and bilirubin typically were unchanged, and cholesterol consistently was decreased. Together our results indicate a lack of sepsis for 8 h or less in pigs undergoing cardiothoracic surgery by using clean technique. These findings provide new and specific data regarding the use of aseptic technique during prolonged nonsurvival surgeries.

Surgical optimization and characterization of a minimally invasive aortic banding procedure to induce cardiac hypertrophy in mice.

Left ventricular pressure overload in response to aortic banding is an invaluable model for studying progression of cardiac hypertrophy and transition to heart failure. Traditional aortic banding has recently been superceded by minimally invasive transverse aortic banding (MTAB), which does not require ventilation so is less technically challenging. Although the MTAB approach is superior, few laboratories have documented success, and minimal information on the model is available. The aim of this study was to optimize conditions for MTAB and to characterize the development and progression of cardiac hypertrophy. Isofluorane proved the most suitable anaesthetic for MTAB surgery in mice, and 1 week after surgery the MTAB animals showed significant increases in systolic blood pressure (MTAB 110 ± 6 mmHg versus sham 78 ± 3 mmHg, n = 7, P < 0.0001) and heart weight to body weight ratio (MTAB 6.2 ± 0.2 versus sham 5.1 ± 0.1, n = 12, P < 0.001), together with systolic (e.g. fractional shortening, MTAB 31.7 ± 1% versus sham 36.6 ± 1.4%, P = 0.01) and diastolic dysfunction (e.g. left ventricular end-diastolic pressure, MTAB 12.7 ± 1.0 mmHg versus sham 6.7 ± 0.8 mmHg, P < 0.001). Leucocyte infiltration to the heart was evident after 1 week in MTAB hearts, signifying an inflammatory response. More pronounced remodelling was observed 4 weeks postsurgery (heart weight to body weight ratio, MTAB 9.1 ± 0.6 versus sham 4.6 ± 0.04, n = 10, P < 0.0001) and fractional shortening was further decreased (MTAB 24.3 ± 2.5% versus sham 43.6 ± 1.7%, n = 10, P = 0.003), together with a significant increase in cardiac fibrosis and further cardiac inflammation. Our findings demonstrate that MTAB is a relevant experimental model for studying development and progression of cardiac hypertrophy, which will be highly valuable for future studies examining potential novel therapeutic interventions in this setting.

Long-term outcome of dogs treated surgically for idiopathic chylothorax: 11 cases (1995-2009).

OBJECTIVE: To determine long-term outcome of dogs treated surgically for idiopathic chylothorax. DESIGN: Retrospective case series. ANIMALS: 11 client-owned dogs with idiopathic chylothorax that underwent surgery between November 1995 and April 2009 and had been followed up for at least 4 months after surgery. PROCEDURES: Medical records were reviewed for information on signalment, history, physical examination findings, results of clinicopathologic testing, radiographic findings, surgical procedures, postoperative complications, outcome, and cause of death. RESULTS: A median sternotomy was performed in 10 dogs, and a right intercostal thoracotomy (fifth and ninth intercostal spaces) was performed in 1. Thoracic duct ligation and subtotal pericardectomy were performed in all dogs. Thoracic omentalization was performed in 8 dogs at the time of surgery, passive pleuroperitoneal shunting was performed in 2 dogs, and pleurodesis was performed in 1 dog. Lung lobectomy was performed because of lung consolidation in 2 dogs and lung lobe torsion in another 2 dogs at the time of the initial surgery. Median disease-free interval did not differ significantly between dogs that did and did not undergo lung lobectomy. Postoperative complications occurred in 5 dogs. Median follow-up time was 46 months. Eight of 11 dogs were free from clinical signs 5 years after surgery. Two of the 3 dogs that did not undergo thoracic omentalization had a recurrence of clinical signs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the prognosis for dogs surgically treated for idiopathic chylothorax was fair and that lung lobectomy was not a negative prognostic indicator.

Omentalisation of a caudal mediastinal abscess in a dog.

A caudal mediastinal abscess was diagnosed in a 2-year-old German Short-haired Pointer with acute onset of lethargy, pyrexia and tachypnoea. The abscess was managed surgically by median sternotomy, abscess content evacuation and omentalisation of the abscess cavity via the diaphragm. Although surgical management of mediastinal abscesses has been reported previously, this is the first report to describe successful management of the condition in a dog by omentalisation.

Single paracostal approach to thoracic duct and cisterna chyli: experimental study and case series.

OBJECTIVE: To-determine the feasibility of a single paracostal abdominal approach for thoracic duct ligation (TDL) and cisterna chyli ablation (CCA) in dogs with chylothorax. STUDY DESIGN: Observational study and prospective case series. ANIMALS: Normal dogs (n = 5) and dogs with chylothorax (n = 8). METHODS: A single paracostal approach with transdiaphragmatic extension for TDL and CCA was developed experimentally (n = 5) and used in 8 clinical cases with subtotal pericardectomy (SPE) performed in 4 dogs. Surgery time, complications, hospitalization time, outcome, and follow-up of clinical cases were recorded. RESULTS: Exposure of relevant anatomy was excellent; vital lymphatic staining facilitated identification of lymphatic structures. In clinical cases, mean surgery time for TDL + CCA was 136 minutes. Mean hospitalization time was 3.1 days. Seven of 8 cases survived, with 1 dog dying of heart failure shortly after discharge. One dog required a second (left) paracostal approach to ligate 2 more lymphatic vessels. On follow-up (median, 7 months; range, 2-20 months), there was complete resolution of chylothorax in 6 dogs. CONCLUSIONS: A single paracostal approach provides excellent exposure of cisterna chyli, caudal thoracic duct, and intestinal lymphatics. This approach eliminates the need for repositioning during combined TDL + CCA procedures and avoids an intercostal thoracotomy.

Diaphragmatic support of a thoracic wall defect in a dog.

A large, caudal thoracic mass was removed along with ribs 11 and 12, resulting in an approximate 16 x 14-cm, caudal thoracic wall defect in a dog. The diaphragmatic musculature was mobilized and used to support the thoracic wall defect. To our knowledge, this method of thoracic wall repair has not been previously reported. This procedure allowed for airtight closure of the thoracic cavity, provided physical support, eliminated the need for muscle flaps or commercially available meshes, and provided a good cosmetic appearance without negatively affecting the dog's athletic performance.