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A 2-day-old Holstein calf was admitted to the Veterinary Teaching Hospital (VTH) in St-Hyacinthe for respiratory distress. Thoracic auscultations revealed asymmetric lung sounds. A diaphragmatic hernia was diagnosed on thoracic radiographs. Herniorrhaphy was performed; postoperative recovery was uneventful. This case indicates that diaphragmatic hernia in calves can be surgically treated successfully.
Correction chirurgicale d’une hernie diaphragmatique chez un veau nouveau-né. Une génisse Holstein de deux jours a été présentée au Centre Hospitalier Universitaire Vétérinaire (CHUV) à St-Hyacinthe pour détresse respiratoire. L’auscultation thoracique a révélé des bruits pulmonaires asymétriques. Des radiographies thoraciques ont confirmé la présence d’une hernie diaphragmatique. Une herniorraphie a été effectuée. Le pronostic a été jugé bon. Le présent cas montre qu’il est possible de corriger chirurgicalement avec succès les cas d’hernie diaphragmatique chez le veau.
(Traduit par les auteurs)
A 2-day-old Holstein heifer was admitted to the Centre Hospitalier Universitaire Vétérinaire (CHUV) in Saint-Hyacinthe for respiratory distress. According to the owner, parturition was difficult and assistance was necessary. The dam was primiparous and the newborn weighed 50 kg (110 lb). The clinical findings from the referring veterinarian were: absence of suckling reflex, abnormal lung sounds, heart murmur audible on the left side, and diarrhea.
Upon arrival at the CHUV, the heifer was in lateral recumbency. She was experiencing severe respiratory distress: abdominal respiratory efforts were evident. The left flank was severely distended. Physical examination revealed a rectal temperature of 39.7°C, a heart rate of 180 beats/min, and a respiratory rate of 32 breaths/min. Dehydration was estimated at 5% to 7%, based on skin tent and sunken eyes. The capillary refill time was normal (< 2 s). Lung sounds were increased on the left side and absent on the right side. A left side ping was detected on the left flank localized over an area centered at the 8th intercostal space.
Differential diagnosis at this time included: unilateral pneu-mothorax, severe pneumonia, pleural effusion, diaphragmatic hernia, and rib fractures. Possible explanations for the left side ping were tympanism of the rumen or a left displaced abomasum. The following ancillary tests were recommended: a venous blood gas, a complete blood (cell) count (CBC), a serum biochemistry profile, and thoracic radiographs (lateral and ventro-dorsal). The venous blood gas indicated a low pH: 7.2 (normal range: 7.35 to 7.50), an elevated PCO2: 77.3 mmHg (normal range: 35 to 44 mmHg), and an elevated bicarbonate concentration: 30.3 mmol/L (normal range: 20 to 28 mmol/L), which was compatible with respiratory acidosis.
The CBC showed an elevated neutrophil count: 9.2 × 109/L (normal range: 0.6 to 4.0 × 109/L), presence of toxic neutro-phils, low lymphocyte count: 1.43 × 109/L (normal range: 2.5 to 7.5 × 109/L), increased fibrinogen concentration: 6 g/L (normal range: < 5 g/L), low total solids concentration: 54 g/L (normal range: 60 to 80 g/L). These results suggested a severe inflammatory response, as well as failure of passive transfer. The serum biochemistry profile showed elevated levels of blood urea nitrogen (BUN, 7.71 mmol/L; normal range: 1.61 to 6.51 mmol/L), creatinine (134 μmol/L; normal range: 54 to 132 μmol/L), aspartate transaminase (AST, 136 U/L; normal range: 30 to 104 U/L), and creatine kinase (CK: 959 U/L; normal range: 0 to 310 U/L). There was also a decreased blood level of gamma glutamyl transpeptidase (GGT, 63 U/L; normal range: 9.6 to 39 U/L) and Cl: 94.6 mmol/L (96.4 to 109.2 mmol/L). These parameters indicated that the heifer was dehydrated, had muscular damage, a failure of passive transfer, and digestive stasis.
Ventro-dorsal thoracic radiographic views (Figure 1) showed a gastric compartment into the right thoracic cavity, confirming the diagnosis of diaphragmatic hernia. Also, only the caudal portion of the left lung was properly filled with air.
Considering the genetic value of the animal, the owner agreed to pursue treatment. The only other option besides surgery in this case would have been euthanasia. The calf was first stabilized and its general condition was monitored until surgery. Four aspects needed to be addressed: dehydration, failure of passive transfer, respiratory distress, and possible infection. Intravenous fluid (Plasma-lyte 148; Baxter Corporation, Mississauga, Ontario), 3 L, was given over 24 h. Frozen plasma (2 L) was administered and oxygen (5 L/min) was insufflated intranasally. Intravenous sodium ampicillin (Ampicilline Sodium for Injection USP; Novopharm: Toronto, Ontario), 500 mg/vial, was also administered IV at 10 mg/kg. Continuous monitoring included: visual observations of the respiration, mucous membrane color, and regular arterial blood gas analysis. Heart rate and temperature were also monitored closely. The calf was kept in sternal position or in right lateral recumbency at all times, to optimize the left lung capacity.
The herniorrhaphy was performed under general anesthesia the next day. The heifer was premedicated with 5 mg diazepam IV (Diazepam INJ USP; 5 mg/mL; Sandoz Canada, Boucherville, Quebec) and 2.5 mg of butorphanol IV (Torbugesic Tartrate Injection USP; 10 mg/mL; Wyeth, St-Laurent, Quebec). Ketamine IV (Vetalar; Chlorhydrate de Ketamine Injection USB; 100 mg/mL; Bioniche Animal Health Canada, Belleville, Ontario), 150 mg, was used for induction, and anesthesia was maintained with isoflurane and oxygen. During the surgery, IV fluids were administered at a rate of 125 mL/h (Plasma-lyte 148 and 5% dextrose injection; Baxter Corporation). Frozen plasma (1 L) (part of the total of 2 L given) was also continued. Finally, a 0.1 mg/mL drip of Dobutamine was administered at a rate of 1 drop/3 s [0.12 mg/kg, body weight (BW)], for 45 min at the beginning of surgery (Dobutamine Injection USP; 12.5 mg/mL; Sandoz Canada). A second dose of 25 mg of ketamine IV was also given. Ketoprofen IV (Anafen; 100 mg/mL; Mérial Canada, Baie d’Urfé, Quebec), 150 mg, and ampicillin (ampicilline sodium for injection USP, 500 mg/vial, Novopharm), 500 mg IV, was administered preoperatively; ampicillin was repeated once during surgery. The calf was also on assisted ventilation (positive pressure: 17 respirations/min, 350 mL, 18 cm H2O) throughout the surgery. An additional 5 mg IM of butorphanol was administered at extubation.
The heifer was positioned in dorsal recumbency and surgically prepared. A 30-cm ventral midline incision from the umbilicus to the xyphoïd process was made. Once the abdominal cavity was opened, the hernia was confirmed: a 15-cm long tear was observed on the right muscular portion of the diaphragm. The bleeding edges of the tear suggested it was of traumatic origin. A careful reduction of the hernia was then performed and the liver, fore stomachs, small intestine, and spiral colon were returned to the abdominal cavity (Figure 2). Adhesions and fibrin were not observed on the herniated viscera or in the abdomen. The organs were not congested. The diaphragm was sutured dorsal to ventral with a simple continuous suture, PDS II 2-0 (Ethicon, Johnson and Johnson Medical Products, Markham, Ontario). A second layer was added with an interrupted horizontal mattress suture, Dexon 2-0 (Groupe Tyco Medical Canada, Saint-Laurent, Quebec). There was minimal tension on the suture line while closing the defect. The diaphragm was then attached directly to the manubrium sterni using Dexon 2-0 with simple interrupted sutures to decrease the tension on the more ventral diaphragmatic sutures. Once the thorax was completely closed, the thoracic negative pressure was re-established using a butterfly needle and a 60 mL syringe (Terumo). Approximately 120 mL of air was removed from the right thorax, and approximately 60 mL from the left side. The umbilical remnants looked normal. However, it was elected to remove the remnants to prevent postoperative potential umbilical infections. Abdominal muscles layers were sutured with PDS II USP 1 (Ethicon; Johnson and Johnson Medical Products) in interrupted cruciate fashion. The subcutaneous tissues were approximated with Dexon USP 2-0 (Groupe Tyco Medical Canada) with a continuous suture and the skin was closed with Supramid USP 1 (Serag Wiessner: Zum Kugelfang 12, 95119 Naila, Germany), in interrupted cruciate fashion. The duration of the surgery was 2.5 h. An adhesive surgical drape was applied on the surgical wound for 24 h (OPSITE: Smith and Nephew: 30 cm × 28 cm). Ketoprofen, 3 mg/kg BW, IV, was administered once post-operatively and sodium ampicillin, 10 mg/kg, BW, q8h, IV, for 5 d. No thoracic drain was left since the diaphragm was not under tension and negative thoracic pressure was successfully re-established during surgery.
The day after surgery, the heifer was standing, bright, alert, and responsive. Normal lung sounds were present on both sides. The heifer was bottle-fed and drank with appetite. Two days after surgery, the heifer was drinking milk, 6 L/d divided into 3 feedings. A control CBC was performed 24 h post-surgery and was within normal limits. Based on surgical findings and postoperative clinical evolution, the prognosis was good. The heifer was discharged from the hospital 10 d after surgery. The heifer is now more than 6 mo old and her growth rate is normal compared with other heifers of the same age.
Most diaphragmatic hernias reported in calves were postmortem findings (1–3). This is the first description of a successful diaphragmatic herniorrhaphy in a calf; there is one report of a failed attempt at a surgical correction of a hernia in a calf (4).
Neonatal diaphragmatic hernia may be congenital or acquired. Traumatic hernias are caused by mechanical factors such as pregnancy, falls, or dystocia. The increased abdominal pressure during parturition may induce a rupture in the diaphragm of the calf and the development of a hernia (1,5). Presence of fibrosis and thickening of the edges of the cleft are confirmation that the diaphragm has ruptured either as a result of trauma or spontaneously (6). In the present case, the hernia was most likely traumatic based on the surgical findings; the bleeding edges of the diaphragmatic tear, no surface of the diaphragm was missing (the edges of the tear could easily be apposed without tension) and the tear was in the muscular portion of the diaphragm.
Rapid recognition of the condition is essential if surgical treatment is to be attempted. Diaphragmatic hernia should be suspected in a newborn calf with dyspnea, absence or asymmetry of lung sounds, borborygma upon thoracic auscultation, tympanism, and colic. A wide range of signs are possible depending on the size and the location of the hernia and the amount and type of viscera displaced (5,7).
Thoracic radiographs are helpful to confirm a diagnosis of diaphragmatic hernia in small and large animals (5,8–11). The radiographs will reveal gastrointestinal content in the involved hemithorax with displacement of the mediastinal structures to the contralateral side. Additional imaging techniques may be necessary such as contrast radiography (5,10–12) and/or ultrasound (5,8,10). In cattle, the evidence of reticular motility at the level of the 4th and 5th intercostal spaces (right lateral wall of the thorax), indicates reticular herniation into the thorax (10). Abdominal exploration should also be considered to diagnose diaphragmatic hernia (11).
It seems extraordinary that the calf survived considering that most of the GI tract was in the thorax and that no respiratory support was provided on the farm and during transportation. The absence of strangulated viscera was probably a favorable element.
Diaphragmatic hernias pose 2 major anesthetic problems: 1) hypoventilation caused by the compression of the lung by the abdominal viscera, and 2) hypoxia due to the atelectatic lung (7). Stabilization of the cardiopulmonary function before the anesthesia is suitable (8,13). Positive pressure assisted ventilation is essential (7); however, high pressure should be avoided, due to the risk of re-expansion pulmonary edema (8). Maintenance of anesthesia with isoflurane or sevoflurane is recommended (8,13). Additive analgesic techniques should be used to promote a more stable depth of anesthesia and to decrease the quantity of inhalants necessary to maintain anesthesia (8).
A prosthetic patch might be used in large congenital or traumatic defects (7,9,14). When it is required, coverage of the mesh by peritoneum ensures that bowel does not attach to the mesh. This situation could cause an erosion of the bowel and subsequent perforation (15). In the present case, hernia closure was possible without excessive tension so no mesh was needed.
In conclusion, several factors contributed to the success of the present case: the development of imaging technologies, the ability to successfully anesthetize compromised patients using precise controlled ventilation, continuous direct blood pressure monitoring, frequent arterial blood gas evaluation and advanced surgical techniques.
The authors thank Dr. Nancie Richard for referring the case. CVJ
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