Figure 5.3 Intraoperative photograph showing the removal of a large nasogastric tube fragment (1.3 cm diameter, 90 cm long) through a full thickness enterotomy in the right dorsal colon. This horse presented with acute signs of colic, but had no known history of prior nasogastric intubation complications. It was presumed that the nasogastric tube fragment had been acquired prior to the current ownership of the horse and did not cause problems until it migrated to the transverse colon and caused obstruction.

      Source: Courtesy of Isabelle Kilcoyne.

       Prevention

      Prevention of inadvertent administration of fluids into the lungs is an essential part of nasogastric intubation procedures. Please refer to the section describing misplacement of nasogastric tubes for specific preventative procedures. Careful attention to all precautions throughout the nasogastric intubation procedure will help to minimize complications.

       Diagnosis

      Development of respiratory distress immediately following a nasogastric tube procedure is highly suggestive of inadvertent pulmonary administration of fluid. Signs may be delayed by a few days in cases with a small amount of mineral oil aspiration. Diagnosis of contamination of the lungs with mineral oil, also described as mineral oil‐induced pneumonitis or lipoid pneumonia, is based on a history of mineral oil administration, radiographic or ultrasonographic evidence of pneumonia, and the identification of oil in tracheal wash or bronchoalveolar lavage samples [13–17].

       Treatment

      If a small amount of clean water is inadvertently administered into the lungs, the horse should be placed on anti‐inflammatory treatment and antimicrobial therapy to prevent pneumonia [1]. Administration of larger volumes of fluid may require additional supportive care, such as furosemide to treat pulmonary edema, bronchodilators, and intranasal oxygen therapy. Inadvertent intratracheal administration of certain medications (e.g. deworming drenches) [12] and mineral oil [13, 15–19] may have fatal consequences, even with aggressive treatment. These horses should be aggressively treated with antimicrobial therapy, anti‐inflammatory medications, bronchodilators, nebulization, and intra‐nasal oxygen [13–17]. Repeated bronchoalveolar lavage and lung lobectomy has been reported to be helpful in people with mineral oil aspiration, but it has not been described in the equine case reports [16, 17]. There is one report of successful treatment of lipoid pneumonia, from aspiration of mineral oil, in which dexamethasone treatment was used [14]; however, other authors have reported use of corticosteroids as part of their treatment efforts in cases with unsuccessful outcomes [15].

       Expected outcome

      A small amount of clean water inadvertently administered into the lungs may be tolerated; however, the horse should be placed on prophylactic treatment to prevent pneumonia [1]. In contrast, a small amount of mineral oil aspirated into the lungs in nearly invariably fatal [13–17].

Sinusitis

       Definition

      Sinusitis is the accumulation of suppurative exudate within the paranasal sinuses of the horse and typically results in malodorous nasal discharge with or without pyrexia.

       Risk factors

       Pathogenesis

      Unilateral or bilateral sinusitis has been described as a rare complication of nasogastric intubation [18, 19]. Pathogenesis is assumed to be related to overwhelming of normal sinus defense mechanisms by impediment of normal sinus drainage (inflammation and swelling of mucosa secondary to indwelling tubes), increased bacterial load (prolonged intubation, use of a contaminated tube, or feed contamination of sinuses), or propagation of bacterial growth (blood contamination).

       Prevention

      Nasogastric tube‐associated sinusitis may be minimized by prophylactically lavaging the nasal passages if they are contaminated with gastrointestinal reflux during colic surgery and by using clean, disinfected nasogastric tubes for as short a time as possible [18].

       Diagnosis

      Clinical signs are the development of suppurative nasal discharge and fever [18]. Radiographs of the paranasal sinuses and endoscopy of the upper respiratory tract can localize the disease to the paranasal sinuses.

       Treatment

      Treat with systemic antimicrobial therapy and lavage of the affected sinuses via trephination. Sinusotomy via sinonasal flap may be necessary in selected cases.

       Expected outcome

      Prognosis with appropriate treatment should be good.

References