Page 361 - Clinical Small Animal Internal Medicine

33 Surgical Approaches to Thoracic Disease 329

therapy for protein replacement in critically ill patients is sodium ion concentration within the airways, increasing
VetBooks.ir to provide enteral nutrition in order for the patient to pulmonary stretch receptor activity.
synthesize albumin.

Oxygen Therapy Hypothermia
Hypothermia is an inevitable occurrence during and
Oxygen therapy may be provided intermittently via face- immediately following thoracic surgery. Warming IV
mask or continuously by nasopharyngeal insufflation, fluids prior to administration can help diminish
nasal prongs, oxygen cage, or intubation and mechanical large reductions in intraoperative body temperature.
ventilation. Provision of intermittent supplemental oxy- Postoperative temperature monitoring, either intermit-
gen at an FiO 2 of 50–60% can be achieved via facemask tent or continuous, is recommended to ensure euther-
with oxygen flow rates of 8.0–12.0 L/min. Nasopharyngeal mia and active warming using warming blankets or
insufflation or nasal prongs may be utilized with oxygen heat lamps should be performed until the patient’s tem-
flow rates of 50–150 mL/kg/min to achieve an FiO 2 of perature has reached 99.5 °F.
30–70%. More commonly, postoperative thoracotomy
patients are maintained in an oxygen cage with flow rates Arrhythmias
of 0.5–1.0 L/min to maintain a FiO 2 of 40–60%. Patients
requiring an FiO 2 above 60% to maintain normoxemia For hemodynamically significant, multifocal, sus-
will likely require intubation and mechanical ventilation. tained, or R‐on‐T phenomena ventricular arrhythmias,
Caution must be exercised to avoid oxygen toxicity when lidocaine remains the mainstay therapy. Lidocaine may
supplemental oxygen levels are maintained above 60% also be useful to slow the heart rate, allowing differen-
for more than 24 hours. tiation of ventricular tachycardia from sinus tachycar-
When mechanical ventilation is utilized, PEEP ven- dia with bundle branch block. The waveform of the
tilation can be beneficial to prevent atelectasis and latter often will not change following lidocaine bolus
augment work of breathing. In contrast to the sponta- (2.0 mg/kg IV), but P‐waves may be appreciable once
neously breathing patient, permissive hypercapnia is the heart rate has decelerated. For lidocaine‐respon-
tolerated in mechanically ventilated postthoracotomy sive arrhythmias, a constant rate infusion of 60–80 μg/
patients. Arterial PCO 2 may rise to 50 mmHg before kg/min may be implemented postoperatively. A beta‐
intervention is necessary, as long as normoxemia is blocker may also be considered for patients that do not
maintained. Proper humidification is an important have known underlying cardiac disease with compro-
component of oxygen therapy for preservation of mised contractility. Anecdotally, sotalol 2.0 mg/kg PO
proper mucociliary function and clearance of respira- BID has favorable postoperative antiarrhythmic
tory secretions. properties for patients with supraventricular and ven-
tricular tachyarrhythmias.
Dyspnea
Nursing Care
Dyspnea is the perceived feeling of breathlessness. The
pathophysiology of dyspnea is multifactorial and is Nursing care is a critical yet often underemphasized
described elsewhere. Multiple therapeutic targets have aspect of postthoracotomy care. Patients undergoing
been investigated to decrease the perception of dyspnea median sternotomy often prefer lateral recumbency in
in human patients. In human studies, nebulized or aero- the immediate postoperative period due to incisional
solized furosemide has been found to prevent bronchoc- pain. Turning or rotating the patient every 4–6 hours
onstriction and inhibit the cough reflex in addition to prevents atelectasis and V–Q mismatching secondary to
reducing pulmonary vascular hydrostatic pressure and gravitational forces in lateral recumbency. Turning the
edema when absorbed systemically. Furosemide has patient also promotes patient comfort and hygiene.
been shown experimentally and clinically in people to Optimal analgesia aids in patient well‐being and may
reduce bronchial slow‐acting receptors (SARs), thereby promote tolerance of sternal recumbency and therefore
reducing the sensation of dyspnea. Furosemide exerts a improved oxygenation and ventilation.
diuretic effect when administered by the enteral or par-
enteral route via inhibition of the Na:K:2Cl co‐trans- Complications
porter within the thick ascending loop of Henle. A
similar mechanism is postulated for the antidyspneic Complications post thoracotomy may include edema
effect of nebulized furosemide causing a local increase in formation, hypoproteinemia, continual pleural effusion,