Asian Cardiovasc Thorac Ann 2005;13:377-379
© 2005 Asia Publishing EXchange Ltd
Coronary Artery Bypass Surgery in A Patient with a Functional Single Lung
Levent Yazicioglu, MD,
Atilla Aral, MD,
Ozge Uymaz, MD,
Hakki Akalin, MD
Department of Cardiovascular Surgery, Ankara University Hospital, Ankara, Turkey
For reprint information contact: Levent Yazicioglu, MD Tel: 90 312 266 6037 Fax: 90 312 362 5639 Email: leventyazicioglu{at}hotmail.com, Bilkent II Park Sitesi G-4 Blok 22/32, Ankara 06530, Turkey.
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ABSTRACT
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Destructed lung and pneumonectomy are associated with anatomic and physiologic changes that may interfere with the conduct of subsequent open heart surgery. Here we report a case of an autopneumonectomized patient who required open heart surgery. The preoperative, intraoperative and postoperative management of this patient was unique. Open heart procedures on patients with a single lung can be performed with acceptable operative mortality and morbidity.
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INTRODUCTION
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Destructed lung and pneumonectomy are associated with anatomic and physiologic changes that may interfere with the conduct of subsequent open heart surgery.1 Any patient who has a single lung from destructive lung is predisposed perioperatively to a much higher risk of cardiopulmonary complications. We report a case in which coronary artery bypass grafting was carried out 36 years after the patient had autopneumonectomy due to bronchiectasis.
A 51-year-old man, with a history of left destructed lung from cystic bronchiectasia at the age of 15-years-old, was admitted for evaluation of exertional chest pain. The patient was an ex-smoker of 360 packs per year and also hypertensive. Medications included enalapril maleate, nitrate derivates and acetyl salicylic acid (ASA). An electrocardiogram showed ischemia on anterior derivations, normal sinus rhythm with a heart rate of 80 beat–1 and breath rate of 16·min–1. The physical findings were normal except for left deviated heart sounds with no respiratory auscultation findings. The chest radiogram revealed absence of the left lung, hyperinflation of the right lung and mediastinal displacement (Figure 1
). Blood gases showed normal pH, mild hypercapnea (paCO2: 46 mm Hg) and hypoxemia (paO2: 70 mm Hg) without nasal oxygen. Pulmonary function tests revealed severe restrictive pattern. Preoperative pulmonary function was reduced: percent vital capacity was 65% and percent forced expiratory volume in 1 second was 79%. Coronary angiogram revealed severe proximal left anterior descending (LAD) and circumflex (Cx) lesion. The ejection fraction (EF) was 0.32 with apical and anterolateral hypokinesia. Attemped angioplasty was unsuccessfull and surgery was planned.
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Figure 1. The chest radiogram revealed absence of the left lung, hyperinflation of the right lung and mediastinal displacement.
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The patient was started on a program of vigorous chest physiotherapy, spirometry and bronchodilator therapy before operation. At the time of operation, pulmonary artery pressure was 35/15 mm Hg, pulmonary capillary wedge pressure 8 mm Hg, central venous pressure 7 mm Hg and cardiac index was 2.8 L·min–1·m–2. After median sternotomy, the heart was noted to be markedly displaced into the left hemithorax and was rotated in a clockwise direction placing the right atrium more anteriorly. The right lung crossed the midline and occupied the anterior mediastinum. The inferior vena cava was in the midline at the level of the diaphragm. LAD and Cx arteries were inaccessible with off-pump technique due to cardiac displacement. Aorta and right atrial cannulation was performed without difficulty. The patient underwent coronary artery bypass grafting with left radial artery (LRA) to LAD and saphenous vein graft (SVG) to circumflex system. Left internal mammary artery (LIMA) was not harvested. The heart was protected by continuous antegrade-retrograde blood cardioplegia. Topical cooling for myocardial preservation was not used. No difficulties were encountered during or after cardiopulmonary bypass. Fluid administration was restricted during the perioperative period. The patient was ventilated for 15 hours postoperatively and then extubated without difficulty. The postoperative course was uneventful. Vigorous chest physiotherapy, spirometry and bronchodilator therapy was continued postoperatively. Postoperative blood gases were similar to preoperative values. The patient was discharged on the eighth postoperative day with ASA, diltiazem and bronchodilator medications. The patient was asymptomatic in the second postoperative year.
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DISCUSSION
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Patients with a single lung are predisposed perioperatively to a much higher risk of cardiopulmonary complications. Even frequently encountered consequences of surgery such as atelectasis, congestion or nasocomial infection could lead to lethal outcomes in these patients.1 Pneumonectomy or lobectomy results in a decrease in vital capacity, with associated changes in oxygenation and carbon dioxide exchange. Anatomic changes alter the relationship in the thoracic cavity.2 The impairment in pulmonary function may cause pulmonary reserve to be minimal and changes in the ventilation perfusion ratios may result in a severe derangement in oxygenation.
This case was autopneumonectomized due to cystic bronchiectasis. Preoperative pulmonary function tests revealed severe impairment in ventilatory function, with no change after the physiotherapy and bronchodilator administration. However the patient had an active lifestyle, which may be explained by the long adaptation period. In this setting, standard pulmonary function tests may not have accurately reflected the patient’s status. Measuring the diffusion capacity for carbon monoxide and pulmonary vascular resistance, and determination of the maximal oxygen consumption during exercise may be a useful method other than standard pulmonary testing.3
Some authors have reported cannulation difficulty for these patients due to changes in the normal anatomic relationship but we had no such difficulty in this case. Routine use of internal mammary artery (IMA) grafts for these patients is of concern. A recent study indicates that the use of one or two IMA grafts does not increase respiratory dysfunction compared to the use of vein grafts. The pneumonectomized patients who had IMA grafts did not have a higher incidence of respiratory failure compared to patients who did not.4 However, it is prudent to avoid IMA harvest on the side of the intact lung to prevent phrenic nerve injury. We preferred LRA and SVG as graft material because of the younger patient age. Due to severe cardiac displacement and rotation, LIMA was not harvested as it could not be reached over the hyperinflated right lung and may have been kinked.
During both the preoperative and postoperative period, aggressive physiotherapy, early postoperative mobilization, and bronchodilator therapy are helpful. Steroid therapy may be added if needed.
The patient should be ventilated with low pressure to avoid barotrauma. Forced diuresis is recommended to reduce lung water content and colloid solutions are preferred for volume replacement. Minimizing the infusion of blood products will reduce the likelihood of adult respiratory distress syndrome (ARDS).3 Patients must be extubated as early as possible to avoid complications of prolonged intubation: pulmonary complications such as pneumothorax and re-intubation are more common in these patients. Our patient was extubated and mobilized on the first day which is early in comparison to the literature. This may be attributed to the patient’s younger age. Perioperative fluid management should be guided using accurate estimation of left ventricular preload by measuring the pulmonary capillary wedge pressure or the left atrial pressure.2
Phrenic nerve injury, which is a particularly serious complication for single lung patients, may result from topical cooling of the heart. Alternately, it may be caused by IMA dissection, as most of the blood supply to the phrenic nerve is supplied by IMA and IMA dissection renders the ipsilateral phrenic nerve more sensitive to hypothermic damage.5 Normothermic cardiopulmonary bypass with warm blood cardioplegia is suggested.3 We used mild hypothermic cardiopulmonary bypass with continuous antegrade-retrograde isothermic blood cardioplegia.
In conclusion, with optimal preoperative, intraoperative and postoperative management, it appears that open-heart procedures on patients with destructive lung disease can be performed with an acceptable operative mortality and morbidity.
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REFERENCES
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- Diab KA, Khatib MF, Obeid M, Jamaleddine GW. Coronary artery bypass grafting after pneumonectomy. Eur J Cardiothorac Surg 2001;19:362–4.[Abstract/Free Full Text]
- Berrizbeitia LD, Anderson WA, Laub GW, McGrath LB. Coronary artery bypass grafting after pneumonectomy. Ann Thorac Surg 1994;58:1538–40.[Abstract]
- Ferguson MK, Little L, Rizzo L, Popovich KJ, Glonek GF, Leff A, et al. Diffusion capacity predicts morbidity and mortality after pulmonary resection. J Thorac Cardiovasc Surg 1988;86:894–900.
- Benjamin JJ, Cascade PN, Rubenfire M, Wajszczuk W, Kerin NZ. Left lower lobe atelectasis and consolidation following cardiac surgery: the effect of topical cooling on the phrenic nerve. Radiology 1982;142:11–4.[Abstract/Free Full Text]
- O’Brien JW, Johnson SH, VanSteyn SJ, Craig DM, Sharpe RE, Mauney MC, et al. Effects of internal mammary artery dissection on phrenic nerve perfusion and function. Ann Thorac Surg 1991;52:182–8.[Abstract]
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