Link to Article
Quote:
Pneumopericardium associated with face-mask continuous positive airway pressure
Robet C. McEachern
This is an uncommon case of a patient who developed pneumopericardium while being treated with face-mask continuous positive airway pressure (CPAP) for hypoxic respiratory failure following a coronary artery bypass graft surgery. A pneumopericardium detected by chest radiograph resolved completely after discontinuation of face-mask CPAP. Possible mechanisms that may have been involved in this unusual complication are reviewed.
(CHEST 1997; 112:1441-43)
Key words: barotrauma; continuous positive airway pressure; coronary artery bypass graft; pneumopericardium
Abbreviations: CABG=coronary artery bypass graft; CPAP=continuous positive airway pressure
Noninvasive spontaneous continuous positive airway pressure (CPAP)is an effective and simple method to increase arterial oxygenation in patients with hypoxic respiratory failure. This prevents the need or delay for endotracheal intubation and assisted mechanical ventilation. A common and simple means of providing spontaneous CPAP consists of a continuous, high flow of gas with an expiratory resistance valve attached to a tight-fitting face mask. Like positive end-expiratory pressure through an endotracheal tube, spontaneous CPAP improves arterial oxygenation. Unfortunately, CPAP also suffers from the same disadvantage as positive end-expiratory pressure--a heightened risk of pulmonary barotrauma in the presence of acute lung injury or ARDS.[1] However, only two cases are reported in the literature as having an association of spontaneous CPAP with barotrauma such as pneumomediastinum and pneumothorax. In one patient with hypoxic respiratory failure, pneumomediastinum was observed following transtracheal aspiration for sputum culture but resolved spontaneously despite continued use of CPAP therapy.[2] In a case series, 1 out of 18 patients with Pneumocystis carinii pneumonia and hypoxic respiratory failure was noted to develop a pneumothorax during CPAP therapy.[3] Pneumopericardium from various causes has been reported in the literature;[4,5] however, as best as can be determined, the occurrence of pneumopericardium with the use of spontaneous noninvasive CPAP during hypoxic respiratory failure has never been reported.
A case is presented of a patient who developed hypoxic respiratory failure a few days after a coronary artery bypass graft (CABG) surgery. While being treated with face-mask CPAP, a pneumopericardium was detected by a chest radiograph, which completely resolved after discontinuation of face-mask CPAP. Possible mechanisms that could be involved in this unusual complication are reviewed.
CASE REPORT
A 65-year-old male veteran underwent a five-vessel CABG at the University Medical Center in Jackson, Miss. His postoperative course was complicated by prolonged mechanical ventilation. On the 7th postoperative day, he was extubated and placed on conventional face mask with 40% FI[O.sub.2] and intermittent CPAP of 5 cm [H.sub.2]O. On the 9th postoperative day, he was transferred back to the coronary care unit at the VA Medical Center in Jackson, Miss, for further postoperative management and observation. Upon arrival, the patient was alert but mildly dyspneic; his respiratory rate was 33 breaths per minute while using a conventional face mask with an FI[O.sub.2] of 40%. A physical examination disclosed bilateral coarse breath sounds on auscultation. His chest radiograph revealed mild reticular nodular hype infiltrates diffusely. The arterial blood gas values, with 40% Fl[O.sub.2], revealed a Pa[O.sub.2] of 44 mm Hg, a PaC[O.sub.2] of 34 mm Hg, and a pH value of 7.52. The FI[O.sub.2] was increased to 60% and the tight-fitting face-mask CPAP was increased to 10 cm [H.sub.2]O to maintain arterial oxygen saturation greater than 90% He continued to tolerate the face-mask CPAP and became less dyspneic. Twenty-four hours later, a routine chest radiograph revealed worsening bilateral infiltrates with two obvious radiolucent areas along both hear borders, suggesting pneumopencardium (Fig 1). The chest radiograph also showed a thin radiolucent area outlining the light mediastinum, suggesting possible pnemnomediastinum. The extent of the barotrauma was evaluated w th a CT scan of the chest which revealed extensive bilateral airspace consolidation and the presence of a pneumopericardium but no pneumomediastinum or pneumothorax (Fig 2).
[Figure 1-2 ILLUSTRATION OMITTED]
The patient appeared more dyspneic but remained hemodynamically stable, and results of a physical examination at that time were normal. The face-mask CPAP was promptly discontinued and the patient was then treated with 100% nonrebreathing conventional face mask. A bedside echocardiogram and catheterization of the right side of the heart revealed no obvious cardiac tamponade. We elected to closely monitor the patient during that time period with the intention of performing emergency pericar-diocentesis in the event of hemodynamic instability. Serial chest radiographs over the following 72-h period showed complete resolution of the pneumopericardium while bilateral infiltrates persisted (Fig 3). He developed respiratory distress, and intermittent CPAP was reinstituted after the patient declined endo-tracheal intubation and mechanical ventilation. He deteriorated, as manifested by worsening radiographs and hypoxemia, despite advancement to continuous face-mask CPAP and died the following day.
[Figure 3 ILLUSTRATION OMITTED]
DISCUSSION
Pneumopericardium, a form of barotrauma, refers to the presence of air within the pericardial sac, a condition that is much less common than either pneumothorax or pneumo-mediastinum. Pneumopericardimn results from mediastinal air dissecting at the reflection of the parietal to visceral pericardium near the ostia of the pulmonary veins.[6] This occurs more frequently in infants than in adults. This is probably due to the stronger adhesions between the pericardial layers in the adult, precluding communication between the pericardial space and the mediastinum.[7]
In mechanically ventilated pahents, there is an increased incidence of pulmonary barotrauma especially when there is an associated underlying pulmonary parenchymal process and high airway pressure.[8] It is possible that our patient developed alveolar disruption from severe acute lung injury, and spontaneous CPAP contributed to increasing the pressure gradient between alveoli and the bronchovascular sheath leading to pneumomediastinum and pneumopericardium. Furthermore, pneumopericardium resolved completely once the C2PAP was discontinued. Shawl and Chun[9] reported a case of pneumopericardium due to sternal dehiscence following CABG surgery leading to entry of air into the pericardial sac during inspiration. The reported patient did not have sternal dehiscence, hut the alteration of the normal mediastinal and pericardial structures during CABG surgery may have allowed air to enter directly into the pericardium from the mediastinum.
Radiographically, pneumomediastinum and pneumo-pericardium frequently are confused since they can occur concomitantly.[10] However, three signs on a chest radiograph can help in differentiating pneumopericardium from pneumomediastinum. These include a radiolucent halo of air partially or completely surrounding the heart but not extending superiorly to the attachments of the pericardium, a shift in pericardial air on a decubitus radiograph, and the absence of a continuous diaphragm sign. In this case, the initial chest radiograph showed a thin radiolucent area outlining the right mediastinum, suggesting pneumomediastinum, and two obvious radiolucent areas along the lateral borders of the heart, suggesting pneumopericardium (Fig 1). Pneumothorax was not evident on this chest radiograph. However, a CT seen of the chest to evaluate the extent of pulmonary barotrauma revealed only pneumopericardium (Fig 2).
Management of pneumopericardium is similar to that of pneumomediastinum. Surgical intervention, catheter drainage procedures, or both would be appropriate in patients with concomitant hemodynamie compromise. Also, these patients need to be observed closely since they are at high risk for other barotrauma complications. In this ease, the pneumopericardium resolved soon after the discontinuation of CPAP and initiation of treatment with high inspired oxygen.
This complication associated with face-mask CPAP during hypoxic respiratory failure is uncommon since no similar ease was found in the medical literature. In patients with severe lung injury, a greater awareness of the possible pulmonary barotrauma from spontaneous CPAP should be considered. Because of the possible asymptomatic presentation, a serial chest radiograph and hemodynamie monitoring should enable the physician to make an early diagnosis and to begin treatment as soon as possible.
REFERENCES
[1] Petersen GW, Baier H. Incidence of pulmonary barotrauma in a medical ICU. Crit Care Med 1983, 11:67-9
[2] Powner D, Snyder JV, Grenvik A. Altered pulmonary capillary permeability complicating recovery from diabetic ketoacidosis. Chest 1975; 68:253-56
[3] Gregg RW, Friedman BC, Williams JF, et al. Continuous positive airway pressure by face-mask in Pneumocystis carinii pneumonia. Crit Care Med 1990; 18:21-24
[4] de la Rubia L, Lopez-Herce J, Murga ML, et al. Spontaneous pneumopericardium in a teenager [letter]. Pediatr Cardiol 1994; 15:104-05
[5] Katzir D, Klinovsky E, Kent V, et al. Spontaneous pneumo-pericardium: case report and review of the literature. Cardiology 1989; 76:305-08
[6] Mansfield PB, Graham CB, Beckwith JB, et al. Pneumopen-cardium and pneumomediastinum in infants and children. J Pediatr Surg 1973; 8:691-99
[7] Hurd TE, Novak R, Gallagher J. Tension pneumopericardium: a complication of mechanical ventilation. Crit Care Med 1984; 12:200-01
[8] Gammon RB, Shin MS, Groves RH, et al. Clinical risk factors for pulmonary barotrauma: a multivariate analysis. Am J Respir Crit Care Med 1995; 152:1235-240
[9] Shawl FA, Chun PKC. Pneumopencardial tamponade post-coronary artery bypass sternal dehiscence Am Heart J 1982; 104: 160-63
[10] Semenkovich J, Freundlich IM. Abnormal thoracic air. In: Freundlich IM, ed. A radiologic approach to diseases of the chest. Baltimore: Williams & Wilkins, 1992; 186-98.
(*) From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Mississippi Medical Center, and VA Medical Center, Jackson, Miss.
Manuscript received February 19, 1997; revision accepted May 8. Reprint requests: Rajesh G. Patel, MD, Assistant Professor of Medicine, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Mississippi Medical Center, 2500 N. ST. Street, Jackson, MS 39216-4505
COPYRIGHT 1997 American College of Chest Physicians
COPYRIGHT 2004 Gale Group