9    Complications and Their Prevention

Medical thoracoscopy/pleuroscopy (MT/P) is a safe and effective modality in the diagnosis and treatment of several pleuropulmonary diseases if certain standard criteria are fulfilled. Complications of thoracoscopy were well known to earlier phthisiologists. The advantages of the technique should be weighed against the discomfort to the patient and the slight potential for morbidity and mortality. Although the risks are low, it is important that adequate precautions are taken, including the recommended technical procedure as well as monitoring of cardiac and hemodynamic parameters and oxygen saturation during the procedure.

As for all conscious sedation protocols, patients undergoing MT/P should refrain from eating and drinking 6-8 hours before the procedure to reduce the risk of aspiration.

Complications that may be associated with MT/P can be separated into those that may occur before, during, or after the procedure (Table 9.1). These potential complications, although rare, will be described in detail because their knowledge and their prevention will enable the thoracoscopist/pleuroscopist to avoid them in great part.

Prethoracoscopic/Prepleuroscopic Complications

Air Embolism

The most serious complication of pneumothorax induction is air or gas embolism that can occur during pneumothorax induction. Fortunately it happens very rarely (< 0.1%) and can be prevented if appropriate precautionary measures are taken (see “Access to the Pleural Space,” Chapter 11, p. 78 ff.). However, in older reports the frequency of air embolism in therapeutic pneumothorax, often performed under less-optimal conditions, varied between 0.1% and 0.5% (Schmidt 1938). In more than 3000 diagnostic thoracoscopies, one of the authors (R.L.) observed only one case of transient neurological abnormality, presumably due to cerebral gas embolism (CO₂ was used for pneumothorax induction) (Brandt et al. 1985). Otherwise, incorrect needle position during filling with a pneumothorax apparatus can produce subcutaneous emphysema.

In the presence of effective local anesthesia (see “Technique of Local Anesthesia,” Chapter 11, p. 84 ff.) and well-titrated sedation, little discomfort is felt, even when instruments with a larger diameter (11 mm) are used. When biopsies of the parietal pleura are taken, patients must be warned of the associated brief discomfort, and should be advised that they may cough when the lung is biopsied.

Prior to talc insufflation, which may be painful, additional analgesics (alternatively intrapleural lidocaine spray) should be given to the patient (see “Technique of Thoracoscopic Talc Pleurodesis,” Chapter 11, p. 92 ff.). Although an average total dose of 600 mg of lidocaine appeared safe in bronchoscopy (Langmack et al. 2000), the total dose should be limited to approximately 300 mg, which should be sufficient for local anesthesia. Methemo-globinemia is an uncommon complication of topical anesthetics, particularly of lidocaine (Weiss et al. 1987).

Hypoxemia

The procedure may cause hypoxia for several reasons: depression due to the anesthesia, healthy lung in the lateral decubitus position, and collapse of the investigated lung due to the induced pneumothorax. Oxygen saturation usually decreases only insignificantly during the procedure (Oldenburg and Newhouse 1979; Faurschou et al. 1983; Cho et al. 2000). Nasal oxygen may be provided pro-phylactically.

Hypoventilation

Some advocate the simultaneous cutaneous measeurement of carbon dioxide tension (P_cCO₂), since significance hypoventilation might occur due to the sedation (Chhajed et al. 2005).

Cardic Arrhythmias

Except for a slight sinus tachycardia, cardiac arrhythmias are rare (Faurschou et al. 1983, Cho et al. 2000).

Hypotension

With the removal of large pleural effusions, one should be alert to the development of hypotension because of the associated considerable volume loss. Some authors recommend atropine (0.25-0.8 mg) to suppress vaso-vagal reflexes (Boutin et al. 1991; Rodriguez-Panadero 2008), but it is not clear whether atropine is necessary as routine premedication (Cho et al. 2000; Loddenkemper 2000).

During the procedure, cardiorespiratory functions should be monitored by electrocardiography (ECG), measurement of blood pressure, and continuous oximetry. Many complications such as benign cardiac arrhythmias, low-grade hypotension, or hypoxemia can be prevented by administration of oxygen and intravenous fluids.

Hemorrhage

A major concern often expressed regarding MT/P is the risk of bleeding and the need for surgical back-up. In this regard, the reported incidence of significant bleeding—i.e., requiring transfusion or surgical intervention—is exceedingly low. Superficial bleeding at the site of introduction ceases as a result of compression following the introduction of the trocar. If hemorrhage occurs after the taking of biopsies, this is in general only very slight and ceases spontaneously if the suggested precautions are observed. If bleeding does not stop or if an intercostal vessel has been biopsied inadvertently, the bleeding area should be compressed and/or cauterized with electrocoagulation (see “Biopsy Techniques,” Chapter 11, p. 89 ff.). Contraindications for pulmonary biopsy are suspicion of arterio-venous pulmonary aneurysm and highly vascularized pulmonary lesions.

Injury to Lung or Other Organs

Injury to the lung and other organs is almost always avoided by proceeding carefully, in particular when adhesions between the chest wall and the lung are present. It has to be kept in mind that the diaphragm is elevated in the recumbent position, and it is important to observe the suggested sites of introduction of the cannula to avoid dangerous areas (see “Selecting the Point of Entry,” Chapter 11, p. 78). One fatal complication caused by injury to an enlarged leukemic spleen has been reported (Dijkman 1989). One of the authors (R.L.) performed an unintended “pericardioscopy” in a case where the pericardium was fixed to the left anterior chest wall by a small postinflammatory adhesion (without further complication).

Postthoracoscopic/Postpleuroscopic Complications

Reexpansion Pulmonary Edema

This rare possibility may arise in particular when a large amount of pleural fluid has caused an atelectatic lung, when a stiff or trapped lung is present, in the case of a complete endobronchial obstruction, or in the case of a long-lasting pneumothorax. In these situations, negative pressure through the drainage tube should be applied very cautiously, and the patient should be observed closely (see also “Knowledge of the Pathophysiology of the Pleura,” Chapter 10, p. 67 ff. and “Chest Tube Care,” Chapter 11, p. 95 ff.).

Pain

Analgesics should be given as needed. The correct position of the chest tube should be monitored.

Postoperative Fever

Low-grade fever (37.5-38.5 °C), which often occurs in the following days, does not signify an infection but rather an inflammatory tissue reaction (Viskum 1989). Higher fever and stronger systemic reactions are noted after talc poudrage (Froudarakis et al. 2006).

Wound Infection

Wound infection as a complication is not mentioned in any study. It does of course occur, but must have been considered too insignificant to be mentioned (Viskum and Enk 1981). The chest tube site should be regularly inspected and, if necessary, dressings should be changed.

Empyema

Postthoracoscopic empyema is a rare complication, but occur after a long drainage duration or due to a born-chopleureal fistula. It has been reported in 12 cases in three studies comprising 652 patients (2%) (Viskum and Enk 1981).

Subcutaneous Emphysema

Subcutaneous emphysema is usually only slight and resolves spontaneously if the suction drainage functions appropriately.

Persisting Pneumothorax

Here, first it must be checked whether the chest tube drainage functions properly. Otherwise, this complication is most likely to occur when lung biopsies are taken from a fibrotic lung (see “The Place of Medical Thoracoscopy/ Pleuroscopy in the Diagnosis of Diffuse Lung Diseases,” Chapter 3, p. 46 ff. and “Biopsy Techniques,” Chapter 11, p. 89 ff.), which may necessitate additional chest tubes. In cases of trapped lung or of pneumothorax with persisting pleuropulmonary fistulas, the appropriate measures have to be taken, as described in the sections on “Options in the Local Treatment of Pleural Effusions Including Thoracoscopic Talc Pleurodesis,” Chapter 3, p. 35 ff. and “The Place of Medical Thoracoscopy/Pleuroscopy in the Management of Pneumothorax,” Chapter 3, p. 41 ff., respectively.

Prolonged Air Leakage

Prolonged air leakage is a potential complication after lung biopsies have been taken, particularly with a stiff or trapped lung. Therefore, taking biopsy samples of honeycomb lung from end-stage pulmonary fibrosis should be avoided as it contributes to a high incidence of broncho-pleural fistulae with prolonged suction. Biopsies should also be avoided in cases of bullous lung disease. However, air leakage can also occur in patients with necrotic tumor nodules, especially those with prior chemotherapy, even if no biopsies of this area have been taken (Antony et al. 2000). In these cases very gentle suction should be applied through the chest tube (see “Chest Tube Care,” Chapter 11, p. 94 ff.). Empyema with a bronchopleural fistula needs appropriate surgical intervention (see the section on “Parapneumonic Effusions and Pleural Empyema,” Chapter 3, p. 31ff.).

In cases where pleural fluid is still produced in a considerable amount after the procedure without performance of talc poudrage, the usual pleurodesis procedures are indicated (see “Chest Tube Thoracostomy with Chemical Pleurodesis,” Chapter 3, p. 38). Initial failure of thoracoscopic talc pleurodesis (poudrage) can occur as a result of suboptimal techniques or inappropriate patient selection (e.g., a patient with trapped lung or mainstem bronchial occlusion). When initial pleurodesis fails, several alternatives may be considered. Repeat pleurodesis may be performed either with instillation of sclerosants through the chest tube or by repeat MT/P and talc poudrage (Antony et al. 2000). Other alternatives are described in “Options in the Local Treatment of Pleural Effusions Including Thoracoscopic Talc Pleurodesis,” Chapter 3, p. 35 ff. Recurrence after pleurodesis is unusual with talc but does occur occasionally. In these cases, one of the other options that have been mentioned should be tried. If the patient is receiving corticosteroid therapy, the drug should be stopped or the dose reduced if possible because of concerns of decreased efficacy of pleurodesis (Kennedy et al. 1994).

Early Complications after Talc Pleurodesis

Talc pleurodesis via either chest tube slurry or thoracoscopic insufflation of dry talc, has been reported to induce acute lung injury and the acute respiratory distress syndrome (ARDS) (Kennedy and Sahn 1994; Campos et al. 1997; Rehse et al. 1999; Light 2000; Sahn 2000). The toxic effects of talc are hypothesized to be mediated primarily by smaller talc particles < 15 μm. A small prospective trial compared a mixed talc preparation with 50% of particles less than 10 μm and a graded talc preparation with < 50% particles smaller than 20 μm and demonstrated that the mixed talc caused a greater A-a (alveolar-arterial) gradient and systemic inflammatory response (fever and C-reactive protein) than did graded talc (Maskell et al. 2004). Meanwhile, a large prospective multicenter study in more than 500 patients with malignant pleural effusion has shown that the use of size-calibrated talc (Steritalc with a mean particle size of 24.5 μm and only 11 % having size < 5 μm) prevents the development of ARDS, probably due to a substantially reduced systemic distribution (Janssen et al. 2007). Talc poudrage causes more fever and systemic inflammatory reactions than does thoracoscopy alone (Froudarakis et al. 2006).

Late Complications after Talc Pleurodesis

Potential long-term sequelae such as reduced pulmonary function and cancer have been excluded by long-term follow-up studies that confirmed the safety of talc (Lange et al. 1988; Cardillo et al. 2007; Györik et al. 2007; Hunt et al. 2007; Noppen 2007).

Seeding of Chest Wall by Tumor Cells/ Implantation of Tumor Cells

To prevent the potential late complication of contamination of the entry site(s) by tumor cells, particularly in mesothelioma cases, prophylactic radiotherapy 10-12 days after MT/P has been recommended (Boutin et al. 1995b), although this is controversial (Low et al. 1995; Bydder et al. 2004; O’Rourke et al. 2007; Davies et al. 2008).

Mortality

Mortality is reported to be an extremely rare event of MT/ P with only one death in 8000 cases, for a mortality rate of 0.01 (Viskum and Enk 1981); in another series reviewing 4300 cases, the mortality rate was 0.09% (Boutin et al. 1981b). The mortality rate of 0.24% for MT/P is comparable to that reported for transbronchial biopsies (0.22-0.66%) (Boutin et al. 1985a).

However, in the prospective multicenter study on medical thoracoscopic talc poudrage in malignant pleural effusions, published in The Lancet in 2007, 11 out of 558 patients died within 30 days after the procedure. Thus the 30-day mortality (2%) was higher than in the above articles. This is explained by the limited life expectancy and serious co-morbidity of these patients, in a small proportion of whom postthoracoscopic complications and mortality can be expected (Janssen et al. 2007). All causes of death, listed in detail, were due to severe co-morbidities. Serious adverse events were observed in seven cases (1.24%): two patients developed a reexpansion edema, one had a transient cardiogenic pulmonary edema, one had an acute respiratory insufficiency due to unexplained contralateral pneumothorax on the day of thoracoscopy, one had a pulmonary embolism on day 8, one developed pneumonia with high fever, and one developed nonpulmonary sepsis. No acute respiratory distress syndrome (ARDS) was observed.

Dijkman, who, between 1976 and 1987, performed MT/P in 65 patients suffering from pulmonary complications in immunosuppression of various non-HIV origins reported two fatal complications (3%), one following injury of an considerably enlarged leukemic spleen and one following uncontrollable bleeding after several deep parenchymal lung biopsies at the same site. Fifteen of these severely ill patients, who already had compromised respiratory function, needed postthoracoscopic mechanical ventilation (Dijkman 1989).

Menzies and Charbonneau in their study of 102 patients registered a major complication rate of 1.9 % including ventricular tachycardia responding to resuscitation, subcutaneous emphysema, and persistent air leakage, while the minor complication rate was 5.5% including transient air leakage, fever, and minor bleeding at the biopsy site (Menzies and Charbonneau 1991).

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