Postoperative Care of the Thoracic Patient

Introduction

Anesthesiologists are responsible for the management of the surgical cases not only during the intraoperative stage, but rather through the entire perioperative period. In the multidisciplinary context of perioperative medicine, anesthesiology is an important component in addressing the challenges from all practical, financial, and scientific points of view. Providing anesthesia to thoracic procedures is probably the prime example within the field of anesthesiology to have a crucial responsibility as a perioperative medicine physician. In general, the postoperative care of thoracic surgical patients is controlled by the intensive care unit (ICU) anesthesiologists either exclusively or as part of a multidisciplinary team with thoracic surgeons and pulmonologists. This chapter aims to review the postoperative care of the thoracic surgical patient. Postoperative complications, postoperative analgesia, as well as the postoperative part of the enhanced recovery after surgery (ERAS) protocol are discussed in Chapter 53 of the book.

In recent years, there have been significant advances in surgery, anesthesia, and intensive care techniques; however, thoracic surgery is still associated with a high incidence of postoperative complications recently reported, as being 27%. That high complication rate can be attributed to the fact that patients who were not surgical candidate decades ago are now offered major resections.

To decrease the high incidence of complications, enhanced recovery after thoracic surgery (ERATS) has been reported as a possible approach : these recommendations should be considered as a very promising pioneer step with a beneficial philosophy, but it should be underlined that they are based rather on strong recommendations than scientific evidence; therefore it is not surprising that the ERAS pathway is available in different protocols, with similar, but not the same recommendations, from different centers in different countries.

As a matter of fact, there are still very few obvious evidences to support any suggestion for possible challenges of the postoperative care after thoracic surgery.

However, the philosophy of ERAS is very appropriate in that all the stages of the perioperative period, namely preoperative evaluation and preparation, intraoperative management, and postoperative care should focus on enhanced recovery with decreased complications. We want to underline as an important note that enhanced does not mean necessarily fast.

Location and Structure of Postoperative Care: Intensive Care Unit, High-Dependency Unit or Postanesthetic Care Unit?

There are still no clear cut criteria for deciding whether to send the patient to the ICU or the postanesthetic care unit (PACU). In the past, patients post thoracotomy were almost routinely sent to the ICU. However in recent years, it is progressively difficult to find available ICU beds which are more expensive but not necessarily more beneficial. In fact, it has been shown that although elective transfer to the ICU has reduced the total morbidity and frequency of complications it has not changed the mortality rate (7.3% vs. 7.3%); moreover, elective transfer to the ICU has caused a longer hospital stay. The increasing quality of the PACUs has ensured a cost-effective and reliable alternative for postoperative admission.

The current trend is to move away from ICU admission and toward PACU or high dependency units (HDUs). In most institutions patients who undergo pneumonectomy, esophagectomy, or tracheal resection, are admitted to the ICU. In a recent retrospective study with 451 patients who underwent video-assisted thoracoscopic surgery (VATS) lobectomy, it has been shown that in selected patients (except: chronic obstructive pulmonary disease [COPD], nonstage I cancer, multiple port VATS, and age ≥60 years), selective intensive monitoring in the general ward—with the motto routine intensive monitoring but not routine intensive care—was safe and feasible without a poor outcome. Well-equipped units with appropriate monitoring would be a reasonable consideration when choosing the postoperative care location.

Preoperative criteria for transferring a patient to the ICU will depend on the patient’s medical condition, the type and the extent of the surgical procedure, and the hospital organization. We propose that a standardized preoperative prediction of whether the patient will be sent to the ICU or the PACU will help to establish a more appropriate organization of patient care. An interesting recent study has shown that patients who had an unplanned admission to ICU had higher mortality (29% vs. 0.03%).

How Helpful Are the Scoring Systems to Predict the Postoperative Status Preoperatively?

In general, three factors affect the decision of the location of the postoperative care: patient-related risks (whereby modifiable and nonmodifiable factors should be evaluated), surgical risks, and intraoperative events which are usually unexpected.

Some patient-related factors, such as age over 70 years, American Society of Anesthesiologists—score of 3 or more, fibrotic lung disease, or preoperative neoadjuvant chemotherapy are generally considered as potential indications for ICU admission. ^, Surgical procedures, such as pneumonectomy, tracheal and bronchial resection, esophagectomies, lung volume reduction, and transplantation are considered (not exclusively) as high-risk operations.

The difference between modifiable (e.g., smoking) and nonmodifiable factors (e.g., age) is the most clinically relevant measure; preoperative interventions on modifiable factors may decrease the need for ICU treatment. Some factors (e.g., preexisting lung disease, obesity, comorbidities, such as cardiovascular diseases, hypertension, diabetes mellitus) are partly modifiable. To achieve improvements in modifiable and partly modifiable factors, preoperative habilitation/prehabilitation programs have been shown to have a positive impact on the occurrence and severity of postoperative complications after thoracic operations by minimally invasive surgery. From this point of view it can be argued that the postoperative care of the thoracic patients starts in the preoperative period (see Chapter 9 ).

Scoring systems and risk factor definitions have been reported in several studies and reviews, can be helpful in defining the composite of patient-related surgical risks and provide some objective criteria regarding the location of postoperative care. Although it can differ among different centers, the overall recommendations of different scoring systems regarding the decision for sending the patient to ICU are:

• >5 points in the Surgical Mortality Probability Model (S-MPM)

• ≥3 points in the Revised Cardiac Risk Index

• >2.5 points in the Thoracic Revised Cardiac Risk Index (ThRCRI)

• ≤5 points in the Surgical Apgar Score.

• >45 points in the ARISCAT Score.

The ARISCAT study has reported a risk score for the development of postoperative pulmonary complications (PPCs) includes seven independent risk factors, both patient-related and surgical risk factors, that contributed equally to global risk and has been shown to have a predictive power. This scoring system is being used for several studies and clinical practice today.

Yet, there is still a big grey zone regarding the decision of the location of postoperative care of thoracic patients, because:

• 1

  First, the scoring systems were not originally defined for this purpose.

• 2

  Even in high-volume centers, a high number of patients unexpectedly become candidate for ICU admission because of intraoperative (e.g., longer duration of operation, longer duration of one-lung ventilation [OLV], excessive blood loss, and air leak) or postoperative (e.g., respiratory insufficiency, air leak, and atelectasis) factors.

• 3

  By calculating the balance between ICU versus PACU, incidence, and cost of readmission to ICU, and also failure to rescue of PPCs should also be taken in account. An important advantage of high-volume centers compared with the ones with less thoracic operations is that they have the resources and experience to address these problems.

• 4

  Local conditions play a very important role: the postoperative admission criteria for various institutions differ based on their individual preferences and organization schemes. Numerous reasons, such as the number and experience of nurses and health personnel, the ratio of postoperative patients/ICU beds, the conditions of PACU influence different hospitals’ decision to transfer patients, with the same preoperative conditions and similar surgical procedures, to the ICU or the PACU.

Management of Chest Tubes

Chest tubes are considered mandatory in all intrathoracic operations. Therefore the physician should be familiar with proper management of the thorax drainage, diagnosis, and treatment of its complications. Chest tubes remove air (ventral or cranial placement) and/or fluid (dorsal or caudal placement). Thus the physician’s goal is to monitor, prevent, or treat air leaks and excessive pleural drainage.

Although digital chest drainage systems are being used increasingly since approximately 10 years, the principle of the classical 3-bottle chest tube drainage system ( Fig. 26.1 ) should still be mastered by the clinician dealing with a postthoracotomy patient.

The introduction of ERATS protocols has again shown the controversies in the management of chest tubes. There are several issues regarding the chest tube management:

• 1

  Suction Versus No Suction?

  The air from the pleura can be sucked passively (with a water seal) or actively (with a wall suction). ERATS protocol sufficiently summarizes the pros and cons of both suction and the so-called water seal. The relationship between the suction approach and clinical outcome is relatively weak that it can be easily biased by other components of the protocol of chest tube management. Yet, there are some common approaches:

  • a

    As a general rule, routine use of negative suction is to be avoided, and should be limited to persisting air leakages and nonexpandable lungs

  • b

    The negative pressure should not exceed 15 to 20 cm H ₂ O.

  • c

    After pneumonectomy, no negative pressure should be applied because of the risk of mediastinal shift.

• 2

  Drainage and Removal

  After a thoracic procedure, blood drainage should be carefully monitored especially in the early phase, and excessive drainage should signal an emergency alarm to immediately contact the surgical team. There have been empirically determined thresholds (e.g., 200 or 250 mL/day) for chest tube removal, however these dogmas have been refuted with stronger studies showing that the chest tubes can be removed if the drainage is <450 mL/day as long as there is no air leak or cerebrospinal fluid, chyle, or blood in the fluid. Even a high drainage of 500 mL/day following VATS lobectomy resulted in an incidence of clinically relevant recurrent effusions, that needing drainage or aspiration, in only 2.8% of patients.

• 3

  Other Relevant Issues

  • Any discrepancy between chest x-rays (or lung ultrasonography) and chest tubes output, may indicate failing thorax drainage because of tube blockage with a kink, blood clot, or suction failure.

  • Chest tubes should never be clamped during patient transport because of the risk of pneumothorax.

  • During removal of the chest tube, a Valsalva maneuver should be applied (preferably after full expiration instead of full inspiration) to ensure positive intrathoracic pressure—combined with rapid removal—to prevent pneumothorax.

  • Digital chest tube systems, commercially available since approximately 10 years, have been shown to reduce the risk of prolonged air leak, shorten the duration of both chest drainage and hospital stay compared with the traditional chest drainage system ^, ( Fig. 26.2 ).

    

Specific Monitoring Tools

Routine monitoring after thoracic surgery outside the ICU consists of continuous pulsated oximetry (SpO2) and chest x-ray (CXR) in predetermined certain times. However, this paradigm of routine CXR is subject to change: studies examining the advantages of routine daily CXR versus selective clinical evaluation were not able to report any change in mortality rate, hospital length of stay, or adverse events on the basis of schedule CXR, with the only exception in hypoxic patients. On the other hand, selective CXR only caused by clinical suspicion of a potential problem carries the risk of missing the initial phase of pulmonary complications. Low-radiation dose computer tomography (CT) allows reliable evaluation of pulmonary edema, but does not appear to be a widespread alternative because of the high cost, the risk of transport, and radiation exposure. Lung ultrasound (LUS) appears to solve the dilemma, in addition to its other advantages.

Another challenge is the decision about optimal fluid management, as the fluid therapy has been a classical problem especially in the intra- and postoperative period of thoracic surgery. New techniques not only help to determine whether to give more fluids, they can also help to monitor right ventricle function.

Lung Ultrasound as a New Tool (See Chapter 54 )

LUS is a quick, inexpensive, easy-to-use and—importantly—­reliable imaging modality. It can diagnose cases of possible or undetected pneumothorax in CXR ( Fig. 26.3 A); as well as pulmonary edema, pleural effusion, subcutaneous emphysema, and pneumonia ( Fig. 26.3 B–D). In conjunction with limited information from cardiac or ­vascular ultrasound, LUS aids diagnosis of pulmonary embolism.

The very basic knowledge of LUS evaluation has been defined by Lichtenstein. The pioneer of the protocols of this approach: in normal lung tissue, the interlobular septa are not detected by ultrasound and the pleural lines yield horizontal repetition artifacts, which have been termed the A-lines ( Fig 26.3 E). When the subpleural alveoli become edematous in the setting of increased extravascular lung water (EVLW), the resulting mixture of air and fluid yields the pathologic B-lines by ultrasound. These B-lines represent reverberation artifacts arising from the air-fluid interface between the fluid-filled and aerated alveoli (see Fig. 26.3 B). There is a linear correlation of the numbers of B-lines and increasing EVLW that reaches from interstitial edema showing four to eight B-lines to severe states of the alveolar-interstitial syndrome (AIS) with the confluence of multiple B-lines to the appearance of white lung (see Fig. 26.3 B and F). Sonographic appearance of AIS can also help to differentiate its possible causes, whereby a uniform distribution pattern of B-lines, with normal lung sliding and a high incidence of homogeneous appearing pleural effusions indicates left atrial hypertension and increased hydrostatic pressure. While in acute respiratory distress syndrome (ARDS) there are increased amounts of B-lines, seen in combination with pleural line abnormalities, lack of lung sliding, uneven tissue patterns like spared areas, consolidations, such as lung pulse and air bronchograms.

Using transthoracic echocardiography (TTE), ventricular function can be evaluated. Especially right ventricular functions during and after thoracic surgery has been considered to be very difficult, and also often underestimated.

Furthermore, the evaluation of the diaphragm with ultrasonography (DUS) may provide additional benefits to the clinician. A diaphragmatic dysfunction has been documented after thoracic surgery, as a condition that contribute to an increase in postoperative pulmonary complications. ^, The diaphragmatic ultrasonography is a noninvasive method which can be performed at the bedside. For this purpose, the diaphragm is evaluated in two different ways. These include the functional evaluation of the diaphragmatic excursion (DE) and the diaphragmatic thickening (DT) fraction ( Fig. 26.3 G and H). In a study where DE was used for the functional evaluation of the diaphragm, it has been shown that the diaphragmatic dysfunction detected within the first 24 hours was associated with the PPC occurring within the first 7-day period. Spadaro et al. ­in a ­prospective study enrolled 75 patients undergoing VATS versus those undergoing thoracotomy. Diaphragmatic dysfunction was defined as a diaphragmatic excursion less than 10 mm. The ultrasound evaluations were carried out before (preoperative) and after (i.e., 2 hours and 24 hours postoperatively). The incidence of postoperative diaphragmatic dysfunction at 24 hours was higher in the thoracotomy group as compared with VATS group (83% vs. 55%, respectively). Patients with diaphragmatic dysfunction on the first day after surgery had higher percentage of PPCs (odds ratio = 5.5; 95% confidence interval [CI], 1.9–16.3; P = .001). Although there are few studies addressing the issue, the value of the available evidence indicates the significance of DUS and the need for further studies.

Consequently, LUS should be considered as a beneficial diagnostic tool in the practice of postoperative thoracic surgery:

• 1

  Compared with CXR, it is more specific and sensitive in diagnosing pathologic entities.

• 2

  It can monitor EVLW, which can be challenging especially in the perioperative period of thoracic surgery; and differentiate in some cases between the possible causes of EVLW increase.

• 3

  By switching to TTE, it can monitor the functions of right ventricle.

• 4

  Finally, ultrasound can be used as a guide in procedures like vascular catheterization and nasogastric tube replacement.

It should be taken in account that for the patient undergoing thoracic surgery, abnormal anatomy because of preexisting diseases or changes because of surgery can limit the diagnostic value of LUS; preoperative LUS evaluation can be a rational approach to eliminate this limitation.