Intraoperative use of a chest physiotherapy system during whole lung lavage for pulmonary alveolar proteinosis

Abstract

Pulmonary alveolar proteinosis (PAP) is a rare condition caused by the excessive alveolar accumulation of surfactant proteins. The current standard of care for removing these secretions is through therapeutic whole lung lavage (WLL). We describe two successful cases of bilateral WLL involving the novel use of the Vest™ chest physiotherapy system thereby avoiding the need for extensive changes in patient position in the intraoperative period. In brief, it involves the induction of general anesthesia followed by single-lung ventilation while simultaneously performing large volume lavages on the nonventilated lung. The washout was enhanced using the Vest™ system.

Introduction

Pulmonary alveolar proteinosis (PAP) is a rare clinical syndrome characterized by the intra-alveolar accumulation of surfactant material with minimal interstitial inflammation or fibrosis. The clinical course of the disease is variable and ranges from spontaneous resolution to progressive respiratory failure and death. Numerous treatment modalities have been tried and tested in the past few decades since the disease was first described by Rosen and colleagues [Rosen et al. 1958]. They range from corticosteroids and inhaled acetylcysteine to granulocyte–macrophage colony stimulating factor (GM-CSF), but no curative therapy is available to date. Whole lung lavage (WLL) has emerged as the current standard of care [Ramirez et al. 1965; Mazzone et al. 2001]. Traditionally WLL involves single lung isolation, instilling lavage fluid into each lung and encouraging complete washout by using manual chest physiotherapy and changes in patient position during washout.

We report an effective and successful modification of the WLL procedure using the Vest™ Airway Clearance Device (Hill-Rom, Batesville, IN) without any significant changes in patient position during the procedure. This method, in addition to being effective, also eliminates the risks of frequent change in patient position during WLL.

Methods

We obtained informed consent from the patients to report and present the cases in academic endeavors. No formal institutional review board (IRB) application was made for the two cases.

Case 1

The patient was a 43-year-old white female with an established diagnosis of primary PAP who was referred to the critical care anesthesia team to be evaluated for WLL. She had worsening dyspnea on exertion and a nonproductive cough for the past 2 years. The patient had a 20-packyear history of tobacco use. She did not have any occupational exposure to any specific agent. We did not have GM-CSF titers at the time of the lavage procedure. She did not have any other significant medical history. She was using her albuterol inhaler only as needed and bupropion to help her stop smoking.

Case 2

The patient was a 49-year-old African American male with a known history of primary PAP, first diagnosed about 6 years ago. This patient had undergone the traditional WLL procedure twice in the past. The patient had a history of hypertension, tobacco use of 30 packyears. We did not have GM-CSF titers at the time of the lavage procedure. He did not have any occupational exposure to any specific agent. The patient’s exercise tolerance had deteriorated over the last 6–8 months and was now able to walk about 200 yards before he had to rest. He was referred to the Critical Care Anesthesia team to be evaluated for WLL.

Procedure

Following a detailed preoperative evaluation both cases were considered suitable candidates for WLL. In the operating room the patients were premedicated with 2 mg of midazolam. The patient was positioned in the supine position, standard American Society Anesthesia (ASA) monitors and the Vest Airway Clearance device (Vest) was applied. Following pre-oxygenation for 3 minutes, general anesthesia was induced intravenously using propofol (2 mg/kg) and rocuronium (0.5 mg/kg). A left-sided double lumen endotracheal tube (size 37 F for the female patient and a size 39 F for the male patient) was placed without event and position was confirmed by fiberoptic bronchoscopy. Balanced general anesthesia was maintained using sevoflurane in oxygen and air. A radial arterial line and a pulmonary artery catheter via the right internal jugular vein were placed without complication. After reviewing the chest X-rays, the radiologically worse lung was isolated.

The lavage fluid used was specifically prepared by the pharmacy for the procedure and composed of 0.9% normal saline (NSS) with sodium bicarbonate (4 mEq/l) buffered to a pH of 7.45 and prewarmed to a temperature of 37°C. An arbitrary maximum of 10 liters of lavage fluid per lung was decided upon prior to the start of the procedure. A major intraoperative goal was to prevent hypoxemia and since we had limited experience with this procedure using the Vest, we decided to use a maximum of 10 l of lavage fluid per lung.

One liter of lavage solution was allowed to flow slowly into the isolated lung by gravity. After about 500 ml, the Vest was activated and the chest percussions were initiated and continued for 5 minutes at a time. The Vest Airway Clearance System is a chest percussion device consisting of an air-pulse generator attached to an inflatable vest. Once we started the Vest device, we increased it to the maximum oscillations within about a minute of initiating therapy. When active, the pressure in the vest increases and decreases up to 25 times per second, thereby applying rapid oscillations to the patient’s chest wall and help with mobilizing secretions (Figure 1). After the device was in use for about 5 minutes, the percussion was stopped and the lavage fluid was drained by gravity into a collection canister. The color, volume and appearance of the drained fluid were noted (Figure 2). The same procedure was repeated with the next bag of lavage solution. We visually ‘guesstimated’ the clearance in the collection canisters and stopped when the returning lavage fluid was relatively clear (no optical density measurement capabilities were available at that time). The same procedure was repeated with the next bag of lavage solution.

Figure 1.

The Vest™ Airway Clearance System from Hill-Rom.

Figure 2.

Cannisters in sequence, of post lavage fluid showing decreasing amount of sediment.

After one lung lavage was complete both lungs were ventilated for about 20 minutes. After establishing stable ventilation and oxygenation the second lung was isolated. The second lung was now washed out as described previously, until the returning lavage fluid was essentially clear.

On completion of the lavage, the double lumen endotracheal tube was exchanged for a single lumen endotracheal tube before transporting the patient to the intensive care unit. The patients were extubated within 12–14 hours and were subsequently discharged from the hospital by the Pulmonary Medicine Service within 24 hours without any complications.

Results

WLL, although not curative, continues to be the current standard of care for PAP. Notably, patients who successfully underwent WLL have significant clinical, physiologic, and radiologic improvements in up to 84% of cases and improved survival rates compared with those who have never undergone WLL [Seymour and Presneill, 2002]. The procedure is well tolerated in a majority of cases but is not without its hazards. The overwhelming concern is hypoxemia during the lavage. Sepsis, hydrothorax, pneumonia and acute respiratory distress syndrome are some of the other complications following WLL [Huizar and Kavuru, 2009].

There are no evidence-based guidelines for initiating WLL. Patient factors such as the need for supplemental oxygen therapy (PaO₂ <60 mmHg on room air) shunt fraction >10–12%, and limitation of activities of daily living are the practical driving forces for initiating WLL [Huizar and Kavuru, 2009].

The lavage fluid used is normal saline in a vast majority of cases. Several reports describe addition of adjunctive compounds to lavage solutions (heparin and sodium bicarbonate) but there is no current evidence to recommend any specific additive at this time [Huizar and Kavuru, 2009].

Since the original description, numerous modifications of WLL have been reported. However, no single technique or lavage solution has emerged as the standard method to perform WLL. Case reports ranging from aborting the lavage prematurely to the extraordinary use of rescue extracorporeal membrane oxygenation (ECMO) and hyperbaric conditions for WLL have been described [Presneill et al. 2004; Cohen et al. 2011].

The procedure is now routinely and safely done with the use of general anesthesia [Michaud et al. 2009]. Intraoperative chest physiotherapy, changes in patient position from Trendelenberg to reverse Trendelenberg to turning the patient lateral to semiprone to better distribute and drain the lavage fluid are some of the variations in the procedure for WLL [Jansen et al. 1987].

The effective use of high-frequency chest wall oscillation (HFCWO) has been previously described in patients with neuromuscular and pulmonary disorders (e.g. cystic fibrosis, familial dysautonomia and amyotropic lateral sclerosis) who have an inherent inability to effectively clear their airway secretions leading to frequent pulmonary infections [Giarraffa et al. 2005; Lange et al. 2006]. HFCOW devices (such as the Vest™) inflate and deflate rhythmically to generate changes in airflow and shear forces within the airways simulating a cough and help clear secretions [Giarraffa et al. 2005]. To the best of the authors’ knowledge, this is first report of the novel intraoperative the use of a HFCWO device for enhancing airway clearance in PAP.

We were able to decrease the total operating room time by 86 minutes compared with the previous WLL in patient number 2 (when comparing total operating room time from previous anesthesia records). We agree that we do not have sufficient data (radiologic or optical density-based methods) to broadly extrapolate upon the efficacy of our method of performing WLL or the rates of needing repeat WLL in the future in this patient population. We however believe that using the chest physiotherapy system during WLL in selected patients can decrease total operating room time in the future.

Conclusions

The intraoperative use of the Vest™ Airway Clearance system can be a useful adjunct in completing large volume lung lavage in patients with clinically symptomatic PAP.