“PRE OPERATIVE ASSESSMENT TO
PREDICT POST-OPERATIVE
COMPLICATIONS IN PATIENTS
UNDERGOING LUNG RESECTION
SURGERY IN A TERTIARY CARE
CENTRE IN INDIA”
A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE
REQUIREMENT FOR THE MD BRANCH XVII (TUBERCULOSIS AND
RESPIRATORY MEDICINE) EXAMINATION OF THE TAMILNADU
CONTENTS
INTRODUCTION………..15
REVIEW OF LITERATURE……….17
AIMS& OBJECTIVES……….……….36
MATERIALS AND METHODS………37
RESULTS………...39
PRE VS POST OPERATIVE COMPARISONS………68
DISCUSSION……….80
LIMITATIONS………..86
CONCLUSIONS………87
CERTIFICATE
This is to certify that the dissertation titled “Pre-operativeassessment to predict post-operative complications in patients undergoing lung resection surgeries in a tertiary care centre in India” submitted towards fulfillment of the requirements of the Tamil Nadu Dr. M.G.R.MedicalUniversity for the MD TUBERCULOSIS AND RESPIRATORY MEDICINE examination to be conducted in May 2018, is the bonafide work of Dr.Sujith Thomas Chandy, postgraduate student in the Department of Pulmonary Medicine, Christian Medical College, Vellore.
GUIDE
Dr. Balamugesh T,
Professor and Head of the Department,
Department of Pulmonary Medicine,
CERTIFICATE
This is to certify that the dissertation titled “Pre-operativeassessment to predict post-operative complications in patients undergoing lung resection surgeries in a tertiary care centre in India” submitted towards fulfillment of the requirements of the Tamil Nadu Dr. M.G.R.MedicalUniversity for the MD TUBERCULOSIS AND RESPIRATORY MEDICINE examination to be conducted in May 2018, is the bonafide work of Dr.Sujith Thomas Chandy, postgraduate student in the Department of Pulmonary Medicine, Christian Medical College, Vellore.
Co-guide,
Dr.D.J Christopher,
Professor,
Department of Pulmonary Medicine,
CERTIFICATE
This is to certify that the dissertation titled “Pre-operativeassessment to predict post-operative complications in patients undergoing lung resection surgeries in a tertiary care centre in India” submitted towards fulfillment of the requirements of the Tamil Nadu Dr. M.G.R.MedicalUniversity for the MD TUBERCULOSIS AND RESPIRATORY MEDICINE examination to be conducted in May 2018, is the bonafide work of Dr.Sujith Thomas Chandy, postgraduate student in the Department of Pulmonary Medicine, Christian Medical College, Vellore.
Co-guide,
Dr.Prince James,
Professor,
Department of Pulmonary Medicine,
CERTIFICATE
This is to certify that the dissertation titled “Pre-operative assessmentto predict post-operative complications in patients undergoing lung resection surgeries in a tertiary care centre in India” submitted towards fulfillment of the requirements of the Tamil Nadu Dr. M.G.R.MedicalUniversity for the MD TUBERCULOSIS AND RESPIRATORY MEDICINE examination to be conducted in May 2018, is the bonafide work of Dr.Sujith Thomas Chandy, postgraduate student in the Department of Pulmonary Medicine, Christian Medical College, Vellore.
Co-guide,
Dr.Birla Roy Gnanamuthu,
Professor,
Department of Thoracic Surgery,
CERTIFICATE
This is to certify that the dissertation titled “Pre-operative assessmentto predict post-operative complications in patients undergoing lung resection surgeries in a tertiary care centre in India” submitted towards fulfillment of the requirements of the Tamil Nadu Dr. M.G.R.MedicalUniversity for the MD TUBERCULOSIS AND RESPIRATORY MEDICINE examination to be conducted in May 2018, is the bonafide work of Dr.Sujith Thomas Chandy, postgraduate student in the Department of Pulmonary Medicine, Christian Medical College, Vellore.
PRINCIPAL,
Dr. Anna Pulimood,
DECLARATION
This is to certify that the dissertation titled “Pre-operative assessment to predict post-operative complications in patients undergoing lung resection surgeries in a tertiary care centre in India” submitted towards fulfillment of the requirements of the Tamil Nadu Dr. M.G.R.MedicalUniversity for the MD TUBERCULOSIS AND RESPIRATORY MEDICINE examination to be conducted in May 2018.
Dr. Sujith Thomas Chandy,
Postgraduate Student (MD Tuberculosis and Respiratory Medicine),
Register Number:
Department of Pulmonary Medicine.
Christian Medical College,
ACKNOWLEDGEMENTS
I would like to express my sincere thanks and gratitude to my guide, Professor and Head of the Department of Pulmonary Medicine, Christian Medical College Vellore, Dr. Balamugesh T, for his well directed guidance, patience and constant encouragement during the write up and completion of my thesis.
I would also like to thank my co-guides, Dr. D.J Christopher, Professor in Pulmonary Medicine, Dr. Prince James, Professor in Pulmonary Medicine and Dr. Birla Roy Gnanamuthu, Professor in Thoracic surgery for their support and approachability in every step of this study. Also, I would like to acknowledge the help given by Dr. Korah T Kuruvila during the final phases of the study period.
I would like to express my sincere thanks to Dr. Visalakshi, Department of Biostatistics, for her quick responses in data formulations and analysis and guidance in making graphs and tables.
I would like to thank my colleagues in the Department of Pulmonary Medicine, my batch mate, seniors, juniors and consultants for helping me in every step of the study. I would like to thank my family and friends for helping me during the countless hours of work that has been put into this study.
I would also like to thank each and every patient who consented to be enrolled into this study and their relatives for their valuable time and willingness.
INTRODUCTION
Lung resection surgery is one of the major modalities of treatment of variety of lung diseases like lung cancer.The primary mode of treatment for stage I and stage II Non small cell carcinoma Lung is Resection(1). It is also a vital component in the multimodality approach to stage III A disease.
Less than 40% of Carcinoma Lung patients worldwide are candidates for curative resection. It is estimated that 20-30% of patients undergoing resection for Lung cancer have post-operative cardiopulmonary complications(2). Although there has been advancement in surgical technique and improved perioperative management, the rate of complications occurring continues to be significant.
Most commonly occurring complications post lung resection surgeries are pneumonia and atelectasis(2). There is a significant clinical and economic impact of post-operative pulmonary complications. There was an increased observed number of deaths, morbidity, length of stay and associated cost(2).
REVIEW OF LITERATURE
Common Indications for lung resection surgery: a. Malignancy
b. Bronchiectasis
c. Post Tuberculosis sequelae – Destroyed lung d. Aspergilloma
e. Lung Abscess f. Hydatid cyst g. Bronchogenic cyst
Surgical treatment of bronchiectasis was considered if symptoms persisted despite adequate medical treatment and if the extent of diseased lung was localized to justify surgery(22). Surgical resection for aspergilloma should be reserved for patients with severe hemoptysis who have adequate pulmonary function(23).
longer duration of high dependency unit stay, higher frequency of intensive therapy unit admissions and higher number of hospital deaths. Multivariate analysis of the data revealed that Age > 75, BMI >30, smoking history, COPD, ASA > 3 were all independent risk factors for the development of post-operative pulmonary complications(2).
In a four year study between 1994 to 1998 conducted in a tertiary centre in Japan, 89 patients with stage I to IIIA non-small cell carcinoma lung underwent lung resection surgery. They were evaluated for the feasibility of making pre-operative prediction of pulmonary complications. All patients had a predicted FVC > 800ml or FEV-1 > 600ml.
There were 62 men and 27 women in the defined study population. Twenty four patients had squamous cell carcinoma, sixty had adenocarcinoma, three had large cell carcinoma, one had adenosquamous carcinoma and one had large cell neuroendocrine carcinoma. Pulmonary function tests revealed an obstructive defect in eight (9.0%), a restrictive defect in five (5.6%) and a combined obstructive with restrictive defect in 3(3.4%).
Non pulmonary complications included bradycardia, atrial fibrillation, premature ventricular contractions, liver dysfunction, gastric ulcer defined by endoscopy, post-operative depression, colitis and wound infection, all of which required treatment.
All patients were extubated on the day of surgery and there were no deaths with re-surgery being required in just one patient following empyema thoracis. There were no patients who required tracheostomy or mechanical ventilation.
Results obtained from this study was as follows –
1. 37 patients developed post-operative complications out of which 20 patients developed pulmonary complications.
2. Multivariate analysis showed three factors (serum LDH levels of > or =230 U/l, RV/TLC > or =30%, and PaO(2) < 80mmhg) were significantly associated with pulmonary complications in patients undergoing a lobectomy for NSCLC(5).
3. Univariate analysis which included age, sex, smoking history, Serum albumin and serum protein, %FEV1, FEV1%, RV/TLC, hypercapnia, operative procedure, operated site, the existence of adhesions at operation, the pathological T and N stage, and the histological type were not predictive of pulmonary complications.
perioperativeand post-operative complications and also long term disability. Further perioperative risk secondary to atherosclerotic cardiovascular disease can also be attributed to cigarette smoking in these patients. Oncological intervention is possible even though it could be considered to be a suboptimal treatment strategy. Therefore whenever a patient is planned for a curative intent surgical resection, perioperative risk from baseline cardiopulmonary disease and also the long term risk of pulmonary disability should be balanced with the possibility of reduced survival with oncological intervention(4).
Latest guidelines from American college of chest physicians states that patients with predicted post-operative FEV1 and DLCO more than 60%, have low risk for postoperative complications even with pneumonectomy surgery. While patients with VO2 max less than 10ml/kg/min or less than 35% of predicted have high risk of post-operative complications and even lobectomy or segmentectomy should be avoided(6).
patients were above the age of 75 years. For patients more than 70 years of age, mortality rates were estimated to be the following:-
1. For lobectomy – 4% to 7%
2. For pneumonectomy – around 14%
These were higher than the mortality rates for patients less than 70 years of age:
1. For lobectomy – 1% to 4% 2. For pneumonectomy – 5% to 9%
This significant difference is more a function of underlying co-morbidities than age alone. Limited information suggests that carefully selected patients who are 80 years of age can tolerate lung cancer resection. A retrospective analysis(7) from Johns Hopkins Hospital reported that 17% of the octogenarians in whom lung cancer was diagnosed between 1980 and 2002 underwent surgical resection. In this series of 68 patients in their 80s who were undergoing curative-intent surgery for NSCLC, the 30-day mortality rate was 8.8%(7).
PULMONARY FUNCTION TESTS:
pneumonectomyachieved a similar mortality rate. FEV-1 > 80% of predicted has been considered acceptable for patients planned for pneumonectomy without undergoing further evaluation.
Interest in Diffusion capacity of the lung for carbon monoxide (DLCO) as a useful marker for perioperative risk was initiated by Ferguson et al(8) who related DLCO with preoperative DLCO with postoperative morbidity and mortality in 237 patients. Selection for lung resection surgery was based on clinical presentation and spirometry but not DLCO which was also measured. DLCO < 60% predicted was found to have a higher correlation with postoperative mortality than FEV1 percentage predicted or any other parameter. Also the risk of pulmonary complications increased 2-3 fold with DLCO < 80%.
The American College Of Chest Physicians (ACCP) has a set of recommendations, latest updated in the year 2013 for guidelines for the physiological evaluation of patients with Lung Cancer being considered for lung resection surgeries. These are the following guidelines(6)
2. It is recommended that those patients with lung cancer should not be denied lung resection surgery on the grounds of age alone and that they fully be evaluated regardless of age(6).
3. It is recommended that lung cancer patients with who have major factors which can predispose to increased perioperative cardiovascular risk have a pre operative cardiovascular assessment with further management as per existing cardiology guidelines for non cardiac surgery(6)
4. Spirometry is recommended for patients being considered for lung resection surgeries.
a) If FEV-1 > 80% predicted or 2 L and there is no evidence of undue dyspnea on exertion or interstitial lung disease, there is no need for further physiological evaluation and the patient is suitable for resection surgeries including pneumonectomy (6).
b) If FEV-1 > 1.5 L and there is no evidence of undue dyspnea on exertion or interstitial lung disease, there is no need for further physiological evaluation and the patient is suitable to under lobectomy (6).
5. Even if FEV-1 is adequate, in those patients having undue dyspnea on exertion or interstitial lung disease, measurement of DLCO is recommended (6).
time of lung resection surgery (6). The methods used for this includes the following:
a) Perfusion scans like the radionuclide scan which is the preferred method for pneumonectomy
b) Ventilation scans c) Quantitative CT scan
d) Anatomical estimation method – preferred for lobectomy.
It is based on counting the number of segments to be removed. The following formula is used for this method.
PPO FEV-1 = pre operative FEV-1 x (1 – y/z)
Pre-operative FEV-1 is the best measured post bronchodilator value
y – number of unobstructed lung segments or functional segments to be removed z – total number of functional segments.
Percentage ppo FEV-1 can be calculated using standard equations. The %ppo FEV01 has strong correlation with the actual post-operative FEV-1.
7. It is recommended that patients who have FEV-1 less than 40% ppo and DLCO less than 40% ppo, undergo exercise testing as these patients are at increased risk of perioperative death and cardiopulmonary complications (5).
CARDIOPULMONARY EXERCISE TESTING:
- Recording the exercise ECG - Heart rate response to exercise - Minute ventilation
- Oxygen uptake per minute
- Maximum oxygen consumption (VO2 max)
The risk of perioperative complications occurring has generally been observed to be higher in patients who have a lower VO2 max. Patients having a VO2 max of 15-20 ml/kg can undergo curative intent lung resection surgery with a relatively low mortality rate.
WALK TESTS:
When Cardiopulmonary exercise testing is unavailable, walking tests can be used as exercise testing. Stair climbing has historically been used as a surrogate for CPET. Patients who could climb 3 flights of stairs were considered suitable candidates for lobectomy. Pneumonectomy candidates were expected to climb 5 flights of stairs. The number of flights was found to correlate with lung function:
- 3 flights of stairs = FEV-1 of 1.7 L - 5 flights of stairs = FEV-1 of 2 L
Shuttle walk and 6-minute walk tests can be used to identify patients who desaturate during exercise. More than 4% desaturation has been reported earlier to indicate an increased risk of perioperative complications(6).
cardiopulmonary complications and perioperative death with standard lung resection surgery. Therefore it is recommended that these patients be counseled about non operative treatment options for lung cancer and non standardsurgeries (6).
9. A Vo2 max of less than 10 ml/kg/min, in those patients with Carcinoma Lung being considered for surgery indicates an increased risk of cardiopulmonary complications and perioperative death with standard lung resection surgery. Non standard surgery and non operative treatment options for Lung cancer need to be discussed with these patients (6).
10. Those patients who have a Vo2 max less than 15 ml/kg/min and both DLCO and FEV-1 of less than 40% of ppo(predicted post-operative) are at increased risk of cardiopulmonary complications and perioperative death with stand lung resection surgery. These patients also need to be counseled on non operativetreatment options and non standard surgery for lung cancer(6). 11. Patients who walk less than 25 shuttles on two shuttle walks or less than one
flight of stairs are at increased risk of cardiopulmonary complications and perioperative death after lung resection surgery. Counseling on non operative treatment options and non standard surgery needs to be done with these patients with lung cancer(5).
13. A saturation of less than 90% in patients with lung cancer who are planned for surgery, indicates an increased risk for perioperative complications with standard lung resection surgery. Hence it is recommended that further physiological testing be done in these patients(5).
European respiratory society guidelines published in 2009 advise that patients with FEV1 and DLCO more than 80% of predicted have very low risk of postoperative complications , even with pneumonectomy surgery, while patients with VO2 max less than 10ml/kg/min or less than 35% of predicted have high risk of postoperative complications and even lobectomy or segmentectomy should be avoided(9).
Predicted post-operative(ppo) forced expiratory volume in 1 second (ppo FEV-1) plays a pivotal role in choosing further investigations and even excluding patients from surgery without proceeding with more tests. Multiple case series have demonstrated that perioperative risks increase substantially when ppo FEV-1 is less than 40% of the predicted value with mortality rates ranging from 16-50%.
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PREDICTED POST-OPERATIVE LUNG FUNCTION
The extent of lung resection has an impact on operative mortality and can determine post-operative lung function. Also it may influence overall survival and cancer specific survival(11). It was a retrospective study where the relationship of ppo FEV-1 and ppo DLCO to long term survival was assessed using Cox regression analysis. Of the 854 patients, 55% were men and at the time of analysis 70% had died. It was found that pre-operative lung function was marginally associated with mortality, with a DLCO having 10% point decrease and a p value of 0.056. In contrast, post-operative lung function, was strongly associated with mortality with ppo DLCO having a p value of 0.024 and a confidence interval of 1.01 – 1.12 and ppo FEV-1 having a p value of 0.031 and a confidence interval of 1.01 -1.12(9).
The Thoracic Revised Cardiac Index (ThRCRI):
Cardiac risk stratification is an important tool that provides both the surgeon and the patient information regarding “Risk to benefit” ratio before planning a lung resection surgery. The RCRI – Revised Cardiac Risk Index was initially developed as a risk stratifying tool for patients who were to undergo non cardiac surgeries(14). Its validation included a relatively small number of thoracic surgery patients and due to its broad acceptance as a predictor of cardiovascular risk, very few studies have looked into its predictive abilities in patients who were to undergo thoracic surgeries. With a revision of the RCRI, the ThRCRI (Thoracic Revised Cardiac Risk Index) has emerged as an essential tool to predict post-operative cardiovascular complications in patients undergoing lung surgeries(10).
The ThRCRI differentiates patients into Class A or B, that is patients who can proceed to lung resection from patients who need to receive further cardiac evaluation, i.e., Class C or D which carries a 3 fold increase risk of cardiac complication. It utilizes data that is easily available from the outpatient pre-operative setting, hence simplifying the risk assessment process. The ThRCRI can be useful as a first line screening instrument utilized by clinicians for patients planned for lung resection surgeries before they perform pulmonary function tests.
The study population used in this study included patients above 18 years of age undergoing lobectomy or bilobectomy or pneumonectomy or Open or Video Assisted Thoracic Surgery (VATS). Both malignant and non malignant cases requiring lung resection were included and those who needed emergency surgeries were excluded.
DEFINITIONS OF OUTCOMES
POST-OPERATIVE FEVER
Adult post-operative Fever is defined as an elevation of body temperature of more than 38.3 degrees centigrade (100.4 degrees Farenheit) (11). The specific influential pyrogenic cytokines are the Interleukins – IL-1, IL-6, Tumor necrosis factor – TNF and Interferron gamma. These cytokines specially affect post-operative temperature regulation(11).
BRONCHOPLEURAL FISTULA/AIR LEAK
It is a communication between the pleural space and the bronchial tree. The most common cause for BPF is pulmonary resection(16) and the most common complication occurring post lung resection surgeries is BPF(16). The incidence following lung resection surgeries have been reported to be 1.5 to 28%(16). This variability depends on etiology, the surgeon’s experience and surgical technique. Compared to malignancy the incidence is lower for benign conditions.
Air leak can occur any time post-operatively but most often occurs within 8-12 days following surgery(16).
POST-OPERATIVE ATELECTASIS:
increased bronchial secretions. Besides cough, patients may have documented periods of hypoxemia which usually occurs from the second post-operative night(17). Radiology can show areas of collapse with compensatory hyperinflation of the opposite side. Patients are advised incentive spirometry and gentle chest physiotherapy at least every four to six hours.
AIMS& OBJECTIVES
A) Primary objective - To show that pre-operative tests, mainly FEV-1 can predict post-operative complications like atelectasis, pneumonia, bronchopleural fistula, increased duration of post-operative hospital stay, duration of admission in HDU and mortality rates.
B) To show that other pulmonary function tests like FVC, 6min walk test and also Cardiopulmonary testing like V02max and VE/VCO2 can predict these outcomes.
C) To obtain a clinical profile of patients undergoing lung resection surgery.
MATERIALS AND METHODS
Sample size calculation:
The required sample size to show that pre-operative tests like FEV1 is able to predict post-operative complications was found to be 100 subjects with 80% power, 5% level of significance and an anticipated odds of 2.5 with a prevalence of post-operative complications to be 20% (Ref: Am J RespirCrit Care Med. 1995 May;151(5):1472-80).
Formula:
Ref: Hsieh, F.Y. (1989). Sample size tables for logistic regression. Statistics in
Medicine 8: 795-802.
Anticipated odds ratio 2 2.5
Power (1- beta) % 80 80
Alpha error (%) 5 5
1 or 2 Sided 2 2
All patients with any indication for lung resection surgery were included in the study. The exclusion criteria were the following:
1. Children below the age of 18 years. 2. Pregnancy
Written consent was taken in the language they understand and information sheet was provided. All patients underwent a quality of life questionnaire, the St George Respiratory Questionnaire prior to surgery. Spirometry, Lung volumes and DLCO were done during outpatient visits and cardiopulmonary exercise testing and Six minute walk test on the day of admission in Thoracic surgery ward, prior to surgery.
Complications occurring intra operatively were informed and patients were monitored during perioperative and post-operative period in Semi ICU followed by the general ward.
RESULTS
The baseline characteristics of the 100 patients (males = 55; females = 45) that were enrolled in this study after inclusion and exclusion criteria are given in the following Table 1.1 and Table 1.2.
Co-morbidities in 100 patients
[image:40.595.67.438.264.628.2]The sample size which was calculated was 99, however 100 pre-operative patients were recruited. Males compromised 55% of patients. Twenty two patients had Type 2 Diabetes Mellitus and 13 patients had Systemic Hypertension and all were Primary or Essential Hypertension with no secondary cause identified at the time of surgery.
Table 1.1
Comorbidity Present Absent
Diabetes Mellitus II 22 78
Systemic Hypertension
13 87
Coronary Artery Disease
3 97
Bronchial Asthma 14 86
COPD 1 99
Past history of Tuberculosis
38 62
Smoking 16 84
Alcohol use 16 84
Inhaler use 23 77
Three patients were known to have Coronary artery disease and these patients were counseled pre-operatively regarding the increased risk of cardio-pulmonary complications and perioperative death.
Fourteen patients were known cases of Bronchial Asthma and were all on inhalers. However the total number of patients on inhalers were 23, with the other indications for inhaler use being bronchiectasis, COPD and some patients who were diagnosed withaspergilloma and referred for surgical treatment had been commenced on inhalers. Thirty eight patients had been previously diagnosed and treated for tuberculosis and a significant number of subjects who underwent lung resection surgery did so for post tubercular sequelae including bronchiectasis, destroyed lung and aspergilloma.
Baseline characteristics of pre operative patients:
[image:42.595.67.524.142.409.2]Mean age of the 100 patients enrolled in the study was 41.67 +/- 12.124 years. Diabetic patients which comprised 22% of total number of cases had a mean HBA1C of 7.93 +/- 2.291.
Table 1.2
Parameter
Mean
Standard deviation(+/-)
Age (Years)
41.67
12.124
Hb (g/dl)
12.67
1.840
Platelets (per mm
3)248130
109443.003
PT (sec)
10.61
0.684
GRBS (mg/dl)
122.83
48.04
INDICATION FOR SURGERY:
The most common indication for surgery was neoplasm, which included adenocarcinoma and squamous cell carcinomas of the lung, carcinoid tumors, both typical and atypical andmetastasis from another primary.
[image:43.595.69.460.313.767.2]Other common indications were bronchiectasis which was mostly related to post tubercular sequelae, aspergilloma and hydatid cyst. All indications are summarized in Table 2.1.
Indication for surgery
Malignancy = 37Bronchiectasis = 21
Destroyed Lung = 4
Aspergilloma = 19
Lung Abscess = 1
Hydatid cyst = 8
[image:43.595.67.292.315.512.2]Misc = 10
Table 2.1
Indication for surgery
Frequency
Neoplasm 37
Bronchiectasis 21 Destroyed lung 4
Aspergilloma 19
Lung abscess 1
Hydatid cyst 8
Misc 10
Type of neoplasm
Table 2.2
Type of neoplasm Frequency
Adenocarcinoma 9
Carcinoid 12
Squamous cell carcinoma 4
Metastasis 10
Myofibroblastoma Leiomyoma
1 1
Total 37
Non malignancy 67
Total 100
Adenocarcinoma = 9
Carcinoid = 12 Squamous
cell = 4 Metastasis = 10
Myofibroblastoma = 1
Leiomyoma = 1
Surgery planned:
The most common surgery planned by the thoracic surgeon was lobectomy. Seventy fivepercent cases were planned for lobectomy. The other planned surgeries include pneumonectomy, metastatectomy, segmentectomy or wedge resection.
[image:45.595.66.340.243.507.2]Surgery planned
Table 2.3
Surgery planned
Frequency
Lobectomy 75
Pneumonectomy 6
Wedge resection 1
Metastatectomy 7
Segmentectomy 3
Miscellaneous 8
Surgery done:
The surgery planned need not necessarily be the surgery that is performed finally. On table decisions can change based on intra operative findings. Finally out of 75 lobectomies planned only 69 pure lobectomies performed. Some were converted into combination surgeries, namely, lobectomy with metastatectomy, lobectomy with segmentectomy and lobectomy with bronchoplasty.
[image:46.595.66.353.321.560.2]Surgery done
Table 2.4
Surgery done
Frequency
Lobectomy 69
Pneumonectomy 6
Wedge resection 7
Segmentectomy 4
Lobectomy &Segmentectomy 5
Miscellaneous 9
Graph 1.0
50 54 58 62 66 70 74 78
Lobectomy performed
Lobectomy planned
69 75
Baseline pre operative parameters:
Table 3.1
PARAMETER MEAN
Standard Deviation(+/-)
FVC (litres) 2.82 0.743
FVC% 85.23 16.834
FEV-1(litres) 2.28 0.629
FEV-1% 81.94 17.384
FEV-1/FVC 80.78 7.761
PEFR (litres) 6.62 2.009
TLC (litres) 4.85 6.168
TLC% 88.33 20.93
RV (litres) 1.33 0.507
RV% 89.89 32.246
6 MIN W.D (metres) 425.91 73.053
6 MIN W.D% 69.68 13.763
DSP m% 417.04 73.806
VO2 PEAK 1395.69 342.249
VO2 PEAK% 69.52 12.845
O2 PULSE PER H.B 8.55 2.726
A.T 1147.24 331.869
A.T% 58.69 17.05
VE/VCO2 33.69 4.807
DLCO (litres) 8.05 2.223
DLCO% 94.06 26.194
DLCO/VA 2.29 0.378
DLCO/VA% 151.86 29.304
SGRQ-1 28.92 24.542
SGRQ-2 25.24 29.484
SGRQ-3 20.25 19.244
SGRQ-TOTAL 23.12 21.248
The most important parameter to be considered before lung resection is FEV-1. The mean FEV-1 was2.28 litres with a standard deviation of +/- 0.629. DLCO corrected for Hemoglobin is the other important pre-operative parameter for assessment of lung resection surgeries. In our study,mean DLCO was8.05 litres with a standard deviation of +/- 2.223. FEV-1 more than 80% was found in 54 patients (54%).
DURATION OF AIR LEAK:
Recent literature defines Prolonged Air Leak (PAL) as air leak that lasts for more than 5 days(16). But various centers follow different definitions and the Thoracic surgery department in our institution considers more than 7 days as prolonged air leak. In our cohort of patients, the mean duration of air leak was 4.83 days with a standard deviation of +/- 2.705 with a maximum duration of air leak of 12 days. Only 5 patients had prolonged air leak of more than 7 days which indicates good surgical outcome. In graph 1.01 we compare the duration of prolonged air leak for the 5 patients with the duration of chest tube in-situ and day of discharge.
Graph 1.01 0 2 4 6 8 10 12 14 patient 1 patient 2 patient 3 patient 4 patient 5
duration of air leak
duration of chest tube
DURATION OF CHEST TUBE INSITU:
The mean duration of chest tube in-situ post-operatively was 5.18 days with a standard deviation of +/- 2.812 days. Factors that influenced total duration of intercostal drainage were:
- Daily drain measurements - Presence of air leak
- Temperature
- Hemodynamic stability - Chest x ray findings
Intercostal drainage acts as a safety valve and premature removal can lead to re-accumulation of fluid, fever and non expansion of lung and eventually to re-insertion of chest tube.
DURATION OF ICU STAY:
Most patients after lung resection surgery are kept in ICU for a period of 24 to 48 hours post-operatively.The mean duration of ICU stay was 44.40 hours with a standard deviation of 31.101 with a minimum of 24 hours and maximum of 240 hours.
Duration of ICUstay, chest tube insitu and air leak
All patients were extubated on table. As per protocol in our institution, the average duration of ICU stay is less than 48 hours.
FEV-1/FVC ratio was the only variable which was found to be significantly associated with duration of ICU stay. The p value was 0.024 and the correlation coefficient was -0.226, implying that lower the FEV-1/FVC ratio, longer the duration of ICU stay.
OUTCOMES
The primary outcome measures that were looked peri and post operatively were:
1. Post-operative fever – documented temperature of more than 100.4 degrees Fahrenheit.
2. Post-operative atelectasis – clinical and radiologically.
3. Air leak – presence of air leak as seen in the intercostal drainage system.
[image:51.595.67.521.143.255.2]4. Miscellaneous post-operative complications – non cardiopulmonary complications.
Table 3.2
Post-operative duration
Mean
Standard
deviation
Duration of ICU stay (hours) 44.4 31.101Duration of chest tube (days) 5.18 2.812
POST-OPERATIVE FEVER
Totally 7 patients (7%) had developed post-operative fever.
Spirometry parameters that had statistically significant p value of < 0.05 in relation to post-operative fever were:
a) Forced vital Capacity – FVC b) Total Lung Capacity – TLC
c) Peak Expiratory Flow rate – PEFR d) Residual Volume – RV
Table 4.1
PRE OP INVESTIGATION Post op fever present Post op fever absent p-value
Mean ± S.D Mean ± S.D
FVC (litres) 3.38 ± 0.54 2.78 ± 0.74 0.026
FVC % 95.61 ± 15.41 84.44 ± 16.75 0.089 FEV-1(litres) 2.58 ± 0.46 2.26 ± 0.63 0.131 FEV-1% 88.04 ± 17.66 81.47 ± 17.37 0.224 FEV-1/FVC 76.36 ± 6.08 81.12 ± 7.79 0.089 PPO FEV-1(litres) 2.10 ± 0.42 1.86 ± 0.63 0.231
PEFR(litres) 8.08 ± 1.17 6.51 ± 2.02 0.027
TLC(litres) 5.08 ± 0.87 4.83 ± 6.44 0.017
TLC% 94.48 ± 10.99 87.77 ± 21.57 0.127
RV(litres) 1.72 ± 0.61 1.30 ± 0.48 0.030
RV% 104.11 ± 31.33 88.58 ± 32.21 0.136 6MIN W.D(metres) 446.14 ± 75.14 424.14 ± 73.08 0.408 6MIN W.D% 77.77 ± 15.02 68.96 ± 13.51 0.068 DSP (m%) 432.20 ± 74.80 415.37 ± 73.95 0.426 VO2peak 1402.80 ± 423.12 1395.19 ± 339.47 0.877 VO2peak% 67.20 ± 14.07 69.68 ± 12.84 0.413 VO2peak per kg 22.50 ± 2.83 23.44 ± 5.16 0.816 O2 pulse per HB 7.26 ± 0.30 8.61 ± 2.77 0.284 AT 1265.40 ± 424.36 1138.80 ± 326.48 0.672
AT% 60.60 ± 15.82 58.55 ± 17.23 0.829
Ve/Vco2 33.98 ± 7.85 33.67 ± 4.60 0.926
DLCO(litres) 9.22 ± 1.66 7.92 ± 2.24 0.096
DLCO% 113.18 ± 22.89 91.91 ± 25.82 0.037
DLCO/VA 2.18 ± 0.25 2.31 ± 0.38 0.352
DLCO/VA% 172.42 ± 32.92 149.54 ± 28.22 0.079 SGRQ-1 27.77 ± 14.10 29.01 ± 25.20 0.823 SGRQ-2 18.00 ± 22.23 25.78 ± 29.98 0.829 SGRQ-3 14.87 ± 12.14 20.66 ± 19.66 0.771 SGRQ-Total 17.64 ± 14.00 23.54 ± 21.69 0.792
FVC – Forced vital capacity; FEV-1 – Forced expiratory volume in the first second; PEFR – peak expiratory flow rate; TLC – Total lung capacity; RV – Residual volume; 6 MIN W.D – six minute walk distance; DSP – Distance saturation product; VO2 peak – maximum rate of oxygen consumption during incremental exercise; O2 pulse per H.B – Oxygen pulse per heart beat; A.T – Anaerobic Threshold; VE/VCO2 – Ventilatory equivalent ratio for Carbon dioxide; DLCO – Diffusion capacity of lung for carbon monoxide; DLCO/VA – Diffusion capacity of lung for carbon monoxide per alveolar volume ventilated; SGRQ – St George Respiratory Questionnaire.
Those patients who have higher volumes of Forced vital capacity, Total lung capacity, Peak expiratory flow rate and Residual volume are more likely to have post-operative fever more than 100.4 degree Fahrenheit.
Post-operative Atelectasis
Totally 7 out of 100 patients developed post-operative atelectasis.
The pulmonary function tests that had significant p values of < 0.05 for predicting post-operative atelectasis were:
a) Total lung capacity % - TLC% b) Residual Volume – RV
c) Residual Volume % - RV%
Table 4.2 PRE OP
INVESTIGATION
YES Mean ± S.D
NO Mean ± S.D
p-value
2.88 ± 0.96 95.32 ± 20.96
2.46 ± 0.88 95.82 ± 22.75
81.11 ± 6.87 2.24 ± 0.88 7.21 ± 2.88 5.01 ± 1.06 FVC FVC % FEV-1 FEV-1% FEV-1/FVC PPO FEV-1 PEFR TLC
2.82 ± 0.73 84.46 ± 16.36
2.27 ± 0.61 80.88 ± 16.59 80.76 ± 7.85
1.85 ± 0.59 6.58 ± 1.94 6.20 ± 1.73
0.848 0.238 0.495 0.076 0.951 0.185 0.571 0.820
TLC% 102.96 ± 16.94 87.40 ± 20.90 0.027
RV 1.87 ± 0.50 1.30 ± 0.49 0.017
RV% 122.06 ± 37.23 87.83 ± 31.04 0.020
6MIN W.D 428.60 ± 146.98 425.74 ± 67.81 0.777
6MIN W.D% 76.50 ± 26.63 69.26 ± 12.75 0.381
DSP 418.78 ± 143.56 416.94 ± 69.03 0.806
VO2peak 1452.25 ± 199.02 1392.51 ± 349.19 0.577
VO2peak% 71.86 ± 13.57 69.38 ± 12.89 0.593
VO2peak per kg 22.55 ± 4.33 23.42 ± 5.09 0.707
O2 pulse per HB AT AT% Ve/Vco2 DLCO DLCO% DLCO/VA DLCO/VA% SGRQ-1 SGRQ-2 SGRQ-3 SGRQ-Total
9.06 ± 1.69 1268.75 ± 98.08
63.50 ± 11.90 33.72 ± 1.88
9.42 ± 1.84 106.35 ± 14.85
2.49 ± 0.56 176.32 ± 48.78
25.70 ± 24.99 10.65 ± 18.69 10.45 ± 12.05 13.06 ± 15.75
8.53 ± 2.77 1140 ± 339.30
58.42 ± 17.32 33.69 ± 4.92
7.96 ± 2.22 93.31 ± 26.62
2.28 ± 0.36 150.36 ± 27.58
29.16 ± 24.62 26.34 ± 29.92 20.99 ± 19.52 23.88 ± 21.47
0.420 0.296 0.285 0.829 0.196 0.222 0.644 0.349 0.690 0.125 0.161 0.146
FVC – Forced vital capacity; FEV-1 – Forced expiratory volume in the first second; PEFR – peak Expiratory flow rate; TLC – Total lung capacity; RV – Residual volume; 6 MIN W.D – six minute walkdistance; DSP – Distance saturation product; VO2 peak – maximum rate of oxygen consumptionduring incremental exercise; O2 pulse per H.B – Oxygen pulse per heart beat; A.T– AnaerobicThreshold; VE/VCO2 – Ventilatory equivalent ratio for Carbon dioxide; DLCO – Diffusion capacityof lung for carbon monoxide; DLCO/VA – Diffusion capacity of lung for carbon monoxide peralveolar volume ventilated; SGRQ – St George Respiratory Questionnaire.
AIR LEAK
A total of 23 out of 100 patients developed air leak.
None of the pulmonary function tests could predict development of air leak. None of the spirometrical or cardiopulmonary exercise testing parameters showed significant p values.
Table 4.3 PRE OP
INVESTIGATION YES NO p-value
Mean ± S.D Mean ± S.D
FVC (litres) 2.79 ± 0.75 2.83 ± 0.74 0.737
FVC % 86.81 ± 15.45 84.75 ± 17.29 0.753
FEV-1(litres) 2.27 ± 0.61 2.29 ± 0.63 0.885
FEV-1% 81.58 ± 17.26 82.05 ± 17.53 0.829
FEV-1/FVC 80.57 ± 8.18 80.85 ± 7.68 0.756
PPO FEV-1(litres) 1.94 ± 0.51 1.86 ± 0.65 0.522
PEFR(litres) 6.47 ± 1.63 6.67 ± 2.11 0.709
TLC(litres) 6.62 ± 11.97 4.23 ± 0.95 0.410
TLC% 93.30 ± 34.77 86.65 ± 13.45 0.992
RV(litres) 1.35 ± 0.62 1.32 ± 0.46 0.629
RV% 94.82 ± 40.61 88.22 ± 29.08 0.582
6MIN W.D(metres) 420.27 ± 60.68 427.82 ± 77.12 0.532
6MIN W.D% 66.17 ± 9.41 70.81 ± 14.78 0.200
DSP(m%) 408.82 ± 65.92 419.82 ± 76.56 0.423
VO2peak 1295.89 ± 366.69 1427.21 ± 331.28 0.197
VO2peak% 67.18 ± 14.39 70.25 ± 12.36 0.205
VO2peak per kg 23.00 ± 5.33 23.50 ± 4.97 0.687
O2 pulse per HB 8.18 ± 2.50 8.66 ± 2.80 0.614
AT 1009.72 ± 390.76 1190.67 ± 301.97 0.117
AT% 54.66 ± 14.76 59.96 ± 17.64 0.312
Ve/Vco2 33.67 ± 5.51 33.70 ± 4.61 0.543
DLCO(litres) 7.79 ± 1.95 8.12 ± 2.30 0.635
DLCO% 85.78 ± 21.99 96.37 ± 26.97 0.160
DLCO/VA 2.27 ± 0.35 2.30 ± 0.38 0.866
DLCO/VA% 143.60 ± 19.18 154.16 ± 31.30 0.292
SGRQ-1 33.38 ± 27.17 27.59 ± 23.72 0.443
SGRQ-2 25.91 ± 30.05 25.04 ± 29.50 0.764
SGRQ-3 21.30 ± 21.43 19.94 ± 18.68 0.847
SGRQ-Total 24.55 ± 22.41 22.69 ± 21.02 0.724
MISCELLANEOUS POST-OPERATIVE COMPLICATIONS
Totally 11 out of 100 patients developed miscellaneous post-operative complications.
Some of the non cardiopulmonary complications that occurred post-operatively were:
1. Post-operative urinary retention 2. Post-operative psychosis 3. Wound infection – class 2 4. Lymph leak
Table 4.4
PRE OP INVESTIGATION YES Mean ± S.D
NO Mean ± S.D
p-value
2.65 ± 0.61 81.14 ± 17.43
2.12 ± 0.52 77.79 ± 18.37
79.96 ± 8.43 1.75 ± 0.43 5.76 ± 1.66 4.32 ± 0.91 FVC (litres) FVC % FEV-1(litres) FEV-1% FEV-1/FVC PPO FEV-1(litres) PEFR(litres) TLC(litres)
2.85 ± 0.76 85.77 ± 16.92
2.31 ± 0.64 82.60 ± 17.28 80.98 ± 7.65
1.90 ± 0.64 6.76 ± 2.04 4.94 ± 6.51
0.456 0.239 0.426 0.378 0.653 0.591 0.092 0.703
TLC% 89.00 ± 20.91 88.62 ± 21.24 0.556
RV(litres) 1.38 ± 0.61 1.34 ± 0.49 0.721
RV% 91.53 ± 45.90 90.61 ± 30.01 0.807
6MIN W.D(metres) 454.50 ± 60.71 422.17 ± 74.45 0.178
6MIN W.D% 72.17 ± 8.37 69.34 ± 14.36 0.322
DSP(m%) 438.65 ± 72.80 414.04 ± 63.36 0.253
VO2peak 1301.25 ± 165.54 1404.14 ± 358.64 0.626
VO2peak% 63.00 ± 10.67 70.41 ± 12.99 0.174
VO2peak per kg 23.58 ± 4.97 23.33 ± 5.11 0.924
O2 pulse per HB AT AT% Ve/Vco2 DLCO(litres) DLCO% DLCO/VA DLCO/VA% SGRQ-1 SGRQ-2 SGRQ-3 SGRQ-Total
8.37 ± 1.36 1093.88 ± 169.95
53.12 ± 10.03 36.40 ± 7.68
8.78 ± 2.32 106.68 ± 20.93
2.29 ± 0.56 160.35 ± 33.51
34.11 ± 20.10 26.91 ± 26.33 22.38 ± 16.11 25.56 ± 16.71
8.55 ± 2.86 1150.14 ± 347.94
59.42 ± 17.76 33.38 ± 4.35
7.97 ± 2.25 92.47 ± 26.74
2.28 ± 0.36 150.67 ± 29.44
28.14 ± 25.03 24.70 ± 29.63 19.74 ± 19.31 22.56 ± 21.44
0.824 0.728 0.360 0.403 0.360 0.161 0.814 0.407 0.276 0.589 0.443 0.434
FVC – Forced vital capacity; FEV-1 – Forced expiratory volume in the first second; PEFR – peak expiratory flow rate; TLC – Total lung capacity; RV – Residual volume; 6 MIN W.D – six minute walk distance; DSP – Distance saturation product;
VO2 peak – maximum rate of oxygen consumption during incremental exercise; O2 pulse per H.B – Oxygen pulse per heart beat; A.T– Anaerobic Threshold; VE/VCO2 – Ventilatory equivalent ratio for Carbon dioxide; DLCO – Diffusion capacity of lung for carbon monoxide; DLCO/VA – Diffusion capacity of lung for carbon monoxide per alveolar volume ventilated; SGRQ – St George Respiratory Questionnaire.
The primary objective of this study was to use FEV-1 to predict post lung resection surgery complications. As seen from the above tables, FEV-1 could not predict any of the above mentioned complications. The other lung function parameters like FVC, TLC, TLC%, RV, RV% and DLCO% were also not good predictors of these complications.
FEV-1 > 80% was found in 54 patients.
PPO FEV-1
The predicted change post-operative FEV-1(ppo FEV-1) was compared with FEV-1 post-op to assess whether it could accurately predict FEV-1 volumes once lung resection is done, using the standard anatomical formula mentioned above. It was also compared with FEV-1% post-op. Following are the comparisons made for patients who had both pre-operative and post-operative tests:
ACTUAL POST-OP FEV-1 VS PPO FEV-1
Graph 2.0
Table 5.1
Correlations with PPO FEV-1
PPO FEV1 FEV-1 post op Correlation Coefficient .838
Sig. (2-tailed) .000
N 48
FEV-1 % post op Correlation Coefficient .712 Sig. (2-tailed) .000
N 48
Graph 2.1
– Pre-op FEV-1 vs Predicted FEV-1 and actual FEV-1
The mean difference between predicted post-op FEV-1 and actual post-operative FEV-1 is -76 ml to + 76 ml.
2.4063
actual post o pFEV-1 = 2.0018
PPO FEV-1 = 1.9225
0 0.5 1 1.5 2 2.5 3
FEV1 pre op FEV1 post op
M
e
an
PPO VO2 max VS ACTUAL POST OP VO2 MAX
Graph 2.2
Range of predicted post-operative VO2 max from the actual post-operative VO2 max is -493 ml to +648 ml.
Graph 2.3
– Pre op VO2 max vs Predicted VO2 max and actual VO2 max
The mean difference between actual and predicted postoperative VO2 max was -102.12 ml/kg/min.
1519.92
actual post op VO2 max =1276.08 1519.92
PPO VO2 max = 1173.96
0 200 400 600 800 1000 1200 1400 1600
V O 2 P E A K P R E O P V O 2 P E A K P O S T O P
M
EA
N
PPO DLCO VS ACTUAL POST OP DLCO
Graph 2.4
Range of predicted postoperative DLCO from the actual postoperative DLCO is
Graph 2.5 -
– Pre op DLCOvs Predicted DLCO and actual DLCO
The mean difference between actual and predicted post-operative DLCO was -1.41 litres.
8.3695 actual post op DLCO
= 8.0264 8.3695
PPO DLCO = 6.6317
0 1 2 3 4 5 6 7 8 9
D L C O P R E O P D L C O P O S T O P
[image:68.595.76.508.130.440.2]M EA N
DLCO
Table 5.2
Correlations
PPO Values VO2 max post op Correlation Coefficient .449Sig. (2-tailed) .020
N 25
DLCO post op Correlation Coefficient .493 Sig. (2-tailed) .003
Table 6.1
Variables Pre op – Mean +/- Standard deviation (L)
Post op mean - Mean +/- Standard deviation (L)
P value (mean difference)
FVC 2.974±0.768 2.549±0.72 0.000
FVC % 85.82±17.44 71.63±19.24 0.000
FEV-1 2.406±0.634 2.002±0.548 0.000
FEV-1 % 81.57±18.835 67.94±17.098 0.000
FEV1/FVC 80.791±7.686 79.356±9.169 0.000
PEFR 6.854±1.809 6.234±1.731 0.000
TLC 4.371±1.021 3.963±1.027 0.000
RV 1.314±0.414 1.284±0.566 0.010
DSP 408.744±64.774 434.047±62.918 0.000
6 MIN W.D 416.21±59.683 445.65±64.161 0.000
6 MIN W.D % 65.65±11.725 70.24±11.307 0.000
VO2 peak 1519.92±350.629 1276.08±279.332 0.001
Vo2 peak per kg 26.004±5.239 21.328±4.461 0.012
A.T 1293.36±357.675 1084.48±241.584 0.005
VE/VCO2 34.112±6.731 34.488±5.719 0.000
DLCO 8.3695±2.237 8.0264±1.819 0.000
DLCO/VA 2.2901±0369 2.4572±0.415 0.000
SGRQ-1 34.9082±23.667 19.3143±17.713 0.873
SGRQ-2 32.5659±28.493 29.1051±27.383 0.128
SGRQ-3 22.3502±17.691 13.4653±14.449 0.109
SGRQ-Total 27.4498±19.471 19.1918±16.897 0.068
FVC – Forced vital capacity; FEV-1 – Forced expiratory volume in the first second; PEFR – peak expiratory flow rate; TLC – Total lung capacity; RV – Residual volume; 6 MIN W.D – six minute walk distance; DSP – Distance saturation product; VO2 peak – maximum rate of oxygen consumption during incremental exercise; O2 pulse per H.B – Oxygen pulse per heart beat; A.T– Anaerobic Threshold; VE/VCO2 – Ventilatory equivalent ratio for Carbon dioxide; DLCO – Diffusion capacity of lung for carbon monoxide; DLCO/VA – Diffusion capacity of lung for carbon monoxide per alveolar volume ventilated; SGRQ – St George Respiratory Questionnaire.
Graphical representation of changes – pre op to post op:
Graph 3.0– FVC Pre op vs Post op
P value = 0.000
Graph 3.1– FVC% Pre op vs Post op
P value = 0.000
2.9741 2.5494 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1
FVC pre op FVC post op
Me an
FVC
85.8245 71.6273 60 65 70 75 80 85 90FVC % pre op FVC % post op
Me
an
Graph 3.2- FEV-1% Pre op vs Post op
P value = 0.000
Graph 3.3– FEV-1/FVC Pre op vs Post op
P value = 0.000
81.5735 67.9449 0 10 20 30 40 50 60 70 80 90
FEV1 % pre op FEV1 % post op
ME AN
FEV1%
80.7916 79.3563 78.5 79 79.5 80 80.5 81FEV1 / FVC pre op FEV1 / FVC post op
ME
AN
Graph 3.4– PEFR Pre op vs Post op (l/min)
P value = 0.000
Graph 3.5– TLC Pre op vs Post op
P value = 0.000
6.8547 6.2349 5.9 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 7
PEFR pre op PEFR post op
PE FR
PEFR
4.3705 3.9625 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 4.5TLC pre op TLC post op
ME
AN
Graph 3.6– RV Pre op vs Post op
P value = 0.010
Graph 3.7– DSP Pre op vs Post op
P value = 0.000
1.3135 1.2835 1.265 1.27 1.275 1.28 1.285 1.29 1.295 1.3 1.305 1.31 1.315 1.32
RV pre op RV post op
Me an
RV
408.744 434.047 395 400 405 410 415 420 425 430 435 440Dist saturation product pre op Dist saturation product post op
Me
an
Graph 3.8– 6 min walk distance Pre op vs Post op
P value = 0.000
Graph 3.9– 6 min walk distance percentage Pre op vs Post op
P value = 0.000
416.21 445.65 400 405 410 415 420 425 430 435 440 445 450
6 Min walk distance pre op 6 Min walk distance post op
Mea
n
6 min walk distance
65.6498 70.2424 63 64 65 66 67 68 69 70 71
6 Min walk distance pre op percentage 6 Min walk distance post op percentage
Me an p erce n ta ge
Graph 3.10 – VO2 peak per kg Pre op vs Post op
P value = 0.012
Graph 3.11– AT Pre op vs Post op
P value = 0.05
26.004 21.328 0 5 10 15 20 25 30
Vo2 peak per KG pre op Vo2 peak per KG post op
Me
an
VO2 peak per kg
1293.36 1084.48 950 1000 1050 1100 1150 1200 1250 1300 1350
AT pre AT post
Me
an
Graph 3.12– VE/VCO2 Pre op vs Post op
P value = 0.005
34.112
34.488
33.9 34 34.1 34.2 34.3 34.4 34.5 34.6
VE/VCO2 pre VE/VCO2 post
Me
an
Graph 3.13– DLCO Pre op vs Post op
P value = 0.000
Graph 3.14– DLCO/VA Pre op vs Post op
P value = 0.000
8.3695 8.0264 7.8 7.9 8 8.1 8.2 8.3 8.4
DLCO pre op DLCO post op
Me an
DLCO
2.29 2.4572 2.2 2.25 2.3 2.35 2.4 2.45 2.5DLCO / VA pre DLCO /VA post
Me
an
Graph 3.15– SGRQ-1 = Symptoms score – Pre op vs post op
P value = 0.873
Graph 3.16– SGRQ-2 = Activity score– Pre op vs post op
P value = 0.128
34.9082 19.3143 0 5 10 15 20 25 30 35 40
SGRQ pre 1 SGRQ post 1
Me an
SGRQ-1
32.5659 29.1051 27 28 29 30 31 32 33SGRQ pre 2 SGRQ post 2
Me
an
Graph 3.17– SGRQ-3 = Impact score– Pre op vs post op
P value = 0.109
Graph 3.18– SGRQ – Total – Pre op vs post op
P value = 0.068
22.3502
13.4653
0 5 10 15 20 25
SGRQ pre 3 SGRQ post 3
Me
an
SGRQ-3
27.4498
19.1918
0 5 10 15 20 25 30
SGRQ pre total SGRQ post total
Me
an
The following post-operative parameters showed improvement post lung resection surgery:
Distance Saturation produce – DSP
Six minute walk distance – 6 MIN W-D
Six minute walk distance percentage – 6 MIN W-D %
Diffusion capacity of lung for CO/VA ratio – DLCO/VA
SGRQ-1 – Symptoms score
SGRQ-3 – Impact score
SGRQ-TOTAL – combined scores of SGRQ-1+2+3
DISCUSSION
In this study males comprised 55 males (55%) of total patients included, as compared to the study done by Brock et al in 2003 where 44 males comprised 65% of the selected patients(7).The mean age of patients included in our study was 41.94 +/- 12.124 years.
Sixteen patients (16%) were smokers and all were males. Out of the 37 patients who had malignancy needing lung resection surgery only 5 patients admitted to history of smoking. It is well known that tobacco smoking is the most common risk factor for lung cancer. Smoking also predisposes to COPD with resultant reduced lung function. It is quite possible that many of the lung cancer patients were smokers with COPD and thus got excluded from lung resection surgery due to poor lung function. Out of the 19 cases of Aspergilloma who underwent lung resection surgery, 8 patients had history of smoking.
(27% of malignant cases), followed by adenocarcinoma – 9 patients (24% of malignant cases).
Out of 72 lobectomies planned only 69 pure lobectomies performed. For these 6 patients, decisions were made on table, based on intra operative findings and resectabilityto change to a combination surgery, for example a lobectomy with a segmentectomy or a lobectomy with a wedge resection. Six pneumonectomies were planned and all six patients underwent pneumonectomy only.
The mean value of FEV-1 for patients included in the study was 2.28 litres +/- 0.629. FEV-1 more than 80% of predicted FEV-1 was observed in 54 patients (54%). This was an important finding as a previous study done by Feguson et al showed that when lung function was dichotomized as < 80% and > 80%, pre-operative FEV-1% was a significant predictor of overall survival after other covariates were adjusted for(11). The pre-operative FEV-1 of the 2 patients who expired were 2.83 l(106.0 of FEV-1% predicted) and 2.09 l (82.70 of FEV-1% predicted) respectively.
The mean duration of ICU stay was 44.4 hours. This was longer than that observed in an observational study done in Iceland for patients undergoing non-pneumonectomy lung resection surgeries where the median length of stay in the ICU was 24 hours(18).
Post-operative fever was observed in 7% of patients. In a study published by the British medical journal, it was observed that 2.2% of patients undergoing lobectomy had pneumonia(which included documented fever more than 37.7 degree centigrade)(19). The higher rate of post-operative fever observed in our patient population could be due to the fact that more resection surgeries are done for post infectious sequelae as compared to western countries.
Post-operative physiotherapy and incentive spirometry was done in all patients included in the study. It is recommended that incentive spirometry be initiated few days prior to surgery as these patients are prone to bronchial secretions.
None of the pulmonary function tests could predict the development of post-operative bronchopleural fistula.The incidence of bronchopleural fistula occurring after pulmonary resection has been reported to be 1.5% to 28%(16). This variability has been attributed to difference in etiology, the surgical technique and experience of the surgeon. In our study it was observed that 23% patients developed air leak with 5 out of these 23 patients having prolonged air leak of more than 7 days.
The ratio of FEV-1/FVC was found to be statistically significant for predicting prolonged duration of ICU stay with a p value of 0.024 and a Correlation Coefficient of -0.226, implying that lower the FEV-1/FVC ratio, longer was the duration of ICU stay. There is no current literature that gives value to this ratio for predicting post-operative function and complications, however it remains an important spirometry data and the key parameter to distinguish obstructive diseases from restrictive pathology. It is important to identify and treat obstructive lung disease during the perioperative period.
Post-operativelyhe had prolonged air leak, post-operative fever andatelectasis. He finally had a stump blow out which lead to septic shock. He expired 11 days post-surgery. The other patient underwent lobectomy for malignancy.She did not have intra operative or post-operative complications. However, just before her routine 3 month follow-up, it was informed to us that she had a sudden death while at home.The cause of her sudden death was unknown. This was comparable to the study done by Green et al where the 30 day follow up reported 2% mortality while the 3 month follow up reported 5% mortality(20). This reassures us that our existing protocols of patient selection and post-operative care is able to achieve very low mortality as comparable to other published series.
For the 48 patients who returned for follow up and post-operative pulmonary function testing, we compared the predicted post-operative FEV-1(PPO FEV-1) with actual post-operative FEV-1. There was a strong correlation, with Spearmans Correlation Coefficient of 0.838 which indicated close association of predicted vs the actual post-operative values. It was observed that predicted post-post-operative lung function had a mean difference of-76 ml to + 76 ml of the actual post-operative FEV-1 values,
For the 35 patients who underwent testing for DLCO, predicted DLCO max was found to be within the range of -1.28 litres to +6.19 litresof the actual post-operative DLCO. The Correlation Coefficient was 0.493 which indicated a poor association between predicted and actual post-operative values.
While comparing the pre-operative tests versus the post-operative parameters, one of the significant observations was that some of the exercise testing parameters improved after lung resection surgery. This is probablybecause removing the diseased part of the lung parenchyma had resulted in improvement in physiology and therefore improvement in exercise capacity. This was further evident while comparing the DLCO parameters where although DLCO had decreased post-operatively, the ratio of DLCO/VA(DLCO for alveolar volume ventilated) had improved.
LIMITATIONS
Following were the limitations of the study
:
1. Technical difficulties – There were times when the treadmill used for cardiopulmonary exercise testing was out of order and hence patients included towards the end of the study and most patients on follow up could not perform exercise testing. Only 25 patients had both pre-operative and post-operative cardiopulmonary exercise testing.
2. Hawthorne effect - There was no blinding of patients or investigators. The operating Thoracic surgeon also was not blinded and hence there was a theoretical possibility of less post-operative complications occurring.
CONCLUSIONS
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