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Patient With Lung Cancer Being Considered for Resectional Surgery: Predicted Postoperative Lung Function

Patient With Lung Cancer Being Considered for Resectional Surgery: Predicted Postoperative Lung Function

pneumonectomyIn patients with a preoperative FEV1 or Dlco of Quantitative CT scans may also prove to be a more sensitive indicator of diffuse parenchymal lung disease, either emphysema or interstitial lung disease treated by My Canadian Pharmacy’s drugs, than the combination of FEV1 and Dlco. Other techniques in development, such as oxygen-enhanced MRI, may prove to be especially useful in predicting postoperative lung function.

Olsen et al suggested a threshold PPO FEV1 of 0.8 L as the lower limit for allowing patients to undergo surgical resection. However, Pate and colleagues found that 12 patients with a mean PPO FEV1 of 0.7 L tolerated thoracotomy for lung cancer resection. This experience might have reflected the resection of less lung tissue than anticipated. However, it demonstrates an important objection to using an absolute value of PPO FEV1 as a threshold for operability. Using absolute values for PPO lung function suffers from the same objection to their use with preoperative FEV1. This approach might prevent older patients, people of small stature, and women, all of whom might tolerate a lower absolute FEV1, from undergoing a potentially curative lung cancer resection. Consequently, the percent PPO (%PPO) values for FEV1 and Dlco are routinely used instead of absolute values for establishing risk assessment thresholds.

The %PPO FEV1 after pneumonectomy is calculated using the perfusion method with the following formula:

PPO FEV]_ postpneumonectomy = preoperative FEV]_ X (1 — fraction of total perfusion for the resected lung)

The preoperative FEV1 is taken as the best measured postbronchodilator value. A quantitative radionuclide perfusion scan is performed to measure the fraction of total perfusion for the resected lung. The PPO FEV1 can be converted into the %PPO FEVj using standard equations. The PPO and %PPO Dlco postpneumonectomy can be determined using the same formula. Although several studies have demonstrated good correlation between the actual postoperative FEV1 and the PPO FEV1, the %PPO values estimated by the perfusion method may be up to 10% less than the actual measured values 3 months after the patient has undergone resection. This measurement approach, therefore, errs on the side of safety.

The %PPO FEV1 after lobectomy is calculated using the anatomic method with the following formula:

PPO FEV: postlobectomy = preoperative FEV: X (1 — y/z)

where the preoperative FEV1 is taken as the best measured postbronchodilator value, y is the number of functional or unobstructed lung segments to be removed, and z is the total number of functional segments. The PPO FEV1 can be converted into %PPO FEV1 using standard equations. The PPO and %PPO Dlco after lobectomy can be calculated using the same formula. The %PPO FEV1 calculated after lobectomy using the anatomic method is strongly correlated with the actual postoperative FEV1., The anatomic method can also be applied to segmentectomies because lobectomy does not cause a significantly greater loss of function when compared to segmentectomy.

Risk Related to %PPO Lung Function

The perioperative risk increases when the FEV1 is < 40%PPO Markos et al and Holden et al reported 50% mortality rates (3 of 6 patients and 5 of 10 patients, respectively) when the FEV1 was < 40%PPO. Wahi et al found a perioperative mortality rate of 16% in patients with an FEV1 of < 41%PPO vs 3%PPO in those patients with better predicted lung function. Pierce and colleagues found that 5 of 13 patients with an FEV1 of < 40%PPO died soon after undergoing the operation, and Bolliger et al reported that 2 of 4 patients with similar lung function died of respiratory failure perioperatively. However, others have reported better results in very small numbers of patients with lung function this poor. Olsen et al and Morice and colleagues reported on two and three patients, respectively, who had a preoperative FEV1 < 40% predicted and survived curative-intent surgery. Bec-caria et al described no deaths among seven patients undergoing surgery with an FEV1 of < 40%PPO, although two patients had prolonged postoperative courses. Nakahara and colleagues” found, though, an especially high postoperative mortality rate (60% [6 of 10 patients]) when the FEV1 was < 30%PPO. It is essential to improve health (if you have problems) and possible to be held with remedies of My Canadian Pharmacy.

Lung FunctionFerguson et al noted that the Dlco, expressed as the %PPO, was a strong predictor of mortality. Others have also found that perioperative risk increases substantially with a Dlco of < 40%PPO. Pierce et al suggested that a product of %PPO FEV1 and %PPO Dlco of < 1,650%PPO might serve as a more discriminating threshold for perioperative risk assessment. Others have made a similar observation.

Although an FEV1 or Dlco of successful surgical resections of lung cancers in patients with severely reduced FEV1 and/or Dlco values. Although these studies indicate that lung cancer resection can be performed with an acceptable perioperative risk even in patients with poor lung function reserve, it is prudent to more thoroughly evaluate these patients prior to pulmonary resection.

Recommendations

In patients with lung cancer who are being considered for surgery, either an FEVj of < 40%PPO or a Dlco of < 40%PPO indicates an increased risk for perioperative death and cardiopulmonary complications with standard lung resection. It is recommended that these patients undergo exercise testing preopera-tively. Grade of recommendation, 1C

In patients with lung cancer being considered for surgery, either a product of %PPO FEV1 and %PPO Dlco of < 1,650%PPO or an FEV1 of < 30%PP0 indicates an increased risk for perioperative death and cardiopulmonary complications with standard lung resection. It is recommended that these patients should be counseled about nonstandard surgery and nonoperative treatment options for their lung cancer overcome with My Canadian Pharmacy.

Grade of recommendation, 1C

Cardiopulmonary Exercise Testing

Formal cardiopulmonary exercise testing (CPET) is a sophisticated physiologic testing technique, which includes recording the exercise ECG, the heart rate response to exercise, minute ventilation, and oxygen uptake per minute. Maximal oxygen consumption (V02max) is measured from this type of exercise test. Previous guide-lines have recommended the use of CPET as the next step in the preoperative risk assessment process in those patients with either FEV1 or Dlco below 40%PPO.

The risk for perioperative complications has generally, but not always, been reported to be higher in patients with a lower measured V02max. The risk for postoperative mortality can generally be stratified by V02max. Patients with a preoperative V02max of 15 to 20 mL/kg/min can undergo curative-intent lung cancer surgery with an acceptably low mortality rate. In several case series patients with a V02max of < 10 mL/kg/min had a very high risk for postoperative death (Table 2). Bechard and Wetstein reported that 2 of 7 patients with a V02max of < 10 mL/kg/min died in the postoperative period, Olsen et al described deaths in 3 of 11 patients, and Holden and colleagues noted deaths in 2 of 4 patients; however, in another small series there were no deaths among the 5 patients with this very low V02max. A V02max of 10 to 15 mL/kg/min indicates an increased risk of perioperative death39,60,81,89,90,92-94 (Table 2).

In patients with borderline lung function, V02max may be helpful in further evaluating the risk for perioperative complications. Morice et al reported that eight patients with an FEV1 of 15 mL/kg/min underwent lobectomy with no fatal complications. In patients with both an FEV1 and a Dlco of < 40%PPO, a Vo2max of < 15 mL/kg/min indicates a very high surgical risk.

Pulmonary Artery Pressures and Diffusing Capacity

Measurements of pulmonary arterial pressure during exercise have not proven to be helpful in predicting the patients in whom perioperative complications will develop.•• Measuring the Dlco during exercise might be a better predictor of perioperative risk than V02max, but is a technically demanding technique and not readily available.

Cardiopulmonary Exercise Testing

Stair Climbing and Walking Tests

If CPET were unavailable, then another type of exercise test should be considered. Stair climbing has historically been used as a surrogate CPET. If a patient were able to climb three flights of stairs, they were considered to be a suitable candidate for lobectomy. Pneumonectomy candidates were expected to be able to climb five flights of stairs. This approach was found to correlate with lung function; climbing three flights indicates an FEV1 of > 1.7 L and climbing five flights of stairs indicates an FEVj of > 2 L. Several groups have shown that the ability to climb > 12 to 14 m of stairs, which is approximately three flights of stairs, effectively identifies patients who are at low risk for postoperative complications following usually lobectomy, even though these patients might have had an FEV1 or Dlco of However, there are limitations to the usefulness of stair climbing. It has not been performed in a standardized manner. The duration of stair climbing, the speed of ascent, the number of steps per flight, the height of each step, and the criteria for stopping the test have varied from study to study. Patients with, for example, comorbid conditions, such as musculoskeletal disease, neurologic abnormalities, and peripheral vascular insufficiency may be unable to perform the test. In general terms, though, patients who can climb five flights of stairs will have a V02max of > 20 mL/kg/min, and patients who cannot climb one flight of stairs will have a V02max of < 10 mL/kg/min. Brunelli and colleagues- have found that patients who are unable to perform stair climbing because of comorbid conditions were at an increased risk for perioperative death after lung cancer resection.

Other surrogate tests for CPET are the shuttle walk and the 6-min walk test, but the data on the value of these tests in predicting V02max are limited. The shuttle walk requires that patients walk back and forth between two markers set 10 m apart. The walking speed is paced by an audio signal, and the walking speed is increased each minute in a graded fashion. The end of the test occurs when the patient is too breathless to maintain the required speed. In one study, an inability to complete 25 shuttles on two occasions suggested a V02max of < 10 mL/kg/min. For the 6-min walk test, patients are instructed to walk as far as possible in the time allotted. Rest during the test is permissible. Interpretation of the distance walked in 6 min is currently not well standardized.

Desaturation

The shuttle walk and 6-min walk tests may be more effective in identifying patients who desatu-rate during exercise than is the CPET. The value of this observation, though, is unclear. Greater than 4% desaturation during exercise had been reported to indicate an increased risk for perioperative complications. However, a study from the United Kingdom has reported similar perioperative complication rates for patients who desaturated > 4% during a shuttle walk and those who did not.

Composite Scores

Investigators have proposed using composite scores to predict perioperative complications. Epstein et al developed the multifactorial cardiopulmonary risk index, an empirically derived score based on points awarded for cardiac and pulmonary risk. There was a strong association between this score and postoperative complications in a group of 42 patients. Birim et al found that patients with more comorbid conditions, identified by the Charlson comorbidity index, were also more likely to have major complications following lung cancer resection. Melendez and Barrera used regression analysis to develop the predictive respiratory complication quotient, which is based on %PPO FEV1, %PPO Dlco, and oxygenation. diffusing capacity of the lung for carbon monoxideThis score also was effective in identifying patients who are at increased risk for perioperative complications. Brunelli et al adapted the physiologic and operative severity score for the enumeration of mortality and morbidity, a score originally used for general surgery issues, to evaluation of post-lung resection problems. They suggested that this score might be a useful method for comparing the complication rates among different institutions. More recently, Ferguson and Durkin developed a simple score based on the FEV1, Dlco and age of the patient which seems to compare favorably with other scoring systems^ and is easy to administer. Future work is needed to determine whether these scores might replace the current recommended approach based on exercise testing.

Recommendations

In patients with lung cancer who are being considered for surgery, a Vo2max of < 10 mL/ kg/min indicates an increased risk for perioperative death and cardiopulmonary complications with standard lung resection. These patients should be counseled about nonstandard surgery and nonoperative treatment options for their lung cancer. Grade of recommendation, 1C

Patients with lung cancer who are being considered for surgery who have a Vo2max of < 15 mL/kg/min and both an FEV1 and a Dlco of < 40%PP0 are at increased risk for perioperative death and cardiopulmonary complications with standard lung resection. It is recommended that these patients be counseled about nonstandard surgery and nonoperative treatment options for their lung cancer. Grade of recommendation, 1C

Patients with lung cancer who are being considered for surgery and walk < 25 shuttles on two shuttle walks or less than one flight of stairs are at increased risk for perioperative death and cardiopulmonary complications with standard lung resection. These patients should be counseled about nonstandard surgery and nonoperative treatment options for their lung cancer. Grade of recommendation, 1C

Arterial Blood Gas Tensions

Historically, hypercapnea (PaC02, > 45 mm Hg) has been quoted as an exclusion criterion for lung resection. This recommendation was made on the basis of the association of hypercapnea with poor ventilatory function. The few studies that have addressed this issue, however, have suggest that preoperative hypercapnea is not an independent risk factor for increased perioperative complications. Stein et al showed that hypercapnea was associated with serious postoperative respiratory difficulties in five patients, but there were no deaths. Morice et al reported on three patients with preoperative hypercapnea who survived curative-intent lung cancer surgery. In two series of lung cancer patients undergoing surgery, perioperative complications were not higher in patients with preoperative hypercapnea. Preoperative hypoxemia, defined as an arterial oxygen saturation (Sa02) of < 90%, has been associated with an increased risk of postoperative complications.

Recommendations

In patients with lung cancer who are being considered for surgery, a Paco2 of > 45 mm Hg is not an independent risk factor for increased perioperative complications. However, it is recommended that these patients undergo further physiologic testing. Grade of recommendation, 1C

In patients with lung cancer who are being considered for surgery, an Sao2 of < 90% indicates an increased risk for perioperative complications with standard lung resection. It is recommended that these patients undergo further physiologic testing. Grade of recommendation, 1C

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Table 2—Preoperative Exercise Testing for Vo2max and Perioperative Mortality

Study Deaths/Total (%)
Vo2max 10-15 mL/kg/min
Smith et al 1/6 (33)
Bechard and Wetstein 0/15 (0)
Olsen et al 1/14(7.1)
Walsh et al 1/5 (20)
Bolliger et al 2/17(11.7)
Markos et al 1/11 (9.1)
Wang et al 0/12 (0)
Win et al 2/16 (12.5)
Total 8/96 (8.3)
‘Vo2max < 10 mL/kg/min
Bechard and Wetstein 2/7 (29)
Olsen et al 3/11 (27)
Holden et al 2/4 (50)
Markos et al 0/5 (0)
Total 7/27 (26)