Randomized clinical trial of prehabilitation in colorectal surgery

BACKGROUND

'Prehabilitation' is an intervention to enhance functional capacity in anticipation of a forthcoming physiological stressor. In patients scheduled for colorectal surgery, the extent to which a structured prehabilitation regimen of stationary cycling and strengthening optimized recovery of functional walking capacity after surgery was compared with a simpler regimen of walking and breathing exercises.

METHODS

Some 112 patients (mean(s.d.) age 60(16) years) were randomized to either the structured bike and strengthening regimen (bike/strengthening group, 58 patients) or the simpler walking and breathing regimen (walk/breathing group, 54 patients). Randomization was done at the surgical planning visit; the mean time to surgery available for prehabilitation was 52 days; follow-up was for approximately 10 weeks after surgery.

RESULTS

There were no differences between the groups in mean functional walking capacity over the prehabilitation period or at postoperative follow-up. The proportion showing an improvement in walking capacity was greater in the walk/breathing group than in the bike/strengthening group at the end of the prehabilitation period (47 versus 22 per cent respectively; P = 0.051) and after surgery (41 versus 11 per cent; P = 0.019).

CONCLUSION

There was an unexpected benefit from the recommendation to increase walking and breathing, as designed for the control group. Adherence to recommendations was low. An examination of prehabilitation 'responders' would add valuable information.

Pulmonary diffusion and aerobic capacity: is there a relation? Does obesity matter?

AIM

We sought to determine whether pulmonary diffusing capacity for nitric oxide (DLNO), carbon monoxide (DLCO) and pulmonary capillary blood volume (Vc) at rest predict peak aerobic capacity (VO2peak), and if so, to discern which measure predicts better.

METHODS

Thirty-five individuals with extreme obesity (body mass index or BMI = 50 +/- 8 kg m((-2)) and 26 fit, non-obese subjects (BMI = 23 +/- 2 kg m((-2)) participated. DLNO and DLCO at rest were first measured. Then, subjects performed a graded exercise test on a cycle ergometer to determine (VO2peak). Multivariate regression was used to assess relations in the data.

RESULTS

Findings indicate that (i) pulmonary diffusion at rest predicts (VO2peak) in the fit and obese when measured with DLNO, but only in the fit when measured with DLCO; (ii) the observed relation between pulmonary diffusion at rest and (VO2peak) is different in the fit and obese; (iii) DLNO explains (VO2peak) better than DLCO or Vc. The findings imply the following reference equations for DLNO: (VO2peak) (mL kg(-1) min(-1)) = 6.81 + 0.27 x DLNO for fit individuals; (VO2peak) (mL kg(-1) min(-1)) = 6.81 + 0.06 x DLNO, for obese individuals (in both groups, adjusted R(2 )=( )0.92; RMSE = 5.58).

CONCLUSION

Pulmonary diffusion at rest predicts (VO2peak), although a relation exists for obese subjects only when DLNO is used, and the magnitude of the relation depends on gender when either DLCO or Vc is used. We recommend DLNO as a measure of pulmonary diffusion, both for its ease of collection as well as its tighter relation with (VO2peak).

Urinary retention after total hip and knee arthroplasty

Postoperative urinary retention (POUR) occurs after lower joint arthroplasty with an incidence between 0% and 75%. This vast range reflects the differences in diagnosis and management of POUR. At present, clinical practice includes either preoperative insertion of an indwelling catheter to be removed after 24-48 postoperative hours or postoperative intermittent in-and-out catheterization performed either at scheduled times (every 6-8 hours) or as necessary. Although the most effective approach remains an issue of debate, there is a growing consensus that postoperative intermittent catheterization guided by ultrasound could decrease the incidence of complications related to POUR. The purpose of the present article is to review the published data on the effects of analgesia techniques on the development of POUR after hip and knee arthroplasty. General and regional anesthesia are implicated in the etiology of POUR; however, type and duration do not correlate with its incidence. Of the different postoperative analgesic techniques currently used, continuous peripheral nerve block has the least impact on POUR.

Pathological and molecular characteristics distinguishing contralateral metastatic from new primary breast cancer

BACKGROUND

Breast cancer patients have a cumulative lifetime risk of 2%-15% of developing a contralateral metastatic or ex novo primary cancer. From prognostic and therapeutic viewpoints, it is important to differentiate metastatic from second primary. To distinguish these entities, we investigated whether the pattern of X chromosome inactivation could determine whether the two tumors derived from different progenitor cells.

MATERIALS AND METHODS

The clonality of bilateral breast cancer was evaluated through the X-inactivation analysis using the human androgen receptor gene (HUMARA) polymorphism and the histopathologic and molecular results were compared. A different or an identical pattern of X inactivation was considered as indicator of a second primary cancer or not informative, respectively. We considered morphological indicators of a new primary cancer the absence of concordance in the histological type or a better histological differentiation.

RESULTS

Ten patients with bilateral breast cancer were evaluated. Morphological criteria indicated that eight were second primary, a conclusion confirmed by the X-inactivation analysis. Two cases classified as recurrence according to morphological criteria were classified as second tumor by molecular analysis.

CONCLUSION

Our results show that the HUMARA clonality assay can improve the histological parameters in differentiating metastatic cancer from second primary cancer.

The physiological effects of thoracic epidural anesthesia and analgesia on the cardiovascular, respiratory and gastrointestinal systems

Studies of regional anesthesia are increasing in popularity not only for the purpose of technical advancement, but also to better understand the effects of neural deafferentation on the function of various organs. Thoracic epidural anesthesia (TEA) is one of the most versatile and widely utilized neural deafferentation techniques. The aim of this article is to critically review published data regarding the most relevant effects of TEA on the cardiovascular, respiratory and gastrointestinal systems. In the cardiovascular system, TEA modifies the electrical activity of the heart in addition to ventricular function and wall motion. Improvements in regional blood flow and a reduction of the major determinants of cardiac oxygen consumption lead to less severity of the ischemic injury. Although TEA negatively affects the performance of intercostal muscles, it spares diaphragmatic function and, when it is limited to the first five thoracic segments, affects pulmonary volumes to a lesser extent. TEA can be safely used in patients with compromised respiration. Splanchnic sympathetic block is achieved when thoracic fibers from T5 to T12 are affected in a dose-dependent manner. Improved gastrointestinal blood flow and motility are clear in animals, and in clinical studies, TEA has been shown to improve recovery after major abdominal surgery. TEA thus presents a powerful tool available to anesthesiologists for perioperative intervention, but its use alone cannot prevent postoperative morbidity and mortality. It is therefore necessary to address its use in the context of multimodal intervention.

Correlation between pre-operative metabolic syndrome and persistent blood glucose elevation during cardiac surgery in non-diabetic patients

BACKGROUND

Cardiopulmonary-bypass (CPB) induces hyperglycemia. There is growing evidence that perioperative maintenance of blood glucose within the physiological range improves patients' outcome. Nevertheless, perioperative normoglycemia is often difficult to achieve during surgery with CPB and the response to insulin infusion is characterized by a considerable variability. The aim of this study was to determine to what extent the presence of pre-operative metabolic syndrome (MS) influences the blood glucose and insulin response during cardiac surgery.

METHODS

Forty-five patients scheduled for elective cardiac surgery were screened for the presence of MS according to the International Diabetes Federation definition. Patients were then assigned to two groups: those with metabolic syndrome (MSP) and those without (control). During surgery, blood glucose levels were measured in all patients and hyperglycemia was treated with a standard protocol of continuous insulin infusion.

RESULTS

The mean blood glucose levels during CPB increased only in the MSP group (P<0.001). Mean blood glucose in control patients did not increase during CPB (P=0.4). Patients with MS received 13.3+/-8.4 IU of insulin during CPB, while the control group did not require insulin treatment (P<0.001). Forty percent of patients in the control group and 100% of those in the MSP group developed post-operative insulin resistance. C-reactive protein was higher in the MSP group before, during and at 48 h after surgery.

CONCLUSIONS

The mean blood glucose levels during CPB increased only in patients with MS, while they remained unchanged in patients in the control group.

Depth of anesthesia with desflurane does not influence the endocrine-metabolic response to pelvic surgery

BACKGROUND

It has been reported that, with deep levels of anesthesia achieved with general anesthetic agents and opioids, post-operative consumption of morphine and pain intensity can be reduced. It is not clear whether the depth of anesthesia modifies pain intensity by influencing the endocrine-metabolic stress response. The purpose of this study was to assess the influence of a high concentration of desflurane on peri-operative plasma cortisol.

METHODS

The study was prospective and observer blinded, and included 20 women scheduled for elective total abdominal hysterectomy. They were randomly divided in to two groups: a deep group (D) (n=10) and a light group (L) (n=10). Anesthesia was induced with propofol, fentanyl and rocuronium: desflurane was administered at two different concentrations according to Bispectral Index monitoring (deep, 25 and light, 50). Post-operative pain relief was achieved with patient-controlled analgesia (PCA) with intravenous morphine. Blood samples were taken before, during and after surgery for the measurement of plasma cortisol, glucose and lactate. Post-operative pain visual analog scale (VAS) and morphine consumption were recorded at regular intervals for the first 24 h.

RESULTS

The Concentrations of plasma cortisol, glucose and lactate increased with surgery in both groups, and remained elevated, with no difference between the two groups. VAS and morphine consumptions were similar in both groups.

CONCLUSION

The results show that there is no relationship between the intra-operative level of anesthesia depth achieved with desflurane and the extent of endocrine-metabolic stress response.

Validation of esophageal Doppler for noninvasive hemodynamic monitoring under pneumoperitoneum

BACKGROUND

Commonly used perioperative measurements of hemodynamics, such as Swan-Ganz catheter assessment, are invasive and may not be reliable under pneumoperitoneum. The purpose of this study was to validate the use of esophageal Doppler for noninvasive hemodynamic monitoring under pneumoperitoneum in an experimental pig model.

METHODS

Eight female pigs were submitted to two 30-min study periods, one each for the baseline (no interventions) and pneumoperitoneum (12-mmHg carbon dioxide pneumoperitoneum) conditions. One pig was excluded because of tachycardia (>140 at baseline). A Swan-Ganz pulmonary artery catheter was used to measure cardiac output (CO-SG) and pulmonary capillary wedge pressure (PCWP). An esophageal Doppler probe was inserted to record cardiac output (CO-ED) and corrected flow time (FTc), an index of preload. Transthoracic echocardiography was used to measure left ventricular end-diastolic diameter (LVEDD) and cardiac output (CO-TTE). Pearson correlation was used to assess individual associations between the measured hemodynamic parameters.

RESULTS

There was good correlation between CO-ED and CO-SG (r = 0.577; p < 0.001) and excellent correlation between CO-ED and CO-TTE (r = 0.815; p < 0.001). There was no correlation between FTc and LVEDD or PCWP. These relationships were consistent when analyzed separately at baseline and during pneumoperitoneum.

CONCLUSION

Esophageal Doppler monitoring is a valid noninvasive method of estimating cardiac output at baseline and during pneumoperitoneum in a porcine model. Corrected flow time did not correlate with other estimates of preload at baseline or during pneumoperitoneum.