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PubMed2006

Minimally invasive versus standard approach aortic valve replacement: a study in 506 patients.

BACKGROUND: Minimally invasive aortic valve replacement through partial upper sternotomy has been shown to reduce surgical trauma, and, supposedly, decrease postoperative pain, blood loss, and hospital stay. METHODS: From October 1997 until November 2004, 506 patients received isolated aortic valve replacement, of which 232 underwent the minimal access J-sternotomy approach (group 1). The control group (group 2) consisted of 274 patients who underwent aortic valve replacements by median sternotomy. We retrospectively reviewed outcomes of the patients in the early follow-up period. RESULTS: In group 1 and group 2, respectively, early mortality was 2.6% (6 patients) and 4.4% (12 patients). The minimal access group had reduced aortic cross-clamp and cardiopulmonary bypass times compared with conventional group: 61.8 +/- 16.6 versus 69.5 +/- 16.6 minutes (p < 0.05) and 88.8 +/- 23.2 versus 100.2 +/- 22.6 minutes (p < 0.05), respectively. Mean blood loss was lower in group 1 compared with group 2 (p < 0.05). Intensive care unit and hospital stays were shorter in the minimal access group: 2.1 +/- 2.5 versus 2.5 +/- 5.3 days (p = nonsignificant) and 10.8 +/- 7.1 versus 12.8 +/- 10.6 days (p < 0.05), respectively. CONCLUSIONS: Aortic valve replacement can be performed safely through a partial upper sternotomy on a routine basis for isolated aortic valve disease.

Aged↗
PubMedDate not supplied

Radiation pericarditis and breast reconstruction: a surgical dilemma.

OBJECTIVE: To discuss a case of radiation pericarditis and the physiology of the disease, and to discuss the left thoracotomy as an effective alternative to median sternotomy for pericardiectomy in the treatment of complicated radiation pericarditis. DESIGN: A case report with accompanying discussion of the disease and literature search. SETTING: Keesler Air Force Base Medical Center, a military training facility and general surgery residency program. PARTICIPANTS: A single case report with review of literature. RESULTS: Left thoracotomy is an effective alternative to median sternotomy for the surgical treatment of radiation pericarditis, with a mild increase in pulmonary-associated complications. CONCLUSIONS: With an increase in the use of mediastinal radiation for treatment of malignant disease as well as the increase in women having reconstructive procedures of the breast, one may expect complicated cases of radiation pericarditis that may not be amenable to median sternotomy. Left thoracotomy may be an alternative to median sternotomy for pericardiectomy in cases of pericarditis complicated by cosmetic constraints.

Breast Neoplasms↗
PubMed2005

The surgical approach to retrosternal goiters: the role of computerized tomography.

OBJECTIVE: To assess preoperative CT scans of patients with a retrosternal goiter, with an objective of identifying features that are likely to predict the need for sternotomy at operation. STUDY DESIGN AND SETTING: A retrospective review of clinical notes and CT scans of patients who underwent thyroidectomy for retrosternal goiter at a large district general hospital in the United Kingdom between 1998 and 2002. RESULTS: Extension of the goiter to the level of the aortic arch, particularly when combined with tracheal involvement or major vessel displacement, increases the likelihood of requiring median sternotomy. CONCLUSIONS: Most retrosternal goiters can be approached through a cervical incision alone. However, extension of the goiter to the level of the aortic arch does appear to increase the likelihood of requiring sternotomy. SIGNIFICANCE: In such cases in which sternotomy is anticipated, the availability of cardiothoracic services would be helpful to avoid patient morbidity.

Adult↗
PubMed2000

Repeated procedure after radical surgery for tetralogy of Fallot.

BACKGROUND: Although the immediate results of radical operation for tetralogy of Fallot are excellent, long-term follow-up has shown that the number of repeated procedures has increased in many institutions. We describe patients who underwent a second or third procedure after radical operation for tetralogy of Fallot. METHODS: Between April 1981 and August 1996, we operated on 44 patients for the second time and on 4 for the third time after radical operation for tetralogy of Fallot. Indications for a second and third procedure included right ventricular outflow tract obstruction in 38 patients, infective endocarditis in 4, and isolated residual ventricular septal defect in 3. RESULTS: One patient died after concomitant replacement of the pulmonary and tricuspid valves. Three patients who underwent sternotomy more than twice (before the second or third operation) underwent accidental cardiovascular trauma during this procedure (30%). Moreover, when patients underwent more than two sternotomy procedures before the repeated operation for tetralogy of Fallot, the total bypass time, interval between cessation of the cardiopulmonary pump to completion of the operation, amount of blood transfusion, and length of intensive care unit stay were significantly higher compared with those who underwent less than two sternotomy procedures (p < 0.05). Right ventricular outflow tract obstruction was the main indication for a second operation. After the second operation for right ventricular outflow tract obstruction in 35 patients, the preoperative right ventricle to left ventricle pressure ratio decreased significantly (from 0.75 +/- 0.13 to 0.51 +/- 0.12; p < 0.0001). However, the right ventricle to left ventricle pressure ratio did not significantly decrease in patients who underwent a third procedure to treat right ventricular outflow tract obstruction. CONCLUSIONS: The surgical results of a second procedure after radical operation for tetralogy of Fallot were acceptable. However, the risk of accidental cardiovascular trauma during dissection was high among patients who underwent sternotomy more than twice before repeat operation.

Adolescent↗
PubMed2001

Minimally invasive video-assisted mitral valve surgery: our lessons after a 4-year experience.

BACKGROUND: Right thoracotomy is a well known alternative to median sternotomy to gain access to the left atrium. To avoid the potential drawbacks associated with sternotomy coupled to the desire for a smaller scar and a more rapid rehabilitation in young and active patients, we investigated the purported advantages in patients undergoing video-assisted Port-Access mitral valve surgery. METHODS: Between February 1997 and November 2000, 175 patients (94 men, 81 women) with a mean age of 60 years (range 25 to 84) underwent either Port-Access mitral valve repair (n = 117) or replacement (n = 57) for degenerative disease (n = 112), rheumatic disease (n = 36), chronic endocarditis (n = 15), annular dilatation (n = 8), sclerotic disease (n = 2), and ingrowing myxoma (n = 1). There was one closure of a preexisting paravalvular leak. Standard Carpentier-Edwards repair procedures were used in all patients; in 14 patients polytetrafluoroethylene chordae were inserted for anterior leaflet prolapse. A total of 74 patients (42%) were in New York Heart Association functional class III/IV. RESULTS: Hospital mortality was 1.1% (n = 2). Four patients had conversion to sternotomy and conventional extra corporeal circulation for repair of a dissected aorta (n = 2) or the inabilty to proceed to a safe femoral cannulation (n = 2). Sixteen patients (9%) underwent a revision for bleeding. Mean cross-clamp time and perfusion time was 95 minutes (range 24 to 160) and 135 minutes (range 75 to 215) respectively. Mean intensive care unit and total hospital stay was 1.8 days (1 to 30) and 8.7 days (4 to 36), respectively. Three patients experienced late acute endocarditis: 2 had late mitral valve replacements and 1 patient had medical therapy for late prosthetic valve endocarditis. There were no myocardial infarctions, cerebrovascular events or peripheral ischemia due to thromboembolic phenomena. No wound complications were observed. The degree of patient satisfaction was very high. CONCLUSIONS: The video-assisted Port-Access mitral valve approach is a valid alternative to sternotomy, with the same standards of results and quality.

Adult↗
PubMed2003

Mediastinitis in heart and lung transplantation: 15 years experience.

BACKGROUND: Mediastinitis after sternotomy carries a very high mortality, especially in patients receiving immunosuppressive treatment. METHODS: A retrospective analysis of the data for patients who had undergone cardiopulmonary transplantation between May 1985 and December 2000 was undertaken. A total of 776 patients had either a median sternotomy or a transverse sternotomy through a clam-shell incision. Transplantations were as follows: 591 heart (3 simultaneous heart and renal, and 1 heart and liver), 126 bilateral sequential lung, 57 heart-lung, 1 en bloc double-lung, and 1 heart and single-lung. RESULTS: In all, 21 (2.7%) recipients had mediastinitis. Of these, 14 had heart, 3 heart-lung, and 4 bilateral lung transplantation. There were 18 median and 3 transverse sternotomies. There were 6 deaths (28.6%). Treatment consisted of antibiotics alone in 2 patients and subxiphisternal drainage in another 2 patients. The sternum was reopened in 17 (80.95%) patients, with debridement and primary closure alone in 5 of these 17 patients and additional irrigation in the other 12. Those who had resternotomy, debridement, and substernal irrigation had a better outcome when compared with the outcomes of other modes of treatment (1 death among 12 patients) (p = 0.06). Age, cardiopulmonary bypass time, body mass index, time to diagnosis, and treatment did not differ between those who survived and those who did not. CONCLUSIONS: Early aggressive debridement with substernal irrigation is the best mode of treatment for patients with posttransplantation mediastinitis.

Adolescent↗
PubMed1998

Morbidity, cost, and six-month outcome of minimally invasive direct coronary artery bypass grafting.

BACKGROUND: Minimally invasive direct coronary artery bypass grafting (MIDCABG) promises to reduce the morbidity of coronary bypass, but this has not been proved. METHODS: This retrospective study compares the morbidity, mortality, cost, and 6-month outcome of patients less than 80 years old undergoing elective left internal mammary artery to left anterior descending artery bypass grafting via MIDCABG (n = 60) or sternotomy (n = 55) between January 1995 and December 1996. There were no differences between the groups in mean age, sex distribution, or preoperative risk level. The left internal mammary artery was mobilized from the fifth costal cartilage to the subclavian artery in all patients. The anastomoses were done with a beating heart in the MIDCABG group and with cardioplegic arrest in the sternotomy group. RESULTS: There were no operative deaths in either group. The MIDCABG patients had a lower transfusion incidence (10/60 [17%] versus 22/55 [40%]; p< or =0.02) and a shorter postoperative intubation time (2.1+/-4.2 versus 12.6+/-9 hours; p< or =0.0001). One patient in each group was reexplored for bleeding. Three sternotomy patients (3/55, 5%) required ventilatory support for greater than 48 hours, but no MIDCABG patient was ventilated for more than 24 hours. Median postoperative length of stay was 4 days for MIDCABG and 7 days for sternotomy. Estimated hospital costs were $11,200+/-3100 for MIDCABG and $15,600+/-4200 for CABG (p < 0.001). The reduced morbidity and cost of MIDCABG was found mostly in high-risk patients. At 6-month follow-up, 5 MIDCABG patients (5/60, 8%) had evidence of recurrent ischemia involving the left anterior descending artery, primarily the result of anastomotic stricture. CONCLUSIONS: This analysis shows that MIDCABG reduces the initial morbidity and cost of coronary bypass, but some patients require subsequent reintervention. Long-term follow-up is needed before MIDCABG can be judged better than traditional bypass, but the initial results are promising, especially in high-risk patients.

Case-Control Studies↗
PubMed1999

Mitral valve surgery after previous CABG with functioning IMA grafts.

BACKGROUND: Mitral valve surgery after previous coronary artery bypass grafting presents a challenging problem for the cardiac surgeon. An injury to patent coronary artery bypass grafts, especially internal mammary artery grafts, during reoperation via a redo sternotomy, may be fatal. Therefore, a reliable alternative to the redo sternotomy is desirable to minimize potential injury to internal mammary artery grafts. METHODS: Between February 1987 and October 1998, we performed 59 consecutive mitral valve operations after previous coronary artery bypass grafting surgery (CABG). A total of 24 patients (41%) had functioning internal mammary artery (IMA) grafts and represent the population for this study. No patients were excluded for any reason. Of the 24 patients, 20 (83%) were men. Mean age was 66+/-13 years (range 41 to 83 years) and the mean duration from CABG was 5.3+/-3.6 years (range 0.1 to 12 years). Four (17%) had functioning bilateral internal mammary artery grafts. All had 3 to 4+ mitral regurgitation (MR) at the time of mitral valve surgery and the mean preoperative ejection fraction (EF) was 40%+/-14% (range 20% to 74 %). RESULTS: Twenty-one (88%) patients underwent mitral valve surgery through an anterolateral right thoracotomy and 3 (12%) through a redo sternotomy. Twenty-two (92%) patients, including the 3 patients in whom a redo sternotomy was used, had cannulation of the femoral artery and vein. Two patients required axillary artery cannulation. All 21 patients in whom the mitral valve was approached through a right thoracotomy underwent deep hypothermia (19.6 degrees+/-2.1 degrees C, range 14 degrees to 25 degrees C) without aortic clamping, with a mean duration of CPB of 138+/-46 minutes (range 65 to 249 minutes). In 18 (75%), the MR was ischemic in origin and in 6 (25%) there was myxomatous degeneration. Nine (34%) required valve replacement and 15 (66%) underwent repair. There were no operative or hospital deaths and all patients were discharged to home or to a rehabilitation facility. There were 4 (17%) major complications. Two patients suffered respiratory failure requiring tracheotomy, 1 patient developed a perioperative MI requiring an intraaortic balloon pump and 1 developed heart block requiring a permanent pacemaker. There were no neurologic, peripheral vascular, bleeding, or wound complications. CONCLUSIONS: Reoperative mitral valve surgery in the setting of functioning IMA grafts, even in the face of depressed LV function, can be done safely and with minimal morbidity.

Adult↗
PubMed1996

Improved sternal fixation in the transsternal bilateral thoracotomy incision.

The success of bilateral sequential single-lung transplantation has led to the rebirth of the transsternal bilateral thoracotomy incision. Despite the multiple advantages of this incision over a median sternotomy for this operation, one distinct disadvantage is the high prevalence of sternal disruption at the transverse sternotomy site, which is traditionally closed with sternal wires. This disruption rate is between 20% and 40% in most institutions and can lead to significant pain and deformity in addition to slowing the postoperative recovery and increasing the risk of sternal infection. To overcome this problem we have designed and manufactured a device that provides a sound method of fixating the sternum. The device is composed of two plates, one anterior and one posterior to the sternum, that are fixed to each other and to the sternum by means of screws into internally threaded posts positioned in predrilled holes through the bone on either side of the sternotomy. All components of the device are made from titanium and a range of post lengths are available to accommodate variability in sternal thickness. The structure of the device is demonstrated. The device has now been inserted into a total of 20 patients after bilateral lung transplantation and the preliminary results suggest this is a superior technique for closure of a transverse sternotomy and support continued and routine use.

Bone Wires↗
PubMed1998

Minimally invasive aortic valve replacement.

During a consecutive 12-month period from January 1996 to January 1997 inclusive, 108 aortic valve replacements were performed by one group of surgeons in two community hospitals The majority of the valve replacements were done in combination with other procedures or were redo surgeries. Thirty-one patients had primary isolated aortic valve replacement. Fourteen patients underwent aortic valve replacement via a standard sternotomy, and seventeen patients underwent aortic valve replacement using a minimally invasive parasternal approach, as described by Dr. Cosgrove. There were no operative deaths in either group; however there was one hospital death in each of the two groups. Blood loss and postoperative pain were less in the minimally invasive group. Although the cross-clamp times were longer in the minimally invasive group, with a mean of 82.7 min as compared with 63.1 min in the standard group, the length of stay was shortened, with a median of 5 days in the minimally invasive group as compared to 7 days in the sternotomy group. In the follow-up which ranges from 4-15 months, all patients in the minimally invasive group were New York Heart Class I or II. Patients with the parasternal incisions are permitted to return to work much earlier than those with a standard sternotomy incision. The decreased blood loss and postoperative pain, combined with the anticipated ease of re-entry via a median sternotomy in the future (should redo aortic valve replacement become necessary), make this approach our procedure of choice in isolated primary aortic valve replacement.

Aged↗
PubMed1999

Indication and patient selection in minimally invasive and òff-pump' coronary artery bypass grafting.

BACKGROUND: The selection criteria to perform 'off-pump' coronary bypass (OPCAB) grafting are not well defined. The aim of this presentation is to outline the indications and the patient selection on the basis of 2 years experience with 572 OPCAB procedures. MATERIALS AND METHODS: From November 1996 minimally invasive coronary bypass grafting was performed in 406 patients using a limited minithoracotomy for single left anterior descending artery (LAD) revascularization (group A). In 166 patients full sternotomy and OPCAB grafting for single or multiple vessel revascularization was performed (group B). RESULTS: In group A the procedure could be performed 'off-pump' together with a limited thoracotomy in 406 out of 457 patients (88.8%) who were scheduled for single graft revascularization to LAD. Exposure and quality of the LAD was good in 308/406 (76.0%) of the patients. The decision for sternotomy was made for different preoperative characteristics of these patients: Obese female patients 16/457 (3.5%), angiographic evidence of an intramyocardial running LAD 6/457% (1.4%), diffusely diseased and small LAD 11/457 (2.4%) severe COPD 3/457 (0.7%), unstable angina 11/457 (2.4%), emergency revascularization after failed PTCA 4/457 (0.8%). In 315/406 (77.8%) of the minimally invasive direct coronary artery bypass (MIDCAB)-patients exposure and quality of the LAD was good, in 97/406 (22.2%) moderate or even bad. In the latter subgroup stenosis free anastomosis was reduced (86.5%) compared to the subgroup of good exposure and quality with 98.3%. In group B selection for sternotomy and 'off-pump' procedure was made in 117/166 (70.4%) patients with a normal preoperative status (stable angina, ejection fraction > 35%) and with coronary lesions amenable for beating heart surgery (proximal RCA lesion > 80%, not calcified and well defined POD and marginal branches). In 49/166 (29.5%) decision for 'off-pump' procedure was made on the basis of a potential risk for cardiopulmonary bypass (CPB) such as acute myocardial infarction in 10/166 (6.0%), reduced ventricular function with EF < 35 in 28/166 (16.9%), calcified ascending aorta 4/166 (2.4%) or concomitant diseases 7/166 (2.5). CONCLUSION: To maintain excellent results after single LAD revascularization using the MIDCAB-approach, appropriate patient selection is crucial. Indication for sternotomy and 'off-pump' single LAD revascularization should made in those patients excluded for MIDCAB and in patients scheduled for multiple vessel-CABG who are at high risk for CPB (concomitant pulmonary, renal, neurological diseases or severely impaired left ventricular dysfunction) and have suitable target coronary arteries in term of location and quality.

Adult↗
PubMed1999

Off-pump arterial grafting: 125 cases using the Medtronic-Utrecht Octopus.

OBJECTIVES: The use of arterial grafts in coronary bypass surgery requires a high degree of cardiac stabilization, traditionally achieved with cardiopulmonary bypass and cardioplegic arrest. The Medtronic-Utrecht Octopus has recently been developed as an advanced cardiac stabilization device, based on its unique suction method for regional epicardial immobilization and retraction. The objective of this study was to investigate the feasibility of using this device to enable total arterial revascularization on the beating, working heart. METHODS: From May 1997 to November 1998, off-pump coronary artery bypass using exclusively arterial grafts was performed in 125 selected patients (108 males), aged 2682 years (mean 61.1 +/- 10.5 years). Coronary artery immobilization was achieved with the Octopus, which uses local epicardial suction and avoids cardiac compression. Aortic anastomoses were avoided: both internal thoracic arteries and the right gastroepiploic artery were used as pedicle grafts in all but one case. All radial artery grafts and one right internal thoracic artery were used as Y-grafts from the left internal thoracic artery. There were four surgical approaches: sternotomy (98 patients), left anterior small thoracotomy (20 patients), anterolateral thoracotomy (six patients) and a subxiphoid approach in one patient. RESULTS: Sternotomy: 187 grafts were performed in 98 patients (mean 1.9 grafts per patient). There were 99 grafts to anterior wall vessels, 47 grafts to posterior wall vessels and 41 grafts to lateral wall vessels. Left anterior thoracotomy: 20 patients had a single graft to the left anterior descending artery (LAD). Left anterolateral thoracotomy: three patients had a single graft to a circumflex branch, while three had composite grafts to the LAD and circumflex systems. Subxiphoid: one patient had a single graft to the posterior descending branch of the right coronary artery. There were no peri-operative deaths in any group. No patient required conversion to cardiopulmonary bypass. Three patients required conversion from a limited-access approach to sternotomy. There was one re-operation for bleeding. Postoperative stay was 27 days (mean 3.6 +/- 1.1; median 3 days) for anterior thoracotomy, 3-4 days (mean 3.5 +/- 0.6) for anterolateral thoracotomy, and 378 days (mean 6.6 +/- 8.7; median 4 days) for sternotomy. There were two late deaths in salvage patients; no patient has required cardiac intervention or re-operation. CONCLUSIONS: The Octopus maintains excellent local cardiac immobilization--enabling the routine use of arterial grafts in off-pump coronary surgery. It allows easy access to anterior wall vessels on the heart, and relatively straightforward access to the posterior wall. Circumflex branches are graftable with careful case selection and adjunctive technical maneuvers.

Adult↗
PubMed2000

Surgical treatment of pulmonary hydatid disease in children: report of 122 cases.

BACKGROUND/PURPOSE: The aim of this study was to review the authors' surgical experience in pediatric pulmonary hydatid disease focusing on clinical presentation, parenchyma saving operations, and long-term results. METHODS: One hundred twenty-two children with pulmonary hydatid cyst were treated surgically over the last 2 decades and were reviewed retrospectively. There were 66 boys and 56 girls with a mean age of 9 years. RESULTS: Pulmonary hydatid cyst was seen in 111 (91%) patients and pulmonary and hepatic cysts in 11 (9%). Lateral thoracotomy was performed in 106 (87%) patients, thoracotomy and laparotomy in 6 (5%), median sternotomy in 5 (4%), lateral thoracotomy with phrenotomy in 4 (3%), and median sternotomy with phrenotomy in 1 (0.8%). Parenchyma-saving procedures were performed in 114 patients (93%) and lung resection in 8 (7%). There was no mortality. Postoperative complication was seen in 5 patients (4%). CONCLUSIONS: Parenchyma-saving procedures without capitonnage are preferable. In patients with right or bilateral lung and coexisting cysts in the upper part of the liver, thoracotomy or median sternotomy and transdiaphragmatic approach allows the surgeon to remove the lung and liver cysts in a single operation. Median sternotomy is an alternative method for the bilateral lung hydatidosis compared with sequential thoracotomy.

Adolescent↗
PubMed2002

Mediastinitis and cardiac surgery--an updated risk factor analysis in 10,373 consecutive adult patients.

BACKGROUND: Deep sternal wound infection (DSWI) remains a serious complication after cardiac surgery. New evolving techniques including the utilization of internal mammary arteries (IMA), beating heart procedures, and minimal invasive surgery (MIC) require an updated risk factor analysis to identify high risk patients in order to improve perioperative treatment. METHODS: 10,373 consecutive patients receiving cardiac surgery between May 1996 and August 1999 were evaluated: 9,303 underwent full sternotomy whereas a minimally invasive (MIC) approach using partial sternotomy or lateral thoracotomy was used in 1,070 patients. DSWI was defined as the evidence of mediastinitis seen at reoperation along with one or more of the following: positive culture of mediastinal fluid, positive blood culture or temperature higher than 38 degrees C and/or leukocytosis. RESULTS: The overall incidence of DSWI in the "full sternotomy" group was 1.44 % (134 of 9,303). Univariate risk factor analysis showed a significant influence of IMA use, ICU / IC treatment > 5 days, postoperative ventilator time > or = 72 h, need for reexploration, diabetes, surgery time > or = 180 min, assist device implantation (including use of IABP), peripheral vascular disease and increased body mass index. Multivariate analysis identified double IMA, ICU treatment > 5 days, single IMA, diabetes, reexploration and increased body mass as significant risk factors. No mediastinitis was observed in the MIC group. CONCLUSION: As DSWI is related to sternotomy, a MIC approach should be considered for patients at high risk for DSWI. IMA takedown as a pedicled graft should be especially avoided in patients with diabetes since the risk for postoperative mediastinitis is unacceptably high in this patient group.

Aged↗
PubMed2001

Lung volume reduction surgery restores the normal diaphragmatic length-tension relationship in emphysematous rats.

OBJECTIVE: Improved respiratory muscle function is a major effect of a lung volume reduction surgery. We studied length adaptation in rat diaphragmatic muscle in an attempt to elucidate the mechanism by which diaphragmatic function improves after this controversial operation. METHODS: We developed a model of elastase-induced emphysema and bilateral volume reduction through median sternotomy in rats. Five months after emphysema induction, maximum exchangeable lung volume was determined in intubated and anesthetized control animals and animals with emphysema. Costal diaphragmatic length was measured in vivo, and the length at which maximal twitch force is generated was determined on muscle strips in vitro. Also 5 months after elastase administration, another cohort underwent volume reduction or sham sternotomy. Five months after the operation, these animals were similarly studied. RESULTS: Lung volume was increased in emphysematous rats versus control rats (50.9 +/- 1.7 vs 45.4 +/- 1.3 mL, P =.001). Lung volume was decreased in emphysematous animals that had undergone volume reduction versus sham sternotomy (44.7 +/- 0.60 vs 49.4 +/- 1.0 mL, P =.001). In situ diaphragm length (1.99 +/- 0.04 vs 2.24 +/- 0.07 cm, P =.001) and the length at which maximal twitch force is generated (2.25 +/- 0.06 vs 2.48 +/- 0.09 cm, P =.038) were shorter in emphysematous than control animals. After volume reduction, in situ diaphragm length (2.13 +/- 0.06 vs 1.83 +/- 0.02 cm, P <.001) and the length at which maximal twitch force is generated (2.50 +/- 0.08 vs 2.27 +/- 0.06 cm, P =.013) were longer than in animals undergoing sham sternotomy. CONCLUSIONS: In this experimental model of emphysema and lung volume reduction surgery, emphysema shortens the length at which maximal twitch force is generated and shifts the diaphragmatic length-tension curve to lower lengths; volume reduction returns the length at which maximal twitch force is generated toward normal and shifts the diaphragmatic length-tension curve back to longer lengths. This restoration toward normal physiology may enable the improvement in diaphragmatic function seen after lung volume reduction surgery. The mechanism by which these length adaptations occur merits further investigation.

Adaptation, Physiological↗
PubMed2003

Endotoxemia in coronary artery bypass surgery: a comparison of the off-pump technique and conventional cardiopulmonary bypass.

OBJECTIVES: The endotoxemia associated with cardiac surgery is thought to be dominantly influenced by the use of cardiopulmonary bypass. The objectives of this study were to assess the relative contribution of cardiopulmonary bypass on endotoxemia apart from cardiac surgical access and to improve our understanding of the potential benefits of off-pump procedures. METHODS: Thirty patients undergoing coronary artery bypass grafting were followed up prospectively. The patients were divided into 2 equal groups: those who underwent bypass grafting through a sternotomy incision without cardiopulmonary bypass (off-pump group) and those who underwent bypass grafting through a sternotomy incision with cardiopulmonary bypass (CPB group). Blood sampling for endotoxin, lactate, and cardiac index measurements were performed during the following time points: (1) after sternotomy; (2) during the coronary occlusion period in the off-pump group and during aortic clamping in the CPB group; (3) after removal of the coronary occlusion sutures in the off-pump group and after removal of the aortic clamp in the CPB group; (4) 30 minutes after the completion of all distal anastomoses in the off-pump group and immediately after weaning from cardiopulmonary bypass in the CPB group; (5) 1 hour postoperatively; and (6) 12 hours postoperatively. RESULTS: Endotoxin and lactate levels were significantly (P <.05) lower in the off-pump group at all sampling time points, except after sternotomy. CONCLUSIONS: In conclusion, this study has shown that endotoxemia during coronary artery bypass surgery seems mainly to be associated with cardiopulmonary bypass procedure. The relatively lower endotoxin levels observed in off-pump surgery might contribute to improved postoperative recovery.

Cardiopulmonary Bypass↗
PubMed1986

Comparison of nitroglycerine, verapamil and nifedipine in the management of arterial pressure during coronary artery surgery.

The efficacy of nitroglycerine, verapamil and nifedipine in controlling post-sternotomy hypertension was compared in four groups of 20 patients anaesthetized with fentanyl 100 micrograms kg-1 undergoing elective coronary artery surgery. Vasodilators were started before surgery and adjusted to maintain systolic arterial pressure less than 120% of pre-infusion values, the mean (+/- SEM) requirements being: nitroglycerine (group II) 3.6 +/- 0.6 micrograms kg-1 min-1; verapamil (group III) 31.1 +/- 2.6 micrograms kg-1 min-1; nifedipine (group IV) 1.7 +/- 0.2 microgram kg-1 min-1. Systolic pressure decreased significantly by 5 min after starting infusions in groups II and III. In the control group (I: no vasodilator) arterial pressure increased significantly following skin incision and sternotomy. Pulmonary arterial and capillary wedge pressures increased significantly following sternotomy in groups I and III. Heart rate increased after sternotomy in all groups, but only reached significance in groups III and IV. There were no significant changes in cardiac index or vascular resistance, although the latter remained lower than pre-infusion values at all times in groups III and IV. The P-Q interval increased significantly in group III. It is concluded that nifedipine is a suitable alternative to nitroglycerine for the control of arterial pressure during coronary artery surgery, but verapamil is not recommended because of its negative inotropic effect and its depressant effect on A-V conduction.

Blood Pressure↗
PubMed1997

Atelectasis is a major cause of hypoxemia and shunt after cardiopulmonary bypass: an experimental study.

BACKGROUND: Respiratory failure after cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. The authors tested the hypothesis that atelectasis is an important factor responsible for the increase in intrapulmonary shunt after CPB. METHODS: Six pigs received standard CPB (bypass group). Six other pigs had the same surgery but without CPB (sternotomy group). Another six pigs were anesthetized for the same duration but without any surgery (control group). The ventilation-perfusion distribution was measured with the inert gases technique, extravascular lung water was quantified by the double-indicator distribution technique, and atelectasis was analyzed by computed tomography. RESULTS: Intrapulmonary shunt increased markedly after bypass but was unchanged over time in the control group (17.9 +/- 6.2% vs. 3.5 +/- 1.2%; P < 0.0001). Shunt also increased in the sternotomy group (10 +/- 2.6%; P < 0.01 compared with baseline) but was significantly lower than in the bypass group (P < 0.01). Extravascular lung water was not significantly altered in any group. The pigs in the bypass group showed extensive atelectasis (32.3 +/- 28.7%), which was significantly larger than in the two other groups. The pigs in the sternotomy group showed less atelectasis (4.1 +/- 1.9%) but still more (P < 0.05) than the controls (1.1 +/- 1.6%). There was good correlation between shunt and atelectasis when all data were pooled (R2 = 0.67; P < 0.0001). CONCLUSIONS: Atelectasis is produced to a much larger extent after CPB than after anesthesia alone or with sternotomy and it explains most of the marked post-CPB increase in shunt and hypoxemia. Surgery per se contributes to a lesser extent to postoperative atelectasis and gas exchange impairment.

Animals↗