Abstract: OBJECTIVE: Complete myocardial revascularization is the standard for coronary artery bypass grafting. It has been shown, however, that off-pump coronary bypass surgery (OPCAB) may reduce completeness of revascularization without affecting perioperative myocardial infarction rates. We evaluated the influence of OPCAB on major postoperative events in a large consecutive cohort of patients, with special emphasis on risk factors for perioperative myocardial infarction. METHODS: From 1995 to 2004, 5935 patients underwent isolated coronary bypass surgery; of these, 4623 (77.9%) and 1312 (22.1%) underwent on-pump coronary surgery (CABG) and OPCAB, respectively. Patients undergoing OPCAB were matched to patients undergoing CABG by propensity score; logistic regression analysis models were used to study predictors of perioperative myocardial infarction. RESULTS: In matched pairs, postoperative mortality, myocardial infarction, stroke, and atrial fibrillation were similar between groups, while reoperation for bleeding, time on ventilator and red blood cell use were lower in patients undergoing OPCAB. The number of distal anastomoses was lower in patients undergoing OPCAB (2.2+/-0.80 in OPCAB vs 2.9+/-0.86 in CABG, p<0.001), as well as complete revascularization rates (61.9% in OPCAB vs 90.0% in CABG, p<0.001). Multivariate analyses, performed on preoperative and intraoperative variables, showed that both incomplete revascularization and increasing numbers of distal anastomoses (even when controlling for completeness of revascularization) were significant predictors of perioperative myocardial infarction, while CABG/OPCAB strategy did not influence it. CONCLUSIONS: The choice of surgical technique did not influence the occurrence of major perioperative complications and of myocardial infarction, which is negatively affected by incomplete or too extensive revascularization strategies.
Abstract: OBJECTIVE: To assess the preventive effect of the antioxidant N-acetylcysteine on postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery. DESIGN: Randomized, placebo-controlled, prospective study. SETTING: University cardiology center. PATIENTS: Two hundred fifty-four consecutive patients with chronic renal insufficiency (estimated creatinine clearance < or = 60 mL/min) undergoing elective cardiac surgery. INTERVENTIONS: Patients were randomized to receive N-acetylcysteine (n = 129) or placebo (n = 125). Patients of the N-acetylcysteine group received four boluses of intravenous N-acetylcysteine (1200 mg every 12 hrs, starting immediately before cardiac surgery). MEASUREMENTS AND MAIN RESULTS: The incidence of postoperative acute renal failure (> 25% increase in serum creatinine from baseline) and the in-hospital clinical course were evaluated. Acute renal failure occurred in 46% of patients and was associated with increased in-hospital mortality (7% vs. 0.7%; p = .024). It occurred in 52% of control patients and 40% of N-acetylcysteine-treated patients (p = .06). In-hospital mortality and need for renal replacement therapy were not affected by N-acetylcysteine, but a lower percentage of N-acetylcysteine-treated patients required mechanical ventilation prolonged for > 48 hrs (3% vs. 18%; p < .001) and had an intensive care unit stay > 4 days (13% vs. 33%; p < .001). CONCLUSIONS: Intravenous administration of N-acetylcysteine does not clearly prevent postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery.
Abstract: OBJECTIVE: The aim of this study was to determine if there is a direct relationship between the duration of cardiopulmonary bypass (CPB time [CPBT]) and postoperative morbidity and mortality in patients undergoing cardiac surgery. DESIGN: Retrospective study. SETTING: Cardiac surgery unit, university hospital. PARTICIPANTS: Five thousand six patients, New York Heart Association classes 1 through 4, who underwent cardiac surgery between January 2002 and March 2008. INTERVENTIONS: All patients were subjected to CPB. MEASUREMENTS AND MAIN RESULTS: The mean CPBT was 115 minutes (median 106). One hundred thirty-one patients (2.6%) died during the same hospitalization. The postoperative median blood loss was 600 mL. Reoperations for bleeding occurred in 193 patients (3.9%), and 1,001 patients received 3 or more units of red blood cells. There were 108 patients (2.2%) with neurologic sequelae, 391 patients (7.8%) with renal complications, 37 patients (0.7%) with abdominal complications, and 184 patients (3.7%) with respiratory complications. Seventy-two patients (1.4%) had an infective complication, and 80 patients (1.6%) had a postoperative multiorgan failure. The multivariate analysis confirmed the role of CPBT, considered in 30-minute increments, as an independent risk factor for postoperative death (odds ratio [OR] = 1.57, p < 0.0001), pulmonary (OR = 1.17, p < 0.0001), renal (OR 1.31, p < 0.0001), and neurologic complications (OR = 1.28, p < 0.0001), multiorgan failure (OR = 1.21, p < 0.0001), reoperation for bleeding (OR = 1.1, p = 0.0165), and multiple blood transfusions (OR = 1.58, p < 0.0001). CONCLUSIONS: Prolonged CPB duration independently predicts postoperative morbidity and mortality after cardiac surgery.
Abstract: OBJECTIVE: Cerebrovascular accidents (CVA) are devastating complications after coronary artery bypass grafting (CABG). The reported incidence of neurological complications after conventional CABG (CCABG) is 3-6%. Off-pump coronary bypass grafting (OPCAB) has been associated in recent studies to a decreased morbidity and risk of perioperative stroke. Nevertheless, uncertainty still surrounds the relative benefits of OPCAB. We investigated whether, in our experience, OPCAB was associated with lower neurological morbidity than conventional CABG approach. METHODS: Eight thousand and two patients underwent isolated CABG at our institution between January 1998 and January 2005. OPCAB operation was performed on 1415 patients. Data were prospectively collected. A multiple logistic regression analysis was used to evaluate the influence of the two different surgical techniques on the neurological outcomes. RESULTS: Patients in the OPCAB group were significantly older (66.2 vs 63.5%, p<0.0001), had a higher incidence of renal injury (5.4 vs 2.4%, p<0.0001), and were more redo interventions (6.95 vs 1.53%, p<0.0001). The CCABG patients were more urgent at operation (5.46 vs 3.26, p=0.0007), were less hypertensive (57.6 vs 63% of the patients, p=0.0003) more diabetics (22 vs 20.6%, NS), and had an ejection fraction less than 0.40 (10.4 vs 9.6%, NS). CVA incidence was similar in both groups (Type I outcome: OPCAB=0.70% vs CCABG=0.68%, p=0.91; Type II outcome OPCAB=0.70% vs CCABG=0.83%, p=0.63). CONCLUSIONS: In our experience patients undergoing CCABG were not exposed to a greater risk of neurological adverse events when compared to OPCAB patients.
Abstract: OBJECTIVES: To assess if 2 different anesthesia strategies, high-thoracic epidural anesthesia (HTEA) plus inhalation anesthesia and total intravenous anesthesia (TIVA) with sufentanil/propofol had different influence on outcomes of coronary artery bypass graft (CABG) surgery patients. DESIGN: Retrospective comparison of outcomes between HTEA and TIVA patients using propensity score pair-wise matching of patients. SETTING: A university teaching hospital. Participants: A study of 1,473 consecutive patients undergoing elective CABG surgery; of these, 476 (32%) received HTEA combined with inhalation anesthesia, whereas 997 (68%) underwent TIVA alone. INTERVENTIONS: The patients undergoing CABG surgery were offered the epidural-inhalation anesthetic approach. MEASUREMENTS AND MAIN RESULTS: Propensity matching yielded 389 pairs of patients. Patients were well matched in preoperative and operative features. Postoperative mortality, myocardial infarction, stroke, acute renal failure rates, and intensive care unit (ICU) stay were not statistically different in HTEA and TIVA groups. On the other hand, patients treated with HTEA had shorter ventilation times (5.8 +/- 3.11 v 6.9 +/- 5.0 hours, HTEA and TIVA, respectively, p < 0.001); in addition, vasoconstrictors were more frequently used in cases of HTEA, whereas vasodilators were mainly used with TIVA both intra- and postoperatively. No neurologic complications related to the use of HTEA were observed. CONCLUSIONS: HTEA and TIVA provided similar early outcomes after CABG surgery, and there were no major differences between these 2 strategies in the average risk CABG patient populations. Although HTEA did not cause neurologic problems and yielded a significant reduction in time to extubation, a consistent benefit over standard techniques could not be shown.
Abstract: OBJECTIVES: The aim of this study, undertaken in patients who underwent mitral valve (MV) repair surgery, was to evaluate the feasibility and accuracy of 3-dimensional (3D) transthoracic (TTE) and transesophageal (TEE) echocardiography in the evaluation of MV pathology. BACKGROUND: A pre-operative assessment of MV anatomy is essential to surgical design in patients undergoing MV repair. Although 2-dimensional (2D) echocardiography provides precise information regarding MV anatomy, 3D TTE and 3D TEE could increase the understanding of MV apparatus and individual scallop identification. METHODS: One-hundred-twelve consecutive patients with severe mitral regurgitation due to MV prolapse underwent a complete 2D and 3D TTE the day before surgery and a complete 2D and 3D TEE in the operating room. Echocardiographic data obtained by the different techniques were compared with surgical inspection. RESULTS: Three-dimensional techniques were feasible in a relatively short time (3D TTE: 7 +/- 4 min; 3D TEE: 8 +/- 3 min), with good (3D TTE 55%; 3D TEE 35%) and optimal (3D TTE 21%; 3D TEE 45%) imaging quality in the majority of cases. Three-dimensional TEE allowed more accurate identification (95.6% accuracy) of all MV lesions in comparison with other techniques. Three-dimensional TTE and 2D TEE had similar accuracies (90% and 87%, respectively), whereas the accuracy of 2D TTE (77%) was significantly lower. CONCLUSIONS: Three-dimensional TTE and TEE are feasible and useful methods in identifying the location of MV prolapse. They were superior in the description of pathology in comparison with the corresponding 2D techniques and should be regarded as an important adjunct to standard 2D examinations in decisions regarding MV repair.
Abstract: BACKGROUND: Conventional on-pump coronary artery bypass grafting (CABG) is associated with a systemic inflammatory response and by an increased production of reactive oxygen species, whereas off-pump coronary artery bypass grafting (OPCAB) is thought to be accompanied by less oxidative stress. Urinary isoprostane iPF2alpha-III is a new marker reflecting oxidative stress; it has emerged as the most reliable marker of oxidative stress status in vivo. This study was designed to ascertain whether OPCAB compared with CABG represents a surgical strategy that avoids oxidative stress. To this end urinary isoprostanes and other established oxidative stress markers were measured during the first 24 hours after CABG and OPCAB. METHODS: Fifty low-risk coronary patients were randomly assigned to CABG or OPCAB. Urinary isoprostane iPF2alpha-III levels, plasma levels of free malondialdehyde, and total antioxidant status were measured before, during, and up to 24 hours after surgery. RESULTS: In OPCAB iPF2alpha-III excretion remained unchanged throughout the study. As expected, in CABG iPF2alpha-III levels significantly increased during surgery and returned at baseline 24 hours later. Free malondialdehyde behaved similarly, with no change in OPCAB and sharp increases during CABG. Conversely, total antioxidant status showed a sharp drop during CABG, followed by a slow recovery, whereas a significantly lower drop occurred in OPCAB. CONCLUSIONS: In this randomized study in low-risk coronary patients, OPCAB revealed less perioperative oxidative stress, as reflected by lack of excretion of iPF2alpha-III in urine, by lack of increase of plasma free malondialdehyde, and by lower decreases in plasma total antioxidant status.
Abstract: OBJECTIVE: To assess the feasibility of high thoracic epidural anesthesia combined with sevoflurane for off-pump coronary artery bypass surgery and to evaluate the postoperative pain control, side effects, and perioperative hemodynamics. DESIGN: Retrospective review of prospectively collected data. SETTING: A university teaching hospital. PARTICIPANTS: One hundred six consecutive patients receiving thoracic epidural combined with sevoflurane. INTERVENTION: From November 1999, the patients undergoing off-pump coronary artery bypass grafting were offered the epidural-inhalation anesthetic approach. MEASUREMENTS AND MAIN RESULTS: Insertion of the epidural catheter was successful in all but 2 patients; 1 bloody tap occurred and the dura was never punctured, although 1 patient presented with postoperative paraplegia. An emergency spinal cord nuclear magnetic resonance excluded signs of medullary compression caused by epidural or spinal hematoma. Visual analog scale scores for pain during the first 24-hour period were < 2 in all patients. Mean time to extubation was 4.6 +/- 2.9 hours. The average intensive care unit stay was 1.5 +/- 0.8 days. Incidences of perioperative myocardial infarction, myocardial ischemia, and atrial fibrillation were 2.8%, 7.5%, and 10.6%, respectively. Two patients died: 1 from multiorgan failure and the other from myocardial infarction. Heart rate, mean arterial pressure, cardiac index, and systemic vascular resistance were not affected by thoracic epidural alone. Mean arterial pressure and cardiac index decreased (p < 0.05) when general anesthesia was induced and remained stable thereafter. Neither heart rate nor systemic vascular resistance changed from baseline during operation. CONCLUSIONS: Thoracic epidural as an adjunct to general anesthesia is a feasible technique in off-pump coronary artery bypass surgery. It induces intense postoperative analgesia and does not compromise central hemodynamics.
Abstract: BACKGROUND AND AIM OF THE STUDY: Mitral valve repair has recently emerged as the treatment of choice in patients presenting with insufficiency due to valve prolapse. The study aims were to evaluate: (i) the clinical presentation in a consecutive series of patients with mitral valve prolapse undergoing surgical repair; (ii) the correlation between pre- and intraoperative echocardiographic features and surgical findings in these patients; and (iii) whether clinical and echocardiographic data may predict surgical outcome. METHODS: Between March 1997 and May 2000, 152 patients (110 men, 42 women; mean age 59+/-13 years) were recruited into the study. All patients had myxomatous mitral valve disease causing severe regurgitation and underwent systematic examination by transesophageal echocardiography (TEE) for clear delineation of the three scallops of the posterior leaflet and juxtaposed segments of the anterior leaflet. RESULTS: In 119 patients (78%) a flail valve was documented by TEE and confirmed on surgical inspection; an anterior leaflet chordal rupture was not visualized by TEE in one case. In 15 cases (10%) there was flail of the anterior leaflet, and in 105 cases (69%) flail of the posterior leaflet. A bileaflet complex prolapse without chordal rupture was found in 32 cases. On the basis of TEE evaluation, mitral valve replacement was performed electively in 10 patients (7%); the other 142 (93%) underwent mitral valve repair. Adequate repair was obtained in 93% of cases; residual mitral regurgitation (eight cases; grade 3+) and mitral stenosis (one case) were documented by intraoperative TEE, and nine patients (6%) underwent valve replacement. CONCLUSION: The majority of patients with myxomatous mitral valve prolapse and severe regurgitation undergoing valve repair have chordal rupture of the posterior mitral leaflet, a condition in which results of valve repair are excellent. TEE provides a powerful means to define the mechanisms of mitral regurgitation and to identify the suitability of patients for valvuloplasty.
Abstract: BACKGROUND: In essential hypertension, the lower limit of autoregulation of coronary flow shifts to higher perfusion and the hypertensive ventricle is at a higher than normal risk of ischemia, and less able to tolerate acute reduction of coronary perfusion pressure. Little is known about pattern of coronary flow in isolated systolic hypertension, a pathologic condition in which the elevated systolic blood pressure is associated with a lower than normal vascular compliance and normal or slightly greater than normal mean arterial pressure and vascular resistance. OBJECTIVE: To evaluate the effects of rapid normalization of blood pressure on coronary blood flow in isolated systolic hypertension. METHODS: We subjected 20 patients with isolated systolic hypertension to intraoperative hemodynamic and transesophageal echocardiographic monitoring during peripheral vascular surgery. Coronary flow velocity integrals and diameters in the left anterior descending coronary artery were evaluated under baseline conditions and after normalization of blood pressure, which occurred spontaneously during anesthesia (10 cases; group 1A) or was induced by infusion of nitrate (10 cases, group 1B). RESULTS: After normalization of systolic blood pressure integrals decreased significantly only for patients in group 1A; percentage changes of diameter were significantly greater for patients in group 1B. Therefore, coronary blood flow after normalization of systolic blood pressure increased for patients in group 1B (by 28+/-25%) and decreased for patients in group 1A (by 30+/-21%). Changes in integrals were inversely related to those in diameter (r= -0.72, P < 0.001); for patients in group 1A changes in coronary perfusion pressure and diameter were related to those of integrals (r= 0.94; P < 0.0005). CONCLUSIONS: In isolated systolic hypertension, despite there being similar changes of the systolic blood pressure, administration of nitrates caused a marked increase of coronary flow through direct effects on coronary circulation, whereas spontaneous normotension was associated with a significant reduction of coronary flow.
Abstract: A male patient suffering for exertional angina was scheduled for coronary bypass. Physical examination was unremarkable except for oropharynx classified as Mallampati II. After anesthetic induction with fentanyl 10 micrograms/kg, thiopental 5 mg/kg and muscle relaxation with succynilcoline 1 mg/kg, the patient was ventilated via a face mask. Laryngoscopy revealed a bulky mass arising from the rigth base of the tongue hiding the epiglottis and all the vocal apparatus (Cormack class 4); a failed intubation caused bleeding. Facial mask ventilation became more difficult therefore, considering the task on managing the airway, a n. 4 laryngeal mask was positioned by the senior anesthetist. Two intubation attempts failed while ventilation via laryngeal mask became more and more difficult. Surgery was therefore cancelled due to inability to airway management. The mass, biopsied by an otolaryngologist, resulted to be a lingual tonsillar hyperthrophy and therefore was not removed. The patients was re-scheduled for cardiac surgery. Maintaining spontaneous breathing during light sedation, with topical anesthesia, this patient was successfully intubated over an Olympus BF P 10 bronchoscope. The patient had an uneventful operation, was regularly extubated and was discharged on the sixth postoperative day free from airway complications. Although we followed only some of the guidelines for the management of the difficult airway: a senior anesthetist was immediately called when an anatomic alteration was evident; progressive difficulty in maintaining the airway prompted the positioning of a LMA, the restoration of the spontaneous breathing and the cancellation of the elective operation had been mandatory when a class 4 Cormack was found at laryngoscopy. This situation requires an alternative approach to intubation or with the retrograde technique or with the aid of a fiberscope both maintaining spontaneous breathing.
Abstract: It is already known that activation of the coagulation and fibrinolytic system occurs in patients undergoing cardiopulmonary bypass (CPB). We have thus studied twenty patients (10 treated with aprotinin during CPB and 10 untreated) both during the intraoperative period and during thirty days follow up. In untreated patients D-dimer levels increased 4-fold during CPB and the levels were above baseline for the whole follow up (p < 0.0001). D-dimer levels were reduced in aprotinin treated patients in comparison to untreated patients (p = 0.0172); levels then gradually increased to the values of the untreated patients over the following 24 h later and remained higher during the thirty day follow up. The behavior of haemostatic variables in the 24 h after CPB did not vary between untreated and aprotinin treated patients. In particular, five minutes after protamine sulphate administration, levels of F1 + 2 and TAT rose significantly (p = 0.0054, p = 0.0022 respectively), whereas fibrinogen significantly decreased (p < 0.0001) and PAI-1 antigen levels were reduced. Two days after CPB the concentrations of F1 + 2 and TAT lowered, whereas fibrinogen and PAI-1 antigen levels increased. On the 5th, 8th and 30th days after CPB, F1 + 2 and TAT levels remained higher than those reported at baseline in both groups of patients, whereas fibrinogen levels increased over basal levels in aprotinin treated patients only. Thus, in addition to the activation of the coagulation and fibrinolytic system occurring during the intraoperative period, in patients undergoing CPB, there are alterations of haemostatic variables up to thirty days from surgery.
Abstract: A 71-year-old woman submitted to multiple coronary artery bypass grafts suddenly developed in the third postoperatory day cardiogenic shock. Transesophageal echocardiography examination and color Doppler showed prolapse of the anterior mitral valve leaflet and detached anterolateral papillary muscle in the left atrial cavity with severe mitral valve regurgitation and increased left ventricular wall kynesis. Maximal inotropic and vasodilator support was not effective and a mechanical circulatory assistance was deemed necessary awaiting for mitral valve replacement not performed on emergency for unavailability of operatory rooms. Hemopump pump-cannula assembly was introduced through a femoral graft and the cannula was advanced in the aorta and positioned in the left ventricle across the aortic valve. Pump rate was set at the maximal speed and as an immediate result, mean arterial pressure increased and mean pulmonary pressure decreased. Global cardiac output during 190 min of assistance was 3.48 l/min at a mean arterial pressure of 81 mmHg. The Hemopump provided 3 l/min of flow with an effective left ventricle unloading. The patient subsequently underwent mitral valve replacement and her postoperative outcome was uneventful and free from complications.
Abstract: In a retrospective study, 42 patients with acute cardiac tamponade due to pericardial effusion were evaluated following cardiac surgery, and the pericardial fluid was drained by one of two alternative methods: two-dimensional echocardiographic-guided pericardiocentesis (2D-echo) or subxiphoid surgical pericardiotomy. During the first period (from 1982 to 1986), one of the two methods was chosen by the treating physicians, whereas in the second period (from 1986 to 1991), 2D-echo-guided pericardiocentesis was the treatment of choice. Percutaneous pericardiocentesis was performed using local anesthesia in 29 patients. A Tuohy needle was inserted at the left xipho-costal junction and, when fluid was obtained, 6 mL of saline solution was injected during 2D-echo contrast monitoring, and a multiple-hole, 6F, 30-cm catheter was inserted by means of a guidewire and positioned into the posterior pericardium, as near as possible to the atrioventricular groove. Complete drainage of pericardial fluid by percutaneous pericardiocentesis was obtained in 26 patients (89%). This procedure also allowed the evacuation of posterior and loculated effusions. Complications included two right ventricular punctures, which were immediately recognized by 2D-echo contrast and produced no serious consequences. Sixteen patients who underwent surgical pericardiotomy had complete evacuation of pericardial fluid without major complications (two of them suffered atrial arrhythmias during the procedure). The average amount of fluid drained, as well as the localization of the effusions, were the same for both groups. 2D-echo-guided pericardiocentesis was found to be a useful, safe, and simple technique. It can be used as an alternative treatment to subxiphoid pericardiotomy for cardiac tamponade due to postoperative pericardial effusions.
Abstract: A 65-year-old man with long-standing hypertension developed cardiogenic shock due to the onset of left ventricular outflow obstruction and severe mitral regurgitation after surgical repair for abdominal aortic aneurysm. This complication occurred in the early postoperative period and reversed immediately after treatment with intravenous verapamil.
Abstract: Although treatment of refractory atelectasis has been improved by pulmonary insufflation through FOB with balloon cuff, low pulmonary compliance and high critical opening pressure of alveoli in the atelectatic areas require a more selective approach to prevent pressure dispersion to highly compliant zones. To achieve the highest insufflation selectivity and reduce patient discomfort, we have devised a small caliber balloon-tipped catheter to easily reach even the minor branches of the bronchial tree. This result was obtained by utilizing the performed curve of the catheter distal end after withdrawing the internal stylet. The catheter was introduced through the nostrils (16 patients) or through an endotracheal tube (two patients) and advanced under fluoroscopic guidance. Reexpansion of atelectatic areas was accomplished by repeated air injections through a 60-ml syringe. No complications were observed. Complete disappearance of x-ray film evidence of atelectasis was obtained in 15 patients and partial reexpansion in 3 patients.
Abstract: Twenty patients (ten with mitral and/or aortic valve disease and ten with ischemic heart disease, all in the New York Heart Association class IV, aged between 18 and 74 yr, with cardiogenic pulmonary edema unresponsive to drug treatment) were treated with polysulphone membrane ultrafiltration (UF) in a veno-venous circuit. All patients had dyspnea, pulmonary rales, hypoxemia, tachycardia, hypotension, overhydration, radiologic evidence of engorged pulmonary vasculature, and Kerley-B lines. Systemic and pulmonary arterial pressures, cardiac output (by thermodilution), and intrapulmonary shunt fraction (Qsp/Qt) were determined and chest x-ray was obtained at the beginning and the end of UF. Average duration of the treatment was 150 +/- 28 min; UF volume averaged 3000 +/- 170 ml. UF reduced the Qsp/Qt by 58% from control condition, and did not significantly affect hemodynamic variables. Chest x-rays documented clearing of alveolar edema and venous congestion. These changes were associated with unequivocal clinical improvement and no mechanical ventilation was necessary to improve gas exchange. Short-term fluid subtraction did not result in undesired circulatory alternations. Because the ultrafiltrate composition is similar to plasmatic fluid, no modification in the plasma osmolarity was detected. In conclusion, UF may be considered an effective tool for the treatment of acute pulmonary edema refractory to drug therapy, as an alternative to mechanical ventilation, and as a remedy for excessive extravascular lung water.
Abstract: We studied in humans during total cardio-pulmonary by-pass the effects of positive alveolar pressure on systemic to pulmonary bronchial blood flow. Systemic to pulmonary bronchial blood flow is the entire bronchial blood flow to the lung and was measured as the volume of blood which accumulates in the left heart when there is no pulmonary flow. Systemic to pulmonary bronchial blood flow was vented by gravity via a cannula (18 French) introduced in the upper superior pulmonary vein and advanced into the lower most portion of the left heart. In Group A (10 patients) systemic to pulmonary bronchial blood flow was measured with alveolar pressure constant at 4.0 +/- 0.4 cm H2O for 53.5 +/- 6.2 min (range 25 to 95 min), and ranged between 0.32 and 2.76% of cardiac output (pump flow) remaining constant with time. In Group B (10 patients) systemic to pulmonary bronchial blood flow was measured for 2 periods of 20 min each with alveolar pressure equal 4.1 +/- 0.2 and 14.1 +/- 0.4 cm H2O respectively. The increase of alveolar pressure reduced systemic to pulmonary bronchial blood flow by almost 40%. The reduction of systemic to pulmonary bronchial blood flow we observed may be deleterious for the survival of the lung parenchyma particularly in some circumstances. This is the case of pulmonary embolism, when bronchial blood flow is the major source of blood to the lung parenchyma and serves to prevent pulmonary infarction, or the case of acute respiratory distress syndrome, when pulmonary flow is compromised and systemic to pulmonary bronchial blood flow increases.(ABSTRACT TRUNCATED AT 250 WORDS)
