Donor and recipient treatment with the Lazaroid U-74006F do not improve post-transplant lung function in swine

OBJECTIVE

U-74006F is the only Lazaroid which is currently in clinical use. A number of experimental studies demonstrate that Lazaroids reduce ischemia/reperfusion injury in various organ systems. We evaluated the effect of U-74006F on reperfusion injury in a large animal model of lung allo-transplantation.

METHODS

Two different treatment modalities were evaluated and compared with corresponding control groups. Unilateral left lung transplantation was performed in 21 weight-matched pigs (24-31 kg). Donor lungs were flushed with 1.51 cold (1 degrees C) LPD solution and preserved for 20 h. In group I (n = 5), donor animals were pretreated with U-74006F (10 mg/ kg i.v.) 20 min before harvest. In addition U-74006F was added to the flush solution (10 mg/l). In group III (n = 6), the Lazaroid was given to the donor before flush and to the recipient before reperfusion (3 mg/kg i.v.). Group II and IV (n = 5) served as control. One hour after reperfusion, the recipient contralateral right pulmonary artery and bronchus were ligated to assess graft function only. Extravascular lung water index (EVLWI), mean pulmonary artery pressure, cardiac output, and gas exchange were assessed during a 5 h observation period. Lipid peroxidation (TBARS) and neutrophil migration (MPO activity) were measured at the end of the assessment in lung allograft tissue.

RESULTS

A significant change of TBARS concentration was shown in group III (group III 78.7+/-4.6 pmol/g vs. group IV 120.8+/-7.2 pmol/g (P = 0.0065) normal lung tissue 41.3+/-4.2 pmol/g). MPO activity was reduced in group III 3.74+/-0.25 deltaOD/mg per min vs. group IV 4.97+/-0.26 deltaOD/mg per min (P = 0.027), normal lung tissue 1.04+/-0.27 deltaOD/mg per min). Pulmonary hemodynamics and gas exchange after reperfusion did not differ between groups. In group I and III, a tendency towards a reduced EVLWI was noted.

CONCLUSION

We conclude that combined treatment of donor and recipient with U-74006F reduces free radical mediated injury in the allograft. However, this intervention did not result in a significant reduction of post-transplant lung edema or improvement of pulmonary hemodynamics. Donor pretreatment alone did not improve lung allograft reperfusion injury. These results indicate that the benefit of U-74006F is too small to consider clinical application in lung transplantation.

Compromised blood coagulation: an in vitro comparison of hydroxyethyl starch 130/0.4 and hydroxyethyl starch 200/0.5 using thrombelastography

We compared the effects of progressive in vitro hemodilution (30% and 60%) on blood coagulation in 80 patients receiving one of two different 6% hydroxyethyl starch (HES) solutions using thrombelastography (TEG). The newly developed solution has a mean molecular weight of 130 kD and a degree of substitution, defined as the average number of hydroxyethyl groups per glucose moiety, of 0.4 (HES 130/0.4); the conventional solution has a mean molecular weight of 200 kD and a degree of substitution of 0.5 (HES 200/0.5). Both HES solutions significantly compromised blood coagulation, as seen by an increase in reaction time and coagulation time and a decrease in angle alpha, maximal amplitude, and coagulation index (all P < 0.05). There was no difference between HES 130/0.4 and HES 200/0.5 diluted blood (P > 0.05 for all TEG variables). When analyzing the intrinsic HES effect by taking hemodilution with 0.9% saline into account, progressive hemodilution with both HES solutions resulted in an increasing clot lysis (P < 0.05 after 60 min). Again, there was no difference between HES 130/0.4 and HES 200/0.5 diluted blood. We conclude that HES 130/ 0.4 and HES 200/0.5 compromise blood coagulation to the same degree.

IMPLICATIONS

Progressive in vitro hemodilution using hydroxyethyl starch (HES) compromises blood coagulation. We observed similar effects of a new HES solution with a mean molecular weight of 130 kD and a degree of substitution of 0.4 (HES 130/0.4), compared with the conventional HES 200/0.5.

Perioperative reliability of an on-site prothrombin time assay under different haemostatic conditions

Perioperative use of laboratory coagulation assays is limited by the delay in obtaining results. The management of haemostasis during major surgical procedures requires rapid and accurate measurement of the prevailing coagulation status. In this prospective study, we have evaluated the reliability of on-site prothrombin time assessed by the portable coagulation monitor CoaguChek-Plus compared with standard laboratory assays during elective non-cardiac surgery. Sixty-two patients were assigned to one of three groups: group A = normal preoperative coagulation where minor intraoperative blood loss is expected; group B = normal preoperative coagulation where major intraoperative blood loss is expected; and group C = preoperative anticoagulation and minor intraoperative blood loss expected. On-site prothrombin time and laboratory prothrombin time showed poor correlation in group A (r2 = 0.24; bias (2 SD) 1.80 (3.34) S) and group B (r2 = 0.30; 1.43 (3.12) S). The correlation in group C was better (r2 = 0.71; 1.41 (1.92) S). We conclude that prothrombin time measured with the CoaguCheck-Plus monitor did not appear to be suitable for the management of haemostasis.

Substantial changes in arterial blood gases during thoracoscopic surgery can be missed by conventional intermittent laboratory blood gas analyses

Substantial and clinically relevant changes in arterial blood gases are likely to occur during thoracoscopic surgery with one-lung ventilation (OLV). We hypothesized that they may be missed when using the conventional intermittent blood gas sampling practice. Therefore, during 30 thoracoscopic procedures with OLV, the sampling intervals between consecutive intermittent laboratory blood gas analyses (BGA) were evaluated with respect to changes of PaO2, PaCO2, and pHa ([H+]) using a continuous intraarterial blood gas monitoring system. Frequency and timing of BGA were based on the clinical judgment of 16 experienced anesthesiologists who were blinded to the continuously measured values. Extreme fluctuations of PaO2 (37-625 mm Hg), PaCO2 (27-56 mm Hg), and pHa (7.24-7.51) were observed by continuous blood gas monitoring. During 63% of all sampling intervals, PaO2 decreased >20% compared with the preceding BGA value, which remained undetected by intermittent analysis. In 10 patients with a continuously measured minimal PaO2 value < or = 60 mm Hg, the preceding BGA overestimated this minimal PaO2 by > 47%. Correspondingly, PaCO2 increases of > 10% were observed in 35% of all sampling intervals, and [H+] increases of > 10% were observed in 24% of all sampling intervals. Because these blood gas changes were not reliably detected by using noninvasive monitoring and their magnitude is not predictable during OLV, intermittent BGA with short sampling intervals is warranted. In critical cases, continuous blood gas monitoring may be helpful.

IMPLICATIONS

The magnitude of blood gas changes during thoracoscopic surgery with one-lung ventilation is not predictable and not reliably detected by noninvasive monitoring. Using a continuous intraarterial blood gas monitoring device, we demonstrated that intermittent laboratory blood gas analysis with short sampling intervals is warranted to detect arterial hypoxemia.

Prospective, randomized comparison of extrapleural versus epidural analgesia for postthoracotomy pain

BACKGROUND

Thoracic epidural analgesia is considered the method of choice for postthoracotomy analgesia, but it is not suitable for every patient and is associated with some risks and side effects. We therefore evaluated the effects of an extrapleural intercostal analgesia as an alternative to thoracic epidural analgesia.

METHODS

In a prospective, randomized study, pain control, recovery of ventilatory function, and pulmonary complications were analyzed in patients undergoing elective lobectomy or bilobectomy. Two groups of 15 patients each were compared: one received a continuous extrapleural intercostal nerve blockade (T3 through T6) with bupivacaine through an indwelling catheter, the other was administered a combination of local anesthetics (bupivacaine) and opioid analgesics (fentanyl) through a thoracic epidural catheter.

RESULTS

Both techniques were safe and highly effective in terms of pain relief and recovery of postoperative pulmonary function. However, minor differences were observed that, together with practical benefits, would favor extrapleural intercostal analgesia.

CONCLUSIONS

These results led us to suggest that extrapleural intercostal analgesia might be a valuable alternative to thoracic epidural analgesia for pain control after thoracotomy and should particularly be considered in patients who do not qualify for thoracic epidural analgesia.

The effect of potato starch derived and corn starch derived hydroxyethyl starch on in vitro blood coagulation

We have compared the effects of progressive in vitro haemodilution (30% and 60%) with potato starch derived hydroxyethyl starch and corn starch derived hydroxyethyl starch on blood coagulation in 80 patients using thrombelastography. Both solutions significantly compromised blood coagulation as evidenced by an increase in coagulation time and decrease in angle alpha, maximum amplitude and coagulation index (p < 0.05). Blood coagulation was more compromised during haemodilution with potato starch derived hydroxyethyl starch as compared with corn starch derived hydroxyethyl starch (p < 0.05). When taking the effect of haemodilution with 0.9% saline into account, haemodilution with both hydroxyethyl starch solutions also augmented clot lysis (p < 0.05), with potato starch derived hydroxyethyl starch having a greater effect than corn starch derived hydroxyethyl starch (p < 0.05). We conclude that potato starch derived hydroxyethyl starch compromises in vitro blood coagulation more than corn starch derived hydroxyethyl starch.

Effect of soluble complement receptor type 1 on reperfusion edema and neutrophil migration after lung allotransplantation in swine

OBJECTIVE

Soluble complement receptor type 1 inhibits complement activation by blocking C3 and C5 convertases of the classical and alternative pathways. We evaluated the effect of soluble complement receptor type 1 on lung allograft reperfusion injury.

METHODS

Left lung transplantation was performed in 13 weight-matched pigs (25 to 31 kg) after prolonged preservation (20 hours at 1 degree C). One hour after reperfusion the recipient contralateral right lung was excluded to assess graft function only. Complement activity and C3a levels were measured after reperfusion and at the end of the assessment. Extravascular lung water index, intrathoracic blood volume, and cardiac output were assessed during a 5-hour observation period. Gas exchange and hemodynamics were monitored. At the end of the 5-hour assessment period, myeloperoxidase assay and bronchoalveolar lavage were performed to assess neutrophil migration, and C5b-9 (membrane attack complex) deposits in the allograft were detected by immunohistochemistry. Two groups were studied. In group II (n = 6) recipient animals were treated with soluble complement receptor type 1 (15 mg/kg) 15 minutes before reperfusion. Group I (n = 7) served as the control group.

RESULTS

Serum complement activity was completely inhibited in group II. In contrast to group I, C5b-9 complexes were not detected in group II allograft tissue samples. C3a was reduced to normal levels in group II (p = 0.00005). Extravascular lung water index was higher in group I animals throughout the assessment period (p = 0.035). No significant difference in allograft myeloperoxidase activity (p = 0.10) and polymorphonuclear leukocyte count of the bronchoalveolar lavage fluid (p = 0.057) was detected.

CONCLUSION

Inhibition of the complement system by soluble complement receptor type 1 blocks local complement activation in the allograft and reduces posttransplantation reperfusion edema but does not improve hemodynamic parameters.

Whole-lung lavage in alveolar proteinosis by a modified lavage technique

Whole-lung lavage is the only efficient treatment in pulmonary alveolar proteinosis. A 36-year-old woman with severe pulmonary alveolar proteinosis confirmed by video-assisted thoracoscopic lung biopsies underwent repetitive whole-lung lavages without improvement. A modified technique consisting of manual ventilation between instillation and aspiration of half the amount of saline used for conventional lavage was applied. Impressive clinical and functional improvement occurred and persisted for 1 year. We believe that the amelioration can be attributed to the technique described above.

Effect of a short period of warm ischemia after cold preservation on reperfusion injury in lung allotransplantation

OBJECTIVE

A short period of warm ischemia during lung allograft implantation is inevitable. We studied the effect of 2 h of warm ischemia before implantation after 18 h of cold preservation on reperfusion edema and pulmonary hemodynamics in a large animal model.

METHODS

Left lung transplantation was performed in ten weight-matched pigs (25-31 kg). Donor lungs were flushed with 1.5 l cold (1 degree C) LPD solution and preserved for 20 h. In Group I (n = 5) the grafts were preserved for 20 h at 1 degree C and topically cooled with ice slush during implantation until reperfusion. In Group II (n = 5) lungs were stored at 1 degree C for 18 h followed by 2 h preservation at room temperature (20 degrees C). Topical cooling was not used during implantation. At 1 h after reperfusion the recipient contralateral right pulmonary artery and bronchus were ligated to assess graft function only. Extravascular lung water index (EVLWI), intrathoracic blood volume (ITBV), mean pulmonary artery pressure (PAP) and cardiac output (CO) were assessed during a 4 h observation period. Quantitative myeloperoxidase (MPO) activity and thiobarbituric acid-reactive substance (TBARS) levels as an indicator for lipid peroxidation were determined in allograft tissue samples taken 5 h after reperfusion.

RESULTS

In Group II a tendency to improved pulmonary vascular resistance and cardiac output was noted. Surprisingly, lung edema, assessed by EVLWI, did not increase in animals with warm ischemia. Even a tendency to a reduced EVLWI was noted. However, differences between groups did not reach statistical significance. Gas exchange did not differ statistically significant between groups.

CONCLUSION

Our results indicate that a short period of warm ischemia before reperfusion does not lead to increased pulmonary edema. In animals with a short period of warm ischemia before reperfusion, even a tendency to reduced posttransplant lung reperfusion injury was noted. In this model, topical graft cooling during lung implantation did not improve posttransplant graft function.

Effect of lung volume reduction surgery on pulmonary hemodynamics in severe pulmonary emphysema

OBJECTIVE

The presence of pulmonary hypertension in severe pulmonary emphysema has been considered a relative contraindication to lung volume reduction surgery (LVRS). There was concern that resection of lung tissue might further increase pulmonary artery pressure. To address this point, the prevalence of pulmonary hypertension in candidates for LVRS was investigated. The changes in pulmonary artery pressures after bilateral videoassisted thoracoscopic resection was studied in patients with homo- and heterogeneously destroyed emphysematous lungs.

DESIGN

The pulmonary arterial pressures by right heart catheterization were prospectively assessed, before and 6 months after LVRS in 21 consecutive patients (15 males, six females, mean (+/- S.E.) age: 62 +/- 1.9, range 42-74 years). All were former smokers and three had ZZ-AT1 deficiency. The inclusion criteria were: (a) severe bronchial obstruction (FEV1 < 35% predicted); (b) pulmonary hyperinflation (RV/TLC > 0.60); and (c) absence of hypercapnia (PaCO2 < 50 mmHg).

RESULTS

The FEV1 had increased from 28 +/- 2% to 35 +/- 3% of the predicted value (P < 0.05) 6 months after surgery. The RV/TLC had declined from 0.65 +/- 0.02 to 0.55 +/- 0.02; PaO2 increased (66 +/- 1 versus 71 +/- 2 mmHg, P = 0.04), PaCO2 (38 +/- 2 versus 36 +/- 1 mmHg, P = 0.26) did not change. The pulmonary artery mean pressure (PAPmean) remained unchanged (18 +/- 1 versus 19 +/- 1 mmHg, P = 0.26). In six patients PAPmean was > or = 20 mmHg (up to 24 mmHg) preoperatively. After 6 months, six patients had a PAPmean > or = 20 mmHg (up to 31 mmHg).

CONCLUSIONS

In patients with severe emphysema who are candidates for LVRS (but have only mild to moderate hypoxemia and a PaCO2 < 50 mmHg) we found no relevant pulmonary hypertension and pulmonary artery pressure did not change significantly after surgery. Therefore, routine right heart catheterization is not mandatory for preoperative evaluation.

Assessment of pulmonary mechanics in mechanical ventilation: effects of imprecise breath detection, phase shift and noise

OBJECTIVE

In mechanical ventilation, the assessment of pulmonary mechanics, mainly of total compliance (Crs), total resistance (Rrs), and intrinsic positive end-expiratory pressure (PEEPint), is clinically important. By using airway pressure (Paw) and flow (V'aw), the least squares fit (LSF) method allows the continuous calculation of these parameters. The objective of this work was to study the influence of imprecise breath detection, phase shift between airway pressure and flow signals, and noise on the determination of Crs, Rrs, and PEEPint.

METHODS

Paw and V'aw were mathematically simulated as well as recorded in mechanically ventilated patients. Crs, Rrs, and PEEPint were computed off-line using the LSF method. The boundaries of the breath data window and the phase relationship between Paw and V'aw signals were manipulated and noise was superimposed.

RESULTS

Both simulated and patient data gave similar results. Crs and Rrs were not sensitive to imprecise breath detection. If the first portion of the breath was missed, the mean relative error on PEEPint was 20% or 53% when the exact beginning of inspiration was missed by 0.1 or 0.3 sec, respectively. Paw lag of 66 ms with respect to V'aw yielded a relative error of -15 +/- 4% (mean +/- SD) for Rrs, -5 +/- 2% for Crs, and +13 +/- 16% for PEEPint. Paw lead of 66 ms with respect to V'aw yielded a relative error of +5 +/- 4% for Rrs, +7 +/- 3% for Crs, and +14 +/- 18% for PEEPint. Noise had very little impact on the accuracy of Crs, Rrs, and PEEPint.

CONCLUSIONS

We conclude that the LSF method allows the assessment of Crs, Rrs, and PEEPint even with high levels of noise in patients with normal lungs provided that Paw and V'aw signals are precisely synchronised and a reliable breath detection algorithm is used.

Accidental pleural puncture by a thoracic epidural catheter

We report the occurrence of an accidental pleural puncture by an epidural catheter that happened during the attempted induction of thoracic epidural anaesthesia using a paramedian approach in an awake patient. The incorrect placement of the catheter was recognised while the patient was undergoing thoracoscopic surgery. The possibility of accidental pleural puncture during attempted thoracic epidural catheter placement by either the paramedian or the midline approach should be borne in mind. A misplaced catheter may injure lung tissue and result in a potentially dangerous intra-operative tension pneumothorax.

Cerebral 6-[18F]fluoro-L-DOPA uptake in rhesus monkey: pharmacological influence of aromatic amino acid decarboxylase (AAAD) and catechol-O-methyltransferase (COMT) inhibition

FDOPA/PET scans were performed in one rhesus monkey to study the influence of three catechol-O-methyltransferase (COMT) inhibitors (CGP 28014, OR-611 and Ro 40-7592) on FDOPA pharmacokinetics. COMT inhibitors were administered in combination with carbidopa, a peripherally acting inhibitor of the aromatic amino acid decarboxylase (AAAD). FDOPA was administered intravenously and its metabolic fate in plasma was determined using an HPLC system with an on-line gamma-gamma coincidence detector. Cerebral tracer uptake was assessed in the striatum and in a non-dopaminergic brain region (occipital cortex). In the periphery, the pharmacokinetic efficiency of FDOPA was increased due to the combined inhibition of COMT and AAAD activity. All three COMT inhibitors reduced the FDOPA methylation rate constant in plasma, with complete suppression obtained in the case of Ro 40-7592. In the brain, specific 18F radioactivity (striatal minus brain reference radioactivity) increased as a result of the increase in FDOPA plasma availability following the administration of COMT and AAAD inhibitors. We established a significant linear correlation between striatal radioactivity and FDOPA plasma levels (r = 0.924 +/- 0.048, P < 0.0001 for total striatal and r = 0.948 +/- 0.054, P < 0.0001 for specific striatal radioactivity). Using plasma FDOPA radioactivity as input, we found that the striatal FDOPA uptake rate constant KiFD was not changed by any of the inhibitors. Thus, the enhancement of striatal radioactivity after application of enzyme inhibitors is a consequence of the increase in plasma FDOPA that becomes available for conversion to fluorodopamine in the striatal dopaminergic nerve terminals. By contrast, using the radioactivity in a non-dopaminergic region (cortex) as input, we found that the striatal FDOPA uptake rate constant Ki(ref) was significantly (P < 0.0001) increased following pretreatment with COMT inhibitors. Our analysis demonstrated that Ki(ref) and the 3-OMFD contribution to the cerebral radioactivity were inversely correlated.

Coronary artery disease in patients undergoing lung volume reduction surgery for emphysema

OBJECTIVES

Most patients with severe pulmonary emphysema referred for lung volume reduction surgery (LVRS) have a long-standing history of cigarette smoking. Coronary artery disease (CAD) predisposes to perioperative cardiac complications. Since symptoms and signs of myocardial ischemia are often absent in patients with severe ventilatory impairment even during exercise, we investigated the prevalence of CAD in candidates for LVRS by angiography.

DESIGN

We prospectively studied the prevalence of CAD by angiography and assessed the CAD risk factor profile in 41 candidates for LVRS (26 men, 15 women; mean age, 66+/-6.8 years; range, 52 to 76 years), who had no current symptoms or a history of myocardial ischemia.

RESULTS

In six patients (15%), asymptomatic but significant coronary lesions (> 70% stenosis) were detected. In five patients, these findings altered the clinical management. Patients with CAD had significant higher cholesterol levels, tended to have smoked more, and had more often additional vascular risk factors.

CONCLUSIONS

We found a high prevalence of angiographically significant but clinically silent CAD in this particular population of heavy smokers with advanced emphysema.

Accuracy and clinical performance of a continuous intra-arterial blood-gas monitoring system during thoracoscopic surgery

Accuracy and performance of the only currently available intra-arterial blood-gas monitoring system (Paratrend 7, PT7) were assessed in 23 patients during thoracoscopic surgery using one-lung ventilation. Over a wide range of values for arterial PO2 (6.1-61.1 kPa), PCO2 (4.1-9.5 kPa) and pH (7.19-7.50), 138 arterial blood-gas values obtained by PT7 were compared with corresponding in vitro laboratory blood-gas measurements. We found good clinical performance with the PT7 and good agreement between PT7 values and in vitro measurements for arterial PO2 (bias (1.96 SD) = 0.38 (9.52) kPa), PCO2 (0.31 (0.76) kPa) and pH (-0.017 (0.065)). Also, the bias for sequential changes between two, consecutive times was not significantly different from the ideal value of 0. We conclude that the PT7 is helpful in monitoring patients during thoracoscopy.

Thoracoscopic bilateral lung volume reduction for diffuse pulmonary emphysema

OBJECTIVE

In a prospective study, we investigated the functional results, complications and survival of bilateral video-assisted thoracoscopic (VAT) lung volume reduction (LVR) in a selected group of patients with severe, nonbullous pulmonary emphysema. From January 1994 to September 1996, 42 of 143 candidates (13 female, 29 male, 42-78 years) were operated. They were short of breath on minimal exertion due to severe airflow obstruction and hyperinflation (FEV1 < 30%) pred., TLC > 130% pred., RV > 200% pred.).

METHODS

LVR was performed bilaterally by VAT using endoscopic staplers without buttressing the staple lines. Pulmonary function test (PFT), MRC dyspnea score and 12 min walking distance were assessed preoperatively, at 3, 6 and 12 months. In addition lung function was measured at hospital discharge.

RESULTS

The patients reported a marked relief of dyspnea, which persisted at all follow-up visits (P<0.001). FEV1 increased from 0.80 +/- 0.24 (L) to 1.14 +/- 0.41 (L) postoperatively, a 43% gain (P < 0.001). A relevant increase of FEV1 persisted for at least 1 year. The residual volume to total lung capacity ratio decreased from 0.64 to 0.56 at hospital discharge. The mean 12 min walking distance increased from 500 +/- 195 (m) to 770 +/- 222 (m) after 1 year (P < 0.001). The mean hospital stay was 13 +/- 5.5 days (median 12.0), drainage time was 9 +/- 4.3 (median 8.0) days. There was no 30 day mortality. Three patients died between 2 and 15 months postoperatively by non surgery related reasons. One patient underwent lung transplantation 5 months after surgical lung volume reduction.

CONCLUSIONS

In a selected group of patients with severe, nonbullous pulmonary emphysema, bilateral LVR by VAT results in instantaneous postoperative improvement in pulmonary function and dyspnea. These favorable effects, including an amelioriation in exercise performance, lasted for at least 1 year.

Effect of progressive haemodilution with hydroxyethyl starch, gelatin and albumin on blood coagulation

We have compared the effects of progressive (30% and 60%) in vitro haemodilution with hydroxyethyl starch (HES), gelatin (GEL) and albumin (ALB) with haemodilution using 0.9% saline in 96 patients by thrombelastography. Haemodilution with HES, GEL and ALB significantly (P < 0.05) compromised coagulation time (k), angle alpha and maximal amplitude (MA), with HES having the most negative effect at 30% and 60% haemodilution (P < 0.05). Haemodilution with saline significantly affected all variables of blood coagulation and clot lysis measured by thrombelastography, resulting in an increased coagulability at 30% haemodilution. To specifically assess the intrinsic effect of plasma expander molecules on blood coagulation and clot lysis, we analysed the difference between saline diluted blood (same degree of haemodilution) and plasma expander diluted blood. Prolongation of reaction time (r) was found for HES at 30% and 60% haemodilution and for ALB at 60% haemodilution and an increase in clot lysis by HES, GEL and ALB became evident. We conclude that HES, GEL and ALB compromised blood coagulation, while the maximum effect was found with HES.

Haemodynamic effects of pneumoperitoneum in elderly patients with an increased cardiac risk

We studied the haemodynamic changes induced by pneumoperitoneum (PP) in elderly patients with increased cardiac risk (ASA class III; n = 10; age 72.3 +/- 8.8 years, mean +/- SD, P < 0.05; group 2) and compared the results with patients at normal risk (ASA class I, II; n = 12; age 55.6 +/- 11.8 years; group 1). Thermodilution measurements were performed after induction of general anaesthesia (T1), after onset of PP (T2, intraabdominal pressure 14 mmHg) and after additional 15 degrees head-up tilt (T3). In both groups PP, as compared with T1, induced a significant increase in mean arterial pressure (MAP, mmHg, group 1: 77 +/- 14 to 96 +/- 18, P < 0.05/group 2: 75 +/- 10 to 102 +/- 18, P < 0.01), mean pulmonary artery pressure (MPAP, mmHg: 15 +/- 5 to 22 +/- 4, P < 0.01/18 +/- 3 to 25 +/- 5, P < 0.01), central venous pressure (CVP, mmHg: 7 +/- 2 to 15 +/- 3, P < 0.01/7 +/- 2 to 12 +/- 2, P < 0.01), pulmonary capillary wedge pressure (PCWP, mmHg: 9 +/- 4 to 16.3, P < 0.01/8 +/- 2 to 15 +/- 6, P < 0.01) and in systemic vascular resistance (SVR, dynes s cm-5: 1415 +/- 375 to 1873 +/- 412, P < 0.01/ 1502 +/- 360 to 2067 +/- 647, P < 0.01). Cardiac index (CI, L min-1 m-2: 2.3 +/- 0.3 to 1.9 +/- 0.3, P < 0.05/2.2 +/- 0.4 to 2.2 +/- 0.5 P = 0.76) and oxygen delivery index (DO2I, mL min-1 m-2: 388 +/- 54 to 324 +/- 61, P < 0.05/358 +/- 69 to 353 +/- 82, P = 0.77) decreased in group 1 but not in group 2. Heart rate, stroke Index, pulmonary vascular resistance, arteriovenous oxygen content difference and oxygen consumption index were unchanged. After head-up tilt MAP (mmHg, 92 +/- 15, P < 0.05/ 101 +/- 17, P < 0.01), MPAP (mmHg, 20 +/- 3, P < 0.01/22 +/- 4, P < 0.05), CVP (mmHg, 12 +/- 2, P < 0.01/10 +/- 2, P < 0.01) and PCWP (mmHg, 12 +/- 3, P < 0.05/12 +/- 5, P < 0.05) remained elevated compared with T1 in both groups, SVR (dynes s cm-5, 1575 +/- 372, P = 0.13/1793 +/- 528, P < 0.01) in group 2 only. No complications occurred. The results indicate that PP is associated with significant but relatively benign haemodynamic changes. Anaesthesia for laparoscopic cholecystectomy may be performed safely also in elderly ASA class III patients with increased cardiac risk. An adequate haemodynamic monitoring is recommended.

Video-assisted thoracoscopic volume reduction surgery in patients with diffuse pulmonary emphysema: gas exchange and anesthesiological management

Arterial blood gases were studied prospectively using continuous intraarterial blood gas monitoring during thoracoscopic volume reduction surgery (VRS) in 24 patients with advanced diffuse pulmonary emphysema. Additionally, the early postoperative course (48 h) of arterial blood gases was studied retrospectively. Twenty-six operations were performed using a combination of thoracic epidural and general anesthesia with left-sided double-lumen intubation for one-lung ventilation (OLV). Arterial blood gases were determined awake, during two-lung ventilation prior to surgery, during OLV (extreme values), and after tracheal extubation. Additionally, the extremes during the whole procedure were determined: avoiding excessive peak inspiratory pressures (26.4 +/- 7.0 cm H2O), minimum PaO2 was 77 +/- 39 mm Hg (mean +/- SD), maximum PaCO2 65 +/- 14 mm Hg (P < 0.0001 versus preoperative values), and minimum pHa 7.22 +/- 0.08 (P < 0.0001). One tension pneumothorax occurred during OLV. Immediate postoperative extubation was performed in 25 of 26 cases, reintubation was necessary in two cases. One patient with coronary artery disease died 36 h after surgery. Hypercapnia (maximum PaCO2 49 +/- 8 mm Hg, minimum pHa 7.37 +/- 0.04, P < 0.01) was still observed 48 h after surgery. These results demonstrate that adequate oxygenation can be preserved during OLV for VRS, but CO2 elimination is impaired. However, intraoperative hypercapnia and immediate postoperative tracheal extubation are well tolerated.

Effects of intravenous and oral clonidine on hemodynamic and plasma-catecholamine response due to endotracheal intubation

STUDY OBJECTIVE

To investigate the effects of intravenous (IV) versus oral clonidine on alterations of heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), and plasma-catecholamines due to endotracheal intubation.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

University hospital surgery operating room.

PATIENTS

33 ASA physical status I patients were randomly assigned to either receive clonidine 3 micrograms/kg IV immediately prior to anesthesia induction, clonidine 4 micrograms/kg orally 90 minutes prior to anesthesia induction, or placebo.

INTERVENTIONS

Insertion of a 14 G cannula in a large cubital vein for the determination of plasma-catecholamines using local anesthesia. Insertion of a radial artery catheter for measuring blood pressure (BP) using local anesthesia. Transthoracic echocardiography determined CO.

MEASUREMENTS AND MAIN RESULTS

Heart rate, MAP, CO, and plasma-catecholamine concentrations were measured. Measurements were performed prior to induction, during intubation, and 10 minutes after intubation. During endotracheal intubation, MAP was significantly lower in the IV clonidine group compared with the placebo and the oral clonidine groups. Cardiac output was significantly lower in the IV clonidine group only. In contrast to the placebo group, norepinephrine plasma concentrations did not increase in either clonidine group. Significant alterations of epinephrine plasma concentrations due to intubation were not observed in either group. Hemodynamics after intubation were not impaired by clonidine treatment.

CONCLUSIONS

In conclusion, IV clonidine reduced stress response to endotracheal intubation compared with placebo. Oral clonidine at the dose used was less effective in blunting hemodynamic stress response than IV clonidine.

Bilateral volume reduction surgery for diffuse pulmonary emphysema by video-assisted thoracoscopy

We prospectively studied the surgical aspects, functional results, and complications of video-assisted bilateral thoracoscopic volume reduction surgery in patients with severe diffuse pulmonary emphysema.

METHODS

Fifteen men and five women with a mean age of 64 years (range 42 to 78 years) whose daily activity was substantially impaired by severe airflow obstruction and hyperinflation underwent thoracoscopic volume reduction surgery. The prospective preoperative assessment and postoperative assessment at 3 months included (1) pulmonary function studies, (2) grading of dyspnea, and (3) exercise performance; pulmonary function tests were also performed immediately before discharge from the hospital.

RESULTS

There was no perioperative mortality. All patients left the hospital after a median stay of 15 days (6 to 27 days). Only seven patients had a prolonged chest tube drainage time (>7 days). At 3 months the mean (+/- standard deviation) forced expiratory volume in 1 second had improved by 42% (+/-3.8%), from 0.80 L (+/-0.23) to 1.09 L (+/-0.28) (p < 0.001); residual volume had decreased from 5.8 L (+/-1.5) to 4.4 L (+/-1.0) (p < 0.001). Shortly before discharge the forced expiratory volume in 1 second was already 1.10 L (+/-0.26). The median 12-minute walking distance increased from 495 m (35 to 790 m) to 688 m (175 to 1035 m) (p < 0.001) and the mean maximal oxygen consumption from 10 ml/kg per minute (+/-2.5) to 13 ml/kg per minute (+/-2.3) (p < 0.0005). The patients reported a substantial relief of dyspnea with a mean decrease in the Medical Research Council score from 3.4 to 1.8.

Hemodilution tolerance in elderly patients without known cardiac disease

Hemodilution tolerance is not well defined in elderly patients. In 20 patients older than 65 yr and free from known cardiovascular disease, hemodynamic variables, ST segment deviation, and O2 consumption were determined prior to and after 6 and after 12 mL/kg isovolemic exchange of blood for 6% hydroxyethyl starch. The mean age of the patients was 76 +/- 2 yr (mean +/- SEM, range 66-88 yr). During hemodilution, hemoglobin decreased from 11.6 +/- 0.4 to 8.8 +/- 0.3 g/dL (P < 0.05). With stable filling pressures, cardiac index increased from 2.02 +/- 0.11 to 2.19 +/- 0.10 L.min-1.m-2 (P < 0.05) while systemic vascular resistance decreased from 1796 +/- 136 to 1568 +/- 126 dynes.s.cm-5 (P < 0.05) and O2 extraction increased from 28.0% +/- 0.9% to 33.0% +/- 0.8% (P < 0.05) resulting in a stable O2 consumption during hemodilution. No alterations in ST segments were observed in lead II during hemodilution. In lead V5, ST segment deviation became slightly less negative during hemodilution from -0.03 +/- 0.01 to -0.02 +/- 0.01 mV (P < 0.05). The moderate decrease in hemoglobin was fully compensated by both an increase in cardiac index and in O2 extraction. Electrocardiographic signs of myocardial ischemia were not observed in this population. In conclusion, isovolemic hemodilution to a hemoglobin value of 8.8 +/- 0.3 g/dL is well tolerated in elderly patients free from known cardiac disease at the ages of 65-88 yr.

Prospective study of the value of transbronchial lung biopsy after lung transplantation

Transbronchial lung biopsy (TBB) has become the gold standard for the diagnosis of acute rejection and cytomegalovirus (CMV) pneumonia in lung transplant recipients. The aim of this study was to assess the value of regular surveillance TBB in stable asymptomatic patients and to establish the role of TBB as a follow-up procedure 1 month after a previous pathological biopsy result. We prospectively evaluated 76 TBBs performed in 17 lung transplant recipients. A definite pathological results was found in 14 of 15 TBBs performed for clinical indications: CMV pneumonia (5), acute rejection grade > or = A2 according to the criteria of the International Society for Heart and Lung Transplantation (ISHLT) (4), bronchiolitis obliterans (3), and desquamative interstitial pneumonitis (2). Fifteen of 45 surveillance TBBs performed in asymptomatic patients revealed significant abnormalities. Ten episodes of acute rejection ISHLT grade > or = A2 and three episodes of CMV pneumonia detected by TBB had direct therapeutic consequences. Nine of 16 follow-up TBBs performed 1 month after a pathological biopsy result again showed relevant pathological findings. With the exception of one severe haemorrhage, no life-threatening complications occurred. Our results suggest that transbronchial lung biopsies performed on a regular basis after lung transplantation are important for the detection of asymptomatic and/or persistent acute rejection or injection. In the long-term, this strategy might be the most effective tool in reducing the incidence of bronchiolitis obliterans, which is still the main obstacle for further improvement of long-term survival after lung transplantation.

Positron emission tomography in drug evaluation: influence of three different catechol-O-methyltransferase inhibitors on metabolism of [NCA] 6-[18F]fluoro-L-dopa in rhesus monkey

We compared the influence of three different catechol-O-methyltransferase (COMT) inhibitors (CGP 28014, OR-611 and Ro 40-7592) on the metabolism of no-carrier-added (NCA) 6-[18F]fluoro-L-dopa (6-FDOPA) in one Rhesus monkey. All three COMT inhibitors improved 6-FDOPA availability in plasma, increased the specific uptake in the brain and thus improved 6-FDOPA uptake measurements using positron emission tomography (PET). Best results were obtained with Ro 40-7592.

[Isolated lung transplantation--evaluation of patients and initial results]

Between November 1992 and May 1994 we performed 10 single and 5 double lung transplants in patients with end-stage lung diseases due to lymphangioleiomyomatosis (4), cystic fibrosis (3), pulmonary hypertension (3), pulmonary fibrosis (3) and chronic obstructive lung disease (2). In the 13 patients (87%) surviving for median 245 (19-567) days, FEV1 improved from median 640 ml to 1410 ml and the 12-minute walk distance from median 315 to 1100 meters. 10 patients (77%) enjoy a good or even excellent quality of life. 2 patients died 11 and 62 days postoperatively, due to multi-organ failure and invasive pulmonary aspergillosis respectively. The main postoperative problems are fungal and cytomegalovirus infections and chronic rejection in the form of bronchiolitis obliterans. In Switzerland as elsewhere, lung transplantation has become an established modality for the management of end-stage diseases of the lung and pulmonary circulation.

[Isolated lung transplantation]

Over the last 10 years, single and bilateral lung transplantation has developed from an experimental technique to a valid therapy for patients with end-stage pulmonary or pulmonary-vascular disease. The main reasons for this progress are better defined selection criteria, improved operative technique and organ preservation, optimized peri- and postoperative management and more precise immunosuppressive and antiinfective therapy. Since 1983 more than 3000 lung transplantations have been performed worldwide with a 1- and 3-year survival rate of 70-90% and 60-70% respectively. In Switzerland 41 lung transplantations have been performed since 1992 with a 1-year survival rate of more than 80%. Indications, technique, treatment and results are discussed.

[Risk assessment and patient information before anesthesia]

In order to determine the risk of anesthesia the anesthesiologist has to assess both the physical and the psychological status of the patient. The essential basis of any preoperative medical evaluation are the history and complete physical examination of the patient. Few laboratory screening tests and, in case of pathological findings, specific diagnostic procedures will ensue. If possible, preoperative therapies must be considered in order to reduce the risk resulting from concomitant diseases. However, apart from the patients diseases, both the risks of the anesthetic and surgical procedures contribute to the overall perioperative risk. On the basis of the preoperative evaluation, the anesthesiologist determines the methods of anesthesia to be applied. He also informs the patient about the planned anesthesia, the sequence of further measures, the risk of anesthesia, and accompanying risks. The family doctor can help to facilitate the preoperative assessment by performing certain examinations himself and by providing the anesthesiologist with relevant informations. By giving a piece of advice to the patient he can help to prepare him for anesthesia and to reduce fear and apprehensiveness.

[Prognostic importance of early recorded somatosensory evoked potentials in patients not neurologically assessable after craniocerebral trauma]

By stimulation of the median nerve at the wrist we recorded the somatosensory evoked potentials (SEP) at several points between the midpoint of the clavicle and the scalp, overlying the area of sensorimotor cortex. The SEP of each side were graded (bilaterally normal SEP's: grade-1/1, pathological SEP's grade-2/1 to grade-4/4). The aim of these recordings is to judge the probability of survival in adult comatous patients in the early phase after a head injury. Our retrospective analysis of these recordings in 108 patients (collective 1988/89) shows a significant correlation of the SEP with the Glasgow Coma Scale score (GCS) (GCS > 8/SEP grade-3 or grade-4: p < 0.005) and the pupillary function (pupillary function disturbed uni- or bilaterally/SEP grade-3 or grade-4: p < 0.0005), being less pronounced with the intracranial pressure (ICP) too. In patients with lack of the component N20 death or vegetative outcome is significantly more frequent than if this component is present (p < 0.005). All the 7 patients without recognisable bilateral component N20 (SEP grade-4/4) died as a consequence of the initial brain injury. 7 out of 9 patients with unilateral lack of the component N20 combined with diminished amplitude ratio and delayed central conduction time (CCT) contralaterally (SEP grade-4/3) died or survived in a vegetative condition; none of them became independent. If the results of the analysis of the patient collective 1988/89 were applied to the patients of 1990 (n = 67) a good correlation between SEP and outcome was confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

Kidney procurement from non-heartbeating donors: transplantation results

To overcome the shortage of kidneys (kdn's) available for transplantation we reactivated kdn procurement from non-heartbeating donors (NON-HBD). In this study, we reviewed our results with 34 kdn's from NON-HBD, transplanted between 1985 and 1991, and compared these with 34 control kdn's procured from heartbeating donors (HBD) matched for age, sex, primary graft or retransplant and transplant year. There was no difference in cold ischemia time, preservation solutions used, duration and type of preoperative dialysis, number of HLA mismatches and serum antibody levels between the two groups. The only significant findings were a lower diuresis in the last hour in the donors in the NON-HBD group, and a significantly higher serum creatinine level compared to the HBD group. The 1-year patient and graft survival rates were 89.4% and 84.9% for the HBD group, and 78% and 76.1% for the NON-HBD group respectively. There was need for dialysis support in the first posttransplant week in 10 out of 34 (29%) recipients in the HBD and 17 out of 34 (50%) recipients in the NON-HBD group. Primary non-function was observed in 1 of 34 (3%) recipients in the HBD group versus 3 of 34 (9%) in the NON-HBD group. None of the differences were statistically significant. There was also no difference in average serum creatinine levels at days 1, 3, and 7, at 1 month and at 1 year between the HBD and NON-HBD groups. In the NON-HBD group 6 of 34 kdn's (18%), 5 of which were retransplants, showed vascular rejection, 5 of them associated with haemolytic uremic syndrome (thrombotic microangiopathy); 2 of these 6 kdn's recovered, and 4 failed (2 with primary non-function). This important observation needs to be investigated further. The results is this study showed, however, that good short- and long-term results can be achieved with kdn's from NON-HBD. We concluded that organ procurement from NON-HBD is an adequate approach to an important cadaver donor source that in general is not effeciently used, but could significantly increase the number of kdn grafts in most transplant programs.

[Anesthesia for ambulatory procedures]

Ambulatory surgery and anesthesia continued to grow and develop over the last few years: Longer lasting and more complex diagnostic and therapeutic procedures are being performed on an outpatient basis. In addition, outpatient procedures, being less disruptive to the patient's everyday life, are of potential benefit especially for children and elderly patients. The proper selection and evaluation of these patients from the anesthesiological and surgical points of view are very important with regard to successful ambulatory interventions. The preoperative assessment is obviously essential. Good communication and teamwork between anesthesiologists, surgeons and admitting doctors are necessary. Patients should be informed early, i.e. before the day of operation, about the planned procedures (fasting periods, adult person necessary to accompany the patient home, etc.), and their written consent should be there. During the preoperative personal interview, the anesthesiologist identifies risk factors which may influence the management and outcome of the anesthetic procedure. Outpatients profit from a short-acting anxiolytic and sedative premedication before entering the operation room. The choice of the anesthetic procedure itself is made individually. An adequate intra- and postoperative monitoring is essential. A checklist with exact discharge criteria is helpful in practice.

[Enoximone as an alternative to mechanical circulatory support prior to heart transplantation]

Enoximone, a relatively new type III phosphodiesterase (PDE III) inhibitor with combined positive inotropic and vasodilating properties, was used as a pharmacological bridge to heart transplantation in a patient with severe dilatative cardiomyopathy (ejection fraction 11-13%), who developed cardiogenic shock refractory to conventional therapy with catecholamines and vasodilators. Enoximone led to an 88% increase in cardiac index (from 1.6 to 3.0 l/min.m2). Despite a noticeable rise in heart rate, stroke index increased by 57%. Systemic vascular resistance decreased by 48% without any relevant change in mean arterial pressure. Cardiac filling pressures remained high. Oxygen transport doubled and oxygen extraction ratio decreased by 10%. Apart from a decrease in arterial oxygen tension (from 15.8 to 12.8 kPa [119 to 96 mm Hg]), no other side effects were noted. Withdrawal of catecholamine therapy did not cause any relevant haemodynamic changes. Although complications arose from an uncontrolled septic state, orthotopic heart transplantation was performed with success 74 hours after initiation of enoximone therapy. As the PDE III inhibitor enoximone exerts its potent inotropic and vasodilating effects without requiring adrenergic receptor activation, it may be used as an alternative to mechanical support in patients who develop cardiogenic shock resistant to catecholamines while awaiting heart transplantation.

[X chromosome-linked mental retardation with fragile X chromosome and macro-orchidism]

Description of the first Swiss family with the new syndrome of X-linked mental retardation. The three brothers described are the first of all males traced back for four generations to be affected. In two of the brothers macroorchidism and the fragile X-chromosome were demonstrated, while the third brother died before diagnosis. As expected, the fragile X was not demonstrable in the 75-year-old mother of the three brothers.