Biomedical subjects

Georg Matheis

Publications and source records attributed to Georg Matheis.

6 recordsLinked to original sources

PubMed2003

Occupational exposure to inhalational anesthetics during cardiac surgery on cardiopulmonary bypass.

BACKGROUND: Eventual hazards from occupational exposure of operating room personnel to inhalational anesthetic agents cannot yet be definitively excluded. We determined if occupational exposure of operating room personnel to waste anesthetic gases during cardiopulmonary bypass (CPB) complies with the established governmental limits. METHODS: Ten adults underwent inhalational anesthesia for coronary artery bypass grafting with nitrous oxide and either sevoflurane (n = 5) or desflurane (n = 5). The administration of inhalational anesthetic agents was stopped before initiation of CPB. Gas samples were obtained before and during CPB every 90 seconds from the breathing zones of anesthesiologist (A), surgeon (S), and perfusionist (P). Time-weighted averages (TWA) over the time of exposure were calculated. RESULTS: The surgeon's exposure to nitrous oxide was 9.3 +/- 1.9 parts per million (ppm) before and 3.0 +/- 1.4 ppm during CPB (A: 6.7 +/- 1.1 ppm and 0.5 +/- 0.1 ppm; P: 3.7 +/- 1.4 ppm during CPB). Occupational exposure to desflurane was 0.21 +/- 0.10 ppm before and 0.62 +/- 0.28 ppm during CPB for the surgeon (A: 0.02 +/- 0.01 ppm and 0.02 +/- 0.003 ppm; P: 0.82 +/- 0.26 ppm during CPB), thereby exceeding the given limit of 0.5 ppm. Exposure levels of sevoflurane were below the 0.5 ppm limit at all times, as were nitrous oxide levels (threshold limit: 25 ppm). CONCLUSIONS: Although occupational exposure to inhalational anesthetic agents was low at most times during the study and none of the operating room staff complained about subjective or objective impairment or discomfort, all measures must be taken to further minimize occupational exposure, including sufficient air conditioning and routine use of waste gas scavenging systems on CPB equipment.

Adult↗

PubMed2003

Cariporide (HOE642) limits S-100B release during cardiac surgery.

Cardiac surgery with cardiopulmonary bypass (CPB) results in transient cerebral swelling in most patients. Cognitive decline occurs in 24-57% of patients and 2-5% experience stroke. Serum levels of S-100B, a potential marker of increased blood-brain barrier permeability, increase during and early after surgery. The authors studied the effects of the novel Na /H exchange inhibitor cariporide (HOE642) on postoperative serum levels of S-100B and neuron-specific enolase (NSE) in 53 patients at high risk undergoing coronary artery bypass grafting. Patients were randomly assigned to one of four groups: I, placebo; II, 20 mg cariporide; III, 80 mg cariporide; IV, 120 mg cariporide). In addition, the leukocyte activation marker myeloperoxidase (MPO) and malondialdehyde (MDA), a marker for lipid peroxidation, were evaluated by enzyme-linked immunoassay. Postoperatively, five patients experienced transient ischemic attack or stroke. S-100B levels increased from 0.43 microg/l +/- 0.33 before operation to 2.27 microg/l +/- 0.69 1 hour after surgery in the placebo group. Preoperative S-100B levels in the HOE642 groups did not differ from the placebo group whereas, 1 hour after surgery, levels were significantly lower in groups II, III, and IV (1.63 microg/l +/- 0.2, 1.27 microg/l +/- 0.27, and 0.90 microg/l +/- 0.21, respectively). NSE, MPO, and MDA serum levels did not differ among groups. These findings may stimulate larger clinical studies to examine the effects of HOE642 on cerebral swelling and neurologic/cognitive outcome of cardiac surgery with CPB.

Aged↗

PubMed2003

New technologies for respiratory assist.

"The artificial lung especially has lingered behind progress with artificial hearts and ventricular assist devices, not because the need for lungs has not been recognized, but because we have not had a full understanding of the engineering problems and the unique material requirements until recent years." Brack Hattler, MD PhD. The development from the first clinical use of haemodialysis over five decades ago to widespread chronic treatment took more than two decades. The histories of other artificial organ technologies, such as artificial hearts, follow similar long development paths. For five decades, due to a lack of technology, artificial lungs have been limited to use with a heart-lung machine for cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO). The advent of pumpless biocompatible artificial lungs will open new treatment options for patients with acute or chronic lung failure.

Artificial Organs↗

PubMed2003

Graded reoxygenation limits lipid peroxidation during surgical reperfusion.

BACKGROUND: Most cardiac operations with cardiopulmonary bypass (CPB) are conducted with high oxygen partial pressure. The hyperoxic reoxygenation of the ischemic heart induced by aortic declamping may be an important component of cardiac reperfusion injury. The present clinical study assessed the preventive effect of graded reoxygenation on lipid peroxidation. Malondialdehyde (MDA) levels reflect lipid peroxidation, and therefore can be used to quantify reoxygenation damage. MATERIAL/METHODS: 19 patients with coronary artery disease were enrolled consecutively and divided into two groups. In Group I, graded reoxygenation was initiated 1 min before, and continued for 9 min after aortic declamping (paO2: 50-70 mmHg, n=10). Patients undergoing conventional hyperoxic reoxygenation (paO2: >250 mmHg) on CPB (Group II, n=9) served as controls. Blood was collected before commencement of CPB, 2 min before release of the aortic crossclamp, 1 min and 10 min after release of the aortic crossclamp, and 3 hours after CPB. RESULTS: MDA levels [KM/l] did not differ between groups before CPB, but 1 min after aortic declamping MDA increased significantly more in group II (11.02 +/- 1.05; p=0.04) as compared to group I (8.16 +/- 0.74). There was no difference between groups late after reperfusion. CONCLUSIONS: Hyperoxic reoxygenation by release of the aortic crossclamp is associated with increased MDA levels immediately after aortic declamping. Graded normoxic reoxygenation therefore limits lipid peroxidation in the early reperfusion period.

Aged↗

PubMed2002

Coronary artery bypass grafting through complete sternotomy in conscious patients.

BACKGROUND: Complete sternotomy is the standard approach in cardiac surgery, and coronary artery bypass grafting (CABG) is the most common revascularization procedure to use this approach. A new technique has been developed that permits complete surgical revascularization with arterial grafts in awake patients. This technique, which we refer to as awake coronary artery bypass grafting, avoids general anesthesia, mechanical ventilation, and extracorporeal circulation, thereby creating the least invasive method for heart operations yet described. METHODS: A thoracic epidural catheter was placed at T2-T3 level one day before surgery. In 12 patients, single (n = 6), double (n = 5), or triple (n = 1) vessel coronary artery bypass grafting was performed without general anesthesia. In six patients, this procedure was performed after complete median sternotomy. RESULTS: Ten patients remained awake throughout the whole procedure. Two patients required secondary intubation due to incomplete analgesia in one case and pneumothorax in the other. Procedural time was 98.2 +/- 19.8 minutes. Intermediate care stay was 4.9 +/- 0.6 hours. There were no perioperative complications, and early angiographic results before discharge were excellent in all patients. CONCLUSIONS: The data presented show the feasibility and safety of complete surgical revascularization via median sternotomy using arterial grafts without general anesthesia. This approach shortens recovery time and increases patient comfort, suggesting that outpatient cardiac surgery may eventually be possible.

Aged↗

PubMedDate not supplied

Myocardial rewarming mirrors intraoperative mammary artery graft function.

BACKGROUND: The internal mammary artery (IMA) bypass graft provides a satisfactorily long-lasting blood supply to the myocardium. However, its initial flow capacity can be insufficient with subsequent regional myocardial ischemia. We evaluated a method to assess the IMA graft function intraoperatively. METHODS: Twenty-five patients with three-vessel coronary artery disease underwent coronary artery bypass grafting on cardiopulmonary bypass. The in situ IMA was grafted to the left anterior descending coronary artery (LAD) in combination with two saphenous vein grafts to the left circumflex and right coronary artery. Distal anastomoses were performed during cold intermittent blood cardioplegia. After unclamping of the aorta and of the grafted IMA, the temperature at the cardiac anterior and posterior side was measured during the first 5 minutes of warm reperfusion. RESULTS: A sufficient IMA graft function was expressed by a typical rise in temperature: the cardiac anterior and posterior sides showed a parabolic and exponential course, respectively. The rewarming velocity expressed as the first derivative of temperature over time led to a sharp and early peak for the anterior side, and a smaller and delayed peak for the posterior side. Insufficient IMA graft function could be recognized by an atypical temperature course. CONCLUSIONS: Temperature measurement of the heart during warm reperfusion after hypothermic cardioplegia can help to assess the effectiveness of the IMA-LAD graft function.

Coronary Angiography↗