[Principals of high frequency surgery]. / Hochfrequenzchirurgie -- Prinzipien und Anwendungen.

Electrosurgical instruments are routinely and daily applied at a variety of indications in Otorhinolaryngology. They can be used for cutting, coagulation and devitalisation. All have in common that the high frequency energy is transported into the tissue via an instrument and by this causes a thermal change. Depending on the duration and characteristic of the electricity a vaporisation of the tissue is effected through coagulation, devitalisation and carbonisation. The knowledge of the effects on the tissue by the choice of the different instrument parameters and application systems is essential for an ingenious therapeutically indication. In principal the following application methods for electrosurgery by modulation of the high frequency parameters are distinguished: the monopolar and the bipolar coagulation and devitalisation and the monopolar and the bipolar cutting. This article deals with the physical basis, the effects in the tissue as well as the single application methods of the high frequency surgery.

[Argon plasma coagulation and topically applied estriol. Long-term results in the treatment of hereditary hemorrhagic telangiectasia of the nasal mucosa]. / Argonplasmachirurgie und topische Estriolapplikation. Langzeitergebnisse in der Behandlung von hereditären hämorrhagischen Teleangiektasien der Nasenschleimhaut.

BACKGROUND AND OBJECTIVE: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant fibrovascular dysplasia with the main symptom of recurrent epistaxis. At present, only limited data are available on long-term results in the treatment of epistaxis. A part from the surgical treatment of the bleeding telangiectasia with argon plasma, an additional postoperative long-term treatment with estriol nose-ointment was performed and the results were analysed. PATIENTS AND METHODS: 69 patients with HHT were treated with APC and estriol nose ointment. 43 patients could be examined over a follow-up period of more than 20 months. The bleeding frequency and intensity as well as the patient's satisfaction with the treatment result were evaluated and the serum estriol level determined. RESULTS: After more than 20 months, the bleeding frequency and intensity were reduced in 95% of the patients compared to their preoperative findings. Under the influence of estriol, former berry-like telangiectasias became flatter and more even. Neither systemic side effects under topically applied estriol nor a relevant increase of serum estriol levels were observed. CONCLUSION: The combined treatment regimen with APC and topically applied estriol provides a new treatment concept of epistaxis in HHT.

Long-term results of inferior turbinate reduction with argon plasma coagulation.

OBJECTIVES: Surgical reduction of the inferior turbinates is a commonly used therapy in patients with hyperplastic inferior turbinates when medical management remains ineffective. Current surgical methods have disadvantages (e.g., necessity of nasal packing, extended postoperative swelling, and high costs). Theoretical considerations render argon plasma coagulation (APC) a promising new therapeutic approach. STUDY DESIGN: In a prospective study, 121 patients with chronic nasal obstruction were treated for inferior turbinate reduction with APC. Hyperplasia of the nasal turbinates was diagnosed rhinoscopically and endoscopically and confirmed rhinomanometrically. The mean follow-up period was 12 months, ranging from 10 to 16 months. The treatment results were evaluated by a questionnaire, rhinomanometric findings, and electron microscopic studies of the nasal mucosa. In 50 patients a ciliary function test was performed preoperatively and postoperatively. METHODS: Argon plasma coagulation, a high-frequency electrosurgery, has been used for volume reduction of the inferior turbinate in local anesthesia. RESULTS: Seventy-six percent of the patients reported an improvement of the postoperative swelling within the first week. After 6 weeks, macroscopically the turbinates were re-epithelialized by normal mucosa in 63% of the patients. Electron microscopic studies after 3 months verified normal cilia. After 12 months, 83% of the patients stated that they had a better nasal airflow than preoperatively. Crust formation was minimal. No bleeding or impaired ciliary function occurred. Ninety-five percent of the patients were willing to undergo the same operation again. CONCLUSION: The long-term results have proved APC to be an effective and easy-to-perform alternative for inferior turbinate reduction with comparable results to other established surgical methods.

Current advances in the basic research and clinical management of juvenile-onset recurrent respiratory papillomatosis.

Juvenile-onset recurrent respiratory papillomatosis is a relatively uncommon disease that presents clinically with symptoms ranging from hoarseness to severe dyspnea. Human papilloma viruses type 6 and 11 are important in the etiology of the papillomata and are most probably transmitted from mother to child during childbirth. Although spontaneous remission is frequent, a rare fatal course because of pulmonary spread or malignant transformation has occurred. CO2 laser evaporation of papillomas and adjuvant drug therapy using lymphoblastoid alpha-interferon are the most common treatment modalities at present. However, several other treatment modalities have been tried with varying success. Recent advances in basic research and different therapeutic approaches are reviewed.

Characterization of the expanded T cell population in infectious mononucleosis: apoptosis, expression of apoptosis-related genes, and Epstein-Barr virus (EBV) status.

Infectious mononucleosis (IM), a manifestation of primary infection with EBV, is characterized by a massive expansion of the T cell population. In this study we examined this expanded T cell population regarding its EBV status, its proliferative and apoptotic activity, and its expression of apoptosis-related genes. Whereas previous studies were performed on ex vivo cultures or on peripheral blood, our investigations included in vivo analysis of IM tonsillectomy specimens (14 cases) by in situ hybridization for viral RNA (EBERs) combined with immunohistochemistry (IHC; CD3, CD45RO, CD20, CD79a, Ki-67, Bcl-2, Bax, Fas, FasL) and the TUNEL method. Of the EBER+ cells 50-70% showed expression of the B cell markers CD20/CD79a. The remainder of the EBER+ cells expressed neither B nor T cell antigens. No co-expression of EBERs and T cell antigens was detected in any of the specimens. In accordance with a high rate of apoptosis (up to 2.37%) within the expanded T cell population, Bcl-2 expression was drastically reduced and FasL expression remarkably increased. The levels of Bax and Fas expression showed no or moderate up-regulation. In conclusion, the massive expansion of IM T cells is not caused by EBV infection of these cells but merely represents an intense immune reaction. Through altered expression of Bcl-2/Bax and Fas/FasL, the activated T cells are subject to enhanced apoptosis while residing within the lymphoid tissue, which eventually allows the efficient silencing of this potentially damaging T cell response.

The effect of In vitro hemodilution with gelatin, dextran, hydroxyethyl starch, or Ringer's solution on Thrombelastograph.

UNLABELLED: To determine the effects of progressive in vitro hemodilution with various plasma substitutes on whole blood coagulation, blood was obtained from six healthy volunteers. The Thrombelastograph((R)) (TEG; Haemoscope Corp., Morton Grove, IL) variables of reaction time, coagulation time, maximum amplitude, and growth angle were determined. The following plasma substitutes were tested: two gelatin solutions (4% gelatin polysuccinate and 5.5% oxypolygelatin); two dextrans (10% dextran 40 and 6% dextran 60); and five hydroxyethyl starch (HES) preparations (6% HES 70/0.5-0.55, 3% HES 200/0.5, 6% HES 200/0.5, 10% HES 200/0.5, and 6% HES 450/0.7). Ringer's solution was also tested to assist analyzing the intrinsic effect of colloid molecules on blood coagulation. The dilution ratios of citrated blood volume to plasma substitute volume were 10:2, 10:4, and 10:10. Blood coagulation was affected by plasma substitutes when the dilution ratios of citrated blood volume to colloid solution volume were 10:4 and 10:10. TEG variables did not change significantly after in vitro hemodilution with lactated Ringer's solution. The tested gelatin solutions showed less intrinsic effect on blood coagulation than other plasma substitutes. All HES preparations showed similar intrinsic effects as 6% dextran 60. The plasma substitute of 10% dextran 40 had the strongest effect on coagulation. Coagulation time was the most markedly affected TEG variable. Blood coagulation may be compromised when the dilution ratio of blood volume to colloid solution volume is >10:4. Whereas gelatin solutions have less intrinsic effect on blood coagulation, 10% dextran 40 has the strongest effect on coagulation. IMPLICATIONS: Blood coagulation may be compromised when the dilution ratio of blood volume to colloid solution volume is >10:4. Whereas gelatin solutions have less intrinsic effect on blood coagulation than hydroxyethyl starch or dextran, 10% dextran 40 has the strongest effect on coagulation.

Meconium and amniotic fluid embolism: effects on coagulation in pregnant mini-pigs.

OBJECTIVE: A hallmark of amniotic fluid embolism is the induction of coagulation defects. Little is known about the nature of these defects or the causative agent or agents. The purpose of this study was to assess the effects of meconium containing (native) meconium-amniotic-fluid infusion (MAFI) and meconium-free (centrifuged) amniotic-fluid infusion (AFI) on the coagulation system in the mini-pig model. DESIGN: Laboratory study. SETTING: University institute animal laboratory. SUBJECTS: Near-term pregnant Göttingen bred mini-pigs in three groups (control, MAFI, AFI) of six animals each. INTERVENTIONS: After induction of anesthesia, amniotic fluid was collected by cesarean section in all animals. Depending on the group, animals received either Ringer's solution (control), native amniotic fluid (MAFI), or centrifuged amniotic fluid (AFI) via an ear vein. MEASUREMENTS AND MAIN RESULTS: Blood samples were taken from a central vein before infusion (baseline), immediately after infusion, every 10 mins until 90 mins after infusion, and finally, every 20 mins until 150 mins after infusion. The following parameters were measured: Platelets, partial thromboplastin time, prothrombin time, fibrinogen, factors V, VII, VIII, antithrombin III, and protein C. The values relative to baseline in the MAFI and AFI groups were compared with control by rank order test. A p<.05 was considered statistically significant. Compared with the control group, platelets were lower in the MAFI group (p<.005), PTT was prolonged in both the MAFI and AFI groups (p<.005), fibrinogen was lower in both the MAFI and AFI groups (p<.05), prothrombin index was lower (i.e., prothrombin time was prolonged) in the MAFI group (p<.05), and protein C was lower in the MAFI group (p<.005). CONCLUSIONS: Both MAFI and, to a much lesser extent, AFI cause an activation of coagulation in mini-pigs. The changes induced by meconium-free AFI are probably not sufficient to explain the high mortality of the condition.

Preliminary observations on the Colibri CO2-indicator.

The performance of a new colorimetric CO2-indicator (Colibri) was assessed in mini-pigs. It performed well during 8-hour procedures. Neither nitrous oxide, nor halothane, nor carbon monoxide, nor intratracheal application of drugs (epinephrine, atropine, lidocaine, and naloxone) interfered with its function. It gave a distinct color change at high ventilation frequencies up to 120/min. The only problem observed was difficulty in matching the colors displayed with the comparison color chart provided. The Colibri's performance seems at least equal to that of the EasyCAP detector, although both devices share some disadvantages (no alarms, semiquantitative, difficult reading in the dark). After initial control of endotracheal tube position by an esophageal detector device, both the Colibri and the EasyCAP seem suited for monitoring of ventilation and circulation if quantitative capnometry is unavailable.

Oximetry for amniotic fluid embolism detection in mini-pigs: tail or snout?

The continuous, non-invasive real-time monitoring of arterial oxygenation (pulse oximetry) has become a standard of care in both human and veterinary medicine. It allows reliable, simple and inexpensive assessment of the arterial oxygenation status. In pigs, commonly used sites for oximetry-probe placement are the ear, snout or tongue, while more recently the 'pig-tail oximetry' has been suggested. In a study regarding the coagulation system during amniotic fluid embolism (AFE) in mini-pigs, we compared tail and snout for oximetry-probe placement and compared them with the 'gold standard': blood-gas analysis (BGA). In both the AFE group and the control group, the tail measurements were slightly lower and the snout measurements were slightly higher than the BGA results. In the experimental model used, both tail and snout measurements were able to detect a temporary desaturation immediately after amniotic fluid embolism (AFE). Blood-gas analysis (BGA) performed on blood drawn from a large artery missed the event. Clinically, there is no significant difference between snout and tail as oximetry-probe placement sites: both are reliable oximetry sites in mini-pigs.

[Preclinical control of intubation and artificial respiration. Animal experiment and literature review]. / Präklinische Kontrolle von Tubuslage und Beatmung. Tierexperimentelle Studie und Literaturübersicht.

Oesophageal malposition of an endotracheal tube is among the leading causes of anaesthesia incidents. While clinical manoeuvres for detection of tube malposition are unreliable, monitoring (i.e. capnography) can prevent such incidents. The problem is particularly important in prehospital care, where capnography is not (yet) widely available. We tested three devices used for differentiating oesophageal from endotracheal intubation: 1. Non-CO2-dependent Oesophageal Detector Device (ODD) as described by Pollard and Wee, 2. Semi-quantitative chemical disposable capnometer EasyCAP (Nellcor), 3. Non-quantitative infrared miniaturised capnometer MiniCAP (MSA). METHODS. 50 anaesthetised minipigs were intubated with a Magill tube. An identical additional tube was placed in the oesophagus. The cuffs of both tubes were inflated. Unexperienced personnel (students, laboratory technicians) were asked to determine the position of one of the tubes by using one of the devices according to the randomisation plan. The decision had to be taken within 30 s. Using the ODD, the proband first injected 100 ml air into the lung (or stomach) and then tried to aspirate the same volume. EasyCAP and MiniCAP were used according to manuals. RESULTS. Each device was used 25 times with a tracheal tube and 25 times with an oesophageal tube. All tube position identifications were correct. When ventilating the oesophagus/stomach for capnometric control, regurgitation into the tube occurred six times (five times with the EasyCAP and once with the MiniCAP). In these cases, the decision was based on this occurrence and not on the display of the device. While using the ODD no regurgitation occurred. CONCLUSION. These devices are useful for preclinical practice. According to the literature and our experience, the ODD is superior for the initial control of tube position, especially in cardiac arrest. Capnometry is needed, however, for continuous control of ventilation.