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At least 199 records · Page 11Linked to original sources
PubMed1992

[Thoracoscopic laser coagulation shrinkage of blebs in the treatment of spontaneous pneumothorax].

As a thoracoscopic treatment for spontaneous pneumothorax, electrocautery has been mainly used. But contact type electrocautery has a risk of perforation of blebs. We adopted carbon monoxide laser (wave length 5.4 microns) and good coagulation shrinkage of blebs could be obtained by non-contact irradiation. CO laser was delivered by As-S glass fiber and power of fiber tip was 2-4 W. Compared with Nd-YAG laser (wavelength 1.06 microns), CO laser showed lower risk of perforation of blebs. Thoracoscopic CO laser coagulation shrinkage of blebs proved to be a important method of treatment for patient of spontaneous pneumothorax.

Humans↗
PubMed2006

Maternal hemodynamic changes following treatment by laser coagulation of placental vascular anastomoses and amnioreduction in twin-to-twin transfusion syndrome.

OBJECTIVES: To investigate maternal hemodynamic changes following laser therapy and amnioreduction in twin-to-twin transfusion syndrome (TTTS). METHODS: Thirty-nine cases with severe TTTS were treated at 16-26 weeks of gestation. Maternal hemodynamic evaluation was performed, including heart rate (HR), arterial pressure and echocardiography with calculation of shortening fraction (SF), left atrial dimensions, stroke volume (SV), cardiac output (CO) and total vascular resistance (TVR), before and 6 h and 24 h after placental surgery. Hemoglobin (Hb), hematocrit (Ht) and protein levels were also measured. Cases were retrospectively divided into groups according to treatment: Group A had laser therapy followed by amnioreduction >1000 mL (n = 25); Group B had laser therapy followed by amnioreduction <1000 mL (n = 14). RESULTS: The mean gestational age at inclusion was 21 (range, 16-26) weeks. The mean amniotic fluid withdrawal was 1700 (range, 1000-3000) and 300 (range, 150-800) mL in Groups A and B, respectively. Cases in Group A showed a decrease in mean arterial blood pressure (P = 0.011) and in TVR (P < 0.0001) and an increase in CO (P = 0.008) and SV (P = 0.022). There was no difference in HR. Significant hemodilution developed as early as 6 h after the procedure, with a reduction in Ht (P < 0.0001), plasma protein (P < 0.0001) and Hb levels of 1.2 g/dL on average (P < 0.0001). There were no changes in any parameters in Group B. CONCLUSIONS: Amnioreduction of severe polyhydramnios in TTTS induces maternal hemodynamic changes within the first 6 h that persist at least 24 h after treatment. These adaptative changes are compatible with hemodilution.

Adult↗
PubMed2005

Persistent elevation of cell-free fetal DNA levels in maternal plasma after selective laser coagulation of chorionic plate anastomoses in severe midgestational twin-twin transfusion syndrome.

OBJECTIVE: This study was undertaken to determine whether laser thermocoagulation for twin-twin transfusion syndrome (TTTS) causes increased cell-free fetal DNA levels in maternal plasma, potentially as a result of placental injury. STUDY DESIGN: We enrolled 34 patients with twin pregnancies complicated by severe TTTS who underwent fetoscopic selective laser ablation of placental vascular anastomoses. Blood samples were drawn before and sequentially after the procedure. Fetal DNA in maternal plasma was quantified by polymerase chain reaction amplification of a Y-chromosome sequence. RESULTS: Compared with baseline, median elevations of fetal DNA levels were 0.8% at 30 minutes ( P = .32), 15.8% at 60 minutes ( P = .1), 179.5% at 24 hours ( P = .003), and 172.9% at 48 hours ( P = .003). Factors associated with increased fetal DNA levels at 24 hours after procedure included longer operation time, higher number of vessels ablated, and subsequent in utero fetal death ( P = .01, .04, and .04, respectively). CONCLUSIONS: Persistent elevation of fetal DNA levels in maternal plasma after laser ablation suggests that circulating fetal DNA could derive from placental injury. Plasma fetal DNA analysis may be an additional prognostic marker for fetal outcome after laser therapy.

DNA↗
PubMed1995

Technique and results of interstitial laser coagulation.

By use of thermal "ablation" techniques to apply heat to the prostate from the urethra, the coagulation volume is limited by the limited penetration depth of suitable radiation sources, e.g., lasers, and by heat conduction. Secondarily, the coagulated tissue is removed by sloughing. Interstitial heat application was expected to overcome these problems. Our initial in vitro and animal studies using different light guides for interstitial Nd:YAG laser radiation showed that small, carbonized lesions were created by bare fibers, whereas large, homogeneous coagulation zones measuring up to 2 cm in diameter were produced by specially designed ITT (interstitial thermotherapy) fibers, which secondarily resulted in marked volume reduction by atrophy. Further experiments using such applicators resulted in an operation technique suitable for clinical routine in the treatment of symptomatic benign prostatic hyperplasia (BPH). These laser applicators are inserted into the prostate either transurethrally through a cystoscope under direct vision or percutaneously from the perineum under transrectal ultrasound guidance. The number of placements depends on the size and configuration of the gland. Radiation parameters were optimized for each system. To avoid charring, relatively low levels of laser power and long radiation periods (e.g., 7 W for 10 min) or power-formatting programs (e.g., stepwise reduction of power from 20 to 7 W for a total radiation time of 3 min) are applied. Beginning in July 1991, more than 350 unselected patients with BPH were treated with interstitial laser coagulation in our department, of whom 239 were followed for at least 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1997

Transcatheter neodymium-yttrium-aluminum-garnet laser coagulation of canine ventricle using a balloon-tipped cardioscope.

The feasibility of transcatheter laser ablation of the canine left ventricle (LV) was tested using a newly developed cardioscope. In 17 anesthetized dogs, a combined laser-endoscope catheter, consisting of an endoscope encased in a 7-French flexible catheter with an inflatable and transparent balloon at the distal end, was introduced into the LV via the carotid artery. A 1064-nm neodymium-yttrium-aluminum-garnet (Nd:YAG) laser was delivered by laser optic fiber, which was introduced through the transport channel and positioned inside the saline-filled balloon. In 16 of 17 dogs, the endocardial surface of the LV was clearly observed. Laser energy totaling 500-5,000 J was applied sequentially in 13 dogs and laser irradiation was completed in all but 2 of the dogs. The excised hearts revealed well-demarcated oval-shaped lesions 2.5-9.5 mm deep in 7 of 11 dogs. Histologic sections revealed coagulation necrosis surrounded by a rim of contraction band necrosis. Thus, transballoon laser photocoagulation of the beating LV is feasible. The newly combined laser-endoscope catheter, which is still in its preliminary stages and needs to be improved to increase the success rate of photocoagulation, appears to be a promising alternative modality for catheter ablative therapy for ventricular tachycardia.

Animals↗
PubMed2006

Prevalence and management of late fetal complications following successful selective laser coagulation of chorionic plate anastomoses in twin-to-twin transfusion syndrome.

OBJECTIVE: This study was undertaken to report on the prevalence and management of late complications in twin-to-twin transfusion syndrome (TTTS) treated by laser therapy when both twins are alive 1 week after surgery. STUDY DESIGN: A total of 151 consecutive TTTS cases were treated by selective fetoscopic laser therapy. Cases in which both twins were alive 1 week after surgery were followed up with ultrasound and Doppler examination, including middle-cerebral artery peak systolic velocity measurement (MCA-PSV). RESULTS: In the 151 cases treated with laser, both twins were still alive 7 days after the procedure in 101 cases. Intrauterine death of 1 and both twins occurred in 7 and 1 cases, respectively. Recurrence of TTTS with the polyhydramnios-oligohydramnios sequence occurred in 14 (14%) cases. In another 13 (13%) cases, amniotic fluid remained normal in both sacs, but MCA-PSV increased above 1.5 MoM in 1 twin and decreased concomitantly below 0.8 MoM in the co-twin. This was related to anemia and polycythemia, respectively, and resulted from unidirectional feto-fetal blood transfusion, mainly from former recipients into former donors. Late complications were managed accordingly by repeat laser, amnioreduction, cord coagulation, intrauterine blood transfusion, or elective delivery. CONCLUSION: MCA-PSV Doppler measurements are useful in the follow-up of double survivors to detect and manage late complications after selective laser therapy.

Anemia↗