Temporally versatile polarization entanglement from Bragg reflection waveguides.

Bragg reflection waveguides emitting broadband parametric downconversion (PDC) have been proven to be well suited for the on-chip generation of polarization entanglement in a straightforward fashion [Sci. Rep.3, 2314 (2013)SRWSDA2045-232210.1038/srep02314]. Here, we investigate how the properties of the created states can be modified by controlling the relative temporal delay between the pair of photons created via PDC. Our results offer an easily accessible approach for changing the coherence of the polarization entanglement, in other words, to tune the phase of the off-diagonal elements of the density matrix. Furthermore, we provide valuable insight into the engineering of these states directly at the source.

Uncovering dispersion properties in semiconductor waveguides to study photon-pair generation.

We investigate the dispersion properties of ridge Bragg-reflection waveguides to deduce their phasematching characteristics. These are crucial for exploiting them as sources of parametric down-conversion (PDC). In order to estimate the phasematching bandwidth we first determine the group refractive indices of the interacting modes via Fabry-Perot experiments in two distant wavelength regions. Second, by measuring the spectra of the emitted PDC photons, we gain access to their group index dispersion. Our results offer a simple approach for determining the PDC process parameters in the spectral domain, and provide important feedback for designing such sources, especially in the broadband case.

Use of surface acoustic waves to reduce pain and discomfort related to indwelling nasogastric tube.

BACKGROUND AND STUDY AIMS: Nasogastric intubation, one of the most widely utilized therapeutic procedures in medical practice, is associated with trauma, pain, and discomfort, which can occur both at insertion and during the indwelling phase. Although lubricating jelly is useful during the insertion phase, insertion can still cause great discomfort. Furthermore, the jelly is rapidly absorbed and therefore is unable to decrease the friction between the tissues and the tube during the indwelling phase of the nasogastric tube. The aim of this study was to test a device, the NG-Shield, that generates surface acoustic waves on the surfaces of the nasogastric tube to reduce contact time and thus friction between the nasogastric tube and body tissues. PATIENT AND METHODS: Twenty-four healthy volunteers were enrolled in a single-center, crossover, blinded study, in which a nasogastric tube was inserted and left indwelling for 6 hours. Throughout the indwelling period the device was activated and deactivated alternately every hour, and the volunteers were questioned every hour about their pain and discomfort levels as well as grading pain and discomfort upon insertion and removal of the nasogastric tube. Pain and discomfort levels were compared between active and nonactive phases of the device. RESULTS: The activated NG-Shield was found to reduce both pain and discomfort significantly in both the nose and throat throughout the indwelling phase. CONCLUSIONS: The NG-Shield is a safe and effective device for reducing pain and discomfort associated with an indwelling nasogastric tube.

New support for ophthalmic drapes.

A new flexible support for ophthalmic drapes with the possibility of continuous oxygen supplementation was designed for use in patients undergoing eye surgery under local anesthesia. This new equipment is easy to handle and prevents contact between the patient's face and the ophthalmic drape. To prevent hypoxia of spontaneously breathing patients, the ambient air under the drapes can be supplemented with oxygen using this new equipment and no other devices. The equipment described here is advantageous for practical use in patients undergoing eye surgery under retrobulbar anesthesia.

New equipment to prevent carbon dioxide rebreathing during eye surgery under retrobulbar anaesthesia.

BACKGROUND: Carbon dioxide concentration under ophthalmic drapes increases during eye surgery under local anaesthesia. A new prototype has been designed which combines continuous suction of carbon dioxide enriched air and continuous oxygen insufflation under ophthalmic drapes to prevent carbon dioxide accumulation in spontaneously breathing patients undergoing cataract surgery. METHODS: In a prospective randomised single blind study the effectiveness of this new prototype was examined in 50 unpremedicated elderly patients. In 25 patients suction was applied under ophthalmic drapes, whereas in the other 25 patients no suction was used. In all cases oxygen was insufflated under the drapes at a constant flow of 2 l/min. Carbon dioxide concentration in the ambient air surrounding the patient's head under ophthalmic drapes, transcutaneous partial pressure of carbon dioxide, respiratory rate, and oxygen saturation were measured. RESULTS: Carbon dioxide concentration under the drapes, transcutaneous partial pressure of carbon dioxide, and respiratory rate remained unchanged in the suction group, whereas in the non-suction group these values increased significantly. Oxygen saturation rose significantly in both groups without differences between the groups. CONCLUSION: Application of this new prototype for continuous aspiration of carbon dioxide enriched air prevents carbon dioxide rebreathing and subsequent hypercapnia associated with an elevated respiratory rate. This new equipment may therefore be useful in patients undergoing ophthalmic surgery under retrobulbar anaesthesia.

Oxygen application by a nasal probe prevents hypoxia but not rebreathing of carbon dioxide in patients undergoing eye surgery under local anaesthesia.

BACKGROUND/AIM: Hypoxia and carbon dioxide rebreathing are potential problems during eye surgery in spontaneously breathing patients. The aim of the present study was to determine effectiveness of nasal application of oxygen to prevent hypoxia and carbon dioxide accumulation in spontaneously breathing patients undergoing cataract surgery. METHODS: Oxygenation and carbon dioxide rebreathing were examined in 40 elderly patients using two different methods of oxygen supply-nasal v ambient air-with a constant flow of 2 l/min. Partial pressure of carbon dioxide under ophthalmic drapes, transcutaneous pressure of carbon dioxide, and the respiratory rate were measured during 25 minutes while oxygen was supplied via a nasal cannula or into the ambient air under the drapes. RESULTS: In both groups carbon dioxide accumulation under the drapes, carbon dioxide rebreathing, tachypnoea, and an increase in peripheral oxygen saturation occurred. No significant differences were found between the two methods. CONCLUSION: Nasal application of oxygen prevented hypoxia but did not prevent carbon dioxide accumulation in patients undergoing eye surgery under retrobulbar anaesthesia. Additionally, as a side effect when using nasal probes, irritation of the nose was described in half of the patients investigated.

Heat trapped under paper and plastic ophthalmic drapes during eye surgery using local anesthesia.

PURPOSE: To assess whether heat trapped under ophthalmic drapes is responsible for patient reports of being hot during cataract surgery using local anesthesia. SETTING: Departments of Anaesthesia and Intensive Care Medicine and of Ophthalmology and Optometry, Innsbruck University Hospital, Innsbruck, Austria. METHODS: In a prospective, randomized, single-blind study, the temperature in the ambient air under 2 types of paper drapes (Group A: Barrier Ophthalmology Drape, Johnson & Johnson; Group B: Steri Drape 1062, 3M) and a plastic drape (Group C: cotton drape + Steri Drape 1024, 3M) was measured for 25 minutes in 60 patients having cataract surgery under local anesthesia. RESULTS: Three minutes after the patient's head was draped, the mean temperature under the drape began to increase significantly: Group A, 25.7 degrees C +/- 0.3 degree C (SD) to 29.17 degrees C +/- 0.9 degree C (P < or = .001); Group B, 25.87 degrees C +/- 0.4 degree C to 29.41 degrees C +/- 0.9 degree C (P < or = .001); Group C, 25.8 degrees C +/- 0.35 degree C to 29.4 degrees C +/- 0.6 degree C (P < or = .001). It continued to increase in all groups as the operation continued. No significant differences in temperature were observed among the 3 drape types studied. Subjective thermal discomfort was reported by 35% to 40% of patients. CONCLUSION: Paper drapes did not cause less heat from being trapped than the plastic drape. Trapped heat may impair the comfort of patients having eye surgery under local anesthesia.

Healing of burns after treatment with 670-nanometer low-power laser light.

Recent investigations have reported contradictory results on the influence of low-power laser light on wound healing. Low-power laser with a power output of 250 mW and an emitted laser light of 670 nm have been insufficiently investigated to date. The effect of a 250-mW/670-nm laser light on the healing of burning wounds in rats was investigated. Thirty rats were burned on both flanks. One wound was irradiated with 670-nm laser light (2 J/cm2), whereas the other side remained untreated. Macroscopic evaluation of the wounds was performed daily; 10, 20, and 30 days after burning, 10 rats were killed and the wounds histologically evaluated. Neither macroscopic nor histologic examination of the irradiated wound showed accelerated wound healing when compared with control wounds. In the present study, irradiation of burns with a 250-mW/670-nm laser light produced no beneficial effects on wound-healing processes.

Can midazolam diminish sufentanil analgesia in patients with major trauma? A retrospective study with 43 patients.

Benzodiazepine agonists in combination with opioid analgesics are commonly used for combined analgesia and sedation in intensive care patients as well as for anesthesia. In animals, studies indicate either agonistic or antagonistic interactions of benzodiazepine agonists and opioids. This retrospective study of 43 patients evaluated the possible clinical relevance of benzodiazepine-opioid interactions related to pain management. We observed an increase of greater than 50% of the maximal sufentanil infusion rate in significantly more patients in group 2 (13 patients vs 6 patients; chi 2: p = 0.04) and a decrease of the sufentanil infusion rate in eight group 1 patients, but only in one patient in group 2 (chi 2: p = 0.03). We believe that an interaction between midazolam and sufentanil on nociceptive transmission and/or a rapid development of tolerance to sufentanil may be responsible for the observed difference. Contrary to the common clinical impression that midazolam potentiates opioid analgesia, these results indicate that systemic co-administration of midazolam over a period of more than three days can diminish sufentanil efficacy.

Intraventricular injection of 6-hydroxydopamine results in an increased number of tyrosine hydroxylase immune-positive cells in the rat cortex.

Previously we have demonstrated that intraventricular injection of 6-hydroxydopamine (6-OHDA) results in increased proliferation and de-differentiation of rat cortical astrocytes into progenitor-like cells 4 days after lesion (Wachter et al., 2010). To find out if these cells express tyrosine hydroxylase (TH), the rate-limiting enzyme in the catecholamine synthesis pathway, we performed immunohistochemistry in the rat cortex following intraventricular injection of 6-OHDA. Four days after injection we demonstrated a strong emergence of TH-positive (TH(+)) somata in the cortices of 6-OHDA-lesioned animals. The number of TH(+) cells in the cortex of 6-OHDA-lesioned animals was 15 times higher than in sham-operated animals, where virtually no TH(+) somata occurred. Combining TH immunohistochemistry with classical Nissl stain yielded complete congruency, and ∼45% of the TH(+) cells co-expressed calretinin, which indicates an interneuron affiliation. There was no co-staining of TH with other interneuron markers or with glial markers such as glial fibrillary acidic protein (GFAP) or the neural stem/progenitor marker Nestin, nor could we find co-localization with the proliferation marker Ki67. However, we found a co-localization of TH with glial progenitor cell markers (Sox2 and S100ß) and with polysialylated-neural cell adhesion molecule (PSA-NCAM), which has been shown to be expressed in immature, but not recently generated cortical neurons. Taken together, this study seems to confirm our previous findings with respect to a 6-OHDA-induced expression of neuronal precursor markers in cells of the rat cortex, although the TH(+) cells found in this study are not identical with the potentially de-differentiated astrocytes described recently (Wachter et al., 2010). The detection of cortical cells expressing the catecholaminergic key enzyme TH might indicate a possible compensatory role of these cells in a dopamine-(DA)-depleted system. Future studies are needed to determine whether the TH(+) cells are capable of DA synthesis to confirm this hypothesis.

Prospective, randomized-controlled trial comparing postoperative pain after plug and patch open repair with totally extraperitoneal inguinal hernia repair.

PURPOSE: The aim of this study was to compare postoperative pain between the open tension-free plug and patch (PP) technique and the totally extraperitoneal patch (TEP) hernioplasty. METHODS: One hundred and fifty-four male patients with unilateral inguinal hernia were randomized to undergo PP and TEP from 2005 to 2009. Pain assessment was conducted using the numerical rating scale (NRS) and the McGill Pain Questionnaire preoperatively, 6, 12 and 24 months postoperatively. All patients received the same analgesic regimen and documented pain in a NRS-based 4-week diary. RESULTS: Of the 154 patients 77 underwent TEP and 77 PP. Median follow-up was 3.8 years. One recurrent hernia was observed in the TEP and two in the PP group (p = 0.56). Median preoperative NRS scores were 2 and 2, 0.3 and 0.4 at 6 months, 0.1 and 0.3 at 12 months, 0.2 and 0.1 at 24 months postoperatively in the PP and TEP groups, respectively (p > 0.05). Data from the 4-week pain diaries revealed significant differences in pain intensity between the two different techniques from the second postoperative week (p < 0.05). Patients in the PP group required more additional analgesics on day four and five postoperatively (p = 0.037 and 0.015, respectively). CONCLUSIONS: Our data favor the TEP technique concerning postoperative pain as primary endpoint between tension-free PP and TEP hernia repair.

Trans-fascial laparoscopic mesh fixation: a procedural comparison using the standard suture passer versus iMESH stitcher™ device.

INTRODUCTION: Laparoscopic mesh repair has become an increasingly common method for repairing incisional hernias. The current method for fixating mesh to the abdominal wall includes tacking the mesh to the peritoneum and fascia and suturing the mesh to the fascia with trans-fascial sutures. The iMESH Stitcher™ is a stitching device developed to both simplify and expedite this procedure by passing the suture from one arm of the iMESH stitcher™ to the other. The device enables a stitch to be created in three quick moves using only one hand. We compared both the efficacy and procedure time of trans-fascial mesh fixation when performed with the iMESH stitcher™ as compared to the standard suture passer method. METHODS: A mesh patch was installed on the internal abdominal wall of two pigs. Surgical residents and Medical students were participants in the study and were trained in both techniques. Each participant was asked to perform six fixations with each technique. The procedural time required for both fixation techniques was recorded. Participants were asked to assess subjectively the relative difficulty of each technique on a scale of 1-10 (10 = most difficult). RESULTS: Sixteen residents and students performed a total of 12 mesh fixations, each performing 6 fixations with each technique. Average mesh fixation suture time using the suture passer technique was 44 s for residents and 47 s for students. Average fixation suture time using the iMESH stitcherTM was 17 s for residents and 15 s for students. The average difficulty score for the suture passer technique was 6.1 as compared to 2.9 with iMESH stitcher™. CONCLUSION: Trans-fascial fixation with the iMESH Stitcher™ took significantly less time than the standard suture passer method. The iMESH Stitcher™ significantly simplifies the procedure of transfascial fixation and potentially reduces technical difficulties.

Accumulation of carbon dioxide under ophthalmic drapes during eye surgery: a comparison of three different drapes.

Carbon dioxide accumulation under ophthalmic drapes is caused by their impaired permeability to exhaled carbon dioxide in spontaneously breathing patients. Three different ophthalmic drapes were examined under clinical conditions. Sixty unpremedicated patients of each gender, aged over 60 years and with an ASA status of I-III undergoing cataract surgery under retrobulbar anaesthesia were included in the study. Patients with known pulmonary diseases were excluded. The patients were divided into three groups of 20 patients each. In all groups, oxygen was insufflated under the drapes at a constant flow of 21.min-1. Carbon dioxide concentration in the inspired air, transcutaneous carbon dioxide pressures, respiratory rate and oxygen saturation by pulse oximetry were measured. Accumulation of carbon dioxide under the drapes, increase of partial pressure of transcutaneous carbon dioxide and hyperventilation were observed in all three groups. An oxygen supply of 21.min-1 prevented hypoxaemia but not hypercapnia. Therefore, producers of ophthalmic drapes are encouraged to look for further ways to increase the carbon dioxide permeability of their drapes with the aim of reducing carbon dioxide accumulation and hyperventilation in spontaneously breathing patients undergoing eye surgery.

[Acupuncture in prevention of postoperative nausea and vomiting]. / Akupunktur in der Prophylaxe von postoperativer Ubelkeit und Erbrechen.

In this review the effectiveness of the acupuncture point Pericard 6 (P 6) on postoperative nausea and vomiting (PONV) is described. Use of the acupuncture, acupressure as well as the laser stimulation of P 6 proved as efficient prophylaxis of PONV in numerous studies. These methods are free of side effects and represent therefore a good alternative to the pharmacological prophylaxis and treatment of PONV.

Rectally administered dimenhydrinate reduces postoperative vomiting in children after strabismus surgery.

We have investigated the effectiveness of rectally administered dimenhydrinate on postoperative vomiting in children undergoing strabismus surgery, in a double-blind, randomized, placebo-controlled study. In one group, dimenhydrinate 50 mg was administered rectally 30 min before starting anaesthesia, whereas in the control group, placebo suppositories were given. Children who received dimenhydrinate showed a significantly (P < 0.001) lower incidence of vomiting (15%) than those in the control group (75%). We conclude that rectal administration of dimenhydrinate is an effective means of reducing postoperative vomiting in children undergoing strabismus surgery.

Laser stimulation of acupuncture point P6 reduces postoperative vomiting in children undergoing strabismus surgery.

We conducted a double-blind, randomized, placebo-controlled study to investigate the effectiveness of P6 acupuncture on postoperative vomiting in children undergoing strabismus surgery. Acupuncture was performed by laser stimulation with a low-level laser. Laser stimulation of P6 was administered 15 min before induction of anaesthesia and 15 min after arriving in the recovery room. In the laser stimulation group, the incidence of vomiting was significantly lower (25%) than that in the placebo group (85%).

Korean hand acupressure reduces postoperative vomiting in children after strabismus surgery.

A double-blind, randomized, placebo-controlled study was conducted to investigate the effectiveness of Korean hand acupuncture in preventing postoperative vomiting in children scheduled for strabismus surgery. In one group, acupressure was performed 30 min before induction of anaesthesia by applying an acupressure disc onto the Korean hand acupuncture point K-K9; the disc remained in situ for at least 24 h. The second group functioned as placebo group. The treatment groups did not differ with regard to patient characteristics, surgical procedure and anaesthetic administered. In the acupressure group, the incidence of vomiting was significantly lower (20%) than in the placebo group (68%). We conclude that Korean hand acupressure of the acupuncture point K-K9 is an effective method for reducing postoperative vomiting in children after strabismus repair.

Transcutaneous CO2/O2 and CO2/air suction in patients undergoing cataract surgery with retrobulbar anaesthesia.

We investigated transcutaneous partial CO2 and O2 pressures and respiratory rate in unpremedicated elderly patients of ASA physical status 1 to 3 who underwent cataract surgery under retrobulbar anaesthesia. In group A no air suction was used. In group B suction was applied under the sterile drapes to avoid rebreathing of CO2. In group A transcutaneous partial CO2 pressure and respiratory rate significantly increased compared with baseline, whereas in group B they remained constant. In both groups transcutaneous partial O2 pressure and oxygen saturation as measured by pulse oximetry significantly rose after insufflating oxygen 31.min-1. Heart rate and mean arterial blood pressure remained constant. Our results demonstrate that the application of suction near the patient's head prevents CO2 rebreathing and subsequent hypercapnia associated with an elevated respiratory rate. The use of suction makes it unnecessary to raise oxygen administration. Suction combined with monitoring of partial CO2 pressure using transcutaneous sensors should be used in all ophthalmological operations under retrobulbar anaesthesia.

Prospective randomized trial using laser acupuncture versus desmopressin in the treatment of nocturnal enuresis.

OBJECTIVES: Several treatment modalities for children suffering from monosymptomatic nocturnal enuresis are available, but desmopressin is a well-established option. On the other hand, alternative nonpharmacological therapies such as laser acupuncture are more frequently requested by the parents. To our knowledge, there is no prospective randomized trial which evaluated the efficacy of such an alternative approach in comparison with the widespread use of desmopressin. METHODS: Forty children aged over 5 years presenting with primary nocturnal enuresis underwent a previous evaluation of their voiding function to assure normal voiding patterns and a high nighttime urine production. Then the children were randomized into two groups: group A children were treated with desmopressin alone, and group B children underwent laser acupuncture. All children were investigated after a minimum follow-up period of 6 month to evaluate the duration of the response. RESULTS: The children of both groups had an initial mean frequency of 5.5 wet nights per week. After a minimum follow-up period of 6 months reevaluation revealed a complete success rate of 75% in the desmopressin-treated group. Additional 10% of the children had a reduction of their wet nights of more than 50%. On the other hand, 6 months after laser acupuncture, 65% of the randomized children were completely dry. Another 10% had a reduction of the enuresis frequency of more than 50% per week. 20% of the children in the desmopressin-treated group did not respond at all as compared with 15% in the acupuncture-treated group. Statistical evaluation revealed no significant differences among the response rates in both groups. CONCLUSION: Im comparison with pharmacological therapy using desmopressin, our study shows that laser acupuncture should be taken into account as an alternative, noninvasive, painless, cost-effective, and short-term therapy for children with primary nocturnal enuresis in case of a normal bladder function and high nighttime urine production. Success rates indicated no statistically significant differences between the well-established desmopressin therapy and the alternative laser acupuncture.

Low-power laser light in the healing of burns: a comparison between two different wavelengths (635 nm and 690 nm) and a placebo group.

BACKGROUND AND OBJECTIVE: Studies on the influence of low-power laser light on wound healing have shown inconsistent results, or, as in the case of burns, are very scarce. We have studied the effects of two different low-power diode laser lights on the healing of burns in rats. STUDY DESIGN/MATERIALS AND METHODS: Thirty rats were burned on both flanks and randomly allocated to one of three study groups. In group A, both wounds remained untreated; in groups B and C, one wound each was irradiated with 635 nm or 690 nm laser light (1.5 J/cm(2)), whereas the other wound remained untreated. Diameter, redness, and edema of the wounds were examined daily. RESULTS: Between and within groups, diameter, redness, and edema of the wounds were similar throughout the entire observation period. Irradiation of the burns did not accelerate wound healing when compared with control wounds. CONCLUSION: We conclude that neither 690 nm nor 635 nm low-power laser light produced any beneficial effects on the healing processes of burns in rats.