[Therapeutic gases for newborns: recent developments and future perspectives]

In respiratory care some gases are generally used to support the ventilation. Though oxygen is the most frequently dispensed, other specialty gases has become common practice in the last years. This report reviews the literature concerning the four gases mainly utilized in Neonatal Intensive Care Unit (NICU). Inhaled Nitric oxyde is a selective pulmonary vasodilator largely employed in NICU, while the helium-oxygen mixture, also knows as heliox, is less common, although it is widely note both the capability of decrease the pressure and work of breathing necessary to ventilate the lung, and the improvement of gas exchange in particular clinical situations. Carbon dioxide is generally used in the management of a specific congenital heart defect, and xenon, already known for its aesthetic proprieties but rarely used, because of its neuroprotective effects, could play a role in neonatal hypoxia/ischemia syndrome.

CO(2) pneumoperitoneum prolongs survival in an animal model of peritonitis compared to laparotomy

BACKGROUND

The advantages of laparoscopic surgery have been well documented. However, the impact of pneumoperitoneum on sepsis sequelae is still equivocal. This study aimed to evaluate the effect of CO(2) pneumoperitoneum, applied under different pressures and exposure times, on sepsis cascade and mortality.

MATERIAL AND METHODS

In 42 New Zealand rabbits, peritonitis was induced by the cecum ligation and puncture model. After 12 h, the animals were randomized in seven groups: a control group, four groups with pneumoperitoneum (10-15 mmHg for 60-180 min), and two groups with laparotomy (for 60 and 180 min). Blood samples were collected before cecum ligation and puncture, 12 h later and 1, 3, and 6 h after pneumoperitoneum desufflation or abdominal trauma closure to evaluate bacteremia, endotoxemia, white blood cells count, C-reactive protein, and procalcitonin levels. Furthermore, the mortality time was recorded in all animals.

RESULTS

Bacteremia and endotoxemia were induced in all groups. Endotoxemia levels were significantly more elevated in the group where pneumoperitoneum was performed under 15 mmHg for 180 min compared with all other groups at 1 and 3 h after pneumoperitoneum desufflation (P < 0.05), except when compared with the group where pneumoperitoneum was performed under 10 mmHg for 180 min. White blood cell and C-reactive protein levels showed similar trends for all groups. However, serum procalcitonin reached statistically higher levels (P < 0.05) in groups with laparotomy compared with groups with pneumoperitoneum and with the control group at 6 h. Survival was lower in the laparotomy groups compared with the pneumoperitoneum groups and with the control group (P < 0.05).

CONCLUSIONS

In the presence of peritonitis, CO(2) pneumoperitoneum applied in clinically standard pressures, even for extended time intervals, reduces the severity of sepsis and prolongs survival.

Thermal protection during percutaneous thermal ablation procedures: interest of carbon dioxide dissection and temperature monitoring

Percutaneous image-guided thermal ablation of tumor is widely used, and thermal injury to collateral structures is a known complication of this technique. To avoid thermal damage to surrounding structures, several protection techniques have been reported. We report the use of a simple and effective protective technique combining carbon dioxide dissection and thermocouple: CO(2) displaces the nontarget structures, and its low thermal conductivity provides excellent insulation; insertion of a thermocouple in contact with vulnerable structures achieves continuous thermal monitoring. We performed percutaneous thermal ablation of 37 tumors in 35 patients (4 laser, 10 radiofrequency, and 23 cryoablations) with protection of adjacent vulnerable structures by using CO(2) dissection combined with continuous thermal monitoring with thermocouple. Tumor locations were various (19 intra-abdominal tumors including 4 livers and 9 kidneys, 18 musculoskeletal tumors including 11 spinal tumors). CO(2) volume ranged from 10 ml (epidural space) to 1500 ml (abdominal). Repeated insufflations were performed if necessary, depending on the information given by the thermocouple and imaging control. Dissection with optimal thermal protection was achieved in all cases except two patients where adherences (one postoperative, one arachnoiditis) blocked proper gaseous distribution. No complication referred to this technique was noted. This safe, cost-effective, and simple method increases the safety and the success rate of percutaneous thermal ablation procedures. It also offers the potential to increase the number of tumors that can be treated via a percutaneous approach.

[The influence of "dry" bi-carbonate baths on the circadian profile of arterial pressure in patients who suffered acute myocardial infarction]

The objective of this study was to evaluate effect of "dry" bi-carbonate baths (DBB) on the circadian profile of arterial pressure (AP) in patients who suffered acute myocardial infarction (AMI). Diurnal AP profiles were analysed in all patients after AMI. The patients comprising group 1 were treated with the use of DBB while the remaining ones received a sham treatment. 24 hour AP monitoring was performed before and after therapy. The study revealed a reduction in the frequency of hypotensive diastolic values at the daytime and in the duration of night-time hypertensive episodes under the influence of therapy with the use of DBB. Variability of systolic AP throughout 24 hours and of diastolic AP at daytime also decreased. Generally speaking, patients with elevated AP showed a more pronounced effect of DBB on the night AP profile. It is concluded that therapy with the use of DBB after AMI has beneficial effect on the clinical state of the patients and reduces the risk of cardiovascular complications.

[The effects of carbogen inhalation on microvascular within lateral wall of cochlear following acute acoustic trauma]

OBJECTIVE

To explore the influence of carbogen on lateral wall microvascular of cochlear after acute acoustic trauma.

METHOD

Forty guinea pigs were divided into 4 groups: group A (noise damage), group B (carbogen inhalation), group C (noise damage + carbogen inhalation), and the control group without any treatment. The diameter of the column of RBCs (RBC column diameter, RBCCD), blood flow velocity (BFV) and blood flow states(BFS) in microvasculature were measured and described under microscope.

RESULT

The microvascular in group A demonstrated a blood flow in contrary direction, granuliform flow, and granular slow flow. The erythrocytes aggregated in the microvascular of the cochlea. The RBCCD decreased 12.1% compared with the control group (P < 0.05). The blood flow in group B showed a laminar flow or laminar granular flow, and the RBCCD increased 20.7% compared with the control group. The blood condition in group C was the same as the control group-laminar granular blood flow; the blood flow with contrary direction was less than group A, and the RBCCD was 17.4% lager than that of group A.

CONCLUSION

Carbogen can dilate the RBCCD and increase the BFV in stria vascular. So carbogen can alleviate the harm from noise.

CO2 laser desiccation of urethral hair post-penoscrotal hypospadias repair

BACKGROUND

Proximal urethral defects account for approximately 20% of hypospadiac urethras. Previous surgical interventions involved hair-bearing genital skin which consequently resulted in a hairy urethra, which is seen mainly in older patients.

OBJECTIVE

To evaluate the safety and effectiveness of the CO2 laser for urethra hair elimination.

METHODS

Four men aged 18-20 years with hairy urethras, who failed electrolysis treatment, were treated with CO2 laser desiccation at low fluences (2-5 watts). The treatments were performed at 1-month intervals. Treatment was continued until no hair was seen. Visual assessment of the hair reduction was recorded.

RESULTS

Patients received two to four treatment sessions (average 3.2). On clinical assessment 3 months after the last treatment, outcome was rated excellent (no hair) in all patients.

CONCLUSIONS

CO2 laser desiccation should be considered as a therapeutic modality for a hairy urethra, especially after the failure of electrolysis.

Safety and utility of uterine artery embolization with CO2 and a gadolinium-based contrast medium

The authors evaluated the safety and clinical outcomes of uterine artery embolization (UAE) without the use of conventional iodinated contrast media for symptomatic uterine leiomyomata. Patients underwent UAE with use of CO(2) gas and a gadolinium-based contrast medium. The safety and feasibility of the technique were assessed. Patients were followed up at 24 hours, 1 month, and 6 months after UAE and yearly thereafter. UAE without iodinated contrast medium was attempted in eight patients (mean age, 42.7 years +/- 4.1), and bilateral UAE was successful in all patients. The mean fluoroscopy time was 14.9 minutes. The mean amount of gadolinium-based contrast medium used was 30.6 mL or 0.181 mmol/kg. No major complications were noted. The mean improvement in the symptom severity score was 53.8. The mean reduction in leiomyoma volume was 42%. To date, no repeat interventions have been performed. UAE with CO(2) and a gadolinium-based contrast medium is a viable treatment option for patients with a severe allergy to iodinated contrast media or renal insufficiency.

Hyperthermic CO2 pneumoperitoneum induces apoptosis in human colon cancer cells through Bax-associated mitochondrial pathway

Peritoneal carcinomatosis of colorectal cancer is common and associated with poor prognosis, which poses a serious challenge and satisfactory treatments are urgently needed. Hyperthermic CO2 pneumoperitoneum (HT-CO2) is a new strategy. This study was designed to determine the potential of HT-CO2 against colorectal cancer cells. Based on an in vitro HT-CO2 study model, the anti-tumor efficacy of HT-CO2 (42-44 degrees C for 2-4 h) on human colon cancer COLO 205 cells was evaluated and the mechanisms of actions were analyzed. We found that HT-CO2 (43-44 degrees C for 2-4 h) significantly decreased cell viability as determined by WST-8 assay, and the cytotoxicity was attributable to HT-CO2-induced hyperthermia and extracellular acidification. Apoptosis was the major form of cell killing as demonstrated by Annexin-V/PI flow cytometry and morphological analysis (Hoechst/PI fluorescence microscopy and transmission electron microscopy). Further Western blot analysis and flow cytometric analysis of mitochondrial membrane potential showed that Bax-associated mitochondrial apoptotic pathway played critical role in the induction of apoptosis. We conclude that HT-CO2 has significant cytotoxic effect on colon cancer cells through induction of Bax-associated mitochondrial apoptosis, and the cytocidal effect is attributable to HT-CO2-induced hyperthermia and extracellular acidifications. Our data suggest that HT-CO2 may serve as a potential candidate for treating and/or preventing peritoneal carcinomatosis of colorectal cancer and further investigations both in vitro as well as in vivo in animal models are needed.

Comparison of depth of necrosis achieved by CO2- and N2O-cryotherapy

OBJECTIVE

To compare the depth of necrosis achieved using CO2- and N2O-cryotherapy.

METHOD

We treated 20 women with CO2-cryotherapy and 20 with N2O-cryotherapy 24 h prior to undergoing total hysterectomy for reasons unrelated to cervical cancer. Depth of necrosis in the ectocervix was measured on surgically removed tissue.

RESULTS

The mean depth of necrosis for the anterior lip achieved by N2O-cryotherapy was 5.3 mm compared with 3.4 mm by CO2-cryotherapy (P<0.001). We found similar results for the posterior lip (5.0 vs 3.1 mm; P<0.001). N2O-cryotherapy was more likely than CO2-cryotherapy to achieve a depth of necrosis of >or=4.8 mm for the anterior lip (75% vs 15%; P<0.001) and posterior lip (60% vs 5%; P<0.001).

CONCLUSIONS

Our study showed that CO2-cryotherapy may not achieve the depth of necrosis necessary to completely destroy cervical precancer and therefore may be less robust than N2O-cryotherapy.

Voice function following CO2 laser microsurgery for precancerous and early-stage glottic carcinoma

CONCLUSIONS

With the cover layer injured, vocal function of mucosal ablation could be protected and even return to normal after surgery and vocal function of mucosal stripping was slightly affected with extensive mucosal injury. Once the body layer was injured, the compensatory mechanism would play an important role in phonation.

OBJECTIVES

To investigate voice function following CO2 laser microsurgery for precancerous and early-stage glottic carcinoma.

PATIENTS AND METHODS

Vocal function was examined by acoustic analysis, aerodynamic analysis and videostroboscopic examination.

RESULTS

For mucosal ablation, vocal quality recovered 1 month after surgery. For mucosal stripping, although vocal quality was steady 3 months after surgery, slight hoarseness persisted in this group. The contour of the treated fold recovered postoperatively. There were no complications in recovery. For cordectomies, vocal quality became steady 6 months after the surgery. The supraglottal hyperfunction with supraglottal structure squeezing played an important role in phonation. The affected vocal fold mucosal wave was absent instead of a regular ventricular fold wave or mucosal wave of the vocal process during phonation. In comparison with the type III-IV cordectomy, the results of extended cordectomies (type Va and Vc) were worse; however, the difference was not statistically significant. Granulomas and anterior commissure webs were present. All granulomas resolved spontaneously 3 months postoperatively.

The hypoxic tumour microenvironment, patient selection and hypoxia-modifying treatments

Tumour hypoxia has been found to be a characteristic feature in many solid tumours. It has been shown to decrease the therapeutic efficacy of radiation treatment, surgery and some forms of chemotherapy. Successful approaches have been developed to counteract this resistance mechanism, although usually at the cost of increased short- and long-term side-effects. New methods for qualitative and quantitative assessment of tumour oxygenation have made it possible to establish the prognostic significance of tumour hypoxia. The ability to determine the degree and extent of hypoxia in solid tumours is not only important prognostically, but also in the selection of patients for hypoxia-modifying treatments. To provide the best attainable quality of life for individual patients it is of increasing importance that tools be developed that allow a better selection of patients for these intensified treatment strategies. Several genes and proteins involved in the response to hypoxia have been identified as potential candidates for future use in predictive assays. Although some markers and combinations have shown potential benefit and are associated with treatment outcome, their clinical usefulness needs to be validated in prospective trials. A review of published studies was carried out, focusing on the assessment of tumour hypoxia, patient selection and the possibilities to overcome hypoxia during treatment.

Combined effects of carbon dioxide laser and fluoride on demineralized primary enamel: an in vitro study

This in vitro study aimed at evaluating the efficacy of a CO(2) laser (10.6 microm) alone or combined with acidulated phosphate fluoride (APF) on the inhibition of lesion progression in primary enamel. The specimens were treated with/without CO(2) laser and/or APF and submitted to pH cycling. Microhardness analysis was performed and the enamel mineral loss values were obtained. The groups treated with laser and/or APF presented lower mineral loss when compared to the control group (p < 0.05). Laser irradiation alone or combined with APF decreased lesion progression in primary enamel. However, the combined treatment did not show any significant additional effect.

Paediatric granular cell tumour of the larynx: case report of laser resection with frozen section

Granular cell tumours of the larynx are a very rare cause of persistent hoarse or husky voice in children. We report the case of a 13-year-old girl who presented with a three-year history of progressively huskier voice. We discuss the presentation, location and diagnosis of the tumour. In addition, we present a method of surgical treatment of the tumour, involving the hitherto unreported technique of laser excision and frozen section of the lesion.

Long-term benefit of radon spa therapy in the rehabilitation of rheumatoid arthritis: a randomised, double-blinded trial

This study investigates the effects of radon (plus CO2) baths on RA in contrast to artificial CO2 baths in RA rehabilitation using a double-blinded trial enrolling 134 randomised patients of an in-patient rehabilitative programme (further 73 consecutive non-randomised patients are not reported here). The outcomes were limitations in occupational context/daily living (main outcome), pain, medication and further quantities. These were measured before the start, after the end of treatment and quarterly in the year thereafter. Repeated-measures analysis of covariance (RM-ANCOVA) of the intent-to-treat population was performed with group main effects (GME) and group x course interactions (G x C) reported. Hierarchically ordered hypotheses ensured the adherence of the nominal significance level. The superiority of the radon treatment was found regarding the main outcome (RM-ANCOVA until 12 months: p(GME) = 0.15, p(G x C) = 0.033). Consumption of steroids (p(GME) = 0.064, p(G x C) = 0.025) and NSAIDs (p(GME) = 0.035, p(G x C) = 0.008) were significantly reduced. The results suggest beneficial long-term effects of radon baths as adjunct to a multimodal rehabilitative treatment of RA.

Carbon dioxide insufflation for more comfortable endoscopic retrograde cholangiopancreatography: a randomized, controlled, double-blind trial

BACKGROUND AND STUDY AIMS

The effect on abdominal pain of using carbon dioxide (CO2) for insufflation during endoscopic retrograde cholangiopancreatography (ERCP) has not been investigated. The present study aimed to compare CO2 insufflation with standard air insufflation with respect to the pain experienced during and after ERCP. In addition, we investigated the effect of CO2 insufflation on the partial pressure of CO2 (Pco2).

PATIENTS AND METHODS

A total of 118 consecutive patients who were undergoing ERCP were randomized to CO2 insufflation or to air insufflation during the procedure. Both the endoscopists and the patients were blinded with regard to the gas used. Patients rated the intensity of pain experienced on a 100-mm visual analogue scale (VAS) during ERCP and at 1 hour, 3 hours, 6 hours, and 24 hours after the procedure. Transdermal Pco2 was measured continuously in all patients during the procedure.

RESULTS

Altogether, 116 patients were eligible for analysis, 58 in each treatment group, and 91 patients responded to the questionnaire (78 %). The mean severity of postprocedure pain was significantly reduced in the CO2 group compared with the air group at 1 hour (5 mm vs. 19 mm on the VAS, P < 0.001), at 3 hours (7 mm vs. 21 mm, P < 0.001), at 6 hours (10 mm vs. 22 mm, P = 0.006), and at 24 hours (4 mm vs. 20 mm, P < 0.001) after the procedure. Radiographs taken 5 minutes after the procedure showed that abdominal distension was more pronounced in patients in the air insufflation group. There were no differences in Pco2values between the two treatment groups.

CONCLUSIONS

Carbon dioxide insufflation during ERCP significantly reduces postprocedural abdominal pain. No side effects were observed. Carbon dioxide should be the standard gas used for insufflation in ERCP.

Management of a severe forceful breather with Rett syndrome using carbogen

We have used a novel neurophysiological technique in the NeuroScope system in combination with conventional electroencephalography (EEG) to monitor both brainstem and cortical activity simultaneously in real-time in a girl with Rett syndrome. The presenting clinical features in our patient were severe sleep disturbances, irregular breathing in the awake state dominated by Valsalva's type of breathing followed by tachypnoea and very frequent attacks of seizures and vacant spells. Our novel neurophysiological data showed that the patient was a Forceful Breather according to the breathing categories in Rett syndrome. She had frequent abnormal spontaneous brainstem activation (ASBA) preceded by severe attacks of hypocapnoea, which was caused by a combination of Valsalva's type of breathing and tachypnoea and all these together were responsible for the seizures and non-epileptic vacant spells. The ASBA was not detectable in conventional EEG and there were no epileptiform changes in the EEG during the seizures and vacant spells caused by the hypocapnic attacks, therefore these were pseudo-seizures. The record of brainstem activity confirmed that these were autonomic events, a kind of "brainstem epilepsy". We successfully treated the sleep disturbance with Pipamperone, a 5-hydroxytryptophan antagonist of receptor type 2 and we prevented the severe hypocapnoea during Valsalva's type of breathing and during tachypnoea using carbogen (a mixture of 5% carbon dioxide and 95% oxygen), which we gave by inhalation. Our treatment drastically reduced the autonomic events, promoted whole night sleep and significantly improved the quality of life in our patient. She can now participate in normal family activity which was previously impossible before treatment.

CO2 laser treatment of laryngeal stenoses after reconstructive laryngectomies with cricohyoidopexy, cricohyoidoepiglottopexy or tracheohyoidoepiglottopexy

Supracricoid laryngectomy with cricohyoidopexy (CHP) or cricohyoidoepiglottopexy (CHEP) is a conservative laryngeal surgery tailored to T1b-T2-T3 glottic-supraglottic carcinomas. Tracheohyoidopexy (THP) and tracheohyoidoepiglottopexy (THEP) allow a chance of conservative surgery also for selected transglottic carcinomas. These techniques are comprehensively named reconstructive laryngectomies (RLs). Post RL laryngeal stenosis not due to carcinoma persistence or recurrence is an unusual occurrence. The aim of the present study has been to analyse retrospectively and describe the treatment of the cases of laryngeal stenosis after RL, which occurred in Vittorio Veneto Otolaryngological Department in a 6 year period. In the period between 1999 and 2004, 225 patients underwent RL in our Department. In 18 of them (8%) a laryngeal stenosis after RL was diagnosed. The same evidence was shown in 2 patients who underwent RL in other Institutions. All patients underwent CO(2) laser surgical treatment of the laryngeal stenosis. The 14 patients who underwent RL-CHEP, the 5 patients who underwent THEP and the patient who underwent CHP were treated on average with CO(2) laser 1.2 (range 1-2), 4.2 (range 2-7), and 2 times, respectively. Decannulation was possible in all patients but one after CO(2) laser treatment of the stenosis in a mean period of 3.4 months. Laryngeal stenoses after RLs can be successfully treated with CO(2) laser excision with a very limited morbility. The only reasonable contra-indication to CO(2) laser excision could be a cranio-caudal length of the laryngeal stenotic tract longer than 1 cm: in this occurrence diagnosed after THP or THEP, an external surgical approach could be preferred.

Alleviation of intracranial air using carbon dioxide gas during intraventricular tumor resection

OBJECTIVES/PURPOSES

Postoperative vomiting occurs more frequently in patients after intraventricular surgery than after other intracranial surgeries. This has been attributed to intracranial air. Carbon dioxide gas (CO2) has properties beneficial to the treatment of some medical disorders, displaying a higher specific gravity and more rapid absorption into surrounding tissues than air. We therefore, attempted to replace air with CO2 during intra- and paraventricular tumor resections. The aim of the present study was to elucidate whether intracranial air after intraventricular surgery could be alleviated safely using CO2, and investigate its clinical usefulness.

PATIENTS AND METHODS

CO2 was introduced into the subdural space at 2l/min through a silicon tube from time of dural incision to closure. Subjects comprised 40 patients alternately assigned to one of two groups: the trial group (n=20) receiving CO2 treatment; and controls (n=20) without CO2 treatment.

RESULTS

Intra- and postoperatively, no patients showed complications caused by CO2 treatment. Postoperatively, intraventricular gas shown on CT scans disappeared significantly sooner in the trial group than in controls. Frequency of postoperative vomiting was significantly lower in the trial group than in controls.

CONCLUSION

Intracranial air after intraventricular surgery can be safety alleviated using CO2.

Controlling thermal damage of incisions using diamond, copper, and sapphire heat-conducting templates with and without cooling

INTRODUCTION

We investigated the reduction of thermal damage to the surrounding tissue when laser incisions were made with and without using thermal conducting templates at room temperature and cooled to 5 degrees C.

STUDY DESIGN/MATERIALS AND METHODS

We used the Vanderbilt free-electron laser (FEL) at 5.4, 6.1, 6.45, and 7.7 microns. We also used a conventional continuous wave (CW) carbon dioxide laser at 10.6 microns. Incisions were made on 5x10 mm pieces of human breast skin (in vitro) and analyzed with histology. Computer morphometrics were used to measure the amount of thermal damage.

RESULTS

All templates produced a statistically significant reduction in the thermal damage. Additionally, we showed that cooling the templates made a statistically significant greater reduction in the thermal damage. The cooled diamond template reduced the thermal damage from the FEL to 28% of the damage observed without a template. The same cooled template reduced the thermal damage from the CO(2) laser to 56% of the damage observed without a template. Lesser reductions were observed with the copper template and even less with the sapphire template. The sapphire template reduced the thermal damage to 39 and 67% of the damage observed without a template for the FEL and the CO(2) laser, respectively.

CONCLUSION

These results indicate that unwanted lateral thermal damage from laser incisions can be reduced with cooled thermally conductive templates with the best results obtained with the diamond template, which is also the best thermal conductor.