Cooling treatment on the reduction of category II fetal tracings

OBJECTIVES

Epidural-related maternal fever increases the incidence of Category II fetal tracings. To compare the effectiveness of low-flow oxygen inhalation and cooling treatment for parturients with Category II fetal tracings caused by epidural-related maternal fever.

METHODS

We investigated 200 pregnant women who accepted epidural analgesia during labor and had body temperature exceeding 38 °C during labor. Among the patients, 99 and 101 were randomly allocated to receive cooling treatment group (control group) and oxygen inhalation (oxygen group), respectively. The primary outcome was the incidence of Category II fetal heart rate tracings.

RESULTS

The incidence of Category II fetal heart rate tracings in the control group was significantly higher than that in the oxygen group. However, no significant differences were noted between the two groups in terms of the Apgar scores; amniotic fluid turbidity; or maternal outcomes, including cesarean section rate, forceps delivery rate, lateral resection rate, manual removal of placenta rate, the amount of intrapartum hemorrhage, and hemorrhage at postpartum 2 h. Oxygen inhalation therapy was more effective than cooling treatment in reducing the incidence of Category II tracings.

CONCLUSION

Low-flow and short-term oxygen inhalation for parturients with epidural-related maternal fever reduces the incidence of Category II fetal heart rate tracings, but had no significant influence on the mode of delivery or neonatal outcomes.

Oxygen inhalation has no effect on provoked cranial autonomic symptoms using kinetic oscillation stimulation in healthy volunteers

OBJECTIVE

Inhalation of oxygen is highly effective in cluster headache, a subtype of trigeminal autonomic cephalgias. Since oxygen has no effect on nociceptive pain, the mechanism of action is still unknown. The present study investigated whether oxygen inhalation modifies the trigeminal autonomic reflex arc in healthy volunteers.

METHODS

21 healthy volunteers participated in a randomized, placebo controlled, double-blind, cross-over, and within-subject study design. In a randomized order demand valve inhalation of 100% oxygen or medical air were administered. Capillary blood samples were collected to control for blood gas changes. Cranial parasympathetic output (lacrimation) was provoked using kinetic oscillation stimulation of the nasal mucosa. Standardized measurement of lacrimation between baseline and kinetic oscillation stimulation served as a measure of induced cranial autonomic output.

RESULTS

There was no significant difference in parasympathetic output after oxygen inhalation when compared to inhalation of medical air.

CONCLUSION

The inhalation of 100% oxygen does not affect the parasympathetic reflex arc of the trigeminal autonomic reflex.

Oropharyngeal Oxygen Concentration Is Dependent on the Oxygen Mask System and Sampling Location

BACKGROUND

Numerous oxygen delivery systems are used to treat hypoxemia. It is unknown if F_IO2 at the lips predicts oropharyngeal F_IO2 for various oxygen mask systems. We tested whether F_IO2 measurements differed between the lips and oropharynx, and whether this difference depends on the mask system.

METHODS

Ten healthy volunteers had one sampling catheter positioned at the lips and another catheter in the oropharynx. F_IO2 was sampled at each location while the subjects breathed normal tidal volumes with oxygen at 15 L/min via 4 delivery devices: a simple mask, a non-rebreather mask, a face mask with a diffuser that concentrates and directs O₂ toward the mouth and nose (mask with diffuser), and a closed mask with a Jackson-Rees circuit. Data were analyzed by using a linear mixed model to account for subject crossover in the repeated measures design.

RESULTS

F_IO2 levels differed significantly for the 4 delivery mask systems (P < .001) and by sampling catheter location (P < .001). Differences in mean F_IO2 between the lips and the oropharynx were observed for the mask with diffuser (difference 0.30, 95% CI 0.25-0.36; P < .001), and non-rebreather mask (difference 0.09, 95% CI 0.04-0.15; P = .001). The mean F_IO2 at the oropharynx was highest for the closed mask (0.97, 95% CI 0.92-1.00), followed by the non-rebreather mask (0.76, 95% CI 0.72-0.81), simple mask (0.62, 95% CI 0.58-0.67), and the mask with diffuser (0.51, 95% CI 0.46-0.56). At the lips, the mean F_IO2 was highest for the closed mask (0.97, 95% CI 0.92-1.00), followed by the non-rebreather mask (0.86, 95% CI 0.81- 0.90), OxyMask (0.81, 95% CI 0.76-0.86), and simple mask (0.67, 95% CI 0.62-0.71).

CONCLUSIONS

With high oxygen flows and normal tidal volume breathing, F_IO2 measurements obtained at the oropharynx or at the lips depended on the device used, with the mask with diffuser showing the most significant discrepancies. F_IO2 measures at the oropharynx and the lips were only consistent for the closed mask system. (ClinicalTrials.gov registration NCT02523586.).

Humidification of Blow-By Oxygen During Recovery of Postoperative Pediatric Patients: One Unit's Journey

PURPOSE

To examine the practice of nebulizer cool mist blow-by oxygen administered to spontaneously breathing postanesthesia care unit (PACU) pediatric patients during Phase one recovery.

DESIGN

Existing evidence was evaluated. Informal benchmarking documented practices in peer organizations. An in vitro study was then conducted to simulate clinical practice and determine depth and amount of airway humidity delivery with blow-by oxygen.

METHODS

Informal benchmarking information was obtained by telephone interview. Using a three-dimensional printed simulation model of the head connected to a breathing lung simulator, depth and amount of moisture delivery in the respiratory tree were measured.

FINDINGS

Evidence specific to PACU administration of cool mist blow-by oxygen was limited. Informal benchmarking revealed that routine cool mist oxygenated blow-by administration was not widely practiced. The laboratory experiment revealed minimal moisture reaching the mid-tracheal area of the simulated airway model.

CONCLUSIONS

Routine use of oxygenated cool mist in spontaneously breathing pediatric PACU patients is not supported.

Conspicuous effect on treatment of mild-to-moderate COPD by combining deep-breathing exercise with oxygen inhalation

Chronic obstructive pulmonary disease (COPD) can lead to respiratory failure, but current pharmacological treatments focus on symptom relief or slowing disease progression. Here, the effectiveness of an alternative therapy combining deep-breathing exercises and oxygen inhalation therapy was assessed in mild-to-moderate COPD patients. Forty-two male mild-to-moderate COPD patients were randomly divided into a deep-breathing training group, an oxygen inhalation group, and a combination group (n=14 in each). In the deep-breathing training group, the patients were treated only by the deep-breathing exercise; in the oxygen inhalation group, the patients were treated only by oxygen inhalation; in the combination group, the patients were treated by combining the deep-breathing exercises with oxygen inhalation. Before treatment, there were no statistical differences in the general characteristics or lung function indexes between the three groups of patients (P > 0.05). However, after treatment, patients in the combination group had significantly better lung function indexes than they did before treatment, and their improvement was also superior to that of patients from the deep-breathing training group and the oxygen inhalation group (P < 0.01 and P < 0.05, respectively). Thus, a treatment method combining deep-breathing exercise with oxygen inhalation offers more significant lung function improvement in COPD patients than either the deep-breathing exercise or oxygen inhalation alone. This approach should be further explored for use in the clinic.

Temporal retinal nerve fibre layer thinning in cluster headache patients detected by optical coherence tomography

BACKGROUND

The exact pathophysiology of cluster headache (CH) is still not fully clarified. Various studies confirmed changes in ocular blood flow during CH attacks. Furthermore, vasoconstricting medication influences blood supply to the eye. We investigated the retina of CH patients for structural retinal alterations with optical coherence tomography (OCT), and how these changes correlate to headache characteristics, oxygen use and impaired visual function.

METHODS

Spectral domain OCT of 107 CH patients - 67 episodic, 35 chronic, five former chronic sufferers - were compared to OCT from 65 healthy individuals. Visual function tests with Sloan charts and a substantial ophthalmologic examination were engaged.

RESULTS

Reduction of temporal and temporal-inferior retinal nerve fibre layer (RNFL) thickness was found in both eyes for CH patients with a predominant thinning on the headache side in the temporal-inferior area. Chronic CH patients revealed thinning of the macula compared to episodic suffers and healthy individuals. Bilateral thinning of temporal RNFL was also found in users of 100% oxygen compared to non-users and healthy controls. Visual function did not differ between patients and controls.

DISCUSSION

Our OCT findings show a systemic effect causing temporal retinal thinning in both eyes of CH patients possibly due to attack-inherent or medication-induced frequent bilateral vessel diameter changes. The temporal retina with its thinly myelinated parvo-cellular axons and its more susceptible vessels for the vasoconstricting influence of oxygen inhalation seems to be predisposed for tissue damage-causing processes related to CH.