Effects of different forms of dyspnoea on pain perception induced by cold-pressor test.

Although dyspnoea has been shown to attenuate pain, whether different forms of dyspnoea exert a similar inhibitory effect on pain has never been tested. We examined the effects of two different forms of dyspnoea, i.e., "air hunger" sensation (AIR HUNGER) and "work/effort" sensation (WORK/EFFORT), on pain induced by a cold-pressor test. Dyspnoea was induced by two different dyspnoea stimuli (i.e., AIR HUNGER and WORK/EFFORT stimuli) and the magnitudes of both sensations were evaluated by using a visual analogue scale (VAS). At equi-dyspneic VAS levels of two different forms of dyspnoea, pain was induced and the unpleasantness of pain was assessed by pain VAS, pain threshold time (PTT) and pain endurance time (PET). Both AIR HUNGER and WORK/EFFORT caused an increase in PTT and an increase in PET or a decrease in maximal pain VAS. Our findings suggest that AIR HUNGER and WORK/EFFORT exert a similar analgesic effect although the WORK/EFFORT-induced analgesia was slightly more effective.

Patient-reported usefulness of peripherally inserted central venous catheters in terminally ill cancer patients.

CONTEXT: Oral administration of medication is often difficult in terminally ill cancer patients, and a subcutaneous route is traditionally one of the most preferred parenteral routes. Recent studies suggest, however, that some patients and families prefer the intravenous route, and peripherally inserted central venous catheters (PICCs) are actively used in oncology settings. Nonetheless, in the palliative care setting, no empirical studies have investigated the patient-perceived usefulness of PICCs. OBJECTIVES: The primary aim of this prospective observational study was to clarify the levels of patient-perceived comfort and convenience, in addition to procedure-related distress, resulting from the use of PICCs by terminally ill cancer patients. RESULTS: Among 219 patients admitted to a palliative care unit during the one-year study period, 39 (18%) patients underwent a PICC insertion trial (a total of 44 procedures were performed because five patients underwent PICC insertion twice). Of the 44 procedures, 38 (86%) were successful, requiring a mean of 23+/-7.9 minutes, without serious procedure-related complications. Patient-reported levels of procedure-related distress were not distressing (68%), slightly distressing (8%), and distressing (24%). Patient-reported comfort levels with parenteral access were becoming more comfortable (94%) and no change (6%). Patient-reported convenience levels of parenteral access were becoming more convenient (94%) and no change (6%). Complications were reversible catheter coagulation (10%), irreversible catheter coagulation (8%), and mild levels of edema of the upper extremity (8%). The PICCs remained in place in 82% of the patients until death. The median period of placement was 15 days, with the longest placement being 81 days. CONCLUSION: PICCs were safely inserted in about 90% of terminally ill cancer patients within about 20 minutes. Although 30% of the patients experienced transient mild procedure-related distress, more than 90% of the patients felt that the parenteral route was more comfortable and convenient after the procedure. PICCs may provide a safe, comfortable, and convenient alternative for terminally ill cancer patients, if placement of the PICC is individualized to the patient situation and after alternatives are considered. Further studies are needed to compare the superiority of the PICC and traditional subcutaneous route to clarify what types of patients are the most suitable for each procedure.

Comparison of pain and dyspnea perceptual responses in healthy subjects.

Dyspnea and pain have a number of similarities. Recent brain imaging experiments showed that similar cortical regions are activated by the perceptions of dyspnea and pain. We tested the hypothesis that an individual's pain sensitivity might parallel the individual's dyspnea sensitivity. Studies were carried out in 52 young healthy subjects. Each subject experienced experimentally induced pain and dyspnea. Pain was induced by a cold-pressor test and dyspnea was induced by breathholding while the unpleasant experience of pain and dyspnea was assessed by using a Visual Analogue Scale (VAS). The times from the start of cold stimulation and breathholding to the onset of uncomfortable sensation (pain threshold time and the period of no respiratory sensation, respectively) and to the limit of tolerance (pain endurance time and total breathholding time, respectively) were also measured. In response to cold pain stimulation, a behavioral dichotomy (pain-tolerant and pain-sensitive) was observed. The period of no respiratory sensation was significantly shorter in the PS (pain-sensitive) group than in the PT (pain-tolerant) group (16.9+/-3.8 vs. 19.6+/-5.3 s: P<0.05), whereas no significant difference in the total breathholding time was found between the PT and PS groups. A significant correlation was observed between the pain threshold time and the period of no respiratory sensation in both the PT and PS groups. However, no significant association was observed between pain and dyspnea tolerance in both groups. In conclusion, an individual's pain threshold is correlated to the individual's dyspnea threshold, but the individual's pain tolerance is not consistently correlated to the individual's dyspnea tolerance.