Utility of nociceptive flexion reflex threshold and bispectral index to predict movement responses under propofol anaesthesia.

INTRODUCTION: The nociceptive flexion reflex threshold (NFRT) is a promising tool to monitor analgesia during general anaesthesia. Clinical studies have shown that the NFRT allows to predict movement responses to painful stimuli under a combined anaesthetic regime of sedative and opioid agents. Experimental studies indicated that the NFRT is also able to predict such movement responses under an exclusively sedative regime like propofol mono-anaesthesia. Therefore, we performed this study to investigate the ability of the NFRT to predict movement responses to painful stimuli in patients during a clinical propofol mono-anaesthesia. METHODS: We investigated 140 cardiac surgery patients during their postoperative phase under propofol mono-anaesthesia. NFRT and bispectral index (BIS) were determined in each patient right before endotracheal suctioning or painful electrical test stimulation. Prediction probabilities were calculated to quantify how accurate each measure is able to predict movement responses to the stimuli. RESULTS: The 124 patients included in the analysis received a median propofol dosage of 3.2 (2.5-3.9) [median (IQR)] mg/kg/h. The included patients showed 287 movement responses after a total of 725 investigated stimuli. The prediction probabilities for positive movement responses were 0.63 (95%CI: 0.59-0.67) for the NFRT and 0.69 (95%CI: 0.65-0.73) for the BIS. CONCLUSIONS: The NFRT allows the prediction of movement responses under propofol mono-anaesthesia, which confirms its utility as a monitor to predict movement responses under general anaesthesia. The BIS allows an even more accurate prediction, although it does not reflect the physiological structures of movement suppression, but correlates closely with the dose of propofol. TRIAL REGISTRATION: German clinical trial register (DRKS00003062, Deutsches Register Klinischer Studien).

Effects of sevoflurane and propofol on the nociceptive withdrawal reflex and on the H reflex.

BACKGROUND: The predominant target of anesthetics to suppress movement responses to noxious stimuli is located in the spinal cord. Although volatile anesthetics appear to produce immobility by actions on the ventral rather than the dorsal horn, the site of action of propofol remains unclear. METHODS: In a crossover design, the authors compared in 13 volunteers the effects of sevoflurane and propofol on the amplitudes of the H reflex, which is mediated exclusively in the ventral horn and a withdrawal reflex (RIII Reflex), which integrates dorsal and ventral horn function. The concentrations were adjusted according to a Dixon up-and-down approach, depending on movement responses to tetanic stimulation. RESULTS: Sevoflurane and propofol concentrations ranged from 1.2 to 1.6 Vol% and 3 to 6 mg/l, respectively. Sevoflurane reduced the H reflex amplitude significantly to 66 +/- 17% (mean +/- SD) of its control values. Propofol did not significantly reduce the H reflex. The reductions under the two drugs differed significantly. The RIII reflex amplitude was significantly reduced to 19 +/- 10% and 27 +/- 12% (mean +/- SD) of the control values by sevoflurane and propofol, respectively. The reductions did not differ between the drugs. CONCLUSIONS: Probably because of the polysynaptic relay, the attenuation of the withdrawal reflex exceeds the attenuation of the H reflex. Sevoflurane produces a larger inhibitory effect on the H reflex than propofol, which confirms that the ventral horn is a more important target for volatile anesthetics, whereas effects of propofol on this site of action are rather limited. Our findings indirectly suggest for propofol a relatively stronger effect within the dorsal horn.

Introduction of a continual RIII reflex threshold tracking algorithm.

INTRODUCTION: The RIII reflex is used in fundamental and clinical pain research. Here we introduce a continual reflex threshold tracking algorithm to facilitate investigations of the time courses of influences on the threshold. METHODS: First we investigated the probability of reflex occurrence at the threshold estimated by the continual algorithm and the changes of the threshold over the time during continual recordings of 100 min duration in 10 subjects. Secondly we compared the threshold estimates of the continual algorithm with those of a standard algorithm of threshold estimation in 52 subjects and compared the differences between the two methods with the test-retest-variability of each method. RESULTS: The average probability of reflex occurrence at the threshold estimated by the continual algorithm was 48.7% (SD = 3.2%). Changes of the RIII reflex threshold over the time were not significant (Friedman test, p>0.05). The variability between the thresholds determined by the different algorithms (test: SD = 2.50 mA, retest: SD = 1.80 mA) was lower than the variability between test and retest (standard algorithm: SD = 4.32 mA, continual algorithm: SD = 4.44 mA). DISCUSSION: The continual algorithm can be used for a continuous estimation of the reflex threshold at the 50% probability of reflex-occurrence. No evidence of habituation was detected. This allows for investigations of the time courses of pharmacological and physiological influences on the reflex threshold by using this algorithm. The lower variability between the continual algorithm and the standard algorithm compared to the variability between tests and retests of the methods allows for interchangeable conclusions drawn from data obtained with both methods.

Chemotherapy-induced dermatological toxicity: frequencies and impact on quality of life in women's cancers. Results of a prospective study.

PURPOSE: The study aimed to determine the prevalence of dermatological side effects and its impact on quality of life in patients receiving systemic chemotherapy for women's cancers. MATERIALS AND METHODS: A prospective study was conducted on patients with histologically confirmed advanced women's cancers who were deemed candidates for adjuvant or palliative chemotherapy. Patients were systemically examined for skin, hair, and nail side effects. The impact of those side effects on their quality of life was assessed using the health-related quality of life score (HRQL). RESULTS: Between April 2001 and October 2001, 91 patients received 1 to 17 (median 4) courses of chemotherapy. Malignancies included breast cancer (n = 39, 43%), ovarian cancer (n = 32, 35%), cervical cancer (n = 12, 13%), endometrial cancer (n = 5, 6%), fallopian tube cancer (n = 2, 2%), and vaginal cancer (n = 1, 1%). Chemotherapy agents included taxanes (n = 42, 46%), PEG doxorubicin (n = 17, 7%), other anthracyclines (epirubicin and doxorubicin; n = 6, 19%), topotecan (n = 13, 14%), and other agents (n = 13, 14%). Overall incidence of skin, nail, and hair side effects was 86.8% (n = 79). Seventeen patients (18.7%) developed a palmo-plantar erythrodysesthesia (PPE), and nine of those (53%) were of grade 3 in common toxicity criteria scale (NCI). Twenty-one patients (23.1%) developed nail changes such as subungual hematomas, onycholysis, and leukonychias or nail loss, while 69 (75.8%) developed hair loss. There was a higher incidence of PPE in patients receiving chemotherapy for palliation rather than cure (percent over percent, p < 0.001, Fisher's exact test). Using the HRQL score, skin changes were the most frequently reported unpleasant side effect (34.1%), and of those patients who developed PPE, this was reported by n = 8 (47%) as the most unpleasant. CONCLUSIONS: Dermatological chemotherapy side effects are frequent after treatment of women's cancers and have a major impact on quality of life as assessed by HRQL. Counseling of patients with women's cancers and the profile of side effects of chemotherapeutic agents should be considered before considering an adjuvant or palliative chemotherapy regimen.