Once-daily gentamicin dosing for the preterm and term newborn: proposal for a simple regimen that achieves target levels.

OBJECTIVE: Based on recent safety and efficacy data, combined with the known pharmacokinetic parameters of aminoglycosides in the newborn, once-daily gentamicin should be preferable to the many other dosing regimens currently in use. Although there are growing data to support its use in term newborns, experience with preterm infants is more limited. In our Neonatal Intensive Care Unit, we experienced difficulties regarding complicated dosing regimens, actual dosing errors, and the tendency to check trough and peak levels around the third dose for infants receiving only a 48 hour course. Therefore, we conducted a quality improvement initiative in which we developed and tested a clinical practice guideline for the use of once-daily gentamicin for preterm and term infants that we hoped would yield trough and peak levels in our target range. METHODS: We combined a review of the published English language literature with pharmacokinetic analysis of our own data prior to initiation of this new regimen to design the following dosing regimen: <35 weeks gestation: 3 mg/kg q 24 hours, > or =35 weeks gestation: 4 mg/kg q 24 hours. Our goal serum levels were a trough < or =2 microg/ml and a peak between 6 and 12 microg/ml. We collected and analyzed trough and peak levels from all infants receiving this dosing regimen in the first week of life for at least 72 hours between 3/1/99 and 12/31/00. RESULTS: In total, 214 babies met our inclusion criteria, 75 of whom were <35 weeks gestation. 100% of babies of all gestational ages had a nontoxic trough level. For infants <35 weeks gestation, 79% had a therapeutic peak level, with a mean value of 6.8 microg/ml. For infants of at least 35 weeks gestation, 93% had a therapeutic peak level, with a mean value of 8.4 microg/ml. 92% of nontherapeutic peaks were too low. CONCLUSION: This study of once-daily gentamicin represents the largest sample size of pre-term infants published to date. The proposed regimen is simple and yields a high proportion of desirable levels. We recommend it for use in preterm and term newborns.     

Ethanol levels in honeybee hemolymph resulting from alcohol ingestion.

Our previous work on a social insect model of ethanol-induced behavior focused on behavioral studies of honeybees (Apis mellifera L.). We now investigate the dependence of honeybee blood ethanol concentration on both the amount of ethanol consumed and time elapsed since ingestion. Blood ethanol level was determined using gas chromatograph using hemolymph taken from harnessed bees. Significantly increased levels of ethanol in honeybee hemolymph were detected within 15 min of feeding bees alcohol. Within 30 min, ethanol concentration increased 2.7 times. The concentration of ethanol ingested also had a significant effect on blood ethanol level. However, postfeeding times greater than 30 min did not significantly increase ethanol concentration in bee hemolymph. This study integrates with our behavioral data on the effect of ethanol on honeybees. Our laboratory and field experiments show a correlation between the time frame for behavioral changes and significant increases of blood ethanol levels shown in this study.     

Heart rate and blood pressure variability as markers of sensory blockade with labour epidural analgesia

PURPOSE: To evaluate the correlation between the progression of somatosensory blockade and changes in autonomic outflow following the onset of labour epidural analgesia. METHODS: Twelve labouring parturients consented to participate in the study. Baseline electrocardiogram, blood pressure (BP) and respiratory rate were recorded for ten minutes. The epidural consisted of 0.125% bupivacaine with 50 microg of fentanyl (total volume 20 mL). Measurements were repeated for ten minutes after initiation of the block. The level of sensory block was measured bilaterally with loss of sensation to ice at two-minute intervals. Wavelet transform was used to obtain heart rate (HR) and BP variability every two minutes following the loading dose of epidural medication. High frequency power of HR variability was used to assess changes in parasympathetic activity. The total power of BP variability was used to assess changes in sympathetic activity. A nonparametric repeated measures ANOVA was used for the variability data, and a Spearman rank correlation test was used to evaluate the relationship between the sensory block and HR and BP variability. RESULTS: The sensory block progressed to T9 at ten minutes post-epidural and was the mirror image of the decrease in total power of BP variability. High frequency power of HR variability increased to a plateau at six minutes post-epidural. A significant correlation was found between the increase in sensory block and the observed decrease in BP variability (r = -1.000, P = 0.0028). CONCLUSION: In this study of labouring parturients, BP variability correlated with the progression of both sympathetic and somatosensory block following epidural anesthesia, while HR variability was shown to be a surrogate marker of increased parasympathetic activity.     

Predicting the severity of fetal anemia using time-domain measurement of volume flow in the fetal aorta.

OBJECTIVES: To assess the value of fetal aortic time-domain measurement of volume flow (using color velocity imaging quantification (CVI-Q)) in predicting the severity of fetal anemia. METHODS: This was a prospective observational study, in which 24 pregnant women with suspected fetal anemia due to rising anti-red blood cell antibody titers underwent cordocentesis. The fetal aortic time-domain volume flow was measured before fetal blood sampling for fetal hemoglobin investigation. We examined the correlation between increased fetal aortic time-domain volume flow (>2 SD for gestational age) and fetal anemia (hemoglobin level <2 SD for gestational age). RESULTS: Seventeen fetuses had anemia, and seven had normal hemoglobin. There was a strong correlation between the increase in fetal aortic time-domain volume flow and the drop in hemoglobin value (r = 0.81; P < 0.01). The sensitivity of this technique to predict fetal anemia was 81.3% and the specificity was 71.4%. The mean increase over time in aortic CVI-Q in anemic fetuses was 323.2 mL/min (95% CI, 200.1 to 446.4) compared with 86.9 mL/min (95% CI, -17.7 to 191.5) in the non-anemic group (P = 0.004). CONCLUSION: Fetal aortic time-domain measurement of volume flow is significantly increased in cases of fetal anemia due to red-cell alloimmunization. These findings can be used to improve the sensitivity, specificity and positive predictive value of the non-invasive techniques used to predict fetal anemia, and may help in the selection of pregnancies that require cordocentesis and transfusion.     

Questionnaire analysis of the swallowing‐related outcomes following total laryngectomy

Objective: To determine the effects of a total laryngectomy on the swallow and subsequent quality of life in head and neck cancer patients. Design: Cross‐sectional single centre cohort study. Setting: Head and Neck Oncology Unit, Tertiary Referral Unit. Patients: Sixty‐two patients who underwent total laryngectomy at our centre participated in the study. Methods: Subjects were stratified by age, sex, tumour stage, other procedures such as myotomy and nerve re‐implantation. Pharyngectomy, glossectomy, flap reconstruction, neck dissection and previous radio‐ and chemotherapy were also assessed to see if they affected swallow and subsequent quality of life. Main outcome was measured using the MD Anderson Dysphagia Inventory questionnaire. Results: Responses were received from 46 males and 16 females (response rate of 80.5%) with a mean age of 64.7 years (SD 9.4). Median follow‐up in patients was 90 months (range 1–276). The mean MD Anderson Dysphagia Inventory total score in our series of patients was 77.7 (SD 16.6). MD Anderson Dysphagia Inventory global score was 79.4 (SD 22.6), Emotional score was 77.7 (SD 17.8), Functional score 81.3 (SD 15.9) and Physical score was 74.1(SD 18). Statistically significant differences were seen between the emotional scores of glossectomised and non‐glossectomised patients (Mann Whitney, P = 0.04). No significant correlation was seen between the subscale scores and the remaining treatment variables such as age, gender, site, tumour stage, myotomy, nerve implantation, radiotherapy, reconstruction and major complications. Conclusion: This questionnaire study is the largest of its type to assess the swallow of patients who have undergone laryngectomy at a single centre. The overall result confirmed that most patients had a subjectively good swallow. Only glossectomy and the method of PE segment closure were shown to significantly affect swallowing outcomes following surgery. We recommend further work especially prospective studies pre and post surgery using this or similarly validated instruments to fully assess swallow in the laryngectomy population.     

Anterior decompression and stabilization of the spine as a treatment for vertebral collapse and spinal cord compression from metastatic malignancy

During a ten-year period, 77 patients with spinal instability caused by metastatic pathologic fractures of one or more vertebrae were treated with anterior decompression and stabilization by replacement of the affected vertebral bodies with methylmethacrylate, polymerizing in situ, augmented by Knodt distraction rods positioned anteriorly. No postoperative external support was required, and the fixation achieved by this method was not affected adversely by subsequent irradiation at a mean of 4020 rads. Sixty-two patients had major neurologic impairments preoperatively and required spinal cord and/or nerve root decompression anteriorly prior to fixation. Of these, 26 had complete neurologic recovery postoperatively, 16 others improved significantly, 20 remained unchanged, and one patient deteriorated neurologically. Five patients suffered failures of fixation, although two were successfully restabilized after a second operation. The remaining 72 patients enjoyed good or excellent resolution of spine pain postoperatively, and, in patients surviving their underlying malignancies, stability did not deteriorate during the follow-up period ranging from 42 to 146 months. Six patients developed spinal instability from tumor lysis at a different level between five and 95 months postoperatively. All were treated with successful decompression and stabilization. There was one wound infection among the 83 anterior stabilization procedures. However, three of the six patients requiring secondary posterior stabilization suffered wound dehiscences, and three of these became infected.     

Torsional properties of the Canal Master instrument.

The torsional properties of a new type of endodontic hand instrument, the Canal Master, were compared with conventional machined K-type endodontic files. Sizes 20 through 50 were tested in clockwise (CW) and counterclockwise (CCW) directions. Canal Master instruments exhibited significantly less torque at yield and at failure in both the CW and CCW directions. Rotation at failure was significantly greater for the Canal Master instruments in both CW and CCW directions. There was no significant difference in either torque or the amount of rotation for the Canal Master instruments when comparing CW versus CCW rotation. There was no clinically visible evidence of deformation of the Canal Master instruments prior to torsional failure.     

Outcome analysis in 654 surgically treated lumbar disc herniations.

This article reports the outcomes of 654 consecutive patients treated during a 4.5-year period. Patients had a microdiscectomy, a laminectomy plus microdiscectomy, or a decompressive laminectomy with a microdiscectomy. The causes of ruptured discs were lifting (31.4%), falls (10.2%), and sports (10.0%). Almost all patients had complained of leg pain (99%), and 79% had radicular pain in a dermatomal distribution. Thirty-three percent of the patients had been involved in industrial accidents, and 6% had legal claims pending during the surgical period. Almost 11% of the patients had complications, and there was one death caused by abdominal arterial bleeding. Patients were also rated according to the Prolo Functional-Economic Outcome Rating Scale to improve the ability to compare series in the future. Almost 80% of the patients had good outcomes as defined by scores on this scale of 8 (16.2%), 9 (33.2%), and 10 (26.9%). Several conclusions can be drawn from the results of this series: 1) most patients had good outcomes; 2) patients with nonindustrial injuries had better outcomes than did patients with industrial injuries; 3) professionals with legal concerns and laborers with industrial insurance had good outcomes; and 4) the Functional-Economic Outcome Rating Scale appears to be a useful tool for comparing different procedures more objectively and for comparing the outcomes across series.