Bupivacaine concentrations in lumbar cerebrospinal fluid in patients with failed spinal anaesthesia.

BACKGROUND: Spinal anaesthesia (SA) has high success rates. However, inadequate block after SA has been reported even in the absence of technical problems. Various mechanisms for failed SA (FSA) have been proposed, but reports of cerebrospinal fluid (CSF) concentrations of local anaesthetics (LA) after FSA are scarce. We report lumbar CSF concentrations of bupivacaine in 20 patients in whom adequate block after subarachnoid injection failed to develop. METHODS: All patients with inadequate block after subarachnoid injection of plain bupivacaine 0.5% and in whom a second subarachnoid injection of LA was to be performed as a rescue technique were eligible for entry into this study. A CSF sample was withdrawn immediately before injection of the second dose of LA. Patients in whom failure was obviously due to technical problems or inadequate dosage were excluded. Bupivacaine concentrations were assessed with high-performance liquid chromatography. RESULTS: During the study period of 15 months, 2600 spinal anaesthetics were performed. The failure rate was 2.7% (71 patients). In 20 patients (0.77%), CSF concentrations of bupivacaine were determined, which ranged from 3.36 to 1020 microg ml(-1). CONCLUSIONS: Inadequate CSF concentration of LA is a common reason for FSA. However, in 12 of our 20 patients, concentrations were above 73 microg ml(-1), a concentration that should lead to an adequate block. In these patients, maldistribution of bupivacaine could be responsible for FSA. In view of the absence of sufficient block, despite adequate lumbar CSF concentrations of bupivacaine, concerns about neurotoxicity with repeat injections may be warranted.

Bupivacaine concentrations in the lumbar cerebrospinal fluid of patients during spinal anaesthesia.

BACKGROUND: Data on bupivacaine concentrations in the cerebral spinal fluid (CSF) during spinal anaesthesia are scarce. The purpose of this study was to determine the concentration of bupivacaine in the lumbar CSF of patients with an adequate level of spinal anaesthesia after injection of plain bupivacaine 0.5%. METHODS: Sixty patients with an adequate level of spinal block after standardized administration of plain bupivacaine 20 mg in men and of 17.5 mg in women were studied. To measure the CSF bupivacaine concentration, we performed a second lumbar spinal puncture and obtained a CSF sample at a randomized time point 5-45 min after the bupivacaine injection. In addition, we calculated the half-life of bupivacaine in the CSF and tested the hypothesis that the level of spinal block is related to the lumbar CSF bupivacaine concentration. RESULTS: Men and women had CSF bupivacaine concentrations ranging from 95.4 to 773.0 microg ml(-1) (median 242.4 microg ml(-1)) and from 25.9 to 781.0 microg ml(-1) (median 187.6 microg ml(-1)), respectively. The large variability of bupivacaine concentrations obtained at similar times after subarachnoid administration made calculation of a meaningful half-life of bupivacaine in CSF impossible. There was no association between CSF bupivacaine concentration and spinal block level, and CSF bupivacaine concentrations for the same spinal block level differed between patients by six-fold. CONCLUSIONS: There is a large variability of CSF bupivacaine concentrations in patients with an adequate level of spinal anaesthesia.

[Laryngopharyngeal morbidity following general anaesthesia. Anaesthesiological and laryngological aspects]. / Pharyngolaryngeale Beschwerden nach Allgemeinanästhesien. Anästhesiologische und laryngologische Aspekte.

Laryngeal and pharyngeal complaints are among the subjective problems most frequently reported by patients after general anaesthesia involving endotracheal intubation, others being pain, nausea and vomiting. Hoarseness, sore throat, and vocal cord injuries restrict patients' social lives, and in some cases also their working lives. The most frequent types of laryngeal injury are swollen mucosa and haematoma of the vocal cords. Vocal cord paralysis occurs much less frequently. Knowledge of the pathophysiological aspects and other relevant factors associated with laryngopharyngeal morbidity are essential cornerstones of quality assurance in perioperative respiratory tract management. In this review specific sections are devoted to the implications of anaesthesia involving endotracheal intubation and laryngeal masks for laryngopharyngeal morbidity, and also particular aspects of thyroid gland surgery, cardiothoracic and bariatric surgery and obstetric and paediatric anaesthesia, and medicolegal aspects.

[Spinal anaesthesia in day-case surgery. Optimisation of procedures]. / Spinalanästhesie in der Tageschirurgie. Optimierung der Abläufe.

BACKGROUND: Since prilocaine is being increasingly used for day case surgery as a short acting local anaesthetic for spinal anaesthesia and because of its low risk for transient neurological symptoms, we compared it to bupivacaine. PATIENTS AND METHODS: Patients (n=88) who were scheduled for lower limb surgery with spinal anaesthesia randomly received 15 mg hyperbaric bupivacaine 0.5% or 60 mg hyperbaric prilocaine 2% (administered in a sitting position). Onset time, intensity, duration of the sensomotoric block, vital parameters and time of spontaneous miction were recorded and patients were questioned on satisfaction with the anaesthesia procedure and the occurrence of adverse side-effects after 24 h. RESULTS: Bupivacaine caused a significantly higher sensory block than prilocaine (T6 vs. T8). Both groups were similar in reaching an analgesic level of at least T12, block intensity and onset times. Median analgesic levels at T12 were maintained for 60 min with prilocaine versus 120 min with bupivacaine, regression of the motor block was 135 min versus 210 min, sensory block S1 was 240 min versus 360 min, and time for spontaneous miction was 306 min versus 405 min, respectively (differences for all comparisons were statistically significant). CONCLUSION: Under the present study conditions, hyperbaric prilocaine 2% was superior to hyperbaric bupivacaine 0.5% due to a shorter effect profile but otherwise equivalent quality of block. However, puncture in a sitting position and positioning with elevated torso for restriction of the cranial expansion of block spread might cause an enhanced sacral block with delayed recovery of bladder function.

The advanced health and disaster aid network: a light-weight wireless medical system for triage.

Advances in semiconductor technology have resulted in the creation of miniature medical embedded systems that can wirelessly monitor the vital signs of patients. These lightweight medical systems can aid providers in large disasters who become overwhelmed with the large number of patients, limited resources, and insufficient information. In a mass casualty incident, small embedded medical systems facilitate patient care, resource allocation, and real-time communication in the advanced health and disaster aid network (AID-N). We present the design of electronic triage tags on lightweight, embedded systems with limited memory and computational power. These electronic triage tags use noninvasive, biomedical sensors (pulse oximeter, electrocardiogram, and blood pressure cuff) to continuously monitor the vital signs of a patient and deliver pertinent information to first responders. This electronic triage system facilitates the seamless collection and dissemination of data from the incident site to key members of the distributed emergency response community. The real-time collection of data through a mesh network in a mass casualty drill was shown to approximately triple the number of times patients that were triaged compared with the traditional paper triage system.

Parity and blood pressure among four race-stress groups of females in Detroit.

Blood pressures (BPs) of 755 Detroit, Michigan, area females have been analyzed in relation to parity, race and residential stress. Mean BP values have been adjusted by standard methods of covariance analysis for differing effects of age and body size among various groups being compared. Adjusted systolic and diastolic BPs are found to be significantly different for black and white females. A residential stress effect is also seen for systolic BP among white females. However, none of the regression relationships between BP and parity is found to be significant in the race-stress groups included in the study. Thus, neither the consideration of race and stress nor adjustments for age and body size appear to add new information to the complex subject of BP as it relates to childbearing.