[The value of sonography in the intensive care unit for the diagnosis of diaphragmatic paralysis]. / Wertigkeit der Sonographie auf der Intensivstation zur Diagnostik von Zwerchfellparesen.

PURPOSE: To assess the value of bedside sonography in the detection of diaphragmatic paralysis in patients in the intensive care unit. METHODS: In this study, 100 patients who were admitted to the intensive care unit after thoracic operations were evaluated. Sonography of each hemidiaphragm was performed with coronal scans at the mid-axillary line on both sides with the patient supine. Absent and paradoxical diaphragmatic movement was considered to be indicative of diaphragmatic paralysis. All patients underwent additional fluoroscopy within 5 days. RESULTS: In 13 patients (13%) sonography revealed diaphragmatic paralysis. All these results were confirmed with fluoroscopy resulting in a sensitivity and specificity for sonography of 100%. CONCLUSION: Bedside sonography of the diaphragm at the intensive care unit is a reliable tool for diagnosing diaphragmatic paralysis.

The cerebral and cardiovascular effects of cisatracurium and atracurium in neurosurgical patients.

UNLABELLED: Drugs for neurosurgical patients should not increase intracranial pressure (ICP) or change cerebral perfusion pressure (CPP) and cerebral blood flow. This double-blind, cross-over study compares the effects of a single (3 x effective dose producing 95% twitch depression) intravenous bolus dose of cisatracurium 0.15 mg/kg with atracurium 0.75 mg/kg on mean red blood cell flow velocity in the middle cerebral artery (CBFV; transcranial Doppler), ICP (intraventricular or intraparenchymal monitor), mean arterial pressure (MAP), CPP (MAP-ICP), and heart rate (HR) every minute during a 15-min study period. Included in the study were 14 sedated and ventilated adult neurosurgical patients. After the cisatracurium bolus, ICP, CPP, CBFV, MAP, and HR did not change, and no histamine related events were observed. After the atracurium bolus, ICP, CPP, CBFV, and MAP decreased. The lowest values of ICP (-16% of baseline), CPP (-5%), CBFV (-8%), and MAP (-7%) were recorded 2-4 min after the atracurium bolus injection. After this transient decrease, MAP and CPP returned to baseline, whereas CBFV and ICP transiently exceeded baseline values. The highest values of CBFV (5%) and ICP (17%) were recorded 9-12 min after the atracurium bolus injection. Five patients showed a typical histamine response after atracurium, with a decrease in MAP and flushing. Excluding these five patients eliminated statistical significance in ICP, CPP, CBFV, and MAP differences. In conclusion, cisatracurium demonstrated fewer cerebral and cardiovascular hemodynamic side effects in sedated adult neurosurgical patients. IMPLICATIONS: This double-blind study in sedated and mechanically ventilated adult neurosurgical patients demonstrates that an intravenous bolus dose of the neuromuscular blocker cisatracurium results in less cerebral (intracranial pressure, cerebral perfusion pressure, middle cerebral artery blood flow velocity) and cardiovascular (blood pressure) hemodynamic side effects, compared with an equipotent dose of atracurium.

Lack of nonshivering thermogenesis in infants anesthetized with fentanyl and propofol.

BACKGROUND: Sweating, vasoconstriction, and shivering have been observed during general anesthesia. Among these, vasoconstriction is especially important because-once triggered-it minimizes further hypothermia. Surprisingly, the core-temperature plateau associated with vasoconstriction appears to preserve core temperature better in infants and children than adults. This observation suggests that vasoconstriction in anesthetized infants may be accompanied by hypermetabolism. Consistent with this theory, unanesthetized infants rely on nonshivering thermogenesis to double heat production when vasoconstriction alone is insufficient. Accordingly, the authors tested the hypothesis that intraoperative core hypothermia triggers nonshivering thermogenesis in infants. METHODS: With Ethics Committee approval and written parental consent, the authors studied six infants undergoing abdominal surgery. All were aged 1 day to 9 months and weighed 2.4-9 kg. Anesthesia was maintained with propofol and fentanyl. The infants were mechanically ventilated and allowed to cool passively until core (distal esophageal) temperatures reached 34-34.5 degrees C. Oxygen consumption-the authors' index of metabolic rate-was recorded throughout cooling. Because nonshivering thermogenesis triples circulating norepinephrine concentrations, arterial blood was analyzed for plasma catecholamines at approximately 0.5 degree C intervals. Thermoregulatory vasoconstriction was evaluated using forearm-fingertip, skin-surface gradients, with gradients exceeding 4 degrees C, indicating intense vasoconstriction. The patients were subsequently rapidly rewarmed to 37 degrees C. Regression analysis was used to correlate changes in oxygen consumption and plasma catecholamine concentrations with core temperature. RESULTS: All patients were vasoconstricted by the time core temperature reached 36 degrees C. Further reduction in core temperature to 34-34.5 degrees C did not increase oxygen consumption. Instead, oxygen consumption decreased linearly. Hypothermia also failed to increase plasma catecholamine concentrations. CONCLUSIONS: Even at core temperatures approximately 2 degrees C below the vasoconstriction threshold, there was no evidence of nonshivering thermogenesis. This finding is surprising because all other major thermoregulatory responses have been detected during anesthesia. Infants and children thus appear similar to adults in being unable to increase metabolic rate in response to mild intraoperative hypothermia.