Lloyd A. Jacobs

Hepatic metabolic response to injury and sepsis

BACKGROUND Experimental reports have indicated that hepatic oxidative and synthetic metabolism may become depressed in sepsis. Because the mechanism of infection-related liver dysfunction has not been established, further study of these functional alterations could contribute to the therapeutic management of septic organ failure syndromes. However, recently controversy has arisen over the existence of these derangements that must be reconciled before further progress in this field can be made. METHODS Splanchnic balance studies for the measurement of glucose output and oxygen consumption were used to assess hepatic function in fasted normal volunteers (n = 18), injured patients (n = 10), and patients with sepsis (n = 18). The livers contribution to splanchnic metabolism was estimated from a comparison of splanchnic oxygen utilization in response to increases in the liver-specific process of glucogenesis. In addition, in vivo liver albumin production was determined by using the [14C] carbonate technique. RESULTS Glucose output after injury and sepsis was increased by 12.8% and 76.6%, respectively, compared with controls. On the basis of substrate balance studies, gluconeogenesis was estimated to account for 46%, 87%, and 93%, respectively, of splanchnic glucose output in each of the three groups. In patients with sepsis glucose output was also noted to be linearly related to regional oxygen consumption, indicating that these processes were coupled and increases in the respiratory activity of the splanchnic cellular mass could be accounted for by increases in new glucose output and gluconeogenic substrate clearance. The mean albumin synthetic rate increased during injury and sepsis by 22% and 29%, respectively, compared with normal volunteers. CONCLUSIONS These studies cast doubt on the commonly held notion that tissue respiratory dysfunction may occur during sepsis. On the contrary, hepatic function is accelerated during hyperdynamic sepsis, and evidence indicating oxidative or synthetic functional depression is lacking.

Neuropsychological performance one week after carotid endarterectomy reflects intra-operative ischemia.

Fourteen patients with severe bilateral carotid artery stenosis underwent carotid endarterec- tomy. Intra-operative ischemia was monitored by somatosensory evoked potentials (SSEP) bilaterally. Neuropsychological evaluations were completed within two days before operation and 4-9 days after operation. Complete loss of Nl-Pl or P1-N2 components of the SSEP (seen in 4 patients) was associated with a worsening of neuropsychological abilities (p < .01). Two of these patients subsequently had strokes (7 and 35 days after operation). No other patients in the series have had strokes. Patients whose Nl-Pl or P1-N2 amplitudes decreased by 50% or more performed worse after operation than patients with less severe reductions in these amplitudes (p < .02). Time since first ischemic symptoms, age, education, clamp time, pre-operative stroke, and interval from surgery to assessment were not statistically related to changes in neuropsychological abilities. Patients with ischemic events in the week prior to surgery tended to improve in neuropsychological abilities 4-9 days after operation (p < .05). Recentness of ischemic episode, however, was not related to intra-operative SSEP change. Results suggest the potential utility of intra-operative SSEP monitoring and early post-operative neuropsychological assessments both for clinical and research purposes. Stroke Vol 15, No 3, 1984

Neuropsychological impairment after carotid endarterectomy correlates with intraoperative ischemia

Detailed neuropsychological assessments were performed before and shortly after carotid endarterectomy in thirty-four patients. The degree of intraoperative ischemia was assessed by monitoring the somatosensory evoked cortical potential change upon carotid clamping. Changed neuropsychological performance was found to be related to intraoperative ischemia most clearly in patients with a history of previous stroke and in those with more severe vascular disease. In such patients greater SSEP change was correlated with greater neuropsychological change postoperatively.

Neuropsychological improvement following endarterectomy as a function of outcome measure and reconstructed vessel

30 patient receiving right or left carotid reconstruction and 15 medically matched controls were compared pre- and post-surgically on measures of motor speed, sustained vigilance, verbal memory and verbal and nonverbal intellectual function. The group receiving right sided vessel reconstruction demonstrated the largest post-operative improvement in intellectual function in any of the groups. The findings suggest that increased blood perfusion following right sided endarterectomy facilitates the right hemispheres exclusive control of bilateral attention/arousal responses. In addition, findings suggest that detection of post-endarterectomy improvement may be dependent on the specific task dimension sampled, e.g., speed vs. cognitive ability and verbal-graphic vs. nonverbal symbol manipulation.

Cardiac tamponade due to an iatrogenic pericardialdiaphragmatic hernia

Because of its ease, safety, and effectiveness, surgeons are increasingly using the subxiphoid approach to drain pericardial effusions and to insert epicardial pacemakers. Although we could find no previous reports of iatrogenic pericardial-diaphragmatic hernias in the literature, experience with a recent patient who developed this problem after a subxiphoid pericardial drainage suggests that it may become much more frequent. Physicians should strongly suspect this complication in patients with a triad of previous subxiphoid pericardial incision and signs of bowel obstruction and tamponade.

An assessment of the variability of early scalp-components of the somatosensory evoked response in uncomplicated, unshunted carotid endarterectomy.

Although many publications deal with the usefulness of the SER in CEAs, the criteria of calling a SER abnormal during a CEA are largely arbitrary. One way to define the limits of normalcy for SERs during the CEA will be to analyze the SER tracings obtained during unshunted and uncomplicated (intra- and postoperative) CEAs. In 23 such CEAs (10 right, 13 left; clamptime 10-23 mins.), data analysis at the ipsilateral parietal electrode, on stimulation of the contralateral median nerve (square pulse -5.1/sec, 10-30 V, 200 microseconds; bandpass-30-3000 Hz trials-500 stimuli), revealed that (1) latency fluctuations of the N20 (21.4 msec) were narrowest, being less than 1.5 msec different during and after clamping compared to the preclamp latency in all 23 CEAs, whereas those of P25 (27.4 msec) and N35 (38.5 msec) were greater than 2.0 msec different from the preclamp latency in 3 and 8 CEAs respectively, and (2) the amplitudes of N20, P25 and N35 measured from the preceding peak of opposite polarity, fell to less than 75% of the preclamp value on 3, 4 and 7 CEAs respectively. It is concluded that N20 was the most stable of the first three short-latency components in the SER and should perhaps be most relied upon to predict abnormality of the SER during CEAs.

Carotid Endarterectomy in a Patient With Ankylosing Spondylitis—A Case Report

Access to the cervical internal carotid artery may occasionally be limited by the mandible. Management of symptomatic carotid occlusive disease in a pa tient suffering from ankylosing spondylitis is described in which the carotid bifurcation is obscured by the vertical mandibular ramus. The application of technique usually reserved for high internal carotid artery lesions to this situa tion is discussed. In the case reported here, the preferred approach of mandibu lar subluxation allowed successful carotid endarterectomy.

Hemodynamic benefits of verapamil after aortic reconstruction

Because of the high incidence of coronary artery disease (CAD) in patients undergoing aortic surgery, and because myocardial oxygen consumption is proportional to blood pressure x heart rate (HR) (pressure-rate product), it is important to prevent increases in these parameters postoperatively. The effect of verapamil, a calcium channel antagonist, on these parameters was evaluated in 30 patients undergoing abdominal aortic reconstruction. Postoperatively HR increased 27% in 19 patients without CAD and 47% in 11 patients with CAD. Pressure-rate product (blood pressure x HR) increased 17% and 31% in these two groups, respectively. Verapamil was able to reduce postoperative HR by 3% in patients without CAD and by 13% in patients with CAD. Verapamil reduced pressure-rate product 8% and 18%, respectively, in the two groups. These reductions were statistically significant in patients with CAD and occurred without reductions in cardiac output or left ventricular ejection fraction. Thus the postoperative increases in myocardial oxygen demand appeared to be primarily related to increased HR after aortic surgery, and these were reduced by verapamil without impairing blood flow or cardiac function.