Craig D. McClain

Muscular dystrophy, anesthesia and the safety of inhalational agents revisited; again.

From the first successful public demonstration of ether by Drs Morton and Crawford, to more modern insoluble agents such as desflurane and sevoflurane, inhalational agents have been the medications upon whose shoulders the field of general anesthesia has progressed. Although the routine use of total intravenous anesthesia (TIVA), has become more commonplace with the advent of easily titratable agents such as propofol and remifentanil, volatile agents remain a fixture of modern anesthesia practice. The evolution of inhaled agents has continued from the 19th century to the present. Advances in surgical technique and patient safety forced the older, flammable agents to give way to modern halogenated compounds. Millions of anesthetics have been safely administered using any one of the various inhaled anesthetics. Despite great progress with inhaled agent pharmacology, there have been a number of disappointments as well. Halothane hepatitis and malignant hyperthermia were discovered to be rare but potentially lethal realities as the popularity of volatile anesthetics increased. A growing understanding of the limitations and unique risks of volatile agents became necessary. It soon became clear that the use of these agents led our specialty to be the not-so-proud owners of disease processes and syndromes that were nearly the sole purvey of the anesthesiologist. Hindsight is 20–20, and now it appears we have been reluctant to recognize, and give due attention, to yet another problem with volatile anesthetics. In 1987, Rubiano et al. (1) reported a case of a child with previously undiagnosed Duchenne’s muscular dystrophy (DMD) who underwent an uneventful adenoidectomy under deep halothane anesthesia without muscle relaxant. The child experienced rhabdomyolysis in the recovery room. He did not suffer a cardiac arrest (1). In 1990, Chalkiadis and Branc (2) reported the unexpected cardiac arrest of a young child with DMD in the recovery room after an uneventful isoflurane anesthetic. The child developed severe rhabdomyolysis, hyperkalemia, and suffered a cardiac arrest, despite the avoidance of succinylcholine. All this occurred after arrival in the recovery room with the child reportedly stable, awake, oriented, and conversant. A similar event, without cardiac arrest, was reported in 1999 by Obata et al. (3) The child in this case was known to have DMD. He received an uneventful sevoflurane anesthetic without the use of muscle relaxant. Once again, the event occurred in the recovery room. The child developed heel cord pain and was later noted to have extensive rhabdomyolysis. In 2005, Nathan et al. (4) described a similar event in a child with previously undiagnosed DMD. The anesthetic involved the use of both sevoflurane and isoflurane, but not succinylcholine. Yet again, during recovery from anesthesia, the patient suffered a cardiac arrest secondary to rhabdomyolysis. He had been extubated, awake, and oriented just prior to the arrest. Now in this issue of Pediatric Anesthesia, there is another report of a child who suffered a cardiac arrest secondary to rhabdomyolysis with subsequent hyperkalemia (5). Once again, after an uneventful intraoperative course, the arrest occurred in the recovery room in a child with previously undiagnosed DMD. As before, the child was awake, oriented, and talking prior to the arrest. What are we to make of these similarities? Correspondence to: Dr Terry Yemen, Department of Anesthesiology, Health and Sciences Center, University of Virginia, Charlottesville, VA, USA (email: tay9h@virginia.edu). Pediatric Anesthesia 2006 16: 105–108 doi:10.1111/j.1460-9592.2005.01801.x

Pial synangiosis in patients with moyamoya syndrome and sickle cell anemia: perioperative management and surgical outcome

OBJECT Many children with sickle cell anemia (SCA) also have clinical and radiographic findings of an arteriopathy suggestive of moyamoya syndrome. These patients may continue to experience strokes despite optimal medical management. The authors wished to define features of moyamoya syndrome associated with SCA and determine the results of surgical revascularization in these patients at early and late follow-up. METHODS The authors reviewed the clinical and radiographic records of all patients with moyamoya syndrome and SCA who underwent cerebral revascularization surgery using a standardized surgical procedure-pial synangiosis-from 1985 to 2008. RESULTS Twelve patients had SCA and moyamoya syndrome. Six patients were female and 6 were male. The average patient age at surgery was 11.3 years (range 3-22 years). All patients presented with ischemic symptoms, 11 (92%) with previous transient ischemic attacks, and 10 (83%) with completed strokes. Eleven patients (92%) had radiographic evidence of previous stroke at presentation. None presented with hemorrhage. Surgical treatment included pial synangiosis in all patients. Complications included 1 perioperative stroke, 1 wound infection, and 1 perioperative pneumonia. The average length of hospital stay was 5.7 days (including a 24-hour preoperative admission for hydration) and average blood loss was 92.5 ml/hemisphere (in a total of 19 hemispheres). Clinical and radiographic follow-up with an average of 49 months (range 9-144 months) demonstrated no worsening in neurological status in any patient. No clinical or radiographic evidence of new infarcts was observed in any patient at late follow-up, despite disease progression in 13 (68%) of 19 hemispheres. CONCLUSIONS The clinical and radiographic features of moyamoya syndrome associated with SCA appear comparable to primary moyamoya disease. Successful treatment of these patients requires multidisciplinary care involving hematologists, anesthesiologists, and neurosurgeons. Operative treatment of moyamoya syndrome using pial synangiosis appears to be safe and confers long-lasting protection against further stroke in this population, and provides an alternative for failure of optimal medical therapy in patients. This study underscores the potential merit of screening patients with SCA for moyamoya syndrome.

Long-Term Reduction in the Cost of Nutritional Intervention Achieved by a Nutrition Support Service

Background: Short-term effectiveness of Nutrition Support Services (NSS) has been previously evaluated. However, long-term clinical and economic impact is unknown. This study tests the hypothesis that the NSS improves patient care while reducing costs and that the service should be maintained on a long-term basis. Methods: Prospective monitoring of the effectiveness of nutrition support was done during the whole length of the study. Parameters studied included: (1) use of the appropriate route of nutritional delivery; (2) physician compliance with the recommendations given by the NSS; (3) Monitoring of total parenteral nutrition (TPN) waste; and (4) evaluation of costs. Results: A dramatic change in the route of delivery of nutrients occurred when NSS was instituted. This coincided with increased physician awareness that an enteral route for nutrient delivery could be safely obtained in most patients thus avoiding an indiscriminate use of TPN. The initial trend in reduction of TPN observed in the first year (46% reduction in TPN in one year, p < .001) of the institution of the NSS has continued through the years (78.6% reduction in the use of TPN by 1999, p < .001). The use of enteral nutrition (EN) increased proportionately. A reduction in TPN waste from 493 bags in 1991 to 34 bags in 1999 was also observed. Compliance with recommendations forwarded by the NSS is now above 90% compared with 50% in 1991. TPN cost in 1991 was

Total phenytoin concentrations do not accurately predict free phenytoin concentrations in critically ill children

513,246.00, which was reduced to

Global Surgery 2030: a roadmap for high income country actors

195,176.00 by 1999. We believe that significant savings in the cost of nutrition support have occurred as a result of the implementation of a NSS. Conclusions: Long-term maintenance of an NSS is warranted. The NSS provides constant surveillance and interventions regarding the appropriate nutrition support route, the adequacy of its use, and continuously minimizes waste.

Brain Injury and Nutrition

Objective: To determine the relationship between estimated free, measured free, and measured total phenytoin levels in critically ill pediatric patients, assess the utility of the Sheiner-Tozer equation in predicting free phenytoin levels, and identify comedications that may influence phenytoin binding or confound attempts to maintain therapeutic concentrations. Design: Retrospective chart review. Setting: Twenty-four-bed medical-surgical pediatric intensive care unit. Patients: Sixty critically ill pediatric patients receiving phenytoin for treatment of seizures in a large multidisciplinary intensive care unit. Interventions and Main Results: The linear correlation between free and total phenytoin concentrations was moderate (r = .795), but the mean difference between actual free concentrations and those estimated from total concentrations using the Sheiner-Tozer equation was −0.31 ± 0.5 &mgr;g/mL (95% confidence interval, −1.3 to 0.7). This difference was of concern, as 10% of patients had toxic free levels (>2 &mgr;g/mL) when simultaneously measured total levels were therapeutic (<20 &mgr;g/mL). The mean free/total phenytoin ratio was 0.13 ± 0.07 (range, 0.06–0.42) and varied considerably among patients. Free fractions were particularly elevated in children whose serum albumin concentrations were <2.5 g/dL (0.22, p < .001). However, the relationship between free phenytoin and serum albumin concentration appeared to be nonlinear. Coadministration of valproic acid and cefazolin also increased free fraction (p < .001). Conclusions: Measured total phenytoin concentrations are unreliable for directing therapy in critically ill children. In part, this is because phenytoin binding shows greater variability in this population than has been reported in adults. This phenomenon is exacerbated by coadministration of other highly protein-bound drugs. Instead, free phenytoin concentrations should be routinely measured in critically ill children to prevent possible intoxications and ensure therapeutic dosing. Corrections using the Sheiner-Tozer equation were unreliable.

Electroencephalogram monitoring during intracranial surgery for moyamoya disease.

The Millennium Development Goals have ended and the Sustainable Development Goals have begun, marking a shift in the global health landscape. The frame of reference has changed from a focus on 8 development priorities to an expansive set of 17 interrelated goals intended to improve the well-being of all people. In this time of change, several groups, including the Lancet Commission on Global Surgery, have brought a critical problem to the fore: 5 billion people lack access to safe, affordable surgical and anaesthesia care when needed. The magnitude of this problem and the worlds new focus on strengthening health systems mandate reimagined roles for and renewed commitments from high income country actors in global surgery. To discuss the way forward, on 6 May 2015, the Commission held its North American launch event in Boston, Massachusetts. Panels of experts outlined the current state of knowledge and agreed on the roles of surgical colleges and academic medical centres; trainees and training programmes; academia; global health funders; the biomedical devices industry, and news media and advocacy organisations in building sustainable, resilient surgical systems. This paper summarises these discussions and serves as a consensus statement providing practical advice to these groups. It traces a common policy agenda between major actors and provides a roadmap for maximising benefit to surgical patients worldwide. To close the access gap by 2030, individuals and organisations must work collectively, interprofessionally and globally. High income country actors must abandon colonial narratives and work alongside low and middle income country partners to build the surgical systems of the future.

Nutritional and metabolic variables correlate with amino acid forearm flux in patients with severe head injury.

This review has discussed the current status of metabolic alterations and demands, nutrient administration, and nutritional assessment of the head-injured patient. More work is necessary in all areas to further describe and ascertain the nutritional requirements of these patients. Future research in this area should involve specific nutrient requirement, modification of the acute-phase response, and possibly administration of growth factors.

The Impact of Natural Disaster on Pediatric Surgical Delivery: A Review of Haiti Six Months Before and After the 2010 Earthquake

We describe our experience with intraoperative electroencephalography in moyamoya surgery, a method to monitor for ischemic changes during the procedure and to minimize the risk of intraoperative and perioperative stroke. Case records and intraoperative electroencephalography recordings of all patients (n=220) treated with surgical revascularization for moyamoya (pial synangiosis) performed for 14 years (1994-2008) were reviewed. Electroencephalographic slowing occurred in 100 cases (45.5%), and was persistent in nine cases (9%). Slowing coincided with specific operative manipulations, most commonly while suturing the donor vessel to the pia, and during closure of the craniotomy. Slowing generally occurred bilaterally, independently of the side of intervention. The presence, length, and severity of slowing were not predictive of perioperative ischemic events. We present additional data on intraoperative electroencephalography with a modified montage to accommodate the craniotomy. Although not predictive of perioperative ischemic events in this series, electroencephalographic changes were correlated with specific operative interventions, and revealed global responses to unilateral manipulation. These findings suggest that prospective analyses of this technique may elucidate additional methods of predicting (and possibly preventing) perioperative ischemic events.

Anesthetic concerns for pediatric patients in an intraoperative MRI suite.

ObjectiveTo measure the arterial-venous amino acid flux across the forearm muscle in patients with severe head injury. DesignProspective, interventional study. SettingLevel I trauma hospital in the neuro-surgery intensive care unit (ICU) at a university medical center. PatientsEight nonsteroid-treated patients with severe head injury. InterventionsPatients were prospectively randomized to receive either standard or supplemental intravenous zinc therapy. Measurements and Main ResultsNet forearm alanine, glutamine, tyrosine, phenylalanine, and branch-chain amino acid forearm flux were measured and compared with metabolic markers of energy expenditure and nitrogen excretion.There was a significant inverse relationship between the measured energy expenditure/predicted energy expenditure ratio and glutamine flux (r2 = .62; p < .05). The patients with the highest measured energy expenditure/predicted energy expenditure ratio had the greatest release of glutamine from forearm muscle. Nitrogen balance was significantly correlated with leucine flux (r2 = .53; p < .05) and with isoleucine flux (r2 = .67;p < .05). The patients with the most positive nitrogen balance had the least release of branch-chain amino acids from skeletal muscle. Tyrosine flux was highly correlated with net amino acid flux (r2 = .76; p < .01). Tyrosine flux was therefore indicative of overall muscle catabolism. Four patients had an overall negative flux of amino acids from skeletal muscle. Three patients had an overall negative flux of branch-chain amino acids. ConclusionsThis preliminary descriptive report suggests that increased skeletal muscle efflux of amino acids correlates significantly with metabolic variables of hypermetabolism and hypercatabolism in nonsteroid-treated, headinjured patients. (Crit Care Med 1994; 22:393–398)