Steven C. Walker

Tracheal intubation using alfentanil and no muscle relaxant: is the choice of hypnotic important?

Administration of alfentanil followed by propofol intravenously (IV) without neuromuscular blockade for induction of anesthesia provides adequate conditions for tracheal intubation.Other hypnotic drugs have not been thoroughly investigated in this regard. Accordingly, 140 ASA physical status I and II premedicated outpatients were randomly assigned to one of seven groups (n = 20/group). Patients in Groups I-VI received alfentanil 40 micro g/kg followed by etomidate 0.3 mg/kg, propofol 2 mg/kg, or thiopental 4 mg/kg. One half of these patients (Groups II, IV, VI) also received lidocaine 1 mg/kg IV prior to the administration of the above drugs. Patients in group VII received d-tubocurarine 3 mg followed by thiopental 4 mg/kg and succinylcholine 1 mg/kg. Ninety seconds after induction, laryngoscopy and endotracheal intubation were attempted and graded. Patients in Group V (alfentanil/thiopental) were significantly (P < 0.05) more likely to have a clinically unacceptable response to intubation (55%) (e.g., vigorous coughing, purposeful movement, or requirement for succinylcholine to complete intubation) compared with patients who received propofol (35%) or etomidate (20%). Alfentanil/etomidate yielded intubation conditions comparable to those achieved with alfentanil/propofol and d-tubocurarine/thiopental/succinylcholine. Lidocaine appeared to improve intubating conditions, although this improvement did not reach statistical significance. The results suggest that healthy, premedicated patients with favorable airway anatomy who have received alfentanil 40 micro g/kg can be reliably tracheally intubated 90 s after administration of propofol 2 mg/kg or etomidate 0.3 mg/kg. (Anesth Analg 1997;84:1222-6)

Surgical morbidity and the risk of amputation due to infected puncture wounds in diabetic versus nondiabetic adults

We reviewed the hospital course of 77 diabetic and 69 nondiabetic subjects who had incision, drainage, and exploration of infected puncture wounds of the foot. Diabetics were 5 times more likely to have multiple operations and 46 times more likely to have a lower extremity amputation than nondiabetics. The interval from injury to surgery was significantly longer in diabetics than nondiabetics. Total lymphocyte count and hemoglobin, hematocrit, and albumin values were significantly lower in diabetics than in nondiabetics. Diabetic amputees had higher prevalences of nonpalpable pulses, nephropathy, neuropathy, and osteomyelitis as compared with diabetic nonamputees. The neuropathic diabetic foot is not protected by pain. When combined with other comorbid factors, this may increase morbidity associated with puncture wounds of the foot.

Healing rates of diabetic foot ulcers associated with Midfoot fracture due to Charcot's arthropathy

The aim of this study is to compare the effectiveness of total contact casts based on wound location in groups of patients with diabetes mellitus with neuropathic ulcerations under the forefoot and patients with midfoot ulcerations associated with acute Charcot’s arthropathy. Twenty‐five consecutive diabetic patients with Meggitt‐Wagner grade I neuropathic foot ulceration (NU) and 22 consecutive diabetic patients with neuropathic ulceration and acute Charcot’s arthropathy (CU) were selected for study. Larger wounds took longer to heal in both the CU (p < 0.0001) and NU groups (p < 0.0001). Duration of ulcer prior to treatment also was significantly associated with increased healing time in both groups (p = 0.008 NU, p = 0.03 CU). The CU group had larger wounds (10.3 ± 4.6 vs 7.7 ± 4.0 cm2, p = 0.04) but took significantly less time to heal (28.4 ± 13.0 vs 38.8 ± 21.3 days, p = 0.04) than did subjects with neuropathic ulcerations only. The NU group had their ulcers present for a significantly longer period of time prior to contact casting (88.5 ± 98.3 vs 17.7 ± 12.9 days, p = 0.001). In this study, subjects with ulcerations secondary to acute Charcot fractures healed more rapidly than in previous reports with healing times of forefoot neuropathic ulcers similar to previous studies. Every patient’s ulcer healed. There were no cast‐related ulcerations, infections, or hospitalizations. Concerns regarding the safety of total contact casts to treat well‐vascularized superficial forefoot and midfoot plantar wounds appear to be unfounded.

Mortality following lower extremity amputation in minorities with diabetes mellitus

The aim of this study was to identify the age adjusted and level specific mortality rate in African-Americans, Hispanics and non-Hispanic whites (NHW) during the perioperative period following a lower extremity amputation. We identified amputation data obtained from the Office of Statewide Planning and Development in California for 1991 from ICD-9-CM codes 84.11-84.18 and diabetes mellitus from any 250 related code. Amputations were categorized as foot (84.11-84.12), leg (84.13-84.16) or thigh (84.17-84.18). Death was coded under discharge status. Age adjusted and level specific mortality rates per 1000 amputees were calculated for each race/ethnic group. The age adjusted mortality was highest for African-Americans (41.39) compared to Hispanics (19.69) and NHWs (34.98). Mortality was consistently more frequent for proximal amputations. We conclude that mortality rates for persons with diabetes hospitalized for an amputation varied by race, gender and level of amputation. Higher prevalence or severity of risk factors may explain the excess mortality observed in African-Americans.

Puncture wounds : Normal laboratory values in the face of severe infection in diabetics and non-diabetics

PURPOSE Using infected puncture wounds as a basis for comparison, we pose the question of whether white blood cell count (WBC) and erythrocyte sedimentation rate (ESR) is lower in diabetic patients with foot infections as compared with nondiabetic patients. PATIENTS AND METHODS This case control study consisted of two groups, both with infected puncture wounds of the foot, admitted to a 700-bed urban university teaching hospital between 1985 and 1992. The experimental group contained 77 patients with diabetes mellitus. The control group consisted of 69 patients without diabetes. All subjects received emergent incision and drainage of the affected site. RESULTS Results revealed a normal WBC count in 57.6% of patients. The ESR was normal in 36.3% of admissions. More nondiabetic patients presented with normal ESR than diabetic patients (62.3% versus 13.7%, respectively; P < 0.0001). Diabetic patients had a significantly higher mean WBC count and ESR than did nondiabetic patients. Pain was the principal complaint more frequently in nondiabetic patients (92.9% NDM versus 70.1% DM, respectively; P < 0.005). Erythema (72.7% versus 51.4%; P = 0.008), and drainage (36.4% versus 7.1%; P < 0.001) were more common in diabetic patients. CONCLUSION We conclude that, while a glaringly elevated WBC count or ESR should alert the clinician to the possibility of infection, normal values should not be relied upon to rule out a serious event.

Return to work after burn injury

The research literature suggests but does not test the hypothesis that differential factors determine when a patient will return to work after serious burn injury. In this study, factors influencing time before return to work after serious burn injury were investigated prospectively as part of a large burn research project. Sixty-five patients with burns who had returned to work were followed. Several variables were examined, including percent total body surface area burned, total percent of partial-thickness burn, total percent of full-thickness burn, duration of treatment, payment source for treatment, sex, race, type of burn, and age. The most significant predictor of time before return to work was percent total body surface area burned, followed by percent body surface area with full-thickness burns, percent body surface area with partial-thickness burns, and number of weeks of treatment, respectively. Sufficient data were available to develop a regression equation to specifically predict time before return to work. The data presented here are useful in informing patients, families, employers, and health-funding agencies as to the probable delay before return to work that can be expected after serious burn injury. In particular, predictability refinements are possible with the regression equation developed in this study.

One Hundred Ninety-five Cases of High-voltage Electric Injury

High-voltage electric injury (HVEI) is associated with a high incidence of extremity compartment syndrome and of major amputation. The purpose of this study was to review our experience with HVEI and to attempt to develop predictors of the need for fasciotomy and amputation in patients with HVEI. The records of the 195 patients with HVEI who were admitted to a single burn center during a 19-year period were reviewed. Evidence for muscle necrosis, to include myoglobinuria and elevated creatine phosphokinase (CPK) levels, was noted. A total 187 patients (95.9%) survived to hospital discharge. A total of 56 underwent fasciotomy within 24 h of injury; 80 patients underwent an amputation during the hospitalization. Fasciotomy was predicted by presence of myoglobinuria with an overall accuracy of 72.8%. Amputation was predicted by a logistic model incorporating myoglobinuria, undergoing a previous fasciotomy, and age, with an overall accuracy of 73.3%. HVEI was associated with high amputation risk and a low rate of mortality in patients admitted to our burn center. Patients with gross myoglobinuria are at higher risk of requiring fasciotomy and/or amputation.

The clinical neuromuscular pharmacology of cisatracurium versus vecuronium during outpatient anesthesia.

Neither comparisons of the clinical neuromuscular effects of cisatracurium and vecuronium nor comparative studies of their antagonism by neostigmine have been reported.In addition, the efficacy of administering cisatracurium in divided doses has not been investigated. Accordingly, we applied supramaximal electrical stimuli to the ulnar nerve of 165 ASA physical status I and II patients receiving nitrous oxide/alfentanil/propofol anesthesia. Forty-five patients received cisatracurium 5, 10, or 15 micro g/kg, and the evoked response at the adductor pollicis was recorded for 15 min. One hundred-twenty patients received cisatracurium 5, 10, or 15 micro g/kg or normal saline placebo followed 5 min later by either cisatracurium 100 micro g/kg or vecuronium 100 micro g/kg (always after placebo). Time to clinical onset (maximal ablation of single twitch response) was measured. When the evoked response spontaneously recovered to 10% of control height, neostigmine 5, 10, 30, or 50 micro g/kg or placebo was administered, and recovery of neuromuscular function was recorded for the next 15 min. The clinical onset of vecuronium without priming (2.8 +/- 0.8 min) (mean +/- SD) was significantly (P < 0.05) faster than the onset of cisatracurium without priming (4.6 +/- 1.4 min). Cisatracurium 5, 10, or 15 micro g/kg administered before cisatracurium 100 micro g/kg significantly (P < 0.05) accelerated the time to complete ablation of the evoked response (3.9 +/- 0.9, 2.9 +/- 0.8, or 3.0 +/- 0.9 min, respectively) compared with cisatracurium 100 micro g/kg without priming. The dose of neostigmine required to achieve 50% assisted recovery of the train-of-four ratio at 5 min was significantly (P < 0.05) smaller in patients who received vecuronium (29.1 [17.9-55.3] micro g/kg) (mean [95% confidence interval]) compared with those who received cisatracurium (53.7 [31.6-131.5] micro g/kg). Given its faster clinical onset and greater sensitivity to antagonism by neostigmine, we conclude that vecuronium may be more suitable than cisatracurium for use in outpatient anesthesia. Implications: We investigated the onset of muscle relaxation using intravenous vecuronium and cisatracurium and assessed the ability of neostigmine to antagonize (reverse) this effect. Our results suggest that vecuronium works faster than cisatracurium and is more sensitive to neostigmine. Vecuronium therefore may be more useful than cisatracurium in outpatient anesthesia. (Anesth Analg 1997;85:1278-83)

Infected Puncture Wounds in Diabetic and Nondiabetic Adults

OBJECTIVE To evaluate bone and soft tissue pathogens resulting from puncture wounds among diabetic and nondiabetic adults. RESEARCH DESIGN AND METHODS We used a case-control design to compare bacterial pathogens in diabetic and nondiabetic subjects with foot infections precipitated by puncture injuries. We used ICD-9-CM code E920.8 to identify 77 diabetic and 69 nondiabetic patients admitted to the hospital for infected puncture wounds. We identified surgical bone and soft tissue cultures and number and type of organisms per culture. RESULTS Nondiabetic subjects had significantly less osteomyelitis (13 vs. 35%, P < 0.01) than diabetic subjects and were infected by fewer organisms. Pseudomonas was the most common cause of osteomyelitis among nondiabetic subjects (P < 0.001). Staphylococcus aureus was more common in diabetic bone (P < 0.001) and soft tissue (P < 0.001) infections. Polymicrobial osteomyelitis was more common in diabetic subjects. There was a longer delay until diabetic subjects received medical treatment compared with nondiabetic subjects (8.7 vs. 5.3 days, P < 0.002). Diabetic subjects were more likely to have neuropathy (P < 0.001) and to have sustained their injuries while barefoot (P < 0.006). CONCLUSIONS Puncture wounds in diabetic subjects were commonly associated with polymicrobial infections. Pseudomonas was the most common cause of nondiabetic osteomyelitis. These results have implications for differential emergent and chronic treatment of puncture wounds in diabetic versus nondiabetic subjects.

Gait pattern alteration by functional sensory substitution in healthy subjects and in diabetic subjects with peripheral neuropathy.

OBJECTIVE To evaluate the ability of diabetic and nondiabetic individuals to learn to use a lower extremity sensory substitution device to cue gait pattern changes. DESIGN Case-control study. SETTING Gait laboratory. PARTICIPANTS Thirty diabetic persons and 20 age- and education-matched nondiabetic controls responded to advertisements for study participation. INTERVENTION Participants walked on a treadmill at three speeds (1, 2, and 2.5mph) with auditory sensory feedback to cue ground contact greater than 80% duration of baseline. MAIN OUTCOME MEASUREMENTS The variables measured included gait cycle (steps per minute) and number of times per minute that any step during a trial exceeded 80% duration of ground contacted compared with a measured baseline step length for each speed. RESULTS Persons in both groups were able to rapidly and significantly alter their gait patterns in response to signals from the sensory substitution device, by changing their gait cycles (nondiabetic group, F(17,124) = 5.27, p < .001; diabetic group, F(5,172) = 3.45, p < .001). Post hoc analyses showed early gait cycle modification and error reduction among both groups. The nondiabetic group learned to use the device significantly more quickly than the diabetic group during the slow (1mph, t = 3.57, p < .001) and average (2mph, t = 2.97, p < .05) trials. By the fast (2.5mph) ambulation trial, both groups were performing equally, suggesting a rapid rate of adjustment to the device. No technical failures from gait trainer malfunction occurred during the study. CONCLUSIONS Diabetic persons with neuropathy effectively used lower extremity sensory substitution, and the technology is now available to manufacture a durable, effective lower extremity sensory substitution system.