Umbilical cord blood pH and Apgar scores as an index of neonatal health

In an effort to determine the clinical usefulness of Apgar scoring and cord pH in neonatal management, specimens of umbilical cord blood were obtained after 257 of 329 consecutive deliveries at a community-based hospital. A notable number of babies who were born in a vigorous state were in fact acidotic (umbilical arterial pH greater than 1 SD below mean). Seventy-two percent of acidotic babies had an Apgar score greater than 7 at 1 minute, and 92% had an Apgar score greater than 7 at 5 minutes. Correlation coefficients of Apgar scores at 1 and 5 minutes and arterial pH with the health status of newborn infants were poor. A chi 2 analysis of arterial pH and Apgar scores at 1 and 5 minutes indicated that a larger number of sick babies had an Apgar score less than 7 and acidosis than expected by pure chance. However, the sensitivity values of the Apgar score at 1 minute (0.48) and 5 minutes (0.24) and the arterial pH (0.40) for predicting sick children limit the clinical usefulness of these tests. While technically feasible in a community hospital, routine cord pH measurements add little to neonatal evaluation and management.

EEG sleep in elderly depressed, demented, and healthy subjects

In a prospective study of EEG sleep patterns in 25 elderly depressives, 25 elderly demented patients, and 25 healthy, elderly control subjects, the sleep of depressives was characterized by reduced REM sleep latency, increased REM percent and first REM period density, and altered temporal distribution of REM sleep, as well as by diminished sleep maintenance (correlated significantly with Hamilton ratings of depression: multiple R = -0.42, p less than 0.05). In contrast, the sleep of demented patients showed reduced REM sleep percent, but normal REM temporal distribution, increased loss of spindles and K-complexes (the latter correlating significantly with severity of cognitive impairment as measured by the Folstein score: multiple R = -0.59, p less than 0.01), and less severe sleep maintenance difficulty than for depressives. An examination of REM latency demonstrated a skewed distribution in depression (i.e., 42% of nights with sleep-onset REM periods), but a normal distribution in the controls and demented subjects. A REM latency cut-off score of 30 min correctly classified 68% of all patients (kappa = 0.36; p less than 0.005), compared with 78% correctly identified in our retrospective study (Reynolds et al. 1983).

Increasing cardiac rate by measurement of right ventricular temperature

A pacemaker that increases pacing rate in response to exercise enables the pacemaker patient to improve his state of well-being. Possible sensors include atrial rate, Q-T interval, pH, venous oxygen saturation, respiratory rate, cardiac output, body motion, and blood temperature. To determine the efficacy of right ventricular blood temperature as an indicator of exercise, an experimental temperature-controlled pacemaker was developed and was evaluated in dogs. A resulting algorithm was implemented in a microcomputer-based VVI pacemaker which reliably detected exercise and rest from blood temperature when totally implanted. The pacemaker generated two pacing rates to provide increased cardiac output. Data is being obtained to establish feasibility in humans.

Cortical wave amplitude and eye movement direction are correlated in REM sleep but not in waking

Eye movement related potentials were recorded bilaterally from the lateral geniculate body and visual cortex in five cats during REM sleep and waking. During REM sleep polygraphic recordings showed that these potentials have significantly greater amplitudes (primary waves) in the visual cortex and lateral geniculate body ipsilateral to the direction of the corresponding rapid eye movements. This amplitude difference was seen as a mean increase of 38.2% over the contralateral side and was found in 94.0% of wave pairs. The correlation between horizontal eye movement direction and amplitude of the waves is specific to REM sleep as there were no measurable differences in the waking state. These results are discussed with respect to possible mechanisms and functions of this lateralized wave system and its state dependency.

Location and spike-train characteristics of cells in anterodorsal pons having selective decreases in firing rate during desynchronized sleep

Extracellular microelectrode recordings were made from single neurons in the pontomesencephalic brain stem of head-restrained but nonanesthetized cats whose behavioral state was continuously monitored polygraphically. A population of neurons was encountered with the unusual property of progressively decreasing discharge rate as the cats passed from waking (W) through synchronized sleep (S) to desynchronized sleep (D). In many cases there was a complete cessation of firing in desynchronized sleep, suggesting the designation D-off cell for this neuronal subtype. The D-off cell population was distributed in a bandlike zone across the brain stem at the pontomesencephalic junction with dense concentration of cells in aminergic nuclei: the serotonergic dorsal raphe and raphe linearis centralis and noradrenergic locus ceruleus and peribrachial regions. Aside from a sparse distribution in the central tegmental field, there were no D-off cells in pontine reticular nuclei where cells of the D-on type abound. The proportion of cells showing the D-off property and the magnitude of the state-related change were correlated across nuclear groups as follows: raphe and peribrachial (highest), locus ceruleus (intermediate), and reticular (lowest) for both values. The firing rates of D-off cells tended to be low in waking with very regular interspike intervals. This characteristic firing pattern and the anatomical distribution suggests that D-off cells may be tentatively identified as aminergic. The marked contrasts in aminergic neuronal activity between waking and desynchronized sleep are interpreted as possibly playing a role in state generation through progressive distribution of cholinergic neurons postsynaptic to the D-off cell population. Predictable results would not only be a change in the excitability of the postsynaptic population but also a change in response mode related to a shift in neurotransmitter throughout the brain.

REM sleep burst neurons, PGO waves, and eye movement information

Pontogeniculooccipital (PGO) waves appeared almost simultaneously in both lateral geniculate nuclei (LGB), but in each case on had a larger amplitude and preceded the other by a few milliseconds. The larger, earlier wave is called the primary wave. Primary waves were found to appear with equal frequency in each LGB. During rapid eye movement sleep (REM sleep), LGB primary waves were ipsilateral to the direction of rapid eye movements. During REM sleep a group of cat midbrain neurons, which we call PGO burst cells, fired in stereotyped bursts at fixed latencies before ipsilateral primary waves, but they almost never fired bursts when the primary waves were contralateral. PGO burst neuron discharge also correlated with the direction of rapid eye movements during REM sleep. In wakefulness, PGO burst cells fired single spikes, not bursts, which had some correlation with LGB waves when averaged by computer. The results suggest that PGO burst cells are output elements in the PGO wave-generation system ad that PGO waves convey eye movement information to the sensory visual system in REM sleep. They also may have a role in the production of saccade-related waves in the visual system during wakefulness.

Reduction of deep sepsis after total hip arthroplasty

The role of the operating room environment in the development of deep sepsis after total hip arthroplasty was studied at four centers. The incidence of deep sepsis after 5,865 total hip arthroplasties performed in the four centers varied from 0.5% to 2.3%. Procedures performed in a conventional operating room were associated with the highest incidence of deep sepsis (1.3%). The use of a vertical, unidrectional airflow system with a helmet aspirator suite was associated with the lowest incidence of deep sepsis (0.6%). Although patients with previous hip surgery had an increased incidence of deep sepsis regardless of the operating room environment, those procedures performed in a vertical, unidrectional facility had a lower incidence of deep sepsis. Newer techniques designed for the reduction of airborne contamination of the operative wound seem to reduce the incidence of deep-wound sepsis after total hip arthroplasty, especially in patients with previous hip surgery.

Ponto-geniculo-occipital (PGO) burst neurons: correlative evidence for neuronal generators of PGO waves

A newly discovered class of neurons, ponto-geniculo-occipital (PGO) burst neurons, has PGO wave relationships of phase-leading, stereotyped discharge bursts, and the highest reported discharge specificity and coherence; these neurons thus fulfill correlative criteria for output generator neurons for PGO waves. The PGO burst neurons are recorded in a discrete dorsal brainstem area in apposition to the brachium conjunctivum.

Deep infection following total hip arthroplasty

Deep sepsis is a serious postoperative complication of total hip arthroplasty, causing additional suffering, loss of function, need for additional treatment, and possibly early death. In a series of sixteen patients, the only effective treatment was complete extirpation of all implants combined with appropriate long-term administration of antibiotics. In fifteen patients the original operative objectives were not achieved.

Five years experience with operating room clean rooms and personnel-isolator systems

Two horizontal flow, laminar airflow type clean rooms have been used for almost all clean orthopedic surgery at St. Luke's Hospital in Denver since March 1971. This experience covers approximately 4000 cases, including 1100 total hip and total knee arthroplasties. Three different types of helmet aspirator systems have also been evaluated. Our conclusions from this experience are: (1) All types of orthopedic surgery may be easily and conveniently performed in the clean room and with scrubbed personnel wearing helmet aspirator systems; (2) mechanical upkeep of the clean room is minimal; (3) airborne bacteria counts have been reduced at least 80 percent compared to a regular operating room, and more than 90 percent when scrubbed personnel wear the helmet aspirator system; (4) sterile surface contamination, including the wound, has been reduced at least 80 percent; and (5) the deep infection rate for total hip replacements with at least a 2-year follow-up has been 7.6 percent (10/131) in a regular operating room and 1.6 percent (5/319) in the clean room. With the combined use of the clean room, helmet aspirator systems, and perioperative antibiotics, no infections have occurred in an additional 350 cases with a 1-year follow-up.

Solitary bone cyst with epiphyseal involvement: a case report

A large solitary bone cyst involving the epiphysis produced 5.0 cm shortening of the proximal humerus in a 15-year-old girl. Biopsy revealed the cyst was filled with thin yellow fluid under pressure and lined by a fibrous membrane. X-rays 9 months after biopsy demonstrated progressive cyst obliteration. A review of literature revealed no similar case. It is postulated that solitary cysts rarely may involve the physeal and epiphyseal structures and thereby retard longitudinal bone growth.