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Biomedical subjects

G J McCarthy

Publications and source records attributed to G J McCarthy.

At least 19 recordsLinked to original sources
PubMed2002

Eradication of endotracheal tube biofilm by nebulised gentamicin.

OBJECTIVE: To compare the efficacy of gentamicin, nebulised via the endotracheal tube (ET), with that of parenteral cefotaxime or parenteral cefuroxime in preventing the formation of ET biofilm. SETTING: General intensive care units in two university teaching hospitals. DESIGN: The microbiology of ET biofilm from 36 ICU patients eligible to receive antibiotic prophylaxis was examined. Peak and trough tracheal concentrations of gentamicin, cefotaxime or cefuroxime were measured in each patient group, on the 2nd day of intubation. PATIENTS: Twelve patients received gentamicin (80 mg) nebulised in 4 ml normal saline every 8 h, 12 cefotaxime (1 g, 12 hourly) and 12 cefuroxime (750 mg, 8 hourly). Prophylaxis was continued for the duration of intubation. MEASUREMENTS AND RESULTS: Samples of tracheal secretions were taken on the 2nd day of ventilation for determination of antibiotic concentrations. Following extubation, ETs were examined for the presence of biofilm. Pathogens considered to be common aetiological agents for VAP included Staphylococcus aureus, enterococci, Enterobacteriaceae and pseudomonads. While microbial biofilm was found on all ETs from the cephalosporin group, microbial biofilm of these micro-organisms was found on 7 of the 12 ET tubes from patients receiving cefotaxime [ S. aureus (4), pseudomonads (1), Enterobacteriaceae (1), enterococcus (1)] and 8 of the 12 ET tubes from patients receiving cefuroxime [Enterobacteriaceae (6), P. aeruginosa (1) and enterococcus (1)]. While microbial biofilm was observed on five ETs from patients receiving nebulised gentamicin, none of these were from pathogens for ventilator-associated pneumonia (VAP). Tracheal concentrations of both cephalosporins were lower than those needed to inhibit the growth of pathogens recovered from ET tube biofilm. The median (and range) concentrations for cefotaxime were 0.90 (<0.23-1.31) mg/l and 0.28 (<0.23-0.58) mg/l for 2 h post-dose and trough samples, respectively. Two hours post-dose concentrations of cefuroxime (median and range) were 0.40 (0.34-0.83) mg/l, with trough concentrations of 0.35 (<0.22-0.47) mg/l. Tracheal concentrations (median and range) of gentamicin measured 1 h post-nebulisation were 790 (352-->1250) mg/l and then, before the next dose, were 436 (250-1000) mg/l. CONCLUSION: Nebulised gentamicin attained high concentrations in the ET lumen and was more effective in preventing the formation of biofilm than either parenterally administered cephalosporin and therefore may be effective in preventing this complication of mechanical ventilation.

Administration, Inhalation↗
PubMed1999

Potency and time course of mivacurium block during sevoflurane, isoflurane and intravenous anesthesia.

PURPOSE: To determine the potency and time course of action of mivacurium neuromuscular block under routine clinical conditions during sevoflurane, isoflurane and intravenous anesthesia. METHOD: Patients were anesthetized with nitrous oxide 66% in oxygen and 1.5 MAC sevoflurane or isoflurane or a propofol infusion, neuromuscular block being monitored using mechanomyography. Potency was determined using administration of single doses of mivacurium of 40-100 micrograms.kg-1 and construction of dose-response curves (n = 72). The onset and duration of action were determined following a bolus dose of 0.2 mg.kg-1 of mivacurium (n = 30). RESULTS: The ED50 and ED95 (with 95% confidence limits) were estimated to be 42 (35-51) and 86 (74-98) micrograms.kg-1, 52 (45-60) and 89 (72-110) micrograms.kg-1, and 53 (45-62) and 95 (81-112) micrograms.kg-1 during sevoflurane, isoflurane and propofol anesthesia respectively (P < 0.05 between sevoflurane and propofol). Following administration of the 0.2 mg.kg-1 dose, neither the times (mean +/- SD) to maximum block (1.6 +/- 0.31, 1.7 +/- 0.21 and 1.6 +/- 0.45 min, respectively) nor the times to 25 and 90% recovery of T1 (20 +/- 4.5 and 33 +/- 8.8 min, 21 +/- 3.8 and 33 +/- 6.5 min, and 18 +/- 4.1 and 28 +/- 5.8 min respectively) were different among groups. The times to recovery of TOF ratio to 0.8 were 40 +/- 10.0, 36 +/- 8.5 and 29 +/- 5.5 min in the sevoflurane, isoflurane and propofol groups respectively (P = 0.017 between the sevoflurane and propofol groups). CONCLUSIONS: Under usual conditions of clinical anesthesia the potency of mivacurium was slightly enhanced during sevoflurane compared with intravenous anesthesia but the duration of action was only minimally prolonged during sevoflurane and isoflurane anesthesia.

Adolescent↗
PubMed1999

Implications of endotracheal tube biofilm for ventilator-associated pneumonia.

OBJECTIVE: To determine the relationship between, and antibiotic resistance of, endotracheal tube (ET) biofilm and pulmonary pathogens in ventilator-associated pneumonia (VAP). SETTING: General intensive care units in two university teaching hospitals. DESIGN: The microbiology of ET biofilm and tracheal samples from patients with and without VAP were compared. For individual patients, matching pairs of pathogens were confirmed as identical and characterised for antibiotic susceptibility. PATIENTS: 40 intensive care unit patients - 20 with VAP, 20 without VAP as control. The duration of intubation (median and range) was 6.5 days (3-17) and 5 days (2-10), respectively. MEASUREMENTS AND RESULTS: Samples of tracheal secretions were taken during ventilation for bacteriological culture. Following extubation, ETs were examined for the presence of biofilm. Isolates of high pathogenic potential included Staphylococcus aureus, enterococci, Enterobacteriaceae, pseudomonads and Candida spp. Where the same microorganism was found on tracheal and ET samples by phenotyping, these were confirmed as identical by genotyping and characterised for antibiotic susceptibility in both the free floating and biofilm forms. Seventy per cent of patients with VAP had identical pathogens isolated from both ET biofilm and tracheal secretions. No pairing of pathogens was observed in control patients (p < 0.005). Susceptibility data for these pairs show that the ET acts as a reservoir for infecting microorganisms which exhibit significantly greater antibiotic resistance than their tracheal counterparts. CONCLUSION: This investigation provides further evidence for the role of ET biofilm in VAP. The difficulty in eradicating an established microbial biofilm using antibiotics implies that increased attention must be directed towards modification of the ET to prevent or substantially reduce biofilm formation.

Adolescent↗
PubMed1998

Neuromuscular effects of rocuronium during sevoflurane, isoflurane, and intravenous anesthesia.

UNLABELLED: The potency and time course of action of rocuronium were studied in patients anesthetized with 66% nitrous oxide in oxygen and 1.5 minimum alveolar anesthetic concentration of sevoflurane or isoflurane, or a propofol infusion. Potency was estimated by using the single-bolus technique. Neuromuscular block was measured by stimulation of the ulnar nerve and by recording the force of contraction of the adductor pollicis muscle. The mean (95% confidence limits) of the 50% and 95% effective doses were estimated tobe 142 (129-157) and 265 (233-301) microg/ kg, 165 (146-187) and 324 (265-396) microg/kg, and 183 (163-207) and 398 (316-502) microg/kg during sevoflurane, isoflurane, and propofol anesthesia, respectively (P < 0.05 for sevoflurane versus propofol). The mean +/- SD times to onset of maximal block after rocuronium 0.6 mg/kg were 0.96 +/- 0.16, 0.90 +/- 0.16, and 1.02 +/- 0.15 min during sevoflurane, isoflurane, and propofol anesthesia, respectively. The respective times to recovery of the first response in the train-of-four (TOF) stimulation (T1) to 25% and 90% were 45 +/- 13.1 and 83 +/- 29.3 min, 35 +/- 6.1 and 56 +/- 15.9 min, and 35 +/- 9.2 and 55 +/- 19.4 min. The times to recovery of the TOF ratio to 0.8 were 103 +/- 30.7, 69 +/- 20.4, and 62 +/- 21.1 min, and the 25%-75% recovery indices were 26 +/- 11.7, 12 +/- 5.0, and 14 +/- 6.9 min, respectively. There were no differences among groups in the times for onset of action or to recovery of T1 to 25%. However, the times for recovery of T1 to 90%, TOF ratio to 0.8, and recovery index in the sevoflurane group were all significantly longer compared with the other two groups (P < 0.05, < 0.01, and < 0.01, respectively). We conclude that the effects of rocuronium, especially duration of action, are significantly enhanced during sevoflurane compared with isoflurane and propofol anesthesia. IMPLICATIONS: In routine clinical use, the effects of rocuronium are enhanced by sevoflurane, in comparison with isoflurane and propofol anesthesia, and the recovery is slower. Particular attention should be paid to monitoring of neuromuscular block during sevoflurane anesthesia.

Adult↗
PubMed1996

Potency and time course of action of rocuronium during desflurane and isoflurane anaesthesia.

We have studied the potency and onset and duration of action of rocuronium in patients anaesthetized with 1 MAC of desflurane or isoflurane (in 66% nitrous oxide). Potency was estimated using the single bolus dose technique. Neuromuscular block was measured by stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. The ED50 and ED95 of rocuronium were estimated as 138 (95% confidence limits 117-162) micrograms kg-1 and 281 (241-328) micrograms kg-1, and 126 (105-151) micrograms kg-1 and 283 (236-339) micrograms kg-1 during desflurane and isoflurane anaesthesia, respectively. The mean times to onset of maximum block after rocuronium 0.6 mg kg-1 were 1.0 (SD 0.10) min and 1.1 (0.15) min, respectively, during anaesthesia with desflurane and isoflurane. The respective times to recovery of T1 (the first response in the train-of-four (TOF) stimulation) to 25% and 90% were 36 (8.3) min and 54 (15.4) min during desflurane anaesthesia and 31 (8.2) min and 45 (12.7) min during isoflurane anaesthesia. The times to recovery of the TOF ratio to 0.7 were 66 (13.4) min and 52 (16.3) min and the 25-75% recovery indices 14 (5.3) min and 10 (3.2) min, respectively, in the desflurane and isoflurane groups. There were no differences in the estimated potency or onset of action of rocuronium during desflurane and isoflurane anaesthesia. However, duration of action tended to be longer curing desflurane anaesthesia although only the differences in times to TOF ratio of 0.7 and the recovery indices were close to being significantly different (P = 0.0503 and 0.0560).

Adolescent↗
PubMed1995

The effect of plasma cholinesterase activity on mivacurium infusion rates.

Although mivacurium is eliminated by plasma cholinesterase, previous investigations have revealed either no relationship or limited correlation between mivacurium infusion rates (IRs) and plasma cholinesterase activity. Assuming that such a relationship should exist, we used a novel approach to better demonstrate the relationship in humans. Fourteen isoflurane-anesthetized adults underwent standard neuromuscular monitoring. Mivacurium was then infused at 1.0 micrograms.kg-1.min-1 until twitch tension stabilized. The IR was then adjusted, using the Hill equation, to produce approximately steady state 50% (n = 14) or 90% (n = 13) twitch depression. Using these values for IR and steady-state twitch depression, the IRs expected to produce 50% and 90% twitch depression (IR50 and IR90, respectively) were estimated by on nonlinear regression. Both IR50 (r2 = 0.51, P < 0.005) and IR90 (r2 = 0.48, P < 0.01) were related to plasma cholinesterase activity; the coefficient of the Hill equation did not vary with plasma cholinesterase activity. We conclude that mivacurium IRs are, as expected, influenced by the activity of the enzyme responsible for its elimination.

Adolescent↗
PubMed1995

Dose-responses for edrophonium during antagonism of vecuronium block in young and older adult patients.

The dose-response relationship for edrophonium during antagonism of vecuronium-induced neuromuscular blockade was studied in two groups of adult patients of mean (SD) age 35 (10.0) years (n = 42) and 77 (5.4) years (n = 42) respectively. Neuromuscular block was monitored by recording the force of contraction of the adductor pollicis muscle following train-of-four stimulation. Six patients in each age group received 0.1, 0.3, 0.5, 0.7, 1.0, or 1.5 mg.kg-1 of edrophonium, or normal saline at 10% recovery of T1 (first response in the train-of-four) after a single dose of vecuronium 0.08 mg.kg-1. The train-of-four ratios were recorded continuously over the next 10 min and the values at 1 min intervals from 5 min onwards were used to construct the dose-response curves. The dose-response curves showed no significant difference between the two age groups except at 10 min. The estimated dose of edrophonium required for attaining a train-of-four ratio of 0.7 at 10 min was 0.9 and 1.3 mg.kg-1 in the younger and older groups, respectively (p < 0.05).

Adolescent↗
PubMed1994

Comparative study of ankle support devices.

The purpose of this study was to compare the ability of four commonly used ankle support devices (Active Ankle, Aircast Sport Stirrup, DonJoy Ankle Ligament Protector and Malleoloc) to restrict active inversion range of motion before and after exercise. The subjects also compared the devices on subjective characteristics, including stability, comfort, and ease of application and removal. Eighteen subjects had both ankles tested for maximum inversion on a specially designed measuring apparatus during three sessions: 1) before application, 2) before exercise with the support device, and 3) after exercise with the support device.

Adult↗
PubMed1993

Involving physicians in TQM. To gain physician support for quality management, hospital administrators must treat physicians as customers.

The process of integrating physicians into a hospital's total quality management (TQM) program is not simple. Physicians will not view TQM as an acceptable strategy in the absence of a positive working relationship with hospital managers. Physicians must see hospital managers as colleagues who can help improve their medical practices both in efficiency and patient care. The first step in involving physicians in TQM is creating an environment that enhances physician relationships. The CEO should be actively involved with the medical staff, and senior hospital managers should work at cultivating physician relationships. Physician needs and the centrality of the physician-management relationship should enter into every management discussion. Also, managers must solicit physician feedback regularly. Managers can introduce physicians to TQM by accompanying them to off-site TQM programs for a few days. Managers should also coordinate a continuing education program at the hospital, inviting a physician to address medical staff about TQM. Physicians are more likely to respond positively to one of their peers than they would to a consultant or business manager. Managers should then invite hospital-based physicians to participate on TQM interdisciplinary teams to resolve a problem chosen by the senior medical staff. The problem should be one that promises to be a quick fix, thereby ensuring demonstrable success of TQM and allaying any doubts. After an initial demonstration of TQM's success, the cycle is repeated. A year or two later, managers should invite off-site clinicians to join interdisciplinary teams on issues important to them.

Hospital Administration↗
PubMed1992

Estimation of the potency of ORG 9426 using two different modes of nerve stimulation.

The potency of ORG 9426, a new nondepolarising muscle relaxant, has been estimated using two different modes of nerve stimulation in patients anaesthetised with thiopentone, nitrous oxide-oxygen and intravenous fentanyl. The force of contraction of adductor pollicis was measured following a single twitch (ST) at 0.1 Hz or a train-of-four (TOF) mode of stimulation at 2 Hz every ten seconds. Dose-response curves were constructed using a single-dose method. The ED50, ED90 and ED95 were 147,272 and 305 micrograms.kg-1 respectively using the ST mode and 125,230 and 257 micrograms.kg-1 using the TOF mode of stimulation. The ED50S were not significantly different but the differences between ED90S and ED95S were significant (P less than 0.05) indicating greater sensitivity of the neuromuscular junction using TOF stimulation. The results of this study suggest that the information obtained by single-twitch stimulation is not the same as that obtained from the first response of the TOF stimulation, suggesting apparently increased sensitivity (and apparently greater potency) with the TOF mode of stimulation. Org 9426 appears to be a drug with relatively low potency.

Adolescent↗
PubMed1992

Dose-response relationships for neostigmine antagonism of vecuronium-induced neuromuscular block in adults and the elderly.

We have studied the dose-response relationship for neostigmine in 36 adult (ages 18-50 yr) and 36 elderly (ages > 70 yr) subjects during antagonism of neuromuscular block induced by vecuronium. All patients received vecuronium 0.08 mg kg-1 and neuromuscular block was monitored mechanomyo-graphically using the train-of-four (TOF) mode of stimulation. Six patients of each age group were allocated randomly to receive neostigmine 5, 15, 25, 35 or 45 micrograms kg-1 or saline at 10% recovery of T1 (first response in the TOF). TOF ratios were recorded continuously over the next 10 min and the values at 1-min intervals from 5 min onwards were used to construct the dose-response relationships. There was a significant difference (P < 0.05) in the time to spontaneous recovery of T1 to 10% between the adults (24 (SD 5.5) min) and the elderly (33 (7.8) min). Dose-response curves for neostigmine were parallel in the two age groups, but those for the elderly were significantly to the right of the curves for the adults. This suggests an apparently lesser relative potency of neostigmine, or the requirement of a larger dose, in the elderly for attaining antagonism of a moderately intense vecuronium block at the same time as in adults.

Adolescent↗
PubMed1992

Postoperative oxygenation in the elderly following general or local anaesthesia for ophthalmic surgery.

Peripheral oxygen saturation was recorded on the pre-operative night (between 2400 and 0600 h), the immediate postoperative period (first 60 min) and the first postoperative night (2400 to 0600 h) in 18 elderly patients aged 70 years or over presenting for elective ophthalmic surgery. Nine patients had surgery performed under general anaesthesia employing muscle relaxants and controlled ventilation and nine under local anaesthesia using a peribulbar block. The median (interquartile range) percentage of time during which the patients had an oxygen saturation of less than 90% was 0 (0-0.2) and 0.04 (0-0.4) on the pre-operative night, 0.7 (0-1.4) and 0.3 (0-1.2) in the immediate postoperative period, and 0.05 (0-0.16) and 0 (0-0.3) on the postoperative night in the general and local anaesthesia patients respectively. There were no significant differences between general and local anaesthesia in respect of these data and the overall incidence of significant desaturation was low. The present study could not demonstrate any adverse effect of general anaesthesia on oxygen saturation in patients undergoing minimally invasive surgery.

Aged↗
PubMed1992

Lack of interaction between propofol and vecuronium.

We estimated the potency of vecuronium and measured the onset and duration of its action during total intravenous anesthesia with propofol to examine the possibility of any interaction between these two drugs. Propofol infusion was administered according to a three-step dosage scheme, and neuromuscular block was monitored by measuring the force of contraction of the adductor pollicis muscle after single-twitch stimulation of the ulnar nerve at 0.1 Hz. A control group of patients were similarly studied during anesthesia with thiopental, nitrous oxide, oxygen, and fentanyl. The ED50 and ED95 (dose required to produce a 50% and 95% depression of twitch tension, respectively) of vecuronium in patients given total intravenous anesthesia (n = 24) were 24 (22-27, 95% confidence limits) and 41 (37-48, 95% confidence limits) micrograms/kg, respectively, and in the control group (n = 24), 20 (17-24) and 39 (34-37) micrograms/kg, respectively. The onset of action of an 80-micrograms/kg dose (2 x ED95) of vecuronium was 3.6 +/- 1.2 and 4.1 +/- 1.7 min (mean +/- SD), in the propofol (n = 10) and control (n = 10) groups, respectively. The respective times to recovery of the twitch height to 25% of control and the recovery indices (25%-75% recovery of twitch height) in the propofol versus control groups were 28.3 +/- 6.6 and 28.0 +/- 1.7 min and 13.3 +/- 6.8 and 15.4 +/- 11.9 min, respectively. There were no significant differences in any of the measured variables between the propofol and control groups, indicating the lack of any interaction between propofol and vecuronium.

Adult↗
PubMed1992

Hospital/physician relations. How to manage and improve ties with group practices.

As doctors increasingly choose to enter group practices, hospitals must find new ways to build and maintain good relationships with physician groups. Hospitals should go beyond standard communication and relationship-building techniques and surprise their group physicians with innovative services, such as direct-to-bed admissions for the doctors' patients, computer links with the hospital, or placing a medical records branch office at the group practice.

Group Practice↗
PubMed1991

Strength in numbers. Hospitals that encourage group practice development may have a strategic advantage in the 1990s.

Group practices have become increasingly popular among physicians in recent years. And as competition increases and operating margins become perilously thin, hospitals with significant group practice participation among medical staff appear to be in an enviable position. Before deciding to promote group practices, however, hospital managers should be become familiar with their advantages and disadvantages and determine whether a market exists for group practice development at their facility. The advantages for hospitals include more effective recruiting and a more stable patient base. Among the disadvantages are the fact that groups give physicians a stronger power base from which to request concessions from the hospital and that a preponderance of group-affiliated physicians on staff may discourage referrals from nongroup physicians. A number of considerations are involved in preparing for and coordinating group practice development. In the planning stages open communication with physicians is critical. Physician leaders and a cross section of active staff should participate. Planners should discourage formation of "groups without walls," in which hospitals manage group practices of physicians who remain at different sites. A hospital may, however, choose group-like arrangements (e.g., limited partnerships) without necessarily promoting group practice. Hospitals may also help a group purchase a facility of its own or even create the facility and allow the group to build equity in it.

Evaluation Studies as Topic↗
PubMed1991

TQM is key to improving services, but it's not for every hospital.

Total Quality Management (TQM) is a term that has been known to the manufacturing industry for years. Now the concept is finding its way into the vocabulary of the hospital industry as well. How can TQM positively affect systems in a health care institution? What can administrators expect from it? In the following article, the vice president of medical affairs at a Milwaukee hospital discusses the pros and cons of TQM.

Cost-Benefit Analysis↗
PubMed1990

Pressor responses to tracheal intubation after sublingual captopril. A pilot study.

The effect of sublingual captopril on the pressor response to intubation was studied in 40 patients. Captopril was used in one of two doses (12.5 mg and 25 mg) 25 minutes before tracheal intubation. Both doses were associated with a significant reduction in the pressor response to intubation (p less than 0.05) compared to placebo, but no significant difference existed between the two doses. Neither dose controlled changes in heart rate at intubation. Untoward hypotension occurred in the treatment groups. Caution is advised in the peri-operative use of angiotensin-converting enzyme inhibitors.

Administration, Sublingual↗