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Biomedical subjects

H P Simmen

Publications and source records attributed to H P Simmen.

At least 19 recordsLinked to original sources
PubMed1999

The real incidence of percutaneous injuries in the operating room--a prospective study.

Despite the frequent exposure of operating room personnel to blood and other body fluids and the obvious risk of occupational transmission of HIV infection, the real incidence of injuries after needle sticks or cuts in the operating room has not been well investigated. Every injury occurring in the operating room during one thousand consecutive elective and emergency procedures was studied and the risk for acquiring an HIV infection was calculated. There were 50 injuries during 761 elective procedures (6.6%) and 23 injuries during 239 emergency operations (9.6%). There was one single injury during 91 minimally invasive endoscopical procedures (1.1%). The surgeon was the person most frequently injured (3.5%). The injury rate of the scrub nurse varied between 1.4% and 2.8% according to the surgeon's experience. The operating room personnel is at risk for an occupational transmission of blood born pathogens. If the seroprevalence of HIV in surgical patients is estimated at 0.4% the calculated probability for a surgeon to acquire HIV infection over a 30-year career amounts to 0.3%.

Accidents, Occupational↗
PubMed1998

Bacterial concentrations in pus and infected peritoneal fluid--implications for bactericidal activity of antibiotics.

Little is known about how many bacteria are present at an infectious focus at the onset of antibiotic therapy. The number of cfu was determined in pus and infected peritoneal fluids obtained from 41 patients. Pathogens were detected in 71% of specimens. There were high concentrations of bacteria in culture-positive samples, in both soft-tissue and peritoneal infections, averaging 2 x 10(8) cfu/mL. These concentrations were much higher than the standard inoculum size used in in-vitro susceptibility tests, 5 x 10(5) cfu/mL. The impact of this discrepancy on antibacterial efficacy was studied with amikacin, ciprofloxacin, imipenem and piperacillin against Escherichia coli and Staphylococcus aureus. The inhibitory and bactericidal activities of amikacin and ciprofloxacin determined with high inocula were two to four times lower than with standard inocula, whereas the activity of piperacillin was diminished at least 128-fold. Similar activity was observed with these drugs in Mueller-Hinton broth and peritoneal fluid. The bactericidal activity of imipenem was reduced in peritoneal fluid. Thus, conditions prevailing at the infection site may compromise antibiotic activity determined in vitro.

Abdominal Abscess↗
PubMed1998

[Diagnosis and therapy of vascular injuries in posterior knee dislocation].

AIM: We demonstrate the management and treatment of dislocation of the knee associated with vascular injury. The goal of the treatment is to avoid complications due to ischemia. The injured vessel can be repaired either by direct suture or by interposition of a saphenous vein graft. Capsule and ligaments should be reconstructed secondarily. PATIENTS AND METHODS: The charts of ten patients treated in the Division of Traumatology of the University of Zurich between 1979 and 1996 have been retrospectively checked. RESULTS: In eight of ten patients the injured vessel has been reconstructed with a saphenous vein graft, in one patient the artery has been repaired by direct suture. In one patient a flap of the intima has been refixed by endarterectomy. In five patients the knee has been stabilised with a transfixation (external fixation). In two patients the ligaments and the capsule were reconstructed at the time of vascular repair, in seven patients the reconstruction has been performed secondary. CONCLUSIONS: In case of a dislocation of the knee the examination of the vessels is mandatory. In case of a critical perfusion the "on table"--angiography is the procedure of choice. As an alternative method duplex sonography has been established. The vascular reconstruction is performed by saphenous vein graft interposition. We recommend to reconstruct ligamentous and capsular structures secondary.

Adult↗
PubMed1997

Inflammatory response after abdominal trauma, infection, or intestinal obstruction measured by oxygen radical production in peritoneal fluid.

BACKGROUND: Reactive oxygen intermediates (ROI) have been implicated in many pathophysiological processes of inflammatory tissue damage and tissue repair. In the present study we compared the production of ROI in three different types of tissue damage in surgical patients. METHODS: Peritoneal fluid specimens were harvested during the initial operation and postoperatively from 25 surgical patients with abdominal trauma, intraabdominal infection, and intestinal obstruction. The optical density at 412 nm, representing the peroxidation of hemoglobin, was measured to assess intraperitoneal ROI production. Patients were categorized into 3 groups: (A) infected patients with good outcome, (B) patients after trauma or obstruction with good outcome, and (C) patients with poor outcome due to persistent or secondary infection and multiple organ failure. Analysis of variance (ANOVA) and paired t test were used for statistical analysis. RESULTS: Overall, the ROI production decreased significantly at days 2 and 3 compared with day 0 and 1 (P = 0.0013). No initial differences of intraoperative ROI concentrations were found among the three groups; however, patients with a poor outcome showed increased ROI values after 4 to 5 days (P = 0.038) when compared with the good outcome group. CONCLUSIONS: We have demonstrated that intraperitoneal ROI production (1) can be measured in patients with intraabdominal tissue damage, (2) is not different between patients with intraabdominal infections, abdominal trauma, or intestinal obstruction, and (3) correlates with the clinical picture and the presence of an inflammatory intraabdominal focus or tissue damage.

Abdominal Abscess↗
PubMed1996

[Immune response to a single dose of a novel kind of hepatitis A vaccine following splenectomy].

BASIC PROBLEM AND OBJECTIVE: The immune response to parenteral antigens is reduced in persons without spleen. The seroconversion rate was measured after application of a new type of vaccine against hepatitis A (immunopotentiating reconstituted influenza virus virosome [IRIV]) in patients who had undergone a splenectomy after trauma. PATIENTS AND METHODS: 26 patients (23 men and 3 women, mean age 34.9 +/- 9.7 [25-65] years) with anti-hepatitis A virus (HAV) antibody titres < 20 mIU/ml (maximally 17 mIU/ml) were given a single dose of 0.5 ml of the IRIV hepatitis A vaccine 1 to 14 (mean 9.4) years after splenectomy. Immediately after the immunisation and 14 and 28 days afterwards anti-HAV titres were determined. A titre rise to < 20 mIU/ml was counted as seroconversion. At the first and last titre measurement immunoglobulins, neopterin and beta-microglobulin levels were also measured as additional markers. RESULTS: The seroconversion rate was 69.2% (18/26) after 14 days (geometric titre mean: 39 mIU/ml) and rose to 88.5% (23/26) after 28 days (geometric titre mean 74 mIU/ml). Seroconversion occurred in the three nonresponders after a second dose of the vaccine. All measurements of the immunological markers were within normal limits. CONCLUSION: A single dose of a new type of vaccine against hepatitis A confers adequate protection even in those persons who had a splenectomy.

Adult↗
PubMed1996

[Subcapital humerus fracture with lesion of the axillary artery. 2 case reports and review of the literature].

Two cases of fractures of the humeral neck in association with an axillary artery injury are reported. Even now, there are still only 14 well-documented cases in the literature. Trauma, pattern of injuries and treatment are analyzed. The treatment is focused on preservation of hand function, which is more important than shoulder motion. Neurovascular damage causes an impairment of hand function. The priorities of treatment (reperfusion versus osteosynthesis) are dictated by the degree of ischemia. Long-term disability is determined by brachial plexus injury.

Aged↗
PubMed1995

Is laparoscopic appendectomy the new 'gold standard'?

OBJECTIVES: To determine the efficacy of laparoscopic appendectomy compared with open appendectomy in patients with acute appendicitis and to compare the morbidity between the two groups. DESIGN: Prospective sampling of 102 patients who underwent diagnostic laparoscopy and laparoscopic appendectomy for acute appendicitis and retrospective hospital chart review of 204 patients who underwent open appendectomy for acute appendicitis. RESULTS: The mean +/- SD duration of surgery was 83 +/- 29 minutes in the laparoscopic group and 64 +/- 30 minutes in the open appendectomy group (P < .001). Hospital stay was shorter in the laparoscopic group (P < .04). There was no difference in the complication rate between the patients who underwent laparoscopic appendectomy (13%) and the patients who underwent open appendectomy (11%). The occurrence of postoperative ileus was correlated with the duration of operation (P < .01) but not with laparoscopic appendectomy. CONCLUSIONS: The results confirm that laparoscopic appendectomy had a longer time of surgery, a shorter hospital stay, and no difference in complications. Further investigation will likely establish that laparoscopic appendectomy can be considered the "gold standard."

Acute Disease↗
PubMed1995

Soft tissue infections of the upper extremities with special consideration of abscesses in parenteral drug abusers. A prospective study.

Despite surgical advances and new antibiotics, upper extremity infections continue to present a serious problem. Soft tissue infections of the upper extremities were prospectively examined to elucidate incidence, cause, bacterial pathogens involved, and treatment. Special attention was paid to infections associated with parenteral drug abuse. During an 18-month period all patients over 16 years of age presenting for treatment of an established infection were included in the study. Conservative treatment consisted of immobilization and antibiotics. Radical débridement with removal of all necrotic tissue was the guideline for operative care. In addition, for both regimens a penicillinase-resistant antibiotic was administered. A total of 415 patients (271 men and 144 women; mean age 36.7 +/- 14.5 years) were enrolled into the study, 55 of whom were parenteral drug abusers; 45 of these were HIV-reactive. Infections of fingers (excluding paronychia), paronychia and abscesses at injection sites were the most common diagnoses. Operative and conservative treatment were performed in 285 and 130 patients respectively. Staphylococcus and streptococcus species were the predominant organisms recovered from 212 specimens of pus. Anaerobic bacteria and yeasts were of minor importance. Therefore, a penicillinase-resistant antibiotic is a good initial choice.

Abscess↗
PubMed1995

Nephrotoxicity, high frequency ototoxicity, efficacy and serum kinetics of once versus thrice daily dosing of netilmicin in patients with serious infections.

The effect of dosing regimen on nephrotoxicity, high frequency ototoxicity, efficacy and serum kinetics was studied in a prospective, randomised clinical study. Therapy was started with total daily doses of 6 mg/kg given once (od) or thrice (tid) daily to 56 and 57 patients, respectively. Subsequent doses were adjusted according to serum levels. No major differences in toxicity or efficacy were noticed between od and tid regimens: clinical failures occurred in two and two patients, four and five patients suffered from a decrease of > or = 20 dB at least unilaterally at one frequency between 8 and 18 kHz, six and seven patients had a > 25 mumol/L or > 25% increase in serum creatinine, respectively. Serum creatinine or creatinine clearance did not change significantly during either therapy. Major differences between the two study groups were limited to pharmacokinetic parameters. Od dosing resulted in higher peak (mean of 21.6 vs 7.2 mg/L) and lower trough levels (0.5 vs 1.4 mg/L). Half-lives of netilmicin determined between 1 and 8 h increased significantly during therapy with tid (from a mean of 2.75 to a mean of 3.33 h, P < 0.01) but not significantly with od (rise from 2.8 to 3.03 h). Much longer half-lives were determined between 8 and 24 h in the od group (mean of 5.7 h, P < 0.01). In conclusion, only minimal differences in toxicity and efficacy were observed. Their clinical relevance appears to be minimal.

Adolescent↗
PubMed1995

[Determination of serum lead levels following shotgun injury].

Lead concentration of pellets is over 95%. Four patients who had sustained shotgun injury with retained shotgun bullets in the body are described. In 3 of 4 patients the blood level of lead was increased, as well as the concentration of Delta-ALA in the urine. In all four patients symptoms due to lead intoxication were absent. Usually the surgical goal is limited to a proper debridement of large wounds in the soft tissue. Therefore it is mandatory to assess the lead level in the blood and the concentration of Delta-ALA in the urine. Thus asymptomatic lead intoxication can be recognized and treated.

Adult↗
PubMed1995

Review of typical ice hockey injuries. Survey of the North American NHL and Hockey Canada versus European leagues.

Ice hockey is considered to be one of the fastest and roughest of all sports. Prospective injury reports of the North American National Hockey League, the Canadian Amateur Hockey Association and of several European teams (UdSSR, CSSR, Sweden and Switzerland) are reviewed to evaluate the patterns, anatomic locations, circumstances and sequelae of ice hockey-related injuries. Although different injury reporting systems are used in North America and Europe, knee injuries (sprains of the collateral ligaments) accounted for the majority of games missed (40%), followed by injuries to the shoulder (dislocation, acromio-clavicular joint separation, rotator cuff strain and tears, 20%), the groin (15%), and the back (10%). Mandatory helmets and face masks reduced the number of facial and eye injuries to a quarter from 1972 to 1983. The frequency of only concussion but also cervical spine lesions is increasing. The prevention of head, face, eye and neck injuries should mainly be accomplished by enforcement of current rules (mandatory helmets with face masks) and institution of new rules. Improvement in protective equipment would also have the effect of decreasing the frequency of injuries. Ice hockey is the fastest team sport and involves both finesse and controlled aggression. It is also considered to be one of the roughest of all sports. In recent years, ice hockey has grown tremendously in popularity, not only in the United States and in Canada but also in many European countries [1]. The number of both professional and amateur hockey players has increased with the expanding interest in the sport around the world [1].(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Chylothorax after blunt thoracic trauma].

The diagnosis of chylothorax following blunt chest trauma is rare, only few cases have been reported. We describe three patients with chylothorax following blunt chest trauma. Conservative treatment consists of drainage, in severe cases mechanical ventilation with PEEP and total parenteral nutrition. In case of persisting and/or increasing chylus production, thoracotomy and ligation of the thoracic duct may be required. In all of our patients thoracostomy was the definite therapeutic modality, no thoracotomy was necessary.

Adult↗
PubMed1995

Biochemical analysis of peritoneal fluid in patients with and without bacterial infection.

OBJECTIVE: To find out if the concentrations of biochemical variables in peritoneal fluid differed in the presence or absence of infection. DESIGN: Prospective study. SETTING: University hospital, Switzerland. SUBJECTS: 80 patients undergoing abdominal operations, 23 of whom were operated on for an intra-abdominal infection. 57 Patients with no sign of infection served as controls. MAIN OUTCOME MEASURES: Concentrations of 24 biochemical variables measured in specimens of peritoneal fluid obtained during the operation. RESULTS: Major differences between specimens taken from infected and uninfected patients including: glucose 5.4 compared with 0.8 mmol/l, lactate 7.9 and 17.2 mmol/l, aspartate aminotransferase 83 and 520 U/l, phosphate 1.1 and 3.7 mmol/l, potassium 4.5 and 10.1 mmol/l, lactate dehydrogenase 2021 and 7998 U/l, and gamma-glutamyl transferase 57 and 169 U/l. CONCLUSION: Intra-abdominal infection significantly alters the composition of peritoneal fluid. The assessment of milieu factors at the site of infection may help in the design of more predictive in vitro tests to guide antimicrobial treatment of intra-abdominal infections. In addition, the knowledge of discriminatory variables in peritoneal fluid may be useful in the diagnosis of intra-abdominal infection.

Abdomen↗
PubMed1995

[An overview of snow-boarding injuries].

Snowboarding is increasing dramatically in popularity in Switzerland as well as other countries. Work aimed at improving the design of the boards and of the boots and bindings has also increased rapidly during recent years. Most injured snowboarders are fit young men and boys who describe themselves as beginners and have had a minimal amount of instruction at an officially approved training centre. Appropriate snowboard training has mostly been quite inadequate, and protective devices (e.g. waterproofed support gloves). The anatomical distribution and the types of injuries sustained in snowboarding differ from those in alpine skiing. The wrist (and forearm) and the ankle are the most frequent locations of injuries (23%) as against the knee and thumb in alpine skiing. Sprains and strains were the most frequent types of injuries (46%), followed by fractures (28%) and contusions (13.5%). The snowboard injury rate was higher than in alpine skiing (1.7-8/1000 snowboard days versus 2-4/1000 ski days). Falling forward on the slope was the major mechanism of injury (80%), and torsion the next most frequent (20%). Snowboarding injuries were sustained most often on ice and hardpacked snow, compared with soft powder snow for alpine skiing injuries. Appropriate preseason conditioning, snowboarding lessons from a certified instructor, appropriate selection of rigorously tested equipment and use of protective devices are the main steps that must be taken to prevent injuries.

Adolescent↗
PubMed1995

[Osteosynthesis of subcapital humerus fractures with unconventional use of implants].

The osteosynthesis of subcapital humerus fractures with the commonly used plates is often critical because of the little space subacromial, the irritation of the blood supply by the broad plates and the poor proximal anchorage without angle stability. The osteosynthesis with blade plates (children hip plate or blade plates for small adults) for isolated subcapital fractures or a blade plate like modified DC-plate for subcapital fractures with a shaft component or severe osteoporosis is thought to be a reliable alternative. We treated 34 patients aged between 18 and 85 years (mean 44 years) with blade plates. 33 patients had a good fracture healing and subjectively free shoulder motion after 3 months. One patient had distal implant loosening because of insufficient medial contact. The fracture healed after refixation.

Adolescent↗
PubMed1994

[Necrotizing soft-tissue infections of the extremities].

The term "Necrotizing soft tissue infections" describes a group of limb- and sometimes lifethreatening infections mostly of the limbs. The necrotizing soft tissue infections are classified, depending on the involved tissue level, microbiology and clinical course: 1. primarily located in the subcutaneous level and fascia: 1.1 hemolytic streptococcal gangrene, 1.2 necrotizing fasciitis, 1.3 gram-negative, synergistic, necrotizing cellulitis, 1.4 clostridial cellulitis, 1.5 anaerobic nonclostridial-cellulitis; 2. primary located in the muscle: 2.1 clostridial myonecrosis, 2.2 streptococcal myositis. Between 1989 and 1992 17 patients with necrotizing soft tissue infections were treated at the Department of Surgery, University Hospital of Zurich. Incipient necrotizing soft tissue infections are underestimated easily due to atypical or minor initial signs. The infections may be caused by a variety of bacteria, spread rapidly and can lead to a critical condition. The surgical treatment has to be aggressive with extensive debridement of the affected areas supported by intensive care. Delayed or even omitted surgical treatment, inappropriate therapeutic concepts and incomplete debridement with compromises may have fatal consequences. Repeated debridement as well as amputation of the affected limb is justified to guarantee the patient's survival.

Adult↗
PubMed1994

Monitoring serum concentrations for once-daily netilmicin dosing regimens.

A once-daily dosing regimen for aminoglycosides is less expensive, at least as effective and possibly less toxic than multiple-daily dosing regimens. Once-daily dosing might also allow the frequency of measuring the serum concentrations of these antibiotics to be reduced since two of the major objectives of monitoring, high peak and low trough concentrations, are more likely to be achieved with this regimen. A novel strategy for monitoring serum concentrations which relies on a single sample obtained 8 h after a dose, as opposed to both trough and peak samples, is evaluated here. Serum kinetics of netilmicin were studied prospectively in 51 adult patients with initial serum creatinine concentrations of < 130 mumol/L who were treated with a median daily dosage of 400 mg. Concentrations measured 8 h after administration were within the target range of 1.5-6 mg/L in 113 of 134 dosing intervals studied. Concentrations above and below this range correlated significantly with higher and lower 24-h trough concentrations and areas under the curve respectively. There was also a significant correlation between 8-h netilmicin concentrations and nephrotoxicity (P < 0.05); a relative increase of > or = 25% in the serum creatinine concentration or an absolute increase of > 25 mumol/L was detected in 0 of 7 patients with an 8-h concentration of < 1.5 mg/L, in 3 of 33 patients (9.1%) with an 8-h concentration of 1.5-6 mg/L and in 4 of 11 patients (36%) with an 8-h concentration of > 6 mg/L.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗