ERYTHROMYCIN REDUCES COLD-RELATED COPD EXACERBATIONS

A prospective, randomized, controlled trial has evaluated erythromycin’s efficacy in lowering the incidence of the common cold and cold-induced exacerbations of respiratory difficulties in patients with chronic obstructive pulmonary disease (COPD).

Erythromycin was found to have beneficial effects after 109 patients with COPD were randomized in September 1997 to receive either the drug (55 patients) or no active treatment (54 patients). Follow-up began one month later and continued for one year. Cold symptoms, such as sneezing, nasal discharge, nasal congestion, malaise, headache, chills, feverishness, sore throat, hoarseness, and cough, were individually rated on a severity scale ranging from 0 to 3. A cold was diagnosed when a patient had a total symptom score above 5. COPD exacerbations were defined as worsening of COPD symptoms severe enough to require a change in therapy.

The two groups of patients were similar in baseline characteristics, including pulmonary function test results. During follow-up, there was an average of 1.24 colds per person in the erythromycin group, compared with 4.54 in the control group. Overall, the proportions of patients experiencing exacerbations in the erythromycin and control groups were 11% and 56%, respectively. However, the proportion of colds resulting in COPD exacerbations was similar (21% vs 26%, respectively).

Because of the risk of the emergence of erythromycin-resistant organisms, the researchers suggested that this treatment be reserved only for those patients at high risk for COPD exacerbations. However, their results show that the efficacy of low-dose erythromycin in reducing cold frequency and COPD exacerbations is not in doubt.

Suzuki T, Yanai M, Yamaya M, et al. Erythromycin and common cold in COPD. Chest. 2001;120:730-733.

OBSTRUCTIVE SLEEP APNEA COMPLICATES SURGICAL OUTCOMES

Obstructive sleep apnea syndrome (OSAS) is a risk factor for postoperative morbidity in patients undergoing hip or knee replacement.

A recent case-control study compared 101 such patients with OSAS against 101 controls without the condition. In 36 cases, the operation was performed within three years before OSAS diagnosis; in the other 65 cases, it was done afterwards.

Complications of any type developed in 39 of the OSAS patients and in 18 of the controls. Serious complications developed in 24 and nine patients, respectively. Furthermore, the study authors determined that hospital stays were longer for patients with OSAS than for those without it: 6.8 days versus 5.1 days, respectively.

The researchers opined that airway obstructions are common in joint replacement patients with OSAS because of the postoperative requirement that such patients remain supine, which has been shown to double a patient’s respiratory distress index. Another aggravating factor may be the postoperative use of intravenous narcotics, which could aggravate respiratory complications in patients with OSAS.

Furthermore, the investigators stated that most complications occurred in the 24 hours immediately after surgery, suggesting that the sedatives, anesthetics, and narcotics administered during that period could increase upper airway resistance by relaxing upper airway dilator muscles. The fact that patients using continuous positive airway pressure at home before surgery experienced fewer complications than did the other patients with OSAS led the investigators to question whether early intervention for such patients might be associated with better outcomes.

Gupta RM, Parvizi J, Hanssen AD, Gay PC. Postoperative complications in patients with obstructive sleep apnea syndrome undergoing hip or knee replacement: a case-control study. Mayo Clin Proc. 2001;76:897-905.

CAN OXYGEN PREVENT CNS EVENTS IN SICKLE CELL PATIENTS?

Could nocturnal oxygen supplementation be an alternative to blood transfusion for preventing cerebral complications in patients with sickle cell disease? The underlying physiologic rationale for this hypothesis is that nocturnal breathing disorders can induce hypoxemia, which, in turn, promotes polymerization of sickle hemoglobin, as well as the adhesion of red cells and platelets to vascular endothelium.

To investigate this issue, Kirkham et al studied 95 patients with sickle cell disease with overnight oximetry and transcranial Doppler sonography. The patients, none of whom had previously experienced a stroke, ranged in age from 1 to 23 years.

During a median follow-up of six years, 19 patients suffered a central nervous system (CNS) event: seven had strokes, eight had transient ischemic attacks, and four had seizures.

Three variables—low mean overnight oxygen saturation (SaO2), high internal carotid or middle cerebral artery blood velocity, and high hemoglobin concentration—were independently associated with time to onset of a CNS event. In patients with an SaO2 of 96% or higher, there was little risk of a CNS event. In contrast, in patients with an SaO2 below 96%, the hazard ratio was 5.6.

Kirkham et al speculate that nocturnal oxygen supplementation could be less expensive and safer than blood transfusion for the prevention of CNS events in patients with sickle cell disease. A controlled trial is being conducted to evaluate the efficacy of this approach.

Kirkham FJ, Hewes DKM, Prengler M, et al. Nocturnal hypoxaemia and central-nervous-system events in sickle-cell disease. Lancet. 2001;357:1656-1659.

FEVER A POOR INDICATOR OF FLU ONSET IN ELDERLY

Symptoms of influenza in the elderly may not include fever, according to research presented at the American Geriatrics Society 2001 Annual Scientific Meeting. Furthermore, the flu symptoms that do appear may do so gradually, unlike the way they manifest in younger patients.

In two studies, Vij et al examined the symptoms exhibited by 125 elderly patients; of these, 30 had culture-confirmed influenza A, 66 had influenza B, and 29 had respiratory syncytial virus (RSV). The authors noted that only 26%, 38%, and 31% of these patients, respectively, had had a temperature above 37.2°C (99°F) when symptoms first appeared.

A more prevalent indicator of flu infection on the day of symptom onset was cough, which appeared in 76% of the patients with influenza A, 55% of those with influenza B, and 52% of those with RSV. Within 48 hours of symptom onset, auscultative findings were present in 83%, 33%, and 69% of patients, respectively.

The investigators concluded that the lack of fever was likely attributable to elderly persons’ reduced capacity for thermoregulation. This would make fever a less reliable sign of underlying problems. They also said that attention to cough and chest sounds would be more important during the early stages of suspected flu. Such attention would presumably increase the likelihood that treatment could be provided in the most critical 48-hour period after flu onset.

Vij S, Gravenstein S, McElhaney J, et al. Influenza B presentation in elderly patients. Presented at: American Geriatric Society 2001 Annual Scientific Meeting; May 11, 2001; Chicago.
Vij S, Gravenstein S, McElhaney J, et al. Presentation of RSV and influenza in the elderly population. Presented at: American Geriatric Society 2001 Annual Scientific Meeting; May 11, 2001; Chicago.

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