Specific allergy to Penaeus monodon (seawater shrimp) or Macrobrachium rosenbergii (freshwater shrimp) in shrimp-allergic children.

BACKGROUND: Allergy to specific shrimp species has not been studied systematically by oral challenges. A comparison of allergy to different shrimp species, especially seawater or freshwater varieties treatment, would be useful in testing shrimp-allergic subjects. OBJECTIVE: The aim of the study was to identify cases of specific allergy to seawater shrimp, Penaeus monodon (Pm), or freshwater shrimp, Macrobrachium rosenbergii (Mr), among shrimp-allergic children. Comparisons of skin tests using commercial and crude shrimp extracts plus the prick-to-prick (PTP) method were investigated. METHODS: Sixty-eight children with a history of shrimp allergy and skin tests positive to shrimp were orally challenged to both shrimp species. Reactivity to skin prick tests using extracts of Pm (PmSPT), Mr (MrSPT), commercial shrimp (ComSPT), and PTP tests (PmPTP, MrPTP) was compared. RESULTS: Food challenges identified specific allergy to Pm and Mr in 17.65% and 23.53% of the subjects, respectively. Positive and negative challenges to both shrimp species were found in 47.06% and 11.76% of the subjects, respectively. Correlations between the mean weal diameter (MWD) from ComSPT-PmSPT, ComSPT-PmPTP, ComSPT-MrPTP, PmSPT-PmPTP and MrSPT-MrPTP, but not ComSPT-MrSPT, were observed. The MWD from PmSPT and PmPTP were significantly larger in patients with positive than negative challenges to P. monodon (P<0.05). There was a trend that MWD from MrSPT were larger in patients with positive than negative challenges to M. rosenbergii (P=0.058). In the Pm allergy group, PmSPT with an MWD of 30 mm provided 80% predictive probability for positive challenges. PmPTP and ComSPT with an MWD of 22.5 and 20 mm provided 95% predictive probability, respectively. In the Mr allergy group, MrSPT with an MWD of 30 mm provided 95% predictive probability. CONCLUSION: Specific allergy to Pm or Mr was confirmed by food challenges. SPT using crude extracts and the PTP test are useful tools for screening shrimp sensitization before a food challenge. The predictive probability of SPT is helpful where a food challenge is not feasible.

Neodymium:YAG laser damage threshold of foldable intraocular lenses.

PURPOSE: To determine the energy level of the neodymium:YAG (Nd:YAG) laser that induced a 50% incidence of intraocular lens (IOL) damage in 5 foldable IOL materials. SETTING: Department of Ophthalmology, Siriraj Hospital Mahidol University, Bangkok, Thailand. METHODS: To simulate the condition within the capsular bag, an IOL was sandwiched between 2 rubber membranes. The front membrane had a central opening mimicking the anterior capsulotomy; the back membrane acted as the posterior capsule. The model was submerged in a water-filled chamber. The Nd:YAG laser with an automatic focus 150 microm beyond the focus of the aiming beam was used to perform a posterior capsulotomy. Three IOLs of each of 5 foldable IOL materials were tested. One type of poly(methyl methacrylate) (PMMA) was studied as a reference. The incidence of IOL damage at various energy levels was recorded. Linear regression analysis was used to determine the 50% incidence damage threshold. RESULTS: The 6 materials tested included 1 silicone lens (SI-40NB, AMO), 1 hydrophobic acrylic lens (MA60BM, Alcon), 3 hydrophilic acrylic lenses (Haptibag Ang, IOLtech; ACR6D, Corneal; H60M, Bausch & Lomb), and 1 PMMA lens (LX10BD, Alcon). The 50% incidence damage threshold values were 0.37 mJ, 0.54 mJ, 0.58 mJ, 0.52 mJ, 0.66 mJ, and 0.68 mJ, respectively. CONCLUSIONS: The 50% incidence damage threshold in all the IOLs was below the energy level normally used to perform a posterior capsulotomy in clinical practice. However, setting the laser at the lowest possible energy, focusing the laser beam beyond the posterior capsule, and performing the capsulotomy early should minimize the risk of IOL damage.

APACHE II in a postoperative intensive care unit in Thailand.

In order to evaluate the effectiveness of an intensive care unit (ICU), the case-mix has to be considered. This was a cohort study. By using Acute Physiology and Chronic Health Evaluation scores (APACHE II score), we evaluated the case-mix and mortality rate of 282 patients who were treated in our postoperative ICU. The overall mortality rate was 10.6 per cent. Higher Acute physiology scores and emergency surgery in the presence of chronic health status were related to higher mortality, but age was not. However, the original APACHE II model could not precisely predict the mortality of Thai patients. We used stepwise logistic regression to determine the predictors of death and found the prediction model to be -7.24 + 0.37 (APACHE II score) + 1.46 (postemergency surgery). The actual mortality for patients with APACHE II score > 15 in our ICU was higher than that predicted by the original APACHE II model. The causes of this difference might be difference in methodology, characteristics of ICU and the quality of care.

Cost-effectiveness analysis of patient-controlled analgesia, intramuscular q.i.d. injection and p.r.n. injection for postoperative pain relief.

We conclude that the intravenous PCA method is a cost-effective technique. Although the PCA device is expensive, the cost-effectiveness analysis should give explicit figures for physicians and the hospital administrators to decide whether they should use the PCA instead of the conventional method.

Patient-controlled analgesia in Thai patients.

We conclude that the intravenous PCA method is acceptable, easy to use, does not depend on the patients' level of education, and is safe for Thai patients. The average pain scores at 48 hours postoperation of the PCA group was significantly lower than for the conventional and the I.M. groups. Satisfaction was quite difficult to assess. Thai culture might influence how much pain is accepted and the patients had not experienced other techniques, so they could not make a comparison. The amount of morphine used by the PCA group was intermediate between that used by the other two groups.