Rationale:

• Plasma leakage is the hallmark of severe dengue, and appropriate fluid replacement is the cornerstone of management.
• The clinical course of dengue hemorrhagic fever is rather stereotypic. It usually begins abruptly and has three phases: febrile (fever plus other features of classic dengue), critical (platelet count <100 × 10⁹/L or hematocrit >20% from baseline), and convalescent (signs of recovery).
• Plasma leakage in patients with dengue hemorrhagic fever occurs only during the critical phase, which lasts 24 to 48 hours after onset. Intensive and appropriate fluid management is required during this period; however, caution must be exercised because excessive intravenous fluids given during this phase may cause fluid overload later in the illness.
• Invasive procedures may lead to severe bleeding in the presence of a coagulopathy.

Evidence:

• A randomized, double-blind trial comparing four intravenous fluid regimens for acute resuscitation of 50 children with dengue shock syndrome found that severely ill children with very narrow pulse pressures (<10 mm Hg) improved significantly more quickly if they immediately received a colloid solution. Colloids (dextran 70 or the protein digest gelafundin 35,000) restored the cardiac index and blood pressure and normalized the hematocrit more rapidly than crystalloids (Ringer's lactate or 0.9%-weight/volume saline). Dextran 70 provided the most rapid normalization of the hematocrit and restoration of the cardiac index. However, in children with circulatory compromise but higher pulse pressures (between 10 mm Hg and 20 mm Hg), no difference in outcomes was seen between those treated immediately with crystalloid solutions and those treated immediately with colloid solutions (97).
• A randomized, controlled trial of four different types of fluid (dextran, gelatin, Ringer's lactate, and normal saline) for initial resuscitation in 230 Vietnamese children with dengue shock syndrome (excluding those with severe bleeding manifestations) did not find a specific fluid type to be clearly advantageous; however, the longest recovery times occurred in the group receiving Ringer's lactate. The most significant factor determining clinical response was the pulse pressure at presentation. A comparison of the colloid and crystalloid groups suggested benefits in children presenting with lower pulse pressures who received one of the colloids. Allergic reactions occurred in 5 of 51 children given 3% gelatin (98).
• In a randomized, double-blind comparison of three fluids for initial resuscitation of Vietnamese children with dengue shock syndrome, 383 children with moderately severe shock were randomly assigned to receive Ringer's lactate, dextran 70, or 6% hydroxyethyl starch. A total of 129 children with severe shock were randomly assigned to receive one of the colloids. Requirement for rescue colloid, the primary outcome measure, was similar for the different fluids in the two severity groups. Treatment with Ringer's lactate resulted in less rapid improvement in hematocrit and a marginally longer time for initial recovery than treatment with either of the colloid solutions. There were no differences in all other measures of treatment response (99).
• In a small, randomized study of patients with dengue shock syndrome complicated by respiratory failure, oxygen administration by nasal continuous airway pressure was a better option than oxygen administered by a face mask (95).
• A prospective, randomized study of 37 patients with dengue shock syndrome complicated by respiratory failure compared the effectiveness of oxygen treatment administered by a face mask vs. by nasal continuous positive airway pressure. Chest radiographs showed pleural effusions in 92% of patients and interstitial edema in 33%. After 30 minutes of treatment, the respiratory rate decreased significantly in the group receiving nasal continuous positive airway pressure (P<0.05), whereas SaO₂ and PaO₂ increased in both groups (P<0.01). Subsequently, the investigators found a significant difference in unresponsiveness to treatment between the two groups. Complications from nasal continuous positive airway pressure or oxygen mask treatment were not documented (100).
• WHO guidelines for management of dengue were first formulated in 1974 and were subsequently updated in 1986, 1994, and 1997 (55). The use of these guidelines, particularly intensive fluid replacement and monitoring, reduced case-fatality rates from approximately 20% to less than 1% in hospitals with facilities for intravenous resuscitation and monitoring (101). The guidelines have been modified for easier use by health care workers in small hospitals in developing countries (102).

Comments:

• The crystalloid solution must be isotonic.
• Volumes must be just sufficient to maintain effective circulation during the period of plasma leakage. Fluid rates should be reviewed every 1 to 3 hours. If the patient is in shock, this should be done at shorter time intervals.
• Nasal continuous positive airway pressure reduces the need for intubation and ventilation in patients with dengue shock syndrome and respiratory failure.