Venipuncture has been reported to be the most common painful event for a hospitalized child (1). Pain and fear associated with this seemingly trivial procedure often assumes disproportionate magnitude, especially in children. The percentage of pediatric patients experiencing acute behavioral distress while undergoing routine venipuncture has been reported to range from 28% to 83% (2). Methods such as application of EMLA cream, ethyl chloride spray, distraction tactics, and cough tricks have been used to minimize venipuncture pain (3–6). Valsalva during venous cannulation has been reported to be effective for reducing venipuncture pain in adults (7). Inflation of a balloon by a pediatric patient during venipuncture may result in a Valsalva maneuver and thereby decrease pain. In addition, balloon inflation may also act as a distraction. The present study was therefore designed to evaluate the efficacy of balloon inflation on venipuncture pain in pediatric patients.
After obtaining approval of the institute’s ethical committee and written informed consent from parents; 75 consecutive children (6–12 yr), ASA physical status I–II, undergoing various routine surgical procedures, were included in this prospective, randomized study.
Seventy-five consecutive pediatric patients were randomized with a computer generated table of random numbers into 3 equal groups of 25 each. Group I (control) patients did not press a rubber ball nor were they asked to inflate a balloon; Group II (distraction) patients were given a rubber ball (which produces a squeaky sound on being compressed) in the palm of their hand which was not to be cannulated. The patients were asked to alternately compress and release the ball; Group III (balloon) patients were asked to inflate a balloon at least for 20 s before initiation of the venipuncture. The cannula insertion was performed during the act of forceful expiration.
Children with delayed milestones, cardiac or neurological impairment, or failure to cannulate on the first attempt were excluded from the study. During preoperative visits the same anesthesia registrar (RSS) explained the procedure to the children and their parents and also taught them how to rate venipuncture pain. Patients were premedicated with syrup promethazine hydrochloride 0.5 mg/kg 2 h before venipuncture. Children were accompanied by their mothers in the preoperative area where the venipuncture was performed. Anxiety of each child at arrival in the preoperative area was rated by the Yale preoperative anxiety scale (0–100 scale) (8). The children were calmed throughout by the same anesthesia registrar (RSS) who also demonstrated to the children how to press on the rubber ball and how to inflate the balloon.
Depending on age a patient was either sitting in his/her mother’s lap or was asked to sit on a preoperative bed. A vein on the dorsum of the nondominant hand was identified and patients were asked to turn their head to the opposite direction. Then, depending on group allocation, patients were asked to inflate a balloon, press the rubber ball or were advised to do nothing. A small plastic hollow pipe was attached to the end of the balloon from where it is inflated and fixed to make the assembly easier to hold with one hand, thus making the act of inflation easier. Throughout the study period whenever patients were handed a rubber balloon to inflate they were always under the supervision of an anesthesia registrar (RSS) and a staff nurse. After 20 s of forced exhalation a manual venous tourniquet was applied and peripheral venous cannulation was attempted. Peripheral venous cannulation with a 22-gauge cannula (Angiocath SP™; Becton Dickinson India Ltd.) was performed by the same anesthesia registrar in all patients. Assessment of pain during venipuncture was done by using a 10-cm visual analog scale (VAS). This scale was placed on the back of the pain face scale, a scale which displays a sequence of faces ranging from a pleasant facial expression on one end to a highly distressed facial expression on the other end (9). Children were asked to place the sliding marker between these two extreme facial expressions indicating the degree of pain experienced during venipuncture. VAS scores of 1–3 were rated as mild, 4–6 as moderate, and >6 as severe.
The incidence of pain was compared with a z-test. Nonparametric data such as severity of pain (mild, moderate, and severe) were calculated with Fisher’s exact test. For comparison of VAS scores the Mann-Whitney test was used. The package SPSS 9.0 (SPSS Inc., Chicago, IL) was used for statistical analysis. P < 0.05 was considered as significant. Presuming that inflation of balloon during venipuncture would reduce venipuncture pain by 40%; power analysis, with α = 0.05, β = 0.95, showed that we would need to enroll 25 patients in each group.
This study was conducted from January 1, 2005 to July 31, 2005. There was no difference in demographic profile and preoperative anxiety levels among the groups (P > 0.05) (Table 1). Significant reduction in VAS was observed in the distraction and the balloon groups compared with the control group (Fig. 1). VAS in the balloon group was reduced compared with the distraction group (Fig. 1) (P < 0.05). The incidence of venipuncture pain in the control group and in the distraction group was 100% (25/25) and was reduced to 56% (14/25) in the balloon group (P < 0.05) (Table 2). A significant reduction in pain severity was observed in the distraction and balloon groups compared with the control group (P < 0.05) (Table 2). All patients in the balloon group who had pain (100%, 14/14) reported mild pain. In the distraction group 80% (20/25) of patients reported mild pain and the remaining 20% (5/20) had moderate pain. In the control group 64% (16/25) and 36% (9/25) of patients reported mild and moderate pain, respectively. No significant association was observed between sex and venipuncture pain in any of the groups (P > 0.05). We did not encounter any incidence of latex allergy in any of our patients.
The results of the study suggest that inflation of a balloon during venipuncture reduces both the incidence and severity of pain. Distraction, per se, does not reduce the incidence of venipuncture pain but is effective in reducing its severity.
Agarwal et al. (7) observed a reduction in the incidence and severity of venipuncture pain in adults after the Valsalva maneuver. They observed a reduction in the incidence of venipuncture pain to 72% as compared with 56% in their balloon group. Balloon inflation may have a combined effect (Valsalva and distraction) on decreasing the incidence of venipuncture pain.
The Valsalva maneuver is performed by having the subject conduct a maximal, forced expiration against a closed glottis and hold it for at least 16 seconds (10). Similar changes occur whenever a person conducts forced expiration against either a closed glottis or high pulmonary outflow resistance or when the thoracic and abdominal muscles are strongly contracted as occurs when inflating a balloon. This increase in intrathoracic pressure results in compression of the vessels within the chest and in turn results in baroreceptor activation. Activation of either the cardiopulmonary baroreceptor reflex arc or the sino-aortic baroreceptor reflex arc induces antinociception (11,12). In addition, the increase in intrathoracic pressure results in a decrease in venous return (12), thus making the veins more prominent and easier to cannulate (7).
Distraction has been used for reducing distress during venipuncture (13). Distraction is basically a cognitive behavioral preparation that may be active or passive; e.g., cough tricks, counting, blowing, playing music. Distraction may reduce attention by competing with alternative stimuli over the limited capacity of attention for sensory stimuli (14). This shift in attention may affect pain sensation more than anxiety (15). During the act of balloon inflation, pediatric patients forcefully exhale against a pressure system, producing an effect similar to that of Valsalva along with distraction from their surroundings.
In addition to behavioral modalities, drugs have been used to reduce the pain of venipuncture. EMLA cream has been found to be effective in reducing the pain of venipuncture when applied to the skin. However, EMLA cream requires 60 minutes of application time, and the risk of methemoglobinemia is a possible disadvantage (16). Subcutaneous infiltration of local anesthetic requires an injection and therefore does not solve the problem in children (17). Nitrous oxide provides both anxiolysis and analgesia when administered before venipuncture. Although nitrous oxide allows more than one attempt for venipuncture, the need of a facemask and delivery system makes it unsuitable (3).
Venipuncture, although a minor procedure, can be painful and frightening to an awake pediatric patient. Perception of venipuncture pain is dependent on physiological and psychological factors. The psychological factor of fear secondary to unknown surroundings, unknown events, and anticipation of pain may alter the child’s response to pain. A painful experience during venipuncture might lead to significant negative consequences such as extreme anxiety and physiological responses during subsequent procedures (18).
Latex allergy is reported in 26% of pediatric patients; 17% of children have allergic reactions to latex balloons (19). Children with myelodysplasia or congenital urological anomalies are particularly susceptible to latex allergy (20,21). The most common first presentation of latex allergy is intraoperative anaphylaxis during a previous surgery. We were fortunate not to encounter any incidence of latex allergy in any of our patients. We suggest the use of latex-free balloons in further studies. Balloon aspiration resulting in death has been reported in children 6 years and older (22,23). The use of party balloons has also resulted in ocular trauma (24,25). In our study, patients were always under the supervision of an anesthesia registrar whenever they were handed a balloon. The likelihood of ocular trauma from rupture of a balloon was further minimized in our study because of a hollow plastic pipe fastened to the balloon, thus moving the balloon further away from the patients.
In summary, we observed that inflation of a balloon during venipuncture reduced both the incidence and severity of venipuncture pain in pediatric patients. The observed reduction in pain could be secondary to distraction along with the physiological effect of the Valsalva maneuver on pain. We therefore suggest that balloon inflation is a safe and effective method for reducing the incidence and severity of pain from venipuncture in pediatric patients.
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