Dario Galante

Preoperative apnea in a preterm infant after caudal block with ropivacaine and clonidine

mandatory? Anesth Analg 2004; 98: 102–106. 2 de Ruiter J, Crawford MW. Dose–response relationship and infusion requirement of cisatracurium besylate in infants and children during nitrous oxide-narcotic anesthesia. Anesthesiology 2001; 94: 790–792. 3 Tobias JD, Lynch A, McDuffee A et al. Pancuronium infusion for neuromuscular block in children in the pediatric intensive care unit. Anesth Analg 1995; 81: 13–16.

Intraoperative hypothermia. Relation between general and regional anesthesia, upper‐ and lower‐body warming: what strategies in pediatric anesthesia?

It is well recognized that anesthetics (including regional anesthesia) have negative effects on the ability to maintain body temperature, although the mechanisms by which the different classes of drugs do this, vary. The result is a poikilothermic response, in which the body temperature declines passively towards the ambient temperature. There are numerous deleterious effects of hypothermia, including impairment of coagulation and platelet function, decreased action of various enzyme systems and drug metabolism, prolonged postanesthesia unit stay, increased wound infection rate and cardiac arrhythmias (1). Severe hypothermia tends to occur more often in a low-ambient operating room (OR) temperature, burn injuries, large blood loss, general anesthesia with neuroaxial anesthesia, cold i.v. fluid, cold inspired gas by mechanical ventilation and associated with thoracic, abdominal and vascular surgery. Infants and neonates have a higher risk of developing intraoperative hypothermia (2). Pediatric patients are particularly susceptible to developing hypothermia in the OR (core temperature £ 36.0 C). Their regulatory capacity is less effective than in adults. They have a reduced weight-to-surface-area ratio, increased heat loss from the head (thin skull and scalp), and limited stores of subcutaneous fat. Pediatric patients seldom shiver and to restore normothermia, they increase metabolism of brown fat (nonshivering thermogenesis), thus increasing oxygen consumption. In order to maintain body temperature during surgery, either passive or active heating methods can be employed such as forced air warming, circulating water mattresses, radiant heaters, counter-current fluid warmers, insulation and increasing environmental temperature. During general anesthesia, thermoregulation develops in three phases: internal redistribution of heat, heat loss to the environment and thermoregulatory response to prevent hypothermia (plateau or rewarming) (3). The phases of internal redistribution cannot be controlled during anesthesia. Phase 1: The initial rapid decrease in temperature is from the vasodilatory effects of anesthetics and is related to internal redistribution of heat from the central core to the peripheral compartment. This effect is mainly noted in the hands and feet because of residing thermoregulatory arteriovenous shunts. Phase 2: In the second and third hour of anesthesia, a progressive and attenuated phase of temperature drop occurs representing a greater amount of heat lost via convection, conduction, evaporation and radiation. Phase 3: More than 3 h following anesthesia induction we observe a plateau phase in which core temperature remains hypothermic but stable because of active thermoregulatory peripheral vasoconstriction. The rapid reduction in core temperature (phase 1) is very important for brief surgical procedures because 1 ± 2 C are lost within a relatively short time. Correspondence to: Dario Galante, Responsible for Pediatric and Neonatal Anesthesia, University Department of Anesthesia and Intensive Care, University Hospital Ospedali Riuniti , Foggia, Italy (email: dario.galante@tin.it). Pediatric Anesthesia 2007 17: 821–823 doi:10.1111/j.1460-9592.2007.02248.x

Hemodynamic effects of levobupivacaine after pediatric caudal anesthesia evaluated by transesophageal doppler.

Background:  The aim of this study is to determine if there are significant differences in hemodynamic effects between combined general‐regional anesthesia using levobupivacaine 0.25% 2 ml·kg−1 via the caudal route in comparison with balanced general anesthesia using continuous infusion of remifentanil in young children undergoing genitourinary surgery.

Correlation of bispectral index (BIS) monitoring and end-tidal sevoflurane concentration in a patient with lobar holoprosencephaly

OBJECTIVE The bispectral index (BIS) is a parameter derived by electroencephalography (EEG) which provides a direct measurement of the effects of sedatives and anesthetics on the brain and offers guidance on the adequacy of anesthesia. The literature lacks studies on BIS monitoring in pediatric patients with congenital brain disease undergoing general anesthesia. CLINICAL FEATURES A 13-year-old child weighing 32kg, suffering from lobar holoprosencephaly, underwent surgery in which the bispectral index (BIS) monitoring the depth of anesthesia showed an abnormal response. Detailed analysis of the trends of BIS values in the different observation times demonstrated sudden falls and repetitive values of BIS likely related to repetitive epileptiform electrical activity caused by sevoflurane. CONCLUSION The BIS is a very useful monitoring tool for assessing the degree of depth of anesthesia and to analyze the electroencephalographic variations of anesthetics. Particular attention should be given to patients with congenital disorders of the central nervous system in which the BIS may give abnormal responses that do not reflect an accurate assessment of the depth of anesthesia.

Anesthetic management of children with pulmonary arterial hypertension

We read with interest the study by Heard et al. of dexmedetomidine for pediatric MRI sedation: a review of a series of cases (1). We noted an error in Table 1 in the study mentioned that we would like to point out. The authors listed the cost of dexmedetomidine as

Correlação entre monitoração do índice bispectral (BIS) e concentração expirada de sevoflurano em paciente com holoprosencefalia lobar

55 for a 100-lg vial. The only preparation for dexmedetomidine available in the US is a 2-ml vial of 100 lg ⁄ mL for a total of 200 lg vial (2). As per the authors’ calculations, this would reduce the cost per case of dexmedetomidine from

Cuffed and Uncuffed Tubes and the Geometric Correlation with Pediatric Airway

15.40 to

The use of ultrasound guidance to avoid the pinch-off syndrome

7.70. Instead of dexmedetomidine being similar to propofol in cost per case, it would be approximately half the cost of propofol. We do acknowledge that this would not change the ampule cost per case though. Lastly, we would like to point out a typo in the spelling of the first author’s name in reference 5 of the study; it was printed as (Shurky) and the correct spelling is (Shukry). Mohanad Shukry M D* Philip Kalarickal M D M P H† *Department of Anesthesiology, Children’s Hospital of Oklahoma, Oklahoma City, OK, USA †Department of Anesthesiology, Tulane University Hospital and Clinic, 1415 Tulane Ave. SL-4, New Orleans, LA, USA (email: mohanad-shukry@ouhsc.edu)

Bilateral ultrasound transversus abdominis plane block in a patient affected from Menkes disease

OBJECTIVE The bispectral index (BIS) is a parameter derived by electroencephalography (EEG) which provides a direct measurement of the effects of sedatives and anesthetics on the brain and offers guidance on the adequacy of anesthesia. The literature lacks studies on BIS monitoring in pediatric patients with congenital brain disease undergoing general anesthesia. CLINICAL FEATURES A 13-year-old child weighing 32kg, suffering from lobar holoprosencephaly, underwent surgery in which the bispectral index (BIS) monitoring the depth of anesthesia showed an abnormal response. Detailed analysis of the trends of BIS values in the different observation times demonstrated sudden falls and repetitive values of BIS likely related to repetitive epileptiform electrical activity caused by sevoflurane. CONCLUSION The BIS is a very useful monitoring tool for assessing the degree of depth of anesthesia and to analyze the electroencephalographic variations of anesthetics. Particular attention should be given to patients with congenital disorders of the central nervous system in which the BIS may give abnormal responses that do not reflect an accurate assessment of the depth of anesthesia.

Remifentanil infusion reduces desflurane airway irritation via proseal laryngeal mask in children.

To the Editor: We read with great interest the article by Litman1 concerning the problems surrounding the choice of cuffed and uncuffed tracheal tubes in anesthesia and pediatric intensive care. Although the issue has been on debate for many years and now there is a general belief that cuffed tubes can also be safely used in children, I think it is important to make some reflections on the strict geometrical relationship between tracheal tubes and the anatomy of the cricoid and trachea. Both Litman and Weiss2,3 have frequently reported and demonstrated that the cricoid lumen is not circular but rather of an ellipsoidal shape. By performing investigations with nuclear magnetic resonance, Litman has shown that the cricoid ring in its cross section is narrower than the anteroposterior section. This finding is, in our opinion, of considerable clinical importance and should not be overlooked. Considering that the orotracheal tubes have a perfectly circular shape, they are ill-adapted within an ellipsoidal structure. If we try to draw a circle inside an ellipse, imagining that the circle represents the tube and the ellipse is the cricoid, we can easily demonstrate that the tracheal tube, even if the proper size, can apply excessive pressure on cricoid structures along the minor axis of its elliptical shape. At the same time, the tube would not adhere well to the lateral areas of the cricoid corresponding to the major axis of the ellipse. This circumstance, in the presence of uncuffed tubes, creates the condition for an imperfect seal in the tube airway system with an increased risk of microinhalation, loss of gas, requiring repeated adjustments of mechanical ventilation parameters. Another risk present is the excessive movement of the tube and its tip with In Reply: We thank Dr. Eisenkraft for taking the time to write regarding our recent article1 and describe to us a detailed alternative scheme by which expiratory limb ventilation can be provided. The suggestion is valid and not the one that we thought of in this emergency. We were unaware of the Kummar et al. description, which does not explain how the Bain circuit was pressurized on his Aisys machine (GE Healthcare, Madison, WI). Dr. Eisenkraft’s alternative demands mental preparation for such emergencies, just as we taught our option in previous simulations, and would require that the clinician recall the alternate common gas outlet circuitry immediately within a crisis situation. Although we admire his technically accurate methods of scavenging the volatile agent, we believe that such connections would not be available or clinically necessary in a brief emergency situation. From a technical perspective, we would like to raise three issues with his alternative.