bilization but it is still unclear which situations areprone to favour PA. Risk factors for PA includeperipheral circulatory failure, such as hypotension sec-ondary to dehydration or massive blood loss.Endotracheal intubation and intraoperativeTrendelenburg position have also been implicated.2–5

However, none of these risk factors were present inour patients.

In summary, we describe three LDLT donors whodeveloped occipital PA. Clinicians should be awarethat LDLT surgery may be associated to PA.However, the reasons for this potential associationremains obscure.

Toshiya Tomioka MD

Masakazu Hayashida MD

Kazuo Hanaoka MD

Tokyo, Japan

RReeffeerreenncceess1 Abel RR, Lewis GM. Postoperative (pressure) alopecia.

Arch Dermatology 1960; 81: 72–80.2 Lawson NW, Mills NL, Ochsner JL. Occipital alopecia

following cardiopulmonary bypass. J ThoracCardiovasc Surg 1976; 71: 342–7.

3 Patel KD, Henschel EO. Postoperative alopecia. AnesthAnalg 1980; 59: 311–3.

4 Wiles JC, Hansen RC. Postoperative (pressure) alope-cia. J Am Acad Dermatol 1985; 12(1 Pt 2): 195–8.

5 Calla S, Patel S, Shashtri N, Shah D. Occipital alopeciaafter cardiac surgery (Letter). Can J Anaesth 1996; 43:1180–1.

The relaxing effect of negative air ionson ambulatory surgery patients

To the Editor:Negative air ions are natural components of atmos-pheric air, which exist in a good quality environmentand are considered to have beneficial biologicalactions.1 Of these, a relaxing effect, for exampledecreases of anxiety, depression, irritability and tense-ness, has been demonstrated,2–4 whereas positive airions have an opposite effect.5 There are two methodsto generate negative ions: coronal discharge and watershearing. The latter method is, essentially, a naturalsource of negative ions.1 Whether negative ions exerta relaxing effect was examined in ambulatory surgerypatients.

After approval by our Institutional Committee, 95patients receiving a minor skin surgery of short dura-

tion with local anesthesia alone were allocated, onalternative weeks, to a regular environment (n = 44)or a negative ion-rich environment (n = 51). A com-mercially available appliance for generating negativeions by means of water shearing (Aqua Air Rich,Matsushita Seiko, Osaka, Japan) was operated in theoperating room (OR; 30 m3). An ion detector (IonTester KST-900, Kobe Denpa, Kobe, Japan) showedapproximately 1000 parts/mL of negative ions andzero parts/mL of positive ions. In the regular ORenvironment, it showed a level of zero for both ions.The temperature and humidity of the room were mea-sured by a digital thermohygrometer. Patientsreceived no premedication and fluid infusion, andwere asked by blinded nursing personnel to gradetheir degree of tension as: 1 = relaxed; 2 = normal ten-sion; 3 = mild tension; 4 = moderate tension; and 5 =severe tension, before entering the OR. After leavingthe OR, the same nurse asked the degree of tensionduring the first or latter half of the surgery.

There was no statistical difference between groupswith regard to age (37 ± 18, 43 ± 20 yr), male/femaleratio (17/27, 23/28), height (159 ± 16, 160 ± 9 cm),weight (59 ± 21, 57 ± 8 kg), room temperature (25.6± 1.4, 26.0 ± 1.3°C) and humidity (38.7 ± 9.2, 40.6± 12.0%), expressed as the mean ± SD or number. The

CORRESPONDENCE 187

FIGURE Degree of tension during the perioperative period.Values are mean ± SD. Statistical analysis was performed by theFriedman test followed by the Wilcoxon signed-rank test withBonferroni correction (*P < 0.05 vs before entering the operatingroom), and Mann-Whitney U test at each evaluated time.

degree of tension decreased significantly and morerapidly in the negative ion-rich environment (Figure).

The results suggest that negative ions produced bywater shearing have a relaxing effect in the OR envi-ronment. Some air conditioners producing negativeions have been developed recently. They may be use-ful in the hospital to reduce the patients’ psychologi-cal tension or anxiety.

Hiroshi Iwama MD

Hiroshi Ohmizo DDS

Shinju Obara MD

Aizuwakamatsu, Japan

RReeffeerreenncceess1 Iwama H, Ohmizo H, Furuta S, et al. Inspired super-

oxide anions attenuate blood lactate concentrations inpostoperative patients. Crit Care Med 2002; 30:1246–9.

2 Buckalew LW, Rizzuto A. Subjective response to nega-tive air ion exposure. Aviat Space Environ Med 1982;53: 822–3.

3 Livanova LM, Levshina IP, Nozdracheva LV, ElbakidzeMG, Airapetyants MG. The protective effects of nega-tive air ions in acute stress in rats with different typo-logical behavioral characteristics. Neurosci BehavPhysiol 1999; 29: 393–5.

4 Nakane H, Asami O, Yamada Y, Ohira H. Effect ofnegative air ions on computer operation, anxiety andsalivary chromogranin A-like immunoreactivity. Int JPhychophysiol 2002; 46: 85–9.

5 Giannini AJ, Castellani S, Dvoredsky AE. Anxietystates: relationship to atmospheric cations and sero-tonin. J Clin Psychiatry 1983; 44: 262–4.

Clonidine attenuates the hemodynamicresponses to hypercapnia during propo-fol anesthesia

To the Editor:Clonidine, an alpha2-adrenergic agonist, is widely usedas an anesthetic adjuvant,1,2 and is reported todecrease sympathetic nervous activity,2,3 plasma nor-epinephrine concentration,2 and sympathoadrenalresponses.2,3 Propofol can cause hypotension andbradycardia via a profound decrease in sympathetictone.4 The purpose of our study was to examine thehemodynamic changes to hypercapnia during propo-fol and isoflurane anesthesia, and to compare them inthe presence and absence of clonidine premedication.

After obtaining approval from our institutionalHuman Investigation Committee and informed con-sent from each patient, 60 adult patients (ASA physi-cal status I) were randomly assigned to one of twogroups. Thirty patients received famotidine 20 mg(control group) orally 90 min before the induction ofanesthesia, whereas the remaining 30 patients receivedclonidine 5 µg·kg–1 and famotidine 20 mg (clonidinegroup). General anesthesia was induced with ivpropofol 2 mg·kg–1, and tracheal intubation was facil-itated with iv vecuronium 0.2 mg·kg–1. In 15 patientsin each group, anesthesia was maintained with isoflu-rane 1% (end-tidal) in oxygen, and in the other 15patients with iv propofol 100 µg·kg–1·min–1 duringventilation with oxygen. The baseline measurementsincluding mean arterial pressure (MAP), heart rate(HR), cardiac index (CI), and plasma catecholamineconcentration were made during normocapnia (an

188 CANADIAN JOURNAL OF ANESTHESIA

FIGURE Difference from normocapnic values of mean arterialpressure (MAP), heart rate (HR) and cardiac index (CI) duringhypercapnia (PaCO2 = 55 mmHg). Values are mean ± SD. *P <0.05 vs normocapnic value. †P < 0.05 vs the other three sub-groups.