Indian J PhySiol Pharmacol 1999; 43 (2) : 263-266

LETTER TO THE EDITOR

NOISE IN THE OPERATION THEATRE: INTENSITY AND SOURCES

Sir,

(Received on January I, 1999)

In recent years the deleterious effectsof environmental noise on human health andwork performance has evoked considerableconcern 0-3). Prolonged exposure to loudnoise in daily life may act as a biologicalstressor leading to sustained activation ofthe autonomic nervous system and thepituitary adrenal axis with many farreaching physiological & psychologicaleffects (4). In hospital settings, the staff andpatient alike are also exposed to a barrageof sound (5). The operation theatres (aT) inparticular are as susceptible to noisepollution as other working environmentswith noise levels akin to those encounteredon a motorway (6). This noise has a dualeffect of impaired concentration &performance of the aT staff as well asincreased anxiety and discomfort Inconscious patients (7).

Studies on noise levels in aT have beenconducted in several countries (8, 9). In thisstudy, we measured the sound levels andidentified their sources, during a completesurgical procedure, Herniotomy, (underGeneral Anesthesia) in the Surgery aT ofthe Guru Teg Bahadur Hospital, Delhi. Wefound that despite technological advances,the noise levels are high, posing a potentialdanger to both the patient and the aT staff.

Sound levels were recorded using SoundLevel Meter (SLM) B & K 2209, Bruel and

Kjaer, Copenhagen with a 1/3 octave filterset Type 1616, a built in microphone and alinear display of noise intensity in decibels(dB). All measurements were made at slowresponse dB (A) scale. The SLM was placedon a stool, 0.5 meter above ground leveland 2 meters away from the head end ofthe operating table. It was kept switchedon during the entire period of observation.The recordings were made by two observersduring the pre-operative, operative andpost-operative phase of the surgicalprocedure. Similar recordings were alsotaken by them in the recovery room afterthe patient was shifted there. The aT staffwas kept uninformed about the kind ofrecordings being carried out to enable theobservations to be made without them beingconscious of the recording and thusinfluencing it in any way. Most noises wererepeated several times during the course ofthe observations and therefore their rangewas noted.

The main sources of noise in the aT atdifferent phases of the surgical procedureand their intensity, as observed, aresummarized in Table I.

Noise in the aT and recovery room wasfound to be above internationallyrecommended noise levels for hospitals. Theaverage noise level was in the range of 60-

264 Letter to the Editor

TABLE

Indian J Physiol Pharmacol 1999; 43(2)

Noise in the Operation Theatre and Recovery Room.

(1)

(2)

(3)

(4)

(5)

Source

During pre-operative phaseArranging instrument trolleyWheeling-in patient trolleyConversation among OT StaffInduction of anesthesiaMoving IN drip standMoving metal stoolsAnesthetic monitors (ECG, Pulse Oximeter)

During operative phaseGetting instruments from metal cansConversation among OT StaffShouting for assistanceChange of surgeonsDiscussion with consultantQuiet OT during surgeryHandling instrumentsUnwrapping instruments from wrapperOpenning steel cupboardsOpenning gas cylinderBanging of metal traysSuctionDiathermy alarmSterelizer whistle (adjacement room)Running water (adjacement room)Ventilator alarmDraping of patientNurse comes in for instruments from next OT

During post-operative phaseCounting and handling instrumentsPatient shifted to trolleyPatient wheeled outReversal of anesthesia (with suction, coughing)Quiet empty OTPreparation of next operation

In the Recovery RoomPatient moaningAir-conditioning (duct level)Conversation & general activityPatient trolley moving in corridor outsideTelephone ringer

Frequent noise during all phasesDoors slammingConversa tion

Intensity dB rAJ

68- 7078- 8466- 7062- 64688466- 70

75- 8062- 6872- 7865- 7068- 7458- 607565-70767072- 7466-708264- 6660- 6468-766268- 70

7268- 7078- 8464- 7445- 4752- 54

686460-707056

74- 8060- 70

Indian J PhysioI Pharmacol 1999; 43(2)

70 dB(A) with frequent increases of upto 84dB(A). The International Noise Council hassuggested that noise levels in acute areasin hospitals should not exceed, on average,45 dB(A) in the day time and 30 dB(A) atnight (10), while the US EnvironmentProtection Agency recommends noise levelsof 45 dB(A) in day time and 35 dB(A) atnight (1). The noisiest part of the surgicalprocedure recorded was the pre-operative(preparatory) phase and the post-operativephase when the patient was being wheeledout from the OT. Hodge et al (9) alsorecorded the loudest noises during thepreparation period of the operation.

Throughout the surgery there were loudintermittent noises which were bothpredictable, like the anesthetic alarms andunpredictable like the noise produced by theslamming of OT doors, other alarms and thehandling of instruments and equipment.There was constant to and fro traffic withpeople moving in 2.nd out of the OT atfrequent intervals (almost every 30 seconds)causing the heavy automatic doors of theOT to swing open or slam shut very noisily,thus disturbing j I,· surgeons. It has beenreported that a sudden (unpredictable) noisewith a level as little as 30 dB above thebackground level is likely to cause a startleresponse and subsequent stress re:1ction(12). This may reduce vigilance and impairconcentration during critical periods of th(:operation leading to reduced performance.

There ,was also incessant speechcommunction among the OT staff, some ofit being pertient, but most being inane, andthus avoidable. It has been observed thatmembers of a surgical team are more easilydistracted by conversation In the

Letter to the Editor 265

background than by other types of noise.Communication in the OT is essential if thesurgical procedure is to be carried outefficien tly and safely. The backgroundavoidable noise, including conversationcould lead to a masking effect making thevital communication difficult (13). The mainafter effects of long-term high intensitysounds is a loss of hearing and hypertension(14).

Noise is equally stressful to theconscious patient and adds to his anxiety.

IIn the OT, sudden loud noise mayprecipitate a startle response, causing bodyjerk, which could hamper the anesthetic orsurgical procedure. Noise in the recoveryroom, which during our study ranged from56-70 dB(A), may be an irritant to thepatient who is experiencing post operativepain (15). It may also interfere with sleepand the patient may be unable to adequatelyrest (6). The main sources of noise werepatient trolley, conversation between staffand the moaning of patients.

Thus we observed that in the OT andthe recovery room, the doors and equipmenttogether with the conversation among staffwere the major sources of noise. These canbe controlled to a considerable extent bybetter acoustic design of the areas discussed,better designing of the equipment as alsoits maintenance, together with education, agreater sensitivity and awareness of thestaff towards the problem, and the need tocontrol noise.

The authors wish to acknowledge andthank the assistance and coop(~rat.ion

extended by Shri P.S. Sunderam Chairmanand Managing Director, fi()actcast

266 Letter to the Editor

Engineering Consultants India Ltd., NewDelhi for generously lending the use of the

Indian J Physiol Pharmacol 1999; 43(2)

Sound Meter and access to its excellentlibrary facilities.

NILIMA SHANKAR* AND K. L. MALHOTRA**,*Department of Physiology,

UCMS & GTB Hospital, Delhi - 110 095and

**Jt. Secy., Acoustical Society of India, New Delhi.

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2. Carter NL, Hun Yor SN, Crawford G, Kelly D,Smith AJ. Environmental noise and sleep-a studyof arousal, cardiac arrhythmia and urinarycatecholomines. Sleep 1994; 17: 298-307.

3. Wu TN, Lai JS, Shen CY, Yu TS, Chang PY.Aircraft noise, hearing ability and annoyance. ArchEnviron Health 1995; 50: 452-456.

4. Biley FC. Effects of noise in hospitals. Br J Nurs;3: 110-113.

5. Shapiro RA, Baland T. Noise in the operating room.N Engl J Med 1972; 287: 1236-1237.

6. Davies JM, Ewen A, Cuppage A, Gilbert D,Winkelaar R. Noise levels in the operating rooms­a comparison of Canada and England. AnesthesiaIntensive Care 1989; 17: 98-99.

7. Sahoo GC. Noise pollution. J Indian Med Assoc1997; 95: 1-2.

8. Kam PCA, Kam AC. Thompson JF. Noise pollutionin the anesthetic and intesive care environment.Anesthesia 1994; 49: 982-986.

*Corresponding Author

9. Hodge B, Thompson JF. Noise pollution in theoperating theatre. Lancet 1990; 335: 891-894.

10. Bentley S, Murphy F, Dudley H. Perceived noisein surgical wards and intensive care area: anobjective analysis. Brit Med J 1977; 2: 1503-1506.

11. Environment Protection Agency Information onlevels of environmental noise requisite to protectpublic health and welfare with an adequate marginof safety. (Report No. 550-9-74-004), WashingtonDC, Government Printing Office, 1974.

12. Rylander R. Dancer A. Startle reactions tosimulated sonic booms: influence of habituation,boom level and background noise. J Sound Vib1978; 61: 235-243.

13. Ward WD. General auditory effects of noise.Otolaryn Clin N Am 1979; 12: 473-491.

14. Andren L, Lindstedt G, Bjorkman M, Borg KO,Hansson L. Effect of noise on blood pressure and'stress' hormones. Clin Sc 1982; 62: 137-141.

15. Minckley BB. A study of noise and its relationshipto patient discomfort in the recovery room. NursRes 1968; 13: 59-65.

16. Ward WD. Effects of high-intensity sound. InCrocher MJ eds. Encyclopedia of Accoustics 1997;1497-1507.

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