Cause of Device-Related Incident
Device factors; Support system failures; User errors

Clinical Specialty or Hospital Department
Anesthesia; CCU / ICU / NICU; Clinical/Biomedical Engineering; Obstetrics and Gynecology; OR / Surgery

Device Factors
Design / labeling error; Device failure; Device interaction; Improper maintenance, testing, repair, or lack or failure of incoming inspection; Manufacturing error

Document Type
Hazard Reports

Mechanism of Injury or Death
Burn (electrical, thermal, chemical)

Support System Failures
Use of inappropriate devices

User Errors
Failure to read label; Inappropriate reliance on an automated feature; Incorrect clinical use; Incorrect control settings

UMDNS
Electrodes, Electrosurgical [15-579]; Electrosurgical Units [11-490]; Germicides [18-159]; Hypo/Hyperthermia Blankets [12-067]; Hypo/Hyperthermia Units [12-068]; Lights, Examination [12-276]; Oxygen Monitors, Transcutaneous [12-592]; Pressure Pads [12-936]; Restraints [13-346]; Transilluminators [14-130]; Warmers, Radiant [13-248]

Skin Injury in the OR and Elsewhere



Hazard [Health Devices Oct 1980;9(12):312-8]

Problem

Despite a great deal of care and concern by medical, surgical, and engineering personnel, inadvertent skin destruction in the operating room and intensive care areas continues to occur. These injuries may lead to prolonged morbidity, extended hospitalization, and increased cost, in addition to damaging the patient's trust in the hospital and medical staff to the extent that legal redress is sought.

We receive an average of three reports per month involving skin destruction. The literature on this subject is rather scarce and fragmented. We believe that a comprehensive review of the mechanisms of such injuries will prove helpful in recognizing, investigating, and preventing them.

Discussion

While the usual appearance of intraoperative skin injury is that of a full- or partial-thickness burn, thermal or electrical sources are not always involved. It is therefore misleading (and in many cases inaccurate) to refer to an injury as a "burn." "Lesion" is a more appropriate term that allows the consideration of other causes. Descriptions of some major causative mechanisms follow.

Electical

Electrosurgery

ESUs frequently cause injuries in the operating room. Few surgical personnel understand the principles of operation of ESUs, and many are not fully aware of the necessary safety precautions. Following is a chronological list of Health Devices articles that address these issues:

ECRI. Electrosurgical units (Evaluation). Health Devices 1973; 2:184.

ECRI. Danger! Electrosurgical units at work (Hazard). Health Devices 1973; 2:218.

ECRI. Patient burns and ECG monitors. Health Devices 1973; 2:219.

ECRI. Electrosurgery and laparoscopy (Hazard). Health Devices 1973; 2:222.

ECRI. Disposable electrosurgical active handles (Evaluation). Health Devices 1973; 2:256.

ECRI. Disposable electrosurgical return electrodes (Evaluation). Health Devices 1973; 2:264.

ECRI. Incorrect connection of electrosurgical cables (Hazard). Health Devices 1974; 3:201.

ECRI. Electrosurgical units (Evaluation). Health Devices 1977; 6:59.

ECRI. Electrosurgical unit safety. Health Devices 1977; 6:119.

ECRI. Disposable electrosurgical return electrodes (Consultant's Corner). Health Devices 1977; 6:147.

ECRI. Disposable electrosurgical dispersive electrodes (Evaluation). Health Devices 1979; 8:43.

ECRI. Electrosurgical burns and laparoscopy. Health Devices 1980; 9:206.

The following works also originated at ECRI:

Knickerbocker GG. ESU safety: Purchasing, preventive maintenance, incident investigation. Medical Instrumentation 1980; 14(Sep-Oct):257.

Knickerbocker GG, Skreenock JJ. Electrosurgical equipment. In: Cook and Webster, eds. Therapeutic electrosurgery. Englewood Cliffs, N.J.: Prentice-Hall (accepted for publication in 1981).

Skreenock JJ. Electrosurgical quality assurance: The view from the OR table. Medical Instrumentation 1980;14(Sep-Oct):261.

While electrosurgical burns are common, the mechanisms of skin destruction discussed in the following sections are equally important. In our estimation, they are responsible for at least as many accidental injuries as electrosurgery.

DC Voltage

Even low DC voltages can result in skin damage (Leeming, 1970).

In one case reported to us, faulty DC circuitry in the warning circuit of an ESU resulted in burns from the application of 14 volts DC. Such burns are the result of electrolysis of skin moisture (physiologic saline), which produces sodium hydroxide at the negative electrode, resulting in localized full-thickness skin lesions. We approximate these conditions in our laboratory and documented the additional possibility of skin discoloration from prolonged contact with the terminals of a 9-volt battery.

We recommend that DC devices for patient care be given the same close scrutiny for electrical safety that AC devices have received. Additionally, we strongly recommend that unprotected battery terminals not be placed in prolonged contact with the skin. This could occur, for example, if the battery cover were missing from an ECG telemetry transmitter or from a transcutaneous electric nerve stimulator (TENS) worn by the patient.

Thermal

Direct Contact

Thermal burns constitute another major group of injuries during surgery. One common mechanism is prolonged contact with a moderate heat source, such as a hyperthermia blanket.

Although many factors determine whether skin destruction results from exposure to a hot surface, the most important factors are temperature and exposure time. The lowest direct-contact temperature responsible for a cutaneous burn in humans is 44° C (Moritz, 1947), with irreversible injury occurring after six hours of exposure. Below this threshold temperature, blood flow to the tissue tends to affect temperature distribution in the skin only slightly. However, once the threshold temperature has been reached, ischemia caused by pressure or surgical technique may well increase the rate at which injury occurs. Higher temperatures may cause injury within proportionately shorter times. Therefore, full-thickness injury may result from either brief exposure to intense heat or prolonged exposure to moderate temperatures.

Reports of incidents and our own investigations have revealed that most direct-contact thermal skin injuries occur during lengthy surgical procedures in which hyperthermia blankets are used and which involve extracorporeal circulation or cross-clamping of the aorta. In cases where excessive temperatures were known to be present, the thermal injury presented a linear pattern of burns (usually full thickness) that exactly matched the pattern of tubing in the hyperthermia blanket. Injuries tended to be concentrated in sites where pressure was greatest, such as over the sacrum. Such a pattern is consistent with one of moderate, but repeated, thermal injury combined with low-grade ischemia (from either the surgical techniques employed or pressure).

We are also aware of many incidents in which a linear pattern of injury appeared, corresponding to the hyperthermia blanket tubing, but the unit was not used in a heating mode and its temperature control circuitry was operating properly. In these cases, pressure (discussed later) was the probable cause of injury. The weight of the patient's body increased the pressure on tissue touching the water-filled ridges of the blanket.

We found in our first evaluation of hypo/hyperthermia machines (Health Devices, Vol. 1, p. 52) that most of the units built before 1971 lacked a backup thermostat to prevent heating past physiologically tolerable limits. Units of such design were implicated in multiple incidents of patient injury, resulting in publication of hazard reports (Health Devices, Vol. 1, p. 190; Vol. 3, p. 232). Even more recent units having backup thermostats are occasionally involved in patient injuries, but these tend to result from operator error combined with improper maintenance (Health Devices, Vol. 3, pp. 229, 231).

Routine inspection and preventive maintenance are essential to ensure safe operation of these devices (Health Devices, Vol. 3, p. 222), and user education and vigilance during use are critical. Other helpful measures include the interposition of fabric between the hyperthermia blanket and the patient and assurance that no creases or folds that might concentrate heat are present in the blanket.

The temperature of the heating fluid should be constantly monitored and never allowed to exceed 42° C. Judicious use and proper maintenance of modern hyperthermia devices should markedly decrease the incidence of patient injury.

Irradiant Heat

Irradiant devices may also cause thermal injury. We have investigated incidents in which high-intensity examination lamps used in conjunction with radiant warmers have caused second-degree burns on neonates. Malfunctioning or improperly maintained radiant warmers have also caused burns.

It should not, however, be unquestionably assumed that a radiant device used on a patient was responsible for a lesion. For example, Fleishman (1977) reported that a supine neonate's dorsal side was "burned" by a radiant warmer because a disposable diaper had been placed under the patient with the plastic against the skin. (This was done to catch the urine for volume measurement.) The physician theorized that the sides of the plastic layer exposed to radiant energy became hot and transmitted the heat to the plastic touching the skin. This theory is not plausible, however, since a thin plastic sheet is a very poor heat conductor and the areas of the plastic sheet in contact with the patient were shaded from irradiation. The physician apparently did not think it significant that the patient had been lying in a pool of urine (contained in the diaper) for several hours. In our opinion, the urine, and not the radiant warmer, was responsible for the "burn."

Other sources of irradiant energy that have resulted in burns include pediatric transilluminators (McArtor, 1979) and high-density operating room lamps when used without heat filters (Stoner, 1976). Similar incidents have been reported by hospital members of the Health Devices System.

Transcutaneous oxygen electrodes also have been associated with thermal injury (Hardman, 1980). These electrodes and transcutaneous carbon dioxide electrodes contain a heater that maintains electrode temperature at about 44° C, the threshold for contact thermal injury of human skin after six hours. Current clinical procedures call for repositioning the electrode every four hours. However, this criterion does not account for any inaccuracies of the thermostat, and it may be insufficient for some neonates and elderly patients with sensitive skin. On these patients, we suggest more frequent electrode relocation to prevent burns. Even with these precautions, burns beneath electrodes still occur, and reports from the field indicate that they are not uncommon. The medical staff must weigh the risk of thermal burns against the advantages of using the electrodes (as opposed to performing routine blood gas analysis).

Chemical

Prepping and Degreasing Agents

Chemicals may be toxic to the skin or may interact with other substances in exothermic reactions to cause skin destruction. Loss of the lipid protective covering of the skin resulting from preoperative bathing and the use of degreasing agents, such as Freon or ether, makes the skin particularly vulnerable to irritation.

Chemical injuries may appear quite similar to thermal burns and tend to occur where the agent pools or is in constant contact with the skin, especially if mild heat or pressure is applied. Characteristic locations of injuries from pooled prepping agents are areas in contact with a hyperthermia blanket and areas beneath a tourniquet.

Merthiolate (thimerosal) is a common cause of skin destruction. In addition to its irritative properties, Merthiolate in contact with an aluminum dispersive electrode produces aluminum oxide and heat, leading to thermochemical burn (Health Devices, Vol. 2, p. 271). Freon and isopropyl alcohol, in combination with gentle pressure and mild heat from a hyperthermia blanket, have resulted in injury (Klein, 1976).

Tincture of iodine may cause chemical injuries if allowed to remain on an infant's sensitive skin or if confined under an occlusive or acetone-containing spray dressing (Morgan-Hughes, 1978).

Sterilizing Agents

An agent which may result in an epidemic pattern of skin injury is ethylene oxide (EtO), a gas commonly used to sterilize heat-sensitive OR materials. An outbreak of skin damage resulted from incompletely aerated patient gowns sterilized with EtO (Biro, 1974). Such injury resembles "scalded skin syndrome" and occurs in pressure areas. Using an incompletely aerated EtO-sterilized device, such as an anesthesia mask or hyperthermia blanket, on the patient may result in skin injury, especially if the skin is moist (Health Devices, Vol. 5, p.130).

Preventing chemical injury to the skin requires care on the part of the surgeon and the operating room staff. All prepping agents should be applied with great care and should not be allowed to pool beneath the patient or beneath a tourniquet. Special care should be taken to avoid contact between Merthiolate (thimerosal) solution and aluminum dispersive electrodes. OR supervisory personnel should ensure that proper aeration procedures are followed for all materials sterilized with EtO. Such precautions should eliminate all but the occasional idiosyncratic reaction.

Mechanical

Pressure

An often unrecognized source of skin destruction in the OR is prolonged immobility and pressure, which can lead to pressure necrosis. These injuries may resemble those caused by an ESU or hyperthermia unit; in fact, many lesions were originally suspected of having been caused by these devices. Most such injuries result from prolonged immobility, in which tissue pressure exceeds the critical closing pressure of subcutaneous blood vessels, so tissue ischemia exceeds physiologic tolerance.

Hicks (1971) reported a 13% incidence of pressure sores following surgery. Such injuries tend to be more common in the elderly, probably because of increased tissue fragility, poor overall physical condition, and low perfusion, but Hicks also noted that 69% of skin ulcers occurred in patients under age 60, with 30% under 19 years of age. A common factor in all cases was prolonged operative time. Gendron (1980) concluded that operative times of two hours or less were not likely to result in pressure necrosis, while procedures lasting longer than three hours predisposed the patient to skin injury from pressure.

Alopecia (loss of hair) caused by prolonged immobilization of the head has also been documented following cardiovascular (Lawson, 1976; Elder, 1977) and gynecological (Poma, 1979) procedures. These injuries occur early in the postoperative period as edema and a very painful seroma of the occipital scalp, followed by ulceration and transient or permanent localized hair loss.

Even moderate pressures applied for as little as one hour have caused ischemic injury in experimental animals (Kosiak, 1961). Such pressures are routinely exceeded over bony prominences in the supine human. Obesity offers no real protection; while the pressure may be somewhat lessened by fat, wider areas are at risk (Foster, 1979).

Conventional operating table pads are not capable of adequately protecting against pressure sores (Souther, 1971). However, Gendron's study during a one-year trial has shown that the use of a full-length silicone gel pad proved effective in preventing serious pressure injuries in surgical procedures lasting longer than three hours. Gendron considered other static or dynamic pressure relief devices to be unacceptable for surgical application due to concerns over electrical safety, positional stability, and/or asepsis. These devices included water-filled pads, convoluted foam pads, sheepskins, air mattresses, vacuum splints, and alternating pressure pads. We agree that these devices are not well suited for use during surgery.

One disadvantage of the silicone gel pad is that warming or cooling the patient may prove difficult since the hyperthermia blanket must be placed under the gel pad (placing the gel pad under the hyperthermia blanket will not provide the desired cushioning). Prewarming or precooling the gel pad before placing the patient on it may alleviate this problem, but long "lag" times on further intraoperative demands for warming or cooling should be expected.

Straps used to secure the patient during surgery are another source of pressure. Once tightened, they may cause excessive pressure on the skin directly beneath them and/or add to forces exerted elsewhere on the patient. The inadvertent placement of a strap over an ESU dispersive electrode or an ECG electrode is particularly hazardous. In such cases, the strap may press the electrode's electrical connector (usually a small metal disc) against the skin with considerable force, resulting in a pressure sore. This is more serious with an ESU dispersive electrode because the force may distort the electrode's shape and prevent adequate dispersion of current. Nonuniform current dispersion can create "hot spots" beneath the electrode that may result in burns from high current densities.

Plastic adhesive drapes should be removed carefully from patients with particularly fragile skin to prevent tearing of the skin (Frazier, 1971).

Shearing Forces

Shearing forces also contribute to pressure sores. If the position of the operating table is changed while the patient is anesthetized, the weight of the torso tends to move the body in the direction indicated, while the skin may be fixed by friction. Skin destruction is particularly likely in the sacral area, where the blood supply to the posterior tissues exits the well-anchored deep fascia into the looser subcutaneous fascia. Angulation occurs, and thrombosis of the affected vessels with ischemic ulceration may result. (Reichel, 1978).

While the silicone gel pads may adequately distribute pressure while meeting other qualifications for surgical use, ancillary measures will continue to be necessary. Special care should be taken in those cases in which a hypotensive or ischemic period might be expected. Alterations of the operating table should be kept to a minimum. If repositioning the patient is necessary after induction of anesthesia, it should be performed with care, and the patient should be lifted into position, rather than rolled or tugged, to avoid shearing forces. Reducing the operating time, if possible, would be helpful. The head position of supine patients should be changed by the anesthesiologist every 30 minutes to avoid occipital alopecia.

Summary

Accidental skin destruction continues to occur with regrettable frequency. When an incident occurs, it may be very difficult to identify the contributing factors. Avoid the tendency to assume that a particular device, such as an ESU or hyperthermia blanket, was at fault. Consider very carefully the possibility of multiple causes, any one of which would not have caused the lesions.

Conduct a thorough etiological investigation as soon as possible. Document the clinical circumstances in which the injury occurred, and take color photographs of the lesion as soon as it is discovered and periodically as it heals. The circumstances of the incident and any characteristic patterns of skin destruction may help identify the causative mechanisms.

Very complex investigations and those which may involve legal action or simple defensiveness on the part of staff members may require the assistance of objective, competent outside investigators. Whether for legal reasons or not, an investigation should be conducted with the objective of preventing similar occurrences.

The summary below "Help Prevent Skin Injury" lists ways to prevent skin injury to patients. The table summarizes the mechanisms of inadvertent skin destruction and provides general guidelines for incident investigation and prevention. It is limited to the OR but is not intended to be inclusive.

Help Prevent Skin Injury

Skin injuries on surgical patients may occur by one or more of the mechanisms listed below.

Electical

Before the procedure:

  • Examine electrosurgical equipment and accessories for damaged insulation, cables, or connectors and cracked, dirty, or bent return plates*
  • Place return electrode* close to the surgical site and ensure good patient contact
  • Keep ECG electrodes and patient temperature probes far from the surgical site and the return electrode*
  • Keep electrosurgical cables clipped away from the patient and from monitoring cables
  • Prevent battery terminals (e.g., on an ECG telemetry transmitter) from contacting patient's skin; ensure battery cover is in place

  During the procedure:

  • Activate the electrosurgical unit only when touching blade to tissue
  • Avoid unnecessary or prolonged activation
  • Do not continue to increase power settings if you are not getting desired results look for other problems
  • Check contact with return electrode* after repositioning patient
  • Protect unused active electrodes

Thermal

Hypo/hyperthermia unit operation and use:

  • Maximum backup thermostat setting should be 42° C
  • Ensure proper placement of patient temperature probe (also check after repositioning patient)
  • Watch both circulating water temperature* and patient temperature
  • Place a sheet between hypo/hyperthermia blanket and patient**

PO2 and PCO2 electrode operation and use:

  • Maximum operating temperature should not exceed 44° C
  • Move electrode to new site at least every three hours

Radiant warmer and lamp operation:

  • Use automatic mode for safer warming
  • Secure temperature probe to a skin surface that faces the heater, never beneath the patient or in the rectum
  • Do not estimate the heat reaching the patient with your hand—this method is not reliable
  • Heat from OR and examining lamps is cumulative; be cautious when using several lights simultaneously
  • "Cold" fiberoptic light sources can burn do not leave light source on when endoscope is not being used for viewing
  • Do not allow mercury-containing compounds such as Merthiolate (thimerosal) to contact aluminum electrodes the resultant thermochemical heating may injure the patient

Chemical

  • Do not allow degreasing agents or prepping solutions to pool beneath patient or to contact electrodes
  • Aerate all EtO-sterilized materials completely before use

Mechanical

  • Check OR table mattress for sufficient thickness
  • Consider placing a thin silicone gel pad between patient and hypo/hyperthermia blanket for long procedures
  • Avoid leaning heavily on patient for prolonged periods
  • Ensure that skin is not being stretched or pulled after adjusting patient or table position
  • Change patient's head position every 30 minutes to prevent alopecia
  • Be sure that circulation is not restricted by the patient's position or restraining straps

*   Also called dispersive electrode, ground plate, patient plate, butt plate, grounding plate.

** For lengthy procedures, also consider placing a thin silicone gel pad on top of the hypo/hyperthermia blanket to reduce pressure.

OR Skin Injuries: Common Sources and Prevention

Mechanism of Injury

Device or Agent

Examples

Prevention

Personnel*

ELECTRICAL

Electrosurgery

Electrosurgical unit

Lesion beneath dispersive electrode

Gel and position dispersive electrode properly.

Circulating Nurse

Lesion at ECG electrode

Avoid placement of ECG electrodes in current path between ESU active and dispersive electrodes. Keep ESU cables away from ECG leads.

Circulating Nurse
Anesthesiologist
Nurse Anesthetist

Lesion occurs after repeated requests by surgeon to increase power If unit not performing normally, check continuity of all leads, connectors, and dispersive electrodes.

Surgeon**
Instrument
Nurse**
Circulating Nurse**
Scrub Nurse**

Low voltage DC

ECG telemetry transmitter

Lesion from prolonged contact with exposed battery terminals

Cover battery terminals

Anesthesiologist
Nurse Anesthetist
Nurse
Therapist

THERMAL

Hypo/hyperthermia unit

Lesions on buttocks, back, thighs, back of knee, calves and heels; hypo/hyperthermia unit turned on

Limit blanket temperature to minimum required to warm patient. Maximum temperature of backup thermostat should be £ 42+C.

Clinical Engineer
Anesthesiologist**
Nurse Anesthetist**

PO2

Lesion beneath electrode

Move electrode to new site every 3 hours. Maximum operating temperature should not exceed 44+C.

Perfusionist**
Anesthesiologist**
Nurse Anesthetist**
Clinical Engineer

CHEMICAL

Prepping and degreasing agents

Acetone, ether, Freon, alcohol, providing-iodine, tincture of iodine. Hibitane (chlorhexidine digluconate), Merthiolate (thimerosal)

Lesion on buttocks, edge of back, dorsal thigh and knee

Do not allow prepping agents to pool beneath patient.

Surgeon
Scrub Nurse

Aluminum ESU dispersive electrode

Lesion at electrode site when Merthiolate (thimerosal) contacted electrode, causing exothermic reaction

Do not allow Merthiolate or other mercury-containing compounds to contact aluminum electrodes.

Surgeon
Instrument Nurse
Circulating Nurse
Scrub Nurse

Sterilizing agents

Ethylene oxide (EtO)

Lesions around mouth following line of anesthesia mask contact

Aerate ALL EtO sterilized goods properly before use.

CSR Supervisor
Anesthesiologist
Nurse Anesthetist

MECHANICAL

Pressure and shearing forces

Hypo/hyperthermia unit

Lesions on back and buttocks that follow lines of blanket, but unit not used for heating during procedure

Consider using a thin silicone gel pad over blanket for long procedures.

Circulating Nurse
Scrub Nurse
Surgeon

OR table

Lesions on buttocks, back of heels; OR table position adjusted after patient was anesthetized

Consider using a thin silicone gel pad over blanket for long procedures. Be sure that skin is not being pulled or stretched after adjusting table or patient position.

Surgeon

Scrub Nurse

OR table

Bald spot forms on head several days after procedure

Change head position every 30 minutes.

Surgeon
Scrub Nurse

OR table

Lesion on arm; patient's arm was tucked under sheet at side during procedure; ESU not used

Avoid leaning heavily on patient for prolonged periods. Surgeon
Instrument Nurse
Scrub Nurse

Positioning straps

Lesion on leg near area under positioning strap

Be sure that positioning straps are not restricting circulation.

Scrub Nurse
Anesthesiologist
Surgeon

*  These personnel are the most capable of preventing skin injury under the given circumstances.  The clinical engineer is responsible for periodic inspection and preventive maintenance of the equipment.

** Operator vigilance is important throughout the procedure.

UMDNS Terms

  • Electrodes, Electrosurgical [15-579]
  • Electrosurgical Units [11-490]
  • Germicides [18-159]
  • Hypo/Hyperthermia Blankets [12-067]
  • Hypo/Hyperthermia Units [12-068]
  • Lights, Examination [12-276]
  • Oxygen Monitors, Transcutaneous [12-592]
  • Pressure Pads [12-936]
  • Restraints [13-346]
  • Transilluminators [14-130]
  • Warmers, Radiant [13-248]   

Cause of Device-Related Incident

Device factors:  Design error/labeling error; Device failure; Device interaction; Improper maintenance, testing, repair, or lack or failure of incoming inspection; Manufacturing error

User errors:  Failure to read label; Inappropriate reliance on automated feature; Incorrect clinical use; Incorrect control settings

Support system failure: Use of inappropriate devices

Mechanism of Injury or Death

Burn (electrical, thermal, chemical)


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