LEFT OR RIGHT , UP OR DOWN : A CASE FOR POSITIONING OF UNCONCIOUS HEAD-INJURED PATIENTS

Nursing care activities have been proved to cause increases in intracranial pressure (ICP) which could be detrimental to the patient’s health. Because positioning is one of the activities that causes the greatest pressure changes it was evaluated in this study. Cumulative increases also occur when nursing care activities are carried out in quick succession. The analysis o f the data and literature suggest that the backrest position with the head o f the bed evle\>ated 30 to 45 degrees is the best position for a patient with increased ICP. I f further research should prove that this position has a negative influence on the cerebral perfusion pressure, these recommendations will have to be revised

Nursing care activities have been proved to cause increases in intracranial pressure (ICP) which could be detrimental to the patient's health.Because positioning is one of the activities that causes the greatest pressure changes it was evaluated in this study.Cumulative increases also occur when nursing care activities are carried out in quick succession.The analysis o f the data and literature suggest that the backrest position with the head o f the bed evle\>ated 30 to 45 degrees is the best position for a patient with increased ICP.I f further research should prove that this position has a negative influence on the cerebral perfusion pressure, these recommendations will have to be revised Opsomming Daar bestaan bewyse dat verpleegsorghandelinge 'n toename in intrakraniale druk (IKD) tot gevolg kan hê wat 'n nadelige effek op die pasiënt se gesondheid uitoefen.Aangesienposisionering een van die aktiwiteite is wat die grootste drukveranderinge tot gevolg het, was dit in die ondersoek geëleveer, Kumulatiewe drukstygings ontstaan wanneer verpleegsorghandelinge vinnig op mekaar volg.By die ontleding van die data sowel as die literatuur blyk dit dat die rugliggende posisie met die koppenent van die bed tussen 30 tot 45 grade geëvalueer die beste posisie vir die pasiënt met verhoogde IKD is.Indien dit sou blyk dal die serebrale perfusie druk negatiefbeinvloed word deur hierdie pesisie moet hierdie aanbevelings egter hersien word

IN TR O D U C TIO N
Nursing care activities have been proved to cause increases in intracranial pressure (ICP) which could be detrimental to the patient's health.During the past decade studies have appeared in the lite ra tu re su g g e stin g the negative or positive effects o f various positions or nursing actions.In most textbooks on the nursing care o f head injured patients it is suggested that the head of the bed be elevated between 30 to 45 degrees unless symptoms of shock are present (Sherry, 1982:31;Marshall & B ow ers, 1982:314; D av en p o rt-F o rtu n e & D unnum , 1985:368; V iq u e s n e y ,1987:47).However, none o f these authors take cerebral perfusion pressure into account.Could it be possible that although the ICP is being treated by the 'head up' position the effects on cerebral perfusion pressure (CPP) could in itself cause harm to the patient?Is it possible to give the correct nursing care to patients w ho have suffered severe head injuries without proper m onitoring o f the relevant haem odynam ic parameters?As we arc all aware, nothing can be done to reverse the primary brain injury, but it is important that everyone should try to limit secondary brain injury which is often worse than the primary injury.Due to fear o f aggravating the injury nurses tend to keep 'hands o f f so that no harm can be done.This does not mean it is the best option.Meticulous nursing care still forms the basis for quality nursing care which is essential for the patient's wellbeing.
One of t he mai n factors associ ated wi th changes in ICP is the positioning of the patient.Patients need to be positioned in the best possible way without causing too much o f an increase in ICP.The purpose of this study was to establish the best position for nursing o f head-injured patients, as well as the best way to schedule repositioning in order to cause the least increase in pressure.
ICP will be described briefly to clarify the rest o f the article.

IN T R A C R A N IA L P R E SSU R E (ICP)
In 1977 the Richmond group examined 225 seriously brain injured patients and monitored their ICP.They found that 70% of the patients w ith b rain le sio n s re q u irin g su rg ery had increased ICP and that 30% o f the group died as a result o f the increased pressure.In patients with diffuse brain injury 33% had increased p r e s s u r e , o f w h o m f o u r p e r c e n t w e re u n co n tro lled .In the case o f intracerebral contusions 70% o f the patients had increased p r e s s u r e , s ix p e r c e n t o f w h o m w e re uncontrolled.O f the patients who underwent surgery 50% continued to have problems with increased ICP (Ward 1986:398).Bruce et al (1981:170-178) reported a 59% incidence of increased ICP in children with serious head injuries.
It appears that patients with increased ICP have a poorer prognosis.W hether this can be ascribed to the increased pressure per se or to the magnitude o f the primary injury is difficult to determ ine (Jennett and Teasdale 1981:127;Ward 1986:398).
H owever, it is im portant to stress that the ultimate consequenoes o f a head injury are a combination o f the primary injury at the time of the impact and the secondary injury caused by th e in c r e a s e d IC P a n d v a r io u s o th e r complications.This is why it is important to avoi d or I i mi t secondary i njury as far as possible at all costs.

P H Y SIO L O G Y O F IN T R A C R A N IA L P R E SSU R E
Normal ICP usually varies between 0 and 10 m m llg (80-180 mm H2O).A pressure of more than 15 m m llg is regarded as abnormal.The pressure oscillates during the respiratory and cardiac cycle, but these oscillations have no clinical significance (Hickey 1981:143;Nikas 1982:30).
T he b rain is a c c o m m o d a te d in a closed container with inflexible walls.The skull is filled a lm o st to c a p a c ity w ith the brain parenchym a w hich occupies approxim ately 86% o f the total volume, while the CSF takes up about 9-10% and the total intracranial blood volume approximately 5-7% (Jennett 1970:4).The ICP depends on a delicate balance between the brain tissue, C SF and intracranial blood volume.An increase in volume o f any of the three components must be at the expense of the others, otherw ise the ICP rises.There are, however, compensatory mechanisms which can accommodate slight changes.
The theoretical volum e-pressure curve gives an indication of the compliance or compensation that may be allowed.(See Figure 1).An initial increase in intracranial volume (1CV) does not cause a rise in ICP.A slight pressure increase docs, however, begin to occur at a certain level o f unit volum e increase (a).A considerable pressure increase occurs later, even if the unit of volume increase remains constant (b).The flat p art o f th e p re s s u re c u rv e r e f le c ts the compliance o f the brain where volum es can com pensate and the pressure can be kept constant.The sharp rise in pressure reflects the decompensation phase in which slight increases in volume cause dram atic pressure increases (Nikas 1982:30).
The brain demands a constant blood flow to function effectiv ely .C ereb ral blood flow usually remains relatively constant and depends on cerebral perfusion pressure (CPP).CPP is the difference between the mean arterial pressure (M AP) and ICP (CPP = MAP -ICP) and varies between 80 and 100 m m llg (N ikas 1982:54) The interaction between CPP and ICP is very complex.A rise in ICP can, for instance, cause a drop in CPP, while a primary increase in CPP as a result o f vasodilatation, can cause a rise in ICP.A critical point is reached when the ICP is within 40 m m llg of MAP because cerebral blood flow dim inishes as the CPP declines (Jennett 1981:55).
An analysis o f findings reported in the literature will be given to determine the influence of positioning on ICP.

M E T A -A N A L Y SIS O F T IIE L IT E R A T U R E
M itchell (198 0 :1 5 0 ) found that very little systematic research had been done on ICP and the factors that influence it.Although there are a num ber o f anecdotal reports on specific incidents, qualitative and quantitative pressure increases and stimuli frequencies are seldom found in the literature.A number of researchers have published anecdotal reports on aspects that influence ICP si nee Lundberg( 1960:193) found that physical activities and emotional outbursts lead to plateau increases.The relationship between head rotation and positioning and ICP has often been studied but never quantified.
One o f the first systematic research reports on nursing care activities and ICP appeared in 1977.Shalit and Umansky reported on pressure changes that occur during positioning.In this case, too, the duration and quality o f the increases were not investigated (Shalit and Umansky, 1977:881-886).
In 1978 M itchell and M auss (1978:4-10) studied factors that influence ICP.They used CSF drainage through a ventricle catheter as an index o f ICP and, therefore could not also measure the quality of the increases.They found that activities such as repositioning were almost alw ays associated with CSF drainage, while passive movement almost never led to CSF drai nage uni ess i t occurred si mul taneousl y wi th the former activities (M itchell, 1980:150).Mitchell et al. (1980:565-568) conducted a further study in 1980 about aspects such as passive movement, turning and head rotation and ICP.They found that the pressure rose after a change of position in 88 percent o f cases and that the duration o f the increase w as 5 minutes.A further finding was that activities performed at 15 minute intervals resulted in a cumulative pressure i ncrease, but that that this did not occur if an hour elapsed between repositionings.Head rotation also led to pressure increases (Mitchell, 1980:150,151).
W eed d em o n strated as early as 1929 that ventricular fluid pressure in dogs dropped with elevation o f the head and rose when the head w as lowered.Nornes and Magnaes found in 1971 that neck flexion, hip flexion, the supine p o s itio n a n d 9 0 d e g r e e s h ead ro ta tio n consistently resulted in increased ICP.This corresponds with studies by Hulmc and Cooper (1977) and Shalit and Umansky (1977).Lipe and Mitchell (1980) believe that an elevated ICP ^ is c a u se d by a d ro p in v e n o u s o u tflo w , V alsalva's manoeuvre and obstruction o f CSF outflow from the basal cisterns (G oldberg etal., 1983:428-439;Mitchell, 1980:151;Mitchell, Ozuna and Lipe, 1981:213).
Parsons and Wilson studied changes of position.In 200 observations they found that all position changes, with the exception o f elevation of the head, were accompanied by an increase in heart rate, mean arterial blood pressure, mean ICP and cerebral perfusion pressure (1984:68-75).These fin din g s co n cu r w ith those o f a study by Boortz-Marx (1985:89-94).
Maximum increases in ICP were observed by Hulme and C ooper (1976:259) during neck flexion, bilateral jugular vein obstruction and head rotation to the right if the baseline pressure w as above 10 mm l Ig.This may i ndicatc that this group of patients had high brain elastance and that they were, therefore, more susceptible to v e n o u s o u tflo w o b stru c tio n and volum e increase.Lipe andMitchell (1980:1036) found that the left lateral position resulted in greater pressure increases than the right lateral position.This tendency is ascribed to anatomical differences.T h e le ft in te rn a l ju g u l a r v e in is o fte n anatomically sm aller than its right counterpart, thus increasing its risk for potential obstruction.Furthermore, the left internal jugular vein joins the left subclavian vein al right angles to form the b ra c h io c e p h a lic v ein , w hile the right   (1981:184-194).Mitchell, on the other hand, found a significant difference if patients rested for at least an hour because the pressure had su ffic ie n t tim e to re tu rn to the b a se lin e (1980:217).Although it is often difficult to allow patients in critical care units to rest for an hour, these findings stress the fact that careful nursing care planning can contribute to better control of ICP (M itchell, 1980:153).
Shalit and Umansky (1977:886) even go as far as to claim "that the cum ulative effect o f increases in intracranial pressure which take place during routine m anagem ent o f these patients may be a major factor in determining the outcom e o f the illness".It seem s that neither repositioning nor possibly either o f the lateral positions have a significant influence on any o f the other haemodynamic parameters, but these should nevertheless be carefully applied to patients with elevated ICP (see Table 1).March et al. (1990:375-381) found that cerebral perfusion pressure is lowered in som e patients by elevating the head o f the bed, even though it has a positive effect on the ICP.A lthough the fin d in g s did not o ccu r co n sisten tly in all patients, it may be a factor which demands further research.

METHOD AND DESIGN
A d e s c r ip tiv e , n o n -p a rtic ip a n t,e m p iric a l o b se rv a tio n a l stu d y w as u n d ertak en in a neuro-surgical intensive care unit (N-ICU) to establish the effect o f positioning on the ICP of severely head-injured patients.A head injured patient with a com a scale count of eight or less, loss o f consciousness o f longer than six hours and/or an abnormal com puter tomographic scan is regarded as seriously head-injured (Jennet et al. 1977:292).In the selected research unit measuring the ICP by means o f an epidural pressure m onitor or a ventricular catheter was standard protocol.
Patients whose ICP w as monitored for less than a 12 hour period were omitted from the study.However, the initial twelve hours were part of the 72 hour study monitoring period.The v a ria b le s s tu d ie d w e re p o s itio n in g and repositioning o f the patient in the left lateral, right lateral, supine, and head o f bed elevated 0, 15,30 or 45 degrees and their effect on the ICP.The various factors that influence ICP will be discussed in further articles.However, all the p atien ts w ere intubated and m echanically ventilated as part of the treatment protocol for elevated ICP.
As a non-participant observer the researcher did all the observations and m onitoring o f the patien ts over a 72 hour period follow ing admission to the N-ICU.

D A T A -A N A L Y SIS
The patients' positions were changcd every two to four hours.Conventional hospital beds, the heads of which can be turned up were used in the research unit.W henever possible patients were turned by at least tw o nurses standing on either side o f the bed.The log rolling method was followed throughout to turn the patients onto alternate sides.The various treatment regimes and other variables were taken into account.E ach p a tie n t's m ean IC P, mean pressure increase (m axim um ICP minus mean ICP) and the duration o f the pressure increase was measured during the 72-hour period.Three hundred and sixty-nine events o f positional changes were observed.The mean base-line ICP was 13,48 m m llg, the mean pressure increase 15,70 m m llg and the duration of increase 6,34 m inutes.T h is m eans that the mean peak pressure obtained w as 29,18 mmHg.(Peak pressure refers to the highest ICP occurring d u r in g a n u r s in g in t e r v e n t io n a n d is synonymous with maximum pressure, but is used to prevent confusion between maximum pressure and maximum pressure increase.)The maximum pressure increase observed was 39,18 mmHg which m eans the peak pressure could have been as high as 52,66 m m llg.These are d a n g e r o u s in c r e a s e s in th e a lr e a d y compromised patient and should be avoided.(See Table 2.) The data were subjected to the Fisher-exact-tcst in order to determine the relationship between the mean pressure and the duration o f the pressure increase.A distinction w as made between pressures of more and less than 15 mmHg, and between a duration of increase of more and less than 10 minutes.Possibly due to the sam ple size, no statistically significant difference could be demonstrated.This test was done to d eterm in e w h eth er p a tien ts w ith increased ICP ( mmHg) arc more apt to plateau increases (10 min).The findings from the available data seem to suggest that patients with increased ICP are more apt to plateau increases while those with pressures within normal limits are more li kely to have peak increases (see Table

3)
Repositioning is usually done during or after a bedbath or back care.This could cause a cumulative increase and duration o f increase, which could have a detrimental effect on the p a t i e n t 's IC P , as re p o r te d by M itc h e ll (1980:150).
Most of the patients were positioned with the head of the bed elevated 45 degrees.Patients were repositioned every two to four hours by changing their positions to backrest, left or right lateral.The data were analysed to ascertain w hich position caused the smallest baseline pressure difference.In the analysis the mean baseline pressure difference for each patient for e a c h p o s itio n a l c h a n g e w as c a lc u la te d .T h e r e a f te r th e m ean b a s e lin e p re s s u re d ifferen ce for each positional change was calculated.These results arc summarized in Table 4 and displayed in Figure 2 (a,b,c).
It would seem as though the greatest pressure differences were obtained when the patients were turned to the left lateral position (X = 2,38; max = 16,00).These results correlate with those o f Lipc & Mitchell (1980:1036).
The Fisher-exact-test w as performed on the data to determine whether there was a correlation between the frequency of nursing care activities and the duration of increase.In this ease a comparison w as made between two or more nursing care activities during one hour or less and a duration o f increase for more or less than 10 m in u te s .A s t a t i s t i c a l l y s ig n if ic a n t correlation w as established where more than two nursing care activities occurred within one hour and a duration of increase longer than 10 minutes (p = 0,018).
S p e a rm a n -c o rr e la tio n s w e re c a lc u la te d between duration o f increase and ICP-increase in one ho u r.In m ost ca se s a stasitically  When the mean for ICP-increase, duration of increase and frequency o f activ ities w ere calculated, a significant correlation between duration and frequency could be established (p = 0,04), but it could not be established for mean ICP-increase and duration o f increase (p = 0,55).A larger sample might have produced different results.
A sta tistic a lly sig n ific a n t d ifferen c e w as established with the M ann-W hitney-test where two or fewer activities occurred in one hour and those in which more than two occurred when compared to theduration o f increase (p = 0,007).
Careful planning o f nursing care activities is therefore, o f the utmost importance to ensure quality nursing care with the least negative influence on the ICP o f head injured patients.

C O N C L U SIO N S
T he repositioning o f severely head-injured patients should be planned carefully in order to lim it p ressu re in creases to the m inim um .In d iv id u a l p a tie n ts ' p re ssu re s sh o u ld be analyzed to establish sensitivity with regard to brain elastance.Positions that are not well tolerated by a particular patient should be avoided or if unavoidable allowed for only a very brief period.
In sum m ary, the data show: N ursing interventions that have a negative influence on the ICP should not be performed together or successiv ely .S ince a bedbath, repositioning, bronchial toilet and mouth toilet often cause significant ICP elevation, these procedures should be carefully scheduled and should not all be performed in quick succession as this will have a cumulative effect on the ICP.
It is important to record the particular positions or nursing actions to which the patient is most sensitive, in order that all the members of the The most important aspect, and this cannot be sufficiently stressed, is that the scheduling of patient care is determined by the patient and not by the nurse.
. CPP should not drop below 50 m m llg since functional changes set in when it drops below 40-50 m m llg (Nikas 1982:33).A CPP o f 30 mmHg is incompatible with life and leads to n e u ra l h y p o x ia an d c e ll d e a th (H ic k e y 1981:144).

R
e s e a rc h e r s c o u ld fin d n o s ta tis tic a lly significant effect on oxygen saturation and heart rate w hen th ey stu d ie d th e in flu e n c e o f repositioning and lateral and supine positions with the head of the bed elevated at an angle of 20 o r 4 0 d e g r e e s (N o ll an d F o u n ta in , 1990:243-251; Shively, 1988:51-59; Clark, Winslow, Tyler and White, 1990:557-561).Winslow et al. reported transient increases in heart rate and a decrease in mixed venous oxygen saturation which gradually returned to b aselin e lev els d u rin g the fo llo w in g four minutes.They state that should turning trigger large or prolonged changes in mixed venous o x y g e n sa tu ra tio n o r h e a rt ra te , p ro m p t repositioning and evaluation are needed to prevent adverse effects.
FIGURE 2 (C )Base-line Pressure Differences associated with Positional Changes

Table 1 Influence of specific body positions on ICP: Meta-analyses of literature.
The findings o f Lipe and Mitchell correspond with those of Hulme and Cooper, that is, that rotation to the right, especially at an angle o f 90 degrees, causes greater pressure increases, particularly if the baseline pressure is above 10 mmHg.

line Pressure Difference associated with Repositioning significant
correlation was established (p 0,05).
o b ta in e d from the research and literature show s that the ICP o f patients with severe head injuries should be monitored in order to evaluate and apply specific treatment modalities.Monitoring the ICP is important to nurses as it provides valuable information for optimum nursing care planning.The scheduling o f nursing interventions forms the basis o f planning.If the patient has high brain elastance and is inclined to frequent peak and plateau increases, unnecessary nursing actions should be scheduled at longer intervals.