Literature Week 2 HSOM
Dexter, F. (2003) Operating room utilization: information management
systems.
Definitions:
- Regularly scheduled hours: hours that an OR team member plans on working when
not on call.
- Surgical service: group of surgeons who share allocated OR time. Surgical service can
also be represented by a surgeon, group, specialty or department.
- Allocated OR time: interval of OR time with specified start and end on a specified day
that is assigned by the facility to a surgical service for scheduling cases.
- Case duration: the time from when a patient enters a OR until they leave the OR.
- Turnover time: the time form when one patients exits an OR until the next patient on
that day’s schedule enters the same OR. It includes clean-up times and setup times,
but not delays between cases.
- Under-utilized OR time: the difference between allocated OR time and the total
hours of elective cases including turnover times performed during the allocated OR
time. This is the time which the OR is not being used.
- Over-utilized hours: the hours that ORs run longer than the regularly scheduled
hours.
- Inefficiency of use of OR time: the sum of 2 products: (hours of under-utilized OR
time x the cost per hour of under-utilized OR time) plus (hours of over-utilized OR
time x the cost per hour of over-utilized OR time).
- OR efficiency: value that is maximized when the inefficiency of use of OR time has
been minimized. It differs from adjusted utilization in considering not just under-
utilized OR time, but over-utilized time too.
OR time is allocated based on OR efficiency using a service’s total hours of elective cases,
each workday, including turnover times. If a service has much over-utilized operating room
time, allocate more OR time so that the service will be within regularly scheduled hours.
Strategic planning decides how much of each resource there will be available.
Almost all surgeons have a positive hospital contribution margin for their cases. If a case can
be performed safely, than it makes no economic sense to not perform the case. Allocating
Or time based on OR efficiency is rational.
Many hospitals have ICUs that often fill, causing delays or cancellations of surgical cases.
Other than staffing/building more beds, two strategies to deal with this:
- Adjust the days that services are scheduled to perform surgery to reduce the risk of
delays/cancellation.
- Provide surgeons with flexibility in the days when they have OR time, so that cases
can get onto the OR schedule to assure that the bottleneck (the ICU) is always full.
The bottleneck to carrying out surgery is ICU beds, then when there is ICU capacity
the case is done.
Day of the week is the best predictor of a service’s workload. OR allocations for each service
should vary by day of the week. One should calculate how many ORs should be staffed daily
for each service, and for each how many regularly scheduled hours of staffing is needed. To
1
, calculate: start with 0h and increase staffed hours until additional increases in staffed hours
causes the efficiency of use of OR time to decrease for that service. Increasing the staffed
hours causes the efficiency of use of OR time to increase progressively to a maximum, after
which it decreases. Allocating less hours then needed to complete the service safely leads to
over-utilized hours, and allocating more hours than needed is under-utilized hours.
The author recommends that each quarter, OR allocations be readjusted using data from
the preceding 7-11 months. Data can be obtained from OR info systems, EPD, billing data.
OR managers can schedule cases based on maximizing OR efficiency while leaving case
scheduling decisions to the convenience of surgeons/patients, by following three scheduling
rules:
- A service (surgeon) should not schedule a case into another service’s OR time if the
case can be completed within its own regularly scheduled OR time. OR allocations
are calculated based on expected workload on the day of surgery. Each service fill
their time at different rates.
- If a service (surgeon) has already filled its regularly scheduled OR time, then to
maximize OR efficiency, its new case should be scheduled into another services’
regularly scheduled OR time instead of in over-utilized OR time.
- A case should not be scheduled into over-utilized OR time if it can start earlier in
another service’s ORs.
de Bruin et al. (2009) Dimensioning hospital wards using the Erlang loss
model.
Most hospitals organize their beds into unit that are used by one or more clinical disciplines.
Nowadays it is also being organized based on length of stay (short/med/long), level of care
(intensive/med/normal) or urgency (elective, urgent, emergency). Distribution of beds is
based for big part on historically obtained rights. Capacity planning issues driven by
available budgets and target occupancy levels instead of service level standards (e.g. %
refused admissions, waiting times etc).
Also some data-issues: in Dutch hospitals registration is based on number of admissions, day
treatments, nursing days and no. of out-patient visits. Budget based on these parameters
via contracts with insurers.
A structural model of the patient flow through a clinical ward:
- Arrivals: patients arrive to the system and get admitted if there is a bed free. If not
then they are refused. There are scheduled and unscheduled arrivals.
2
Dexter, F. (2003) Operating room utilization: information management
systems.
Definitions:
- Regularly scheduled hours: hours that an OR team member plans on working when
not on call.
- Surgical service: group of surgeons who share allocated OR time. Surgical service can
also be represented by a surgeon, group, specialty or department.
- Allocated OR time: interval of OR time with specified start and end on a specified day
that is assigned by the facility to a surgical service for scheduling cases.
- Case duration: the time from when a patient enters a OR until they leave the OR.
- Turnover time: the time form when one patients exits an OR until the next patient on
that day’s schedule enters the same OR. It includes clean-up times and setup times,
but not delays between cases.
- Under-utilized OR time: the difference between allocated OR time and the total
hours of elective cases including turnover times performed during the allocated OR
time. This is the time which the OR is not being used.
- Over-utilized hours: the hours that ORs run longer than the regularly scheduled
hours.
- Inefficiency of use of OR time: the sum of 2 products: (hours of under-utilized OR
time x the cost per hour of under-utilized OR time) plus (hours of over-utilized OR
time x the cost per hour of over-utilized OR time).
- OR efficiency: value that is maximized when the inefficiency of use of OR time has
been minimized. It differs from adjusted utilization in considering not just under-
utilized OR time, but over-utilized time too.
OR time is allocated based on OR efficiency using a service’s total hours of elective cases,
each workday, including turnover times. If a service has much over-utilized operating room
time, allocate more OR time so that the service will be within regularly scheduled hours.
Strategic planning decides how much of each resource there will be available.
Almost all surgeons have a positive hospital contribution margin for their cases. If a case can
be performed safely, than it makes no economic sense to not perform the case. Allocating
Or time based on OR efficiency is rational.
Many hospitals have ICUs that often fill, causing delays or cancellations of surgical cases.
Other than staffing/building more beds, two strategies to deal with this:
- Adjust the days that services are scheduled to perform surgery to reduce the risk of
delays/cancellation.
- Provide surgeons with flexibility in the days when they have OR time, so that cases
can get onto the OR schedule to assure that the bottleneck (the ICU) is always full.
The bottleneck to carrying out surgery is ICU beds, then when there is ICU capacity
the case is done.
Day of the week is the best predictor of a service’s workload. OR allocations for each service
should vary by day of the week. One should calculate how many ORs should be staffed daily
for each service, and for each how many regularly scheduled hours of staffing is needed. To
1
, calculate: start with 0h and increase staffed hours until additional increases in staffed hours
causes the efficiency of use of OR time to decrease for that service. Increasing the staffed
hours causes the efficiency of use of OR time to increase progressively to a maximum, after
which it decreases. Allocating less hours then needed to complete the service safely leads to
over-utilized hours, and allocating more hours than needed is under-utilized hours.
The author recommends that each quarter, OR allocations be readjusted using data from
the preceding 7-11 months. Data can be obtained from OR info systems, EPD, billing data.
OR managers can schedule cases based on maximizing OR efficiency while leaving case
scheduling decisions to the convenience of surgeons/patients, by following three scheduling
rules:
- A service (surgeon) should not schedule a case into another service’s OR time if the
case can be completed within its own regularly scheduled OR time. OR allocations
are calculated based on expected workload on the day of surgery. Each service fill
their time at different rates.
- If a service (surgeon) has already filled its regularly scheduled OR time, then to
maximize OR efficiency, its new case should be scheduled into another services’
regularly scheduled OR time instead of in over-utilized OR time.
- A case should not be scheduled into over-utilized OR time if it can start earlier in
another service’s ORs.
de Bruin et al. (2009) Dimensioning hospital wards using the Erlang loss
model.
Most hospitals organize their beds into unit that are used by one or more clinical disciplines.
Nowadays it is also being organized based on length of stay (short/med/long), level of care
(intensive/med/normal) or urgency (elective, urgent, emergency). Distribution of beds is
based for big part on historically obtained rights. Capacity planning issues driven by
available budgets and target occupancy levels instead of service level standards (e.g. %
refused admissions, waiting times etc).
Also some data-issues: in Dutch hospitals registration is based on number of admissions, day
treatments, nursing days and no. of out-patient visits. Budget based on these parameters
via contracts with insurers.
A structural model of the patient flow through a clinical ward:
- Arrivals: patients arrive to the system and get admitted if there is a bed free. If not
then they are refused. There are scheduled and unscheduled arrivals.
2
